Science.gov

Sample records for black hole jets

  1. Boosting jet power in black hole spacetimes.

    PubMed

    Neilsen, David; Lehner, Luis; Palenzuela, Carlos; Hirschmann, Eric W; Liebling, Steven L; Motl, Patrick M; Garrett, Travis

    2011-08-02

    The extraction of rotational energy from a spinning black hole via the Blandford-Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux.

  2. Boosting jet power in black hole spacetimes

    PubMed Central

    Neilsen, David; Lehner, Luis; Palenzuela, Carlos; Hirschmann, Eric W.; Liebling, Steven L.; Motl, Patrick M.; Garrett, Travis

    2011-01-01

    The extraction of rotational energy from a spinning black hole via the Blandford–Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux. PMID:21768341

  3. Dual jets from binary black holes.

    PubMed

    Palenzuela, Carlos; Lehner, Luis; Liebling, Steven L

    2010-08-20

    The coalescence of supermassive black holes--a natural outcome when galaxies merge--should produce gravitational waves and would likely be associated with energetic electromagnetic events. We have studied the coalescence of such binary black holes within an external magnetic field produced by the expected circumbinary disk surrounding them. Solving the Einstein equations to describe black holes interacting with surrounding plasma, we present numerical evidence for possible jets driven by these systems. Extending the process described by Blandford and Znajek for a single, spinning black hole, the picture that emerges suggests that the electromagnetic field extracts energy from the orbiting black holes, which ultimately merge and settle into the standard Blandford-Znajek scenario. Emissions along these jets could potentially be observable at large distances.

  4. Jets in black-hole binaries

    NASA Astrophysics Data System (ADS)

    Zdziarski, Andrzej

    2016-07-01

    I will review selected aspects of observations and theory of jets in black-hole binaries. The radio and gamma-ray emission of jets differs significantly between the low and high-mass X-ray binaries, which appears to be due jet-wind interaction (in particular, formation of recollimation shocks) in the latter. Also, both radio and X-ray emission of the jets can be significantly absorbed in the stellar wind of the donors in high-mass binaries. I will also review the theory of radiative processes in jets, their contributions to broad-band spectra, estimates of the jet power, the role of black-hole spin in powering jets, and the possibility that the base of the jet is the main source of X-ray emission (the lamppost model).

  5. Maximum spin of black holes driving jets

    NASA Astrophysics Data System (ADS)

    Benson, Andrew J.; Babul, Arif

    2009-08-01

    Unbound outflows in the form of highly collimated jets and broad winds appear to be a ubiquitous feature of accreting black hole systems. The most powerful jets are thought to derive a significant fraction, if not the majority, of their power from the rotational energy of the black hole. Whatever the precise mechanism that causes them, these jets must, therefore, exert a braking torque on the black hole. Consequently, we expect jet production to play a significant role in limiting the maximum spin attainable by accreting black holes. We calculate the spin-up function - the rate of change of black hole spin normalized to the black hole mass and accretion rate - for an accreting black hole, accounting for this braking torque. We assume that the accretion flow on to a Kerr black hole is advection-dominated (ADAF) and construct easy-to-use analytic fits to describe the global structure of such flows based on the numerical solutions of Popham & Gammie. We find that the predicted black hole spin-up function depends only on the black hole spin and dimensionless parameters describing the accretion flow. Using recent relativistic magnetohydrodynamical (MHD) numerical simulation results to calibrate the efficiency of angular momentum transfer in the flow, we find that an ADAF flow will spin a black hole up (or down) to an equilibrium value of about 96 per cent of the maximal spin value in the absence of jets. Combining our ADAF system with a simple model for jet power, we demonstrate that an equilibrium is reached at approximately 93 per cent of the maximal spin value, as found in the numerical simulation studies of the spin-up of accreting black holes, at which point the spin-up of the hole by accreted material is balanced by the braking torque arising from jet production. The existence of equilibrium spin means that optically dim active galactic nuclei (AGNs) that have grown via accretion from an advection-dominated flow will not be maximally rotating. It also offers a

  6. Electromagnetic jets from stars and black holes

    NASA Astrophysics Data System (ADS)

    Gralla, Samuel E.; Lupsasca, Alexandru; Rodriguez, Maria J.

    2016-02-01

    We present analytic force-free solutions modeling rotating stars and black holes immersed in the magnetic field of a thin disk that terminates at an inner radius. The solutions are exact in flat spacetime and approximate in Kerr spacetime. The compact object produces a conical jet whose properties carry information about its nature. For example, the jet from a star is surrounded by a current sheet, while that of a black hole is smooth. We compute an effective resistance in each case and compare to the canonical values used in circuit models of energy extraction. These solutions illustrate all of the basic features of the Blandford-Znajek process for energy extraction and jet formation in a clean setting.

  7. Scale-invariant radio jets and varying black hole spin

    NASA Astrophysics Data System (ADS)

    Mościbrodzka, M.; Falcke, H.; Noble, S.

    2016-11-01

    Context. Compact radio cores associated with relativistic jets are often observed in both active galactic nuclei and X-ray binaries. Their radiative properties follow some general scaling laws that primarily depend on their masses and accretion rates. However, it has been suggested that black hole spin can also strongly influence the power and radio flux of these. Aims: We attempt to estimate the dependency of the radio luminosity of steady jets launched by accretion disks on black hole mass, accretion rate, and spin using numerical simulations. Methods: We make use of three-dimensional general relativistic magnetohydrodynamical simulations of accretion disks around low-luminosity black holes in which the jet radio emission is produced by the jet sheath. Results: We find that the radio flux increases roughly by a factor of 6 as the black hole spin increases from a∗ ≈ 0 to a∗ = 0.98. This is comparable to the increase in accretion power with spin, meaning that the ratio between radio jet and accretion power hardly changes. Although our jet spine power scales as expected for the Blandford-Znajek process, the dependency of jet radio luminosity on the black hole spin is somewhat weaker. Also weakly rotating black holes can produce visible radio jets. The overall scaling of the radio emission with black hole mass and accretion rate is consistent with the scale-invariant analytical models used to explain the fundamental plane of black hole activity. Spin does not introduce a significant scatter in this model. Conclusions: The jet-sheath model can describe well-resolved accreting systems, such as Sgr A* and M 87, as well as the general scaling behavior of low-luminosity black holes. Hence the model should be applicable to a wide range of radio jets in sub-Eddington black holes. The black hole spin has an effect on the production of visible radio jet, but it may not be the main driver to produce visible radio jets. An extension of our findings to powerful quasars

  8. Superluminal Jets and Other Properties of Black Holes Binaries

    NASA Technical Reports Server (NTRS)

    Harmon, Alan

    1997-01-01

    Discoveries in the past few years of radio jets in Galactic black hole candidates have provided a link between active galactic nuclei (AGNS) and the compact stars in binary systems. The availability of binary systems relatively close by is an opportunity to learn about the jet production mechanism on a timescale a million times shorter than that of an AGN. Evidence is clearly seen of correlated high energy X-ray and gamma ray emission to radio emission from jets, linking the accretion and jet production mechanisms. objects such as GRS 1915+105, GRO J1655-40 and Cyg X-3 show striking properties which distinguish them from other black hole candidates. Our theoretical understanding of these systems is still in the formative stages. I review some of the most recent multiwavelength data and point out questions raised by these observations.

  9. JETS FROM TIDAL DISRUPTIONS OF STARS BY BLACK HOLES

    SciTech Connect

    Krolik, Julian H.; Piran, Tsvi E-mail: tsvi@phys.huji.ac.il

    2012-04-10

    Tidal disruption of main-sequence stars by black holes has generally been thought to lead to a signal dominated by UV emission. If, however, the black hole spins rapidly and the poloidal magnetic field intensity on the black hole horizon is comparable to the inner accretion disk pressure, a powerful jet may form whose luminosity can easily exceed the thermal UV luminosity. When the jet beam points at Earth, its non-thermal luminosity can dominate the emitted spectrum. The thermal and non-thermal components decay differently with time. In particular, the thermal emission should remain roughly constant for a significant time after the period of maximum accretion, beginning to diminish only after a delay, whereas after the peak accretion rate, the non-thermal jet emission decays, but then reaches a plateau. Both transitions are tied to a characteristic timescale t{sub Edd} at which the accretion rate falls below Eddington. Making use of this timescale in a new parameter-inference formalism for tidal disruption events with significant emission from a jet, we analyze the recent flare source Swift J2058. It is consistent with an event in which a main-sequence solar-type star is disrupted by a black hole of mass {approx}4 Multiplication-Sign 10{sup 7} M{sub Sun }. The beginning of the flat phase in the non-thermal emission from this source can possibly be seen in the late-time light curve. Optical photometry over the first {approx_equal} 40 days of this flare is also consistent with this picture, but is only weakly constraining because the bolometric correction is very uncertain. We suggest that future searches for main-sequence tidal disruptions use methods sensitive to jet radiation as well as to thermal UV radiation.

  10. The Formation of Relativistic Jets from Kerr Black Holes

    NASA Technical Reports Server (NTRS)

    Nishikawa, K.-I.; Richardson, G.; Preece, R.; Hardee, P.; Koide, S.; Shibata, K.; Kudoh, T.; Sol, H.; Fishman, G. J.

    2003-01-01

    We have performed the first fully three-dimensional general relativistic magnetohydrodynamics (GRMHD) simulation for Schwarzschild and Kerr black holes with a free falling corona and thin accretion disk. The initial simulation results with a Schwarzschild metric show that a jet is created as in the previous axisymmetric simulations with mirror symmetry at the equator. However, the time to form the jet is slightly longer than in the 2-D axisymmetric simulation. We expect that the dynamics of jet formation are modified due to the additional freedom in the azimuth dimension without axisymmetry with respect to the Z axis and reflection symmetry respect to the equatorial plane. The jet which is initially formed due to the twisted magnetic fields and shocks becomes a wind at the later time. The wind flows out with a much wider angle than the initial jet. The twisted magnetic fields at the earlier time were untwisted and less pinched. The accretion disk became thicker than the initial condition. Further simulations with initial perturbations will provide insights for accretion dynamics with instabilities such as magneto-rotational instability (MRI) and accretion-eject instability (AEI). These instabilities may contribute to variabilities observed in microquasars and AGN jets.

  11. Observable acceleration of jets by a Kerr black hole

    NASA Astrophysics Data System (ADS)

    Gariel, J.; Santos, N. O.; Wang, Anzhong

    2017-03-01

    In the framework of a model based on the gravitational field of the Kerr black hole, we turn to investigate the kinematic behavior of extragalactic jets. We analytically calculate the observable velocities and accelerations along any geodesic. Then, by numerical calculations, we apply our results to a geodesic, typical of the M87 jet, and probe our results by confrontation to recent observations. A transition from non-relativistic to ultrarelativistic speeds at subparsec scale is highlighted. This transition comes sooner and more abruptly than in models based on magnetic paradigm, which indicates that we need a weaker magnetic field to explain observed synchrotron radiation. We attribute the ejection phenomenon to the repulsive effect of the gravitomagnetic Kerr field.

  12. High Performance Simulations of Accretion Disk Dynamics and Jet Formations Around Kerr Black Holes

    NASA Technical Reports Server (NTRS)

    Nishikawa, Ken-Ichi; Mizuno, Yosuke; Watson, Michael

    2007-01-01

    We investigate jet formation in black-hole systems using 3-D General Relativistic Particle-In-Cell (GRPIC) and 3-D GRMHD simulations. GRPIC simulations, which allow charge separations in a collisionless plasma, do not need to invoke the frozen condition as in GRMHD simulations. 3-D GRPIC simulations show that jets are launched from Kerr black holes as in 3-D GRMHD simulations, but jet formation in the two cases may not be identical. Comparative study of black hole systems with GRPIC and GRMHD simulations with the inclusion of radiate transfer will further clarify the mechanisms that drive the evolution of disk-jet systems.

  13. Chasing the heaviest black holes of jetted active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Ghisellini, G.; Della Ceca, R.; Volonteri, M.; Ghirlanda, G.; Tavecchio, F.; Foschini, L.; Tagliaferri, G.; Haardt, F.; Pareschi, G.; Grindlay, J.

    2010-06-01

    We investigate the physical properties of 10 blazars at redshift greater than 2 detected in the 3-yr all-sky survey performed by the Burst Alert Telescope (BAT) on board the Swift satellite. We find that the jets of these blazars are among the most powerful known. Furthermore, the mass of their central black hole, inferred from the optical-ultraviolet bump, exceeds a few billions of solar masses, with accretion luminosities being a large fraction of the Eddington one. We compare their properties with those of the brightest blazars of the 3-month survey performed by the Large Area Telescope (LAT) on board the Fermi satellite. We find that the BAT blazars have more powerful jets, more luminous accretion discs and larger black hole masses than LAT blazars. These findings can be simply understood on the basis of the blazar sequence, which suggests that the most powerful blazars have a spectral energy distribution with a high-energy peak at MeV (or even sub-MeV) energies. This implies that the most extreme blazars can be found more efficiently in hard X-rays, rather than in the high-energy γ-ray band. We then discuss the implications of our findings for future missions, such as the New Hard X-ray Mission (NHXM) and especially the Energetic X-ray Imaging Survey Telescope (EXIST) mission which, during its planned 2-yr all-sky survey, is expected to detect thousands of blazars, with a few of them at z >~ 6.

  14. Radio Telescopes Zoom into a Black Hole's Jets

    NASA Video Gallery

    Centaurus A is a giant elliptical active galaxy 12 million light-years away. At its heart lies a black hole with a mass of 55 million suns. Now, the TANAMI project has provided the best-ever image ...

  15. THE RATE OF GAS ACCRETION ONTO BLACK HOLES DRIVES JET VELOCITY

    SciTech Connect

    King, Ashley L.; Miller, Jon M.; Gültekin, Kayhan; Reynolds, Mark; Bietenholz, Michael; Bartel, Norbert; Mioduszewski, Amy; Rupen, Michael

    2015-01-20

    Accreting black holes are observed to launch relativistic, collimated jets of matter and radiation. In some sources, discrete ejections have been detected with highly relativistic velocities. These particular sources typically have very high mass accretion rates, while sources lower knot velocities are predominantly associated with black holes with relatively low mass accretion rates. We quantify this behavior by examining knot velocity with respect to X-ray luminosity, a proxy for mass accretion rate onto the black hole. We find a positive correlation between the mass-scaled X-ray luminosity and jet knot velocity. In addition, we find evidence that the jet velocity is also a function of polar angle, supporting the ''spine-sheath'' model of jet production. Our results reveal a fundamental aspect of how accretion shapes mechanical feedback from black holes into their host environments.

  16. Relativistic Jets on all Scales in Accreting Black Holes: Contributions from Simbol-X

    NASA Astrophysics Data System (ADS)

    Corbel, Stéphane

    2009-05-01

    In the last several years, multiwavelength observations of accreting black holes have allowed a general characterisation of black holes properties as they evolve along the course of their outburst cycles. Relativistic jets, in their multiple forms, have profoundly impacted our perception and understanding of emission processes in these systems. In these Proceedings, I will highlight some possible contributions from Simbol-X related to jets in accreting sources.

  17. Relativistic Jets on all Scales in Accreting Black Holes: Contributions from Simbol-X

    SciTech Connect

    Corbel, Stephane

    2009-05-11

    In the last several years, multiwavelength observations of accreting black holes have allowed a general characterisation of black holes properties as they evolve along the course of their outburst cycles. Relativistic jets, in their multiple forms, have profoundly impacted our perception and understanding of emission processes in these systems. In these Proceedings, I will highlight some possible contributions from Simbol-X related to jets in accreting sources.

  18. A Universal Scaling for the Energetics of Relativistic Jets From Black Hole Systems

    NASA Technical Reports Server (NTRS)

    Nemmen, R. S.; Georganopoulos, M.; Guiriec, S.; Meyer, E. T.; Gehrels, N.; Sambruna, R. M.

    2013-01-01

    Black holes generate collimated, relativistic jets which have been observed in gamma-ray bursts (GRBs), microquasars, and at the center of some galaxies (active galactic nuclei; AGN). How jet physics scales from stellar black holes in GRBs to the supermassive ones in AGNs is still unknown. Here we show that jets produced by AGNs and GRBs exhibit the same correlation between the kinetic power carried by accelerated particles and the gamma-ray luminosity, with AGNs and GRBs lying at the low and high-luminosity ends, respectively, of the correlation. This result implies that the efficiency of energy dissipation in jets produced in black hole systems is similar over 10 orders of magnitude in jet power, establishing a physical analogy between AGN and GRBs.

  19. A universal scaling for the energetics of relativistic jets from black hole systems.

    PubMed

    Nemmen, R S; Georganopoulos, M; Guiriec, S; Meyer, E T; Gehrels, N; Sambruna, R M

    2012-12-14

    Black holes generate collimated, relativistic jets, which have been observed in gamma-ray bursts (GRBs), microquasars, and at the center of some galaxies [active galactic nuclei (AGN)]. How jet physics scales from stellar black holes in GRBs to the supermassive ones in AGN is still unknown. Here, we show that jets produced by AGN and GRBs exhibit the same correlation between the kinetic power carried by accelerated particles and the gamma-ray luminosity, with AGN and GRBs lying at the low- and high-luminosity ends, respectively, of the correlation. This result implies that the efficiency of energy dissipation in jets produced in black hole systems is similar over 10 orders of magnitude in jet power, establishing a physical analogy between AGN and GRBs.

  20. JET POWER AND BLACK HOLE SPIN: TESTING AN EMPIRICAL RELATIONSHIP AND USING IT TO PREDICT THE SPINS OF SIX BLACK HOLES

    SciTech Connect

    Steiner, James F.; McClintock, Jeffrey E.; Narayan, Ramesh

    2013-01-10

    Using 5 GHz radio luminosity at light-curve maximum as a proxy for jet power and black hole spin measurements obtained via the continuum-fitting method, Narayan and McClintock presented the first direct evidence for a relationship between jet power and black hole spin for four transient black hole binaries. We test and confirm their empirical relationship using a fifth source, H1743-322, whose spin was recently measured. We show that this relationship is consistent with Fe-line spin measurements provided that the black hole spin axis is assumed to be aligned with the binary angular momentum axis. We also show that, during a major outburst of a black hole transient, the system reasonably approximates an X-ray standard candle. We further show, using the standard synchrotron bubble model, that the radio luminosity at light-curve maximum is a good proxy for jet kinetic energy. Thus, the observed tight correlation between radio power and black hole spin indicates a strong underlying link between mechanical jet power and black hole spin. Using the fitted correlation between radio power and spin for the above five calibration sources, we predict the spins of six other black holes in X-ray/radio transient systems with low-mass companions. Remarkably, these predicted spins are all relatively low, especially when compared to the high measured spins of black holes in persistent, wind-fed systems with massive companions.

  1. Jet Power and Black Hole Spin: Testing an Empirical Relationship and Using it to Predict the Spins of Six Black Holes

    NASA Astrophysics Data System (ADS)

    Steiner, James F.; McClintock, Jeffrey E.; Narayan, Ramesh

    2013-01-01

    Using 5 GHz radio luminosity at light-curve maximum as a proxy for jet power and black hole spin measurements obtained via the continuum-fitting method, Narayan & McClintock presented the first direct evidence for a relationship between jet power and black hole spin for four transient black hole binaries. We test and confirm their empirical relationship using a fifth source, H1743-322, whose spin was recently measured. We show that this relationship is consistent with Fe-line spin measurements provided that the black hole spin axis is assumed to be aligned with the binary angular momentum axis. We also show that, during a major outburst of a black hole transient, the system reasonably approximates an X-ray standard candle. We further show, using the standard synchrotron bubble model, that the radio luminosity at light-curve maximum is a good proxy for jet kinetic energy. Thus, the observed tight correlation between radio power and black hole spin indicates a strong underlying link between mechanical jet power and black hole spin. Using the fitted correlation between radio power and spin for the above five calibration sources, we predict the spins of six other black holes in X-ray/radio transient systems with low-mass companions. Remarkably, these predicted spins are all relatively low, especially when compared to the high measured spins of black holes in persistent, wind-fed systems with massive companions.

  2. Black holes

    PubMed Central

    Brügmann, B.; Ghez, A. M.; Greiner, J.

    2001-01-01

    Recent progress in black hole research is illustrated by three examples. We discuss the observational challenges that were met to show that a supermassive black hole exists at the center of our galaxy. Stellar-size black holes have been studied in x-ray binaries and microquasars. Finally, numerical simulations have become possible for the merger of black hole binaries. PMID:11553801

  3. Black holes.

    PubMed

    Brügmann, B; Ghez, A M; Greiner, J

    2001-09-11

    Recent progress in black hole research is illustrated by three examples. We discuss the observational challenges that were met to show that a supermassive black hole exists at the center of our galaxy. Stellar-size black holes have been studied in x-ray binaries and microquasars. Finally, numerical simulations have become possible for the merger of black hole binaries.

  4. Searching for Intermediate Mass Black Holes in Dwarf Galaxies using Jet Emission

    NASA Astrophysics Data System (ADS)

    Musaeva, Ayna; Koribalski, Baerbel; Sadler, Elaine; Farrell, Sean

    2014-10-01

    Supermassive black holes (SMBHs) are the central engines of active galactic nuclei and lie at the heart of many large galaxies, including our own Milky Way. If massive black holes exist in dwarf galaxies, these galaxies are expected to contain intermediate mass black holes (IMBHs) with masses in the range between 100 and 100,000 solar masses. Only a handful of IMBH candidates have been found in dwarf galaxies, which suggests that IMBHs may not be as common as SMBHs or they are more difficult to detect. For accreting black holes, one way to estimate their mass is by the fundamental plane relation between their X-ray and radio luminosities at 5 GHz. The radio emission comes from relativistic jets of a black hole accreting at a low fraction of the Eddington limit. We have identified several X-ray sources which are candidates for an accreting black hole in the central part of three nearby dwarf galaxies. We request 5 GHz Australia Telescope Compact Array (ATCA) observations of these X-ray sources in order to search for radio counterparts and identify IMBH candidates. The ~2’’ spatial resolution of ATCA with a 6-km array configuration allows us to make sure X-ray and radio emission originates from the same source, and a broad bandwidth of ~4 GHz makes ATCA an ideal instrument for detecting the radio counterparts of the X-ray sources, confirming the radio emission is consistent with jets, and estimating the black hole masses.

  5. Jet-launching structure resolved near the supermassive black hole in M87.

    PubMed

    Doeleman, Sheperd S; Fish, Vincent L; Schenck, David E; Beaudoin, Christopher; Blundell, Ray; Bower, Geoffrey C; Broderick, Avery E; Chamberlin, Richard; Freund, Robert; Friberg, Per; Gurwell, Mark A; Ho, Paul T P; Honma, Mareki; Inoue, Makoto; Krichbaum, Thomas P; Lamb, James; Loeb, Abraham; Lonsdale, Colin; Marrone, Daniel P; Moran, James M; Oyama, Tomoaki; Plambeck, Richard; Primiani, Rurik A; Rogers, Alan E E; Smythe, Daniel L; SooHoo, Jason; Strittmatter, Peter; Tilanus, Remo P J; Titus, Michael; Weintroub, Jonathan; Wright, Melvyn; Young, Ken H; Ziurys, Lucy M

    2012-10-19

    Approximately 10% of active galactic nuclei exhibit relativistic jets, which are powered by the accretion of matter onto supermassive black holes. Although the measured width profiles of such jets on large scales agree with theories of magnetic collimation, the predicted structure on accretion disk scales at the jet launch point has not been detected. We report radio interferometry observations, at a wavelength of 1.3 millimeters, of the elliptical galaxy M87 that spatially resolve the base of the jet in this source. The derived size of 5.5 ± 0.4 Schwarzschild radii is significantly smaller than the innermost edge of a retrograde accretion disk, suggesting that the M87 jet is powered by an accretion disk in a prograde orbit around a spinning black hole.

  6. From Cradle To Grave: Chandra Discovers The History Of Black Hole X-Ray Jets

    NASA Astrophysics Data System (ADS)

    2002-10-01

    For the first time, astronomers have tracked the life cycle of X-ray jets from a black hole. A series of images from NASA's Chandra X-ray Observatory has revealed that as the jets evolved, they traveled at near light speed for several years before slowing down and fading. "Watching these jets slow down and disappear is like watching a time-lapse movie of the rise and fall of the Bronze Age," said Stephane Corbel of the University of Paris VII and the French Atomic Energy Commission in Saclay, lead author of a paper in the October 4th issue of the journal Science. "Since the jets came from a stellar black hole in our galaxy, we watched in a few years developments that would have taken thousands of years to occur around a supermassive black hole in a distant galaxy." Astronomers have been using Chandra and radio telescopes to observe two opposing jets of high-energy particles emitted following an outburst, first detected in 1998 by NASA's Rossi X-ray Timing Explorer, from the double-star system XTE J1550-564. The X-ray jets, which require a continuous source of trillion-volt electrons to remain bright, were observed moving at about half the speed of light. Four years later, they are now more than three light years apart and slowing down. One of the jets has recently been observed to fade. XTE J1550-564 Time-Lapse Movie XTE J1550-564 Time-Lapse Movie "The ejection of jets from stellar and supermassive black holes is a common occurrence in the universe, so it is extremely important to understand the process," said John Tomsick of the University of California, San Diego, and author of an Astrophysical Journal paper scheduled for January 2003 publication describing the research. "For the first time, we have observed a jet from the initial explosion until it slowed and faded." The observations indicate that one jet, the eastern jet, is moving along a line tilted toward the Earth whereas the western jet is pointed away from the Earth. This alignment explains why the

  7. Jet signatures of black holes: From Sgr A* to active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Britzen, S.; Eckart, A.; Lämmerzahl, C.; Roland, J.; Brockamp, M.; Hackmann, E.; Kunz, J.; Macias, A.; Malchow, R.; Sabha, N.; Shahzamanian, B.

    2015-06-01

    Detailed and long-term VLBI (Very Long Baseline Interferometry) studies of the variable jets of supermassive black holes helps us to understand the emission processes of these fascinating phenomena. When observed and traced precisely, jet component kinematics reveals details about the potential motion of the jet base. Following this motion over decades with VLBI monitoring reveals - in some cases - the signatures of precession. While several processes can cause precession, the most likely cause seems to be a supermassive binary black hole in the central region of the AGN. We present examples of the analysis of high-resolution VLBI observations which provides us with insight into the physics of these objects and reveals evidence for the presence of double black hole cores. EHT (Event Horizon Telescope) observations will probably soon tell us more about the jet origin and launching mechanism at the very centers of nearby active galactic nuclei. An important question to be addressed by the EHT and related observations will be whether Sgr A\\star, the supermassive black hole in the Galactic Center, has a jet as well.

  8. ON THE ROLE OF THE ACCRETION DISK IN BLACK HOLE DISK-JET CONNECTIONS

    SciTech Connect

    Miller, J. M.; Reis, R. C.; Pooley, G. G.; Fabian, A. C.; Cackett, E. M.; Nowak, M. A.; Pottschmidt, K.; Wilms, J.

    2012-09-20

    Models of jet production in black hole systems suggest that the properties of the accretion disk-such as its mass accretion rate, inner radius, and emergent magnetic field-should drive and modulate the production of relativistic jets. Stellar-mass black holes in the 'low/hard' state are an excellent laboratory in which to study disk-jet connections, but few coordinated observations are made using spectrometers that can incisively probe the inner disk. We report on a series of 20 Suzaku observations of Cygnus X-1 made in the jet-producing low/hard state. Contemporaneous radio monitoring was done using the Arcminute MicroKelvin Array radio telescope. Two important and simple results are obtained: (1) the jet (as traced by radio flux) does not appear to be modulated by changes in the inner radius of the accretion disk and (2) the jet is sensitive to disk properties, including its flux, temperature, and ionization. Some more complex results may reveal aspects of a coupled disk-corona-jet system. A positive correlation between the reflected X-ray flux and radio flux may represent specific support for a plasma ejection model of the corona, wherein the base of a jet produces hard X-ray emission. Within the framework of the plasma ejection model, the spectra suggest a jet base with v/c {approx_equal} 0.3 or the escape velocity for a vertical height of z {approx_equal} 20 GM/c {sup 2} above the black hole. The detailed results of X-ray disk continuum and reflection modeling also suggest a height of z {approx_equal} 20 GM/c {sup 2} for hard X-ray production above a black hole, with a spin in the range 0.6 {<=} a {<=} 0.99. This height agrees with X-ray time lags recently found in Cygnus X-1. The overall picture that emerges from this study is broadly consistent with some jet-focused models for black hole spectral energy distributions in which a relativistic plasma is accelerated at z = 10-100 GM/c {sup 2}. We discuss these results in the context of disk-jet connections

  9. Jets Spout Far Closer to Black Hole Than Thought, Scientists Say

    NASA Astrophysics Data System (ADS)

    2004-01-01

    Scientists at the Massachusetts Institute of Technology, taking advantage of multiple unique views of black hole particle jets over the course of a year with NASA's Chandra X-ray Observatory, have assembled a "picture" of the region that has revealed several key discoveries. They have found that the jets may be originating five times closer to the black hole than previously thought; they see in better detail how these jets change with time and distance from the black hole; and they could use this information as a new technique to measure black hole mass. Presented today in a press conference at the meeting of the American Astronomical Society in Atlanta, the observation will ultimately help solve the mystery of the great cosmic contradiction, in which black holes, notorious for pulling matter in, somehow manage to also shoot matter away in particle jets moving close to the speed of light. The observation is of a familiar source named SS 433 -- a binary star system within our Galaxy in the constellation Aquila, the Eagle, about 16,000 light years away. The black hole and its companion are about two-thirds closer to each other than the planet Mercury is to the Sun. The jets shoot off at 175 million miles per hour, 26 percent of light speed. "The high-speed jets in nearby SS 433 may be caused by the same mechanisms as the powerful outflows in the most distant and much more massive black holes, such as quasars," said Laura Lopez, an undergraduate student at MIT and lead author on a paper about the result. "SS 433 provides a nice local laboratory to study the formation of and conditions in relativistic jets." Dr. Herman Marshall, Ms. Lopez's research supervisor, led the investigation. Matter from the companion star pours into the black hole via a swirling accretion disk, much like water down a drain. Black hole particles jets are thought to be produced as some of the matter encounters strong magnetic fields close to the black hole. SS 433 is angled in such a way that

  10. THE DISK-WIND-JET CONNECTION IN THE BLACK HOLE H 1743-322

    SciTech Connect

    Miller, J. M.; King, A. L.; Raymond, J.; Fabian, A. C.; Reynolds, C. S.; Kallman, T. R.; Cackett, E. M.; Van der Klis, M.; Steeghs, D. T. H.

    2012-11-01

    X-ray disk winds are detected in spectrally soft, disk-dominated phases of stellar-mass black hole outbursts. In contrast, compact, steady, relativistic jets are detected in spectrally hard states that are dominated by non-thermal X-ray emission. Although these distinctive outflows appear to be almost mutually exclusive, it is possible that a disk wind persists in hard states but cannot be detected via X-ray absorption lines owing to very high ionization. Here, we present an analysis of a deep, 60 ks Chandra/HETGS observation of the black hole candidate H 1743-322 in the low/hard state. The spectrum shows no evidence of a disk wind, with tight limits, and within the range of ionizing flux levels that were measured in prior Chandra observations wherein a wind was clearly detected. In H 1743-322, at least, disk winds are actually diminished in the low/hard state, and disk winds and jets are likely state dependent and anti-correlated. These results suggest that although the launching radii of winds and jets may differ by orders of magnitude, they may both be tied to a fundamental property of the inner accretion flow, such as the mass accretion rate and/or the magnetic field topology of the disk. We discuss these results in the context of disk winds and jets in other stellar-mass black holes, and possible launching mechanisms for black hole outflows.

  11. Magnetorotatioal Collapse of Supermassive Stars: Black Hole Formation and Jets

    NASA Astrophysics Data System (ADS)

    Sun, Lunan; Paschalidis, Vasileios; Ruiz, Milton; Shapiro, Stuart

    2017-01-01

    We perform magnetohydrodynamic simulations in full general relativity of the collapse of radially unstable, uniformly rotating, massive stars to black holes. The stars spin at the mass-shedding limit, account for magnetic fields and obey a Γ = 4/3 EOS. The calculations lift the restriction of axisymmetry imposed in previous simulations. Our simulations model the direct collapse of supermassive stars to supermassive BHs (>=104M⊙) at high cosmological redshifts, which may explain the appearance of supermassive BHs and quasars by z 7. They also crudely model the collapse of massive Pop III stars to massive BHs, which could power some of the long gamma-ray bursts observed by FERMI and SWIFT at z 6-8. We analyze the properties of the electromagnetic and gravitational wave signatures of these events and discuss the detectability of such multimessenger sources.

  12. Binary Black Holes, Accretion Disks and Relativistic Jets: Photocenters of Nearby AGN and Quasars

    NASA Technical Reports Server (NTRS)

    Wehrle, Ann E.; Jones, Dayton L.; Meier, David L.; Piner, B. Glenn; Unwin, Stephen C.

    2004-01-01

    One of the most challenging questions in astronomy today is to understand the origin, structure, and evolution of the central engines in the nuclei of quasars and active galaxies (AGNs). The favoured theory involves the activation of relativistic jets from the fueling of a supermassive black hole through an accretion disk. In some AGN an outer optically thick, dusty torus is seen orbiting the black hole system. This torus is probably related to an inner accretion disk - black hole system that forms the actual powerhouse of the AGN. In radio-loud AGN two oppositely-directed radio jets are ejected perpendicular to the torus/disk system. Although there is a wealth of observational data on AGN, some very basic questions have not been definitively answered. The Space Interferometry Mission (SIM) will address the following three key questions about AGN. 1) Does the most compact optical emission from an AGN come from an accretion disk or from a relativistic jet? 2) Does the separation of the radio core and optical photocenter of the quasars used for the reference frame tie, change on the timescales of their photometric variability, or is the separation stable at the level of a few microarcseconds? 3) Do the cores of galaxies harbor binary supermassive black holes remaining from galaxy mergers? It is not known whether such mergers are common, and whether binaries would persist for a significant time.

