PoS(SUPERNOVA)025 http://pos.sissa.it/ ce. al waves for these ground and space ational wave facilities, plans for future tional wave detectors like LISA. It also ques de la Mediterrània) a. Valldemossa Km. 7.5, E-07122 tein Institut, Am Mühlenberg 1, D-14476 ive Commons Attribution-NonCommercial-ShareAlike Licen ∗ [email protected] detector upgrades and the status of the space-based gravita based detectors. This paper briefly summarizes the status of operating gravit describes some of the most promising sources of gravitation Speaker. ∗ Copyright owned by the author(s) under the terms of the Creat c October 3-5 2007 Maó, Menorca, Spain Supernovae: lights in the darkness (XXIII Trobades Científi Alicia M. Sintes Gravitational wave astronomy: now and future Departament de Física, Universitat de les Illes Balears, Cr Palma de Mallorca, Spain. Max-Planck-Institut für Gravitationsphysik, Albert Eins Golm, Germany. E-mail:

PoS(SUPERNOVA)025 Alicia M. Sintes ound differences between Ein- t been successful yet. However, tem consists of two neutron stars reover gravitational waves would e. According to Einstein’s theory e amount of emitted gravitational acting space-time. Like its electro- imation. avity is very weak, compared with ical-horizontal, like an addition symbol o information about the astrophysics n be observed as a radio pulsar from rved inspiral rates agree within exper- ystem behaves according to Einstein’s ron star system PSR 1913+16, discov- sted domain of strongly curved space- y the orbital velocity, the orbital period t to observe must be emitted by massive ime curvature [1, 2]. One of the theory tional waves. As a consequence the two round each other at a higher frequency. ry of gravity that it replaced. The confir- me are called gravitational waves. ripples in space-time that propagate away xis and squeezed along the perpendicular axis, on is transverse to the direction of propaga- t was squeezing now stretches while the stretching ". A small mass placed at various points along the 2 × Gravitational waves have two polarizations. These are vert Gravitational waves have the effect of stretching and contr The prediction of gravitational waves is one of the most prof Any attempts to directly detect gravitational waves have no Gravitation governs the large scale behavior of the Univers " and at 45 degrees to these directions, like an " + Figure 1: Gravitational wave astronomy: now and future " their indirect influence has been measuredered in in the binary 1974 neut by Russellorbiting Hulse each and other. Joe Taylor One [3, ofearth. 4, the Since 5]. neutron the stars This observed radio is sys pulses activeand are and its Doppler change ca shifted over b time can betheory, determined it precisely. will If loose the energy s through the emission of gravita From the observed orbital parameterswaves and one then can the inspiral first rate. compute The th calculated and the obse predictions is that a changing mass distributionfrom can create the source at the speed of light, carrying energy and als neutron stars will decrease their separation and orbiting a of general relativity, gravity can be expressed as a space-t of the source. These freely propagating ripples in space-ti magnetic counterpart, the effect of gravitationaltion radiati and also has twoother polarizations fundamental forces, (see the figure gravitational waves 1). weobjects expec undergoing Because large gr accelerations. stein’s theory of general relativity andmation the Newtonian of theo this conjecture wouldprovide be us fundamental with on information its on own. strongtime, field Mo where gravity, Newtonian the gravity unte is no longer even a poor approx axis squeezes. 1. Introduction gravitational wave shown above will bethen stretched one-halfcycle along one later a the reverse occurs and the axis tha PoS(SUPERNOVA)025 ∼ Alicia M. Sintes Hz from the cos- ough signals in the 10 we are heading into an era ong process, dating to the work t unlike electromagnetic waves, t of some controversy ever since er there are many sources of much object and the observer, whereas e resonant mode of oscillation ( at a level where detectors of very tic waves. Electromagnetic waves f up to several km and operate in a xplosions, to 10 ns of the possibility of earth-incident idea was to use an aluminum bar of the order of the source sizes. These omena, from our own Galaxy up to s, detection methods and sources see nd different view of the universe. In ng, operation and potential upgrading tors may be on ground or in space. hat determine the wavelength, but the ed. This gives rise to the expectation nclude: cryogenic resonant bar detec- erferometer detectors