PoS(APCS2016)001 http://pos.sissa.it/ The Impact of the Space Ex- " published in 2004 by the Kluwer Accretion Processes in Cosmic Sources: † ∗ . [email protected] [email protected] periments on Our Knowledge of the Physics of the Universe Speaker. A footnote may follow. Young Stellar Objects, Cataclysmic Variables andGalactic Related Nuclei Objects, X-ray Binary Systems, Active This paper gets information from updated versions ofAcademic the Publishers, book reprinted from " the2004, review Space Sci. paper Rev. by 112, Giovannelli, 1-443The F. (GSG2004), review & is and Sabau-Graziati, a subsequent source L.: considered of lucubrations. of a the huge discussed amount arguments of can references. find Thus, an who almost wants exhaustive to list enter of in specific details references. in one In this review paper weevolution will of discuss all about objects the in accretionYoung the Stellar processes Universe. Objects that (YSOs), We regulates in will the Planets makeand (Pts), growth a in in and short White Black cruise Dwarfs Holes (WDs), discussingof in (BHs) the Neutron the accretion independent Stars in of arguments (NSs), their discussed masses. during this In workshop this on way we will mark the borders ∗ † Copyright owned by the author(s) under the terms of the Creative Commons c ⃝ Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). Accretion Processes in Cosmic Sources "APCS2016" 5-10 September 2016, Saint Petersburg, Russia Lola Sabau-Graziati INTA- Dpt. Cargas Utiles y CienciasArdoz, del Madrid, Espacio, Spain C/ra de Ajalvir, KmE-mail: 4 - E28850 Torrejón de Franco Giovannelli INAF - Istituto di Astrofisica eRoma, Planetologia Italy Spaziali, Via del Fosso delE-mail: Cavaliere, 100, 00133 Accretion Processes in Astrophysics: The State of Art PoS(APCS2016)001 Franco Giovannelli 1 Accretion is a universal phenomenon that takes place in the vast majority of astrophysical ob- Previously, essentially two schools of thought born in Cambridge (UK) and in Warsaw (Poland) When the first theories about accretion disks around compact stars started to be developed Accretion disks – mainly protoplanetary disks and those of binary stars – are of extreme inter- jects. The progress ofgreat ground-based amount and of space-borne information observational ondecades. facilities various The accreting has accretion is astrophysical resulted accompanied objects, inon by collected the the the process within surface of the of extensive last energyother an release elements accreting that of takes object the place flow and pattern.of in accretion The various theory, results gaseous which, of in envelopes, observationsphysical turn, inspired accretion conditions enabled the disk, in us intensive the jets development to surrounding study and intensive environment. unique study properties One is of of the accreting the most objects fact interesting and that outcomes accretion of processes this are, in a sense, self-similar on various spatial 1.2 Accretion processes in order to tackleSmak, with 1962, 1971, the 1981a,b, difficult 1984a,b; Paczynski, subject1984a,b 1965, and of 1977; the Bath, the references 1969, therein; 1975, mass 1976, Bathmental exchange 1978, et papers 1980, al., in about 1974; close accretion Mantle disks & binary& Bath, appeared systems Sunyaev, 1983). at 1973). (e.g. However, the two beginning funda- These oftion papers 1970s disks marked (Shakura, around substantially compact 1972, objects Shakura the inaccretion development disks binary of in systems, theories astrophysics until (see about present Giovannelli, times. accre- 2008). Pringle (1981) reviewed around the 1960s, the class ofposition the in astrophysics. so-called Cataclysmic They Variables constituted (CVs) thethe started perfect UV to laboratories window have for a to testing leading the thoseIUE theories. universe (International was When Ultraviolet opened Explorer), at CVs theobjects of became end the really of whole one 1970s astrophysics. of with the the advent most of interesting the class historical of 1.1 Some rightful historical remarks est, since they demonstrate thebig great number variety of of physical observational processes. manifestations Thetum and main transfer question allow in about studying the the a disks mechanism has ofthe not the interest been angular of momen- completely solved many yet, scientistsaccretion though for the onto several disks the decades. have central been From attracting object,in observations, which the one enables disk. can determining derive If the theviscosity one in rate rate supposes the of of disk, that then angular the one momentum finds angularhigh, that loss by momentum the 9-11 viscosity transfer orders coefficient of is in magnitude the drivenquestion, higher disks solely than should whether the by be the anomalously coefficient the of angular material molecular momentumand, viscosity. To if transfer answer so, is the to driven understand by therive nature developed the of turbulence parameters the in of turbulent turbulence viscosity, the one fromtherein). disk, should observational be data able, (Bisikalo if et possible, al., to 2016 de- and the references Accretion Processes in Astrophysics 1. Introduction PoS(APCS2016)001 Franco Giovannelli ). For a typical mass of a NS Edd 2 Accretion processes in different cosmic sources (after Scaringi, 2015). Figure 1: The observable physical quantity of radiation produced in accretion disks is the luminosity. As In accretion disks the high angular momentum, J, of rotating matter is gradually transported Accretion disks are the most common mode of accretion in astrophysics. The strong gravita- Accretion disks are flattened astronomical objects made of rapidly rotating gas which slowly Cataclysmic variable stars are unique natural laboratories where one can conductFigure the 1 detailed shows a sketch of cosmic systems where accretion processes occur (after Scaringi, photons carry momentum and thuswhich can gravity is exert able pressure to balance there the outward issymmetric pressure accretion a of flow radiation. maximum is The possible given limit luminosity for by a at the steady, spherically Eddington luminosity (L outwards by stresses (related to turbulence,of viscosity, shear J and allows magnetic matter fields). to This progressivelyenergy gradual move of loss inwards, the towards gaseous the matter centreradiation, is of thereby which gravity. converted partially The to gravitational escapes heat.thus and A governed fraction cools by of down a the the non-linear heat combinationviscosity, accretion is radiation of disk. and converted many into magnetic processes, fields Accretion including (e.g. disk gravity, Menou, hydrodynamics, physics 2008). is tional force of the compactsome object angular attracts matter momentum from anddirectly the conservation into companion. the of compact The angular object. infalling momentum matter have prevents matter fromspirals falling onto a central gravitating body.cretion The disks gravitational powers energy stellar of binaries, infalling active matter galactic extracted nuclei, in proto-planetary ac- disks and some GRBs. observational study of accretion processes and accretion disks. 2015). Accretion Processes in Astrophysics scales from planetary systems tojects galaxies. that, by This various fact reasons, gives are us not new available opportunities for direct to study. investigate ob- PoS(APCS2016)001 Franco Giovannelli 3 (Shapiro & Teukolsky, 1983). Since accretion disks 1 − erg s 38 10 × 2 ≃ Edd ), L ⊙ 4 M . 1 100 pc – giant molecular clouds; 10 pc – molecular clouds; 0.1 pc – molecular cores; 10 kpc – spiral arms of the Galaxy; 1 kpc – H I super clouds; ≃ It is important to say some wordsThe about process that the governs pathway the that global structure matter from covers large-scale from properties of interstellar the ISM to stars Our current understanding of the physical processes of star formation has been reviewed by Many papers, reviews, and books have been published about the accretion processes in cosmic • • • • • NS medium (ISM) up to form a star. is called fragmentation.clouds, It which may is themselves a break into hierarchicalElmegreen, smaller 1998) process structures. that It in ranges is from which a scales multiscale parent of: process clouds (Efremov & break up into sub- Larson (2003), with emphasisnearby. on The processes dense occurring coresterized in of by the molecular these runaway clouds clouds growth of are likeas a predicted central collapse those density to can observed peak undergo occur, that gravitational rotation evolvesresult towards and collapse is a magnetic singularity. that charac- As a fields long very do smallinitially not embryonic high change star but or this declines protostar with qualitative forms time behaviour. andof as grows The the the by surrounding remaining accretion envelope matter is at depleted. a tois rate Rotation form not that causes a well some is disk understood around and theple may systems protostar, be in but variable. which accretion Most, gravitational from interactions andand can protostellar possibly driving play disks all, a episodes stars role of form in disk redistributing inyoung angular accretion. binary stars momentum or such Variable multi- accretion as may flareupsof account and stars for jet will some production, also peculiarities have andin of important protostellar the implications densest interactions for environments in by planet forming processesinteractions formation. systems that and are The mergers. not most yet massive well Theformation stars understood and formation form but growth of may of include massive the black violent most holes in massive very stars dense may environments. have similarities to the sources (e.g. Shakura,1985, 1972; 1992, Shakura 2002; & Lewin, Sunyaev,& van 1973; Papaloizou, Paradijs Pringle, & 1996; 1981; van Lynden-Bell,Chakrabarti, Frank, den 1996; 2004; Heuvel, King Meyer-Hofmeister Abramowicz 1995; & & & Raine, PapaloizouVelázquez, 2014; Fragile, Spruit, & Falanga Lin, 2013; 1997; et al., 1995; González Hartmann, 2015; Lin Martínez-País, Lasota, 1998; 2016; Shahbaz Hartmann, & Herczeg & Casares Calvet, 2016). 2. Star Formation Accretion Processes in Astrophysics (M are not spherical and often havewith additional stresses gravity, that they can may counteract be thePacucci, brighter radiation Volonteri & pressure than Ferrara, along this 2015; limit Pacucci, and 2016; Sakurai, radiate Inayoshi at & super-Eddington Haiman, luminosity 2016). (e.g. PoS(APCS2016)001 (2.1) Franco Giovannelli ⊙ ⊙ L M / / L M × 9 10 4 × 3 . 7 = life T A schematic diagram of the sizes and durations of star formation in different regions (adapted 100 AU – protostars. Specifically, stars had to evolve as a strong function of their mass. Key were hydrogen fusion Stars are the final step of fragmentation. The first four items are large-scale structures in terms Figure 2 shows a schematic diagram of the sizes and durations of star formation in different • lifetimes. From early calculations itfor was billions easily of recognized years. that On low-mass theof stars other magnitude can hand, larger massive burn than stars hydrogen low-mass radiate stars. energythat Since at their a their fusion rate mass lifetime which is is is only much many a smaller.years orders few In and ten fact, less. for times Stars massive larger burn O this about stars means lifetime 10% it of is of stars of their by: the hydrogen order and of as ten a million rule of thumb one can estimate the of fragmentation and their stability islast determined two by items thermal, are magnetic small-scale structures andpressure. and turbulent are support. Open predominantly The issues supported by relate thermal todelay and questions gravitational magnetic collapse. of A whether deep magnetic discussionin fields can the be can book found really in of prevent the Schulz or paper (2012). by at Elmegreen least (2002) and Figure 2: from Efremov & Elmegreen, 1998). regions (Efremov & Elmegreen, 1998). Accretion Processes in Astrophysics PoS(APCS2016)001 Franco Giovannelli (Lazarian, de Gouveia Dal Pino & 5 Magnetic Fields in Diffuse Media are the mass and luminosity of the Sun and M and L the same for the star ⊙ and and L ⊙ Before the space era, practically all observations of PMSSs were only restricted at the optical The study of Pre-Main Sequence Stars (PMSSs) is of great interest as it provides crucial in- A substantial progress has been made in the field of magnetic fields in diffuse media in the Indeed, astrophysical plasmas are magnetized and turbulent and this presents a serious chal- However, it is interesting to remark the importance of magnetic fields from diffuse media to and near-IR (NIR) spectralthey regions. are sites With of the aoutflows. nowdays variety The of knowledge presence extraordinary of of astrophysical PMSSs, anKeplerian processes, we accretion differential including disk rotation accretion can have (Hartmann disks say been & and FU that strengthened Kenyon, Ori, by 1987a,b) a the in young observation the stellar ofby optical object nearly the (YSO) and presence whose of NIR a spectral spectra disk. energy of distribution (SED) can be explained formation on stellar evolution and,accretion particularly, of on matter, the and role mass loss ofcesses processes, magnetic of as the fields, well Sun angular as and momenta, indirect Solar information system. on the formation pro- 3. Accretion in Young Stellar Objects last decade. The newaffected observations substantially allowed our to understanding map ofand magnetic the intracluster fields role medium. with of higher With magnetic better precision,theories fields computational of which in abilities key processes it the in became interstellar magnetizedin possible medium media. understanding to In the test particular, origin and essential reject and progresseration, evolution has in of been the magnetic achieved physics fields, of inturbulent magnetized magnetic the media. theory reconnection, of acceleration magnetic and field propagation gen- of cosmic rays in lenge for studying such apletely media. enigmatic and For this decades was turbulentcesses. constraining astrophysical the magnetic In progress fields particular, in were information understanding com- diffuse of key media, a astrophysical variety the pro- ofpoorly processes density constrained of values structures, of cosmic filaments, magnetic ray fields molecularThe propagation, and clouds, somewhat essential heat etc. ad processes hoc transport, models were related of treatedchange to magnetic using their magnetic turbulence. topology, fields, i.e. forrates instance, magnetic used the by reconnection, different ability were researchers of varying hotly by magnetic debated many fields with orders of to the magnitude. estimates of the compact sources. The book Accretion Processes in Astrophysics where: M (Unsoeld & Baschek, 2001). Clearly, thisclassification development put could an resemble end an to the evolutionarystars. perception scale that where the Draper early type O stars evolve into late type Melioli, 2015) presents the currentStarting with knowledge an of overview of magnetic twenty-first century fields instrumentationfields, in to the observe diffuse chapters astrophysical magnetic cover astrophysical observational media. techniques,basic origin processes of in magnetic magnetized fields, fluids, magnetic themedium turbulence, role and of for magnetic star. fields for cosmic rays, in the interstellar PoS(APCS2016)001 Franco Giovannelli 6 Sketch of the formation of a single star and the evolution of the circumstellar material. The left Class 0 objects are sources with a central protostar that are extremely faint in the optical and The evolution of YSOs has four different phases: Class 0, Class I, Class II and Class III. Class PMS is an important evolutionary phase of all stars, which are evolving from their birth to the Figure 3: panels show the SED of the systemsystem at geometry different (adopted evolutionary from stages. Andrea The Isella, right panels 2006, show after the André, corresponding 1994). 