DOCSLIB.ORG

Gamma-Ray Burst

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Gamma-Ray Burst Gamma-Ray Burst XIANG DanFeng 2017.12.29 Summary • What is a GRB(Gamma-Ray Burst)? • Short and intense pulses of soft gamma rays with non-thermal spectra • The bursts last from a fraction of a second to several hundred seconds. • Narrowly beamed • Long lasting afterglow(in X-ray, optical, radio wavelengths) • The physical pictures • High energy physical processes • Relativistic effects • Synchrotron emission, inverse Compton scattering • Internal and external shocks • Stellar collapse & neutron star merger Observation features of GRB GRB: observation • Spatial distribution • Prompt Emission • Afterglow • Association with supernovae Spatial Distribution • BATSE (Burst and Transient Source Explorer) Isotropic Cosmic origin! For a constant peak luminosity: 푉/푉푚푖푛 = 0.5 But the observed value: 푉/푉푚푖푛 = 0.348 NOT homogeneous! GRB: observation • Spatial distribution: isotropic but not homogeneous, cosmic origin • Prompt Emission • Fast γ-ray emission, together with X-ray flash(XRF) and possible optical and radio emission(very rare) • Afterglow • Association with supernovae Prompt emission Spectrum • Non-thermal spectrum peaks at a few hundred keV, and many events have a long high-energy tail extending up to GeV. • An empirical fit for the spectrum: broken power- law • Peak Energy: • Break Energy: • Paucity of soft or harder events • Intrinsic or observational artifact? –Not clear Prompt emission: spectrum Hardness vs. duration -18 to 14 s • NHE(no high energy) bursts: • no emission above 300keV(very negative β) 14 to 17 s • Fainter than regular ones • Many bursts have NHE pulses along with regular pulses • High energy tail 47 to 80 s • GRB941017(González et al. 2003) • Remains roughly constant 80 to 113 s • The “tail”(10Mev-200MeV) contains more than 50 times energy than the main γ- ray(30keV-2MeV) energy 113 to 211 s • Low Energy tail • Some bursts have steeper low-energy Spectra of GRB 941017 power spectrum(α>1/3) Prompt emission: Temporal structure Prompt emission: Temporal structure • GRB duration: T90(T50) • the time in which 90% (50%) of the counts of the GRB arrive • Hardness: N(100–300 keV) / N(50–100 keV) • Hardness – duration correlation • Long & short • Ultra-long • Variable • Variability time scale(δt) much GRB920627 shorter than the burst duration • ~80% GRBs show variability structures • The rest have rather smooth light curves with a fast-rise exponential decay(FRED) • Variability luminosity correlation Prompt emission: Temporal structure • Pulses • The bursts are composed of series of individual pulses • Light curve of an individual pulse is a FRED with an average rise-to- decay ratio of 1:3 • The low-energy emission is delayed compared to the high-energy emission • The pulses’ low-energy light curves are wider compared to the high- energy light curves(width ~ E-0.4) • Width-symmetry-intensity correlation: High intensity pulses are (statistically) more symmetric (lower decay-to-rise ratio) and with shorter spectral lags • Hardness-intensity correlation: The instantaneous spectral hardness of a pulse is correlated to the instantaneous intensity GRB: observation • Spatial distribution: isotropic but not homogeneous, cosmic origin • Prompt Emission • Fast γ-ray emission, together with X-ray flash(XRF) and possible optical and radio emission(very rare) • Afterglow • slowly fading emission at longer wavelength • Association with supernovae Afterglow • X-ray • Optical and IR • Radio Venn diagram(till 2001) • X-ray −훽 −훼 • 푓휈(푡) ∝ 휈 푡 (α~1.4, β~0.9) • Normal distribution of the flux in 1-10keV, 11h after burst • Constant luminosity • Beam effect • Optical and IR afterglow • Power-law decay (~t-α), or broken power law −α1 • Fν(t)=f*(t / t*) {1−exp[−(t (α1−α2) (α1−α2) GRB 990510 / t*) ](t / t*) }. • Power-law spectrum(~ν-β) • Absorption lines • Providing information of the host galaxy: distance and redshift • Dark GRBs mag Observed • ~50% GRBs do not have optical afterglow • Observational artifact? Days after the burst Absorption, higher z, or intrinsically fainter? • Radio afterglow GRB 970508 • ~50% GRBs have radio afterglow, among which ~80% have optical counterparts Afterglow of short GRB GRB 130603B GRB 050724 GRB: observation • Spatial distribution: isotropic but not homogeneous, cosmic origin • Prompt Emission • Fast γ-ray emission, together with X-ray flash(XRF) and possible optical and radio emission(very rare) • Afterglow • slowly fading emission at longer wavelengths • Only Long bursts • Association with supernovae • Related to stellar death • Association with GRB 090618 supernovae(SNe) • A SN bump in the afterglow • Only the long bursts • The GRB SNe are very different from normal type Ib/c supernovae Physical Processes in GRB Physical Process: Relativistic Motion • For gamma photons to produce e+e- pairs: • We get a optically thick source! • Considering relativistic motion, the source is optically thin! • Relativistic time effect 푅 −푅 푅 −푅 • 훿푡 = 2 1 − 2 1 ≈ (푅 − 푅 )/2푐Γ2 푣 푐 2 1 • 푅 = 2훿푡푐Γ2 Physical Process: Relativistic shocks • Hugoniot shock jump conditions(when the upstream matter is cold): Physical Process: Particle acceleration • How the electrons been accelerated? • diffuse shock acceleration model • The role of magnetic filed • The acceleration resulted in a power law spectrum in form of : 푁 퐸 d퐸 ∝ 퐸−푝d퐸 • With: Physical Process: Synchrotron • Energy source for the prompt emission and afterglow • To study the synchrotron emission, you need to consider the motion of the electron and the source • In observer’s frame: • Power( in local frame): • Cooling time(in observer’s frame): Physical Process: Synchrotron • Synchrotron spectrum(optical thin) 1/3 • Sum of power law: 퐹휈 ∝ 휈 • Peak power at 휈푠푦푛(훾푒): • The overall spectrum: sum of emission of all electrons • Self absorption: 휈푎 • For intermediate frequency: Cooling of electrons • Fast cooling(훾푒,푚푖푛 > 훾푒,푐) • Slow cooling(훾푒,푚푖푛 < 훾푒,푐) Synchrotron spectrum • Slow cooling(훾푒,푚푖푛 < 훾푒,푐) • Fast cooling(훾푒,푚푖푛 > 훾푒,푐) • Jets Considering a spherical shell with constant velocity • Time delay for light from angle θ: 푅(1 − cos 휃)/푐 ≈ 푅휃2/2푐 • Relativistic beaming: 휃~1/Γ • Jet angle: 휃푗~1/Γ −훼 • For an instantaneous flash of power law spectrum 푓휈 ∝ 휈 , the observed flux will decay as power law with 푡−(2−훼) at late times Physical Process: Inverse Compton scattering • The photons earn energy through interaction with electrons • Comptonization parameter 휖푒 • 푌 = 푖푓 푈푒 ≪ 푈퐵 푈퐵 • 푌 = 푈푒/푈퐵 푖푓 푈푒 ≫ 푈퐵 2 • Add ultrahigh energy component to the spectrum(훾푒 ) • Speed up cooling, shorten cooling time tsyn(by a factor of Y) Physical Mechanics and Progenitors Core-Collapse of massive stars • Association with supernovae SN1998bw SN2002dh etc. Core-collapse > central engine > Merger of compact stars : kilonova sGRB prompt emission & afterglow Kilonova Gravitational wave & sGRB GW170817/GRB170817A/AT2017gfo Multi- Messenger Astronomy!! Tidal disruption events GRB 110328A(Swift J2058.4+0516) Unanswered questions • what is the composition of jet/ejecta (baryonic, e± or magnetic outflow)? • how are γ-rays, particularly of energy less than ∼10 MeV, produced? • is a black hole or a rapidly rotating, highly magnetized, neutron star (magnetar) produced in GRBs? • what is the mechanism by which relativistic jets are launched? • what are the properties of long and short duration GRB progenitor stars? References • Kumara, P., Zhang B. The physics of gamma-ray bursts & relativistic jets. PhR, 561, 1-109(2015) • Piran T. The physics of gamma-ray bursts. RvMP, 76, 1143- 1210(2004) Thanks GRB energetics • Isotropic luminosity function(dlnL) • Related to star formation rate • NOT isotropic but beamed 휃2 • 퐸 = 퐸 훾 2 훾,푖푠표 Afterglow Associated with prompt emission • Central engine late central • Shocks engine activities • Jet forward shock External shock Jet break X-ray afterglow.