incorporate high ity by observing black hole signatures, llar collapses to neutron stars and black n stars such as pulsars, and the physics urations, suspended optical components y of gravitational waves, in the different Doppler tracking of spacecraft, timing of s in supernova explosions, and, of course, interactions and coalescences, neutron stars over relevant timescales – will be eventually at frequencies near 1 kHz, Weber set out to 23 − 17 − 3 to 10 22 − Hz in the case of ripples in the cosmological background, thr 17 − Gravitational waves come in many different frequencies. Bu Gravitational waves are quite different from electromagne The direct detection of gravitational waves has been subjec The development of gravitational wave detectors has been a l The most predictable sources are binary star systems. Howev it is not the microscopicglobal processes properties deep inside of the the sourcesrange sources, t from leading 10 to wavelengths of cosmological distances. the possibility to discover new kinds of astrophysical phen are easily scattered andgravitational absorbed waves by will dust pass through cloudsthat them between the almost the detection unaffect of gravitationalparticular, waves it will might reveal lead a to newlarge new scale insights a nuclear in matter strong in field neutron grav stars, inner processe Gravitational wave astronomy: now and future imental errors, to within about 0.2% [6]. audio band from the formation of neutron stars in supernova e required to allow a full range of observations and such detec their prediction by Einstein. Howeverof with the the commissioni long baseline detectorswhere this LIGO, controversy GEO600, will VIRGO bepower resolved and stabilized [8]. TAMA, laser These sources, laser complicated int and optical high config performance seismic filters.ultra They high have vacuum arm environment. lengths o 2. The search for gravitational waves 2.1 Resonant mass detectors of Joseph Weber in the 1960sgravitational [9, 10]. waves Stimulated with by amplitude predictio of order 10 build a detector sufficiently sensitive to observe them. His dimension two meter long, and one-half meter diameter, whos mological background itself. The studyfrequency of the bands, full requires diversit complementary approachestors, that laser i interferometer detectors on earth and in space, [7], and references therein. millisecond pulsars, etc. For an overview of frequency band greater astrophysical interest associated with black hole coalescences, low-mass X-ray binaries, such as Sco-X1,holes ste (supernova explosions), rotating asymmetric neutro high strain sensitivity – of the order of 10 of the early universe. The signals from all these sources are PoS(SUPERNOVA)025 rimentalists Alicia M. Sintes [13]. nant gravitational wave detector. R at CERN [12]. The Louisiana everal orders of magnitude. Cryo- over millisecond time scales. The bar, built at the University of also allowed the use of ultra-quiet nal wave strains were likely to be ances of the bar-transducer system. 15 ave also played an important role in Hz, in bands measuring tens of Hertz ucers to convert the bar motion to an − ted in a band around the bar’s resonant √ / d in Legnaro. The Rome group operates . The AURIGA detector [11] is one of this 21 er 10 19 − − 4 or less and could encompass a wide range of frequencies, expe 21 − Joseph Weber at the University of Maryland with the first reso Resonant-mass detectors have their sensitivity concentra Over the ensuing decades, sensitivity has been improved by s With the increasing theoretical confidence that gravitatio Figure 2: latest generation of resonant-mass detectors.two comparable It detectors, is NAUTILUS in locate Frascati and EXPLORE State group operates ALLEGRO on the LSU campus in Baton Rouge frequency, or in a pair ofThe such current bands generation around exhibits sensitivity the of coupled about reson 10 genic technology has reducedSQUID mechanical amplifiers. thermal noise, New vibration and isolatorsthe and achievement of transducers rms h strain sensitivities of about 10 1.6 kHz) would overlap in frequencyMaryland with (see the figure incoming 2), waves. waselectrical fitted signal, with and provided piezoelectric a transd strain sensitivity of ord Gravitational wave astronomy: now and future wide. 2.2 Ground based interferometers of the order of 10 PoS(SUPERNOVA)025 , 20 − er in Liv- Alicia M. Sintes vanced versions, f high strain sensitivities, lson interferometer to achieve ], was 2 m in arm length and cessed in an interferometer), as construction of large scale laser ional wave detectors: a Michelson , allowed for the implementation sioning, a network of gravitational tial sources. . They were 40, 10 and 30 m in uch a means became possible with ity exceeding that of resonant bars, f a gravitational wave, which offered -off at several tens of Hz up to several by Forward [14], and independently, pendulum; this allows free motion when a ges caused by an incident gravitational background seismic noise, were built at sing gravity wave will stretch one arm and d Hz in a 1 Hz bandwidth of about 10 c noise. 