  13. Neutron Production in Black Hole Coronae and Proton Loading of Jets

    NASA Astrophysics Data System (ADS)

    Vila, Gabriela S.; Vieyro, Florencia L.; Romero, Gustavo E.

    2014-03-01

    We study the production of neutrons in the corona of an accreting black hole through the interaction of locally accelerated protons with matter and radiation. A fraction of these neutrons may escape and penetrate into the base of the jet, later decaying into protons. This is a possible mechanism for loading Poynting-dominated outflows with baryons. We characterize the spatial and energy distribution of neutrons in the corona and that of the protons injected in the jet by neutron decay. We assess the contribution of these protons to the radiative spectrum of the jet. We also investigate the fate of the neutrons that escape the corona into the external medium.

  14. Megaparsec relativistic jets launched from an accreting supermassive black hole in an extreme spiral galaxy

    SciTech Connect

    Bagchi, Joydeep; Vivek, M.; Srianand, Raghunathan; Gopal-Krishna; Vikram, Vinu; Hota, Ananda; Biju, K. G.; Sirothia, S. K.; Jacob, Joe

    2014-06-20

    The radio galaxy phenomenon is directly connected to mass-accreting, spinning supermassive black holes found in the active galactic nuclei. It is still unclear how the collimated jets of relativistic plasma on hundreds to thousands of kiloparsec scales form and why they are nearly always launched from the nuclei of bulge-dominated elliptical galaxies and not flat spirals. Here we present the discovery of the giant radio source J2345–0449 (z = 0.0755), a clear and extremely rare counterexample where relativistic jets are ejected from a luminous and massive spiral galaxy on a scale of ∼1.6 Mpc, the largest known so far. Extreme physical properties observed for this bulgeless spiral host, such as its high optical and infrared luminosity, large dynamical mass, rapid disk rotation, and episodic jet activity, are possibly the results of its unusual formation history, which has also assembled, via gas accretion from a disk, its central black hole of mass >2 × 10{sup 8} M {sub ☉}. The very high mid-IR luminosity of the galaxy suggests that it is actively forming stars and still building a massive disk. We argue that the launch of these powerful jets is facilitated by an advection-dominated, magnetized accretion flow at a low Eddington rate onto this unusually massive (for a bulgeless disk galaxy) and possibly fast spinning central black hole. Therefore, J2345–0449 is an extremely rare, unusual galactic system whose properties challenge the standard paradigms for black hole growth and the formation of relativistic jets in disk galaxies. Thus, it provides fundamental insight into accretion disk-relativistic jet coupling processes.

  15. Jet Signatures in the Spectra of Accreting Black Holes

    NASA Astrophysics Data System (ADS)

    O' Riordan, Michael; Pe'er, Asaf; McKinney, Jonathan C.

    2016-03-01

    Jets are observed as radio emission in active galactic nuclei and during the low/hard state in X-ray binaries (XRBs), but their contribution at higher frequencies has been uncertain. We study the dynamics of jets in XRBs using the general-relativistic magnetohydrodynamic code HARM. We calculate the high-energy spectra and variability properties using a general-relativistic radiative transport code based on grmonty. We find the following signatures of jet emission: (i) a significant γ-ray peak above ˜1022 Hz, (ii) a break in the optical/UV spectrum, with a change from ν {L}ν ˜ {ν }0 to ν {L}ν ˜ ν , followed by another break at higher frequencies where the spectrum roughly returns to ν {L}ν ˜ {ν }0, and (iii) a pronounced synchrotron peak near or below ˜1014 Hz indicates that a significant fraction of any observed X-ray emission originates in the jet. We investigate the variability during a large-scale magnetic field inversion in which the Blandford-Znajek (BZ) jet is quenched and a new transient hot reconnecting plasmoid is launched by the reconnecting field. The ratio of the γ-rays to X-rays changes from {L}γ /{L}{{X}}\\gt 1 in the BZ jet to {L}γ /{L}{{X}}\\lt 1 during the launching of the transient plasmoid.

  16. Hyperaccreting Black Hole as Gamma-Ray Burst Central Engine. I. Baryon Loading in Gamma-Ray Burst Jets

    NASA Astrophysics Data System (ADS)

    Lei, Wei-Hua; Zhang, Bing; Liang, En-Wei

    2013-03-01

    A hyperaccreting stellar-mass black hole has been long speculated as the best candidate for the central engine of gamma-ray bursts (GRBs). Recent rich observations of GRBs by space missions such as Swift and Fermi pose new constraints on GRB central engine models. In this paper, we study the baryon-loading processes of a GRB jet launched from a black hole central engine. We consider a relativistic jet powered by \

  17. Active galaxies. A strong magnetic field in the jet base of a supermassive black hole.

    PubMed

    Martí-Vidal, Ivan; Muller, Sébastien; Vlemmings, Wouter; Horellou, Cathy; Aalto, Susanne

    2015-04-17

    Active galactic nuclei (AGN) host some of the most energetic phenomena in the universe. AGN are thought to be powered by accretion of matter onto a rotating disk that surrounds a supermassive black hole. Jet streams can be boosted in energy near the event horizon of the black hole and then flow outward along the rotation axis of the disk. The mechanism that forms such a jet and guides it over scales from a few light-days up to millions of light-years remains uncertain, but magnetic fields are thought to play a critical role. Using the Atacama Large Millimeter/submillimeter Array (ALMA), we have detected a polarization signal (Faraday rotation) related to the strong magnetic field at the jet base of a distant AGN, PKS 1830-211. The amount of Faraday rotation (rotation measure) is proportional to the integral of the magnetic field strength along the line of sight times the density of electrons. The high rotation measures derived suggest magnetic fields of at least tens of Gauss (and possibly considerably higher) on scales of the order of light-days (0.01 parsec) from the black hole.

  18. REGULATION OF BLACK HOLE WINDS AND JETS ACROSS THE MASS SCALE

    SciTech Connect

    King, A. L.; Miller, J. M.; Gueltekin, K.; Raymond, J.; Fabian, A. C.; Cackett, E. M.; Reynolds, C. S.; Allen, S. W.; Proga, D.; Kallman, T. R.

    2013-01-10

    We present a study of the mechanical power generated by both winds and jets across the black hole mass scale. We begin with the study of ionized X-ray winds and present a uniform analysis using Chandra grating spectra. The high-quality grating spectra facilitate the characterization of the outflow velocity, ionization, and column density of the absorbing gas. We find that the kinetic power of the winds, derived from these observed quantities, scales with increasing bolometric luminosity as log (L {sub wind,42}/C{sub v} ) = (1.58 {+-} 0.07)log (L {sub Bol,42}) - (3.19 {+-} 0.19). This suggests that supermassive black holes may be more efficient than stellar-mass black holes in launching winds, per unit filling factor, C{sub v} . If the black hole binary (BHB) and active galactic nucleus (AGN) samples are fit individually, the slopes flatten to {alpha}{sup BHB} = 0.91 {+-} 0.31 and {alpha}{sup AGN} = 0.63 {+-} 0.30 (formally consistent within errors). The broad fit and individual fits both characterize the data fairly well, and the possibility of common slopes may point to common driving mechanisms across the mass scale. For comparison, we examine jet production, estimating jet power based on the energy required to inflate local bubbles. The jet relation is log (L {sub Jet,42}) = (1.18 {+-} 0.24)log (L {sub Bondi,42}) - (0.96 {+-} 0.43). The energetics of the bubble associated with Cygnus X-1 are particularly difficult to determine, and the bubble could be a background supernova remnant. If we exclude Cygnus X-1 from our fits, then the jets follow a relation consistent with the winds, but with a higher intercept, log (L {sub Jet,42}) = (1.34 {+-} 0.50)log (L {sub Bondi,42}) - (0.80 {+-} 0.82). The formal consistency in the wind and jet scaling relations, when assuming that L {sub Bol} and L {sub Bondi} are both proxies for mass accretion rate, suggests that a common launching mechanism may drive both flows; magnetic processes, such as magnetohydrodynamics and

  19. Relativistic jet activity from the tidal disruption of a star by a massive black hole.

    PubMed

    Burrows, D N; Kennea, J A; Ghisellini, G; Mangano, V; Zhang, B; Page, K L; Eracleous, M; Romano, P; Sakamoto, T; Falcone, A D; Osborne, J P; Campana, S; Beardmore, A P; Breeveld, A A; Chester, M M; Corbet, R; Covino, S; Cummings, J R; D'Avanzo, P; D'Elia, V; Esposito, P; Evans, P A; Fugazza, D; Gelbord, J M; Hiroi, K; Holland, S T; Huang, K Y; Im, M; Israel, G; Jeon, Y; Jeon, Y-B; Jun, H D; Kawai, N; Kim, J H; Krimm, H A; Marshall, F E; P Mészáros; Negoro, H; Omodei, N; Park, W-K; Perkins, J S; Sugizaki, M; Sung, H-I; Tagliaferri, G; Troja, E; Ueda, Y; Urata, Y; Usui, R; Antonelli, L A; Barthelmy, S D; Cusumano, G; Giommi, P; Melandri, A; Perri, M; Racusin, J L; Sbarufatti, B; Siegel, M H; Gehrels, N

    2011-08-24

    Supermassive black holes have powerful gravitational fields with strong gradients that can destroy stars that get too close, producing a bright flare in ultraviolet and X-ray spectral regions from stellar debris that forms an accretion disk around the black hole. The aftermath of this process may have been seen several times over the past two decades in the form of sparsely sampled, slowly fading emission from distant galaxies, but the onset of the stellar disruption event has not hitherto been observed. Here we report observations of a bright X-ray flare from the extragalactic transient Swift J164449.3+573451. This source increased in brightness in the X-ray band by a factor of at least 10,000 since 1990 and by a factor of at least 100 since early 2010. We conclude that we have captured the onset of relativistic jet activity from a supermassive black hole. A companion paper comes to similar conclusions on the basis of radio observations. This event is probably due to the tidal disruption of a star falling into a supermassive black hole, but the detailed behaviour differs from current theoretical models of such events.

  20. Indication of the Black Hole Powered Jet in M87 by VSOP Observations

    NASA Astrophysics Data System (ADS)

    Asada, Keiichi; Nakamura, Masanori; Pu, Hung-Yi

    2016-12-01

    In order to study the collimation and acceleration mechanism of relativistic jets, the jet streamline of M87 at milliarcsecond scale is extensively investigated with images from VSOP observations at 1.6 and 5 GHz. Thanks to the higher angular resolution of VSOP, especially in the direction transverse to the jet, we resolved the jet streamline into three ridgelines at the scale of milli arcseconds. While the properties of the outer two ridgelines are in good agreement with those measured in previous observations and can be expressed by one power-law line with a power law index of 1.7, an inner ridgeline is clearly observed for the first time. We compared the measured size with the outermost streamline expected by Blandford & Znajek's parabolic solutions, which are anchored at the event horizon, with different black hole spin parameters. We revealed that the observed inner ridgeline is narrower than the prediction, suggesting the origin of the inner ridgeline to be part of a spine originating from the spinning black hole. The inner ridgeline becomes very dim at large distances from the central engine at 5 GHz. We considered two possible cases for this; Doppler beaming and/or radiative cooling. Either case seems to be reasonable for its explanation, and future multi-frequency observations will discriminate those two possibilities.

  1. Connections Between Jet Formation and Multiwavelength Spectral Evolution in Black Hole Transients

    NASA Technical Reports Server (NTRS)

    Kakemci, Emrah; Chun, Yoon-Young; Dincer, Tolga; Buxton, Michelle; Tomsick, John A.; Corbel, Stephane; Kaaret, Philip

    2011-01-01

    Multiwavelength observations are the key to understand conditions of jet formation in Galactic black hole transient (GBHT) systems. By studying radio and optical-infrared evolution of such systems during outburst decays, the compact jet formation can be traced. Comparing this with X-ray spectral and timing evolution we can obtain physical and geometrical conditions for jet formation, and study the contribution of jets to X-ray emission. In this work, first X-ray evolution - jet relation for XTE J1752-223 will be discussed. This source had very good coverage in X-rays, optical, infrared and radio. A long exposure with INTEGRAL also allowed us to study gamma-ray behavior after the jet turns on. We will also show results from the analysis of data from GX 339-4 in the hard state with SUZAKU at low flux levels. The fits to iron line fluorescence emission show that the inner disk radius increases by a factor of greater than 27 with respect to radii in bright states. This result, along with other disk radius measurements in the hard state will be discussed within the context of conditions for launching and sustaining jets.

  2. Connections between jet formation and multiwavelength spectral evolution in black hole transients

    NASA Astrophysics Data System (ADS)

    Kalemci, Emrah; Chun, Yoon-Young; Dinçer, Tolga; Buxton, Michelle; Tomsick, John A.; Corbel, Stephane; Kaaret, Philip

    2011-02-01

    Multiwavelength observations are the key to understand conditions of jet formation in Galactic black hole transient (GBHT) systems. By studying radio and optical-infrared evolution of such systems during outburst decays, the compact jet formation can be traced. Comparing this with X-ray spectral and timing evolution we can obtain physical and geometrical conditions for jet formation, and study the contribution of jets to X-ray emission. In this work, first X-ray evolution - jet relation for XTE J1752-223 will be discussed. This source had very good coverage in X-rays, optical, infrared and radio. A long exposure with INTEGRAL also allowed us to study gamma-ray behavior after the jet turns on. We will also show results from the analysis of data from GX 339-4 in the hard state with SUZAKU at low flux levels. The fits to iron line fluorescence emission show that the inner disk radius increases by a factor of >27 with respect to radii in bright states. This result, along with other disk radius measurements in the hard state will be discussed within the context of conditions for launching and sustaining jets.

  3. A highly magnetized twin-jet base pinpoints a supermassive black hole

    NASA Astrophysics Data System (ADS)

    Baczko, A.-K.; Schulz, R.; Kadler, M.; Ros, E.; Perucho, M.; Krichbaum, T. P.; Böck, M.; Bremer, M.; Grossberger, C.; Lindqvist, M.; Lobanov, A. P.; Mannheim, K.; Martí-Vidal, I.; Müller, C.; Wilms, J.; Zensus, J. A.

    2016-09-01

    Supermassive black holes (SMBH) are essential for the production of jets in radio-loud active galactic nuclei (AGN). Theoretical models based on (Blandford & Znajek 1977, MNRAS, 179, 433) extract the rotational energy from a Kerr black hole, which could be the case for NGC 1052, to launch these jets. This requires magnetic fields on the order of 103G to 104G. We imaged the vicinity of the SMBH of the AGN NGC 1052 with the Global Millimetre VLBI Array and found a bright and compact central feature that is smaller than 1.9 light days (100 Schwarzschild radii) in radius. Interpreting this as a blend of the unresolved jet bases, we derive the magnetic field at 1 Schwarzschild radius to lie between 200 G and ~ 8.3 × 104 G consistent with Blandford & Znajek models. The VLBI images shown in Figs. 3 and 4 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/593/A47

  4. Constraints on supermassive black hole spins from observations of active galaxy jets

    NASA Astrophysics Data System (ADS)

    Kun, E.; Wiita, P. J.; Gergely, L. Á.; Keresztes, Z.; Gopal-Krishna; Biermann, P. L.

    2013-11-01

    We discuss the origin of the low-energy cutoff, or LEC, seen in the radio spectra of many extragalactic jets and relate this to the spin of the supermassive black holes that presumably power them. Pion decay via proton-proton collisions is a possible mechanism to supply a secondary positron population with a low energy limit. We expect that pion production would occur in advection dominated accretion flows or ADAFs. In radiatively inefficient ADAFs the heat energy of the accreting gas is unable to radiate in less than the accretion time and the particle temperature could be high enough so that thermal protons can yield such pion production. Strong starbursts are another option for the injection of a truncated particle population into the jet. The role of both mechanisms is discussed with respect to the black hole spin estimate. The energy demanded to produce the pion decay process involves a minimum threshold for kinetic energy of the interacting protons. Therefore the mean proton speed in the flow can determine whether a LEC is generated. In ADAFs the random velocity of the protons can exceed the minimum speed limit of pion production around the jet launching region in the innermost part of the flow. Finally we summarize the additional work needed to put the model assumptions on a more rigorous basis.

  5. Radio crickets: chirping jets from black hole binaries entering their gravitational wave inspiral

    NASA Astrophysics Data System (ADS)

    Kulkarni, Girish; Loeb, Abraham

    2016-03-01

    We study a novel electromagnetic signature of supermassive black hole (BH) binaries whose inspiral starts being dominated by gravitational wave (GW) emission. Recent simulations suggest that the binary's member BHs can continue to accrete gas from the circumbinary accretion disc in this phase of the binary's evolution, all the way until coalescence. If one of the binary members produces a radio jet as a result of accretion, the jet precesses along a biconical surface due to the binary's orbital motion. When the binary enters the GW phase of its evolution, the opening angle widens, the jet exhibits milliarcsecond-scale wiggles, and the conical surface of jet precession is twisted due to apparent superluminal motion. The rapidly increasing orbital velocity of the binary gives the jet an appearance of a `chirp'. This helical chirping morphology of the jet can be used to infer the binary parameters. For binaries with mass 107-1010 M⊙ at redshifts z < 0.5, monitoring these features in current and archival data will place a lower limit on sources that could be detected by Evolved Laser Interferometer Space Antenna and Pulsar Timing Arrays. In the future, microarcsecond interferometry with the Square Kilometre Array will increase the potential usefulness of this technique.

  6. Baryons in the relativistic jets of the stellar-mass black-hole candidate 4U 1630-47.

    PubMed

    Trigo, María Díaz; Miller-Jones, James C A; Migliari, Simone; Broderick, Jess W; Tzioumis, Tasso

    2013-12-12

    Accreting black holes are known to power relativistic jets, both in stellar-mass binary systems and at the centres of galaxies. The power carried away by the jets, and, hence, the feedback they provide to their surroundings, depends strongly on their composition. Jets containing a baryonic component should carry significantly more energy than electron-positron jets. Energetic considerations and circular-polarization measurements have provided conflicting circumstantial evidence for the presence or absence of baryons in jets, and the only system in which they have been unequivocally detected is the peculiar X-ray binary SS 433 (refs 4, 5). Here we report the detection of Doppler-shifted X-ray emission lines from a more typical black-hole candidate X-ray binary, 4U 1630-47, coincident with the reappearance of radio emission from the jets of the source. We argue that these lines arise from baryonic matter in a jet travelling at approximately two-thirds the speed of light, thereby establishing the presence of baryons in the jet. Such baryonic jets are more likely to be powered by the accretion disk than by the spin of the black hole, and if the baryons can be accelerated to relativistic speeds, the jets should be strong sources of γ-rays and neutrino emission.

  7. Observing Black Hole Spin

    NASA Astrophysics Data System (ADS)

    Reynolds, Christopher S.

    2015-08-01

    Black hole spin is important in both the fundamental physics and astrophysics realms. In fundamental terms, many extensions and alternatives to General Relativity (GR) reveal themselves through effects related to (or at least of the same order as) spin. Astrophysically, spin is a fossil record of how black holes have grown and may, in addition, be an important source of energy (e.g., powering relativistic jets from black hole systems). I shall review recent progress on observational studies of black hole spin, especially those made in the X-ray waveband. We now have multiple techniques that can be applied in our search for black hole spin; I shall discuss the concordance (or, sometimes, lack thereof) between these techniques. Finally, I shall discuss what we can expect in the next few years with the launch of new X-ray instrumentation as well as the deployment of the Event Horizon Telescope.

  8. LAUNCHING AND QUENCHING OF BLACK HOLE RELATIVISTIC JETS AT LOW ACCRETION RATE

    SciTech Connect

    Pu, Hung-Yi; Chang, Hsiang-Kuang; Hirotani, Kouichi

    2012-10-20

    Relativistic jets are launched from black hole (BH) X-ray binaries and active galactic nuclei when the disk accretion rate is below a certain limit (i.e., when the ratio of the accretion rate to the Eddingtion accretion rate, m-dot , is below about 0.01) but quenched when above. We propose a new paradigm to explain this observed coupling between the jet and the accretion disk by investigating the extraction of the rotational energy of a BH when it is surrounded by different types of accretion disk. At low accretion rates (e.g., when m-dot {approx}<0.1), the accretion near the event horizon is quasi-spherical. The accreting plasmas fall onto the event horizon in a wide range of latitudes, breaking down the force-free approximation near the horizon. To incorporate the plasma inertia effect, we consider the magnetohydrodynamical (MHD) extraction of the rotational energy from BHs by the accreting MHD fluid, as described by the MHD Penrose process. It is found that the energy extraction operates, and hence a relativistic jet is launched, preferentially when the accretion disk consists of an outer Shakura-Sunyaev disk (SSD) and an inner advection-dominated accretion flow. When the entire accretion disk type changes into an SSD, the jet is quenched because the plasmas bring more rest-mass energy than what is extracted from the hole electromagnetically to stop the extraction. Several other issues related to observed BH disk-jet couplings, such as why the radio luminosity increases with increasing X-ray luminosity until the radio emission drops, are also explained.

  9. Black Hole Simulation

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This graphic shows the computer simulation of a black hole from start to finish. Plasma is falling slowly toward the black hole in a (at the upper left). The plasma has a magnetic field, shown by the white lines. It picks up speed as it falls toward the hole in b (at the upper right), c (lower left) and d (lower right). However, the rotating black hole twists up space itself (and the magnetic field lines) and ejects electromagnetic power along the north and south poles above the black hole. The red and white color shows the immense electromagnetic power output, which eventually will pick up particles and form squirting jets. This simulation was conducted using supercomputers at Japan's National Institute for Fusion Science.

  10. Evidence for Ultra-Energetic Particles in Jet from Black Hole

    NASA Astrophysics Data System (ADS)

    2006-06-01

    New Haven, Conn. -- An international team of astronomers led by researchers at Yale has obtained key infrared observations that reveal the nature of quasar particle jets that originate just outside super-massive black holes at the center of galaxies and radiate across the spectrum from radio to X-ray wavelengths; a complementary study of jet X-ray emission led by astronomers at the University of Southampton, reaches the same conclusion. Composite of 3C273's jet Chandra, Hubble, and Spitzer composite of 3C273 Credit: NASA/JPL-Caltech/Yale Univ. Press Image and Caption Both studies involve the jet of the quasar 3C273, famous since its identification in 1963 as the first quasar. It now appears that the most energetic radiation from this jet arises through direct radiation from extremely energetic particles, and not in the way expected by most astronomers based on the previously available data. The two reports, available now online in the Astrophysical Journal, will appear in print in the September 10 issue. "Quasar jets, although extremely luminous, are so distant as to be relatively faint and difficult to observe. Thanks to the sensitivity of NASA's Great Observatories, we have been able to map the 3C273 jet in infrared, visible light and X-rays," said C. Megan Urry, Israel Munson Professor of Physics and Astronomy at Yale, and an author on one study. "These combined data strongly suggest that ultra-energetic particles in the 3C273 jet are producing their light via synchrotron radiation." Composite showing the relation between the quasar 3C273 and the jet Composite showing the relation between the quasar 3C273 (top left; the quasar is a very small and bright source, the fuzz apparently surrounding it is an artifact that appears when taking a picture of a very bright source with a camera and telescope for very faint things) and the jet. The color coding is the same as in the image above. Credit: NASA/NRAO, S.Jester, D.E.Harris, H.L.Marshall, K.Meisenheimer, H

  11. Structural Transition in the NGC 6251 Jet: an Interplay with the Supermassive Black Hole and Its Host Galaxy

    NASA Astrophysics Data System (ADS)

    Tseng, Chih-Yin; Asada, Keiichi; Nakamura, Masanori; Pu, Hung-Yi; Algaba, Juan-Carlos; Lo, Wen-Ping

    2016-12-01

    The structure of the NGC 6251 jet on the milliarcsecond scale is investigated using images taken with the European VLBI Network and the Very Long Baseline Array. We detect a structural transition of the jet from a parabolic to a conical shape at a distance of (1-2) × 105 times the Schwarzschild radius from the central engine, which is close to the sphere of gravitational influence of the supermassive black hole (SMBH). We also examine the jet pressure profiles with the synchrotron minimum energy assumption to discuss the physical origin of the structural transition. The NGC 6251 jet, together with the M87 jet, suggests a fundamental process of structural transition in the jets of active galactic nuclei (AGNs). Collimated AGN jets are characterized by their external galactic medium, showing that AGN jets interplay with the SMBH and its host galaxy.

  12. An origin of the radio jet in M87 at the location of the central black hole.

    PubMed

    Hada, Kazuhiro; Doi, Akihiro; Kino, Motoki; Nagai, Hiroshi; Hagiwara, Yoshiaki; Kawaguchi, Noriyuki

    2011-09-07

    Powerful radio jets from active galactic nuclei are thought to be powered by the accretion of material onto the supermassive black hole (the 'central engine'). M87 is one of the closest examples of this phenomenon, and the structure of its jet has been probed on a scale of about 100 Schwarzschild radii (R(s), the radius of the event horizon). However, the location of the central black hole relative to the jet base (a bright compact radio 'core') remains elusive. Observations of other jets indicate that the central engines are located about 10(4)-10(6)R(s) upstream from the radio core. Here we report radio observations of M87 at six frequencies that allow us to achieve a positional accuracy of about 20 microarcseconds. As the jet base becomes more transparent at higher frequencies, the multifrequency position measurements of the radio core enable us to determine the upstream end of the jet. The data reveal that the central engine of M87 is located within 14-23R(s) of the radio core at 43 GHz. This implies that the site of material infall onto the black hole and the eventual origin of the jet reside in the bright compact region seen on the image at 43 GHz.

  13. Tidal disruption and magnetic flux capture: powering a jet from a quiescent black hole

    NASA Astrophysics Data System (ADS)

    Kelley, Luke Zoltan; Tchekhovskoy, Alexander; Narayan, Ramesh

    2014-12-01

    The transient Swift J1644+57 is believed to have been produced by an unlucky star wandering too close to a supermassive black hole (BH) leading to a tidal disruption event. This unusual flare displayed highly super-Eddington X-ray emission which likely originated in a relativistic, collimated jet. This presents challenges to modern accretion and jet theory as upper limits of prior BH activity, which we obtain from the radio afterglow of this event, imply that both the pre-disruption BH and stellar magnetic fluxes fall many orders of magnitude short of what is required to power the observed X-ray luminosity. We argue that a pre-existing, `fossil' accretion disc can contain a sufficient reservoir of magnetic flux and that the stellar debris stream is capable of dragging this flux into the BH. To demonstrate this, we perform local, 3D magnetohydrodynamic simulations of the disc-stream interaction and demonstrate that the interface between the two is unstable to mixing. This mixing entrains a sufficient amount of fossil disc magnetic flux into the infalling stellar debris to power the jet. We argue that the interaction with the fossil disc can have a pronounced effect on the structure and dynamics of mass fallback and likely the resulting transient. Finally, we describe possible ramifications of these interactions on unresolved problems in tidal disruption dynamics, in particular, the efficiency of debris circularization, and effects of the disruption on the pre-existing BH system.

  14. HYPERACCRETING BLACK HOLE AS GAMMA-RAY BURST CENTRAL ENGINE. I. BARYON LOADING IN GAMMA-RAY BURST JETS

    SciTech Connect

    Lei Weihua; Zhang Bing; Liang Enwei E-mail: zhang@physics.unlv.edu

    2013-03-10

    A hyperaccreting stellar-mass black hole has been long speculated as the best candidate for the central engine of gamma-ray bursts (GRBs). Recent rich observations of GRBs by space missions such as Swift and Fermi pose new constraints on GRB central engine models. In this paper, we study the baryon-loading processes of a GRB jet launched from a black hole central engine. We consider a relativistic jet powered by {nu} {nu}-bar -annihilation or by the Blandford-Znajek (BZ) mechanism. We consider baryon loading from a neutrino-driven wind launched from a neutrino-cooling-dominated accretion flow. For a magnetically dominated BZ jet, we consider neutron drifting from the magnetic wall surrounding the jet and subsequent positron capture and proton-neutron inelastic collisions. The minimum baryon loads in both types of jet are calculated. We find that in both cases a more luminous jet tends to be more baryon poor. A neutrino-driven ''fireball'' is typically ''dirtier'' than a magnetically dominated jet, while a magnetically dominated jet can be much cleaner. Both models have the right scaling to interpret the empirical {Gamma}-L{sub iso} relation discovered recently. Since some neutrino-driven jets have too much baryon loading as compared with the data, we suggest that at least a good fraction of GRBs should have a magnetically dominated central engine.

  15. A possible relativistic jetted outburst from a massive black hole fed by a tidally disrupted star.

    PubMed

    Bloom, Joshua S; Giannios, Dimitrios; Metzger, Brian D; Cenko, S Bradley; Perley, Daniel A; Butler, Nathaniel R; Tanvir, Nial R; Levan, Andrew J; O'Brien, Paul T; Strubbe, Linda E; De Colle, Fabio; Ramirez-Ruiz, Enrico; Lee, William H; Nayakshin, Sergei; Quataert, Eliot; King, Andrew R; Cucchiara, Antonino; Guillochon, James; Bower, Geoffrey C; Fruchter, Andrew S; Morgan, Adam N; van der Horst, Alexander J

    2011-07-08

    Gas accretion onto some massive black holes (MBHs) at the centers of galaxies actively powers luminous emission, but most MBHs are considered dormant. Occasionally, a star passing too near an MBH is torn apart by gravitational forces, leading to a bright tidal disruption flare (TDF). Although the high-energy transient Sw 1644+57 initially displayed none of the theoretically anticipated (nor previously observed) TDF characteristics, we show that observations suggest a sudden accretion event onto a central MBH of mass about 10(6) to 10(7) solar masses. There is evidence for a mildly relativistic outflow, jet collimation, and a spectrum characterized by synchrotron and inverse Compton processes; this leads to a natural analogy of Sw 1644+57 to a temporary smaller-scale blazar.

  16. Complete multiwavelength evolution of Galactic black hole transients during outburst decay. I. Conditions for 'compact' jet formation

    SciTech Connect

    Kalemci, E.; Dinçer, T.; Chun, Y. Y.; Tomsick, J. A.; Buxton, M. M.; Bailyn, C. D.

    2013-12-20

    Compact, steady jets are observed in the near infrared and radio bands in the hard state of Galactic black hole transients as their luminosity decreases and the source moves toward a quiescent state. Recent radio observations indicate that the jets turn off completely in the soft state; therefore, multiwavelength monitoring of black hole transients is essential to probe the formation of jets. In this work, we conducted a systematic study of all black hole transients with near infrared and radio coverage during their outburst decays. We characterized the timescales of changes in X-ray spectral and temporal properties and also in near infrared and/or in radio emission. We confirmed that state transitions occur in black hole transients at a very similar fraction of their respective Eddington luminosities. We also found that the near infrared flux increase that could be due to the formation of a compact jet is delayed by a time period of days with respect to the formation of a corona. Finally, we found a threshold disk Eddington luminosity fraction for the compact jets to form. We explain these results with a model such that the increase in the near infrared flux corresponds to a transition from a patchy, small-scale height corona along with an optically thin outflow to a large-scale height corona that allows for collimation of a steady compact jet. We discuss the timescale of jet formation in terms of transport of magnetic fields from the outer parts of the disk, and we also consider two alternative explanations for the multiwavelength emission: hot inner accretion flows and irradiation.

  17. Using radiative energy losses to constrain the magnetization and magnetic reconnection rate at the base of black hole jets

    NASA Astrophysics Data System (ADS)

    Potter, William J.

    2017-02-01

    We calculate the severe radiative energy losses which occur at the base of black hole jets using a relativistic fluid jet model, including in situ acceleration of non-thermal leptons by magnetic reconnection. Our results demonstrate that including a self-consistent treatment of radiative energy losses is necessary to perform accurate magnetohydrodynamic simulations of powerful jets and that jet spectra calculated via post-processing are liable to vastly overestimate the amount of non-thermal emission. If no more than 95 per cent of the initial total jet power is radiated away by the plasma travels as it travels along the length of the jet, we can place a lower bound on the magnetization of the jet plasma at the base of the jet. For typical powerful jets, we find that the plasma at the jet base is required to be highly magnetized, with at least 10 000 times more energy contained in magnetic fields than in non-thermal leptons. Using a simple power-law model of magnetic reconnection, motivated by simulations of collisionless reconnection, we determine the allowed range of the large-scale average reconnection rate along the jet, by restricting the total radiative energy losses incurred and the distance at which the jet first comes into equipartition. We calculate analytic expressions for the cumulative radiative energy losses due to synchrotron and inverse-Compton emission along jets, and derive analytic formulae for the constraint on the initial magnetization.

  18. The evolving corona and evidence for jet launching from the supermassive black hole in Markarian 335

    NASA Astrophysics Data System (ADS)

    Wilkins, Daniel; Gallo, Luigi C.