0 is observable only in submmradiation range. and Class an I, infrared II excess. and III TheClass sources amount II are of and characterized infrared III with excess objects a is are blackbody decreasing also during visible the in evolution. the optical bands (see Fig. 3). Main Sequence (MS), and thendue to to their their masses ultimate (or fate. luminosity).MS A Indeed, and as first therefore well the important known, experimental difference high studydue among mass of to stars stars their the evolve is evolution rapidly lack within into of the the ation PMS good towards phase statistics. the is On MS, very the difficult, can contrary,belonging be low to mass studied different stages stars, in of because details the of PMS since their evolutionary it phase slower (for is evolu- details possible see e.g. to Giovannelli, find 1994). large samples of objects Accretion Processes in Astrophysics PoS(APCS2016)001 yr), the 5 10 ≈ Franco Giovannelli 7 yr), and the existence of a stable planetary system by 7 yr). The formation of the disk occurs naturally. The disk 10 9 ≈ 10 ≈ yr that forms a core, through the active disk/outflow phase ( 4 The main stages of planetary formation from the collapse of an interstellar cloud (adapted from A discussion about the structure and evolution of pre-main-sequence circumstellar disks can Figure 4 shows even better the pathway for the formation of planets from an interstellar (IS) Stellar properties of embedded protostars have been reviewed by White et al. (2007) start- acts as a reservoir for material withDisks too emit much and initial reflect angular light momentum very tostar well fall with onto and the the can new central be instrumentation star. seen both to ground- relatively and large space-based distances in from different the energy central regions. the time the star reaches the MS ( passive disk/planet formation phase ( be found in the paper by Isella, Carpenter & Sargent (2009), and a deep discussion about the cloud in the case of Solar Systema (Beckwith timescale & of Sargent, order 1996). 10 From the collapse of the IS cloud in Figure 4: Beckwith & Sargent (1996). ing from the objective fact thatHerbig protostars Ae/Be are type precursors stars to undergoing thethey quasi-static nearly are contraction fully towards in assembled the the T-Tauri and zero-age processstars main of sequence; with acquiring spatially the extended majority envelope-like oftinction structures their has appear stellar inhibited to mass. observers fit from Althoughconfirming this directly numerous that description, measuring young they their their are stellar in high fact and ex- in accretion the properties main and phase of mass accretion (i.e., true protostars). Accretion Processes in Astrophysics near-IR and that have a significantevolved embedded submillimeter sources luminosity. with Class circumstellar disks I and sourceswith envelopes, (a SEDs they > are that optically 0) peak invisible are stars at relatively < mid-IR 0) to have significant far-IR circumstellar wavelengths.characterized disks, Class them. strong II, Class emission III, or lines weak classical and emissionand substantial T T negligible IR Tauri Tauri excesses, stars stars or they (a UV (-2 are < no excesses < -2) longer a have accreting weak significant or amounts no of emission matter. lines PoS(APCS2016)001 Franco Giovannelli 8 Origin of the spectral energy distribution: at larger wavelength, the disk emission outweighs the Wolf et al. (2012) present a review of the interplay between the evolution of circumstel- How do we know that disks exist? We have many inferences and proofs, like shown in Fig. 6 Circumstellar disks can be detected by several techniques, each tracing specific features, tem- lar disks and the formationcated of observations. planets, They both discuss fromof fundamental the circumstellar questions perspective disks of concerning and theoretical the planets models formationlong-baseline interferometers, which and and as can dedi- evolution well be as the addressed importancebaseline in of (sub)millimiter complementary the interferometers observations and near with high-sensitivity long- future IR with observations. optical and IR (after Beckwith, 1998). Figure 5: stellar spectrum. Generally, the shorterLarge wavelength wavelength emission (submillimeter) comes probe fromBirnstiel, the hotter, 2010, dust inner after regions from mass Dullemond of in et the the al., disk. 2007). outer, optically thin regions (adopted from peratures and/or regions of theexistence disk. of Combining disks this but knowledge alsodisk enables to mass is us probe expected not the to only reside physics in tothis which gas component proof (because is is the disks happening are the made inside hardest outof of to of the interstellar them. detect disk material), as and however Most it in of the is(SED) mid-plane. the often is The frozen schematically disk shown out, geometry in especially and Fig.for in the 5. disks according the around In spectral outer, young energy fact cold stars distribution this parts (e.g., IR Strom excess et was al. the 1989; first Beckwith observational et evidence al. 1990). 3.1 Disk observations Accretion Processes in Astrophysics formation and evolution of planetary systemsin can which be they found used in Spitzer the photometric paper and by spectroscopic Carpenter observations. et al. (2009) PoS(APCS2016)001 Franco Giovannelli 9 Inferences and proofs for the existence of disks (after Beckwith, 1998). Figure 6: Spectral Energy Distribution of XX Cha (Beckwith, 1998, 1999 after Adams, Lada & Shu, 1988). Chiang & Goldreich (1997) derived hydrostatic, radiative equilibrium models for passive disks Figure 7 shows the SED of XX Cha in which the IR excess clearly demonstrates the presence surrounding T Tauri stars. Each disk isThis encased by layer an reemits optically directly thin to layer space of aboutinward superheated half dust and the grains. regulates stellar the energy interior it temperature absorbs. ofit The the absorbs other disk. more half The is stellar heated emitted radiation, disk especially flares.spectral at As energy large a distribution radii, contributed consequence, than by a the disk flatfixed is disk frequency, fairly would. the flat The contribution throughout portion the from of thermal the the infrared. surface At layer exceeds that from the interior by about a Figure 7: of an optically-thick, geometrically-thinLada circumstellar & disk Shu, 1988). (Beckwith, 1998, 1999 after Adams, Accretion Processes in Astrophysics PoS(APCS2016)001 > ⋆ Franco Giovannelli 10 Frequency of detections as a function of cluster age for several star-forming regions observed by Observed Spectral Energy Distribution of GM Aur, and flared radiative equilibrium disk fit to GM While it appears that most young stars form accompanied by a circumstellar disk, it is not clear Beckwith (1998) derived from the paper by Chiang & Goldreich (1997) the SED of the T ISO, IRAS, and ISOPHOT (adapted from Beckwith, 1998 after Meyer & Beckwith, 2000). that all disks form planets.accretion disk. Several It factors has could been play suggested a that crucial disks evolve role more in quickly determining around high the mass fate stars of (M an Figure 9: Tauri star GM Aur, reported in Fig.clearly 8, illustrated. where the contribution of the different part of the system are Figure 8: Aur. The contribution of theChiang different & component Goldreich, of 1997). the system are clearly indicated (Beckwith, 1998 after Accretion Processes in Astrophysics factor 3 and is emitteddust at grains more in than the an superheated layer order appear of in magnitude emission greater if radius. the disk Spectral is features viewed nearly from face-on. PoS(APCS2016)001 Franco Giovannelli 20 mm), useful for giving answers to − 02 . 0 ∼ 11 yr, the collapsing cloud has formed a Class I object consisting of a heavily 5 10 ∼ Uncertainties on interstellar opacities. The light brown ellipse mark the zone covered by the ) compared to low mass stars (Natta, Grinnin & Mannings, 2000). Meyer & Beckwith yr, the star becomes optically visible above and below the plane of the disk, although the ⊙ 6 Following the paper by Linsky & Schöller (2015) the evolution of YSOs from dense clumps Updated Catalog of Circumstellar Disks can be found at http://www.circumstellardisks.org/ Dust opacities are relevant for dense regions in molecular clouds and for protoplanetary ac- 10 0 M . visible spectrum is veiled by emission(CTTSs) from or the Class disk. II These objects. starsgas Strong are along UV called magnetic emission Classical field seen T lines in Tauri from stars CTTSs the results disk mostly to from the accretion star, producing of postshock regions with strongly of interstellar gas and dustMontmerle, to 1999), main as sequence shown in starsobject) Fig. proceeds consists through 3. of several a The stages collapsing earliestlengths. (Feigelson massive phase & disk After of detectable a only protostar atobscured (referred millimeter star to and heated as far-infrared a by wave- Class the∼ 0 release of gravitational energy and a large circumstellar disk. After (Created by Caer McCabe.Last updated Redesigned April by 29, Isabelle 2016). H.and the The Jansen. debris total disks number Maintained are of 41. by resolved Karl disks is Stapelfeldt. 170, the3.2 PMS T disks Tauri are Stars 129, Figure 10: cretion disks. Thisknowledge problem of opacities was is discussed important in bycontribution order Henning, to will settle be Michel the given controversy by & among the models.dashev Stognienko MILLIMETRON et An (1995), Space al., important Observatory 2014) and (Smirnov which et the will al., operate 2012; in Kar- a region ( Millimetron (after Beckwith, 1998 and Giovannelli, 2010). Accretion Processes in Astrophysics 1 (2000) reviewed the observed correlations ofISOPHOT. disk properties Figure with 9 time as shows studied thecluster from age frequency ISO, for IRAS, of several star-forming detections regionsor observed. of coagulate It optically-thick into appears disks larger that bodies optically-thick as disks onphase a dissipate a in timescale function T comparable Tauri of disks to (Beckwith, the 1998 termination after of Meyer the & main Beckwith, accretion 2000). the uncertain values of insterstellar opacities, as shown in the Fig. 10 (light brown ellipse). PoS(APCS2016)001 ). TTSs are 4 10 Franco Giovannelli − 3 yr (e,g. Giovannelli, 7 10 10 ∼ − 5 10 ∼ ; age: ⊙ 3 M ≤ 12 M ≤ ⊙ 4000 K); masses: 0.5 M yr, most of the gas and dust from the disk has condensed into planets or has been 7 ∼ 10 Magnetically funneled accretion stream producing broadened emission lines (after Hartmann, ∼ Beckwith et al. (1990) from a continuum observations at 1.3 mm of 86 pre-main-sequence After a long multifrequency campaign of observations of the CTTS RU Lupi (Giovanelli et al., One of the most intriguing problem is connected with the origin of magnetic field. This ar- The importance of a deep study of TTSs is based among others because they probably look 4. Formation of planets stars in the Taurus-Auriga dark cloudsticles. showed that The 42% detected have detectable fraction emission is from only small slightly par- smaller for the weak-line and "naked" T Tauri stars 1995) and the subsequent derived& model Montmerle (Lamzin (1999, et after al., Hartmann, 1996),stream 1998) magnetically the – funneled proposed shown produces model broadened in by emission Fig. lines.the Feigelson emissions 11 The are different – zones clearly can interested marked be in in confirmed: Fig. 11. an accretion gument has been deeply discussed bymagnetic Feigelson fields & directly, Montmerle and (1999). inspots It most or is cases, high difficult energy indirect to radiation tracers study produced of YSO by magnetic violent field activity reconnection such must as be cool used. star like the Sun in its very early stages (although with a scaling factor of Figure 11: 1998 and Feigelson & Montmerle, 1999). The dimensions marked are not in scale. subgiant of late spectral type (laterFeII than emission K lines, up strong to IR M5.5)K and excess; (typically show T the high underlying variability, photospheres strong1994). HI, are CaII, relatively cool: T < 6000 Accretion Processes in Astrophysics enhanced emission in the HeI 5876postshock region, and closed-field other lines lines. in Strong theinteract. stellar X-ray corona, emission In and can where the be stellar produced last and in stageyears disk the of and magnetic fields evolution to the main sequence, which occurs between a few million accreted onto the star, whichWTTSs is are now often called called a naked Weak-lined Tobscured TTSs by Tauri because star a their disk. (WTTS) ultraviolet or emission Class line III spectrum object. is no longer PoS(APCS2016)001 Franco Giovannelli that is a serious problem in the (e.g., Calvet, Hartmann & Strom, 2000; ⊙ 13 –0.1 M 3 − 10 ∼ the angular momentum problem 10–1000 AU and a mass of ∼ Observations also indicate that a younger protostar has a massive circumstellar