5 observatories [20] consist of a 4 km arm length interferomet 1 strain sensitivity in a 1 Hz bandwidth at 1 kHz. Subsequent ad , respectively. After the above prototype demonstrations o 19 16 − − Optical topology used by the laser interferometer gravitat and 10 The first working laser interferometer, built by Forward [16 http://www.ligo.caltech.edu/ The American LIGO There are currently in operation, or in final stages of commis 19 1 − using improved laser stability, optics, and isolation from length and achieved strain sensitivities at several hundre Caltech [17], University of Glasgow [18], and Garching [19] achieved 10 contract the other. Thegravity mirrors wave passes are and suspended also provides by isolation wires from like seismi a sought a more sensitive and wider-band means of detection. S interferometer with Fabry-Perot cavities in the arms. A pas the development of the laserby interferometer, Weiss first [15]. proposed differential This sensitivity device to used the thewave instrument configuration (see arm figure of length 3). the chan compared The Miche to key the idea much was slower thatof speed a the of greatly speed sound increased (accessed of measurement in light pathlengthcorrespondingly a (ac over greater bar) a strain cycle sensitivity. o Figure 3: Gravitational wave astronomy: now and future 10 funding agencies in the US,interferometers. Europe and Japan committed to the wave detectors. These detectorshaving a operate larger now bandwidth (reaching with from a akHz) low sensitiv and frequency cut extending the search to a much broader range of poten PoS(SUPERNOVA)025 2 Alicia M. Sintes system had one complete e analyzed for a variety of d orthogonal beam tubes. opped several times to allow yo Astronomical Observatory. om January 2006 and VIRGO 003, Oct 31 2003 and Feb 22 re in the same vacuum system. tanding with operation at instru- of the LIGO detectors started on nd S4, and happened for 17, 61, ngton, and a 2 km interferometer hose of VIRGO and LIGO in their the LIGO Scientific Collaboration pleting commissioning and the 300 vel technologies is expected to reach ional waves from a range of sources: tochastic background of gravitational GO detectors, three have involved the rs and being this the longest stretch of ll of 2005 (see figure 5). The 3 km long 6 Aerial view of LIGO Hanford site, showing vertex building an http://www.ligo.org/ During the commissioning phase, work in the detectors was st Figure 4: 2 Gravitational wave astronomy: now and future ingston, Louisiana, a 4also km at Hanford. interferometer in The 2Construction Hanford, km of Washi and LIGO 4 began in kmmental 1996 interferometers design and at sensitivity progress having Hanford been has a achieved beenFrench/Italian since outs the VIRGO fa detector [21] nearm Pisa long is Japanese close TAMA to 300The com German/British detector detector, [22] GEO600 [23], is through operating usea of at sensitivity no at the frequencies Tok aboveinitial a operation. few hundred Hz close to t for data taking. These70, "Science and Runs" were 30 called days2005, S1, respectively, also S2, starting respectively. S3 in All a these AugGEO runs 23 detector have 2002, involved and the Feb two LI gravitational 14 had wave 2 the signals by TAMA a involvement. group of Their researches data known wer as and new upper limits have beencoalescing set compact on the binaries, strength pulsars, ofwaves gravitat burst [24, sources 25, and 26, a 27,4th s 28, 29, Nov 30, 2005 31, with 32].from GEO The May having fifth 2007. joined science for This run year data run of ended taking triple on periods coincidence 1st fr data October from 2007 all when three the of LIGO its detecto PoS(SUPERNOVA)025 2007). Alicia M. Sintes ilar upgrade to VIRGO, 002) to S5 (2007) in units of pected to commence early in lving mechanical losses in coat- ted to commence in 2010, with o the LIGO and VIRGO detectors etector teams opens the possibility nd has plans for a future full-scale y in the kHz frequency region and sive optics are likely to be adopted, [34, 35], in Japan. In Australia, the t interferometric detectors is needed ary systems have improved the statis- . Thus plans for an upgraded LIGO, detectors and a European design study at a sensitivity level where a detection e by the LIGO system by a significant n. Thus research groups in the field are next few years [33]. However detection is no way guaranteed, and improvement light to bypass the standard quantum limit tem by 2014. f frequency. (Right) GEO sensitivity in com- 7 , Proposal to the European Commission, Framework Program 7 ( (Left) LIGO instrumental sensitivity for science runs S1 (2 . 