    2015-01-01

    Through detailed analysis of the X-rays that are reflected from the accretion disc, it is possible to probe structures right down to the innermost stable circular orbit and event horizon around the supermassive black holes in AGN. By measuring the illumination pattern of the accretion disc, along with reverberation time lags between variability in the X-ray continuum and reflection, unprecedented detail of the geometry and spatial extent of the corona that produces the X-ray continuum has emerged when the observed data are combined with insight gained from general relativistic ray tracing simulations.We conducted detailed analysis of both the X-ray continuum and its reflection from the accretion disc in the narrow line Seyfert 1 galaxy Markarian 335, over observations spanning nearly a decade to measure the underlying changes in the structure of the X-ray emitting corona that gave rise to more than an order of magnitude variation in luminosity.Underlying this long timescale variability lies much more complex patterns of behaviour on short timescales. We are, for the first time, able to observe and measure the changes in the structure of the corona that give rise to transient phenomena including a flare in the X-ray emission seen during a low flux state by Suzaku in July 2013. This flaring event was found to mark a reconfiguration of the corona while there is evidence that the flare itself was cased by an aborted jet-launching event. More recently, detailed analysis of a NuSTAR target of opportunity observation is letting us understand the sudden increase in X-ray flux by a factor of 15 in Markarian 335 seen in September 2014.These observations allow us to trace, from observations, the evolution of the X-ray emitting corona that gives rise to not only the extreme variability seen in the X-ray emission from AGN, but also the processes by which jets and other outflow are launched from the extreme environments around black holes. This gives us important insight into

  19. Powerful radiative jets in supercritical accretion discs around non-spinning black holes

    NASA Astrophysics Data System (ADS)

    Sądowski, Aleksander; Narayan, Ramesh

    2015-11-01

    We describe a set of simulations of supercritical accretion on to a non-rotating supermassive black hole (BH). The accretion flow takes the form of a geometrically thick disc with twin low-density funnels around the rotation axis. For accretion rates {gtrsim } 10 dot{M}_Edd, there is sufficient gas in the funnel to make this region optically thick. Radiation from the disc first flows into the funnel, after which it accelerates the optically thick funnel gas along the axis. The resulting jet is baryon loaded and has a terminal density-weighted velocity ≈0.3c. Much of the radiative luminosity is converted into kinetic energy by the time the escaping gas becomes optically thin. These jets are not powered by BHrotation or magnetic driving, but purely by radiation. Their characteristic beaming angle is ˜0.2 rad. For an observer viewing down the axis, the isotropic equivalent luminosity of total energy is as much as 1048 erg s- 1 for a 107 M⊙ BH accreting at 103 Eddington. Therefore, energetically, the simulated jets are consistent with observations of the most powerful tidal disruption events, e.g. Swift J1644. The jet velocity is, however, too low to match the Lorentz factor γ > 2 inferred in J1644. There is no such conflict in the case of other tidal disruption events. Since favourably oriented observers see isotropic equivalent luminosities that are highly super-Eddington, the simulated models can explain observations of ultraluminous X-ray sources, at least in terms of luminosity and energetics, without requiring intermediate-mass BHs.

  20. Disk-jet coupling in the Galactic black hole X-ray binary MAXI J1836-194

    NASA Astrophysics Data System (ADS)

    Russell, Thomas

    2014-01-01

    There is a universal connection between the accretion and ejection phenomena that are observed in black holes across the mass scale. Quantifying this relationship is the first step in understanding how jets are launched, accelerated and collimated. X-ray binaries are ideal systems to study this relationship, as they evolve on human timescales. In outburst, their luminosities increase by several orders of magnitude, with the thermal X-ray emission from the accretion disk and the radio emission from the relativistic jets undergoing dramatic, coupled changes. We present the results of our multiwavelength radio through to X-ray observations of the Galactic black hole candidate X-ray binary MAXI J1836-194 during its 2011 outburst. We find that this system has a near face-on accretion disk with the jet, that is pointed almost directly towards us, accounting for ~6% of the total energy output of the system early in the outburst. We observed the frequency of the transition from optically thick to optically thin synchrotron emission in the jet spectrum evolve by ~3 orders of magnitude as the jet gradually switches on and off on a timescale of a few weeks. This evolution does not appear to follow the expected positive relation with source luminosity. Instead the jet break shifted to higher frequencies as the source luminosity decreased and is likely coupled to the accretion flow in a more complex way. We find the region where the jet is accelerated up to relativistic speeds occurs at much larger distances from the black hole than previously thought and does not scale with the inner radius of the accretion disk. Our simultaneous, high cadence observations provide an unprecedented insight into the accretion processes occurring during an outburst, allowing us to observe the compact jet evolve and the corresponding changes within the accretion regime. This has implications for the launching of jets on all scales, from X-ray binaries to their larger-scale analogues, AGN.

  1. Imaging the supermassive black hole shadow and jet base of M87 with the event horizon telescope

    SciTech Connect

    Lu, Ru-Sen; Fish, Vincent L.; Doeleman, Sheperd S.; Pankratius, Victor; Broderick, Avery E.; Baron, Fabien; Monnier, John D.

    2014-06-20

    The Event Horizon Telescope (EHT) is a project to assemble a Very Long Baseline Interferometry (VLBI) network of millimeter wavelength dishes that can resolve strong field general relativistic signatures near a supermassive black hole. As planned, the EHT will include enough dishes to enable imaging of the predicted black hole 'shadow', a feature caused by severe light bending at the black hole boundary. The center of M87, a giant elliptical galaxy, presents one of the most interesting EHT targets as it exhibits a relativistic jet, offering the additional possibility of studying jet genesis on Schwarzschild radius scales. Fully relativistic models of the M87 jet that fit all existing observational constraints now allow horizon-scale images to be generated. We perform realistic VLBI simulations of M87 model images to examine the detectability of the black shadow with the EHT, focusing on a sequence of model images with a changing jet mass load radius. When the jet is launched close to the black hole, the shadow is clearly visible both at 230 and 345 GHz. The EHT array with a resolution of 20-30 μas resolution (∼2-4 Schwarzschild radii) is able to image this feature independent of any theoretical models and we show that imaging methods used to process data from optical interferometers are applicable and effective for EHT data sets. We demonstrate that the EHT is also capable of tracing real-time structural changes on a few Schwarzschild radii scales, such as those implicated by very high-energy flaring activity of M87. While inclusion of ALMA in the EHT is critical for shadow imaging, the array is generally robust against loss of a station.

  2. Imaging the Supermassive Black Hole Shadow and Jet Base of M87 with the Event Horizon Telescope

    NASA Astrophysics Data System (ADS)

    Lu, Ru-Sen; Broderick, Avery E.; Baron, Fabien; Monnier, John D.; Fish, Vincent L.; Doeleman, Sheperd S.; Pankratius, Victor

    2014-06-01

    The Event Horizon Telescope (EHT) is a project to assemble a Very Long Baseline Interferometry (VLBI) network of millimeter wavelength dishes that can resolve strong field general relativistic signatures near a supermassive black hole. As planned, the EHT will include enough dishes to enable imaging of the predicted black hole "shadow," a feature caused by severe light bending at the black hole boundary. The center of M87, a giant elliptical galaxy, presents one of the most interesting EHT targets as it exhibits a relativistic jet, offering the additional possibility of studying jet genesis on Schwarzschild radius scales. Fully relativistic models of the M87 jet that fit all existing observational constraints now allow horizon-scale images to be generated. We perform realistic VLBI simulations of M87 model images to examine the detectability of the black shadow with the EHT, focusing on a sequence of model images with a changing jet mass load radius. When the jet is launched close to the black hole, the shadow is clearly visible both at 230 and 345 GHz. The EHT array with a resolution of 20-30 μas resolution (~2-4 Schwarzschild radii) is able to image this feature independent of any theoretical models and we show that imaging methods used to process data from optical interferometers are applicable and effective for EHT data sets. We demonstrate that the EHT is also capable of tracing real-time structural changes on a few Schwarzschild radii scales, such as those implicated by very high-energy flaring activity of M87. While inclusion of ALMA in the EHT is critical for shadow imaging, the array is generally robust against loss of a station.

  3. Launching proton-dominated jets from accreting Kerr black holes: the case of M87

    NASA Astrophysics Data System (ADS)

    Brezinski, F.; Hujeirat, A. A.

    2011-07-01

    A general relativistic model for the formation and acceleration of lowmass-loaded jets from systems containing accreting black holes is presented. The model is based on previous numerical results and theoretical studies in the Newtonian regime, but modified to include the effects of space-time curvature in the vicinity of the event horizon of a spinning black hole. It is argued that the boundary layer between the Keplerian accretion disk and the event horizon is best suited for the formation and acceleration of the accretion-powered jets in active galactic nuclei and micro-quasars. The model presented here is based on matching the solutions of three different regions: i- a weakly magnetized Keplerian accretion disk in the outer part, where the transport of angular momentum is mediated through the magentorotational instability, ii- a strongly magnetized, advection-dominated and turbulent-free boundary layer (BL) between the outer cold accretion disk and the event horizon and where the plasma rotates sub-Keplerian and iiia transition zone (TZ) between the BL and the overlying corona, where the electrons and protons are thermally uncoupled, highly dissipative and rotate super-Keplerian. In the BL, the gravitation-driven dynamical collapse of the plasma increases the strength of the poloidal magnetic field (PMF) significantly, subsequently suppressing the generation and dissipation of turbulence and turning off the primary source of heating. In this case, the BL appears much fainter than standard disk models so as if the disk truncates at a certain radius. The action of the PMF in the BL is to initiate torsional Alf`ven waves that transport angular momentum from the embedded plasma vertically into the TZ, where a significant fraction of the shear-generated toroidal magnetic field reconnects, thereby heating the protons up to the virial-temperature. Also, the strong PMF forces the electrons to cool rapidly, giving rise therefore to the formation of a gravitationally

  4. Disc-jet Coupling in the 2009 Outburst of the Black Hole Candidate H1743-322

    NASA Technical Reports Server (NTRS)

    Miller-Jones, J. C. A.; Sivakoff, G. R.; Altamirano, D.; Coriat, M.; Corbel, S.; Dhawan, V.; Krimm, H. A.; Remillard, R. A.; Rupen, M. P.; Russell, D. M.; Fender, R. P.; Heinz, S.; Kording, E. G.; Maitra, D.; Markoff, S.; Migliari, S.; Sarazin, C. L.; Tudose, V.

    2012-01-01

    We present an intensive radio and X-ray monitoring campaign on the 2009 outburst of the Galactic black hole candidate X-ray binary H1743-322. With the high angular resolution of the Very Long Baseline Array, we resolve the jet ejection event and measure the proper motions of the jet ejecta relative to the position of the compact core jets detected at the beginning of the outburst. This allows us to accurately couple the moment when the jet ejection event occurred with X-ray spectral and timing signatures. We find that X-ray timing signatures are the best diagnostic of the jet ejection event in this outburst, which occurred as the X-ray variability began to decrease and the Type C quasi-periodic oscillations disappeared from the X-ray power density spectrum. However, this sequence of events does not appear to be replicated in all black hole X-ray binary outbursts, even within an individual source. In our observations of H1743-322, the ejection was contemporaneous with a quenching of the radio emission, prior to the start of the major radio flare. This contradicts previous assumptions that the onset of the radio flare marks the moment of ejection. The jet speed appears to vary between outbursts with a positive correlation outburst luminosity. The compact core radio jet reactivated on transition to the hard intermediate state at the end of the outburst and not when the source reached the low hard spectral state. Comparison with the known near-infrared behaviour of the compact jets suggests a gradual evolution of the compact jet power over a few days near beginning the and end of an outburst

  5. THE DYNAMICS, APPEARANCE, AND DEMOGRAPHICS OF RELATIVISTIC JETS TRIGGERED BY TIDAL DISRUPTION OF STARS IN QUIESCENT SUPERMASSIVE BLACK HOLES

    SciTech Connect

    De Colle, Fabio; Guillochon, James; Naiman, Jill; Ramirez-Ruiz, Enrico E-mail: jfg@ucolick.org E-mail: enrico@ucolick.org

    2012-12-01

    We examine the consequences of a model in which relativistic jets can be triggered in quiescent massive black holes when a geometrically thick and hot accretion disk forms as a result of the tidal disruption of a star. To estimate the power, thrust, and lifetime of the jet, we use the mass accretion history onto the black hole as calculated by detailed hydrodynamic simulations of the tidal disruption of stars. We go on to determine the states of the interstellar medium in various types of quiescent galactic nuclei, and describe how this external matter can affect jets propagating through it. We use this information, together with a two-dimensional hydrodynamic model of the structure of the relativistic flow, to study the dynamics of the jet, the propagation of which is regulated by the density stratification of the environment and by its injection history. The breaking of symmetry involved in transitioning from one to two dimensions is crucial and leads to qualitatively new phenomena. At early times, as the jet power increases, the high pressure of the cocoon collimates the jet, increasing its shock velocity as compared to that of spherical models. We show that small velocity gradients, induced near or at the source, steepen into internal shocks and provide a source of free energy for particle acceleration and radiation along the jet's channel. The jets terminate at a working surface where they interact strongly with the surrounding medium through a combination of shock waves and instabilities; a continuous flow of relativistic fluid emanating from the nucleus supplies this region with mass, momentum, and energy. Information about the t {sup -5/3} decrease in power supply propagates within the jet at the internal sound speed. As a result, the internal energy at the jet head continues to accumulate until long after the peak feeding rate is reached. An appreciable time delay is thus expected between peaks in the short-wavelength radiation emanating near the jet

  6. A jet emission model to probe the dynamics of accretion and ejection coupling in black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Malzac, Julien

    2016-07-01

    Compact jets are probably the most common form of jets in X-ray binaries and Active Galactic Nuclei. They seem to be present in all sources in the so-called hard X-ray spectral state. They are characterised by a nearly flat Spectral Energy Distribution (SED) extending from the radio to the infrared bands. This emission is usually interpreted as partially self absorbed synchrotron emission from relativistic leptons accelerated in the jet. The observed flat spectral shape requires energy dissipation and acceleration of particules over a wide range of distances along the jet. This distributed energy dissipation is likely to be powered by internal shocks caused by fluctuations of the outflow velocity. I will discuss such an internal shock model in the context of black hole binaries. I will show that internal shocks can produce the observed SEDs and also predict a strong, wavelength dependent, variability that resembles the observed one. The assumed velocity fluctuations of the jet must originate in the accretion flow. The model thus predicts a strong connection between the observable properties of the jet in the radio to IR bands, and the variability of the accretion flow as observed in X-rays. If the model is correct, this offers a unique possibility to probe the dynamics of the coupled accretion and ejection processes leading to the formation of compact jets.

  7. Erratic Black Hole Regulates Itself

    NASA Astrophysics Data System (ADS)

    2009-03-01

    New results from NASA's Chandra X-ray Observatory have made a major advance in explaining how a special class of black holes may shut off the high-speed jets they produce. These results suggest that these black holes have a mechanism for regulating the rate at which they grow. Black holes come in many sizes: the supermassive ones, including those in quasars, which weigh in at millions to billions of times the mass of the Sun, and the much smaller stellar-mass black holes which have measured masses in the range of about 7 to 25 times the Sun's mass. Some stellar-mass black holes launch powerful jets of particles and radiation, like seen in quasars, and are called "micro-quasars". The new study looks at a famous micro-quasar in our own Galaxy, and regions close to its event horizon, or point of no return. This system, GRS 1915+105 (GRS 1915 for short), contains a black hole about 14 times the mass of the Sun that is feeding off material from a nearby companion star. As the material swirls toward the black hole, an accretion disk forms. This system shows remarkably unpredictable and complicated variability ranging from timescales of seconds to months, including 14 different patterns of variation. These variations are caused by a poorly understood connection between the disk and the radio jet seen in GRS 1915. Chandra, with its spectrograph, has observed GRS 1915 eleven times since its launch in 1999. These studies reveal that the jet in GRS 1915 may be periodically choked off when a hot wind, seen in X-rays, is driven off the accretion disk around the black hole. The wind is believed to shut down the jet by depriving it of matter that would have otherwise fueled it. Conversely, once the wind dies down, the jet can re-emerge. "We think the jet and wind around this black hole are in a sort of tug of war," said Joseph Neilsen, Harvard graduate student and lead author of the paper appearing in the journal Nature. "Sometimes one is winning and then, for reasons we don

  8. A Dancing Black Hole

    NASA Astrophysics Data System (ADS)

    Shoemaker, Deirdre; Smith, Kenneth; Schnetter, Erik; Fiske, David; Laguna, Pablo; Pullin, Jorge

    2002-04-01

    Recently, stationary black holes have been successfully simulated for up to times of approximately 600-1000M, where M is the mass of the black hole. Considering that the expected burst of gravitational radiation from a binary black hole merger would last approximately 200-500M, black hole codes are approaching the point where simulations of mergers may be feasible. We will present two types of simulations of single black holes obtained with a code based on the Baumgarte-Shapiro-Shibata-Nakamura formulation of the Einstein evolution equations. One type of simulations addresses the stability properties of stationary black hole evolutions. The second type of simulations demonstrates the ability of our code to move a black hole through the computational domain. This is accomplished by shifting the stationary black hole solution to a coordinate system in which the location of the black hole is time dependent.

  9. NASA Now: Black Holes

    NASA Video Gallery

    In this NASA Now episode, Dr. Daniel Patnaude talks about how his team discovered a baby black hole, why this is important and how black holes create tidal forces. Throughout his discussion, Patnau...

  10. Black hole hair removal

    NASA Astrophysics Data System (ADS)

    Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke

    2009-07-01

    Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair — degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

  11. Irradiation of an Accretion Disc by a Jet: General Properties and Implications for Spin Measurements of Black Holes

    NASA Technical Reports Server (NTRS)

    T.Dauser; Garcia, J.; Wilms, J.; Boeck, M.; Brenneman, L. W.; Falanga, M.; Fukumura, Keigo; Reynolds, C. S.

    2013-01-01

    X-ray irradiation of the accretion disc leads to strong reflection features, which are then broadened and distorted by relativistic effects. We present a detailed, general relativistic approach to model this irradiation for different geometries of the primary X-ray source. These geometries include the standard point source on the rotational axis as well as more jet-like sources, which are radially elongated and accelerating. Incorporating this code in the RELLINE model for relativistic line emission, the line shape for any configuration can be predicted. We study how different irradiation geometries affect the determination of the spin of the black hole. Broad emission lines are produced only for compact irradiating sources situated close to the black hole. This is the only case where the black hole spin can be unambiguously determined. In all other cases the line shape is narrower, which could either be explained by a low spin or an elongated source. We conclude that for those cases and independent of the quality of the data, no unique solution for the spin exists and therefore only a lower limit of the spin value can be given

  12. Black Hole Thermodynamics

    NASA Astrophysics Data System (ADS)

    Israel, Werner

    This chapter reviews the conceptual developments on black hole thermodynamics and the attempts to determine the origin of black hole entropy in terms of their horizon area. The brick wall model and an operational approach are discussed. An attempt to understand at the microlevel how the quantum black hole acquires its thermal properties is included. The chapter concludes with some remarks on the extension of these techniques to describing the dynamical process of black hole evaporation.

  13. Warping of an accretion disc and launching of a jet by a spinning black hole in NGC 4258

    NASA Astrophysics Data System (ADS)

    Wu, Qingwen; Yan, Hao; Yi, Zhu

    2013-12-01

    We fit the most up-to-date broad-band spectral energy distribution from radio to X-rays for NGC 4258 with a coupled accretion-jet model that surrounds a Kerr black hole (BH). Here, both the jet and the warped H2O maser disc are assumed to be triggered by a spinning BH through the Blandford-Znajek mechanism and the Bardeen-Petterson effect, respectively. The accretion flow consists of an inner radiatively inefficient accretion flow and an outer truncated standard thin disc, where the transition radius Rtr ≃ 3 × 103Rg for NGC 4258, based on the width and variability of its narrow Fe Kα line. The hybrid jet formation model, as a variant of the Blandford-Znajek model, is used to model the jet power. Therefore, we can estimate the accretion rate and BH spin through the two observed quantities (i.e. X-ray emission and jet power), where the observed jet power is estimated from the low-frequency radio emission. Using this method, we find that the BH of NGC 4258 should be mildly spinning with dimensionless spin parameter a* ≃ 0.7 ± 0.2. The outer thin disc mainly radiates at the near-infrared waveband and the jet contributes predominantly at the radio waveband. Using the above-estimated BH spin and the inferred accretion rate at the region of the maser disc based on the physical existence of the H2O maser, we find that the warp radius is ˜8.6 × 104Rg if it is driven by the Bardeen-Petterson effect. This is very consistent with the observational result.

  14. Black Hole Battery

    NASA Astrophysics Data System (ADS)

    Levin, Janna; D'Orazio, Daniel

    2016-03-01

    Black holes are dark dead stars. Neutron stars are giant magnets. As the neutron star orbits the black hole, an electronic circuit forms that generates a blast of power just before the black hole absorbs the neutron star whole. The black hole battery conceivably would be observable at cosmological distances. Possible channels for luminosity include synchro-curvature radiation, a blazing fireball, or even an unstable, short-lived black hole pulsar. As suggested by Mingarelli, Levin, and Lazio, some fraction of the battery power could also be reprocessed into coherent radio emission to populate a subclass of fast radio bursts.

  15. Magnetic fields around black holes

    NASA Astrophysics Data System (ADS)

    Garofalo, David A. G.

    Active Galactic Nuclei are the most powerful long-lived objects in the universe. They are thought to harbor supermassive black holes that range from 1 million solar masses to 1000 times that value and possibly greater. Theory and observation are converging on a model for these objects that involves the conversion of gravitational potential energy of accreting gas to radiation as well as Poynting flux produced by the interaction of the rotating spacetime and the electromagnetic fields originating in the ionized accretion flow. The presence of black holes in astrophysics is taking center stage, with the output from AGN in various forms such as winds and jets influencing the formation and evolution of the host galaxy. This dissertation addresses some of the basic unanswered questions that plague our current understanding of how rotating black holes interact with their surrounding magnetized accretion disks to produce the enormous observed energy. Two magnetic configurations are examined. The first involves magnetic fields connecting the black hole with the inner accretion disk and the other involves large scale magnetic fields threading the disk and the hole. We study the effects of the former type by establishing the consequences that magnetic torques between the black hole and the inner accretion disk have on the energy dissipation profile. We attempt a plausible explanation to the observed "Deep Minimum" state in the Seyfert galaxy MCG-6- 30-15. For the latter type of magnetic geometry, we study the effects of the strength of the magnetic field threading the black hole within the context of the cherished Blandford & Znajek mechanism for black hole spin energy extraction. We begin by addressing the problem in the non-relativistic regime where we find that the black hole-threading magnetic field is stronger for greater disk thickness, larger magnetic Prandtl number, and for a larger accretion disk. We then study the problem in full relativity where we show that our

  16. Black Holes (With 16 figures)

    NASA Astrophysics Data System (ADS)

    Novikov, Igor

    Astrophysics of Black Holes Introduction The Origin of Stellar Black Holes A Nonrotating Black Hole Introduction Schwarzschild Gravitational Field Motion of Photons Along the Radial Direction Radial Motion of Nonrelativistic Particles The Puzzle of the Gravitational Radius R and T Regions Two Types of T-Regions Gravitational Collapse and White Holes Eternal Black Hole? Black Hole Celestial Mechanics Circular Motion Around a Black Hole Gravitational Capture of Particles by a Black Hole Corrections for Gravitational Radiation A Rotating Black Hole Introduction Gravitational Field of a Rotating Black Hole Specific Reference Frames General Properties of the Spacetime of a Rotating Black Hole; - Spacetime Inside the Horizon Celestial Mechanics of a Rotating Black Hole Motion of Particle in the Equatorial Plane Motion of Particles off the Equatorial Plane Peculiarities of the Gravitational Capture of Bodies by a Rotating - Black Hole Electromagnetic Fields Near a Black Hole Introduction Maxwell's Equations in the Neighborhood of a Rotating Black Hole Stationary Electrodynamics Boundary Conditions at the Event Horizon Electromagnetic Fields in Vacuum Magnetosphere of a Black Hole Some Aspects of Physics of Black Holes, Wormholes, and Time Machines Observational Appearence of the Black Holes in the Universe Black Holes in the Interstellar Medium Disk Accretion Black Holes in Stellar Binary Systems Black Holes in Galactic Centers Dynamical Evidence for Black Holes in Galaxy Nuclei Primordial Black Holes Acknowledgements References

  17. Powerful jets from black hole X-ray binaries in low/hard X-ray states

    NASA Astrophysics Data System (ADS)

    Fender, R. P.

    2001-03-01

    Four persistent (Cygnus X-1, GX 339-4, GRS 1758-258 and 1E 1740.7-2942) and three transient (GS 2023+38, GRO J0422+32 and GS 1354-64) black hole X-ray binary systems have been extensively observed at radio wavelengths during extended periods in the low/hard X-ray state, which is characterized in X-rays by a hard power-law spectrum and strong variability. All seven systems show a persistent flat or inverted (in the sense that α>~0, where Sν~να) radio spectrum in this state, markedly different from the optically thin radio spectra exhibited by most X-ray transients within days of outburst. Furthermore, in none of the systems is a high-frequency cut-off to this spectral component detected, and there is evidence that it extends to near-infrared or optical regimes. Luminous persistent hard X-ray states in the black hole system GRS 1915+105 produce a comparable spectrum. This spectral component is considered to arise in synchrotron emission from a conical, partially self-absorbed jet, of the same genre as those originally considered for active galactic nuclei. Whatever the physical origin of the low/hard X-ray states, these self-similar outflows are an ever-present feature. The power in the jet component is likely to be a significant (>=5per cent) and approximately fixed fraction of the total accretion luminosity. The correlation between hard X-ray and synchrotron emission in all the sources implies that the jets are intimately related to the Comptonization process, and do not have very large bulk Lorentz factors, unless the hard X-ray emission is also beamed by the same factor.

  18. RELATIONSHIP BETWEEN THE KINETIC POWER AND BOLOMETRIC LUMINOSITY OF JETS: LIMITATION FROM BLACK HOLE X-RAY BINARIES, ACTIVE GALACTIC NUCLEI, AND GAMMA-RAY BURSTS

    SciTech Connect

    Ma, Renyi; Hou, Shujin; Xie, Fu-Guo E-mail: fgxie@shao.ac.cn

    2014-01-01

    The correlation between the kinetic power P {sub jet} and intrinsic bolometric luminosity L {sub jet} of jets may reveal the underlying jet physics in various black hole systems. Based on the recent work by Nemmen et al., we re-investigate this correlation with additional sources of black hole X-ray binaries (BXBs) in hard/quiescent states and low-luminosity active galactic nuclei (LLAGNs). The new sample includes 29 sets of data from 7 BXBs and 20 LLAGNs, with P {sub jet} and L {sub jet} being derived from spectral modeling of the quasi-simultaneous multi-band spectra under the accretion jet scenario. Compared to previous works, the range of luminosity is now enlarged to more than 20 decades, i.e., from ∼10{sup 31} erg s{sup –1} to ∼10{sup 52} erg s{sup –1}, which allows for better constraining of the correlation. One notable result is that the jets in BXBs and LLAGNs almost follow the same P {sub jet}-L {sub jet} correlation that was obtained from blazars and gamma-ray bursts. The slope indices we derived are 1.03 ± 0.01 for the whole sample, 0.85 ± 0.06 for the BXB subsample, 0.71 ± 0.11 for the LLAGN subsample, and 1.01 ± 0.05 for the LLAGN-blazar subsample, respectively. The correlation index around unit implies the independence of jet efficiency on the luminosity or kinetic power. Our results may further support the hypothesis that similar physical processes exist in the jets of various black hole systems.

  19. An Evolving Compact Jet in the Black Hole X-Ray Binary Maxi J1836-194

    NASA Technical Reports Server (NTRS)

    Russell, D. M.; Russell, T. D.; Miller-Jones, J. C. A.; O'Brien, K.; Soria, R.; Sivakoff, G. R.; Slaven-Blair, T.; Lewis, F.; Markoff, S.; Homan, J.; Altanirano, D.; Curran, P. A.; Rupen, M. P.; Belloni, T. M.; Cadolle Bel, M.; Casella, P.; Corbel, S.; Dhawan, V.; Fender, R. P.; Gallo, E.; Gandhi, P.; Heinz, S.; Koerding, E. G.; Krimm, H. A.; Maitra, D.

    2013-01-01

    We report striking changes in the broadband spectrum of the compact jet of the black hole transient MAXI J1836-194 over state transitions during its discovery outburst in 2011. A fading of the optical-infrared (IR) flux occurred as the source entered the hard-intermediate state, followed by a brightening as it returned to the hard state. The optical-IR spectrum was consistent with a power law from optically thin synchrotron emission, except when the X-ray spectrum was softest. By fitting the radio to optical spectra with a broken power law, we constrain the frequency and flux of the optically thick/thin break in the jet synchrotron spectrum. The break gradually shifted to higher frequencies as the source hardened at X-ray energies, from approx 10(exp 11) to approx 4 × 10(exp 13) Hz. The radiative jet luminosity integrated over the spectrum appeared to be greatest when the source entered the hard state during the outburst decay (although this is dependent on the high-energy cooling break, which is not seen directly), even though the radio flux was fading at the time. The physical process responsible for suppressing and reactivating the jet (neither of which are instantaneous but occur on timescales of weeks) is uncertain, but could arise from the varying inner accretion disk radius regulating the fraction of accreting matter that is channeled into the jet. This provides an unprecedented insight into the connection between inflow and outflow, and has implications for the conditions required for jets to be produced, and hence their launching process.

  20. An Evolving Compact Jet in the Black Hole X-Ray Binary MAXI J1836-194

    NASA Astrophysics Data System (ADS)

    Russell, D. M.; Russell, T. D.; Miller-Jones, J. C. A.; O'Brien, K.; Soria, R.; Sivakoff, G. R.; Slaven-Blair, T.; Lewis, F.; Markoff, S.; Homan, J.; Altamirano, D.; Curran, P. A.; Rupen, M. P.; Belloni, T. M.; Cadolle Bel, M.; Casella, P.; Corbel, S.; Dhawan, V.; Fender, R. P.; Gallo, E.; Gandhi, P.; Heinz, S.; Körding, E. G.; Krimm, H. A.; Maitra, D.; Migliari, S.; Remillard, R. A.; Sarazin, C. L.; Shahbaz, T.; Tudose, V.

    2013-05-01

    We report striking changes in the broadband spectrum of the compact jet of the black hole transient MAXI J1836-194 over state transitions during its discovery outburst in 2011. A fading of the optical-infrared (IR) flux occurred as the source entered the hard-intermediate state, followed by a brightening as it returned to the hard state. The optical-IR spectrum was consistent with a power law from optically thin synchrotron emission, except when the X-ray spectrum was softest. By fitting the radio to optical spectra with a broken power law, we constrain the frequency and flux of the optically thick/thin break in the jet synchrotron spectrum. The break gradually shifted to higher frequencies as the source hardened at X-ray energies, from ~1011 to ~4 × 1013 Hz. The radiative jet luminosity integrated over the spectrum appeared to be greatest when the source entered the hard state during the outburst decay (although this is dependent on the high-energy cooling break, which is not seen directly), even though the radio flux was fading at the time. The physical process responsible for suppressing and reactivating the jet (neither of which are instantaneous but occur on timescales of weeks) is uncertain, but could arise from the varying inner accretion disk radius regulating the fraction of accreting matter that is channeled into the jet. This provides an unprecedented insight into the connection between inflow and outflow, and has implications for the conditions required for jets to be produced, and hence their launching process. Based on observations collected at the European Southern Observatory, Chile, under ESO Program IDs 087.D-0914 and 089.D-0970.

  1. AN EVOLVING COMPACT JET IN THE BLACK HOLE X-RAY BINARY MAXI J1836-194

    SciTech Connect

    Russell, D. M.; Russell, T. D.; Miller-Jones, J. C. A.; Soria, R.; Slaven-Blair, T.; Curran, P. A.; O'Brien, K.; Sivakoff, G. R.; Lewis, F.; Markoff, S.; Altamirano, D.; Homan, J.; Rupen, M. P.; Dhawan, V.; Belloni, T. M.; Cadolle Bel, M.; Casella, P.; Corbel, S.; Gallo, E.; and others

    2013-05-10

    We report striking changes in the broadband spectrum of the compact jet of the black hole transient MAXI J1836-194 over state transitions during its discovery outburst in 2011. A fading of the optical-infrared (IR) flux occurred as the source entered the hard-intermediate state, followed by a brightening as it returned to the hard state. The optical-IR spectrum was consistent with a power law from optically thin synchrotron emission, except when the X-ray spectrum was softest. By fitting the radio to optical spectra with a broken power law, we constrain the frequency and flux of the optically thick/thin break in the jet synchrotron spectrum. The break gradually shifted to higher frequencies as the source hardened at X-ray energies, from {approx}10{sup 11} to {approx}4 Multiplication-Sign 10{sup 13} Hz. The radiative jet luminosity integrated over the spectrum appeared to be greatest when the source entered the hard state during the outburst decay (although this is dependent on the high-energy cooling break, which is not seen directly), even though the radio flux was fading at the time. The physical process responsible for suppressing and reactivating the jet (neither of which are instantaneous but occur on timescales of weeks) is uncertain, but could arise from the varying inner accretion disk radius regulating the fraction of accreting matter that is channeled into the jet. This provides an unprecedented insight into the connection between inflow and outflow, and has implications for the conditions required for jets to be produced, and hence their launching process.

  2. Black Hole Blows Big Bubble

    NASA Astrophysics Data System (ADS)

    2010-07-01

    Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help

  3. Uniformly accelerated black holes

    NASA Astrophysics Data System (ADS)

    Letelier, Patricio S.; Oliveira, Samuel R.