Load more

Recommended publications
  • Radio Galaxies and Quasars
    Published in "Galactic and Extragalactic Radio Astronomy", 1988, 2nd edition, eds. G.L. Verschuur and K.I. Kellerman. 13. RADIO GALAXIES AND QUASARS Kenneth I. Kellermann and Frazer N. Owen Table of Contents INTRODUCTION Optical Counterparts Radio Source Properties Radio Spectra Energy Considerations LOW-LUMINOSITY SOURCES Spiral, Seyfert, and Irregular Galaxies Elliptical Galaxies COMPACT SOURCES Self-Absorption Inverse Compton Radiation Polarization Structure Variability Source Dynamics and Superluminal Motion Relativistic Beaming EXTENDED SOURCES Jets, Lobes, and Hot Spots Jet Physics SUMMARY REFERENCES 13.1. INTRODUCTION All galaxies and quasars appear to be sources of radio emission at some level. Normal spiral galaxies such as our own galactic system are near the low end of the radio luminosity function and have radio luminosities near 1037 erg s-1. Some Seyfert galaxies, starburst galaxies, and the nuclei of active elliptical galaxies are 100 to 1000 times more luminous. Radio galaxies and some quasars are powerful radio sources at the high end of the luminosity function with luminosities up to 1045 erg s-1. For the more powerful sources, the radio emission often comes from regions well removed from the associated optical object, often hundreds of kiloparsecs or even megaparsecs away. In other cases, however, particularly in active galactic nuclei (AGN) or quasars, much of the radio emission comes from an extremely small region with measured dimensions of only a few parsecs. The form of the radio- frequency spectra implies that the radio emission is nonthermal in origin; it is presumed to be synchrotron radiation from ultra-relativistic electrons with energies of typically about 1 GeV moving in weak magnetic fields of about 10-4 gauss (see Section 1.1).
    [Show full text]
  • Relativistic Effects
    Relativistic Effects 1 Introduction The radio-emitting plasma in AGN contains electrons with relativistic energies. The Lorentz factors of the emitting elec- trons are of order 1026– . We now know that the bulk motion of the plasma is also moving relativistically – at least in some regions although probably “only” with Lorentz factors about 10 or so. However, this has an important effect on the prop- erties of the emitted radiation – principally through the ef- fects of relativistic beaming and doppler shifts in frequency. This in turn affects the inferred parameters of the plasma. Relativistic Effects ©Geoffrey V. Bicknell 2 Summary of special relativity For a more complete summary of 4-vectors and Special Rel- ativity, see Rybicki and Lightman, Radiative Processes in As- trophysics, or Rindler, Special Relativity High Energy Astrophysics: Relativistic Effects 2/93 2.1 The Lorentz transformation y S y S V x x The primed frame is moving wrt to the unprimed frame with a velocity v in the x–direction. The coordinates in the primed frame are related to those in the unprimed frame by: High Energy Astrophysics: Relativistic Effects 3/93 Vx x= xvt– t= t – ------ c2 y = y z = z (1) v 1 = -- = ------------------- c 1 – 2 We put the space-time coordinates on an equal footing by putting x0 = ct. The the xt– part of the Lorentz transforma- tion can be written: x= x – x0 x0= x0 – x (2) The reverse transformation is: High Energy Astrophysics: Relativistic Effects 4/93 x = x + Vt yy= zz= Vx (3) t = t + -------- c2 i.e., x = x+ x0 x0 = x0+ x (4) High Energy Astrophysics: Relativistic Effects 5/93 2.2 Lorentz–Fitzgerald contraction 2.3 Time dilation y y V S S x x High Energy Astrophysics: Relativistic Effects 6/93 y y S S V L0 x x 2 1 x – x = L0 2 1 x – x = x2 – x1 – Vt2 – t1 –1 L0 = L L = L0 High Energy Astrophysics: Relativistic Effects 7/93 Consider a clock at a stationary position in the moving frame which registers a time interval T0.