3 Einstein gravitational wave Telescope During the next few years following intermediate upgrades t On approximately the same timescale we can expect to see a sim To go beyond this point, however, a number of challenges invo Close coordination and collaboration between the various d 3 Figure 5: Gravitational wave astronomy: now and future http://www.ego-gw.it/ILIAS-GW/FP7-DS/fp7-DS.htm we can expect to see searchescould for be gravitational made. wave signals Recent discoveries oftics additional for compact bin the expected ratefactor, giving of some binary possibility coalescences of detectabl a first detection over the parison to the LIGO detectors during S5. data taking to date at initial design sensitivity. at the current level of sensitivity of the initial detectors already looking towards the next generation of ground based gravitational-wave strain per square root Hz as a function o of the order of ato factor of reach 10 sensitivity to levels 15 whereAdvanced in many LIGO, sensitivity signals of are the are already curren expected wellfull formed. installation and The initial operation upgrade of is the expec upgraded sys the rebuilding of GEOthe as building a of detector a aiming long-baselineACIGA at underground consortium high detector, operates LCGT sensitivit an 80interferometer. m interferometric testbed a ings, thermal loading effects, and the usewill of non-classical have to be met.using Cryogenic materials of test high mirrors thermal and conductivity non-transmis such as silico for such a system funded2008 under the EC Framework 7 program is ex PoS(SUPERNOVA)025 6 10 × Alicia M. Sintes ee (BEPAC) has recom- hase locked, and each spacecraft eded by the Joint Dark Energy int ESA/NASA mission in 2018 ssential for achieving a low false e been signed or are in the process istant binaries; and probably other [36] is a planned space mission to ic plane 1 AU from the Sun and 20 s of gravitational waves. LISA will 4 eters. LISA is designed to measure ve black holes merging in galaxies at ree-floating proof masses forming the twork is a common goal of all projects s, from about 0.1 to 100 millihertz, a ct objects; known binary compact stars oming years. It also enables an efficient ig Bang. ateral triangle with a base length of 5 constellation triangle rotates once per year. 8 Orbit of LISA constellation. On each spacecraft lasers are p Recently the NASA Beyond Einstein Program Advisory Committ The LISA (Laser Interferometer Space Antenna) Project http://lisa.jpl.nasa.gov 4 km. The center ofdegrees the behind triangle the formation Earth. will Each beend spacecraft in will points contain the of two eclipt f threegravitational separate radiation but over not a independent broadband interferom band where at the low Universe frequencie isdetect richly signals populated from in a strong wideall source range distances; of massive black different holes sources: consuming smaller massi and compa stellar remnants; members of knownsources, populations possibly including of relics more of d the extremely early B mended that LISA beMission the (JDEM) Flagship and mission thus LISA of isand the expected to to program, be be producing prec launched data as for a up jo to ten years. Figure 6: Gravitational wave astronomy: now and future transmits and receives light from each of its neighbors. The of continuous observation of gravitational waves overnetwork the data c analysis. Aalarm rate worldwide and network locating signal of sources inand detectors the is is sky. ensured A e by global mutual ne Memorandaof of being Understanding signed. that hav 2.3 LISA: A space-based optical interferometer deploy three satellites in solar orbit forming a large equil PoS(SUPERNOVA)025 . 