    2001-09-01

    The static and stationary C metric are examined in a generic framework and their interpretations studied in some detail, especially those with two event horizons, one for the black hole and another for the acceleration. We find that (i) the spacetime of an accelerated static black hole is plagued by either conical singularities or a lack of smoothness and compactness of the black hole horizon, (ii) by using standard black hole thermodynamics we show that accelerated black holes have a higher Hawking temperature than Unruh temperature of the accelerated frame, and (iii) the usual upper bound on the product of the mass and acceleration parameters (<1/27) is just a coordinate artifact. The main results are extended to accelerated rotating black holes with no significant changes.

  4. Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Loeb, Abraham

    2007-04-01

    Recent data indicates that almost all galaxies possess a supermassive black hole at their center. When gas accretes onto the black hole it heats-up and shines, resulting in the appearance of a bright quasar. The earliest quasars are found to exist only a billion years after the big-bang. I will describe recent observations of both the nearest and the most distant supermassive black holes in the universe. The formation and evolution of the black hole population can be described in the context of popular models for galaxy formation. I will describe the key questions that drive current research on supermassive black holes and present theoretical work on the radiative and hydrodynamic effects that quasars have on their cosmic habitat. Within the coming decade it would be possible to test general relativity by monitoring over time, and possibly even imaging, the polarized emission from hot spots around the black hole in the center of our Galaxy (SgrA*).

  5. Jet-dominated quiescent states in black hole X-ray binaries: the case of V404 Cyg

    NASA Astrophysics Data System (ADS)

    Xie, Fu-Guo; Yang, Qi-Xiang; Ma, Renyi

    2014-07-01

    The dynamical structure and radiative properties of the quiescent state (X-ray luminosity ≲1034 erg s-1) of black hole X-ray transients (BHXTs) remain unclear, mainly because of low luminosity and poor data quantity. We demonstrate that the simultaneous multi-wavelength (including radio, optical, ultraviolet and X-ray bands) spectrum of V404 Cyg in its bright quiescent state can be well described by the radiation from the companion star and more importantly, the compact jet. Neither the outer thin disc nor the inner hot accretion flow is important in the total spectrum. Together with recent findings, i.e. the power-law X-ray spectrum and the non-variable X-ray spectral shape (or constant photon index) in contrast to the dramatic change in the X-ray luminosity, we argue the quiescent state spectrum of BHXTs is actually jet-dominated. Additional observational properties consistent with this jet model are also discussed as supporting evidence.

  6. Black Hole Blows Big Bubble

    NASA Astrophysics Data System (ADS)

    2010-07-01

    Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help

  7. The Nearest Black Holes

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald J. (Technical Monitor); Garcia, M.

    2003-01-01

    The goal of this program is to study black holes, both in our Galaxy and in nearby galaxies. We aim to study both 'stellar mass' x-ray binaries containing black holes (both in our Galaxy and in nearby galaxies), and super-massive black holes in nearby galaxies. This program facilitates this study by funding related travel, computer equipment, and partial salary for a post-doc.

  8. The Nearest Black Holes

    NASA Technical Reports Server (NTRS)

    Garcia, M.; Oliversen, Ronald J. (Technical Monitor)

    2004-01-01

    The goal of this program is to study black holes, both in our Galaxy and in nearby galaxies. We aim to study both 'stellar mass' x-ray binaries containing black holes (both in our Galaxy and in nearby galaxies), and super-massive black holes in nearby galaxies. This program facilitate this study by funding related travel, computer equipment, and partial salary for a post-doc.

  9. Asymptotic black holes

    NASA Astrophysics Data System (ADS)

    Ho, Pei-Ming

    2017-04-01

    Following earlier works on the KMY model of black-hole formation and evaporation, we construct the metric for a matter sphere in gravitational collapse, with the back-reaction of pre-Hawking radiation taken into consideration. The mass distribution and collapsing velocity of the matter sphere are allowed to have an arbitrary radial dependence. We find that a generic gravitational collapse asymptote to a universal configuration which resembles a black hole but without horizon. This approach clarifies several misunderstandings about black-hole formation and evaporation, and provides a new model for black-hole-like objects in the universe.

  10. Evidence for black holes.

    PubMed

    Begelman, Mitchell C

    2003-06-20

    Black holes are common objects in the universe. Each galaxy contains large numbers-perhaps millions-of stellar-mass black holes, each the remnant of a massive star. In addition, nearly every galaxy contains a supermassive black hole at its center, with a mass ranging from millions to billions of solar masses. This review discusses the demographics of black holes, the ways in which they interact with their environment, factors that may regulate their formation and growth, and progress toward determining whether these objects really warp spacetime as predicted by the general theory of relativity.

  11. NASA's Chandra Finds Black Holes Are "Green"

    NASA Astrophysics Data System (ADS)

    2006-04-01

    Black holes are the most fuel efficient engines in the Universe, according to a new study using NASA's Chandra X-ray Observatory. By making the first direct estimate of how efficient or "green" black holes are, this work gives insight into how black holes generate energy and affect their environment. The new Chandra finding shows that most of the energy released by matter falling toward a supermassive black hole is in the form of high-energy jets traveling at near the speed of light away from the black hole. This is an important step in understanding how such jets can be launched from magnetized disks of gas near the event horizon of a black hole. Illustration of Fuel for a Black Hole Engine Illustration of Fuel for a Black Hole Engine "Just as with cars, it's critical to know the fuel efficiency of black holes," said lead author Steve Allen of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University, and the Stanford Linear Accelerator Center. "Without this information, we cannot figure out what is going on under the hood, so to speak, or what the engine can do." Allen and his team used Chandra to study nine supermassive black holes at the centers of elliptical galaxies. These black holes are relatively old and generate much less radiation than quasars, rapidly growing supermassive black holes seen in the early Universe. The surprise came when the Chandra results showed that these "quiet" black holes are all producing much more energy in jets of high-energy particles than in visible light or X-rays. These jets create huge bubbles, or cavities, in the hot gas in the galaxies. Animation of Black Hole in Elliptical Galaxy Animation of Black Hole in Elliptical Galaxy The efficiency of the black hole energy-production was calculated in two steps: first Chandra images of the inner regions of the galaxies were used to estimate how much fuel is available for the black hole; then Chandra images were used to estimate the power required to produce

  12. Black Holes Shed Light on Galaxy Formation

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This videotape is comprised of several segments of animations on black holes and galaxy formation, and several segments of an interview with Dr. John Kormendy. The animation segments are: (1) a super massive black hole, (2) Centarus A active black hole found in a collision, (3) galaxy NGC-4261 (active black hole and jet model), (4) galaxy M-32 (orbits of stars are effected by the gravity of the black hole), (5) galaxy M-37 (motion of stars increases as mass of black hole increases), (6) Birth of active galactic nuclei, (7) the collision of two galaxy leads to merger of the black holes, (8) Centarus A and simulation of the collision of 2 galaxies. There are also several segments of an interview with John Kormendy. In these segments he discusses the two most important aspects of his recent black hole work: (1) the correlations between galaxies speed and the mass of the black holes, and (2) the existence of black holes and galactic formation. He also discusses the importance of the Hubble Space Telescope and the Space Telescope Imaging Spectrograph to the study of black holes. He also shows the methodology of processing images from the spectrograph in his office.

  13. MODELING THE JET KINEMATICS OF THE BLACK HOLE MICROQUASAR XTE J1550-564: A CONSTRAINT ON SPIN-ORBIT ALIGNMENT

    SciTech Connect

    Steiner, James F.; McClintock, Jeffrey E.

    2012-02-01

    Measurements of black hole spin made using the continuum-fitting method rely on the assumption that the inclination of the black hole's spin axis to our line of sight is the same as the orbital inclination angle i of the host binary system. The X-ray and radio jet data available for the microquasar XTE J1550-564 offer a rare opportunity to test this assumption. Following the work of others, we have modeled these data and thereby determined the inclination angle {theta} of the jet axis, which is presumed to be aligned with the black hole's spin axis. We find {theta} Almost-Equal-To 71 Degree-Sign and place an upper limit on the difference between the spin and orbital inclinations of |{theta} - i| < 12 Degree-Sign (90% confidence). Our measurement tests for misalignment along the line of sight while providing no constraint perpendicular to this plane. Our constraint on the misalignment angle supports the prediction that the spinning black hole in XTE J1550-564 has aligned itself with the orbital plane and provides support for the measurement of its spin via the continuum-fitting method. Our conclusions are based on a simple and reasonable model of a pair of symmetric jets propagating into a low-density cavity whose western wall is Almost-Equal-To 20% closer to XTE J1550-564 than its eastern wall.

  14. A late jet rebrightening revealed from multiwavelength monitoring of the black hole candidate XTE J1752-223

    NASA Astrophysics Data System (ADS)

    Russell, D. M.; Curran, P. A.; Muñoz-Darias, T.; Lewis, F.; Motta, S.; Stiele, H.; Belloni, T.; Miller-Jones, J. C. A.; Jonker, P. G.; O'Brien, K.; Homan, J.; Casella, P.; Gandhi, P.; Soleri, P.; Markoff, S.; Maitra, D.; Gallo, E.; Cadolle Bel, M.

    2012-01-01

    We present optical monitoring of the black hole candidate XTE J1752-223 during its 2009-10 outburst and decay to quiescence. The optical light curve can be described by an exponential decay followed by a plateau, then a more rapid fade towards quiescence. The plateau appears to be due to an extra component of optical emission that brightens and then fades over ˜40 days. We show evidence for the origin of this optical 'flare' to be the synchrotron jet during the decaying hard state, and we identify and isolate both disc and jet components in the spectral energy distributions. The optical flare has the same morphology and amplitude as a contemporaneous X-ray rebrightening. This suggests a common origin, but no firm conclusions can be made favouring or disfavouring the jet producing the X-ray flare. The quiescent optical magnitudes are B≥ 20.6, V≥ 21.1, R≥ 19.5, i'≥ 19.2. From the optical outburst amplitude we estimate a likely orbital period of <22 h. We also present near-infrared (NIR) photometry and polarimetry and rare mid-IR imaging (8-12 ?m) when the source is nearing quiescence. The fading jet component, and possibly the companion star, may contribute to the NIR flux. We derive deep mid-IR flux upper limits and NIR linear polarization upper limits. With the inclusion of radio data, we measure an almost flat jet spectral index between radio and optical; Fν∝ν˜+0.05. The data favour the jet break to optically thin emission to reside in the IR, but may shift to frequencies as high as the optical or UV during the peak of the flare. Based on observations collected at the European Southern Observatory, Chile, under ESO Programme ID 086.D-0610, the William Herschel Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias and the Faulkes Telescopes at Haleakala, Maui, USA and Siding Spring, Australia.

  15. Dumb holes: analogues for black holes.

    PubMed

    Unruh, W G

    2008-08-28

    The use of sonic analogues to black and white holes, called dumb or deaf holes, to understand the particle production by black holes is reviewed. The results suggest that the black hole particle production is a low-frequency and low-wavenumber process.

  16. Early black hole signals at the LHC

    SciTech Connect

    Koch, Ben; Bleicher, Marcus; Stoecker, Horst

    2007-10-26

    The production of mini black holes due to large extra dimensions is a speculative but possible scenario. We survey estimates for di-jet suppression, and multi-mono-jet emission due to black hole production. We further look for a possible sub-scenario which is the formation of a stable or meta-stable black hole remnant (BHR). We show that the beauty of such objects is, that they are relatively easy to observe, even in the early phase of LHC running.

  17. Early black hole signals at the LHC

    NASA Astrophysics Data System (ADS)

    Koch, Ben; Bleicher, Marcus; Stöcker, Horst

    2007-10-01

    The production of mini black holes due to large extra dimensions is a speculative but possible scenario. We survey estimates for di-jet suppression, and multi-mono-jet emission due to black hole production. We further look for a possible sub-scenario which is the formation of a stable or meta-stable black hole remnant (BHR). We show that the beauty of such objects is, that they are relatively easy to observe, even in the early phase of LHC running.

  18. ULTRAMASSIVE BLACK HOLE COALESCENCE

    SciTech Connect

    Khan, Fazeel Mahmood; Holley-Bockelmann, Kelly; Berczik, Peter E-mail: k.holley@vanderbilt.edu

    2015-01-10

    Although supermassive black holes (SMBHs) correlate well with their host galaxies, there is an emerging view that outliers exist. Henize 2-10, NGC 4889, and NGC 1277 are examples of SMBHs at least an order of magnitude more massive than their host galaxy suggests. The dynamical effects of such ultramassive central black holes is unclear. Here, we perform direct N-body simulations of mergers of galactic nuclei where one black hole is ultramassive to study the evolution of the remnant and the black hole dynamics in this extreme regime. We find that the merger remnant is axisymmetric near the center, while near the large SMBH influence radius, the galaxy is triaxial. The SMBH separation shrinks rapidly due to dynamical friction, and quickly forms a binary black hole; if we scale our model to the most massive estimate for the NGC 1277 black hole, for example, the timescale for the SMBH separation to shrink from nearly a kiloparsec to less than a parsec is roughly 10 Myr. By the time the SMBHs form a hard binary, gravitational wave emission dominates, and the black holes coalesce in a mere few Myr. Curiously, these extremely massive binaries appear to nearly bypass the three-body scattering evolutionary phase. Our study suggests that in this extreme case, SMBH coalescence is governed by dynamical friction followed nearly directly by gravitational wave emission, resulting in a rapid and efficient SMBH coalescence timescale. We discuss the implications for gravitational wave event rates and hypervelocity star production.

  19. Black holes and beyond

    SciTech Connect

    Mathur, Samir D.

    2012-11-15

    The black hole information paradox forces us into a strange situation: we must find a way to break the semiclassical approximation in a domain where no quantum gravity effects would normally be expected. Traditional quantizations of gravity do not exhibit any such breakdown, and this forces us into a difficult corner: either we must give up quantum mechanics or we must accept the existence of troublesome 'remnants'. In string theory, however, the fundamental quanta are extended objects, and it turns out that the bound states of such objects acquire a size that grows with the number of quanta in the bound state. The interior of the black hole gets completely altered to a 'fuzzball' structure, and information is able to escape in radiation from the hole. The semiclassical approximation can break at macroscopic scales due to the large entropy of the hole: the measure in the path integral competes with the classical action, instead of giving a subleading correction. Putting this picture of black hole microstates together with ideas about entangled states leads to a natural set of conjectures on many long-standing questions in gravity: the significance of Rindler and de Sitter entropies, the notion of black hole complementarity, and the fate of an observer falling into a black hole. - Highlights: Black-Right-Pointing-Pointer The information paradox is a serious problem. Black-Right-Pointing-Pointer To solve it we need to find 'hair' on black holes. Black-Right-Pointing-Pointer In string theory we find 'hair' by the fuzzball construction. Black-Right-Pointing-Pointer Fuzzballs help to resolve many other issues in gravity.

  20. Measuring Black Hole Spin

    NASA Astrophysics Data System (ADS)

    Garmire, Gordon

    1999-09-01

    WE PROPOSE TO CARRY OUT A SYSTEMATIC STUDY OF EMISSION AND ABSORPTION SPECTRAL FEATURES THAT ARE OFTEN SEEN IN X-RAY SPECTRA OF BLACK HOLE BINARIES. THE EXCELLENT SENSITIVITY AND ENERGY RESOLUTION OF THE ACIS/HETG COMBINATION WILL NOT ONLY HELP RESOLVE AMBIGUITIES IN INTERPRETING THESE FEATURES, BUT MAY ALLOW MODELLING OF THE EMISSION LINE PROFILES IN DETAIL. THE PROFILES MAY CONTAIN INFORMATION ON SUCH FUNDAMENTAL PROPERTIES AS THE SPIN OF BLACK HOLES. THEREFORE, THIS STUDY COULD LEAD TO A MEASUREMENT OF BLACK HOLE SPIN FOR SELECTED SOURCES. THE RESULT CAN THEN BE DIRECTLY COMPARED WITH THOSE FROM PREVIOUS STUDIES BASED ON INDEPENDENT METHODS.

  1. Unifying Black Hole Jets: The Connection between Blazars and Gamma-ray Bursts

    NASA Astrophysics Data System (ADS)

    Nemmen, Rodrigo

    2012-07-01

    Radio-loud AGNs and gamma-ray bursts produce powerful relativistic jets and their central engines share the same basic astrophysical ingredients, despite the vastly different mass scales. An outstanding question is how the jet physics scales from GRBs up to AGNs. Using Fermi and Swift observations as well as data obtained with several other observatories, we show that the jets produced by blazars and long-duration GRBs exhibit similar correlations between the kinetic power and apparent gamma-ray luminosity, with AGNs and GRBs lying at the low and high-luminosity end, respectively, of the trend. After carrying out the beaming correction for these two populations, we find evidence that blazars and GRBs follow the same correlation between the intrinsic gamma-ray luminosity and kinetic power. This result implies that jet production and energy dissipation mechanisms are remarkably similar across over 9 orders of magnitude in jet power, establishing a physical analogy between AGN and GRBs. Our results indicate that these jets convert their internal energy into radiation with efficiencies exceeding 10%. We will discuss the implications of these results in terms of the properties of the central engines of AGNs and GRBs, in particular the bulk Lorentz factor, jet opening angles and mass accretion rates.

  2. Unifying Black Hole Jets: The Connection between radio-loud AGNs and Gamma-ray Bursts

    NASA Astrophysics Data System (ADS)

    Nemmen, Rodrigo

    2012-07-01

    Radio-loud AGNs and gamma-ray bursts produce powerful relativistic jets and their central engines share the same basic astrophysical ingredients, despite the vastly different mass scales. An outstanding question is how the jet physics scales from GRBs up to AGNs.Using Fermi and Swift observations as well as data obtained with several other observatories, we show that the jets produced by blazars and long-duration GRBs exhibit similar correlations between the kinetic power and apparent gamma-ray luminosity, with AGNs and GRBs lying at the low and high-luminosity end, respectively, of the trend. After carrying out the beaming correction for these two populations, we find evidence that blazars and GRBs follow the same correlation between the intrinsic gamma-ray luminosity and kinetic power. This result implies that jet production and energy dissipation mechanisms are remarkably similar across over 9 orders of magnitude in jet power, establishing a physical analogy between AGN and GRBs. Our results indicate that these jets convert their internal energy into radiation with efficiencies exceeding 10%. We will discuss the implications of these results in terms of the properties of the central engines of AGNs and GRBs, in particular the bulk Lorentz factor, jet opening angles and mass accretion rates.

  3. Introducing the Black Hole

    ERIC Educational Resources Information Center

    Ruffini, Remo; Wheeler, John A.

    1971-01-01

    discusses the cosmology theory of a black hole, a region where an object loses its identity, but mass, charge, and momentum are conserved. Include are three possible formation processes, theorized properties, and three way they might eventually be detected. (DS)

  4. Illuminating black holes

    NASA Astrophysics Data System (ADS)

    Barr, Ian A.; Bull, Anne; O'Brien, Eileen; Drillsma-Milgrom, Katy A.; Milgrom, Lionel R.

    2016-07-01

    Two-dimensional shadows formed by illuminating vortices are shown to be visually analogous to the gravitational action of black holes on light and surrounding matter. They could be useful teaching aids demonstrating some of the consequences of general relativity.

  5. Tidal disruption jets of supermassive black holes as hidden sources of cosmic rays: Explaining the IceCube TeV-PeV neutrinos

    NASA Astrophysics Data System (ADS)

    Wang, Xiang-Yu; Liu, Ruo-Yu

    2016-04-01

    Cosmic ray interactions that produce high-energy neutrinos also inevitably generate high-energy gamma rays, which finally contribute to the diffuse high-energy gamma-ray background after they escape the sources. It was recently found that the high flux of neutrinos at ˜30 TeV detected by IceCube lead to a cumulative gamma-ray flux exceeding the Fermi isotropic gamma-ray background at 10-100 GeV, implying that the neutrinos are produced by hidden sources of cosmic rays, where GeV-TeV gamma rays are not transparent. Here we suggest that relativistic jets in tidal disruption events (TDEs) of supermassive black holes are such hidden sources. We consider the jet propagation in an extended, optically thick envelope around the black hole, which results from the ejected material during the disruption. While powerful jets can break free from the envelope, less powerful jets would be choked inside the envelope. The jets accelerate cosmic rays through internal shocks or reverse shocks and further produce neutrinos via interaction with the surrounding dense photons. All three TDE jets discovered so far are not detected by Fermi/LAT, suggesting that GeV-TeV gamma rays are absorbed in these jets. The cumulative neutrino flux from TDE jets can account for the neutrino flux observed by IceCube at PeV energies and may also account for the higher flux at ˜30 TeV if less powerful, choked jets are present in the majority of TDEs.

  6. Charged Galileon black holes

    SciTech Connect

    Babichev, Eugeny; Charmousis, Christos; Hassaine, Mokhtar E-mail: christos.charmousis@th.u-psud.fr

    2015-05-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematically compatible with the field equations. This opens up the possibility for novel searches of hairy black holes in a far more general setting of Horndeski theory.

  7. Searching for Black Holes

    NASA Technical Reports Server (NTRS)

    Garcia, M.

    1998-01-01

    Our UV/VIS work concentrates on black hole X-ray nova. These objects consist of two stars in close orbit, one of which we believe is a black hole - our goal is to SHOW that one is a black hole. In order to reach this goal we carry out observations in the Optical, UV, IR and X-ray bands, and compare the observations to theoretical models. In the past year, our UV/VIS grant has provided partial support (mainly travel funds and page charges) for work we have done on X-ray nova containing black holes and neutron stars. We have been very successful in obtaining telescope time to support our project - we have completed approximately a dozen separate observing runs averaging 3 days each, using the MMT (5M), Lick 3M, KPNO 2.1M, CTIO 4M, CTIO 1.5M, and the SAO/WO 1.2M telescopes. These observations have allowed the identification of one new black hole (Nova Oph 1977), and allowed the mass of another to be measured (GS2000+25). Perhaps our most exciting new result is the evidence we have gathered for the existence of 'event horizons' in black hole X-ray nova.

  8. Newborn Black Holes

    ERIC Educational Resources Information Center

    Science Teacher, 2005

    2005-01-01

    Scientists using NASA's Swift satellite say they have found newborn black holes, just seconds old, in a confused state of existence. The holes are consuming material falling into them while somehow propelling other material away at great speeds. "First comes a blast of gamma rays followed by intense pulses of x-rays. The energies involved are much…

  9. Janus black holes

    NASA Astrophysics Data System (ADS)

    Bak, Dongsu; Gutperle, Michael; Janik, Romuald A.

    2011-10-01

    In this paper Janus black holes in A dS 3 are considered. These are static solutions of an Einstein-scalar system with broken translation symmetry along the horizon. These solutions are dual to interface conformal field theories at finite temperature. An approximate solution is first constructed using perturbation theory around a planar BTZ blackhole. Numerical and exact solutions valid for all sets of parameters are then found and compared. Using the exact solution the thermodynamics of the system is analyzed. The entropy associated with the Janus black hole is calculated and it is found that the entropy of the black Janus is the sum of the undeformed black hole entropy and the entanglement entropy associated with the defect.

  10. The Evolving Polarized Jet of Black Hole Candidate Swift J1745-26

    NASA Technical Reports Server (NTRS)

    Curran, P. A.; Coriat, M.; Miller-Jones, J. C. A.; Armstrong, R. P.; Edwards, P. G.; Sivakoff, G. R.; Woudt, P.; Altamirano, D.; Belloni, T. M.; Corbel, S.; Krimm, Hans A.

    2013-01-01

    Swift J1745-26 is an X-ray binary towards the Galactic Centre that was detected when it went into outburst in September 2012. This source is thought to be one of a growing number of sources that display "failed outbursts", in which the self-absorbed radio jets of the transient source are never fully quenched and the thermal emission from the geometrically-thin inner accretion disk never fully dominates the X-ray flux. We present multifrequency data from the Very Large Array, Australia Telescope Compact Array and Karoo Array Telescope (KAT- 7) radio arrays, spanning the entire period of the outburst. Our rich data set exposes radio emission that displays a high level of large scale variability compared to the X-ray emission and deviations from the standard radio-X-ray correlation that are indicative of an unstable jet and confirm the outburst's transition from the canonical hard state to an intermediate state. We also observe steepening of the spectral index and an increase of the linear polarization to a large fraction (is approx. equal to 50%) of the total flux, as well as a rotation of the electric vector position angle. These are consistent with a transformation from a self-absorbed compact jet to optically-thin ejecta - the first time such a discrete ejection has been observed in a failed outburst - and may imply a complex magnetic field geometry.

  11. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, John

    2009-01-01

    The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. And, when the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.

  12. Merging Black Holes

    NASA Astrophysics Data System (ADS)

    Centrella, Joan

    2009-05-01

    The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. And, when the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.

  13. Disc-jet quenching of the galactic black hole Swift J1753.5-0127

    NASA Astrophysics Data System (ADS)

    Rushton, A. P.; Shaw, A. W.; Fender, R. P.; Altamirano, D.; Gandhi, P.; Uttley, P.; Charles, P. A.; Kolehmainen, M.; Anderson, G. E.; Rumsey, C.; Titterington, D. J.

    2016-11-01

    We report on radio and X-ray monitoring observations of the BHC Swift J1753.5-0127 taken over a ˜10 yr period. Presented are daily radio observations at 15 GHz with the Arcminute Microkelvin Imager Large Array (AMI-LA) and X-ray data from Swift X-ray Telescope and Burst Alert Telescope. Also presented is a deep 2 h JVLA observation taken in an unusually low-luminosity soft-state (with a low disc temperature). We show that although the source has remained relatively radio-quiet compared to XRBs with a similar X-ray luminosity in the hard-state, the power-law relationship scales as ζ = 0.96 ± 0.06, i.e. slightly closer to what has been considered for radiatively inefficient accretion discs. We also place the most stringent limit to date on the radio-jet quenching in an XRB soft-state, showing the connection of the jet quenching to the X-ray power-law component; the radio flux in the soft-state was found to be < 21 μJy, which is a quenching factor of ≳ 25.

  14. The coupling of a disk corona and a jet for the radio/X-ray correlation in black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Qiao, Erlin

    2016-02-01

    We interpret the radio/X-ray correlation of L R ~ L X ~1.4 for L X/L Edd >~ 10-3 with a detailed disk corona-jet model, in which the accretion flow and the jet are connected by a parameter, η, describing the fraction of the matter in the accretion flow ejected outward to form the jet. We calculate L R and L X at different Ṁ, adjusting η to fit the observed radio/X-ray correlation of the black hole X-ray transient H1743-322 for L X/L Edd > 10-3. It is found that the value of η for this radio/X-ray correlation for L X/L Edd > 10-3, is systematically less than that of the case for L X/L Edd < 10-3, which is consistent with the general idea that the jet is often relatively suppressed at the high luminosity phase in black hole X-ray binaries.

  15. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2012-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as future. space-based detectors. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on.the resulting 'gold rush' of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics

  16. Noncommutative black hole thermodynamics

    SciTech Connect

    Banerjee, Rabin; Majhi, Bibhas Ranjan; Samanta, Saurav

    2008-06-15

    We give a general derivation, for any static spherically symmetric metric, of the relation T{sub h}=(K/2{pi}) connecting the black hole temperature (T{sub h}) with the surface gravity (K), following the tunneling interpretation of Hawking radiation. This derivation is valid even beyond the semi-classical regime, i.e. when quantum effects are not negligible. The formalism is then applied to a spherically symmetric, stationary noncommutative Schwarzschild space-time. The effects of backreaction are also included. For such a black hole the Hawking temperature is computed in a closed form. A graphical analysis reveals interesting features regarding the variation of the Hawking temperature (including corrections due to noncommutativity and backreaction) with the small radius of the black hole. The entropy and tunneling rate valid for the leading order in the noncommutative parameter are calculated. We also show that the noncommutative Bekenstein-Hawking area law has the same functional form as the usual one.

  17. Turbulent black holes.

    PubMed

    Yang, Huan; Zimmerman, Aaron; Lehner, Luis

    2015-02-27

    We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability-which is triggered above a certain perturbation amplitude threshold-akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies-a phenomenon reminiscent of the inverse cascade displayed by (2+1)-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids.

  18. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2010-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as the space-based LISA. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on the resulting gold rush of new results that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wove detection, testing general relativity, and astrophysics.

  19. Bringing Black Holes Home

    NASA Astrophysics Data System (ADS)

    Furmann, John M.

    2003-03-01

    Black holes are difficult to study because they emit no light. To overcome this obstacle, scientists are trying to recreate a black hole in the laboratory. The article gives an overview of the theories of Einstein and Hawking as they pertain to the construction of the Large Hadron Collider (LHC) near Geneva, Switzerland, scheduled for completion in 2006. The LHC will create two beams of protons traveling in opposing directions that will collide and create a plethora of scattered elementary particles. Protons traveling in opposite directions at very high velocities may create particles that come close enough to each other to feel their compacted higher dimensions and create a mega force of gravity that can create tiny laboratory-sized black holes for fractions of a second. The experiments carried out with LHC will be used to test modern string theory and relativity.

  20. Black Hole Paradoxes

    NASA Astrophysics Data System (ADS)

    Joshi, Pankaj S.; Narayan, Ramesh

    2016-10-01

    We propose here that the well-known black hole paradoxes such as the information loss and teleological nature of the event horizon are restricted to a particular idealized case, which is the homogeneous dust collapse model. In this case, the event horizon, which defines the boundary of the black hole, forms initially, and the singularity in the interior of the black hole at a later time. We show that, in contrast, gravitational collapse from physically more realistic initial conditions typically leads to the scenario in which the event horizon and space-time singularity form simultaneously. We point out that this apparently simple modification can mitigate the causality and teleological paradoxes, and also lends support to two recently suggested solutions to the information paradox, namely, the ‘firewall’ and ‘classical chaos’ proposals.

  1. Slowly balding black holes

    SciTech Connect

    Lyutikov, Maxim; McKinney, Jonathan C.

    2011-10-15

    The 'no-hair' theorem, a key result in general relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the no-hair theorem is not formally applicable for black holes formed from the collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively ''frozen in'' the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes N{sub B}=e{Phi}{sub {infinity}}/({pi}c({h_bar}/2{pi})), where {Phi}{sub {infinity}}{approx_equal}2{pi}{sup 2}B{sub NS}R{sub NS}{sup 3}/(P{sub NS}c) is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. We test this theoretical result via 3-dimensional general relativistic plasma simulations of rotating black holes that start with a neutron star dipole magnetic field with no currents initially present outside the event horizon. The black hole's magnetosphere subsequently relaxes to the split-monopole magnetic field geometry with self-generated currents outside the event horizon. The dissipation of the resulting equatorial current sheet leads to a slow loss of the anchored flux tubes, a process that balds the black hole on long resistive time scales rather than the short light-crossing time scales expected from the vacuum no-hair theorem.

  2. Life Inside Black Holes

    NASA Astrophysics Data System (ADS)

    Dokuchaev, Vyacheslav

    2013-11-01

    It is considered the test planet and photon orbits of the third kind inside the black hole (BH), which are stable, periodic and neither come out the BH nor terminate at the central singularity. Interiors of the supermassive BHs may be inhabited by advanced civilizations living on the planets with the third kind orbits. In principle, one can get information from the interiors of BHs by observing their white hole counterparts.

  3. Superfluid Black Holes

    NASA Astrophysics Data System (ADS)

    Hennigar, Robie A.; Mann, Robert B.; Tjoa, Erickson

    2017-01-01

    We present what we believe is the first example of a "λ -line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid 4He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically anti-de Sitter hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  4. Superfluid Black Holes.

    PubMed

    Hennigar, Robie A; Mann, Robert B; Tjoa, Erickson

    2017-01-13

    We present what we believe is the first example of a "λ-line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid ^{4}He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically anti-de Sitter hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  5. Merging Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, Joan; Baker, John G.; Kelly, Bernard J.; vanMeter, James R.

    2010-01-01

    Black-hole mergers take place in regions of very strong and dynamical gravitational fields, and are among the strongest sources of gravitational radiation. Probing these mergers requires solving the full set of Einstein's equations of general relativity numerically. For more than 40 years, progress towards this goal has been very slow, as numerical relativists encountered a host of difficult problems. Recently, several breakthroughs have led to dramatic progress, enabling stable and accurate calculations of black-hole mergers. This article presents an overview of this field, including impacts on astrophysics and applications in gravitational wave data analysis.

  6. Characterizing Black Hole Mergers

    NASA Technical Reports Server (NTRS)

    Baker, John; Boggs, William Darian; Kelly, Bernard

    2010-01-01

    Binary black hole mergers are a promising source of gravitational waves for interferometric gravitational wave detectors. Recent advances in numerical relativity have revealed the predictions of General Relativity for the strong burst of radiation generated in the final moments of binary coalescence. We explore features in the merger radiation which characterize the final moments of merger and ringdown. Interpreting the waveforms in terms of an rotating implicit radiation source allows a unified phenomenological description of the system from inspiral through ringdown. Common features in the waveforms allow quantitative description of the merger signal which may provide insights for observations large-mass black hole binaries.

  7. Euclidean black hole vortices

    NASA Technical Reports Server (NTRS)

    Dowker, Fay; Gregory, Ruth; Traschen, Jennie

    1991-01-01

    We argue the existence of solutions of the Euclidean Einstein equations that correspond to a vortex sitting at the horizon of a black hole. We find the asymptotic behaviors, at the horizon and at infinity, of vortex solutions for the gauge and scalar fields in an abelian Higgs model on a Euclidean Schwarzschild background and interpolate between them by integrating the equations numerically. Calculating the backreaction shows that the effect of the vortex is to cut a slice out of the Schwarzschild geometry. Consequences of these solutions for black hole thermodynamics are discussed.