disk (Natta, Stars form in molecular clouds that have an angular momentum (Arquilla & Goldsmith, 1986; Following the very interesting paper by Machida, Inutsuka & Matsumoto (2010) and refer- Meyer et al. (2002) discussed the formation and evolution of planetary systems utilizing the This fact is supported also by the observations of submillimeter flux densities from the cir- Natta, Grinin & Mannings, 2000).Because However, the they formation correspond site to of phases the circumstellar longenvelope, disk after we and their cannot protostar formation. directly are embedded observe in newbornThus, a or we dense very infalling only young observe circumstellar the disks circumstellarII disks (and protostar long phase. protostars). after their formation, i.e., around the class I or Goodman et al., 1993;natural Caselli, consequence of 2002; the star 2003). formationcollapsing process when Thus, cloud the core. the angular momentum appearance In isaround of conserved addition, the in a protostar observations the (e.g., have circumstellar Watson et shown disk al.,Numerous the is 2007; existence observations Dutrey, a Guilloteau of indicate & circumstellar Ho, that 2007; disks circumstellarsize Meyer et of disks al., around 2007). Class I and II protostars have a ences therein), we believecircumstellar that disk is stars coupled are with born with a circumstellar disk. The formation of the star formation process, and theprotostar dynamics of that disks determines may the determine finalcircumstellar the stellar (or mass mass. protoplanetary) accretion disk, rate In and onto addition, theirerties the planets formation such are process as considered strongly disk depends to size on formprovide and disk a in mass. prop- significant the Thus, clue to the star formation and and planet evolution formation. of the circumstellar disk can sensitivity of SIRTF (the Space Infra-Red Telescopeto Facility) through carry the out Legacy Science spectrophotometric Program observationsproperties of around solar-type a stars. representative Theyprocess sample derived of of circumstellar agglomerating primordial dust into disks planetesimals)ated and (dominated dust) debris by over disks the ISM (dominated full grainssystem by range formation in collisionally of and gener- the evolution. dust Hillenbrand disk (2008) optical-depthstimescales discussed diagnostic disk-dispersal starting and of that planet-formation the well major beforecepted phases the knowledge of that existence planet most of – exo-solarto-several if systems million not was all years confirmed, – of it stars theirhave possess was the pre-main circumstellar ac- potential sequence material to lives, during form and the planets. first thus one- that these systems commonly cumstellar disks around 29 pre-main-sequenceof stars these (Beckwith disks & are Sargent, of 1991).solar special nebula. interest, The Studies because properties of they such bear systemsof may many planetary therefore similarities systems lead to like to those a our of better own. understanding the of primitive the formation Accretion Processes in Astrophysics than for CTTSs, indicating that thehas former stars an often angular have circumstellar momentum material.very comparable The little to typical stored disk that energy, almost generally five ordersresults accepted of demonstrate for that magnitude disks smaller the more than early massive that thanmonly solar of the minimum the accompany nebula, mass central the of but star. birth the Their proto-solar of system solar-massthe com- stars Galaxy. and suggest that planetary systems are common in PoS(APCS2016)001 , and D between D value equal to α , they show that Franco Giovannelli α , the initial radius R D 02) are charaterized by hydrodynamical . 0 1) are characterized by a MHD turbulence must be between 8 and 28 AU, M < < D α α < 14 < . However, they conclude that forming the cores of 02 . α 003 . years in the extreme case. 5 , and the coefficient of turbulent viscosity D must be between 0.003 and 1. α . 4 , and − ⊙ around class 0 sources, indicating that this massive disk can be present early in , its initial radius R ⊙ D 1 M The high viscosity disks they infer (0 The strength of magnetic fields calculatedwith from the their remanent selected models magnetism of foundfields nebula in was is carbonaceous short, consistent no chondrites. more than The 10 lifetime of magnetic The enrichment in fossil deuterium enrichmentdance in is water by with far respect more to constraining. the At protosolar t abun- = 0, R Theories of the formation ofparameters giant which planets define provide the relatively nebula,the weak namely coefficient the constraints of initial on turbulent mass the diffusion M main turbulence. Other mechanisms susceptible toobservations generating seem a to turbulent be nebula ruled compatible out. with 0.03 and 0.3 M while their low viscosity models (0 giant planets in a time compatibleat with least the a lifetime few of 10 the nebula requires a ∼ Now we can say that over the past 20 years abundant evidence has emerged that manyMeyer (if et not al. (2007) reviewed on developments in understanding: i) the evolution of the gas and Drouart et al. (1999) starting from the fact that each nebula disk is characterized by its ini- For this reason Machida, Inutsuka & Matsumoto (2010) investigated the formation and evo- • • • • disk all) stars are born with circumstellar disks.provide strong Understanding constraints the evolution on of theories post-accretion of disks planet can formation and evolution. dust content of circumstellar disks based on observational surveys, highlighting new results from these parameters may be constrainedsen by physical comparing and temperature-density chemical profiles Solarfruitful to properly comparisons System cho- with data. available Solar Theythe System developed primitive solar an data nebula, and analytical as helpful model summarized below: constraints that on permits the structure of tial mass M lution of the circumstellar disk indynamic unmagnetized simulations molecular from clouds using the three-dimensionalcalculations prestellar hydro- indicate core that until the thedisk planet end in or the of brown-dwarf main the massstrong accretion main object time phase. accretion variability may that phase. form In is in causedthe addition, Their by circumstellar the the the disk. circumstellar mass perturbation of accretion Such proto-planetscompanion variability rate and/or in provides onto the the a circumstellar spiral the useful disk arms protostar around signature in very shows for young detecting protostars. the planet-sized Accretion Processes in Astrophysics Grinin & Mannings, 2000; MeyerM et al., 2007). Enoch et al. (2009) observed a massive disk with the main accretion phase. However,circumstellar unfortunately, disks, observation cannot and determine how thetion and real when process sizes they of of form. thesimulation circumstellar Therefore, are disk necessary we to by cannot investigate observations. the understand formation the and The evolution forma- of theoretical the approach circumstellar and disk. numerical PoS(APCS2016)001 Franco Giovannelli 3 Gyr, Meyer et al. (2006) ∼ Jets, disks and the dawn of planets 3 Myr to ∼ 15 328 stars ranging in age from ∼ JEDI (JEts and Disks at INAF) meeting about nd Considering that star and planet formation are the complex outcomes of gravitational collapse Recently, investigations about the possible correlation between the mass accretion rate onto Protoplanetary disks dissipate rapidly after the central star forms, on time-scales comparable The 2 With a sample of and angular momentum transportLodato mediated (2016) by deeply protostellar discuss on andlight the open protoplanetary role questions disks, related of Kratter to gravitationalof & instability the mode-mode coupling development in in of this setting a process.Gravitational the turbulent instability maximum They cascade provides angular efficient high- in momentum angular thin transport momentum disks rate transport in and in thick the relatively disks. massive role pro- the central young star and the mass– of have the been surrounding protoplanetary performed. disk –determined For theoretically the instance, predicted photospheric parameters, Manara mass et accretion rate, al.plete and sample disk (2016) of mass young for have an stars accurately essentially withmass and com- disks accretion homogeneously in rate the Lupus and clouds.pected the viscous They disk found timescale dust a when correlation mass, assumingthat between an mass with the accretion interstellar a rates medium are ratio gas-to-dust related thatmeasurements to ratio. in the is properties different This roughly clouds of confirms the in consistent outer order disk. with to better We the expect determine in ex- such the a near correlation. future traced the evolution of circumstellar gascircumstellar and disks dust from through primordial to planet-buildingservational stages older program, in collisionally they young coordinated generated a debris concomitantdynamics disks. theoretical of effort circumstellar aimed In at dust addition understandingenergy with the to distributions, and and the atomic without ob- and the molecularthese effects gas efforts can line of provide emission. an embedded astronomical Together planets, with contextits for the habitable dust understanding observations, planet whether spectral – our is solar a system – common and or a rare circumstance. to those inferred for planet formation.the In order dispersive to effects allow of the UV formation and ofdepletes planets, X-ray significant disks photoevaporation amounts must for of survive at the least massinternal a in and few gas Myr. external and Viscous irradiation solids, accretion while removein photoevaporative most flows solids of driven by and the some gas. gasderstanding A get of reasonably disk incorporated large evolution into fraction and of planets.They dispersal, also the and discuss Gorti mass existing discuss et observational how constraints al. these onIn dispersal might the mechanisms (2016) affect near and review planet future future our directions. it formation. is currentstand desirable un- the to close, be able and to perhaps connectdisk causal, disk dispersal. correspondence evolution to between planet timescales formation for and planet under- formation and Accretion Processes in Astrophysics the Spitzer Space Telescope; ii) thethe physical survey properties results; of specific iii) systemsmodel as theoretical of a models our means used to own interpret solarstars; to and system explain v) how for the these comparison results observations; impactor to our iv) rare the assessment compared an of observations to whether evolutionary the of systems ensemble like debris of our disks own normal are stars around common in other the disk of the Milky Way. has been very interesting.ii) Disk The Accretion proceedings and contain YSOs;(Antoniucci iii) papers et Jets al., about: 2015). and Winds; i) iv) Early Physical Protostellar and Chemical Phases; Properties of Disks PoS(APCS2016)001 Franco Giovannelli 16 The Exoplanet Data Explorer is an interactive table and plotter for exploring and displaying The list of the potential habitable exoplanets updated to 23rd July 2015 (Planetary Habitable Figure 12 shows the distribution of Kepler planet candidates by size as of January 2015 (Image The research of potential habitable exoplanets has been strongly supported during last two The most important questions about the possible origin of life in our Universe became a real What we can say about the step from disk to planet? Thanks to the unprecedented sensitivity Casanova, Lazarian & Santos-Lima (2016) consider formation of accretion disks from a real- data from the Exoplanet Orbitcompilation Database. of The quality, Exoplanet spectroscopic Orbit orbital Databasethe parameters is peer-reviewed a of literature, carefully exoplanets and constructed updates orbiting the normalof Catalog the stars of Exoplanet from nearby Orbit exoplanets. Database and Ain Explorers detailed CSV format was description was published updated by on Han 2015/07/06 et and al. is (2014). available at The http://exoplanets.org/csv. latest list Laboratory - PHL -exoplanets-catalog) University contains of 31 Puerto objects: RicoFigure 10 13 at Earth–size shows Arecibo, planets such http://phl.upr.edu/projects/habitable- andnumber potential of 21 habitable such super-Earth–size exoplanets exoplanets. planets. is rapidly This increasing. list is continuously updated and the Credit: NASA Ames/W Stenzel). As wehood can of see solar there system. are 808 Earth-like planets in the neighbour- decades. Indeed, this field of astrophysicsplanets is Earth-like now could probably open the a most serious exciting debate since about the the discovery of possibility of life outside of solar system. 