    [Show full text]
  • Analysis of Kepler Active Galactic Nuclei Using a Revised Kirk, Rieger, Mastichiadis (1998) Model Sarah M
    Florida International University FIU Digital Commons FIU Electronic Theses and Dissertations University Graduate School 6-12-2014 Analysis of Kepler Active Galactic Nuclei Using A Revised Kirk, Rieger, Mastichiadis (1998) Model Sarah M. Dhalla Florida International University, [email protected] DOI: 10.25148/etd.FI14071133 Follow this and additional works at: https://digitalcommons.fiu.edu/etd Recommended Citation Dhalla, Sarah M., "Analysis of Kepler Active Galactic Nuclei Using A Revised Kirk, Rieger, Mastichiadis (1998) Model" (2014). FIU Electronic Theses and Dissertations. 1521. https://digitalcommons.fiu.edu/etd/1521 This work is brought to you for free and open access by the University Graduate School at FIU Digital Commons. It has been accepted for inclusion in FIU Electronic Theses and Dissertations by an authorized administrator of FIU Digital Commons. For more information, please contact [email protected]. FLORIDA INTERNATIONAL UNIVERSITY Miami, Florida ANALYSIS OF KEPLER ACTIVE GALACTIC NUCLEI USING A REVISED KIRK, RIEGER, MASTICHIADIS (1998) JET MODEL A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in PHYSICS by Sarah Mohammed Dhalla 2014 To: Interim Dean Michael R. Heithaus College of Arts and Sciences This thesis, written by Sarah Mohammed Dhalla, and entitled Analysis of Kepler Active Galactic Nuclei Using a Revised Kirk, Rieger, & Mastichiadis (1998) Jet Model, having been approved in respect to style and intellectual content, is referred to you for judgment. We have read this thesis and recommend that it be approved. Caroline Simpson Walter Van Hamme James R. Webb, Major Professor Date of Defense: June 12, 2014 The thesis of Sarah Mohammed Dhalla is approved.
    [Show full text]
  • 11 Jets and Gamma-Ray Burst Unification Schemes
    11 Jets and Gamma-Ray Burst Unification Schemes Jonathan Granot1 and Enrico Ramirez-Ruiz2 (1) Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield, Herts, AL10 9AB, UK (2) Astronomy and Astrophysics Department, University of California, Santa Cruz, CA 95064, USA 11.1 Evidence for bulk relativistic motion in gamma-ray bursts The first line of evidence for ultra-relativistic bulk motion of the outflows that produce GRBs arises from the compactness argument. It relies on the observed short and intense pulses of gamma rays and their non-thermal en- ergy spectrum that often extends up to high photon energies. Together, these facts imply that the emitting region must be moving relativistically. In order to understand this better, let us first consider a source that is either at rest or moves at a Newtonian velocity, β v/c 1, corresponding to a ≡ ≪ bulk Lorentz factor Γ (1 β2)−1/2 1. For such a source the observed ≡ − ≈ variability timescale (e.g., the width of the observed pulses) ∆t, implies a typical source size or radius R < c∆t, due to light time travel effects (for sim- plicity we ignore here cosmological effects, such as redshift or time dilation). GRBs often show significant variability down to millisecond timescales, im- plying R< 3 107(∆t/ 1 ms) cm. At cosmological distances their isotropic × equivalent luminosity, L, is typically in the range of 1050 1053 ergs−1. − In addition, the (observed part of the) εFε GRB spectrum typically peaks around a dimensionless photon energy of ε E /m c2 1, so that (for ≡ ph e ∼ a Newtonian source) a good fraction of the total radiated energy is carried by photons that can pair produce with other photons of similar energy.
    [Show full text]
  • Relativistic Boost As the Cause of Periodicity in a Massive Black-Hole Binary Candidate
    Relativistic boost as the cause of periodicity in a massive black-hole binary candidate Daniel J. D’Orazio1, Zoltan´ Haiman1 & David Schiminovich1 To appear as a Letter in the September 17, 2015 isse of Nature 1Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 Because most large galaxies contain a central black hole, and galaxies often merge1, black- hole binaries are expected to be common in galactic nuclei2. Although they cannot be imaged, periodicities in the light curves of quasars have been interpreted as evidence for binaries3–5, most recently in PG 1302-102, with a short rest-frame optical period of 4 yr6. If the orbital period matches this value, then for the range of estimated black hole masses the components would be separated by 0.007-0.017 pc, implying relativistic orbital speeds. There has been much debate over whether black hole orbits could be smaller than 1 pc7. Here we show that the amplitude and the sinusoid-like shape of the variability of PG 1302-102 can be fit by relativistic Doppler boosting of emission from a compact, steadily accreting, unequal-mass binary. We predict that brightness variations in the ultraviolet light curve track those in the optical, but with a 2-3 times larger amplitude. This prediction is relatively insensitive to the details of the emission process, and is consistent with archival UV data. Follow-up UV and optical observations in the next few years can test this prediction and confirm the existence of a binary black hole in the relativistic regime.