  8. Nonisolated dynamic black holes and white holes

    SciTech Connect

    McClure, M. L.; Anderson, Kaem; Bardahl, Kirk

    2008-05-15

    Modifying the Kerr-Schild transformation used to generate black and white hole spacetimes, new dynamic black and white holes are obtained using a time-dependent Kerr-Schild scalar field. Physical solutions are found for black holes that shrink with time and for white holes that expand with time. The black hole spacetimes are physical only in the vicinity of the black hole, with the physical region increasing in radius with time. The white hole spacetimes are physical throughout. Unlike the standard Schwarzschild solution the singularities are nonisolated, since the time dependence introduces a mass-energy distribution. The surfaces in the metrics where g{sub tt}=g{sup rr}=0 are dynamic, moving inward with time for the black holes and outward for the white holes, which leads to a question of whether these spacetimes truly have event horizons--a problem shared with Vaidya's cosmological black hole spacetimes. By finding a surface that shrinks or expands at the same rate as the null geodesics move, and within which null geodesics move inward or outward faster than the surfaces shrink or expand, respectively, it is verified that these do in fact behave like black and white holes.

  9. Aspects of hairy black holes

    SciTech Connect

    Anabalón, Andrés; Astefanesei, Dumitru

    2015-03-26

    We review the existence of exact hairy black holes in asymptotically flat, anti-de Sitter and de Sitter space-times. We briefly discuss the issue of stability and the charging of the black holes with a Maxwell field.

  10. Black hole magnetospheres

    SciTech Connect

    Nathanail, Antonios; Contopoulos, Ioannis

    2014-06-20

    We investigate the structure of the steady-state force-free magnetosphere around a Kerr black hole in various astrophysical settings. The solution Ψ(r, θ) depends on the distributions of the magnetic field line angular velocity ω(Ψ) and the poloidal electric current I(Ψ). These are obtained self-consistently as eigenfunctions that allow the solution to smoothly cross the two singular surfaces of the problem, the inner light surface inside the ergosphere, and the outer light surface, which is the generalization of the pulsar light cylinder. Magnetic field configurations that cross both singular surfaces (e.g., monopole, paraboloidal) are uniquely determined. Configurations that cross only one light surface (e.g., the artificial case of a rotating black hole embedded in a vertical magnetic field) are degenerate. We show that, similar to pulsars, black hole magnetospheres naturally develop an electric current sheet that potentially plays a very important role in the dissipation of black hole rotational energy and in the emission of high-energy radiation.

  11. When Black Holes Collide

    NASA Technical Reports Server (NTRS)

    Baker, John

    2010-01-01

    Among the fascinating phenomena predicted by General Relativity, Einstein's theory of gravity, black holes and gravitational waves, are particularly important in astronomy. Though once viewed as a mathematical oddity, black holes are now recognized as the central engines of many of astronomy's most energetic cataclysms. Gravitational waves, though weakly interacting with ordinary matter, may be observed with new gravitational wave telescopes, opening a new window to the universe. These observations promise a direct view of the strong gravitational dynamics involving dense, often dark objects, such as black holes. The most powerful of these events may be merger of two colliding black holes. Though dark, these mergers may briefly release more energy that all the stars in the visible universe, in gravitational waves. General relativity makes precise predictions for the gravitational-wave signatures of these events, predictions which we can now calculate with the aid of supercomputer simulations. These results provide a foundation for interpreting expect observations in the emerging field of gravitational wave astronomy.

  12. Rotating black hole hair

    NASA Astrophysics Data System (ADS)

    Gregory, Ruth; Kubizňák, David; Wills, Danielle

    2013-06-01

    A Kerr black hole sporting cosmic string hair is studied in the context of the abelian Higgs model vortex. It is shown that such a system displays much richer phenomenology than its static Schwarzschild or Reissner-Nordstrom cousins, for example, the rotation generates a near horizon `electric' field. In the case of an extremal rotating black hole, two phases of the Higgs hair are possible: large black holes exhibit standard hair, with the vortex piercing the event horizon. Small black holes on the other hand, exhibit a flux-expelled solution, with the gauge and scalar field remaining identically in their false vacuum state on the event horizon. This solution however is extremely sensitive to confirm numerically, and we conjecture that it is unstable due to a supperradiant mechanism similar to the Kerr-adS instability. Finally, we compute the gravitational back reaction of the vortex, which turns out to be far more nuanced than a simple conical deficit. While the string produces a conical effect, it is conical with respect to a local co-rotating frame, not with respect to the static frame at infinity.

  13. Octonionic black holes

    NASA Astrophysics Data System (ADS)

    Bossard, Guillaume

    2012-05-01

    Using algebraic tools inspired by the study of nilpotent orbits in simple Lie algebras, we obtain a large class of solutions describing interacting non-BPS black holes in {N} = 8 supergravity, which depend on 44 harmonic functions. For this purpose, we consider a truncation {E_{{{6}({6})}}}/S{p_{{c}}}( {8,{R}} ) subset {E_{{{8}({8})}}}/{{Spin}}_{{c}}^{ * }( {16} ) of the non-linear sigma model describing stationary solutions of the theory, which permits a reduction of algebraic computations to the multiplication of 27 by 27 matrices. The lift to {N} = 8 supergravity is then carried out without loss of information by using a pertinent representation of the moduli parametrizing E7(7)/SUc (8) in terms of complex valued Hermitian matrices over the split octonions, which generalise the projective coordinates of exceptional special K¨ahler manifolds. We extract the electromagnetic charges, mass and angular momenta of the solutions, and exhibit the duality invariance of the black holes distance separations. We discuss in particular a new type of interaction which appears when interacting non-BPS black holes are not aligned. Finally we will explain the possible generalisations toward the description of the most general stationary black hole solutions of {N} = 8 supergravity.

  14. Towards noncommutative quantum black holes

    SciTech Connect

    Lopez-Dominguez, J. C.; Obregon, O.; Sabido, M.; Ramirez, C.

    2006-10-15

    In this paper we study noncommutative black holes. We use a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate the Hawking's temperature and entropy for the noncommutative Schwarzschild black hole.

  15. Black-hole astrophysics

    SciTech Connect

    Bender, P.; Bloom, E.; Cominsky, L.

    1995-07-01

    Black-hole astrophysics is not just the investigation of yet another, even if extremely remarkable type of celestial body, but a test of the correctness of the understanding of the very properties of space and time in very strong gravitational fields. Physicists` excitement at this new prospect for testing theories of fundamental processes is matched by that of astronomers at the possibility to discover and study a new and dramatically different kind of astronomical object. Here the authors review the currently known ways that black holes can be identified by their effects on their neighborhood--since, of course, the hole itself does not yield any direct evidence of its existence or information about its properties. The two most important empirical considerations are determination of masses, or lower limits thereof, of unseen companions in binary star systems, and measurement of luminosity fluctuations on very short time scales.

  16. Black hole binaries and microquasars

    NASA Astrophysics Data System (ADS)

    Zhang, Shuang-Nan

    2013-12-01

    This is a general review on the observations and physics of black hole X-ray binaries and microquasars, with the emphasize on recent developments in the high energy regime. The focus is put on understanding the accretion flows and measuring the parameters of black holes in them. It includes mainly two parts: i) Brief review of several recent review article on this subject; ii) Further development on several topics, including black hole spin measurements, hot accretion flows, corona formation, state transitions and thermal stability of standard think disk. This is thus not a regular bottom-up approach, which I feel not necessary at this stage. Major effort is made in making and incorporating from many sources useful plots and illustrations, in order to make this article more comprehensible to non-expert readers. In the end I attempt to make a unification scheme on the accretion-outflow (wind/jet) connections of all types of accreting BHs of all accretion rates and all BH mass scales, and finally provide a brief outlook.

  17. Black Hole Spills Kaleidoscope of Color

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This new false-colored image from NASA's Hubble, Chandra and Spitzer space telescopes shows a giant jet of particles that has been shot out from the vicinity of a type of supermassive black hole called a quasar. The jet is enormous, stretching across more than 100,000 light-years of space -- a size comparable to our own Milky Way galaxy!

    Quasars are among the brightest objects in the universe. They consist of supermassive black holes surrounded by turbulent material, which is being heated up as it is dragged toward the black hole. This hot material glows brilliantly, and some of it gets blown off into space in the form of powerful jets.

    The jet pictured here is streaming out from the first known quasar, called 3C273, discovered in 1963. A kaleidoscope of colors represents the jet's assorted light waves. X-rays, the highest-energy light in the image, are shown at the far left in blue (the black hole itself is well to the left of the image). The X-rays were captured by Chandra. As you move from left to right, the light diminishes in energy, and wavelengths increase in size. Visible light recorded by Hubble is displayed in green, while infrared light caught by Spitzer is red. Areas where visible and infrared light overlap appear yellow.

  18. Black Holes in String Theory

    NASA Astrophysics Data System (ADS)

    Bena, Iosif; El-Showk, Sheer; Vercnocke, Bert

    These lectures notes provide a fast-track introduction to modern developments in black hole physics within string theory, including microscopic computations of the black hole entropy as well as construction and quantization of microstates using supergravity. These notes are largely self-contained and should be accessible to students at an early PhD or Masters level. Topics covered include the black holes in supergravity, D-branes, Strominger-Vafa's computation of the black hole entropy via D-branes, AdS-CFT and its applications to black hole phyisics, multicenter solutions, and the geometric quantization of the latter.

  19. Galaxies of all Shapes Host Black Holes

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This artist's concept illustrates the two types of spiral galaxies that populate our universe: those with plump middles, or central bulges (upper left), and those lacking the bulge (foreground).

    New observations from NASA's Spitzer Space Telescope provide strong evidence that the slender, bulgeless galaxies can, like their chubbier counterparts, harbor supermassive black holes at their cores. Previously, astronomers thought that a galaxy without a bulge could not have a supermassive black hole. In this illustration, jets shooting away from the black holes are depicted as thin streams.

    The findings are reshaping theories of galaxy formation, suggesting that a galaxy's 'waistline' does not determine whether it will be home to a big black hole.

  20. Black Hole Observations - Towards the Event Horizon

    NASA Astrophysics Data System (ADS)

    Britzen, Silke

    Black Holes are probably the most elusive solutions of Einstein's theory of General Relativity. Despite numerous observations of the direct galactic environment and indirect influence of astrophysical black holes (e.g. jets, variable emission across the wavelength spectrum, feedback processes, etc.) -- a direct proof of their existence is still lacking. This article highlights some aspects deduced from many observations and concentrates on the experimental results with regard to black holes with masses from millions to billions of solar masses. The focus will be on the challenges and remaining questions. The Event Horizon Telescopce (EHT) project to image the photon sphere of Sgr A* and its potential is briefly sketched. This instrumental approach shall lead to highest resolution observations of the supermassive black hole at the center of the Milky Way (Sgr A*).

  1. Magnonic Black Holes.

    PubMed

    Roldán-Molina, A; Nunez, Alvaro S; Duine, R A

    2017-02-10

    We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons-the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.

  2. Magnonic Black Holes

    NASA Astrophysics Data System (ADS)

    Roldán-Molina, A.; Nunez, Alvaro S.; Duine, R. A.

    2017-02-01

    We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons—the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.

  3. Prisons of light : black holes

    NASA Astrophysics Data System (ADS)

    Ferguson, Kitty

    What is a black hole? Could we survive a visit to one -- perhaps even venture inside? Have we yet discovered any real black holes? And what do black holes teach us about the mysteries of our Universe? These are just a few of the tantalizing questions examined in this tour-de-force, jargon-free review of one of the most fascinating topics in modern science. In search of the answers, we trace a star from its birth to its death throes, take a hypothetical journey to the border of a black hole and beyond, spend time with some of the world's leading theoretical physicists and astronomers, and take a whimsical look at some of the wild ideas black holes have inspired. Prisons of Light - Black Holes is comprehensive and detailed. Yet Kitty Ferguson's lightness of touch and down-to-earth analogies set this book apart from all others on black holes and make it a wonderfully stimulating and entertaining read.

  4. Black Holes and Firewalls

    NASA Astrophysics Data System (ADS)

    Polchinski, Joseph

    2015-04-01

    Our modern understanding of space, time, matter, and even reality itself arose from the three great revolutions of the early twentieth century: special relativity, general relativity, and quantum mechanics. But a century later, this work is unfinished. Many deep connections have been discovered, but the full form of a unified theory incorporating all three principles is not known. Thought experiments and paradoxes have often played a key role in figuring out how to fit theories together. For the unification of general relativity and quantum mechanics, black holes have been an important arena. I will talk about the quantum mechanics of black holes, the information paradox, and the latest version of this paradox, the firewall. The firewall points to a conflict between our current theories of spacetime and of quantum mechanics. It may lead to a new understanding of how these are connected, perhaps based on quantum entanglement.

  5. Perspectives: Black Holes

    NASA Technical Reports Server (NTRS)

    Dolan, Joseph F.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    When asked to discuss Cyg XR-1, E. E. Salpeter once concluded, 'A black hole in Cyg X(R)-1 is the most conservative hypothesis.' Recent observations now make it likely that a black hole in Cyg XR-1 is the only hypothesis tenable. Chandrasekhar first showed that compact stars - those with the inward force of gravity on their outer layers balanced by the pressure generated by the Pauli exclusion principle acting on its electrons (in white dwarfs) or nucleons (in neutron stars) - have a maximum mass. Equilibrium is achieved at a minimum of the total energy of the star, which is the sum of the positive Fermi energy and the negative gravitational energy. The maximum mass attainable in equilibrium is found by setting E = 0: M(max) = 1.5 M(Sun). If the mass of the star is larger than this, then E can be decreased without bound by decreasing the star's radius and increasing its (negative) gravitational energy. No equilibrium value of the radius exist, and general relativity predicts that gravitational collapse to a point occurs. This point singularity is a black hole.

  6. Making Supermassive Black Holes Spin

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-12-01

    Where does the angular momentum come from that causes supermassive black holes (SMBHs) to spin on their axes and launch powerful jets? A new study of nearby SMBHs may help to answer this question.High-mass SMBHs are thought to form when two galaxies collide and the SMBHs at their centers merge. [NASA/Hubble Heritage Team (STScI)]High- vs. Low-Mass MonstersObservational evidence suggests a dichotomy between low-mass SMBHs (those with 106-7 M) and high-mass ones (those with 108-10 M). High-mass SMBHs are thought to form via the merger of two smaller black holes, and the final black hole is likely spun up by the rotational dynamics of the merger. But what spins up low-mass SMBHs, which are thought to build up very gradually via accretion?A team of scientists led by Jing Wang (National Astronomical Observatories, Chinese Academy of Sciences) have attempted to address this puzzle by examining the properties of the galaxies hosting low-mass SMBHs.A Sample of Neighboring SMBHsWang and collaborators began by constructing a sample of radio-selected nearby Seyfert 2 galaxies: those galaxies in which the stellar population and morphology of the host galaxy are visible to us, instead of being overwhelmed by continuum emission from the galaxys active nucleus.An example of a galaxy with a concentrated, classical bulge (M87; top) and a one with a disk-like pseudo bulge (Triangulum Galaxy; bottom). The authors find that for galaxies hosting low-mass SMBHs, those with more disk-like bulges appear to have more powerful radio jets. [Top: NASA/Hubble Heritage Team (STScI), Bottom: Hewholooks]From this sample, the authors then selected 31 galaxies that have low-mass SMBHs at their centers, as measured using the surrounding stellar dynamics. Wang and collaborators cataloged radio information revealing properties of the powerful jets launched by the SMBHs, and they analyzed the host galaxies properties by modeling their brightness profiles.Spin-Up From Accreting GasBy examining this

  7. Episodic Jet Power Extracted from a Spinning Black Hole Surrounded by a Neutrino-dominated Accretion Flow in Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    Cao, Xinwu; Liang, En-Wei; Yuan, Ye-Fei

    2014-07-01

    It was suggested that the relativistic jets in gamma-ray bursts (GRBs) are powered via the Blandford-Znajek (BZ) mechanism or the annihilation of neutrinos and anti-neutrinos from a neutrino cooling-dominated accretion flow (NDAF). The advection and diffusion of the large-scale magnetic field of an NDAF is calculated, and the external magnetic field is found to be dragged inward efficiently by the accretion flow for a typical magnetic Prandtl number \\mathscr{P}_m=η /ν ˜ 1. The maximal BZ jet power can be ~1053-1054 erg s-1 for an extreme Kerr black hole, if an external magnetic field with 1014 Gauss is advected by the NDAF. This is roughly consistent with the field strength of the disk formed after a tidal disrupted magnetar. The accretion flow near the black hole horizon is arrested by the magnetic field if the accretion rate is below than a critical value for a given external field. The arrested accretion flow fails to drag the field inward and the field strength decays, and then the accretion re-starts, which leads to oscillating accretion. The typical timescale of such episodic accretion is of an order of one second. This can qualitatively explain the observed oscillation in the soft extended emission of short-type GRBs.

  8. X-Ray Jet Emission from the Black Hole X-Ray Binary XTE J1550-564 with Chandra in 2000

    NASA Astrophysics Data System (ADS)

    Tomsick, John A.; Corbel, Stéphane; Fender, Rob; Miller, Jon M.; Orosz, Jerome A.; Tzioumis, Tasso; Wijnands, Rudy; Kaaret, Philip

    2003-01-01

    We have discovered an X-ray jet due to material ejected from the black hole X-ray transient XTE J1550-564. The discovery was first reported in 2002 by Corbel and coworkers, and here we present an analysis of the three Chandra observations made between 2000 June and September. For these observations, a source is present that moves in an eastward direction away from the point source associated with the compact object. The separation between the new source and the compact object changes from 21.3" in June to 23.4" in September, implying a proper motion of 21.2+/-7.2 mas day-1, a projected separation of 0.31-0.85 pc, and an apparent jet velocity between 0.34+/-0.12 and 0.93+/-0.32 times the speed of light for a source distance range of d=2.8-7.6 kpc. These observations represent the first time that an X-ray jet proper-motion measurement has been obtained for any accretion-powered Galactic or extragalactic source. While this work deals with the jet to the east of the compact object, the western jet has also been detected in the X-ray and radio bands. The most likely scenario is that the eastern jet is the approaching jet and that the jet material was ejected from the black hole in 1998. Along with a 1998 VLBI proper-motion measurement, the Chandra proper motion indicates that the eastern jet decelerated between 1998 and 2000. There is evidence that the eastern jet is extended by +/-2"-3" in the direction of the proper motion. The upper limit on the source extension in the perpendicular direction is +/-1.5", which corresponds to a jet opening angle of less than 7.5d. The X-ray jet energy spectrum is well but not uniquely described by a power law with an energy index of α=-0.8+/-0.4 (Sν~να) and interstellar absorption. The eastern jet was also detected in the radio band during an observation made within 7.4 days of the June Chandra observation. The overall radio flux level is consistent with an extrapolation of the X-ray power law with α=-0.6. The 0.3-8 keV X-ray jet

  9. Black Holes in Higher Dimensions

    NASA Astrophysics Data System (ADS)

    Horowitz, Gary T.

    2012-04-01

    List of contributors; Preface; Part I. Introduction: 1. Black holes in four dimensions Gary Horowitz; Part II. Five Dimensional Kaluza-Klein Theory: 2. The Gregory-Laflamme instability Ruth Gregory; 3. Final state of Gregory-Laflamme instability Luis Lehner and Frans Pretorius; 4. General black holes in Kaluza-Klein theory Gary Horowitz and Toby Wiseman; Part III. Higher Dimensional Solutions: 5. Myers-Perry black holes Rob Myers; 6. Black rings Roberto Emparan and Harvey Reall; Part IV. General Properties: 7. Constraints on the topology of higher dimensional black holes Greg Galloway; 8. Blackfolds Roberto Emparan; 9. Algebraically special solutions in higher dimensions Harvey Reall; 10. Numerical construction of static and stationary black holes Toby Wiseman; Part V. Advanced Topics: 11. Black holes and branes in supergravity Don Marolf; 12. The gauge/gravity duality Juan Maldacena; 13. The fluid/gravity correspondence Veronika Hubeny, Mukund Rangamani and Shiraz Minwalla; 14. Horizons, holography and condensed matter Sean Hartnoll; Index.

  10. Black Holes Have Simple Feeding Habits

    NASA Astrophysics Data System (ADS)

    2008-06-01

    . "We thought this was the case, but up until now we haven't been able to nail it." People Who Read This Also Read... NASA’s Swift Satellite Catches First Supernova in The Act of Exploding Jet Power and Black Hole Assortment Revealed in New Chandra Image Chandra Data Reveal Rapidly Whirling Black Holes Ghostly Glow Reveals a Hidden Class of Long-Wavelength Radio Emitters The model that Markoff and her colleagues used to study the black holes includes a faint disk of material spinning around the black hole. This structure would mainly produce X-rays and optical light. A region of hot gas around the black hole would be seen largely in ultraviolet and X-ray light. A large contribution to both the radio and X-ray light comes from jets generated by the black hole. Multi-wavelength data is needed to disentangle these overlapping sources of light. "When we look at the data, it turns out that our model works just as well for the giant black hole in M81 as it does for the smaller guys," said Michael Nowak, a coauthor from the Massachusetts Institute of Technology. "Everything around this huge black hole looks just the same except it's almost 10 million times bigger." Among actively feeding black holes the one in M81 is one of the dimmest, presumably because it is "underfed". It is, however, one of the brightest as seen from Earth because of its relative proximity, allowing high quality observations to be made. "It seems like the underfed black holes are the simplest in practice, perhaps because we can see closer to the black hole," said Andrew Young of the University of Bristol in England. "They don't seem to care too much where they get their food from." This work should be useful for predicting the properties of a third, unconfirmed class called intermediate mass black holes, with masses lying between those of stellar and supermassive black holes. Some possible members of this class have been identified, but the evidence is controversial, so specific predictions for the

  11. FEASTING BLACK HOLE BLOWS BUBBLES

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A monstrous black hole's rude table manners include blowing huge bubbles of hot gas into space. At least, that's the gustatory practice followed by the supermassive black hole residing in the hub of the nearby galaxy NGC 4438. Known as a peculiar galaxy because of its unusual shape, NGC 4438 is in the Virgo Cluster, 50 million light-years from Earth. These NASA Hubble Space Telescope images of the galaxy's central region clearly show one of the bubbles rising from a dark band of dust. The other bubble, emanating from below the dust band, is barely visible, appearing as dim red blobs in the close-up picture of the galaxy's hub (the colorful picture at right). The background image represents a wider view of the galaxy, with the central region defined by the white box. These extremely hot bubbles are caused by the black hole's voracious eating habits. The eating machine is engorging itself with a banquet of material swirling around it in an accretion disk (the white region below the bright bubble). Some of this material is spewed from the disk in opposite directions. Acting like high-powered garden hoses, these twin jets of matter sweep out material in their paths. The jets eventually slam into a wall of dense, slow-moving gas, which is traveling at less than 223,000 mph (360,000 kph). The collision produces the glowing material. The bubbles will continue to expand and will eventually dissipate. Compared with the life of the galaxy, this bubble-blowing phase is a short-lived event. The bubble is much brighter on one side of the galaxy's center because the jet smashed into a denser amount of gas. The brighter bubble is 800 light-years tall and 800 light-years across. The observations are being presented June 5 at the American Astronomical Society meeting in Rochester, N.Y. Both pictures were taken March 24, 1999 with the Wide Field and Planetary Camera 2. False colors were used to enhance the details of the bubbles. The red regions in the picture denote the hot gas

  12. X-ray jet emission from the black hole X-ray binary XTE J1550-564 with CHANDRA in 2000

    NASA Astrophysics Data System (ADS)

    Tomsick, J. A.; Corbel, S.; Fender, R. P.; Miller, J. M.; Orosz, J. A.; Tzioumis, T.; Wijnands, R.; Kaaret, P.

    We have discovered an X-ray jet due to material ejected from the black hole X-ray transient XTE J1550-564 (see also the Corbel et al. contribution to these proceedings). We present results from three Chandra observations made between 2000 June and 2000 September. For these observations, a source is present that moves in an eastward direction away from the point source associated with the compact object. The separation between the new source and the compact object changes from 21''.3 in June to 23''.4 in September, implying a proper motion of 21.2 ± 7.2 mas day-1, a projected separation of 0.31-0.85 pc and a jet velocity >0.22c for a source distance range of d = 2.8-7.6 kpc. These observations represent the first time that an X-ray jet proper motion measurement has been obtained for any accretion powered Galactic or extra-galactic source. Along with a 1998 VLBI proper motion measurement, the Chandra proper motion indicates that the jet decelerated between 1998 and 2000. Although we cannot definitively determine the X-ray emission mechanism, a synchrotron origin is viable and may provide the simplest explanation for the observations.

  13. Foundations of Black Hole Accretion Disk Theory.

    PubMed

    Abramowicz, Marek A; Fragile, P Chris

    2013-01-01

    This review covers the main aspects of black hole accretion disk theory. We begin with the view that one of the main goals of the theory is to better understand the nature of black holes themselves. In this light we discuss how accretion disks might reveal some of the unique signatures of strong gravity: the event horizon, the innermost stable circular orbit, and the ergosphere. We then review, from a first-principles perspective, the physical processes at play in accretion disks. This leads us to the four primary accretion disk models that we review: Polish doughnuts (thick disks), Shakura-Sunyaev (thin) disks, slim disks, and advection-dominated accretion flows (ADAFs). After presenting the models we discuss issues of stability, oscillations, and jets. Following our review of the analytic work, we take a parallel approach in reviewing numerical studies of black hole accretion disks. We finish with a few select applications that highlight particular astrophysical applications: measurements of black hole mass and spin, black hole vs. neutron star accretion disks, black hole accretion disk spectral states, and quasi-periodic oscillations (QPOs).

  14. Chaotic Accretion and Merging Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Nixon, Christopher James

    2012-09-01

    The main driver of the work in this thesis is the idea of chaotic accretion in galaxy centres. Most research in this area focuses on orderly or coherent accretion where supermassive black holes or supermassive black hole binaries are fed with gas always possessing the same sense of angular momentum. If instead gas flows in galaxies are chaotic, feeding occurs through randomly oriented depositions of gas. Previous works show that this chaotic mode of feeding can explain some astrophysical phenomena, such as the lack of correlation between host galaxy structure and the direction of jets. It has also been shown that by keeping the black hole spin low this feeding mechanism can grow supermassive black holes from stellar mass seeds. In this thesis I show that it also alleviates the "final parsec problem" by facilitating the merger of two supermassive black holes, and the growth of supermassive black holes through rapid accretion. I also develop the intriguing possibility of breaking a warped disc into two or more distinct planes.

  15. The First Black Holes

    NASA Astrophysics Data System (ADS)

    Abel, T.

    star. Within this wide range of possible initial masses the death of these star will lead very different remnants (Heger and Woosley 2001). In the case of stars with masses larger than 260 solar mass no metals may be released in black holes are the natural outcome. This may be an interesting possibility to form intermediate mass black holes which are attractive seeds to be nurtured to the super-massive black holes observed in the centers of nearby galaxies. However, no metals would be released and it would prove difficult to understand the transition to the formation of low mass metal enriched population II stars. Stars with masses below 140 solar masses would enrich the intergalactic medium as well as form massive black holes. The coincidence of the Kelvin Helmholtz time with our computed accretion times at about 120 solar masses may argue in favor of such smaller masses. These first black holes may well leave the halos in which they formed for even rather modest kick velocities >~ 10 km/s. Nevertheless, up to about one hundred thousand of these first black holes may remain in the Milky Way. The realization that structure formation began within one hundred million years after big bang makes it difficult to study observationally these first crucial steps. Future observatories have hence to focus on larger collecting areas and wavelengths for which the universe is transparent up to redshifts of 30. XEUS offers the chance to open a new window to these so far dark ages. The limiting masses quoted here rely on stellar models of primordial stars that do not include rotation, magnetic fields or mass loss and hence are somewhat uncertain.

  16. Menus for Feeding Black Holes

    NASA Astrophysics Data System (ADS)

    Kocsis, Bence; Loeb, Abraham

    2014-09-01

    Black holes are the ultimate prisons of the Universe, regions of spacetime where the enormous gravity prohibits matter or even light to escape to infinity. Yet, matter falling toward the black holes may shine spectacularly, generating the strongest source of radiation. These sources provide us with astrophysical laboratories of extreme physical conditions that cannot be realized on Earth. This chapter offers a review of the basic menus for feeding matter onto black holes and discusses their observational implications.

  17. Thermodynamics of Accelerating Black Holes.

    PubMed

    Appels, Michael; Gregory, Ruth; Kubizňák, David

    2016-09-23

    We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon-even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability, and phase structure of these black holes.

  18. Black holes and the multiverse

    SciTech Connect

    Garriga, Jaume; Vilenkin, Alexander; Zhang, Jun E-mail: vilenkin@cosmos.phy.tufts.edu

    2016-02-01

    Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive black holes. The mechanism of black hole formation described in this paper is very generic and has important implications for the global structure of the universe. Baby universes inside super-critical black holes inflate eternally and nucleate bubbles of all vacua allowed by the underlying particle physics. The resulting multiverse has a very non-trivial spacetime structure, with a multitude of eternally inflating regions connected by wormholes. If a black hole population with the predicted mass spectrum is discovered, it could be regarded as evidence for inflation and for the existence of a multiverse.

  19. Thermodynamics of Accelerating Black Holes

    NASA Astrophysics Data System (ADS)

    Appels, Michael; Gregory, Ruth; KubizÅák, David

    2016-09-01

    We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon—even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability, and phase structure of these black holes.

  20. Ring Around the Black Hole

    NASA Technical Reports Server (NTRS)

    Wanjek, Christopher

    2003-01-01

    Regardless of size, black holes easily acquire accretion disks. Supermassive black holes can feast on the bountiful interstellar gas in galactic nuclei. Small black holes formed from collapsing stars often belong to binary systems in which a bulging companion star can spill some of its gas into the black hole s reach. In the chaotic mess of the accretion disk, atoms collide with one another. Swirling plasma reaches speeds upward of 10% that of light and glows brightly in many wavebands, particularly in X-rays. Gas gets blown back by a wind of radiation from the inner disk. New material enters the disks from different directions.

  1. How black holes saved relativity

    NASA Astrophysics Data System (ADS)

    Prescod-Weinstein, Chanda

    2016-02-01

    While there have been many popular-science books on the historical and scientific legacy of Albert Einstein's general theory of relativity, a gap exists in the literature for a definitive, accessible history of the theory's most famous offshoot: black holes. In Black Hole, the science writer Marcia Bartusiak aims for a discursive middle ground, writing solely about black holes at a level suitable for both high-school students and more mature readers while also giving some broader scientific context for black-hole research.

  2. Surfing a Black Hole

    NASA Astrophysics Data System (ADS)

    2002-10-01

    Star Orbiting Massive Milky Way Centre Approaches to within 17 Light-Hours [1] Summary An international team of astronomers [2], lead by researchers at the Max-Planck Institute for Extraterrestrial Physics (MPE) , has directly observed an otherwise normal star orbiting the supermassive black hole at the center of the Milky Way Galaxy. Ten years of painstaking measurements have been crowned by a series of unique images obtained by the Adaptive Optics (AO) NAOS-CONICA (NACO) instrument [3] on the 8.2-m VLT YEPUN telescope at the ESO Paranal Observatory. It turns out that earlier this year the star approached the central Black Hole to within 17 light-hours - only three times the distance between the Sun and planet Pluto - while travelling at no less than 5000 km/sec . Previous measurements of the velocities of stars near the center of the Milky Way and variable X-ray emission from this area have provided the strongest evidence so far of the existence of a central Black Hole in our home galaxy and, implicitly, that the dark mass concentrations seen in many nuclei of other galaxies probably are also supermassive black holes. However, it has not yet been possible to exclude several alternative configurations. In a break-through paper appearing in the research journal Nature on October 17th, 2002, the present team reports their exciting results, including high-resolution images that allow tracing two-thirds of the orbit of a star designated "S2" . It is currently the closest observable star to the compact radio source and massive black hole candidate "SgrA*" ("Sagittarius A") at the very center of the Milky Way. The orbital period is just over 15 years. The new measurements exclude with high confidence that the central dark mass consists of a cluster of unusual stars or elementary particles, and leave little doubt of the presence of a supermassive black hole at the centre of the galaxy in which we live . PR Photo 23a/02 : NACO image of the central region of the Milky Way

  3. Search for quantum black hole production in high-invariant-mass lepton+jet final states using pp collisions at √s=8  TeV and the ATLAS detector.