4.1 Habitable Zone in the Milky Way and Exoplanets scientific question in the lastmust couple orbit decades other when stars. itoptical appeared And astronomers a detected yet, near small it changes certainty in could thata stellar not other few, emission and planets be which now revealed proven, many, the planetary untildistinguish presence systems them the of around from first early our other own 1990’s. stars. solar systemareas/exoplanet-exploration/). We Then, neighbors call (http://science.nasa.gov/astrophysics/focus- radio these planets and "exoplanets" to and imaging capabilities offered by theformed Atacama our Large understanding Millimeter of Array protoplanetary (ALMA)discuss we disks the have and, main trans- hence, results ofplanetary and planet disks caveats formation. based related on Isella to millimeter-waveALMA (2016) the observations. observations measurement Then of of he the the presentbe HL mass a due Tau of recent to disk, solids the analysis which tidal of inconclusion, suggests interaction the proto- Isella that between (2016) Saturn the argues mass that observed the planetsplanets circular existing and might rings observations form the of very might circumstellar protoplanetary early material. disks on, suggest perhaps In that at the the same time as the formation of the disk itself. istically turbulent molecular gas using 3Dof MHD the simulations. fast turbulent In reconnection particular, they forical analyze the simulations the removal effect of they magnetic demonstrate fluxresolving how from the the a so-called disk. "magnetic fast braking With reconnection catastrophe". their enables numer- protostellar disk formation Accretion Processes in Astrophysics tostellar disks. Evidence ofthe this coming phase years observationally with more remains ALMA sparse data. but is likely to improve in PoS(APCS2016)001 100 days. − 1 Franco Giovannelli ≈ and periods in the range ⊕ 17 Current potential habitable exoplanets (2015, credit: PHL@UPR Arecibo). The distribution of Kepler planet candidates by size as of January 2015 (Image Credit: NASA Figure 13: Coughlin et al. (2016) presented the seventh Kepler planet candidate (PCs) catalog, which In the NASA Exoplanet Archive it is possible to find updated plots about the Kepler planet is the first to belight based new on PCs the that entire, arestars, uniformly many both of processed, potentially which 48 orbit rocky month solar-type and stars. Kepler potentially dataset. This in work represents They the significant high- habitable progress zone in accurately of their host candidates and all confirmed planets.planets Figure in 14 blue (Nasa (Mullally Exoplanet et Archive) al.,mass shows (Earth 2015) 4175 masses) among versus confirmed the period (days). whole It setof is of impressive confirmed planet to planets note candidates with that in there masses is red in a in the strong the concentration range plane 1-10 M Ames/W Stenzel). Figure 12: Accretion Processes in Astrophysics PoS(APCS2016)001 4 ∼ Earth- 6 10 × there are 808 3 133 Franco Giovannelli ≈ 2 pc ≈ ) exoplanet within the habitable zone ⊙ 2.5 R < 18 . Therefore, if in a volume of 1 kpc, as evaluated by the differential rotation of the 3 ≈ 10% of the total number of stars in the Galaxy. Taking into 330 kpc ≈ ∼ 11 kpc, as shown in Fig. 15 (after Lineweaver, Fenner & Gibson, ∼ Radius – Period distribution of confirmed planets (blue points) and candidates planets (red For life-forms like us, the most important feature of Earth is its habitability. Understanding Studies about exoplanet predictions around stars have been performed by Bovaird & Lineweaver The presence of numerous exoplanets in the vicinity of solar system – within a distance of 8 pc – plays an important role in speculating about the possible number of such exoplanets . 0 like planets. It is evidenthigh. that the Next probability of generation findingabout instruments numerous this ground– habitable intriguing planets problem. and becomes space–based very will provide valuable information of KOI-812 and that the average number of planets in the habitablehabitability zone and of using a that star knowledge is tosurvival 1–2. locate as the a nearest species. habitable planethabitable During may planets the have be been past crucial bolstered decade, for by our expectationsments the increasingly that known large the to overlap universe between harbor terrestrial could life environ- The be and inhabited filled the and with variety uninhabited of regions environments onare on Earth the tell newly main us detected constraints that rocky that temperatureLineweaver exoplanets. can and & be the Chopra used presence (2012) in of a compiled water habitability and classification reviewed scheme the for recent rocky exoplanet planets. detections suggesting (2013). They predict the existence of a low-radius (R Figure 14: points) (NASA Exoplanet Archive). ∼ within the whole habitable zonekpc of and our an galaxy. external Such radius habitable of zone has an internal radius of Earth-like planets detected, in the habitable zone of our Galaxy we could expect 2004), where the habitable zoneof in stars a Milky contained Way-like in galaxy thisaccount is zone represented that in is the green. thickness The ofGalaxy, number the the habitable disk volume is is Accretion Processes in Astrophysics determining the fraction of Earth-size planets in the habitable zone of Sun-like stars. PoS(APCS2016)001 Franco Giovannelli " (Cleeves et al., 2014) 19 100%, and that the fraction with rocky planets may be ∼ The ancient heritage of water ice in the solar system Habitable zone of a Milky Way-like galaxy (after Lineweaver, Fenner & Gibson, 2004). Astrobiology is an interdisciplinary scientific field, recently born, not only focused on the However, we have interesting news about the presence of water in the universe. We knew that Earth is located in a dangerous part of the universe. Threats to life on Earth are manifold and Figure 15: has carried the knowledge oneoceans, step and further. is It present in is other understoodto solar that that system the in bodies, water has the now remained interstellar presentof virtually medium. in unchanged planet with Earth’s This formation. respect means This that allowsemergence this us of water to has life understand not are that changedsystem. the not during They initial unique, the can, conditions however, process i.e. be that common have in favored not space. the dependent on the unique characteristics of our solar search of extraterrestrial life, butenabled also the on deciphering emergence the of key lifeis environmental on fundamental parameters knowledge Earth. that have necessary Understanding notets, these only but physical for also and discovering for chemical life(2017a,b) understanding or parameters presented our signs an own of interdisciplinary terrestrial life reviewmajor on environment. advances of and other current main Recent plan- outlooks research in papers in theunderstanding by field. astrobiology, of They covering Cottin planetary reviewed the system the et most formation al. versity recent including of discoveries, the the planets, new the specificity origin of of the water Earth on among Earth and the its di- unique combined properties among solvents all the water found on Earth, hasthe been contrary, transported the by work small " bodies such as comets and asteroids. On range from asteroid impacts toinduced supernova disasters. explosions If and the survival from of supervolcano theEarth human eruptions has species to to is human- to spread be to ensured other for planetaryand the bodies. long is term, Mars the then is life the second on most closestabundant Earth-like planet planet; water we and further currently know it carbonideally possesses dioxide, suited a together to moderate with be surface a a gravity,can first range be an colonization accomplished of atmosphere, target. is essential via Here a minerals. we series2013). of argue initial Thus, that one-way the human Mars most missions is (Schulze-Makuch practical & way Davies, that this that the fraction of stars with planets is Accretion Processes in Astrophysics comparably large. They reviewedan extensions abiogenesis to habitable the zone circumstellar and the habitable galactic zone habitable (HZ), zone. including PoS(APCS2016)001 (Lipunov, " by Andrew m to 20 mm, µ Franco Giovannelli , rotating with rota- µ ⃗ gravimagnetic parameter is called 2 µ ˙ M/ 20 Accretion, Black Holes, AGN and All that... (Giovannelli, 2016). The parameter y = ⃗ ω Gravimagnetic rotator: a body with mass M, having a magnetic moment Starting from the trivial definition of X-ray Binary Systems (XRBs): they are binary systems However, if we insist in looking for life which is like our own, why do we look for ... INTEL- For a general deep tutorial lecture see " An intriguing question about the probability of finding a number ofFor civilization years, in the the Galaxy search for manifestations of extraterrestrial civilizations has been one of hu- 1987; Lipunov & Postnov, 1988). emitting X-rays, a natural question arises.independent Are of these their systems nature? governed by The fewMass physical answer XRBs parameters is (LMXRBs), Anomalous positive. X-ray Indeed, Pulsars High (AXPs), Mass and Cataclysmic XRBs Variables (HMXRBs), (CVs) Low can Figure 16: LIGENT LIFE? (Giovannelli, 2001). 5. Accretion onto compact objects King (http://www.exp-astro.phys.ethz.ch/seminars/LecturesunderscoreKing.pdf). arises. It is now evident that Drake’s formula (Drake, 1962) must bemanity’s object most of a ambitious robust revision. projects.sages from Major extraterrestrial civilizations, efforts and(Dyson,1960). are the now millimeter The range focused Millimetron is space ontions promising observatory the to for is probe these interception aimed a purposes at of broad conducting range mes- astronomical of objects observa- in the Universe in the wavelength range 20 Accretion Processes in Astrophysics for the emergence of life, thethe idea inventory that of endogenous the and Earth exogenous could sources havechemistry of been could organic habitable matter evolve during and towards the new concepts Hadean biologicalnew about Era, molecules findings how show and the remarkable biological potential systems. lifements. has All In for those adaptation addition, results and many survival from in differentto extreme fields look environ- of for science life are in guiding other our Solar perspectives System and objects strategies as well as beyond, in extrasolar worlds. including the search for extraterrestrialreferences life therein). (Smirnov et al., 2012; Kardashev et al., 2014, and the tional velocity PoS(APCS2016)001 , µ ⃗ gravimagnetic Franco Giovannelli . The symbols used vs Log y (Lipunov, 6 − , named is expressed in seconds spin 2 cm µ 2 spin − ˙ M/ G 1 − g s 42 − 21 , being the two axis not necessarily coincident, as sketched in ⃗ ω (Monte Carlo simulations of binary evolution) permits to build up the –Log y, reported in the upper panel of Fig. 17. P spin Upper panel: distribution of magnetic rotators in the plane "Spin Period" – "Gavimagnetic , all the gravimagnetic rotators are contained in a plane Log P Scenario Machine The Figure 17: Parameter" (adapted from Lipunov, 1995); lower panel: classification of rotators (Lipunov, 1987). for the different types ofthe binaries characteristic are radii explained can in bevarious the found types of lower in rotators panel the are of paper reported by Fig. in Fig. Lipunov 17. 18 (1987). (Lipunov, 1987). The Observational examples definition of of complete picture of all possible evolutionaryequation stages (5.1) used of for binaries 500,000 in systems the containingin magnetized Galaxy. the stars The plane provided basic the Log results evolution P contained Accretion Processes in Astrophysics be considered as gravimagnetic rotators: a bodyFig. with 16 mass (Giovannelli, M, 2016). having Introducing a a magnetic physical parameter, moment y = and the gravimagnetic parameter is expressed in unit of 10 rotating with rotational velocity parameter 1987; Lipunov & Postnov, 1988). PoS(APCS2016)001 ∼ (5.1) Franco Giovannelli 2 3 t µ t R κ − su K 22 ˙ M = ω dt dI Observational examples of rotators (Lipunov, 1987). Figure 18: for Keplerian disk accretion; d for wind accretion in a binary; R x 2 g R Ω GM t 0 for a single magnetic rotator; √ η Indeed, Raguzova & Lipunov (1999) calculations show that binary black holes with Be stars Belczynski & Ziolkowski (2009) used binary population synthesis models to show that the Using the "Scenario Machine" Raguzova & Lipunov (1999) obtained an evolutionary track = specific angular momentum applied by= the accretion matter to the rotator; = ∼ = radius of the inner disk edge; = characteristic radius; = 1/4 (Illarionov & Sunyaev, 1975); = dimensionless factor; = rotational frequency of the binary system; su su su su t d t t ˙ must have 0.2 < etroscopic < variations 0.8. occur in It athe is relatively systems particularly small are difficult portion observed to of at the detectformation of orbit, widely such 1 and separated systems Be/BH could as epochs. system. easily most They be of missed found their if for spec- 20-30expected Be/NS ratio systems of the Be/XRBs with neutron30-50 stars Be/NS to systems black the holes formation in of the 1 Galaxy Be/BH is system, relatively and high: so for broadly in line with observations. κ R M = accretion rate in different regimes. that can lead to theexistence formation of of binary Be/BH black systems. holescovered on The in eccentric the modern orbits near evolutionary around future... scenario Be Like predicts happened! stars the and such systems may be dis- K R η where: K K K Ω Accretion Processes in Astrophysics PoS(APCS2016)001 Franco Giovannelli 23 Left panel: accretion in X-ray binary systems disk-fed and wind-fed (Giovannelli & Sabau- Horne (1985) and Marsh & Horne (1988) developed Doppler tomography as a technique aimed The fast Fourier Transform (FFT) in one, two, or three dimensions is an efficient algorithm In binary systems there are essentially two ways for accreting matter from one star to the at constructing a two-dimensional velocity imagean (tomogram) emission line of in the its accretion spectra disksolutionized sampled of at the CVs a interpretation using number of of orbitally orbital phase-resolvedbinary phases. spectroscopic systems. Doppler observations It tomography of has has interacting become rev- aand valuable other tool binary for systems. resolving the For distribution instancetomography of Marsh applied line (2001) to emission in CVs. in his CVs Outstanding review discussed successes the to results that of date Doppler are the discovery of two-arm spiral well known for decades (see Cooleyrious & numerical Tukey, library. 1965) Three-dimensional as (3D) well FFT ascommunication-intensive happens components a to in traditional applications be component from one of a of any rangelence, the se- of molecular most fields dynamics, compute- (for and 3D example, tomography, in and turbu- excellent astrophysics), parallel and implementations for this in reasonsoftware existence there package today. are called many P3DFFT Pekurovsky which implementsand (2012) FFT scalable introduced in way. three a dimensions This popular inhelps paper a guide discussed highly the P3DFFT user efficient implementation in making and optimal performance choices in for a parameters of way their that runs. 5.2 Doppler tomography of accretion disks other: via accretion diskBlumenthal or & via Tucker, 1974) stellar (left windis panel (Giovannelli of a & Fig mixture Sabau-Graziati, 19). between 2001, But thepassage adapted in where two, from a some as temporary cases for accretion there disk instance& is can Ziółkowski in a (1990), be eccentric like third formed shown way binary around in the which the systemsafter right neutron close panel Nagase, star of 1989). to (e.g. Fig. the Giovannelli 19 (Giovannelli periastron & Sabau-Graziati, 2001, Figure 19: Graziati, 2001, adapted fromSabau-Graziati, Blumenthal 2001, after & Nagase, Tucker, 1989). 