    [Show full text]
  • Relativistic Beaming and Gamma-Ray Brightness of Blazars
    A&A 512, A24 (2010) Astronomy DOI: 10.1051/0004-6361/200913740 & c ESO 2010 Astrophysics Relativistic beaming and gamma-ray brightness of blazars T. Savolainen1,D.C.Homan2,T.Hovatta3,4,M.Kadler5,6,7,Y.Y.Kovalev8,1,M.L.Lister3,E.Ros1,9, and J. A. Zensus1 1 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany e-mail: [email protected] 2 Department of Physics and Astronomy, Denison University, Granville, OH 43023, USA 3 Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907, USA 4 Metsähovi Radio Observatory, Helsinki University of Technology TKK, Metsähovintie 114, 02540 Kylmälä, Finland 5 Dr. Karl Remeis-Observatory & ECAP, Friedrich-Alexander University Erlangen-Nuremberg, Sternwartstr. 7, 96049 Bamberg, Germany 6 CRESST/NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA 7 Universities Space Research Association, 10211 Wincopin Circle, Suite 500 Columbia, MD 21044, USA 8 Astro Space Center of Lebedev Physical Institute, Profsoyuznaya 84/32, 117997 Moscow, Russia 9 Departament d’Astronomia i Astrofísica, Universitat de València, 46100 Burjassot, Valencia, Spain Received 25 November 2009 / Accepted 12 January 2010 ABSTRACT Aims. We investigate the dependence of γ-ray brightness of blazars on intrinsic properties of their parsec-scale radio jets and the implication for relativistic beaming. Methods. By combining apparent jet speeds derived from high-resolution VLBA images from the MOJAVE program with millimetre- wavelength flux density monitoring data from Metsähovi Radio Observatory, we estimate the jet Doppler factors, Lorentz factors, and viewing angles for a sample of 62 blazars. We study the trends in these quantities between the sources which were detected in γ-rays by the Fermi Large Area Telescope (LAT) during its first three months of science operations and those which were not detected.
    [Show full text]
  • Relativistic Beaming and Orientation Effects in Core-Dominated Quasars
    the educational, scientificab u sa am111IlllI! 111111I and cutural internationalXA237 (A) centre ney agnc for theoretical physicsI RELATIVISTIC BEAMING AND ORIENTATION EFFECTS IN CORE-DOMINATED QUASARS A.A. U~bachukwuS and4 A.E. Chukwude Available at: http://wvw. ictp. trieste. it/pub- of f IC/2002/94 United Nations Educational Scientific and Cultural Organization and International Atomic Energy Agency THE ABDUS SALAM INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS RELATIVISTIC BEAMING AND ORIENTATION EFFECTS IN CORE-DOMINATED QUASARS A.A. Ubachukwu' Department of Physics and Astronomy, University of Nigeria, Nsukka, Nigeria and The Abdus Salam International Centre for Theoretical Physics, Trieste, Italy and A.E. Chukwude Department of Physics and Astronomy, University of Nigeria, Nsukka, Nigeria. Abstract In this paper, we investigate the relativistic beaming effects in a well-defined sample of core- dominated quasars using the correlation between the relative prominence of the core with respect to the extended emission (defined as the ratio of the core- to the lobe- flux density measured in the rest frame of the source) and the projected linear size as an indicator of relativistic beaming and source orientation. Based on the orientation-dependent relativistic beaming and unification paradigm for high luminosity sources in which the Fanaroff-Riley class-1l radio galaxies form the unbeamed parent population of both the lobe- and core-dominated quasars which are expected to lie at successively smaller angles to the line of sight, we find that the flows in the cores of these core-dominated quasars are highly relativistic, with optimum bulk Lorentz factor, -yp 6 - 16, and also highly anisotropic, with an average viewing angle, - 90 - 160.