    PubMed

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Stillings, J A; Stockton, M C; Stoebe, M; Stoerig, K; Stoicea, G; Stonjek, S; Stradling, A R; Straessner, A; Strandberg, J; Strandberg, S; Strandlie, A; Strauss, E; Strauss, M; Strizenec, P; Ströhmer, R; Strom, D M; Stroynowski, R; Stucci, S A; Stugu, B; Stumer, I; Stupak, J; Styles, N A; Su, D; Su, J; Subramania, Hs; Subramaniam, R; Succurro, A; Sugaya, Y; Suhr, C; Suk, M; Sulin, V V; Sultansoy, S; Sumida, T; Sun, X; Sundermann, J E; Suruliz, K; Susinno, G; Sutton, M R; Suzuki, Y; Svatos, M; Swedish, S; Swiatlowski, M; Sykora, I; Sykora, T; Ta, D; Tackmann, K; Taenzer, J; Taffard, A; Tafirout, R; Taiblum, N; Takahashi, Y; Takai, H; Takashima, R; Takeda, H; Takeshita, T; Takubo, Y; Talby, M; Talyshev, A A; Tam, J Y C; Tamsett, M C; Tan, K G; Tanaka, J; Tanaka, R; Tanaka, S; Tanaka, S; Tanasijczuk, A J; Tani, K; Tannoury, N; Tapprogge, S; Tarem, S; Tarrade, F; Tartarelli, G F; Tas, P; Tasevsky, M; Tashiro, T; Tassi, E; Tavares Delgado, A; Tayalati, Y; Taylor, C; Taylor, F E; Taylor, G N; Taylor, W; Teischinger, F A; Teixeira Dias Castanheira, M; Teixeira-Dias, P; Temming, K K; Ten Kate, H; Teng, P K; Terada, S; Terashi, K; Terron, J; Terzo, S; Testa, M; Teuscher, R J; Therhaag, J; Theveneaux-Pelzer, T; Thoma, S; Thomas, J P; Thomas-Wilsker, J; Thompson, E N; Thompson, P D; Thompson, P D; Thompson, A S; Thomsen, L A; Thomson, E; Thomson, M; Thong, W M; Thun, R P; Tian, F; Tibbetts, M J; Tic, T; Tikhomirov, V O; Tikhonov, Yu A; Timoshenko, S; Tiouchichine, E; Tipton, P; Tisserant, S; Todorov, T; Todorova-Nova, S; Toggerson, B; Tojo, J; Tokár, S; Tokushuku, K; Tollefson, K; Tomlinson, L; Tomoto, M; Tompkins, L; Toms, K; Topilin, N D; Torrence, E; Torres, H; Torró Pastor, E; Toth, J; Touchard, F; Tovey, D R; Tran, H L; Trefzger, T; Tremblet, L; Tricoli, A; Trigger, I M; Trincaz-Duvoid, S; Tripiana, M F; Triplett, N; Trischuk, W; Trocmé, B; Troncon, C; Trottier-McDonald, M; Trovatelli, M; True, P; Trzebinski, M; Trzupek, A; Tsarouchas, C; Tseng, J C-L; Tsiareshka, P V; Tsionou, D; Tsipolitis, G; Tsirintanis, N; Tsiskaridze, S; Tsiskaridze, V; Tskhadadze, E G; Tsukerman, I I; Tsulaia, V; Tsung, J-W; Tsuno, S; Tsybychev, D; Tua, A; Tudorache, A; Tudorache, V; Tuna, A N; Tupputi, S A; Turchikhin, S; Turecek, D; Turk Cakir, I; Turra, R; Tuts, P M; Tykhonov, A; Tylmad, M; Tyndel, M; Uchida, K; Ueda, I; Ueno, R; Ughetto, M; Ugland, M; Uhlenbrock, M; Ukegawa, F; Unal, G; Undrus, A; Unel, G; Ungaro, F C; Unno, Y; Urbaniec, D; Urquijo, P; Usai, G; Usanova, A; Vacavant, L; Vacek, V; Vachon, B; Valencic, N; Valentinetti, S; Valero, A; Valery, L; Valkar, S; Valladolid Gallego, E; Vallecorsa, S; Valls Ferrer, J A; Van Berg, R; Van Der Deijl, P C; van der Geer, R; van der Graaf, H; Van Der Leeuw, R; van der Ster, D; van Eldik, N; van Gemmeren, P; Van Nieuwkoop, J; van Vulpen, I; van Woerden, M C; Vanadia, M; Vandelli, W; Vaniachine, A; Vankov, P; Vannucci, F; Vardanyan, G; Vari, R; Varnes, E W; Varol, T; Varouchas, D; Vartapetian, A; Varvell, K E; Vassilakopoulos, V I; Vazeille, F; Vazquez Schroeder, T; Veatch, J; Veloso, F; Veneziano, S; Ventura, A; Ventura, D; Venturi, M; Venturi, N; Venturini, A; Vercesi, V; Verducci, M; Verkerke, W; Vermeulen, J C; Vest, A; Vetterli, M C; Viazlo, O; Vichou, I; Vickey, T; Vickey Boeriu, O E; Viehhauser, G H A; Viel, S; Vigne, R; Villa, M; Villaplana Perez, M; Vilucchi, E; Vincter, M G; Vinogradov, V B; Virzi, J; Vitells, O; Vivarelli, I; Vives Vaque, F; Vlachos, S; Vladoiu, D; Vlasak, M; Vogel, A; Vokac, P; Volpi, G; Volpi, M; von der Schmitt, H; von Radziewski, H; von Toerne, E; Vorobel, V; Vos, M; Voss, R; Vossebeld, J H; Vranjes, N; Vranjes Milosavljevic, M; Vrba, V; Vreeswijk, M; Vu Anh, T; Vuillermet, R; Vukotic, I; Vykydal, Z; Wagner, W; Wagner, P; Wahrmund, S; Wakabayashi, J; Walder, J; Walker, R; Walkowiak, W; Wall, R; Waller, P; Walsh, B; Wang, C; Wang, C; Wang, H; Wang, H; Wang, J; Wang, J; Wang, K; Wang, R; Wang, S M; Wang, T; Wang, X; Warburton, A; Ward, C P; Wardrope, D R; Warsinsky, M; Washbrook, A; Wasicki, C; Watanabe, I; Watkins, P M; Watson, A T; Watson, I J; Watson, M F; Watts, G; Watts, S; Waugh, A T; Waugh, B M; Webb, S; Weber, M S; Weber, S W; Webster, J S; Weidberg, A R; Weigell, P; Weingarten, J; Weiser, C; Weits, H; Wells, P S; Wenaus, T; Wendland, D; Weng, Z; Wengler, T; Wenig, S; Wermes, N; Werner, M; Werner, P; Wessels, M; Wetter, J; Whalen, K; White, A; White, M J; White, R; White, S; Whiteson, D; Whittington, D; Wicke, D; Wickens, F J; Wiedenmann, W; Wielers, M; Wienemann, P; Wiglesworth, C; Wiik-Fuchs, L A M; Wijeratne, P A; Wildauer, A; Wildt, M A; Wilkens, H G; Will, J Z; Williams, H H; Williams, S; Willocq, S; Wilson, J A; Wilson, A; Wingerter-Seez, I; Winkelmann, S; Winklmeier, F; Wittgen, M; Wittig, T; Wittkowski, J; Wollstadt, S J; Wolter, M W; Wolters, H; Wosiek, B K; Wotschack, J; Woudstra, M J; Wozniak, K W; Wraight, K; Wright, M; Wu, S L; Wu, X; Wu, Y; Wulf, E; Wyatt, T R; Wynne, B M; Xella, S; Xiao, M; Xu, D; Xu, L; Yabsley, B; Yacoob, S; Yamada, M; Yamaguchi, H; Yamaguchi, Y; Yamamoto, A; Yamamoto, K; Yamamoto, S; Yamamura, T; Yamanaka, T; Yamauchi, K; Yamazaki, Y; Yan, Z; Yang, H; Yang, H; Yang, U K; Yang, Y; Yanush, S; Yao, L; Yasu, Y; Yatsenko, E; Yau Wong, K H; Ye, J; Ye, S; Yen, A L; Yildirim, E; Yilmaz, M; Yoosoofmiya, R; Yorita, K; Yoshida, R; Yoshihara, K; Young, C; Young, C J S; Youssef, S; Yu, D R; Yu, J; Yu, J M; Yu, J; Yuan, L; Yurkewicz, A; Zabinski, B; Zaidan, R; Zaitsev, A M; Zaman, A; Zambito, S; Zanello, L; Zanzi, D; Zaytsev, A; Zeitnitz, C; Zeman, M; Zemla, A; Zengel, K; Zenin, O; Zeniš, T; Zerwas, D; Zevi Della Porta, G; Zhang, D; Zhang, H; Zhang, J; Zhang, L; Zhang, X; Zhang, Z; Zhao, Z; Zhemchugov, A; Zhong, J; Zhou, B; Zhou, L; Zhou, N; Zhu, C G; Zhu, H; Zhu, J; Zhu, Y; Zhuang, X; Zibell, A; Zieminska, D; Zimin, N I; Zimmermann, C; Zimmermann, R; Zimmermann, S; Zimmermann, S; Zinonos, Z; Ziolkowski, M; Zitoun, R; Zivković, L; Zobernig, G; Zoccoli, A; Zur Nedden, M; Zurzolo, G; Zutshi, V; Zwalinski, L

    2014-03-07

    This Letter presents a search for quantum black-hole production using 20.3 fb-1 of data collected with the ATLAS detector in pp collisions at the LHC at √s = 8 TeV. The quantum black holes are assumed to decay into a final state characterized by a lepton (electron or muon) and a jet. In either channel, no event with a lepton-jet invariant mass of 3.5 TeV or more is observed, consistent with the expected background. Limits are set on the product of cross sections and branching fractions for the lepton+jet final states of quantum black holes produced in a search region for invariant masses above 1 TeV. The combined 95% confidence level upper limit on this product for quantum black holes with threshold mass above 3.5 TeV is 0.18 fb. This limit constrains the threshold quantum black-hole mass to be above 5.3 TeV in the model considered.

  4. The physical fundamental plane of black hole activity: revisited

    NASA Astrophysics Data System (ADS)

    Liu, Xiang; Han, Zhenhua; Zhang, Zhen

    2016-01-01

    The correlation between the jet power and accretion disk luminosity is investigated for active galactic nuclei (AGNs) and black hole X-ray binaries (BHXBs) from the literature. The power-law correlation index is steep (μ˜1.0 -1.4) for radio loud quasars and the `outliers' of BHXBs, and it is flatter (μ˜ 0.3 -0.6) for radio loud galaxies and the standard BHXBs. The steep-index groups are mostly at higher accretion rates (peaked at Eddington ratio > 0.01) and the flatter-index groups are at relatively low accretion rates (peaked at Eddington ratio < 0.01), implying that the former groups could be dominated by the inner disk accretion of black hole, while the jet in latter groups would be a hybrid production of the accretion and black hole spin. We could still have a fundamental plane of black hole activity for the BHXBs and AGNs with diverse (maybe two kinds of) correlation indices. It is noted that the fundamental plane of black hole activity should be referred to the correlation between the jet power and disk luminosity or equivalently to the correlation between jet power, Eddington ratio and black hole mass, rather than the jet power, disk luminosity and black hole mass.

  5. Black-Hole Feedback in Quasars

    NASA Video Gallery

    This animation illustrates how black-hole feedback works in quasars. Dense gas and dust in the center simultaneously fuels the black hole and shrouds it from view. The black-hole wind propels large...

  6. Prisons of Light - Black Holes

    NASA Astrophysics Data System (ADS)

    Ferguson, Kitty

    1998-05-01

    In this jargon-free review of one of the most fascinating topics in modern science, acclaimed science writer Kitty Ferguson examines the discovery of black holes, their nature, and what they can teach us about the mysteries of the universe. In search of the answers, we trace a star from its birth to its death throes, take a hypothetical journey to the border of a black hole and beyond, spend time with some of the world's leading theoretical physicists and astronomers, and take a whimsical look at some of the wild ideas black holes have inspired. Prisons of Light--Black Holes is comprehensive and detailed. Yet Kitty Ferguson's lightness of touch and down-to-earth analogies set this book apart from all others on black holes and make it a wonderfully stimulating and entertaining read.

  7. Numerical Simulation of Black Holes

    NASA Astrophysics Data System (ADS)

    Teukolsky, Saul

    2003-04-01

    Einstein's equations of general relativity are prime candidates for numerical solution on supercomputers. There is some urgency in being able to carry out such simulations: Large-scale gravitational wave detectors are now coming on line, and the most important expected signals cannot be predicted except numerically. Problems involving black holes are perhaps the most interesting, yet also particularly challenging computationally. One difficulty is that inside a black hole there is a physical singularity that cannot be part of the computational domain. A second difficulty is the disparity in length scales between the size of the black hole and the wavelength of the gravitational radiation emitted. A third difficulty is that all existing methods of evolving black holes in three spatial dimensions are plagued by instabilities that prohibit long-term evolution. I will describe the ideas that are being introduced in numerical relativity to deal with these problems, and discuss the results of recent calculations of black hole collisions.

  8. String-Corrected Black Holes

    SciTech Connect

    Hubeny, Veronika; Maloney, Alexander; Rangamani, Mukund

    2005-02-07

    We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect -- the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive! The magnitude of this effect is related to the size of the compactification manifold.

  9. When Charged Black Holes Merge

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-08-01

    Most theoretical models assume that black holes arent charged. But a new study shows that mergers of charged black holes could explain a variety of astrophysical phenomena, from fast radio bursts to gamma-ray bursts.No HairThe black hole no hair theorem states that all black holes can be described by just three things: their mass, their spin, and their charge. Masses and spins have been observed and measured, but weve never measured the charge of a black hole and its widely believed that real black holes dont actually have any charge.That said, weve also never shown that black holes dont have charge, or set any upper limits on the charge that they might have. So lets suppose, for a moment, that its possible for a black hole to be charged. How might that affect what we know about the merger of two black holes? A recent theoretical study by Bing Zhang (University of Nevada, Las Vegas) examines this question.Intensity profile of a fast radio burst, a sudden burst of radio emission that lasts only a few milliseconds. [Swinburne Astronomy Productions]Driving TransientsZhangs work envisions a pair of black holes in a binary system. He argues that if just one of the black holes carries charge possibly retained by a rotating magnetosphere then it may be possible for the system to produce an electromagnetic signal that could accompany gravitational waves, such as a fast radio burst or a gamma-ray burst!In Zhangs model, the inspiral of the two black holes generates a global magnetic dipole thats perpendicular to the plane of the binarys orbit. The magnetic flux increases rapidly as the separation between the black holes decreases, generating an increasingly powerful magnetic wind. This wind, in turn, can give rise to a fast radio burst or a gamma-ray burst, depending on the value of the black holes charge.Artists illustration of a short gamma-ray burst, thought to be caused by the merger of two compact objects. [ESO/A. Roquette]Zhang calculates lower limits on the charge

  10. Black hole final state conspiracies

    NASA Astrophysics Data System (ADS)

    McInnes, Brett

    2009-01-01

    The principle that unitarity must be preserved in all processes, no matter how exotic, has led to deep insights into boundary conditions in cosmology and black hole theory. In the case of black hole evaporation, Horowitz and Maldacena were led to propose that unitarity preservation can be understood in terms of a restriction imposed on the wave function at the singularity. Gottesman and Preskill showed that this natural idea only works if one postulates the presence of “conspiracies” between systems just inside the event horizon and states at much later times, near the singularity. We argue that some AdS black holes have unusual internal thermodynamics, and that this may permit the required “conspiracies” if real black holes are described by some kind of sum over all AdS black holes having the same entropy.

  11. Grumblings from an Awakening Black Hole

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-11-01

    In June of this year, after nearly three decades of sleep, the black hole V404 Cygni woke up and began grumbling. Scientists across the globe scrambled to observe the sudden flaring activity coming from this previously peaceful black hole. And now were getting the first descriptions of what weve learned from V404 Cygs awakening!Sudden OutburstV404 Cyg is a black hole of roughly nine solar masses, and its in a binary system with a low-mass star. The black hole pulls a stream of gas from the star, which then spirals in around the black hole, forming an accretion disk. Sometimes the material simply accumulates in the disk but every two or three decades, the build-up of gas suddenly rushes toward the black hole as if a dam were bursting.The sudden accretion in these events causes outbursts of activity from the black hole, its flaring easily visible to us. The last time V404 Cyg exhibited such activity was in 1989, and its been rather quiet since then. Our telescopes are of course much more powerful and sensitive now, nearly three decades later so when the black hole woke up and began flaring in June, scientists were delighted at the chance to observe it.The high variability of V404 Cyg is evident in this example set of spectra, where time increases from the bottom panel to the top. [King et al. 2015]Led by Ashley King (Einstein Fellow at Stanford University), a team of scientists observed V404 Cyg with the Chandra X-ray Observatory, obtaining spectra of the black hole during its outbursts. The black hole flared so brightly during its activity that the team had to take precautions to protect the CCDs in their detector from radiation damage! Now the group has released the first results from their analysis.Windy DiskThe primary surprise from V404 Cyg is its winds. Many stellar-mass black holes have outflows of mass, either in the form of directed jets emitted from their centers, or in the form of high-energy winds isotropically emitted from their accretion disks. But V404

  12. Hidden Structures of Black Holes

    NASA Astrophysics Data System (ADS)

    Vercnocke, Bert

    2010-11-01

    This thesis investigates two main topics concerning black holes in extensions of general relativity inspired by string theory. First, the structure of the equations of motion underlying black hole solutions is considered, in theories of D-dimensional gravity coupled to scalars and vectors. For solutions preserving supersymmetry, the equations of motion have a dramatic simplification: they become first-order instead of the second-order equations one would expect. Recently, it was found that this is a feature some non-supersymmetric black hole solutions exhibit as well. We investigate if this holds more generally, by examining what the conditions are to have first-order equations for the scalar fields of non-supersymmetric black holes, that mimic the form of their supersymmetric counterparts. This is illustrated in examples. Second, the structure of black holes themselves is investigated. String theory has been successful in explaining the Bekenstein-Hawking entropy for (mainly supersymmetric) black holes from a microscopic perspective. However, it is not fully established what the interpretation of the corresponding 'microstates' should be in the gravitational description where the black hole picture is valid. There have been recent advances to understand the nature of black hole microstates in the gravity regime, such as the fuzzball proposal. A related idea says that black hole configurations with multiple centers are related to microstates of single-centered black holes. We report on work relating both pictures. As an aside, a relation between violations of causality for certain spacetimes (presence of closed timelike curves in the geometry) and a breakdown of unitarity in the dual conformal field theory is given.

  13. Regular phantom black holes.

    PubMed

    Bronnikov, K A; Fabris, J C

    2006-06-30

    We study self-gravitating, static, spherically symmetric phantom scalar fields with arbitrary potentials (favored by cosmological observations) and single out 16 classes of possible regular configurations with flat, de Sitter, and anti-de Sitter asymptotics. Among them are traversable wormholes, bouncing Kantowski-Sachs (KS) cosmologies, and asymptotically flat black holes (BHs). A regular BH has a Schwarzschild-like causal structure, but the singularity is replaced by a de Sitter infinity, giving a hypothetic BH explorer a chance to survive. It also looks possible that our Universe has originated in a phantom-dominated collapse in another universe, with KS expansion and isotropization after crossing the horizon. Explicit examples of regular solutions are built and discussed. Possible generalizations include k-essence type scalar fields (with a potential) and scalar-tensor gravity.

  14. Dynamically important magnetic fields near accreting supermassive black holes.

    PubMed

    Zamaninasab, M; Clausen-Brown, E; Savolainen, T; Tchekhovskoy, A

    2014-06-05

    Accreting supermassive black holes at the centres of active galaxies often produce 'jets'--collimated bipolar outflows of relativistic particles. Magnetic fields probably play a critical role in jet formation and in accretion disk physics. A dynamically important magnetic field was recently found near the Galactic Centre black hole. If this is common and if the field continues to near the black hole event horizon, disk structures will be affected, invalidating assumptions made in standard models. Here we report that jet magnetic field and accretion disk luminosity are tightly correlated over seven orders of magnitude for a sample of 76 radio-loud active galaxies. We conclude that the jet-launching regions of these radio-loud galaxies are threaded by dynamically important fields, which will affect the disk properties. These fields obstruct gas infall, compress the accretion disk vertically, slow down the disk rotation by carrying away its angular momentum in an outflow and determine the directionality of jets.

  15. More Hidden Black Hole Dangers

    NASA Technical Reports Server (NTRS)

    Wanjek, Christopher

    2003-01-01

    Black holes such as GRO J1655-40 form from collapsed stars. When stars at least eight times more massive than our Sun exhaust their fuel supply, they no longer have the energy to support their tremendous bulk. These stars explode as supernovae, blasting their outer envelopes into space. If the core is more than three times the mass of the Sun, it will collapse into a singularity, a single point of infinite density.Although light cannot escape black holes, astronomers can see black holes by virtue of the hot, glowing gas often stolen from a neighboring star that orbits these objects. From our vantage point, the light seems to flicker. The Rossi Explorer has recorded this flickering (called quasiperiodic oscillations, or QPOs) around many black holes. QPOs are produced by gas very near the innermost stable orbit the closest orbit a blob of gas can maintain before falling pell-mell into the black hole. As gas whips around the black hole at near light speed, gravity pulls the gas in one direction, then another, adding to the flickering. The QPO is related to the speed and size of this orbit and the mass of the black hole.

  16. Black Hole Grabs Starry Snack

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Poster Version

    This artist's concept shows a supermassive black hole at the center of a remote galaxy digesting the remnants of a star. NASA's Galaxy Evolution Explorer had a 'ringside' seat for this feeding frenzy, using its ultraviolet eyes to study the process from beginning to end.

    The artist's concept chronicles the star being ripped apart and swallowed by the cosmic beast over time. First, the intact sun-like star (left) ventures too close to the black hole, and its own self-gravity is overwhelmed by the black hole's gravity. The star then stretches apart (middle yellow blob) and eventually breaks into stellar crumbs, some of which swirl into the black hole (cloudy ring at right). This doomed material heats up and radiates light, including ultraviolet light, before disappearing forever into the black hole. The Galaxy Evolution Explorer was able to watch this process unfold by observing changes in ultraviolet light.

    The area around the black hole appears warped because the gravity of the black hole acts like a lens, twisting and distorting light.

  17. Gamma -bursts by primordial Black Holes

    NASA Astrophysics Data System (ADS)

    Gaina, Alex

    Gamma-burts may arise as a result of quantum generation of photons (as well as neutrinos, gravitons, electrons) by Primordial Black Holes (PBH's) of mass 5-7 x 10^14 g (Hawking: Nature, Volume 248, Issue 5443, pp. 30-31, 1974,Communications in Mathematical Physics, Volume 43, Issue 3, pp.199-220; Page:Particle emission rates from a black hole: Massless particles from an uncharged, nonrotating hole, Phys. Rev. D 13, 198, 1976,Physical Review D - Particles and Fields, 3rd Series, vol. 14, Dec. 15, 1976, p. 3260-327, Particle emission rates from a black hole. III. Charged leptons from a nonrotating hole Phys. Rev. D 16, 2402 Published 15 October 1977; Jane Mac Gibbon, Quark- and gluon-jet emission from primordial black holes. II. The emission over the black-hole lifetime Phys. Rev. D 44, 376 - Published 15 July 1991, J.H. MacGibbon & B.J. Carr,Astrophysical Journal, Part 1, vol. 371, April 20, 1991, p. 447-469 ). Another way of the Gamma-rays production by highly rotating PBH's results from the bomb-like accumulation of mass bosons on superradiative bound levels, which I have called Bose instability in Black Holes (Ternov et al.Soviet Physics Journal, Volume 21, Issue 9, pp.1200-1204 1978; Detweiler: Physical Review D (Particles and Fields), Volume 22, Issue 10, 15 November 1980, pp.2323-2326 1980; Gaina and Ternov: Soviet Astronomy Letters, vol. 12, Nov.-Dec. 1986, p. 394-396; Gaina: Soviet Astronomy Letters, Vol.15, NO.3/MAY,JUN, P. 243, 1989,Astronomical and Astrophysical Transactions, vol. 10, Issue 2, pp.111-112, 1996,Bulletin Astronomique de Belgrade, No. 153, p. 29 - 34 ). The only type of black Holes which is still undiscovered is just the primordial Black Holes type. Is this a technical problem related wuith the sensitivity of Gamma-detectors or this is rather a problem of unfinalized of the quantum mechanical treatment of the Black Holes evaporation? Is this a problem related with inexactitudes of measurements of the Hubble constant or the primordial black

  18. Black holes and Higgs stability

    SciTech Connect

    Tetradis, Nikolaos

    2016-09-20

    We study the effect of primordial black holes on the classical rate of nucleation of AdS regions within the standard electroweak vacuum. We find that the energy barrier for transitions to the new vacuum, which characterizes the exponential suppression of the nucleation rate, can be reduced significantly in the black-hole background. A precise analysis is required in order to determine whether the the existence of primordial black holes is compatible with the form of the Higgs potential at high temperature or density in the Standard Model or its extensions.

  19. Orbital resonances around black holes.

    PubMed

    Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja

    2015-02-27

    We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here.

  20. Quantum mechanics of black holes.

    PubMed

    Witten, Edward

    2012-08-03

    The popular conception of black holes reflects the behavior of the massive black holes found by astronomers and described by classical general relativity. These objects swallow up whatever comes near and emit nothing. Physicists who have tried to understand the behavior of black holes from a quantum mechanical point of view, however, have arrived at quite a different picture. The difference is analogous to the difference between thermodynamics and statistical mechanics. The thermodynamic description is a good approximation for a macroscopic system, but statistical mechanics describes what one will see if one looks more closely.

  1. Gravitational polarizability of black holes

    SciTech Connect

    Damour, Thibault; Lecian, Orchidea Maria

    2009-08-15

    The gravitational polarizability properties of black holes are compared and contrasted with their electromagnetic polarizability properties. The 'shape' or 'height' multipolar Love numbers h{sub l} of a black hole are defined and computed. They are then compared to their electromagnetic analogs h{sub l}{sup EM}. The Love numbers h{sub l} give the height of the lth multipolar 'tidal bulge' raised on the horizon of a black hole by faraway masses. We also discuss the shape of the tidal bulge raised by a test-mass m, in the limit where m gets very close to the horizon.

  2. On regular rotating black holes

    NASA Astrophysics Data System (ADS)

    Torres, R.; Fayos, F.

    2017-01-01

    Different proposals for regular rotating black hole spacetimes have appeared recently in the literature. However, a rigorous analysis and proof of the regularity of this kind of spacetimes is still lacking. In this note we analyze rotating Kerr-like black hole spacetimes and find the necessary and sufficient conditions for the regularity of all their second order scalar invariants polynomial in the Riemann tensor. We also show that the regularity is linked to a violation of the weak energy conditions around the core of the rotating black hole.

  3. Orbital Resonances Around Black Holes

    NASA Astrophysics Data System (ADS)

    Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja

    2015-02-01

    We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here.

  4. Rotating regular black hole solution

    NASA Astrophysics Data System (ADS)

    Abdujabbarov, Ahmadjon

    2016-07-01

    Based on the Newman-Janis algorithm, the Ayón-Beato-García spacetime metric [Phys. Rev. Lett. 80, 5056 (1998)] of the regular spherically symmetric, static, and charged black hole has been converted into rotational form. It is shown that the derived solution for rotating a regular black hole is regular and the critical value of the electric charge for which two horizons merge into one sufficiently decreases in the presence of the nonvanishing rotation parameter a of the black hole.

  5. A CONNECTION BETWEEN PLASMA CONDITIONS NEAR BLACK HOLE EVENT HORIZONS AND OUTFLOW PROPERTIES

    SciTech Connect

    Koljonen, K. I. I.; Russell, D. M.; Bernardini, F.; Fernández-Ontiveros, J. A.; Markoff, Sera; Russell, T. D.; Miller-Jones, J. C. A.; Curran, P. A.; Soria, R.; Van der Horst, A. J.; Casella, P.; Gandhi, P.

    2015-12-01

    Accreting black holes are responsible for producing the fastest, most powerful outflows of matter in the universe. The formation process of powerful jets close to black holes is poorly understood, and the conditions leading to jet formation are currently hotly debated. In this paper, we report an unambiguous empirical correlation between the properties of the plasma close to the black hole and the particle acceleration properties within jets launched from the central regions of accreting stellar-mass and supermassive black holes. In these sources the emission of the plasma near the black hole is characterized by a power law at X-ray energies during times when the jets are produced. We find that the photon index of this power law, which gives information on the underlying particle distribution, correlates with the characteristic break frequency in the jet spectrum, which is dependent on magnetohydrodynamical processes in the outflow. The observed range in break frequencies varies by five orders of magnitude in sources that span nine orders of magnitude in black hole mass, revealing a similarity of jet properties over a large range of black hole masses powering these jets. This correlation demonstrates that the internal properties of the jet rely most critically on the conditions of the plasma close to the black hole, rather than other parameters such as the black hole mass or spin, and will provide a benchmark that should be reproduced by the jet formation models.

  6. A Connection between Plasma Conditions near Black Hole Event Horizons and Outflow Properties

    NASA Astrophysics Data System (ADS)

    Koljonen, K. I. I.; Russell, D. M.; Fernández-Ontiveros, J. A.; Markoff, Sera; Russell, T. D.; Miller-Jones, J. C. A.; van der Horst, A. J.; Bernardini, F.; Casella, P.; Curran, P. A.; Gandhi, P.; Soria, R.

    2015-12-01

    Accreting black holes are responsible for producing the fastest, most powerful outflows of matter in the universe. The formation process of powerful jets close to black holes is poorly understood, and the conditions leading to jet formation are currently hotly debated. In this paper, we report an unambiguous empirical correlation between the properties of the plasma close to the black hole and the particle acceleration properties within jets launched from the central regions of accreting stellar-mass and supermassive black holes. In these sources the emission of the plasma near the black hole is characterized by a power law at X-ray energies during times when the jets are produced. We find that the photon index of this power law, which gives information on the underlying particle distribution, correlates with the characteristic break frequency in the jet spectrum, which is dependent on magnetohydrodynamical processes in the outflow. The observed range in break frequencies varies by five orders of magnitude in sources that span nine orders of magnitude in black hole mass, revealing a similarity of jet properties over a large range of black hole masses powering these jets. This correlation demonstrates that the internal properties of the jet rely most critically on the conditions of the plasma close to the black hole, rather than other parameters such as the black hole mass or spin, and will provide a benchmark that should be reproduced by the jet formation models.

  7. NASA's Chandra Finds Youngest Nearby Black Hole

    NASA Astrophysics Data System (ADS)

    2010-11-01

    an observed age of only about 30 years is consistent with recent theoretical work. In 2005, a theory was presented that the bright optical light of this supernova was powered by a jet from a black hole that was unable to penetrate the hydrogen envelope of the star to form a GRB. The results seen in the observations of SN 1979C fit this theory very well. Although the evidence points to a newly formed black hole in SN 1979C, another intriguing possibility is that a young, rapidly spinning neutron star with a powerful wind of high energy particles could be responsible for the X-ray emission. This would make the object in SN 1979C the youngest and brightest example of such a "pulsar wind nebula" and the youngest known neutron star. The Crab pulsar, the best-known example of a bright pulsar wind nebula, is about 950 years old. "It's very rewarding to see how the commitment of some of the most advanced telescopes in space, like Chandra, can help complete the story," said Jon Morse, head of the Astrophysics Division at NASA's Science Mission Directorate. The results will appear in the New Astronomy journal in a paper by Patnaude, Loeb, and Christine Jones of the Harvard-Smithsonian Center for Astrophysics. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge. More information, including images and other multimedia, can be found at: http://chandra.harvard.edu and http://chandra.nasa.gov

  8. Black hole meiosis

    NASA Astrophysics Data System (ADS)

    van Herck, Walter; Wyder, Thomas

    2010-04-01

    The enumeration of BPS bound states in string theory needs refinement. Studying partition functions of particles made from D-branes wrapped on algebraic Calabi-Yau 3-folds, and classifying states using split attractor flow trees, we extend the method for computing a refined BPS index, [1]. For certain D-particles, a finite number of microstates, namely polar states, exclusively realized as bound states, determine an entire partition function (elliptic genus). This underlines their crucial importance: one might call them the ‘chromosomes’ of a D-particle or a black hole. As polar states also can be affected by our refinement, previous predictions on elliptic genera are modified. This can be metaphorically interpreted as ‘crossing-over in the meiosis of a D-particle’. Our results improve on [2], provide non-trivial evidence for a strong split attractor flow tree conjecture, and thus suggest that we indeed exhaust the BPS spectrum. In the D-brane description of a bound state, the necessity for refinement results from the fact that tachyonic strings split up constituent states into ‘generic’ and ‘special’ states. These are enumerated separately by topological invariants, which turn out to be partitions of Donaldson-Thomas invariants. As modular predictions provide a check on many of our results, we have compelling evidence that our computations are correct.

  9. 'Black holes': escaping the void.

    PubMed

    Waldron, Sharn

    2013-02-01

    The 'black hole' is a metaphor for a reality in the psyche of many individuals who have experienced complex trauma in infancy and early childhood. The 'black hole' has been created by an absence of the object, the (m)other, so there is no internalized object, no (m)other in the psyche. Rather, there is a 'black hole' where the object should be, but the infant is drawn to it, trapped by it because of an intrinsic, instinctive need for a 'real object', an internalized (m)other. Without this, the infant cannot develop. It is only the presence of a real object that can generate the essential gravity necessary to draw the core of the self that is still in an undeveloped state from deep within the abyss. It is the moving towards a real object, a (m)other, that relativizes the absolute power of the black hole and begins a reformation of its essence within the psyche.