1974). Right panel: mixed transfer (Giovannelli & Accretion Processes in Astrophysics 5.1 Accretion driven X-ray sources PoS(APCS2016)001 and 1 Franco Giovannelli G) are not formed 7 24 G) the flow structure in the vicinity of the accretor of a CV was 5 ejk/doptomog/main.html. ∼ G), Accretion disks in such magnetic systems systems (B = 10 5 G) the flow structure can differ sufficiently from that of systems with moderate magnetic 7 Doppler tomography is very useful also for analyzing the asymmetric MHD outflows/jets from Kotze, Potter & McBride (2015, 2016) explored inside-out Doppler tomographyDoppler for tomography non- has been applied also to fusion plasmas giving an image of the fast- Zhilkin & Bisikalo (2011) presented a 3D numerical model to simulate plasma flows in close Bisikalo et al. (2008) discussed Dopppler tomography of the CV SS Cygni in quiescence. Zhilkin & Bisikalo (2009) described a 3D numerical code designed for simulations of magneto- Bisikalo & Zhilkin (2012) discussed the Flow Structure in Magnetic CVs by studying the and the flow is collimated into the accretion stream starting from the inner Lagrange point L magnetic and magnetic cataclysmichttp://www.saao.ac.za/ variables, respectively. The code they usedion is velocity available distribution at function ininteresting the to tokamak note that ASDEX Bisikalo Upgradespectrum et (Salewski of al. et turbulence from al., (2016) observations 2015). presented ofdisks. a optically It thin method Within is emission that this lines canresolution formed method, be of in used they the astrophysical to instrument, analyze recover used how the of for line the the observations. intensity power The fluctuations spectrum methodturbulence depend of allows scale. on us velocity to the turbulent restore angular pulsations the slope and estimate the upper boundary of the binary systems with accretorsassumption having that strong plasma proper dynamics magnetic ispropagating fields. determined MHD by waves. The a Equations model slowof describing average is the flow the based corresponding against slow on averaging a plasma procedure. an background motionwhich The of are is model due obtained takes to as into the a accountturbulence. current result the They dissipation presented magnetic results in diffusivity of turbulent the vortexes,Results simulations magnetic of for buoyancy MHD the flows and simulations in wave show a MHD (B that polar-like = in binary 10 system. semi-detached binary systemsfields with (B strong = magnetic 10 fields finishing on the magneticpolars. poles of the accretor. This flow structure corresponds to the case of Boneva et al. (2009) discussed theKononov Doppler et mapping al. in the (2012) case used of DopplerCygni. SS tomography Cygni for in studying outburst the and pre-outburst finally accretion disk of SS hydrodynamical (MHD) flows in semidetached binarymoderate systems. magnetic field They (B found = that 10 drastically even changed in and case the of funnel a flows were formed in the system. physical processes which go on inUsing magnetic results CVs of with 3D the MHD massaccretion simulations, transfer disks between they depending the investigated on components. variations the ofstar. value Zhilkin, the of Bisikalo main & the characteristics Mason magnetic of (2012)structure induction discussed in on on magnetic "Full the cataclysmic 3D variables surface MHD with of calculations strong, of the complex accretion accreting magnetic flow fields". Accretion Processes in Astrophysics shocks in cataclysmic variable accretion disksaction and the in probing magnetic of cataclysmic the stream/magnetospheric variablethe inter- stars. stream/disk interaction in Doppler non-magnetic tomography systemssystems. has and also the irradiation told of us the much secondary star about in all PoS(APCS2016)001 Franco Giovannelli dipole magnetosphere. ◦ 30 = Θ 25 Magnetospheric accretions in a stable (left panel) and an unstable (right panel) regime. The Romanova et al. (2014) reviewed axisymmetric and 3D MHD numerical simulations of mag- Finally, we would like to remark the importance of the Doppler tomography even in plane- Lovelace & Romanova (2014) presented results of global 3D MHD simulations of warp and netospheric accretion, plasma-field interaction andary. outflows It from is the impressive disk-magnetosphere to look bound- at the results discussed in thattary paper. science. Indeed, for instance,structure Bisikalo, in Kaygorodov systems & consisting Ionov of (2013) aproblems star investigated in modern on and astronomy. the orbiting In exoplanet. flow particular they Thisof presented is the gas results dynamics one of in of the the the numerical WASP-12 simulations system, most which interesting was observed by the Hubble Space Telescope. The density waves in accretion disks excitedFigure by 21 a shows rotating a star warp with driven a by misaligned the dipole rotating magnetic and field. tilted at Figure 20: background colours show the volume renderingThe of sample the magnetic field density lines (in are logarithmic shown scales as and red in lines arbitrary (adopted units). from Kurosawa & Romanova, 2013). Accretion Processes in Astrophysics accreting T Tauri stars. Indeed, observations ofric jets outflows from from young stellar some objects sources.drodynamic reveal the simulations asymmet- Dyda for et axisymmetric al. viscous/diffusivestars disk for accretion (2015) the to carried purpose rotating out of magnetized assessingequatorial a the plane. large conditions set where Their of the simulations outflows 2.5Doutflows are reproduce of magnetohy- asymmetric T some relative Tauri key to stars. the featuresof As of variability well observations is known, of possibly CTTSs asymmetric connectedstability are with variable that the in occurs accretion different at time-scales. ofthis the matter One regime, interface through type matter between the accretes an Rayleigh-Taylorappear in in- accretion in several random disk temporarily locations, and formed and aRomanova accretion produce (2013) stellar stochastic streams used photometric magnetosphere. or the and ’tongues’ line results In in which variability. of both Kurosawa global & stable three-dimensional and MHD unstable simulationsThey accretion of performed regimes matter a to flows similar calculate modelingand time-dependent for found hydrogen a good line agreement star profiles. between withet the realistic al., model stellar 2012). and parameters the This (i.e. time examplefer series V2129 showed (3D+3D) observed that Oph), models line the is profiles combination (Alencar aExamples of useful of the diagnostic the 3D tool magnetospheric MHD accretion for and flowsFig. studying 3D in 20. magnetospheric radiative both accretion trans- stable processes. and unstable regimes are shown in PoS(APCS2016)001 2 and L 1 Franco Giovannelli are also shown (Bisikalo et 2 dipole magnetosphere (adopted ◦ 30 and L = 1 Θ 26 (adopted from Bisikalo et al., 2013). 2 Example of a warp driven by the rotating and tilted at Density distribution and velocity vectors in the envelope of WASP-12b. The planet is depicted by and L 1 Historically, CVs – close binary systems consisting of a hot WD and red main sequence star 5.3 Accretion onto white dwarfs Figure 22: the filled circle and moves counterclockwise.of The the solid stellar yellow wind. lines denotepoints The the L flow white lines solid starting lines in denote the the gas Roche equipotentials passing through the Lagrangian from Lovelace & Romanova, 2014). Figure 21: supersonic motion of the planet insidea the complex stellar shape. wind The leads existence to of the the formation of bow a shock bow slows shock down with the outflow through the L Accretion Processes in Astrophysics points, allowing us to considermorphology a of long-living the flow flow structure is that shown inin is Fig. in the 22, the planet’s indicating steady envelope. the state. density TheThe distribution The and planet solid velocity general is yellow vectors lines depicted denote bylobe, the the depicted flow filled by lines the circle white starting and solid from moves line, the and counterclockwise. Lagrangian gas points of L the stellar wind. The Roche al., 2013). PoS(APCS2016)001 8 5 10 10 − ≈ 7 10 ≈ vs log y) appears Franco Giovannelli G). If B spin 8 10 − 6 10 ≈ Dissecting accretion and outflows in G, the accretion disk is not entirely disrupted, but 27 7 10 − 6 10 ≈ is reported by de Martino et al. (2015). The position of several polars and IPs in Lipunov’s diagram. Figure 23: Therefore, the role of magnetic field intensity plays a fundamental role in the process of ac- At the WD poles a stand-off shock is formed. The post-shock accretion column is thought According to strength of WD magnetic field this matter is creating an accretion disk (B This classification, however, is neither self-consistent nor adequate and it is much better to as the best way for localizing the position of MWDs, both polars and IPs, as shown in Fig. 23. simply truncated in its inneralong the part, magnetic and field the lines (Intermediate accretion polars). flow is also channeled onto the WD surface G, an accretion flow ismagnetic directly field channeled lines down (polars). towards the If magnetic B poles of the WD along the accreting white dwarf binaries cretion of matter onto the compact star. Therefore Lipunov’s diagram (log P to cool via bremstrahlungrelative (hard proportion X-rays), of these recombination cooling processes mechanismscher and strongly & depends cyclotron Beuermann on radiation. 2001). the WD The An magnetic field interesting (Fis- discussion about G) or follows magnetic field lines and falls to surface of the WD (B consider primarily the observed accretiondependent on behaviour the (Smak, WD 1985). magnetic field The intensity. accretion behaviour are Accretion Processes in Astrophysics of spectral type M orvicinity K, of which the fills WD the – volume classification ofdistinguish was its four based inner on groups: the Roche (i) optical lobe outburst classicalobjects. and properties, transfers novae; by matter (ii) which to one recurrent the may novae; (iii) dwarf novae; (iv) nova-like PoS(APCS2016)001 8 of − (5.2) 10 mag ≈ V ∆ Franco Giovannelli 8 days; = viscosity , and ≃ α th τ ) increases due to the appearance K; x 4 10 / 0 15 / T 8 days (GBK13); 15 is the time between the optical and X-ray 28 / ) of the 8-day delayed flare was produced. ) 1 = X ≃ τ 4 ˙ 4 m T 3 T ( / and NOT vice versa! exp 2 5 τ / 4 m 28 α 9 . Effect 6 = τ /yr) ; ⊙ M 8 − generates an ˙ ˙ M/(10 M increases (depending on the activity of the Be star) between Cause = . The outer part of the accretion disk becomes hotter, therefore the optical ˙ 1 m − . The yr ) increases. Due to large turbulent viscosity, the wave of the large mass flux is ⊙ opt M ; 7 ⊙ − 10 X-ray/Be system A0535+26/HDE245770: It is right to remind that the mechanism proposed by GBK13 for explaining the X-ray-optical Briefly, the model based on an accretion disk geometrically thin and optically thick without Time-lag between HE events and LE events in disk-fed accreting X-ray binaries (XRBs) has X-ray/Be systems are formed by a compact star and an optical star. Obviously there is a mutual ≈ • = maximum temperature in optics. 0 the optical star at the periastron and X-ray intensity (I By using this formula it istheoretical possible delays to found obtain in: an excellent agreement between the experimental and where: m = M/M flashes appearance. delay in A 0535+26/HDE 245770 iscous based accretion on disk. an This enhanced mechanism, mass knownrespect flux as to UV-optical propagation the delay optical through (the flash) the delay was vis- observed ofLasota, and the modeled 2001). EUV for flash Time cataclysmic variables with delays (e.g. have Smak, beenis 1984b; detected the also reason in that several urged other Bisnovatyi-Koganmodel, X-ray & developed transient Giovannelli for (2017) binaries. the to This particular generalizemodel the case provides aforementioned of the formula A (1) 0535+26/HDE of 245770 the (Flavia’ time star). delay in This transient cosmic general accreting sources: advection (Shakura & Sunyaev, 1973; Bisnovatyi-Kogan, 2002)periastron is the the mass following: flux in theand vicinity of been noted in many systems, but the triggersuch of a the phenomenon work resulted (Bisnovatyi-Kogan in & a Giovannelli, modelGraziati 2017) for (2011) explaining was in who given general by noted Giovannelli athe & systematic optical Sabau- delay Be between star the – relativeX-ray occurring enhancement flare at in in the luminosity the periastron of systemand passage HDE corroborated of 245770/A by the 0535+26. many events neutron (Giovannelli, The starlater Bisnovatyi-Kogan model & – by Klepnev, for and 2013: events such the GBK13), reported a and subsequent in system Giovannelli was et developed al. (2015) where also a relationship between luminosity (L influence between the two stars. Low-energyand (LE) processes vice influence versa. high-energy (HE) Never processes Cause confuse and the Effect effect with the cause. There is a general law in the Universe: propagating toward the neutron star, thus the X-ray luminosity (L Accretion Processes in Astrophysics 5.4 Accretion onto neutron stars of a hot accretion disk regionmagnetic and due poles the of accretion flow the channeled neutron by the star. magnetic field The lines time–delay onto T PoS(APCS2016)001 ≃ th τ 6.5 days. ≃ th τ Franco Giovannelli 3 days (Shahbaz et al., 1998); ∼ 6 days (Orosz et al., 1997); exp , taking into account the experimental delay ∼ τ α exp τ 29 = 0.9–1.4 days (Wheatley, Mauche & Mattei, 2003); exp τ 0.1, independent of the accretion rate. The model has been -viscosity parameter plays an important role, and usually it is ∼ α 1.35 days; Time-lag general model for disk-fed accreting XRBs (Bisnovatyi-Kogan & Giovannelli, 2017). ≃ th Black hole X-ray transient GRO J1655-40: Cataclysmic variable SS Cygni; τ Low-mass X-ray binary Aql X-1/V1333 Aql: 3.2days Recently several books about black holes appeared in the literature: As already noted black hole accretion is a fundamental physical process in the universe. It is This general model for the time-lag for disk-fed accreting XRBs is sketched in Fig. 24. In this general formula the • • • Figure 24: successfully applied to luminous sources suchthe as thermal luminous AGNs state. and black The holeLasota most X-ray (2016). recent binaries review in about the accretion onto black holes was published by 5.5 Accretion onto black holes the standard model for the centralrole engine of in active galactic the nuclei study (AGNs),According and of to also the plays black a temperature hole central ofclasses, X-ray the namely accretion binaries, cold