24 − 10 ∼ Alicia M. Sintes on of 0.01 – 10 Hz. Its pri- vitational waves for ground- by massive astrophysical ob- ased detector LISA. Typical exam- g of intermediate mass black holes act binaries. BBO will also extend ological time-scales and dynamical und super-massive black holes with nd in [7]. Here we only give a brief es from the era of the big bang, at a of the visible Universe would allow rs of massive black holes residing in gy, including kW power level stabi- at 0.1 Hz is planned to be ed along with the expected sensitivities of les. Even more spectacular events could ing, and surface potential technology. sized mirrors with sub-angstrom polishing 9 Various possible gravitational wave sources are illustrat Compact binaries are among the most promising sources of gra The gravitational waves we expect to observe must be emitted BBO is a follow-on mission to LISA to probe the frequency regi jects. An extensive overview ofsummary. promising sources can be fou 3.1 Coalescing compact binaries based detectors like LIGO and VIRGO, andples the are planned the space-b coalescences of binary neutronbe stars or observed black from ho galaxy collisions andthe the centers subsequent of merge the galaxies.us A to census study of the a evolutioninteractions of significant in portion the different stellar population environments. of stars over cosm uniformity, and significant advances in thruster, discharg 3. Astrophysical sources This will require a considerablelized lasers, investment picoradian in pointing new capability, technolo multimeter LISA and Advanced LIGO. 2.4 Big Bang Observatory: BBO mary goal would be thefrequency study range of not primordial limited gravitational by wav LISA’s the scientific confusion program noise of from measuring comp wavesat from the any mergin redshift, and willinspiraling refine compact the objects. mapping of The space-time aro strain sensitivity of BBO Figure 7: Gravitational wave astronomy: now and future PoS(SUPERNOVA)025 Alicia M. Sintes retion from a disk, moderate tronomical observations. We dress several of LISA’s science tal tests of gravitational theory. tra-compact binaries) are binary onally split into three stages: in- prove) some of the untested pre- hich is particularly important for on how accurately the red-shifted edictions of General Relativity in tromagnetic counterparts, it is pos- major mergers of comparable mass , and how well the host galaxy of er values of the central objects will warf binaries emitting gravitational masses for many of these sources. of their formation: rapid spins will re mostly built by capturing smaller Galaxy, in the surrounding globular the inspiral and ringdown stages can on stars or black holes. LISA will ar cases. Combining the results from nteresting constraints on the equation pins and masses of the massive black lar populations in the bulge. erately relativistic inspiral phase to a combining the gravitational wave and odel also the merger phase of the coa- hniques in general relativity [37, 38]. ve a tremendous impact on one of the rem for black holes. In addition, since sensitive than the current searches [31], tly search for all the three stages of the black hole binaries themselves will pro- he distance-redshift relation from many ng the post-merger phase, wheren the a re- well-understood process resulting in 10 The observations of massive black hole coalescences will ad Low-mass binaries (also known as compact stellar-mass or ul The evolution of binary black hole coalescences is conventi Massive black holes will serve as laboratories for fundamen Verification binaries are the systems known from previous as Gravitational wave astronomy: now and future sulting black hole sheds irregularitiesringdown and radiation, deformations will i allow us to test the ’no-hair’ theo spiral, merger and ring down.be Gravitational waveforms accurately from computed byThe approximation/perturbation recent tec progress in numerical relativitylescence has of enabled binary to black m holesanalytical [39, 40, and 41] numerical for relativity some willbinary particul enable black-hole coalescence, to which coheren is significantlyand more improve the estimationLISA. of the parameters of the binary, w objectives. Firstly, detection of the signals from massive The measurement of their massesdictions and of spins General will Relativity. confirmthe (or We different dis should stages be of able binarynonlinear to evolution strong-field probe starting regime. with pr Detecting a and mod characterizi many of the massive black holesible mergers to are constrain likely the to values have ofelectromagnetic elec cosmological observations parameters [42]. by Inbinary black-hole particular, standard using sirens, t LISAof will be state able of to the put darkmass i energy of [43]. the The source errorthe and bars electromagnetic on the counterpart this luminosity is depend distance identified.outstanding are issues of This estimated present-day will cosmology. ha 3.2 Galactic Binaries vide direct observations of the black holes. Measuring the s holes will give us valuableimply information that about much the mechanism ofspins the imply black building the holes massive mass blackblack were holes holes by and built