  10. The Black Hole Universe Model

    NASA Astrophysics Data System (ADS)

    Zhang, Tianxi

    2014-06-01

    The black hole universe model is a multiverse model of cosmology recently developed by the speaker. According to this new model, our universe is a fully grown extremely supermassive black hole, which originated from a hot star-like black hole with several solar masses, and gradually grew up from a supermassive black hole with million to billion solar masses to the present state with trillion-trillion solar masses by accreting ambient matter or merging with other black holes. The entire space is structured with infinite layers or universes hierarchically. The innermost three layers include the universe that we live, the inside star-like and supermassive black holes called child universes, and the outside space called mother universe. The outermost layer is infinite in mass, radius, and entropy without an edge and limits to zero for both the matter density and absolute temperature. All layers are governed by the same physics and tend to expand physically in one direction (outward or the direction of increasing entropy). The expansion of a black hole universe decreases its density and temperature but does not alter the laws of physics. The black hole universe evolves iteratively and endlessly without a beginning. When one universe expands out, a new similar one is formed from inside star-like and supermassive black holes. In each of iterations, elements are resynthesized, matter is reconfigurated, and the universe is renewed rather than a simple repeat. The black hole universe is consistent with the Mach principle, observations, and Einsteinian general relativity. It has only one postulate but is able to explain all phenomena occurred in the universe with well-developed physics. The black hole universe does not need dark energy for acceleration and an inflation epoch for flatness, and thus has a devastating impact on the big bang model. In this talk, I will present how this new cosmological model explains the various aspects of the universe, including the origin

  11. Analytical Relativity of Black Holes

    NASA Astrophysics Data System (ADS)

    Damour, Thibault

    The successful detection and analysis of gravitational wave (GW) signals from coalescing binary black holes necessitates the accurate prior knowledge of the form of the GW signals. This knowledge can be acquired through a synergy between Analytical Relativity (AR) methods and Numerical Relativity (NR) ones. We describe here the most promising AR formalism for describing the motion and radiation of coalescing binary black holes, the Effective One Body (EOB) method, and discuss its comparison with NR simulations.

  12. The Black Hole Experiment Gallery

    NASA Astrophysics Data System (ADS)

    Gould, R.; Dussault, M.; Griswold, A.; Reinfeld, E.; Steel, S.

    2008-06-01

    We report preliminary findings from the development and prototyping of the Black Hole Experiment Gallery, a NASA and NSF-funded national traveling exhibition and related educational materials on black holes. Among the innovations described are partnerships with community-based programs that enable culturally diverse youth to collaborate in exhibit development; and computer-networked technology that helps personalize visitors' exhibit experiences through the creation of a ``digital diary,'' that extends learning beyond the gallery, and that collects embedded evaluation data.

  13. "Iron-Clad" Evidence For Spinning Black Hole

    NASA Astrophysics Data System (ADS)

    2003-09-01

    competing explanations that do not require extreme gravitational effects, and provide the best look yet at the geometry of the space-time around a stellar black hole created by the death of a massive star." The orbit of a particle near a black hole depends on the curvature of space around the black hole, which also depends on how fast the black hole is spinning. A spinning black hole drags space around with it and allows atoms to orbit closer to the black hole than is possible for a non-spinning black hole. The latest Chandra data from Cygnus X-1, the first stellar-size black hole discovered, show that the gravitational effects on the signal from the iron atoms can only be due to relativistic effects, and that some of the atoms are no closer than 100 miles to the black hole. There was no evidence that the Cygnus X-1 black hole is spinning. The XMM-Newton data from the black hole, XTE J1650-500, show a very similar distribution of iron atom X-rays with one important exception. More low energy X-rays from iron atoms are observed, an indication that some X-rays are coming from deep in the gravitational well around the black hole, as close as 20 miles to the black hole event horizon. This black hole must be spinning rapidly. Chandra observations of a third stellar black hole, GX 339-4, have revealed that it is also spinning rapidly, and clouds of warm absorbing gas appear to be flowing away from the black hole at speeds of about three hundred thousand miles per hour. Such warm gas flows have been observed in the vicinity of supermassive black holes. Previous observations of some supermassive black holes by Japan's ASCA satellite, XMM-Newton and Chandra have indicated that they may also be rotating rapidly. The latest results presented by Miller indicate that the peculiar geometry of space around spinning stellar-mass black holes and supermassive black holes is remarkably similar. Stellar and supermassive black holes may be similar in other ways. Powerful jets of high

  14. Evidence for Jet Launching Close to the Black Hole in GRB 101219b—A Fermi GRB Dominated by Thermal Emission

    NASA Astrophysics Data System (ADS)

    Larsson, J.; Racusin, J. L.; Burgess, J. M.

    2015-02-01

    We present observations by the Fermi Gamma-Ray Space Telescope Gamma-Ray Burst Monitor (GBM) of the nearby (z = 0.55) GRB 101219B. This burst is a long GRB, with an associated supernova and with a blackbody (BB) component detected in the early afterglow observed by the Swift X-ray Telescope (XRT). Here we show that the prompt gamma-ray emission has a BB spectrum, making this the second such burst observed by Fermi GBM. The properties of the BB, together with the redshift and our estimate of the radiative efficiency makes it possible to calculate the absolute values of the properties of the outflow. We obtain an initial Lorentz factor Γ = 138 ± 8, a photospheric radius {{r}phot}=4.4+/- 1.9× {{10}11} cm, and a launch radius {{r}0}=2.7+/- 1.6× {{10}7} cm. The latter value is close to the black hole and suggests that the jet has a relatively unobstructed path through the star. There is no smooth connection between the BB components seen by GBM and XRT, ruling out the scenario that the late emission is due to high-latitude effects. In the interpretation that the XRT BB is prompt emission due to late central engine activity, the jet either has to be very wide or have a clumpy structure where the emission originates from a small patch. Other explanations for this component, such as emission from a cocoon surrounding the jet, are also possible.

  15. Interpreting the radio/X-ray correlation of black hole X-ray binaries based on the accretion-jet model

    NASA Astrophysics Data System (ADS)

    Xie, Fu-Guo; Yuan, Feng

    2016-03-01

    Two types of correlations between the radio and X-ray luminosities (LR and LX) have been found in black hole X-ray binaries. For some sources, they follow the `original' type of correlation which is described by a single power law. Later it was found that some other sources follow a different correlation consisting of three power-law branches, with each branch having different power-law indexes. In this work, we explain these two types of correlation under the coupled accretion-jet model. We attribute the difference between these two types of sources to the different value of viscosity parameter α. One possible reason for different α is the different configuration of magnetic field in the accretion material coming from the companion stars. For the `single power-law' sources, their α is high; so their accretion is always in the mode of advection-dominated accretion flow (ADAF) for the whole range of X-ray luminosity. For those `hybrid power-law' sources, the value of α is small so their accretion mode changes from an ADAF to a luminous hot accretion flow, and eventually to two-phase accretion as the accretion rate increases. Because the dependence of radiative efficiency on the mass accretion rate is different for these three accretion modes, different power-law indexes in the LR-LX correlation are expected. Constraints on the ratio of the mass-loss rate into the jet and the mass accretion rate in the accretion flow are obtained, which can be tested in future by radiative magnetohydrodynamic numerical simulations of jet formation.

  16. Possible evolution of supermassive black holes from FRI quasars

    NASA Astrophysics Data System (ADS)

    Kim, Matthew I.; Christian, Damian J.; Garofalo, David; D'Avanzo, Jaclyn

    2016-08-01

    We explore the question of the rapid buildup of black hole mass in the early universe employing a growing black hole mass-based determination of both jet and disc powers predicted in recent theoretical work on black hole accretion and jet formation. Despite simplified, even artificial assumptions about accretion and mergers, we identify an interesting low probability channel for the growth of one billion solar mass black holes within hundreds of millions of years of the big bang without appealing to super Eddington accretion. This result is made more compelling by the recognition of a connection between this channel and an end product involving active galaxies with FRI radio morphology but weaker jet powers in mildly sub-Eddington accretion regimes. While FRI quasars have already been shown to occupy a small region of the available parameter space for black hole feedback in the paradigm, we further suggest that the observational dearth of FRI quasars is also related to their connection to the most massive black hole growth due to both these FRIs high redshifts and relative weakness. Our results also allow us to construct the AGN (active galactic nucleus) luminosity function at high redshift, that agree with recent studies. In short, we produce a connection between the unexplained paucity of a given family of AGNs and the rapid growth of supermassive black holes, two heretofore seemingly unrelated aspects of the physics of AGNs.

  17. Evolution of Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Filloux, Charline; de Freitas Pacheco, J. A.; Durier, Fabrice; Silk, Joseph

    2010-05-01

    Cosmological simulations describing both the evolution of supermassive black holes and their host galaxies were performed by using the tree PM-SPH code GADGET-2 (Springel 2005). Physical mechanisms affecting the dynamics and the physical conditions of the gas (ionization and cooling processes, local heating by stars, injection of mechanical energy by supernovae, chemical enrichment) were introduced in the present version of the code (Filloux 2009). Black holes in a state of accretion (AGNs) also inject mechanical energy in the surrounding medium, contributing for quenching the star formation activity. In all simulations a ΛCDM cosmology was adopted (h = 0.7, ΩΛ=0.7, Ωm=0.3, Ωb=0.046 and σ8=0.9). Simulations were performed in a volume with a side of 50h-1 Mpc, starting at z = 50 and through the present time (z = 0). For low and intermediate resolution runs, the initial gas mass particles are respectively 5.35× 108 M⊙ and 3.09×108 M⊙. Black holes (BHs) are represented by collisionless particles and seeds of 100 M⊙ were introduced in density peaks at z = 15, growing either by accretion or coalescence. The accretion rate from the “disk mode” is based on a turbulent viscous thin disk model whereas in the “spherical mode” the rate is given by the Bondi-Hoyle formula. When accreting matter, jets, modeled by conical regions perpendicular to the disk plane, inject kinetic energy into the surrounding medium. Two models were tested: in the first, the injected energy rate is about 10% of the gravitational energy rate released in the accretion process while in the second, the injected energy rate is based on the Blandford & Znajek (1977) mechanism. All simulations give, at z = 0, similar black hole mass function but they overestimate slightly the BH density for masses above ~ 108 M⊙. The resulting BH density in this mass range is affected by feedback processes since they control the amount of gas available for accretion. The present simulations are not

  18. The 2015 Decay of the Black Hole X-Ray Binary V404 Cygni: Robust Disk-jet Coupling and a Sharp Transition into Quiescence

    NASA Astrophysics Data System (ADS)

    Plotkin, R. M.; Miller-Jones, J. C. A.; Gallo, E.; Jonker, P. G.; Homan, J.; Tomsick, J. A.; Kaaret, P.; Russell, D. M.; Heinz, S.; Hodges-Kluck, E. J.; Markoff, S.; Sivakoff, G. R.; Altamirano, D.; Neilsen, J.

    2017-01-01

    We present simultaneous X-ray and radio observations of the black hole X-ray binary V404 Cygni at the end of its 2015 outburst. From 2015 July 11–August 5, we monitored V404 Cygni with Chandra, Swift, and NuSTAR in the X-ray, and with the Karl G. Jansky Very Large Array and the Very Long Baseline Array in the radio, spanning a range of luminosities that were poorly covered during its previous outburst in 1989 (our 2015 campaign covers 2× {10}33≲ {L}{{X}}≲ {10}34 {erg} {{{s}}}-1). During our 2015 campaign, the X-ray spectrum evolved rapidly from a hard photon index of {{Γ }}≈ 1.6 (at {L}{{X}}≈ {10}34 {erg} {{{s}}}-1) to a softer {{Γ }}≈ 2 (at {L}{{X}}≈ 3× {10}33 {erg} {{{s}}}-1). We argue that V404 Cygni reaching {{Γ }}≈ 2 marks the beginning of the quiescent spectral state, which occurs at a factor of ≈3–4 higher X-ray luminosity than the average pre-outburst luminosity of ≈ 8× {10}32 {erg} {{{s}}}-1. V404 Cygni falls along the same radio/X-ray luminosity correlation that it followed during its previous outburst in 1989, implying a robust disk-jet coupling. We exclude the possibility that a synchrotron-cooled jet dominates the X-ray emission in quiescence, leaving synchrotron self-Compton from either a hot accretion flow or from a radiatively cooled jet as the most likely sources of X-ray radiation, and/or particle acceleration along the jet becoming less efficient in quiescence. Finally, we present the first indications of correlated radio and X-ray variability on minute timescales in quiescence, tentatively measuring the radio emission to lag the X-ray by 15+/- 4 minute, suggestive of X-ray variations propagating down a jet with a length of <3.0 au.

  19. STELLAR-MASS BLACK HOLE SPIN CONSTRAINTS FROM DISK REFLECTION AND CONTINUUM MODELING

    SciTech Connect

    Miller, J. M.; Reynolds, C. S.; Fabian, A. C.; Miniutti, G.; Gallo, L. C.

    2009-05-20

    Accretion disk reflection spectra, including broad iron emission lines, bear the imprints of the strong Doppler shifts and gravitational redshifts close to black holes. The extremity of these shifts depends on the proximity of the innermost stable circular orbit to the black hole, and that orbit is determined by the black hole spin parameter. Modeling relativistic spectral features, then, gives a means of estimating black hole spin. We report on the results of fits made to archival X-ray spectra of stellar-mass black holes and black hole candidates, selected for strong disk reflection features. Following recent work, these spectra were fit with reflection models and disk continuum emission models (where required) in which black hole spin is a free parameter. Although our results must be regarded as preliminary, we find evidence for a broad range of black hole spin parameters in our sample. The black holes with the most relativistic radio jets are found to have high spin parameters, though jets are observed in a black hole with a low spin parameter. For those sources with constrained binary system parameters, we examine the distribution of spin parameters versus black hole mass, binary mass ratio, and orbital period. We discuss the results within the context of black hole creation events, relativistic jet production, and efforts to probe the innermost relativistic regime around black holes.

  20. Supermassive Black Hole Mimics Smaller Cousins

    NASA Astrophysics Data System (ADS)

    2002-06-01

    Scientists have caught a supermassive black hole in a distant galaxy in the act of spurting energy into a jet of electrons and magnetic fields four distinct times in the past three years, a celestial take on a Yellowstone geyser. This quasar-like "active" galaxy is essentially a scaled-up model of the so-called microquasars within our Milky Way Galaxy, which are smaller black holes with as much as ten times the mass of the sun. This means that scientists can now use their close-up view of microquasars to develop working models of the most massive and powerful black holes in the universe. Artist's Conception of 3C 120. Scene from an animation of 3C 120. CREDIT: Cosmovision These results -- published in the June 6 issue of Nature -- are the fruit of a three-year monitoring campaign with the National Science Foundation's Very Long Baseline Array (VLBA), a continent-wide radio-telescope system, and NASA's Rossi X-ray Timing Explorer. "This is the first direct, observational evidence of what we had suspected: The jets in active galaxies are powered by disks of hot gas orbiting around supermassive black holes," said Alan Marscher of the Institute for Astrophysical Research at Boston University, who led this international team of astronomers. Active galaxies are distant celestial objects with exceedingly bright cores, often radiating with the brilliance of thousands of ordinary galaxies, fueled by the gravity of a central million- to billion-solar-mass black hole pulling in copious amounts of interstellar gas. Marscher and his colleagues have established the first direct observational link between a supermassive black hole and its jet. The source is an active galaxy named 3C120 about 450 million light-years from Earth. This link has been observed in microquasars, several of which are scattered across the Milky Way Galaxy, but never before in active galaxies, because the scale (distance and time) is so much greater. The jets in galaxy 3C120 are streams of particles

  1. Rethinking Black Hole Accretion Discs

    NASA Astrophysics Data System (ADS)

    Salvesen, Greg

    Accretion discs are staples of astrophysics. Tapping into the gravitational potential energy of the accreting material, these discs are highly efficient machines that produce copious radiation and extreme outflows. While interesting in their own right, accretion discs also act as tools to study black holes and directly influence the properties of the Universe. Black hole X-ray binaries are fantastic natural laboratories for studying accretion disc physics and black hole phenomena. Among many of the curious behaviors exhibited by these systems are black hole state transitions -- complicated cycles of dramatic brightening and dimming. Using X-ray observations with high temporal cadence, we show that the evolution of the accretion disc spectrum during black hole state transitions can be described by a variable disc atmospheric structure without invoking a radially truncated disc geometry. The accretion disc spectrum can be a powerful diagnostic for measuring black hole spin if the effects of the disc atmosphere on the emergent spectrum are well-understood; however, properties of the disc atmosphere are largely unconstrained. Using statistical methods, we decompose this black hole spin measurement technique and show that modest uncertainties regarding the disc atmosphere can lead to erroneous spin measurements. The vertical structure of the disc is difficult to constrain due to our ignorance of the contribution to hydrostatic balance by magnetic fields, which are fundamental to the accretion process. Observations of black hole X-ray binaries and the accretion environments near supermassive black holes provide mounting evidence for strong magnetization. Performing numerical simulations of accretion discs in the shearing box approximation, we impose a net vertical magnetic flux that allows us to effectively control the level of disc magnetization. We study how dynamo activity and the properties of turbulence driven by the magnetorotational instability depend on the

  2. Scientists Detect "Smoking Gun" of Colliding Black Holes

    NASA Astrophysics Data System (ADS)

    2002-08-01

    Images from the National Science Foundation's Very Large Array (VLA) radio telescope have uncovered compelling evidence that supermassive black holes at the hearts of large galaxies collide when their host galaxies merge. "What we have found is the smoking gun for black hole collision in merging galaxies," said David Merritt, an astrophysicist at Rutgers University in New Brunswick, New Jersey. Merritt and his colleague Ronald D. Ekers of CSIRO's Australia Telescope National Facility in Sydney, Australia, present their findings in the August 1 edition of Science Express. Jets in NGC 326 VLA image of the galaxy NGC 326, with HST image of jets inset. Click on image for larger view. CREDIT: NRAO/AUI, STScI (inset) When large galaxies merge, current models predict that their central black holes would sink toward the center of the combined galaxy and form a binary pair. "Most astronomers assume that nature finds a way to bring the black holes together, since we don't see strong evidence of binary black holes at the centers of galaxies," says Merritt. "What we have found in the VLA data is the first direct evidence that the black holes actually do coalesce." The evidence for these mergers comes from the "jets" of radio emitting particles that shoot from the cores of large galaxies. These jets are oriented parallel to the spin axis of the supermassive spinning black hole and are generated by a disk of material being pulled into it. Images taken with the VLA reveal that about 7 percent of radio emitting galaxies appear to have their jets flipped, forming what is known as an "X-type" radio source, so named because of the "X" shape of the radio lobes. "Flipped jets suggest that the black hole has suddenly been realigned," said Ekers. These features are formed, the astronomers believe, when black holes collide in a cosmic version of a demolition derby. "Black holes are so large and so massive," said Merritt, "that the only thing we can imagine that would have enough force to

  3. The Extreme Spin of the Black Hole Cygnus X-1

    NASA Technical Reports Server (NTRS)

    Gou, Lijun; McClintock, Jeffrey E.; Reid, Mark J.; Orosz, Jerome A.; Steiner, James F.; Narayan, Ramesh; Xiang, Jingen; Remillard, Ronald A.; Arnaud, Keith A.; Davis, Shane W.

    2011-01-01

    Remarkably, an astronomical black hole is completely described by the two numbers that specify its mass and its spin. Knowledge of spin is crucial for understanding how, for example, black holes produce relativistic jets. Recently, it has become possible to measure the spins of black holes by focusing on the very inner region of an accreting disk of hot gas orbiting the black hole. According to General Relativity (GR), this disk is truncated at an inner radius 1 that depends only on the mass and spin of the black hole. We measure the radius of the inner edge of this disk by fitting its continuum X-ray spectrum to a fully relativistic model. Using our measurement of this radius, we deduce that the spin of Cygnus X-1 exceeds 97% of the maximum value allowed by GR.

  4. Self-regulated growth of supermassive black holes by a dual jet-heating active galactic nucleus feedback mechanism: methods, tests and implications for cosmological simulations

    NASA Astrophysics Data System (ADS)

    Dubois, Yohan; Devriendt, Julien; Slyz, Adrianne; Teyssier, Romain

    2012-03-01

    We develop a subgrid model for the growth of supermassive black holes (BHs) and their associated active galactic nucleus (AGN) feedback in hydrodynamical cosmological simulations. This model transposes previous attempts to describe BH accretion and AGN feedback with the smoothed particle hydrodynamics (SPH) technique to the adaptive mesh refinement framework. It also furthers their development by implementing a new jet-like outflow treatment of the AGN feedback which we combine with the heating mode traditionally used in the SPH approach. Thus, our approach allows one to test the robustness of the conclusions derived from simulating the impact of self-regulated AGN feedback on galaxy formation vis-à-vis the numerical method. Assuming that BHs are created in the early stages of galaxy formation, they grow by mergers and accretion of gas at a Eddington-limited Bondi accretion rate. However this growth is regulated by AGN feedback which we model using two different modes: a quasar-heating mode when accretion rates on to the BHs are comparable to the Eddington rate, and a radio-jet mode at lower accretion rates which not only deposits energy, but also deposits mass and momentum on the grid. In other words, our feedback model deposits energy as a succession of thermal bursts and jet outflows depending on the properties of the gas surrounding the BHs. We assess the plausibility of such a model by comparing our results to observational measurements of the co-evolution of BHs and their host galaxy properties, and check their robustness with respect to numerical resolution. We show that AGN feedback must be a crucial physical ingredient for the formation of massive galaxies as it appears to be able to efficiently prevent the accumulation of and/or expel cold gas out of haloes/galaxies and significantly suppress star formation. Our model predicts that the relationship between BHs and their host galaxy mass evolves as a function of redshift, because of the vigorous accretion

  5. Violent flickering in Black Holes

    NASA Astrophysics Data System (ADS)

    2008-10-01

    Unique observations of the flickering light from the surroundings of two black holes provide new insights into the colossal energy that flows at their hearts. By mapping out how well the variations in visible light match those in X-rays on very short timescales, astronomers have shown that magnetic fields must play a crucial role in the way black holes swallow matter. Flickering black hole ESO PR Photo 36/08 Flickering black hole Like the flame from a candle, light coming from the surroundings of a black hole is not constant -- it flares, sputters and sparkles. "The rapid flickering of light from a black hole is most commonly observed at X-ray wavelengths," says Poshak Gandhi, who led the international team that reports these results. "This new study is one of only a handful to date that also explore the fast variations in visible light, and, most importantly how these fluctuations relate to those in X-rays." The observations tracked the shimmering of the black holes simultaneously using two different instruments, one on the ground and one in space. The X-ray data were taken using NASA's Rossi X-ray Timing Explorer satellite. The visible light was collected with the high speed camera ULTRACAM, a visiting instrument at ESO's Very Large Telescope (VLT), recording up to 20 images a second. ULTRACAM was developed by team members Vik Dhillon and Tom Marsh. "These are among the fastest observations of a black hole ever obtained with a large optical telescope," says Dhillon. To their surprise, astronomers discovered that the brightness fluctuations in the visible light were even more rapid than those seen in X-rays. In addition, the visible-light and X-ray variations were found not to be simultaneous, but to follow a repeated and remarkable pattern: just before an X-ray flare the visible light dims, and then surges to a bright flash for a tiny fraction of a second before rapidly decreasing again. None of this radiation emerges directly from the black hole, but from the

  6. Evaporation of Primordial Black Holes

    NASA Astrophysics Data System (ADS)

    Hawking, S. W.

    The usual explanation of the isotropy of the universe is that inflation would have smoothed out any inhomogeneities. However, if the universe was initially fractal or in a foam like state, an overall inflation would have l it in the same state. I suggest that the universe did indeed begin with a tangled web of wormholes connecting pairs of black holes but that the inflationary expansion was unstable: wormholes that are slightly smaller correspond to black holes that are hotter than the cosmological background and evaporate away. This picture is supported by calculations with Raphael Bousso of the evaporation of primordial black holes in the s-wave and large N approximations.

  7. Scrambling with matrix black holes

    NASA Astrophysics Data System (ADS)

    Brady, Lucas; Sahakian, Vatche

    2013-08-01

    If black holes are not to be dreaded sinks of information but rather fully described by unitary evolution, they must scramble in-falling data and eventually leak it through Hawking radiation. Sekino and Susskind have conjectured that black holes are fast scramblers; they generate entanglement at a remarkably efficient rate, with the characteristic time scaling logarithmically with the entropy. In this work, we focus on Matrix theory—M-theory in the light-cone frame—and directly probe the conjecture. We develop a concrete test bed for quantum gravity using the fermionic variables of Matrix theory and show that the problem becomes that of chains of qubits with an intricate network of interactions. We demonstrate that the black hole system evolves much like a Brownian quantum circuit, with strong indications that it is indeed a fast scrambler. We also analyze the Berenstein-Maldacena-Nastase model and reach the same tentative conclusion.

  8. Volume inside old black holes

    NASA Astrophysics Data System (ADS)

    Christodoulou, Marios; De Lorenzo, Tommaso

    2016-11-01

    Black holes that have nearly evaporated are often thought of as small objects, due to their tiny exterior area. However, the horizon bounds large spacelike hypersurfaces. A compelling geometric perspective on the evolution of the interior geometry was recently shown to be provided by a generally covariant definition of the volume inside a black hole using maximal surfaces. In this article, we expand on previous results and show that finding the maximal surfaces in an arbitrary spherically symmetric spacetime is equivalent to a 1 +1 geodesic problem. We then study the effect of Hawking radiation on the volume by computing the volume of maximal surfaces inside the apparent horizon of an evaporating black hole as a function of time at infinity: while the area is shrinking, the volume of these surfaces grows monotonically with advanced time, up to when the horizon has reached Planckian dimensions. The physical relevance of these results for the information paradox and the remnant scenarios are discussed.

  9. Quantum Criticality and Black Holes

    SciTech Connect

    Sachdev, Subir

    2007-08-22

    I will describe the behavior of a variety of condensed matter systems in the vicinity of zero temperature quantum phase transitions. There is a remarkable analogy between the hydrodynamics of such systems and the quantum theory of black holes. I will show how insights from this analogy have shed light on recent experiments on the cuprate high temperature superconductors. Studies of new materials and trapped ultracold atoms are yielding new quantum phases, with novel forms of quantum entanglement. Some materials are of technological importance: e.g. high temperature superconductors. Exact solutions via black hole mapping have yielded first exact results for transport coefficients in interacting many-body systems, and were valuable in determining general structure of hydrodynamics. Theory of VBS order and Nernst effect in cuprates. Tabletop 'laboratories for the entire universe': quantum mechanics of black holes, quark-gluon plasma, neutrons stars, and big-bang physics.

  10. Quantum Criticality and Black Holes

    ScienceCinema

    Sachdev, Subir [Harvard University, Cambridge, Massachusetts, United States

    2016-07-12

    I will describe the behavior of a variety of condensed matter systems in the vicinity of zero temperature quantum phase transitions. There is a remarkable analogy between the hydrodynamics of such systems and the quantum theory of black holes. I will show how insights from this analogy have shed light on recent experiments on the cuprate high temperature superconductors. Studies of new materials and trapped ultracold atoms are yielding new quantum phases, with novel forms of quantum entanglement. Some materials are of technological importance: e.g. high temperature superconductors. Exact solutions via black hole mapping have yielded first exact results for transport coefficients in interacting many-body systems, and were valuable in determining general structure of hydrodynamics. Theory of VBS order and Nernst effect in cuprates. Tabletop 'laboratories for the entire universe': quantum mechanics of black holes, quark-gluon plasma, neutrons stars, and big-bang physics.

  11. Lee-Wick black holes

    NASA Astrophysics Data System (ADS)

    Bambi, Cosimo; Modesto, Leonardo; Wang, Yixu

    2017-01-01

    We derive and study an approximate static vacuum solution generated by a point-like source in a higher derivative gravitational theory with a pair of complex conjugate ghosts. The gravitational theory is local and characterized by a high derivative operator compatible with Lee-Wick unitarity. In particular, the tree-level two-point function only shows a pair of complex conjugate poles besides the massless spin two graviton. We show that singularity-free black holes exist when the mass of the source M exceeds a critical value Mcrit. For M >Mcrit the spacetime structure is characterized by an outer event horizon and an inner Cauchy horizon, while for M =Mcrit we have an extremal black hole with vanishing Hawking temperature. The evaporation process leads to a remnant that approaches the zero-temperature extremal black hole state in an infinite amount of time.

  12. The Black Hole Information Problem

    NASA Astrophysics Data System (ADS)

    Polchinski, Joseph

    The black hole information problem has been a challenge since Hawking's original 1975 paper. It led to the discovery of AdS/CFT, which gave a partial resolution of the paradox. However, recent developments, in particular the firewall puzzle, show that there is much that we do not understand. I review the black hole, Hawking radiation, and the Page curve, and the classic form of the paradox. I discuss AdS/CFT as a partial resolution. I then discuss black hole complementarity and its limitations, leading to many proposals for different kinds of `drama.' I conclude with some recent ideas. Presented at the 2014-15 Jerusalem Winter School and the 2015 TASI.

  13. Black hole physics. Black hole lightning due to particle acceleration at subhorizon scales.

    PubMed

    Aleksić, J; Ansoldi, S; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barrio, J A; Becerra González, J; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; de Oña Wilhelmi, E; Delgado Mendez, C; Dominis Prester, D; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; García López, R J; Garczarczyk, M; Garrido Terrats, D; Gaug, M; Godinović, N; González Muñoz, A; Gozzini, S R; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Prada Moroni, P G; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Rodriguez Garcia, J; Rügamer, S; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Uellenbeck, M; Vogler, P; Zanin, R; Kadler, M; Schulz, R; Ros, E; Bach, U; Krauß, F; Wilms, J

    2014-11-28

    Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes, revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet.

  14. Black holes with vector hair

    NASA Astrophysics Data System (ADS)

    Fan, Zhong-Ying

    2016-09-01

    In this paper, we consider Einstein gravity coupled to a vector field, either minimally or non-minimally, together with a vector potential of the type V = 2{Λ}_0+1/2{m}^2{A}^2 + {γ}_4{A}^4 . For a simpler non-minimally coupled theory with Λ0 = m = γ4 = 0, we obtain both extremal and non-extremal black hole solutions that are asymptotic to Minkowski space-times. We study the global properties of the solutions and derive the first law of thermodynamics using Wald formalism. We find that the thermodynamical first law of the extremal black holes is modified by a one form associated with the vector field. In particular, due to the existence of the non-minimal coupling, the vector forms thermodynamic conjugates with the graviton mode and partly contributes to the one form modifying the first law. For a minimally coupled theory with Λ0 ≠ 0, we also obtain one class of asymptotically flat extremal black hole solutions in general dimensions. This is possible because the parameters ( m 2 , γ4) take certain values such that V = 0. In particular, we find that the vector also forms thermodynamic conjugates with the graviton mode and contributes to the corresponding first law, although the non-minimal coupling has been turned off. Thus all the extremal black hole solutions that we obtain provide highly non-trivial examples how the first law of thermodynamics can be modified by a either minimally or non-minimally coupled vector field. We also study Gauss-Bonnet gravity non-minimally coupled to a vector and obtain asymptotically flat black holes and Lifshitz black holes.

  15. FORCE-FEEDING BLACK HOLES

    SciTech Connect

    Begelman, Mitchell C.

    2012-04-10

    We propose that the growth of supermassive black holes is associated mainly with brief episodes of highly super-Eddington infall of gas ({sup h}yperaccretion{sup )}. This gas is not swallowed in real time, but forms an envelope of matter around the black hole that can be swallowed gradually, over a much longer timescale. However, only a small fraction of the black hole mass can be stored in the envelope at any one time. We argue that any infalling matter above a few percent of the hole's mass is ejected as a result of the plunge in opacity at temperatures below a few thousand degrees kelvin, corresponding to the Hayashi track. The speed of ejection of this matter, compared to the velocity dispersion {sigma} of the host galaxy's core, determines whether the ejected matter is lost forever or returns eventually to rejoin the envelope, from which it can be ultimately accreted. The threshold between matter recycling and permanent loss defines a relationship between the maximum black hole mass and {sigma} that resembles the empirical M{sub BH}-{sigma} relation.

  16. RADIO MONITORING OF THE TIDAL DISRUPTION EVENT SWIFT J164449.3+573451. I. JET ENERGETICS AND THE PRISTINE PARSEC-SCALE ENVIRONMENT OF A SUPERMASSIVE BLACK HOLE

    SciTech Connect

    Berger, E.; Zauderer, A.; Soderberg, A. M.; Sari, R.; Pooley, G. G.; Brunthaler, A.; Bietenholz, M. F.

    2012-03-20

    We present continued radio observations of the tidal disruption event Swift J164449.3+573451 extending to {delta}t Almost-Equal-To 216 days after discovery. The data were obtained with the EVLA, AMI Large Array, CARMA, the SMA, and the VLBA+Effelsberg as part of a long-term program to monitor the expansion and energy scale of the relativistic outflow, and to trace the parsec-scale environment around a previously dormant supermassive black hole (SMBH). The new observations reveal a significant change in the radio evolution starting at {delta}t Almost-Equal-To 1 month, with a brightening at all frequencies that requires an increase in the energy by about an order of magnitude, and an overall density profile around the SMBH of {rho}{proportional_to}r{sup -3/2} (0.1-1.2 pc) with a significant flattening at r Almost-Equal-To 0.4-0.6 pc. The increase in energy cannot be explained with continuous injection from an L{proportional_to}t{sup -5/3} tail, which is observed in the X-rays. Instead, we conclude that the relativistic jet was launched with a wide range of Lorentz factors, obeying E(> {Gamma}{sub j}){proportional_to}{Gamma}{sup -2.5}{sub j}. The similar ratios of duration to dynamical timescale for Sw 1644+57 and gamma-ray bursts (GRBs) suggest that this result may be applicable to GRB jets as well. The radial density profile may be indicative of Bondi accretion, with the inferred flattening at r {approx} 0.5 pc in good agreement with the Bondi radius for a {approx}few Multiplication-Sign 10{sup 6} M{sub Sun} black hole. The density at {approx}0.5 pc is about a factor of 30 times lower than inferred for the Milky Way Galactic Center, potentially due to a smaller number of mass-shedding massive stars. From our latest observations ({delta}t Almost-Equal-To 216 days) we find that the jet energy is E{sub j,iso} Almost-Equal-To 5 Multiplication-Sign 10{sup 53} erg (E{sub j} Almost-Equal-To 2.4 Multiplication-Sign 10{sup 51} erg for {theta}{sub j} = 0.1), the radius is r

  17. Two Monster Black Holes at Work

    NASA Video Gallery

    Zoom into Markarian 739, a nearby galaxy hosting two monster black holes. Using NASA's Swift and Chandra, astronomers have shown that both black holes are producing energy as gas falls into them. T...