flow, Gamma-ray the and accretion bursts,temperature hot. models of and can The the tidal be gas standard divided disruption into is(Pringle, thin events. two far disk 1981; below model Frank, the belongs King virialdisk to & is value the Rayne, geometrically (Shakura cold thin 2002; & but disk, Sunyaev, Abramowicz opticallyThe since 1973) thick & radiative the and (see Fragile, efficiency radiates reviews is 2013; multi-temperature by black high, Blaes, body 2014). spectrum. The hard to be determined. However, ifmined, the the other formula parameters (5.2) are can known, be because used for experimentally determining deter- Accretion Processes in Astrophysics measured in a certain source. PoS(APCS2016)001 Tran- , Franco Giovannelli Winds from Black Hole , A Brief Review of Relativistic , . Black Hole Accretion Discs (Bambi, 2017a). The main aim of (Contopoulos, Gabuzda & Kylafis, 2015). (Beskin et al. 2015). The topic of this volume (Falanga et al., 2015). It provides a comprehen- 30 (Bambi, 2016). This book contains the most relevant papers General Relativity in a Nutshell Black Hole Spin: Theory and Observation , , and Black Holes: A Laboratory for Testing Strong Gravity Astrophysics of Black Holes discussed during the FudanUniversity, Winter in Shanghai, School from on February Astrophysical 10sient Black to Black Hole 15, Binaries Holes 2014): (heldAccretion at Flows: Fudan Formation and Their Interaction with ISM this book is toaround discuss astrophysical black the holes. For electromagnetic completeness,reviewed, techniques gravitational wave but to methods will only study be very also thecorresponding briefly strong line and of gravity research. without region the Thisthis book necessary research has field. details not Hopefully, the to it ambition may start to be working a be good a on starting complete the point. manual on contains reviews of completely new aspects ofThe magnetic strength fields in of the the astrophysicalto Universe. magnetic 8 fields to of 10 the ordersfields compact of in magnitude objects the higher solar reviewed system. than ingalactic that Large-scale this fields astrophysical of are volume magnetic typical weaker fields, is sunspots still such up than which as the are interstellar fields the and experiencedThe strongest in Formation the and solar Disruption system. of Black Hole Jets The Physics of Accretion onto Blacksive summary Holes on the physical modelsmergers, and in current both theory the of black supermassive and hole stellar-mass accretion, cases. growth and The Strongest Magnetic Fields in the Universe The main aim of this bookradio to is X-ray to spectra present of reviews stellar ofscales binaries the through and varied the which phenomenology properties they regarding of propagate, the AGNphysical as jets mechanisms on well that the as contribute wide recent to range theoretical of theemphasis is origin efforts given of to to the black understand role hole the andfields jets the origin on that of all the drive, scales. black collimate, hole Particular magnetospherea and and the consistent, accelerate magnetic the unified jets. physicalblack picture hole The systems. of final New the observational goal andcontents formation is theoretical of results and a this are disruption tentative piling volume up of of only everypresent giving represent jets day, understanding so our is in the current to accreting reality. best ideas. Time will tell how close our Gravitational Collapse Important news were reported over the last couple of decades. We have witnessed the dis- Black hole hot accretion flows occur in the regime of relatively low accretion rates and are • • • • • covery of a multitude ofand highly NS ionized XRBs. absorbers The in first detections high-resolution40 were X-ray and obtained spectra thanks GRS from to 1915+105. both ASCA onXXV BH Narrow the and absorption BH Fe lines binaries GROJ1655- XXVI in indicated the(Chandra, XMM-Newton the spectra and first of Suzaku). of these many systems discoveries identified of as photo-ionized Fe plasmasoperating in in LMXBs the nuclei of most of the galaxies in the universe. One of the most important progress Accretion Processes in Astrophysics PoS(APCS2016)001 (5.3) is the 2 neutrino , The Scientific = 2GM/c Franco Giovannelli s photonic astrophysics (Prusti et al., 2016). Gaia Collab- 1 s − ) s 10% accuracy in determining the stellar 20r / ∼ r sources brighter than magnitude 20.7 in the 1 km s ( 9 ∼ BH 10 ˙ " (Gardner & the JWST Science Working Group, M 31 > Gaia Data Release 1: Summary of the astrometric, ) = r ( . The synergy of these methods converge in what we call wind ˙ M . . is the mass accretion rate at the black hole horizon and r BH ˙ particle astrophysics M -ray sources. With the advent of the European–Extreme Large Telescope: E–ELT γ , and 1, and ≈ astroparticle physics Another important jump in the knowledge of our Universe will come from the James Webb GAIA (e.g. Rix & Bovy, 2013), the new generation astrometric satellite after HIPPARCOS, With the sensitivity of the Cherenkov Telescope Array (CTA) we expect the detection of thou- It is evident that the future of the research in astrophysics must take into account the three Experiments distances and stellar velocities withoration resolution (Brown of et al.,photometric, 2016) and published survey properties the " 2009), and numerous other white papers exploring different scientific topics at: white-light of its photometric bandcalibrating G. the Gaia is energetic providing of strong cosmic impact sources on thanks stellar to evolution and in Capabilities of the James Webb Space Telescope Space Telescope (JWST) thatleap will forward in be our launchedery quest in phase to orbit of understand in cosmic thefirst history, Universe 2018. luminous and namely glows our the The after origins. Bridgeevolution JWST the between of JWST Big will the our will Bang be Big own examineof to Bang a solar ev- exoplanets, the and system. giant and formation Biology: perhaps of Moreover,http://jwst.nasa.gov/science.html). from even galaxies, JWST the find stars, For will the details tell and building about us planets blocks JWST more to of see about the life the the elsewhere white atmospheres in papers the " universe (see now was launched at the end ofpositions, 2013 to parallaxes, collect and data that proper will motions allow for the determination of highly accurate astrophysics sands VHE main methods to tackle the way of the knowledge of our Universe: 6. Prospects for the Astrophysics of Next Decades: the Contribution of Small where s Accretion Processes in Astrophysics in recent years in thisrapid field development is of about the numerical wind simulationse.g., or of Sgr outflow. accretion A*, This flows, the progress supermassive combinedwind is black can with mainly be hole attributed observations described in to on, by: the the Galactic center (Yuan, 2016). The mass flux of Schwarzschild radius. we will be witnesses of astonishingpriorities in results. ground-based E–ELT astronomy. is It will considered vastlynear worldwide advance as infrared astrophysical one knowledge (NIR) in of optical regions, the and allowing highest stars, detailed the first studies objects of in the subjectsthe Universe, including dark super-massive black planets matter holes, and around and dark the other energy nature which and dominate distribution the of Universe. PoS(APCS2016)001 Franco Giovannelli 32 m to study the properties of galaxies at very high µ 7 (Yonetoku et al., 2014). Small space missions, complementary > As discussed by Giovannelli & Sabau-Graziati (2016) in section 3.7 of their paper, how reion- It is important to remark the contribution to science provided by: i) Robotic Autonomous Ob- Probably the best example of the importance of small missions is the joint JAXA/NASA An interesting example of a micro-satellite developed by the students of Tokyo Institute of https://jwst.stsci.edu/science/science-corner/white-papers. Together with such impressive big experiments it is necessary to mention the extreme im- ization occurred is still anfield open Imaging problem that Surveyor deserves for particular High-redshifts)widefield attention. is surveys Indeed, a at WISH space NIR (Wide- mission wavelength at concept 1–5 to conduct very deep and servatories (Castro-Tirado, 2010); ii) Global(GLORIA) Robotic (Castro-Tirado Telescopes et Intelligent al., Array 2014, for E-Science 2015); iii) (B)urst (O)bserver and (O)ptical (T)ransient ASTRO-H mission, the sixthInstitute in of Space a and series Astronautical Science ofThe (ISAS) launch (e.g. highly date Takahashi, successful den was Herder decided X-ray & tothrough Bautz missions be , on results developed 2014a). February in by 12, scientific 2016. the evolution, ASTRO-H areas the is as expected behaviour to of diverse provide matter as break- inin the sites the of gravitational large-scale cosmic-ray strong acceleration, structure field and of theredshifts regime, distribution (Takahashi the the of et physical dark Universe al., matter conditions and 2014b in galaxy – its the clusters ASTRO-H series at Space of different X-ray white Observatory: papers, dedicated White to Paper the – different in topics, which is listed). Technology is TSUBAME (launched from Russialarization on of GRBs Nov in 6, order 2014) toexample for reveal about measuring the the hard nature complementarity X-ray of of po- theirExoplanet small central Survey mission engine Satellite). to (Kurita big It et experiments al., willa is 2015). search next TESS for Other (The logical planets Transiting step transiting aftervealing bright that and NASA’s Kepler planets nearby mission with stars. that sizesal., TESS revolutionized between 2011; is exoplanetary those Fressin science of et al., the by 2013).physics Earth re- Explorer and TESS mission. has Neptune The been are longest selected abundantwhich observing by (Borucki are intervals NASA et for will the launch be optimal in for locationsfind 2017 stars for more as near an than the follow-up Astro- ecliptic a observations poles, thousand withsize planets the to smaller JWST. the than TESS Earth Neptune, is (Ricker includingHiZ-GUNDAM et expected dozens for al., to that 2015). future are comparable One observations example in dark of more ages GRBs. is and the the The study dawn ofuniverse of mission beyond a formation concept the small of redshift is satellite astronomical z objects", mission to i.e. probe the "the physical end condition of of early portance of small experimentsof that investigations constitute not useful possible and withi) indispensable the space-based tools experiments: larger for ones small–, a forments: mini–, huge small a micro– telescopes number great and and number robotic nano–satellites; telescopes. of ii) reasons. ground-based experi- They can be: Accretion Processes in Astrophysics to those Earth–based, even larger, are alsolike devoted for to instance investigate the cosmic NUCLEON rays space at experimentsphere, very designed the high to energy energies, investigate spectra directly, of above the cosmic-ray atmo- range nuclei and 100 the GeV chemical – composition (Z 1000experiment = TeV, on 1–30) including at board the energy of "knee" the energy RESURS-P satellite range was (Atkin launched et on al., December 26, 2015). 2014. NUCLEON redshift beyond the epoch of cosmic reionization (Yamada et al., 2012). PoS(APCS2016)001 - α Franco Giovannelli 33 After this long discussion we hope to have stressed sufficiently that the accretion processes It appears also evident the importance of multi-frequency astrophysics from ground– and With the addition of the SAAO Telescope "farm" on the Sutherland plateau, MASTER-SAAO are fundamental for explaining the physicsclearly of learned the is vast majority that of the astrophysical most objects. critical What parameter we for studying the accretion processes is the space–based experiments in order to deeply explore the nature of our Universe. 7. Conclusions is giving a massive contribution toof transient cosmic alerts sources, in such Astronomer’s asetc. telegrams GRBs, for (e.g at different SNe, August classes Blazars, 2015, Novae, 530 X-ray new CVs pulsars, have CVs, been discovered) fast (Buckley, rapid 2015). transient viscosity – very difficult to beaccretor, measured the –, diameter in of spite the of accretion all disk, other the parameters, size such and as composition of the dust mass and of grains, the etc. Accretion Processes in Astrophysics (E)xploring (S)ystem (BOOTES) (Castro-Tiradotelescope et of al., the 2012). BOOTESmonitoring With worldwide of the astronomical network targets installation of (Hiriart, of 2014); roboticdesigned iv) the Pi telescopes for of fifth observations it the Sky of is (a shortemissions) system possible timescale of (Siudek robotic a astrophysical et telescopes al., phenomena, continuous 2011). e.g. PIal., of prompt 2014; the optical Obara Sky GRB et is now al.,strous part 2014); Explosions). of v) the MITSuME MITSuME(Multicolor GLORIA system telescopes Imaging (Mankiewiczfollow-up were Telescope et observations for designed for Survey to gamma-ray and bursts perform Mon- (GRBs) "real(Shimokawabe prompted et time" by al., and 2008). the "automatic" GCN An example alerts of viais follow-up briefly the observations reported for internet GRBs by and Saito black et hole al.a binary (2012, project 2014); began vi) in CHASE (CHilean 2007 Automatici) with Supernova better the sEarch) understand goal the to physics discoverderive of young, extragalactic exploding distances. nearby stars During southern the and supernovae first in theirthan four order progenitors; 130 years supernovae to: ii) of (Hamuy operation, refine et CHASE the al., hasproject, 2012); methods produced whose vii) to more purpose MUSICOS is (MUlti-SIte to COntinuous organize Spectroscopy) multisiteBöhm, continuous 1992; spectroscopic Foing observations et (Baudrand al., & 1992); viii)born WET (Whole in Earth Telescope) 1986 (Nather et when al., scientistsworld-wide 1990). network from The of idea the cooperating University astronomical of observatoriesmeasurements to Texas of obtain Astronomy variable uninterrupted Department stars. time-series established Thisfledgling a approach science has of been stellar extremely seismology successful,1996; at and Kilkenny the et has al., forefront placed 2003; of the Reed stellarTElescope-Robots). et astrophysics al., (e.g. The 2011); ix) main Handler MASTER goal et (Mobilesurvey of Astronomical with al., all System the sky of MASTER-Net observed the over project avey single is will night