    [Show full text]
  • Unified Schemes for Radio-Loud Active Galactic Nuclei
    Invited Review Paper for PASP Unified Schemes for Radio-Loud Active Galactic Nuclei C. Megan Urry Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD, 21218 Electronic mail: [email protected] and Paolo Padovani Dipartimento di Fisica, II Universit`adi Roma “Tor Vergata” Via della Ricerca Scientifica 1, I-00133 Roma, Italy Electronic mail: [email protected] ABSTRACT The appearance of active galactic nuclei (AGN) depends so strongly on orientation that our current classification schemes are dominated by random pointing directions instead of more interesting physical properties. Light from the centers of many AGN is obscured by optically thick circumnuclear matter, particularly at optical and ultraviolet wavelengths. In radio-loud AGN, bipolar jets emanating from the nucleus emit radio through gamma-ray light that is relativistically beamed along the jet axes. Understanding the origin and magnitude of radiation anisotropies in AGN allows us to unify different classes of AGN; that is, to identify each single, underlying AGN type arXiv:astro-ph/9506063v2 9 Jun 1995 that gives rise to different classes through different orientations. This review describes the unification of radio-loud AGN, which include radio galaxies, quasars, and blazars. We describe the classification and general properties of AGN. We summarize the evidence for anisotropic emission caused by circumnuclear obscuration and relativistic beaming. We outline the two most plausible unified schemes for radio-loud AGN, one linking the high-luminosity sources (quasars and luminous radio galaxies) and one the low-luminosity sources (BL Lac objects and less luminous radio galaxies). Using the formalism appropriate to samples biased by relativistic beaming, we show the population statistics for two schemes are in accordance with available data.
    [Show full text]
  • On the Relativistic Beaming and Orientation Effects in Core-Dominated Quasars
    J. Astrophys. Astr. (2002) 23, 235–242 On the Relativistic Beaming and Orientation Effects in Core-Dominated Quasars ∗ A. A. Ubachukwu & A. E. Chukwude Department of Physics and Astronomy, University of Nigeria Nsukka, Nigeria ∗Regular Associate of the Abdus Salam ICTP, Trieste Italy Received 2002 July 31; accepted 2002 December 11 Abstract. In this paper, we investigate the relativistic beaming effects in a well-defined sample of core-dominated quasars using the correlation between the relative prominence of the core with respect to the extended emission (defined as the ratio of core- to lobe- flux density measured in the rest frame of the source) and the projected linear size as an indicator of rela- tivistic beaming and source orientation. Based on the orientation-dependent relativistic beaming and unification paradigm for high luminosity sources in which the Fanaroff-Riley class-II radio galaxies form the unbeamed par- ent population of both the lobe- and core-dominated quasars which are expected to lie at successively smaller angles to the line of sight, we find that the flows in the cores of these core-dominated quasars are highly rel- ativistic, with optimum bulk Lorentz factor, γopt ∼ 6–16, and also highly anisotropic, with an average viewing angle, ∼ 9◦–16◦. Furthermore, the largest boosting occurs within a critical cone angle of ≈ 4◦–10◦. Key words. Galaxies: active, jets, quasars: general. 1. Introduction The phenomenology of active galactic nuclei (AGNs) involves a supermassive black hole which releases relativistic outflows of energetic particles by accretion of mat- ter through an accretion disk surrounded by an optically thick torus.
    [Show full text]
  • General Relativistic Radiative Transfer: Applications to Black-Hole Systems
    Chin. J. Astron. Astrophys. Vol. 0, TO. 0, (200x) 000-00o Chinese Journal of (http1www.chjaa.ory) Astronomy and Astrophysics .' General Relativistic Radiative Transfer: Applications to Black-Hole Systems Kinwah WUI *, Steven V. FUerst2, Yosuke Mizuno3, Ken-Ichi Nishikawa3 , Graziella Branduardi-Raymont1 and Khee-Gan Lee',· 1 Mullard Space Science Laboratory, University College London, Holmbury St Mary, Surrey 1U15 6NT, United Kingdom 2 Kavli lllstitute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94304, USA 3 ASA-MSFC/ SSTC, 320 Sparkman Drive, Rnntsville, AL 35805, USA 4 Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA Received 2007 month day; accepted 2007 month day Abstract We present general relativistic radiation transfer formulations which include opacity effects due to absorption, emission and scattering explicitly. We consider a moment expansions for the transfer in the presence of scattering. The formulation is applied to calculation emissions from accretion and outflows in black-hole systems. Cases with thin accretion disks and accretion tori are consid­ ered. Effects, such as emission anisotropy, non-stationary flows and geometrical self-occultation are investigated. Polarisation transfer in curved space-time is dis­ cussed qualitatively. Key words: accretion, accretion disks - black hole physics - galaxies:active ­ radiative transfer - relativity 1 INTRODUCTION Observations of the ACN MCC-6-3Q-15 hy ASCA showed Fe Ko emissinn line with a very broad asymmetric profile (Tanaka et al. 1995). The presence of the line was confirmed hy later observations using e.g. Chandra and XMM-Newton. The broad asymmetric Fe Ko lines have also been seen in the spectra of several other ACN (e.g.