a the up sequence low of by spinsobjects imply gas coming that acc from massive random black holes directions. a also Knowing enable the more paramet accurate studies of the dynamics of the stel systems containing white dwarfs,be naked able helium to detect stars, suchclusters. neutr binaries The if most they common sources are arewave located signals expected within to of our be nearly white-d constant frequency and amplitude. know sky positions and approximate periods, distances, and PoS(SUPERNOVA)025 (solar 6 Alicia M. Sintes of the LISA mission because io of the mass of the inspiraling r geometry predicted by general s the pressure sustained through 10 000 individual compact binary esulting compact objects (neutron SA will be seen by optical follow- ill provide a unique map of ultra- he operation of the instrument, as eutron-star or white-dwarf captures, s in white dwarfs in particular. In y capture objects from the clouds of tional radiation. Other objects may ome from seeing the signals cut off lack holes that have, by chance, been round the central black holes. The first encounter with the hole to place chastic foreground produced by tens ars that have been tidally stripped by l indicate that the central object is not ass of 10 (solar mass) into a 10 his population, largely inaccessible to t-like objects orbiting the central hole tral hole by the evolution of giant stars ven hundreds of thousands of cycles, resented among the EMRI population. emnant in a neutron star or black hole. es that have come too close to the hole omagnetic signals it will be possible to c new physics. s theorems of Einstein’s theory. Direct d the holes. From this phase information of fundamental physics. For example, by t the formation and evolution of compact oss the horizon. 11 or smaller. Because they are more massive, black 4 − The collapse of a massive star, after gravitation overwhelm EMRIs figure among the principal fundamental-physics goals Supermassive black holes at the center of galaxies regularl EMRIs are Extreme Mass Ratio Inspiral sources, where the rat It is expected that LISA will detect and characterize around 3.4 Stellar collapse, supernovae and gamma-ray bursts mass) supermassive black hole. their signals contain richphase information evolution about of the theirreflect geometry signals, in a lasting detail the for near-geodesic thousands orbitswe they or expect follow e aroun to measure howrelativity closely [44], the geometry and matches thereby theevidence test Ker of the the black-hole existence uniquenes ofas a they horizon cross in the the horizon. spacetime Ifmassive they black will do hole; c not explaining what cut it off, then is that will wil require exoti nuclear burning, results in a supernovae explosion and the r holes sink to the centerAlso of because star of clusters their mass and they will canso be be the seen over-rep typical further expected away system than is n a stellar black hole with a m comparing the arrival times ofplace the improved gravitational bounds and on the electr mass of the graviton [45]. 3.3 Massive black hole captures systems, as well as establishof an millions accurate of estimate binaries of incompact the our binaries. sto Galaxy. The gravitational The wave measurementselectromagnetic resolved of detectors, systems t will w provide information abou binaries in general andaddition, the up physics to 10% of of mass theups, white transfer allowing dwarfs for and systems interesting observed tide cross-comparisons by and LI tests stars surrounding them. Many of these aredeflected compact onto stars orbits and b close enoughthem to the into black a hole bound for orbit, their have through been the captured loss by of tidaland energy effects: been to compact-object disrupted gravita binari by tidalthe forces; central compact hole; cores or black of holes giant thatsuch st have as formed those near seen the cen near thestars, central black hole holes, in white the dwarfs) Milkyuntil would Way. their then The losses survive r to as gravitational poin radiation send them acr well as a strong test of General Relativity. object to that of the central black hole is 10 Gravitational wave astronomy: now and future Observation of these known binaries will provide a check of t PoS(SUPERNOVA)025 , a are 5 26 − 10 . Searches 7 × − 4 Alicia M. Sintes ∼ 0 h s low as tron star will result in gravita- nals that are short in time. In bursts. The observation of the y targets in the high-frequency ological background of gravita- ous they are: the spin down rates urces of short gamma-ray bursts, entury per galaxy). This violent ore extensive searches are ongoing computers worldwide and currently asily