to make down to it produce a possible a limiting to magnitude unique addressthe of a discovery fast 19–20. and number Such sky photometry of a of fundamental sur- supernovae problems: (includingeffects, search SNIa), discovery for search of dark for minor energy exoplanets, via bodies microlensing intelescopes the can Solar be System, guided and by space-junkGRBs monitoring. alerts, synchronously in and All several MASTER realize filters the andalso observations in http://observ.pereplet.ru/MASTER(underscore)OT.html). of several polarization prompt planes optical (Lipunov emission et al., from 2010; see PoS(APCS2016)001 Franco Giovannelli ) ∗ ( is really a universal phenomenon, like shown in 34 accretion Accretion is a universal phenomenon (courtesy of Jaime Sanchez Calleja, 2016). Figure 25: We hope also to have caused the curiosity of the reader about the investigations for discovering Thus, finally we can conclude that And for the ground–based small experiments we have mentioned the small telescopes (SmTs) When we discussed the prospects for the astrophysics of next decades, we hope to have given life or signs of lifescientific on field other – planets. not only Indeed,key focused the on environmental Astrobiology the parameters – search that a of havegeneral extraterrestrial recently enabled sense life, born the the but interdisciplinary result emergence also of of accretion on processes deciphering life originated the on in the Earth, protoplanetary which disk around isFig. the just Sun. 25 in (courtesy of Jaime Sanchez Calleja, 2016). – including those belong to amateurs –of that selected are sources, the unique usually capable forbidden ofand doing with grouped long–term larger observations in telescopes. specific programs SmTsprovide (e.g. – continuous spread long-term WET, monitor along MUSICOS, of the BOOTES, selected longitude GLORIA,stars sources for MASTER) without stellar – night–day seismology, RS interruption can CVn (i.e. stars,– sdB XRBs, better CVs, if GRBs, robotic survey – of are asteroids,...).space–based unreplaceable tools Thus, multi-frequency complementary SmTs experiments. to larger telescopes and to ground– and enough arguments in favor of smallof experiments, large of experiments, course especially not those rejecting looking theample at extremely of the importance small first space–based stages of experimentsTSUBAME the dedicated for life to measuring of hard specific our X-ray investigations, Universe. polarization webright of As have GRBs, and ex- mentioned TESS nearby for stars, searching HiZ-GUNDAM planetstion for transiting probing of the astronomical end objects, ofbeyond WISH dark the ages for epoch and studying of the cosmic the dawn reionization,of properties of NUCLEON cosmic-ray of forma- nuclei for and galaxies investigating their directly at chemical the composition,will very energy and provide spectra high ASTRO-H, breakthrough that, redshift results in in spite many of different its scientific small size, areas. Accretion Processes in Astrophysics PoS(APCS2016)001 , The . , Living Franco Giovannelli , PhRvD 95, Issue 10, , arXiv 171110256. , Springer Nature Singapore , P. Eggleton, S. Mitton & J. Disks, Jets and the dawn of planets 35 Foundations of Black Hole Accretion Disk Theory , Montmerle Th., Lada C.J., Mirabel, I.F. & Trân Thanh Vân, J. Astrophysics of Black Holes: From Fundamental Aspects to Latest Structure and Evolution of Close Binary Systems The Cold Universe Testing black hole candidates with electromagnetic radiation Black Holes: A Laboratory for Testing Strong Gravity Astrophysical Black Holes: A Compact Pedagogical Review This research has made use of: , Astrophysics and Space Science Library, Volume 440, 207 pp. The NASA’s Astrophysics Data System; the NASA Exoplanet Archive, whichunder is contract operated with by the National the Aeronautics CaliforniaExploration and Institute Program; Space of Administration under Technology, the Exoplanet Whelan (Eds.), D. Reidel Publishing Co., IAU Symp. 73, p. 173. Bath, G.T.: 1976, in Bath, G.T.: 1969, ApJ 158, 571. Bath, G.T.: 1975, MNRAS 171, 311. Rev. Relativity 16, 1-88. eprint arXiv:1506.07073. Bambi, C. (Ed.): 2016, Bambi, C.: 2017a, Pte Ltd., ISBN 978-981-10-4523-3, 340 pp. Bambi, C.: 2017b, id. 104035. Bambi, C.: 2017c, Atkin, E., Bulatov, V., Dorokhov, V., Gorbunov, N.,Volume Filippov, 105, S. id.01002. et al.: 2015, EPJ Web of Conferences, Developments Alencar, S.H.P., Bouvier, J., Walter, F.M., Dougados,A116, C., 14 Donati, pp. J.-F. et al.: 2012, A&A 541,André, id. P., 1994: in (Eds), Editions Frontières, Paris, p. 179. Antoniucci, S., Alcalá, J.M., Codella, C., Nisini, B. (Eds.): 2015, Arquilla, R., Goldsmith, P.F.: 1986, ApJ 303, 356-374. Adams, F.C., Shu, F.H.: 1986, ApJ 308. 836. Adams, F.C., Emerson, J.P., Fuller, G.A.: 1990, ApJ 357, 606-620. Abramowicz, M.A., Fragile, P.C.: 2013, Adams, F.C.: 1988, PhD Thesis, California Univ., Berkeley, USA. • • Unfortunately, during the time of the editing this review, JAXA (Japan Aerospace Exploration Agency) experienced ) [6] [7] [8] [9] [4] [5] [1] [2] [3] ∗ [14] [15] [16] [12] [13] [10] [11] References Acknowledgments Accretion Processes in Astrophysics ( on March 27, 2016 (JST) a communicationJapan Aerospace anomaly Exploration with Agency (JAXA) the found of that communication X-ray with Astronomy "Hitomi"launched Satellite (ASTRO-H) on failed. "Hitomi" February The (ASTRO-H): 17, "Hitomi", 2016 (JST),Saturday failed March from 26 (JST). the Up start to of now, its JAXA has operation, not which been was able originally to figure scheduled out at the 16:40, state of health of the satellite PoS(APCS2016)001 , Protostars , PhD Thesis, the Franco Giovannelli , Dordrecht, D. Reidel , Charles J. Lada & Nikolaos , Proc. of the Sixth APCTP Winter Numerical Modeling of Space Plasma Flows , Space Sciences Series of ISSI, Vol. 54, Springer 36 From Interacting Binaries to Exoplanets: Essential Modeling The Physics of Star Formation & Early Stellar Evolution Black Hole Astrophysics 2002 The Origin of Stars and Planetary Systems Close binary stars: Observations and interpretation , N.V. Pogorelov, E. Audit & G.P. Zank (Eds.), ASP Conf. Ser. 474, 41-46. The Evolution of Gas and Dust in Protoplanetary Accretion Disks , 951 pp., V.B. Reipurth, D. Jewitt & K. Keil (Eds.), University of Arizona Press, Tucson, The Strongest Magnetic Fields in the Universe , M.T. Richards & I. Hubeny (Eds.), IAU Symp. 282, 509-516. Borucki, W.J., Koch, D.G., Basri, G., Batalha, N., Brown,Bouvier, T.M. J., et Alencar, al.: S.H.P., Harries, 2011, T.J., ApJ, Johns-Krull, 736, C.M., 19. Romanova, M.M.: 2007, in Tools Bisikalo, D.V., Kurbatov, E.P., Pavlyuchenkov, Ya.N., Zhilkin, A.G.,MNRAS Kaygorodov, 458, P.V.: 2016, 3892-3903. Bisnovatyi-Kogan, G.S.: 2002, in Schoo, Pohang, Korea, pp. 187-206. Bisnovatyi-Kogan, G.S., Giovannelli, F.: 2017, A&A 599, id. A55,Blumenthal, 7 G.R., pp. Tucker, W.H.: 1974, Ann. Rev. A&A 12,Boneva, 23-46. D., Kaigorodov, P.V., Bisikalo, D.V., Kononov, D.A.: 2009, ARep 53, 1004-1012. and Planets 479-494. Bisikalo, D., Kaygorodov, P., Ionov, D., Shematovich,article V., id. Lammer, H., 19, Fossati, 5 L.: pp. 2013, ApJ 764, Bisikalo, D.V., Kononov, D.A., Kaigorodov, P.V., Zhilkin, A.G.,318-326. Boyarchuk, A.A.: 2008, ARep 52, Bisikalo, D.V., Zhilkin, A.G.: 2012, in Bisikalo, D.V., Kaygorodov, P.V., Ionov, D.E.: 2013, in Birnstiel, T.: 2010, Publishing Co., IAU Symp. 88, 155-160. Beckwith, S.V.W.: 1998, talk at the NATO/ASI, Crete II, 3 June. Beckwith, S.V.W.: 1999, in D. Kylafis (Eds.), Kluwer Academic Publishers, p. 579. Beckwith, S.V.W., Sargent, A.I., Chini, R.S., Güsten, R.: 1990,Beckwith, AJ S.V.W., Sargent, 99, A.I.: 924-945. 1991, ApJ 381, 250-258. Beskin, V.S., Balogh, A., Falanga, M.,2015, Lyutikov, M., Mereghetti, S., Piran, T., Treumann, R.A. (Eds.): Ruperto-Carola University of Heidelberg, Germany. arXiv:1107.3466v1 [astro-ph.EP] 18 Jul 2011. (ASTRONUM2012) Baudrand, J., Böhm, T.: 1992, A&A, 259, 711. Beall, J.H., Knight, F.K., Smith, H.A., Wood, K.S., Lebofsky, M., Rieke, G.: 1984, ApJ 284, 745-750. Bath, G.T.: 1978, Q. Jl R. astr. Soc.Bath, 19, G.T.: 442. 1980, in Bath, G.T.: 1984a, Physica Scripta T7, 101-107. Bath, G.T.: 1984b, Ap&SS 99. 127-137. Bath, G.T., Evans, W.D., Papaloizou, J., Pringle, J.E.: 1974, MNRAS 169, 447. Science+Business Media New York, ISBN 978-1-4939-3549-9, 579 pp. [39] [40] [36] [37] [38] [33] [34] [35] [31] [32] [29] [30] [26] [27] [28] [22] [23] [24] [25] [19] [20] [21] Accretion Processes in Astrophysics [17] [18] PoS(APCS2016)001 , , Second Franco Giovannelli , Mannings, V., Boss, A.P., , Proc. of the XI Scientific The Formation and Disruption of Black Hole The Golden Age of Cataclysmic Variables and , S. Guziy, S.B. Pandey, J.C. Tello & A.J. Protostars and Planets IV 37 , New York: Macmillan, 128 pp. , J.C. Tello, A. Riva, D. Hiriart & A.J. Castro-Tirado (Eds.), Rev. An algorithm for the machine calculation of complex Fourier series Highlights of Spanish Astrophysics VIII , S.K. Chakrabarti (Ed.), Allied Publishers, p. 145, 2002. Study of Accretion Processes on Black Holes: Fifty Years of Developments ". Intelligent Life in Space Robotic Astronomy 2013 , Astrophysics and Space Science Library, Volume 414. ISBN 978-3-319-10355-6. Springer Frontiers in Astrophysics Drake, F.D.: 1962, Drouart, A., Dubrulle, B., Gautier, D., Robert, F.: 1999, Icarus 140, 129-155. Coughlin, J.L., Mullally, F., Thompson, S.E., Rowe, J.F., Burke, C.J. et al.: 2016, ApJS, 224, 12. Meeting of the Spanish Astronomical Society, A.J. Cenarro et al. (eds.), p. 895. Cooley, J.W., Tukey, J.W.: 1965, Math. Comput. 19, 297-301. Cottin, H., Kotler, J.M., Bartik, K.,209, Cleaves, 1-42. H.J., Cockell, C.S., de Vera, J.-P.P. etal.: 2017a,Cottin, SSRv H., Kotler, J.M., Billi, D.,83-181. Cockell, C., Demets, R. Ehrenfreund, P. et al.: 2017b, SSRv 209, Cohen, M.: 1983, ApJ 270, L69. Contopoulos, I., Gabuzda, D., Kylafis, N. (Eds.): 2015, Castro-Tirado (Eds.), ASI Conf. Ser., 7, 313-320. Castro-Tirado, A.J.: 2015, in Chakrabarti, S.K.: 2004, Chiang, E.I., Goldreich, P.: 1997, ApJ 490, 368-376. Cleeves L. Ilsedore et al.: 2014, Science, 345, 1590. Jets International Publishing Switzerland, 273 pp. Castro-Tirado, A.J., Sánchez Moreno, F.M., Pérez2014, del in Pulgar, C.J., Azócar, D., Beskin, G. et al.: arXiv:astro-ph/0402562v1. Related Objects - III Russell, S.S. (Eds.), (Book - Tucson: University of Arizona Press), p. 377. Caselli, P.: 2003, Ap&SS 285, 619-631. Carpenter, J.M., Bouwman, J., Mamajek, E.E.,181, Meyer, 197-226. M.R., Hillenbrand, L.A. et al.: 2009, ApJS Castro-Tirado, A.J.: 2010, Hindawi Publ. Co. Adv. inCastro-Tirado, Astron., A.J., Vol. 2010, Jelínek, ID M., 570489, Gorosabel, 8 J.,Workshop pages. Kubánek, on P., Robotic Cunniffe, Autonomous R. Observatories et al.: 2012, in Mex. A&A Conf. Ser., 45, 104-109. in Caselli, P.: 2002, Planetary and Space Science 50, 1133-1144. Bovaird, T. & Lineweaver, C.H.: 2013, MNRAS 435, 1126. Brown, A.G.A. et al. (Gaia Collaboration): 2016, A&ABuckley, 595, D.: id.A2, 2015, 23 talk pp. at the Palermo Workshop on " Burrows, C.J., Stapelfeldt, K.R., Watson, A.M.,437-451. Krist, J.E., Ballester, G.E. et al.: 1996, ApJCalvet, 473, N., Hartmann, L., Strom, S.E.: 2000, in [61] [62] [63] [59] [60] [55] [56] [57] [58] [53] [54] [51] [52] [49] [50] [45] [46] [47] [48] [43] [44] Accretion Processes in Astrophysics [41] [42] PoS(APCS2016)001 , V,B. , Cambridge , Cambridge, , Annu. Rev. The Physics of Franco Giovannelli Cool stars, stellar , Cambridge and New York, , B. Reipurth, D. Jewitt & K. Keil Protostars and Planets 38 , F. Giovannelli (ed.), President Bureau of the CNR, Protostars and Planets V High-energy processes in young stellar objects Accretion Power in Astrophysics Accretion Power in Astrophysics - Second Edition Accretion Power in Astrophysics - Third Edition , Springer, Space Sciences Series of ISSI, Vol. 49, 483 pp. The Bridge between the Big Bang and Biology (Stars, Planetary Systems, , Proc. of the 7th Cambridge Workshop, ASP Conf. Ser., 26, 637-642. Roma, Italy, p. 439. Giovannelli, F., Vittone, A.A., Rossi, C., Errico,et al.: L., Bisnovatyi-Kogan, 1995, G.S., A&AS Kurt, 114, V.G., Lamzin, 341. S.A. Atmospheres, Volcanoes: Their Link to Life) Giovannelli, F.: 2016, http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=275, id.31. Giovannelli, F., Ziółkowski, J.: 1990, Acta Astron. 40, 95. Astron. Astrophys. 37, 363-408. Cambridge University Press, 283 pp. University Press, ISBN 0-521-40306-5, pp. xvi + 294. UK: Cambridge University Press, pp. 398. ISBN 0521620538. Gardner, J.P.: 2009, Astro2010: The AstronomyPapers, and no. Astrophysics 84. Decadal Survey, Science White Giovannelli, F.: 1994, SSRv 69, 1-138. Giovannelli, F.: 2001, in Giovannelli, F.: 2008, ChJA&A 8, Suppl. 237-258. Fressin, F., Torres, G., Charbonneau, D.,id. Bryson, 81, S.T., Christiansen, 20 J. pp. et al.: 2013, ApJ, 766, article Frank, J., King, A., Raine, D.J.: 1985, Frank, J., King, A., Raine, D.J.: 1992, Frank, J., King, A., Raine, D.J.: 2002, Fischer A., Beuermann K.: 2001, A&A 373, 211. Foing, B.H., Catala, C., Baudrand, J., Boehm, T. (MUSICOS Team): 1992, in Reipurth, D. Jewitt & K. Keil (Eds.), University of Arizona Press, Tucson, 951 pp., p. 555-572. (Eds.), 951 pp., University of Arizona Press, Tucson, p. 495-506. Elmegreen, B.G.: 2002, ApJ 577, 206-220. Elsasser, H., Staude, H.J.: 1978, A&A 70, L3. Enoch, M.L., Corder, S., Dunham, M.M., Duchêne, G.:Falanga, 2009, M., ApJ Belloni, 707, T., 103-113. Casella, P., Gilfanov,Accretion M., onto Jonker, Black P., Holes King, A. (Eds.): 2015, Feigelson, E.D., Montmerle, T.: 1999, systems, and the sun Dyson, F.: 1960, Science, 131, 1667. Efremov, Y.N., Elmegreen, B.G.: 1998, MNRAS 299, 588-594. Dullemond, C.P., Hollenbach, D., Kamp, I., D’Alessio, P.: 2007, in Dutrey, A., Guilloteau, S., Duvert, G., Prato, L., Simon,Dutrey, A., M. Guilloteau, et S., al.: Ho, 1996, P.: A&A 2007, 309, in 493-504. Dyda, S., Lovelace, R.V.E., Ustyugova, G.V., Lii,MNRAS P.S., Romanova, 450, M.M., 481-493. Koldoba, A.V.: 2015, [85] [86] [87] [83] [84] [80] [81] [82] [78] [79] [75] [76] [77] [72] [73] [74] [68] [69] [70] [71] [65] [66] [67] Accretion Processes in Astrophysics [64] PoS(APCS2016)001 , IAU , ARA&A 54, Franco Giovannelli , F. Giovannelli Multifrequency Accretion Processes in , Cambridge, UK; New York: Cambridge Accretion onto Pre-Main-Sequence Stars 39 The Golden Age of Cataclysmic Variables and Related Frontier Research in Astrophysics - II , Franco Giovannelli & Lola Sabau-Graziati (Eds.), Mem. The Impact of Space Experiments on our Knowledge of the , Reprinted from Space Science Reviews, Vol. 112, Nos. 1-4, pp. 1-443 Accretion Processes in Star Formation From Interstellar Clouds to Star-Forming Galaxies: Universal Processes? , Cambridge, UK: Cambridge University Press. , F. Giovannelli & L. Sabau-Graziati (eds.), Mem. S.A.It., 83 N. 2, 698-707. Hillenbrand, L.A.: 2008, Phys. Scr. T130, id. 014024,Hiriart, 7 D.: pp. 2014, Rev. Mex. A&A Conf. Ser.,Horne, 45, K.: 87. 