    [Show full text]
  • Lorentz Factor Distribution of Blazars from the Optical Fundamental Plane of Black Hole Activity
    Mon. Not. R. Astron. Soc. 000, 1{8 (2016) Printed 6 January 2018 (MN LATEX style file v2.2) Lorentz factor distribution of blazars from the optical Fundamental plane of black hole activity Payaswini Saikia1∗, Elmar K¨ording1 and Heino Falcke1;2 1Department of Astrophysics/IMAPP, Radboud University, Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands 2ASTRON, Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, The Netherlands 6 January 2018 ABSTRACT Blazar radiation is dominated by a relativistic jet which can be modeled at first ap- proximation using just two intrinsic parameters - the Lorentz factor Γ and the viewing angle θ. Blazar jet observations are often beamed due to relativistic effects, complicat- ing the understanding of these intrinsic properties. The most common way to estimate blazar Lorentz factors needs the estimation of apparent jet speeds and Doppler beam- ing factors. We present a new and independent method of constructing the blazar Lorentz factor distribution, using the optical fundamental plane of black hole activ- ity. The optical fundamental plane is a plane stretched out by both the supermassive black holes and the X-ray binaries, in the 3D space provided by their [OIII] line lu- minosity, radio luminosity and black hole mass. We use the intrinsic radio luminosity obtained from the optical fundamental plane to constrain the boosting parameters of the VLBA Imaging and Polarimetry Survey (VIPS) blazar sample. We find a blazar bulk Lorentz factor distribution in the form of a power law as N(Γ) / Γ−2:1±0:4 for the Γ range of 1 to 40. We also discuss the viewing angle distribution of the blazars and the dependence of our results on the input parameters.
    [Show full text]
  • Superluminal Motion and Relativistic Beaming in Blazar Jets
    High Energy Blazar Astronomy ASP Conference Series, Vol. 299, 2003 L.O. Takalo and E. Valtaoja Superluminal Motion and Relativistic Beaming in Blazar Jets K. I. Kellermann, M. L. Lister, and D. C. Homan NRAO, 520 Edgemont Rd., Charlottesville, VA, 22903, U.S.A. E. Ros and J. A. Zensus MPIfR, Auf dem Hugel 69, Bonn, D-53121, Germany M. H. Cohen and M. Russo Astronomy 105-24, Caltech, Pasadena, CA 91125, U.S.A. R. C. Vermeulen ASTRON, P.O. Box 2, NL-7990 AA Dwingeloo, The Netherlands Abstract. High resolution radio observations remain the most direct way to study the formation and evolution of radio jets associated with the accretion onto massive black holes. We report preliminary results of our seven year VLBA observational program to understand the nature of relativistic beaming in blazars and the surrounding environment of massive black holes. Most blazars show an apparent outward flow away from an active core. However, in a few sources the motion appears inward, most likely the result of projection of a curved trajectory which bends back toward along the line of sight. The apparent motion of jet features is not always oriented along the direction separating the feature from the core, and in a few cases we have observed a clear change in the direction and velocity of a feature as it flows along the jet. In other sources, the motion appears to follow a simple ballistic trajectory. We ¯nd no simple relation between the time scales of flux density changes and apparent component velocities. 1. Background It is generally accepted that the blazar phenomenon is due to the anisotropic boosting of the radiation along the direction of motion which gives rise to an apparent enhanced luminosity at all wavelengths if the observer is located close to the direction of motion.
    [Show full text]