observed. The spin down must ute to a better understanding of the onditions of density, temperature and art by the Einstein@Home project mma-ray bursts. lem. n-down limit promises to be well and ith some assumptions, place an upper l be visible with the current generation so general burst search templates need s, it seems unlikely that more than two ars are highly magnetized objects, but sar ellipticity as low as 10 cient mass dynamics to be a source of a radically new window to explore such m collapse to compact object formation rom the final merger of neutron star or ore difficult and indeed represent a mas- me, but relatively large in amplitude. esting would be coincident observations on star population in the galaxy, we have veform for most of these types of events ng neutron stars, or kinks and cusps on 12 Coalescing compact binaries are currently believed to be so Rapidly spinning neutron stars, or pulsars, are the other ke Although any departure from axial symmetry in a spinning neu Other possible sources may also produce intense gravity sig Using the LIGO S5 data, limits on the strain signal strength a http://einstein.phys.uwm.edu Finally, a variety of cosmological scenarios predict a cosm 5 gravitational waves. However the physics of theis process fro not well understoodexplosion and will produce such a events burst signal, are one rare that is (several short per in ti addition c to supernovae, there couldblack be hole burst-like binary signals systems, f instabilities in nascent rotati to be employed [29, 30]. and supernova explosions togravitational be waves the expected sources from ofprocesses such long leading events gamma-ray to gamma-ray will bursts. contrib of Particularly neutrinos inter and gravitational waves from supernovae and ga 3.5 Spinning neutron stars band: they are cosmic laboratories ofmagnetic fields. matter under The gravitational extreme wave c detectors willphenomena. open Gravitational wave astronomy: now and future The core collapse, if it is sufficiently asymmetric, has suffi cosmic strings. Unfortunately, the exactare gravitational not wa well-known (the string waveform is, in fact, known), tional radiation, and despite having alittle fair idea idea how of smooth the they neutr are andof therefore whether detectors. any We wil can however makeof a pulsars fair (radio guess at or how X-raybe mountain loud at spinning least neutron partially stars) dueif are to we magnetic e allocate dipole all braking, we aslimit see puls on to the gravitational likely radiation mass we quadrupole of can,or each three w pulsar. known Doing radio thi pulsars could[26]. be The seen most right likely now, though candidate m istruly the broken Crab with pulsar, current whose observational spi sensitivities. achieved for some pulsars. This correspondsfor to gravitational limits waves on from pul radio quiet neutron stars are m sive computational challenge [24, 32]. This has been met in p BOINC-based screensaver actively running on around 100delivering 000 about 80 teraflops of processing power to the prob 3.6 Stochastic background PoS(SUPERNOVA)025 ] Alicia M. Sintes tion to give this talk. I am also the Government of the Balearic s in regions and at energy scales , eds. F.A. Rasio & I.H. Stairs (Proc. aboration for help, and the support ojects FPA-2007-60220, HA2007- e Planck era and would be a good d be extracted through a correlation xample [25, 27, 28]). Measuring the st models the predicted amplitude of arXiv:astro-ph/0407149 owave background. This would seem itations of our universe, regarded as a flation, excitations of scalar fields aris- s. b: At. Mol. Opt Phys. 38, S497 pt. 10, 2495 he current LIGO detectors. If detectable h Lab of Electronics 105, 54 berichte der physikalish-mathematischen berichte der physikalish-mathematischen , ed. S.W. Hawking & W. Israel (Cambridge U. 13 “Binary Radio Pulsars” “300 Years of Gravitation” 2001, Class. Quantum Grav. 19, 1889 2005, Phys. Rev. Lett. 94, 241101 2006 Class. Quantum Grav. 23, S57 et al. et al. et al. Klasse, 688 Press: Cambridge, UK) Aspen Conference, ASP Conf. Series, Vol 328, p.25, USA) [ Klasse, 154 I would like to thank the organizing committee for the invita [1] Einstein, A. 1916, Preuss. Akad. Wiss. Berlin, Sitzungs [7] Thorne, K.S. 1987, in [2] Einstein, A. 1918, Preuss. Akad. Wiss. Berlin, Sitzungs [8] Hough, J., Rowan, S. and Sathyaprakash, B.S. 2005, J. Phy [9] Weber, J. 1960, Phys. Rev. 117, 306 [3] Hulse, R. A. and Taylor, J.[4] H. 1974, Astrophys. Hulse, J. R. 191, A. L59 and Taylor, J.[5] H. 1975, Astrophys. Hulse, J. R. 195, A. L51 and Taylor, J.[6] H. 1975, Astrophys. Weisberg, J.M. 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