1985, MNRAS 213, 129-141. Illarionov, A.F., Sunyaev, R.A.: 1975, A&A 39, 185. Isella, A.: 2016, in Henning, Th., Michel, B., Stognienko, R.: 1995, P&SS 43, 1333-1343. Handler, G., Breger, M., Sullivan, D.J., van der Peet, A.J., Clemens, J.C. et al.:Hartmann, 1996, L.: A&A, 1998, 307, Hartmann, L., Kenyon, S.J.: 1987a, ApJ 312, 243-253. Hartmann, L., Kenyon, S.J.: 1987b, ApJ 322, 393-398. Hartmann, L., Herczeg, G., Calvet, N.: 2016, Han, E., Wang, S., Wright, J.T., Feng, Y.K., Zhao, M. et al.: 2014, PASP, 126, 827. Greene, T.P.: 2001, American Scientist, 89(4), 316-325. Hamuy, M., Pignata, G., Maza, J., Clocchiatti, A., Anderson, J. et al., 2012, in Behaviour of High Energy Cosmic Sources 135-180. Symp. 315, 107-113. 529-538. SAIt., 83, 388-392. University Press, (Cambridge astrophysics series; 32). ISBN 0521435072. Goodman, J.: 1993, ApJ 406, 596-613. Gorti, U., Liseau, R., Sándor, Z., Clarke, C.: 2016, SSRv 205, 125-152. Giovannelli, F., Sabau-Graziati, L.: 2016, in Giovannelli, F., Bisnovatyi-Kogan, G.S.: 2017, A&A 599, id.A55, 7González-Casanova, D.F., pp. Lazarian, A., Santos-Lima, R.: 2016, ApJGonzález 819, Martínez-País, article I., id. Shahbaz, 96, T., 11 Casares pp. Astrophysics Velázquez, J. (Eds.): 2014, (2004), Kluwer Academic Publishers, Dordrecht (GSG2004). Giovannelli F, Bisnovatyi-Kogan, G.S., Klepnev, A.S.: 2013, A&A 560,Giovannelli, A1 F., Bisnovatyi-Kogan, (GBK13). G.S., Bruni, I., Corfini,Astron. G., 65, Martinelli, 107. F., Rossi, C.: 2015, Acta Giovannelli, F., Sabau-Graziati, L.: 2001, Ap&SS, 276, 67. Giovannelli, F., Sabau-Graziati, L.: 2004, Physics of the Universe Giovannelli, F., Sabau-Graziati, L.: 2011, Acta Polytechnica, Vol. 51,Giovannelli, No. F., Sabau-Graziati, 2., L.: p. 21. 2012, in Objects (Ed.), https://pos.sissa.it/269/001/pdf. [111] [112] [113] [108] [109] [110] [104] [105] [106] [107] [102] [103] [98] [99] [100] [101] [95] [96] [97] [92] [93] [94] [90] [91] Accretion Processes in Astrophysics [88] [89] PoS(APCS2016)001 , IAU Symp. , Cambridge Franco Giovannelli , Cosimo Bambi , PhD Thesis, Milano X-ray Binaries Magnetic Fields in Diffuse Astrophysics of Black Holes , in 40 Magnetic Fields throughout Stellar Evolution Theory of Accretion Disks II: Application to Observed Black Hole Accretion Discs Interferometric observations of pre-main sequence disks , ARA&A 34, 703-747. , Astrophysics and Space Science Library, Volume 407. ISBN 978-3-662-44624-9. Lineweaver, C.H. & Chopra, A.: 2012, Ann. Rev. ofLinsky, Earth J.L., and Schöller, M.: Planetary Sci., 2015, 40 SSRv (issue 191, 1), Issue 597. 1-4,Lipunov, V.M.: 27-76. 1987, Ap&SS 132, 1. Lipunov, V.M., Postnov, K.A.: 1988, Ap&SS 145, 1. Lipunov, V., Kornilov, V., Gorbovskoy, E., Shatskij, N., Kuvshinov, D., Tyurina, N. et al.: 2010, Lineweaver, C.H., Fenner, Y. & Gibson, B.K.: 2004, Nature, 303, 59. Lazarian, A., de Gouveia Dal Pino, E.M., Melioli, C. (Eds.): 2015, Lewin, W.H.G., van Paradijs, J., van den Heuvel, E.P.J. (Eds.): 1995, Lin, D.N.C., Papaloizou, J.C.B.: 1996, Lasota, J.-P.: 2016, Isella, A., Carpenter, J.M., Sargent, A. I: 2009, ApJLamzin, 701, S.A., 260-282. Bisnovatyi-Kogan, G.S., Errico, L., Giovannelli, F., Katysheva, N.A., Rossi, C., Larson, R.B.: 2003, Rep. Prog. Phys. 66, 1651-1697. Lasota, J.-P.: 2001, New Astron. Rev. 45, 449. Kurosawa, R., Romanova, M.M.: 2014, in Isella, A.: 2006, Kononov, D.A., Giovannelli, F., Bruni, I., Bisikalo, D.V.: 2012, A&AKotze, 538, E.J., id. Potter, S.B., A94, McBride, 7 V.A.: pp. 2015, A&A 579,Kotze, id. E.J., A77, Potter, 9 S.B., pp. McBride, V.A.: 2016, A&A 595,Kratter, id. K., A47, Lodato, 12 G.: pp. 2016, Annu. Rev. Astron. Astrophys.Kurita 54, S. 271-311. et al. (TSUBAME Team): 2015, arXiv:1503.01975. Kilkenny, D., Reed, M.D., O’Donoghue, D., Kawaler, S.D., Mukadam, A. et al.: 2003, MNRAS, de Jager, O.C., Meintjes, P.J., O’Donoghue, D., Robinson, E.L.:Kardashev, N.S., 1994, Novikov, MNRAS, I.D., 267, Lukash, 577-588. V.N., Pilipenko, S.V., Mikheeva, E.V. et al.: 2014, Media Springer-Verlag Berlin Heidelberg, 627 pp. Systems Hindawi Publ. Co. Adv. in Astron. Vol. 2010, ID 349171, 6 pages. 302, 54-63. (Ed.), Astrophysics and Space Science Library,Springer-Verlag Volume Berlin 440. Heidelberg, ISBN p. 978-3-662-52857-0. 1. Astrophysics Series, Cambridge, MA: Cambridge University0-521-41684-1. Press, pp. xii + 662. ISBN Vittone, A.A.: 1996, A&A 306, 877. University, Italy. 345, 834-846. Physics-Uspekhi Vol. 57, Issue 12, article id. 1199-1228. [135] [136] [137] [132] [133] [134] [130] [131] [128] [129] [125] [126] [127] [123] [124] [118] [119] [120] [121] [122] [116] [117] Accretion Processes in Astrophysics [114] [115] PoS(APCS2016)001 , B. , The , E. Bozzo, P. , MNRAS 279, Franco Giovannelli , D. Lemke, M. Stickel & , Lecture Notes in Physics Protostars and Planets V , Mannings, V., Boss, A.P., Physics at the Magnetospheric Boundary 41 Protostars and Planets IV ISO Surveys of a Dusty Universe , J.F. Alves & M.J. McCaughrean (Eds.), ESO Accretion Disks - New Aspects Magnetic collimation by accretion discs of quasars and stars Astrotomography, Indirect Imaging Methods in Observational Astronomy Nather, R.E., Winget, D.E., Clemens, J.C., Hansen, C.J., Hine,Natta, B.P.: A., 1990, Grinin, ApJ, V., Mannings, 361, V.: 309-317. 2000, in Obara, L., Cwiek, A., Cwiok, M., Majcher, A., Mankiewicz, L., Zarnecki, A.F.: 2014, Rev.Orosz, Mex. J.A., Remillard, R.A., Bailyn, C.D., McClintock, J.E.: 1997, ApJL 478, L83. Mundt, R., Fried, J.W.: 1983, ApJ 274, L83-L86. Nagase, F.: 1989, PASJ 41, no. 1, 1-79. Meyer, M.R., Backman, D.E., Weinberger, A.J., Wyatt, M.C.: 2007, in Meyer-Hofmeister, E., Spruit, H.: 1997, Mullally, F., Coughlin, J.L., Thompson, S.E., Rowe, J., Burke, C. et al.: 2015, ApJS, 217, 31 (16pp). Meyer, M.R., Hillenbrand, L.A., Backman, D., Beckwith, S., Bouwman, J. et al.: 2006, PASP 118, McCaughrean, M.J., O’dell, C.R.: 1996, AJ 111, 1977-1987. de Martino, D., Sala, G., Balman, S., Bernardini,Menou, F., Bianchini, K.: A. 2008, et lecture al.: at 2015, Nordita, arXiv150102767. Stockholm, Sweden,Meyer, November. M.R., Beckwith, S.V.W.: 2000, in Meyer, M.R., Backman, D., Beckwith, S.V.W., Brooke, T.Y., Carpenter, J.M. et al.: 2002, in Marsh, T.R., Horne, K.: 1988, MNRAS 235, 269-286. Lynden-Bell, D., Pringle, J.E.: 1974, MNRAS 168, 603-637. Machida, M.N., Inutsuka, S., Matsumoto, T.: 2010, ApJManara, 724, C.F., 1006-1020. Rosotti, G., Testi, L., Natta, A., Alcalá,Mankiewicz, J.M. L., et Batsch, al.: T., Castro-Tirado, 2016, A., A&A Czyrkowski, 591, H., id. Cwiek, L3, A. 6 et pp. al.: 2014, Rev. Mex. Mantle, V.J., Bath, G.T.: 1983, MNRAS 202, 151. Marsh, T.R.: 2001, in Lynden-Bell, D.: 1996, Lovelace, R.V.E., Romanova, M.M.: 2014, in A&A Conf. Ser., 45, 118-122. K. Wilke (Eds.), Lecture Notes in Physics 548, 341. Origin of Stars and Planets: The VLT View 487, 356 pp. Russell, S.S. (Eds.), (Book - Tucson: University of Arizona Press), p. 559-588. ASTROPHYSICS SYMPOSIA. ISBN 3-540-43541-7. Springer-Verlag, 463-470. 1690-1710. 389-401. H.M.J. Boffin, D. Steeghs & J. Cuypers (Eds.), Lecture Notes in Physics 573, 1-27. Reipurth, D. Jewitt & K. KeilarXiv:astro-ph/0606399. (Eds.), 951 pp., University of Arizona Press, Tucson, p. 573-588. Also A&A Conf. Ser., 45, 7-11. Kretschmar, M. Audard, M. Falanga & C. Ferrigno (Eds.), EPJ Web of Conferences 64, id. 05003. [160] [161] [156] [157] [158] [159] [154] [155] [152] [153] [149] [150] [151] [146] [147] [148] [142] [143] [144] [145] [139] [140] [141] Accretion Processes in Astrophysics [138] PoS(APCS2016)001 , Franco Giovannelli Death of Massive Stars: ˝ UC209, Society for Industrial , Ph.D. Thesis (Scuola Normale Suzaku-MAXI 2014: Expanding the , Cambridge, UK: Cambridge University , ARA&A 19, 137-162. 42 , E. Bozzo, P. Kretschmar, M. Audard, M. Falanga & C. Theory of Accretion Disks I: Angular Momentum Transport , P. Roming, N. Kawai & E. Pian (Eds.), Proc. IAU Symp. No. , M. Ishida, R. Petre & K. Mitsuda (Eds.), Proc. Conf. held 19–22 Adaptive Optics in Astronomy Working on the Fringe: Optical and IR Interferometry from Ground and Space Accretion Discs in Astrophysics The First Black Holes in the Cosmic Dark Ages , ARA&A 33, 505-540. ´ ´ nski, B.: 1965, AcA, 15, 89. nski, B.: 1977, ApJ 216, 822. Sakurai,Y. Inayoshi, K., Haiman, Z.: 2016, MNRAS 461,Salewski, 4496-4504. M., Geiger, B., Heidbrink, W.W., Jacobsen, A.S., S B Korsholm, S.B., et al. (theSargent, ASDEX A.I., Beckwith, S.V.W.: 1987, ApJ 323, 294-305. Saito, Y., Yatsu, Y., Yoshii, T., Usui, R., Kurita, S. et al., 2014, in Roddier, F. (Ed.): 2004, Romanova, M.M., Lovelace, R.V.E., Bachetti, M., Blinova, A.A., Koldoba, A.V. et al.: 2014, in Rucinski, S.M.: 1985, AJ 90, 2321-2330. Saito, Y., Yatsu, Y., Nakajima, H., Kawai, N., Asano, K. et al.: 2012, in Roddier, F.: 1999, in Raguzova, N.V., Lipunov, V.M.: 1999, A&A 349, 505. Reed, M.D., Harms, S.L., Poindexter, S., Zhou, A.-Y., Eggen, J.R. et al.: 2011, MNRAS,Reimer, 412, T.W., Welsh, W.F., Mukai, K., Ringwald, F.A.: 2008, ApJ,Ricker, 678, G.R., 376-384. Winn, J.N., Vanderspek, R., Latham, D.W., Bakos, G.Á et al.: 2015, JournalRix, of H-W., Bovy, J.: 2013, A&A Rev. 21, article id. 61. Pringle, J.E.: 1981, Prusti, T. et al. (Gaia Collaboration): 2016, A&A 595, id.A1, 36 pp. Paczy Papaloizou, J.C.B., Lin, D.N.C.: 1995, Patterson, J.: 1979, ApJ 234, 978-992. Patterson, J.: 1994, PASP, 106, 209-238. Pekurovsky, D.: 2012, Siam J. Sci. Comput. Vol. 34, No. 4, pp. C192 Pacucci, F., Volonteri, M., Ferrara, A.: 2015, MNRAS 452,Paczy Issue 2, 1922-1933. Pacucci, F.: 2016, Frontiers of the X-ray Universe February, 2014 at Ehime University, Japan, p. 210. Upgrade Team): 2015, Plasma Phys. Control. Fusion 57, 014021, 10 pp. S.C. Unwin & R.V. Stachnik (Eds.), ASP Conf. Ser. 194. 318. Ferrigno (Eds.), EPJ Web of Conferences 64, id. 05001. Supernovae and Gamma-Ray Bursts 279, 387-388. Physics at the Magnetospheric Boundary Press, pp. 419. ISBN 0521612144. 371-390. Astronomical Telescopes, Instruments, and Systems, Volume 1, id. 014003. Superiore - Pisa, Italy), 196 pages. Processes and Applied Mathematics. [183] [184] [185] [182] [179] [180] [181] [177] [178] [174] [175] [176] [170] [171] [172] [173] [167] [168] [169] [163] [164] [165] [166] Accretion Processes in Astrophysics [162] PoS(APCS2016)001 ˝ U , , , G. , B. Franco Giovannelli Protostars and Planets V Space Telescopes and Instrumentation The Golden Age of CVs and Related Objects , F. Giovannelli (ed.), SIDEREA, Roma, Italy, p. 3. 43 Structure and Dynamics of the Interstellar Medium Black Holes, White Dwarfs, and Neutron Stars: The Physics of The new cosmos: an introduction to astronomy and astrophysics , Tadayuki Takahashi et al. (eds.), Proc. SPIE, 9144, 25 The Formation and Early Evolution of Stars: From Dust to Stars and Planets Galactic Accreting Sources , John Wiley & Sons, p. 396. . Unsoeld, A., Baschek, B.: 2001, Watson, A.M., Stapelfeldt, K.R., Wood, K., Ménard, F.: 2007, in Wheatley, P.J., Mauche, C.W., Mattei, J.A.: 2003, MNRAS 345, 49. Takahashi, T., den Herder, J.-W.A., Bautz, M.: 2014a, in Takahashi, T. et al. (ASTRO-H Science Working Group): 2014b, arXiv:1412.2351v1 [astro-ph.HE] Smak, J.: 1984b, PASP, 96, 5. Smak, J.: 1985, in Smirnov, A.V., Baryshev, A.M., Pilipenko, S.V., Myshonkova, N.V., Bulanov, V.B. et al.: 2012, SPIE Stockman, H.S.: 1977, ApJL 218, L57-L60. Strom, K.M., Strom, S.E., Edwards, S., Cabrit, S., Skrutskie, M.F.: 1989, AJ 97, 1451-1470. Smak, J.: 1981b, AcA 31, 395. Smak, J.: 1984a, AcA, 34, 161. Shimokawabe, T., Kawai, N., Kotani, T., Yatsu, Y., Ishimura, T.Siudek, et M., al.: Batsch, 2008, T., AIPC, Castro-Tirado, 1000, A.J., 543-546. Czyrkowski, H., Cwiok, M. et al: 2011, Acta Smak, J.: 1962, AcA 12, 28. Smak, J.: 1971, AcA 21, 15. Smak, J.: 1981a, AcA 31, 25. Shakura, N.I., Sunyaev, R.A.: 1973, A&A 24, 337. Shapiro, S.L., Teukolsky, S.A.: 1983, Schulz, N.S.: 2012, Schulze-Makuch, D. & Davies, P.: 2013, JBIS, 66, 11. Shahbaz, T., Bandyopadhyay, R.M., Charles, P.A., Wagner, R.M., Muhli, P., et al.: 1998, MNRAS Shakura, N.I.: 1972, Astron. Zh. 49, 921. Scaringi, S.: 2015, talk at the Palermo Workshop on Sargent, A.I., Beckwith, S.V.W.: 1989, in Reipurth, D. Jewitt & K. Keil (Eds.), 951 pp., University of Arizona Press, Tucson, p. 523-538. III 2014: Ultraviolet to Gamma Ray 7 Dec 2014. 5th ed. Berlin: Springer, xiv, 557 p. Translated by William D. Brewer, ISBN 3540678778. 8442, article id. 84424C, 9 pp. Compact Objects Polytechnica, 51 No. 6, 64-67. Tenorio-Tagle, M. Moles & J. Melnick215-220. (Eds.), IAU Coll. 120, Lecture Notes in Physics, volume 350, Astronomy and Astrophysics Library. ISBN 978-3-642-23925-0. Springer-Verlag Berlin Heidelberg. 300, 1035. [209] [210] [207] [208] [203] [204] [205] [206] [199] [200] [201] [202] [195] [196] [197] [198] [193] [194] [189] [190] [191] [192] [187] [188] Accretion Processes in Astrophysics [186] PoS(APCS2016)001 Protostars Franco Giovannelli Space Telescopes and , Proc. of the SPIE, Vol. 8442, article 44 Numerical Modeling of Space Plasma Flows: 5th international conference of numerical modeling of space , Nikolai V. Pogorelov, Edouard Audit & Gary P. Zank, (Eds.), ASP , Nikolai V. Pogorelov, Edouard Audit, Phillip Colella & Gary P. Zank (Eds.), ASP , V.B. Reipurth, D. Jewitt & K. Keil (Eds.), 951 pp., University of Arizona Press, Tucson, Zhilkin, A.G., Bisikalo, D.V.: 2011, in Zhilkin, A.G., Bisikalo, D.V., Mason, P.A.: 2012, ARep 56, 257-274. Zhilkin, A.G., Bisikalo, D.V.: 2009, in Wynn, G.A., King, A.R., Horne, K.: 1997, MNRAS,Yamada, 286, T., 436-446. Iwata, I., Ando, M. Doi, M., Goto, T. et al.: 2012, in Yonetoku, D., Mihara, T., Sawano, T., Ikeda, H., Harayama, A. et al.: 2014, Proc.Zhang, of E., the Robinson, SPIE, E.L., Vol. Stiening, R.F., Horne, K.: 1995, ApJ, 454, 447-462. Wolf, S., Malbet, F., Alexander, R., Berger, J.-P., Creech-Eakman, M. et al.: 2012, A&ARv 20, id. White, R.J., Greene, T.P., Doppmann, G.W., Covey, K.R., Hillenbrand, L.A.: 2007, in id. 84421A, 12 pp. Conf. Ser. 444, 91-96. Instrumentation 2012: Optical, Infrared, and Millimeter Wave ASTRONUM-2008 Conf. Ser. 406, 118-123. plasma flows (astronum 2010) 9144, id. 91442S. 52, 83 pp. and Planets p. 117-132. Also arXiv:astro-ph/0604081. [219] [217] [218] [215] [216] [212] [213] [214] Accretion Processes in Astrophysics [211]