  18. Astronomy: Intermediate-mass black hole found

    NASA Astrophysics Data System (ADS)

    Gültekin, Kayhan

    2017-02-01

    The existence of medium-sized black holes has long been debated. Such an object has now been discovered in the centre of a dense cluster of stars, potentially enhancing our understanding of all black holes. See Letter p.203

  19. Black Holes: A Selected Bibliography.

    ERIC Educational Resources Information Center

    Fraknoi, Andrew

    1991-01-01

    Offers a selected bibliography pertaining to black holes with the following categories: introductory books; introductory articles; somewhat more advanced articles; readings about Einstein's general theory of relativity; books on the death of stars; articles on the death of stars; specific articles about Supernova 1987A; relevant science fiction…

  20. From Pinholes to Black Holes

    SciTech Connect

    Fenimore, Edward E.

    2014-10-06

    Pinhole photography has made major contributions to astrophysics through the use of “coded apertures”. Coded apertures were instrumental in locating gamma-ray bursts and proving that they originate in faraway galaxies, some from the birth of black holes from the first stars that formed just after the big bang.

  1. Gravitational Collapse and Black Holes

    ERIC Educational Resources Information Center

    Ryder, Lewis

    1973-01-01

    The newest and most exotic manner in which stars die is investigated. A brief outline is presented, along with a discussion of the role supernova play, followed by a description of how the black holes originate, exist, and how they might be detected. (DF)

  2. Prisons of Light - Black Holes

    NASA Astrophysics Data System (ADS)

    Ferguson, Kitty

    1998-02-01

    Prologue; 1. A cosmic case of burnout; 2. Matters of gravity: Newton and Einstein; 3. The capture of light; 4. Tripping the theoretical fantastic; 5. Crossing the bar; 6. Contemplating an enormous nothing; 7. Evidence in the case; 8. Hearts of darkness; 9. The search goes on; 10. Passages into the labyrinth; 11. Black hole legends and far out ideas; Epilogue.

  3. Resource Letter BH-1: Black Holes.

    ERIC Educational Resources Information Center

    Detweiler, Steven

    1981-01-01

    Lists resources on black holes, including: (1) articles of historical interest; (2) books and journal articles on elementary expositions; (3) elementary and advanced textbooks; and (4) research articles on analytic structure of black holes, black hole dynamics, and astrophysical processes. (SK)

  4. Compensating Scientism through "The Black Hole."

    ERIC Educational Resources Information Center

    Roth, Lane

    The focal image of the film "The Black Hole" functions as a visual metaphor for the sacred, order, unity, and eternal time. The black hole is a symbol that unites the antinomic pairs of conscious/unconscious, water/fire, immersion/emersion, death/rebirth, and hell/heaven. The black hole is further associated with the quest for…

  5. Gravitational Lensing of STU Black Holes

    NASA Astrophysics Data System (ADS)

    Saadat, H.

    2013-12-01

    In this paper we study gravitational lensing by STU black holes. We considered extremal limit of two special cases of zero-charged and one-charged black holes, and obtain the deflection angle. We find that the black hole charge increases the deflection angle.

  6. Horndeski scalar-tensor black hole geodesics

    NASA Astrophysics Data System (ADS)

    Tretyakova, Darya; Melkoserov, Dmitry; Adyev, Timur

    2016-10-01

    We examine massive particles and null geodesics for the scalar-tensor black hole in the Horndeski-Galileon framework. Our analysis shows that first kind relativistic orbits, corresponding to circular and elliptic orbits, are absent for the black hole solution with the static scalar field. This is a highly pathological behavior contradicting to the black hole accretion and Solar System observations.

  7. Signatures of black holes at the LHC

    NASA Astrophysics Data System (ADS)

    Cavaglià, Marco; Godang, Romulus; Cremaldi, Lucien M.; Summers, Donald J.

    2007-06-01

    Signatures of black hole events at CERN's Large Hadron Collider are discussed. Event simulations are carried out with the Fortran Monte Carlo generator CATFISH. Inelasticity effects, exact field emissivities, color and charge conservation, corrections to semiclassical black hole evaporation, gravitational energy loss at formation and possibility of a black hole remnant are included in the analysis.

  8. Hyperaccreting black holes in galactic nuclei

    NASA Astrophysics Data System (ADS)

    Begelman, Mitchell C.; Volonteri, Marta

    2017-01-01

    The rate at which matter flows into a galactic nucleus during early phases of galaxy evolution can sometimes exceed the Eddington limit of the growing central black hole by several orders of magnitude. We discuss the necessary conditions for the black hole to actually accrete this matter at such a high rate, and consider the observational appearance and detectability of a hyperaccreting black hole. In order to be accreted at a hyper-Eddington rate, the infalling gas must have a sufficiently low angular momentum. Although most of the gas is accreted, a significant fraction accumulates in an optically thick envelope with luminosity ˜LEdd, probably pierced by jets of much higher power. If dot{M} > 10^3 dot{M}_Edd, the envelope spectrum resembles a blackbody with a temperature of a few thousand kelvin, but for lower (but still hyper-Eddington) accretion rates the spectrum becomes a very dilute and hard Wien spectrum. We consider the likelihood of various regimes of hyperaccretion, and discuss its possible observational signatures.

  9. Radio Detections During Two State Transitions of the Intermediate-Mass Black Hole HLX-1

    NASA Technical Reports Server (NTRS)

    Webb, Natalie; Cseh, David; Lenc, Emil; Godet, Olivier; Barret, Didier; Corbel, Stephane; Farrell, Sean; Fender, Robert; Gehrels, Neil; Heywood, Ian

    2012-01-01

    Relativistic jets are streams of plasma moving at appreciable fractions of the speed of light. They have been observed from stellar-mass black holes (approx. 3 to 20 solar masses) as well as supermassive black holes (approx.. 10(exp 6) to 10(exp 9) Solar Mass) found in the centers of most galaxies. Jets should also be produced by intermediate-mass black holes (approx. 10(exp 2) to 10(exp 5) Solar Mass), although evidence for this third class of black hole has, until recently, been weak. We report the detection of transient radio emission at the location of the intermediate-mass black hole candidate ESO 243-49 HLX-1, which is consistent with a discrete jet ejection event. These observations also allow us to refine the mass estimate of the black hole to be between approx. 9 × 10(exp 3) Solar Mass and approx. 9 × 10(exp 4) Solar Mass.

  10. Radio detections during two state transitions of the intermediate-mass black hole HLX-1.

    PubMed

    Webb, Natalie; Cseh, David; Lenc, Emil; Godet, Olivier; Barret, Didier; Corbel, Stephane; Farrell, Sean; Fender, Robert; Gehrels, Neil; Heywood, Ian

    2012-08-03

    Relativistic jets are streams of plasma moving at appreciable fractions of the speed of light. They have been observed from stellar-mass black holes (~3 to 20 solar masses, M(⊙)) as well as supermassive black holes (~10(6) to 10(9) M(⊙)) found in the centers of most galaxies. Jets should also be produced by intermediate-mass black holes (~10(2) to 10(5) M(⊙)), although evidence for this third class of black hole has, until recently, been weak. We report the detection of transient radio emission at the location of the intermediate-mass black hole candidate ESO 243-49 HLX-1, which is consistent with a discrete jet ejection event. These observations also allow us to refine the mass estimate of the black hole to be between ~9 × 10(3) M(⊙) and ~9 × 10(4) M(⊙).

  11. Black hole mimickers: Regular versus singular behavior

    SciTech Connect

    Lemos, Jose P. S.; Zaslavskii, Oleg B.

    2008-07-15

    Black hole mimickers are possible alternatives to black holes; they would look observationally almost like black holes but would have no horizon. The properties in the near-horizon region where gravity is strong can be quite different for both types of objects, but at infinity it could be difficult to discern black holes from their mimickers. To disentangle this possible confusion, we examine the near-horizon properties, and their connection with far away asymptotic properties, of some candidates to black mimickers. We study spherically symmetric uncharged or charged but nonextremal objects, as well as spherically symmetric charged extremal objects. Within the uncharged or charged but nonextremal black hole mimickers, we study nonextremal {epsilon}-wormholes on the threshold of the formation of an event horizon, of which a subclass are called black foils, and gravastars. Within the charged extremal black hole mimickers we study extremal {epsilon}-wormholes on the threshold of the formation of an event horizon, quasi-black holes, and wormholes on the basis of quasi-black holes from Bonnor stars. We elucidate whether or not the objects belonging to these two classes remain regular in the near-horizon limit. The requirement of full regularity, i.e., finite curvature and absence of naked behavior, up to an arbitrary neighborhood of the gravitational radius of the object enables one to rule out potential mimickers in most of the cases. A list ranking the best black hole mimickers up to the worst, both nonextremal and extremal, is as follows: wormholes on the basis of extremal black holes or on the basis of quasi-black holes, quasi-black holes, wormholes on the basis of nonextremal black holes (black foils), and gravastars. Since in observational astrophysics it is difficult to find extremal configurations (the best mimickers in the ranking), whereas nonextremal configurations are really bad mimickers, the task of distinguishing black holes from their mimickers seems to

  12. Black holes, cuspy atmospheres and galaxy formation.

    PubMed

    Binney, James

    2005-03-15

    In cuspy atmospheres, jets driven by supermassive black holes (BHs) offset radiative cooling. The jets fire episodically, but often enough that the cuspy atmosphere does not move very far towards a cooling catastrophe in the intervals of jet inactivity. The ability of energy released on the sub-parsec scale of the BH to balance cooling on scales of several tens of kiloparsecs arises through a combination of the temperature sensitivity of the accretion rate and the way in which the radius of jet disruption varies with ambient density. Accretion of hot gas does not significantly increase BH masses, which are determined by periods of rapid BH growth and star formation when cold gas is briefly abundant at the galactic centre. Hot gas does not accumulate in shallow potential wells. As the Universe ages, deeper wells form, and eventually hot gas accumulates. This gas soon prevents the formation of further stars, since jets powered by the BH prevent it from cooling, and it mops up most cold infalling gas before many stars can form. Thus, BHs set the upper limit to the masses of galaxies. The formation of low-mass galaxies is inhibited by a combination of photo- heating and supernova-driven galactic winds. Working in tandem, these mechanisms can probably explain the profound difference between the galaxy luminosity function and the mass function of dark haloes expected in the cold dark matter cosmology.

  13. Chandra Catches "Piranha" Black Holes

    NASA Astrophysics Data System (ADS)

    2007-07-01

    Supermassive black holes have been discovered to grow more rapidly in young galaxy clusters, according to new results from NASA's Chandra X-ray Observatory. These "fast-track" supermassive black holes can have a big influence on the galaxies and clusters that they live in. Using Chandra, scientists surveyed a sample of clusters and counted the fraction of galaxies with rapidly growing supermassive black holes, known as active galactic nuclei (or AGN). The data show, for the first time, that younger, more distant galaxy clusters contained far more AGN than older, nearby ones. Galaxy clusters are some of the largest structures in the Universe, consisting of many individual galaxies, a few of which contain AGN. Earlier in the history of the universe, these galaxies contained a lot more gas for star formation and black hole growth than galaxies in clusters do today. This fuel allows the young cluster black holes to grow much more rapidly than their counterparts in nearby clusters. Illustration of Active Galactic Nucleus Illustration of Active Galactic Nucleus "The black holes in these early clusters are like piranha in a very well-fed aquarium," said Jason Eastman of Ohio State University (OSU) and first author of this study. "It's not that they beat out each other for food, rather there was so much that all of the piranha were able to really thrive and grow quickly." The team used Chandra to determine the fraction of AGN in four different galaxy clusters at large distances, when the Universe was about 58% of its current age. Then they compared this value to the fraction found in more nearby clusters, those about 82% of the Universe's current age. The result was the more distant clusters contained about 20 times more AGN than the less distant sample. AGN outside clusters are also more common when the Universe is younger, but only by factors of two or three over the same age span. "It's been predicted that there would be fast-track black holes in clusters, but we never

  14. Black Holes, Thermodynamics, and Quantum Theory

    NASA Astrophysics Data System (ADS)

    Wald, Robert

    2017-01-01

    A black hole is a region of ``no escape'' that remains behind after a body has undergone complete gravitational collapse. It is truly remarkable that (i) black holes obey the ordinary laws of thermodynamics, (ii) the entropy of a black hole is given by a simple formula involving geometrical properties of its event horizon, and (iii) quantum theory plays an essential role in the thermodynamic properties of black holes. In this talk, I will review some of the key developments related to these properties of black holes, which fascinated me as a graduate student and continue to fascinate me now.

  15. Noncritical superstring-black hole transition

    SciTech Connect

    Parnachev, Andrei; Sahakyan, David A.

    2006-04-15

    An interesting case of string/black hole transition occurs in two-dimensional noncritical string theory dressed with a compact CFT. In these models the high energy densities of states of perturbative strings and black holes have the same leading behavior when the Hawking temperature of the black hole is equal to the Hagedorn temperature of perturbative strings. We compare the first subleading terms in the black hole and closed string entropies in this setting and argue that the entropy interpolates between these expressions as the energy is varied. We compute the subleading correction to the black hole entropy for a specific simple model.

  16. Dramatic Outburst Reveals Nearest Black Hole

    NASA Astrophysics Data System (ADS)

    2000-01-01

    Scientists have discovered the closest black hole yet, a mere 1,600 light years from Earth. Its discovery was heralded by four of the most dramatic rapid X-ray intensity changes ever seen from one star. Astronomers from the Massachusetts Institute of Technology (MIT) and the National Science Foundation's National Radio Astronomy Observatory (NRAO) announced their findings at the American Astronomical Society's meeting in Atlanta. The black hole in the constellation Sagittarius, along with a normal star dubbed V4641 Sgr, form a violent system that briefly flooded part of our Milky Way Galaxy with X-rays and ejected subatomic particles moving at nearly the speed of light one day last September. At the peak of its X-ray output, V4641 Sgr was the brightest X-ray emitter in the sky. Astronomers call this type of system an X-ray nova because it suddenly becomes a bright source of X-rays, but this object shows characteristics never seen in an X-ray nova. "V4641 Sgr turns on and off so fast that it seems to represent a new subclass of X-ray novae," said Donald A. Smith, postdoctoral associate in MIT's Center for Space Research. Smith worked on data from this object with MIT principal research scientist Ronald Remillard and NRAO astronomer Robert Hjellming. "In X-rays, the intensity rose by a factor of more than 1,000 in seven hours, then dropped by a factor of 100 in two hours," Remillard said. The radio emission was seen as an image of an expanding "jet" of particles shooting out from the binary system. After reaching a maximum, the radio intensity dropped by a factor of nearly 40 within two days. "Radio telescopes give us a quick glimpse of something moving at a fantastically high velocity," Hjellming said. Black holes harbor enormous gravitational force that can literally rip the gas away from a nearby star. This transfer of gas is visible in many forms of radiation. Both orbiting X-ray telescopes and ground-based radio and optical telescopes saw the outburst of V4641

  17. Tracing black hole mergers through radio lobe morphology.

    PubMed

    Merritt, David; Ekers, R D

    2002-08-23

    Binary supermassive black holes are produced by galactic mergers as the black holes from the two galaxies fall to the center of the merged system and form a bound pair. The two black holes will eventually coalesce in an enormous burst of gravitational radiation. Here we show that the orientation of a black hole's spin axis would change dramatically even in a minor merger, leading to a sudden flip in the direction of any associated jet. We identify the winged or X-type radio sources with galaxies in which this has occurred. The inferred coalescence rate is similar to the overall galaxy merger rate, implying that of the order of one merger event per year could be detected by gravitational wave interferometers.

  18. WARPED DISK AROUND A BRIGHT BLACK HOLE (ARTWORK)

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This diagram shows the geometry of a warped disk of dust surrounding a suspected black hole in the active galaxy NGC 6251. The diagram is based on NASA Hubble Space Telescope images of the disk which reveal that only one side reflects light emitted from a suspected black hole, hence the disk is warped. Such a warp could be due to gravitational perturbations in the galaxy's nucleus that keep the disk from being perfectly flat, or from precession of the rotation axis of the black hole relative to the rotation axis of the galaxy. Perpendicular to the disk is a jet of high-energy particles blasted into space along the black hole's spin axis. Illustration: James Gitlin (Space Telescope Science Institute)

  19. Strong gravitational lensing by Kiselev black hole

    NASA Astrophysics Data System (ADS)

    Younas, Azka; Jamil, Mubasher; Bahamonde, Sebastian; Hussain, Saqib

    2015-10-01

    We investigate the gravitational lensing scenario due to Schwarzschild-like black hole surrounded by quintessence (Kiselev black hole). We work for the special case of Kiselev black hole where we take the state parameter wq=-2/3 . For the detailed derivation and analysis of the bending angle involved in the deflection of light, we discuss three special cases of Kiselev black hole: nonextreme, extreme, and naked singularity. We also calculate the approximate bending angle and compare it with the exact bending angle. We found the relation of bending angles in the decreasing order as: naked singularity, extreme Kiselev black hole, nonextreme Kiselev black hole, and Schwarzschild black hole. In the weak field approximation, we compute the position and total magnification of relativistic images as well.

  20. Quantum information erasure inside black holes

    NASA Astrophysics Data System (ADS)

    Lowe, David A.; Thorlacius, Larus

    2015-12-01

    An effective field theory for infalling observers in the vicinity of a quasi-static black hole is given in terms of a freely falling lattice discretization. The lattice model successfully reproduces the thermal spectrum of outgoing Hawking radiation, as was shown by Corley and Jacobson, but can also be used to model observations made by a typical low-energy observer who enters the black hole in free fall at a prescribed time. The explicit short distance cutoff ensures that, from the viewpoint of the infalling observer, any quantum information that entered the black hole more than a scrambling time earlier has been erased by the black hole singularity. This property, combined with the requirement that outside observers need at least of order the scrambling time to extract quantum information from the black hole, ensures that a typical infalling observer does not encounter drama upon crossing the black hole horizon in a theory where black hole information is preserved for asymptotic observers.

  1. Black holes in magnetic monopoles

    NASA Technical Reports Server (NTRS)

    Lee, Kimyeong; Nair, V. P.; Weinberg, Erick J.

    1991-01-01

    We study magnetically charged classical solutions of a spontaneously broken gauge theory interacting with gravity. We show that nonsingular monopole solutions exist only if the Higgs field vacuum expectation value v is less than or equal to a critical value v sub cr, which is of the order of the Planck mass. In the limiting case, the monopole becomes a black hole, with the region outside the horizon described by the critical Reissner-Nordstrom solution. For v less than v sub cr, we find additional solutions which are singular at f = 0, but which have this singularity hidden within a horizon. These have nontrivial matter fields outside the horizon, and may be interpreted as small black holes lying within a magnetic monopole. The nature of these solutions as a function of v and of the total mass M and their relation to the Reissner-Nordstrom solutions is discussed.

  2. Close supermassive binary black holes.

    PubMed

    Gaskell, C Martin

    2010-01-07

    It has been proposed that when the peaks of the broad emission lines in active galactic nuclei (AGNs) are significantly blueshifted or redshifted from the systemic velocity of the host galaxy, this could be a consequence of orbital motion of a supermassive black-hole binary (SMBB). The AGN J1536+0441 ( = SDSS J153636.22+044127.0) has recently been proposed as an example of this phenomenon. It is proposed here instead that J1536+0441 is an example of line emission from a disk. If this is correct, the lack of clear optical spectral evidence for close SMBBs is significant, and argues either that the merging of close SMBBs is much faster than has generally been hitherto thought, or if the approach is slow, that when the separation of the binary is comparable to the size of the torus and broad-line region, the feeding of the black holes is disrupted.

  3. Complexity, action, and black holes

    DOE PAGES

    Brown, Adam R.; Roberts, Daniel A.; Susskind, Leonard; ...

    2016-04-18

    In an earlier paper "Complexity Equals Action" we conjectured that the quantum computational complexity of a holographic state is given by the classical action of a region in the bulk (the `Wheeler-DeWitt' patch). We provide calculations for the results quoted in that paper, explain how it fits into a broader (tensor) network of ideas, and elaborate on the hypothesis that black holes are the fastest computers in nature.

  4. Complexity, action, and black holes

    NASA Astrophysics Data System (ADS)

    Brown, Adam R.; Roberts, Daniel A.; Susskind, Leonard; Swingle, Brian; Zhao, Ying

    2016-04-01

    Our earlier paper "Complexity Equals Action" conjectured that the quantum computational complexity of a holographic state is given by the classical action of a region in the bulk (the "Wheeler-DeWitt" patch). We provide calculations for the results quoted in that paper, explain how it fits into a broader (tensor) network of ideas, and elaborate on the hypothesis that black holes are the fastest computers in nature.

  5. Soft Hair on Black Holes.

    PubMed

    Hawking, Stephen W; Perry, Malcolm J; Strominger, Andrew

    2016-06-10

    It has recently been shown that Bondi-van der Burg-Metzner-Sachs supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft (i.e., zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This Letter gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the horizon area in Planck units.

  6. Soft Hair on Black Holes

    NASA Astrophysics Data System (ADS)

    Hawking, Stephen W.; Perry, Malcolm J.; Strominger, Andrew

    2016-06-01

    It has recently been shown that Bondi-van der Burg-Metzner-Sachs supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft (i.e., zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This Letter gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the horizon area in Planck units.

  7. Constraints on black hole remnants

    SciTech Connect

    Giddings, S.B. )

    1994-01-15

    One possible fate of information lost to black holes is its preservation in black hole remnants. It is argued that a type of effective field theory describes such remnants (generically referred to as informons). The general structure of such a theory is investigated and the infinite pair production problem is revisited. A toy model for remnants clarifies some of the basic issues; in particular, infinite remnant production is not suppressed simply by the large internal volumes as proposed in cornucopion scenarios. Criteria for avoiding infinite production are stated in terms of couplings in the effective theory. Such instabilities remain a problem barring what would be described in that theory as a strong coupling conspiracy. The relation to Euclidean calculations of cornucopion production is sketched, and potential flaws in that analysis are outlined. However, it is quite plausible that pair production of ordinary black holes (e.g., Reissner-Noerdstrom or others) is suppressed due to strong effective couplings. It also remains an open possibility that a microsopic dynamics can be found yielding an appropriate strongly coupled effective theory of neutral informons without infinite pair production.

  8. Accretion disks around black holes

    NASA Technical Reports Server (NTRS)

    Abramowicz, M. A.

    1994-01-01

    The physics of accretion flow very close to a black hole is dominated by several general relativistic effects. It cannot be described by the standard Shakura Sunyaev model or by its relativistic version developed by Novikov and Thome. The most important of these effects is a dynamical mass loss from the inner edge of the disk (Roche lobe overflow). The relativistic Roche lobe overflow induces a strong advective cooling, which is sufficient to stabilize local, axially symmetric thermal and viscous modes. It also stabilizes the non-axially-symmetric global modes discovered by Papaloizou and Pringle. The Roche lobe overflow, however, destabilizes sufficiently self-gravitating accretion disks with respect to a catastrophic runaway of mass due to minute changes of the gravitational field induced by the changes in the mass and angular momentum of the central black hole. One of the two acoustic modes may become trapped near the inner edge of the disk. All these effects, absent in the standard model, have dramatic implications for time-dependent behavior of the accretion disks around black holes.

  9. Black holes on all scales: similarities and differences

    NASA Astrophysics Data System (ADS)

    Done, Chris

    2015-04-01

    I will review what we know about astrophysical black holes, from the stellar mass back holes formed from the death of massive stars, to the supermassive black holes in galaxy centres. Where material falls onto a black hole of any size, the enourmous gravitational energy released transforms these darkest objects in the Universe into the brightest. The luminous accretion flow lights up the regions of intensely curved spacetime, and its spectrum and variabilty carry the imprint of strong gravity as well as the geometry and dynamics of the emitting material. I will show how the stellar mass black holes form a homogeneous set, and how their large changes in mass accretion rate on easily observable timescales mean that they form a a template for how the spectrum and variability of the accretion flow, and its associated jet, change with mass accretion rate. They ubiquitously show a dramatic switch in both spectral, variability and jet properties as the mass accretion rate changes, probably associated with a change from a hot, geometrically thick flow to a cool, geometrically thin disc. Since the geometry and dynamics of the disc are well understood, these spectra give a clean test of Einstin's gravity in the strong field limit, with clear evidence for the existance of a last stable circular orbit. The hot flows are less well understood, but it is possible that the characteristic timescale for variabilty seen in these data is from Lens-Thirring (vertical) precession of the flow around the black hole. Scaling these models of a changing accretion flow up to the supermassive black holes can give an explanation for the multiple different types of unobscured AGN. However, as well as similarities, there are also some differences in the properties of the spectra, variability and particularly in the jet. A small subset of the most massive black holes have highly relativistic jets, with relativisitically emitting out to GeV or TeV energies. I show that the statistics of these jets

  10. Black Hole Spectral States and Physical Connections

    NASA Technical Reports Server (NTRS)

    Tomsick, John A.

    2006-01-01

    The dramatic changes seen in the X-ray spectral and timing properties of accreting black hole candidates (BHCs) provide important clues about the accretion and jet formation processes that occur in these systems. Dividing the different source behaviors into spectral states provides a framework for studying BHCs. To date, there have been three main classification schemes with Luminosity-based, Component-based, or Transition-based criteria. The canonical, Luminosity-based criteria and physical models that are based on this concept do not provide clear explanations for several phenomena, including hysteresis of spectral states and the presence of jets. I discuss the re-definitions of states, focusing on an application of the Component-based states to more than 400 RXTE observations of the recurrent BHC 4U 1630^17. We compare the X-ray properties for the recent 2002-2004 outburst to those of an earlier (1998) outburst, during which radio jets were observed. The results suggest a connection between hysteresis of states and major jet ejections, and it is possible that both of these are related to the evolution of the inner radius of the optically thick accretion disk.

  11. Black Hole Spectral States and Physical Connections

    NASA Technical Reports Server (NTRS)

    Tomsick, John A.

    2005-01-01

    The dramatic changes seen in the X-ray spectral and timing properties of accreting black hole candidates (BHCs) provide important clues about the accretion and jet formation processes that occur in these systems. Dividing the different source behaviors into spectral states provides a framework for studying BHCs. To date, there have been three main classification schemes with Luminosity-based, Component-based, or Transition-based criteria. The canonical, Luminosity-based criteria and physical models that are based on this concept do not provide clear explanations for several phenomena, including hysteresis of spectral states and the presence of jets. I discuss the re-definitions of states, focusing on an application of the Component-based states to more than 400 RXTE observations of the recurrent BHC 4U 1630-47. We compare the X-ray properties for the recent 2002-2004 outburst to those of an earlier (1998) outburst, during which radio jets were observed. The results suggest a connection between hysteresis of states and major jet ejections, and it is possible that both of these are related to the evolution of the inner radius of the optically thick accretion disk.

  12. Black Holes, Worm Holes, and Future Space Propulsion

    NASA Technical Reports Server (NTRS)

    Barret, Chris

    2000-01-01

    NASA has begun examining the technologies needed for an Interstellar Mission. In 1998, a NASA Interstellar Mission Workshop was held at the California Institute of Technology to examine the technologies required. Since then, a spectrum of research efforts to support such a mission has been underway, including many advanced and futuristic space propulsion concepts which are being explored. The study of black holes and wormholes may provide some of the breakthrough physics needed to travel to the stars. The first black hole, CYGXI, was discovered in 1972 in the constellation Cygnus X-1. In 1993, a black hole was found in the center of our Milky Way Galaxy. In 1994, the black hole GRO J1655-40 was discovered by the NASA Marshall Space Flight center using the Gamma Ray Observatory. Today, we believe we have found evidence to support the existence of 19 black holes, but our universe may contain several thousands. This paper discusses the dead star states - - both stable and unstable, white dwarfs, neutron stars, pulsars, quasars, the basic features and types of black holes: nonspinning, nonspinning with charge, spinning, and Hawking's mini black holes. The search for black holes, gravitational waves, and Laser Interferometer Gravitational Wave Observatory (LIGO) are reviewed. Finally, concepts of black hole powered space vehicles and wormhole concepts for rapid interstellar travel are discussed in relation to the NASA Interstellar Mission.

  13. DARK JETS IN SOLAR CORONAL HOLES

    SciTech Connect

    Young, Peter R.

    2015-03-10

    A new solar feature termed a dark jet is identified from observations of an extended solar coronal hole that was continuously monitored for over 44 hr by the Extreme Ultraviolet Imaging Spectrometer on board the Hinode spacecraft in 2011 February 8–10 as part of Hinode Operation Plan No. 177 (HOP 177). Line of sight (LOS) velocity maps derived from the coronal Fe xii λ195.12 emission line, formed at 1.5 MK, revealed a number of large-scale, jet-like structures that showed significant blueshifts. The structures had either weak or no intensity signal in 193 Å filter images from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory, suggesting that the jets are essentially invisible to imaging instruments. The dark jets are rooted in bright points and occur both within the coronal hole and at the quiet Sun–coronal hole boundary. They exhibit a wide range of shapes, from narrow columns to fan-shaped structures, and sometimes multiple jets are seen close together. A detailed study of one dark jet showed LOS speeds increasing along the jet axis from 52 to 107 km s{sup −1} and a temperature of 1.2–1.3 MK. The low intensity of the jet was due either to a small filling factor of 2% or to a curtain-like morphology. From the HOP 177 sample, dark jets are as common as regular coronal hole jets, but their low intensity suggests a mass flux around two orders of magnitude lower.

  14. A Black Hole in Our Galactic Center

    ERIC Educational Resources Information Center

    Ruiz, Michael J.

    2008-01-01

    An introductory approach to black holes is presented along with astronomical observational data pertaining to the presence of a supermassive black hole at the center of our galaxy. Concepts of conservation of energy and Kepler's third law are employed so students can apply formulas from their physics class to determine the mass of the black hole…

  15. Ghost Remains After Black Hole Eruption

    NASA Astrophysics Data System (ADS)

    2009-05-01

    NASA's Chandra X-ray Observatory has found a cosmic "ghost" lurking around a distant supermassive black hole. This is the first detection of such a high-energy apparition, and scientists think it is evidence of a huge eruption produced by the black hole. This discovery presents astronomers with a valuable opportunity to observe phenomena that occurred when the Universe was very young. The X-ray ghost, so-called because a diffuse X-ray source has remained after other radiation from the outburst has died away, is in the Chandra Deep Field-North, one of the deepest X-ray images ever taken. The source, a.k.a. HDF 130, is over 10 billion light years away and existed at a time 3 billion years after the Big Bang, when galaxies and black holes were forming at a high rate. "We'd seen this fuzzy object a few years ago, but didn't realize until now that we were seeing a ghost", said Andy Fabian of the Cambridge University in the United Kingdom. "It's not out there to haunt us, rather it's telling us something - in this case what was happening in this galaxy billions of year ago." Fabian and colleagues think the X-ray glow from HDF 130 is evidence for a powerful outburst from its central black hole in the form of jets of energetic particles traveling at almost the speed of light. When the eruption was ongoing, it produced prodigious amounts of radio and X-radiation, but after several million years, the radio signal faded from view as the electrons radiated away their energy. HDF 130 Chandra X-ray Image of HDF 130 However, less energetic electrons can still produce X-rays by interacting with the pervasive sea of photons remaining from the Big Bang - the cosmic background radiation. Collisions between these electrons and the background photons can impart enough energy to the photons to boost them into the X-ray energy band. This process produces an extended X-ray source that lasts for another 30 million years or so. "This ghost tells us about the black hole's eruption long after

  16. Black Hole Caught Zapping Galaxy into Existence?

    NASA Astrophysics Data System (ADS)

    2009-11-01

    equivalent to about 350 Suns per year, one hundred times more than rates for typical galaxies in the local Universe. Earlier observations had shown that the companion galaxy is, in fact, under fire: the quasar is spewing a jet of highly energetic particles towards its companion, accompanied by a stream of fast-moving gas. The injection of matter and energy into the galaxy indicates that the quasar itself might be inducing the formation of stars and thereby creating its own host galaxy; in such a scenario, galaxies would have evolved from clouds of gas hit by the energetic jets emerging from quasars. "The two objects are bound to merge in the future: the quasar is moving at a speed of only a few tens of thousands of km/h with respect to the companion galaxy and their separation is only about 22 000 light-years," says Elbaz. "Although the quasar is still 'naked', it will eventually be 'dressed' when it merges with its star-rich companion. It will then finally reside inside a host galaxy like all other quasars." Hence, the team have identified black hole jets as a possible driver of galaxy formation, which may also represent the long-sought missing link to understanding why the mass of black holes is larger in galaxies that contain more stars [3]. "A natural extension of our work is to search for similar objects in other systems," says Jahnke. Future instruments, such as the Atacama Large Millimeter/submillimeter Array, the European Extremely Large Telescope and the NASA/ESA/CSA James Webb Space Telescope will be able to search for such objects at even larger distances from us, probing the connection between black holes and the formation of galaxies in the more distant Universe. Notes [1] Supermassive black holes are found in the cores of most large galaxies; unlike the inactive and starving one sitting at the centre of the Milky Way, a fraction of them are said to be active, as they eat up enormous amounts of material. These frantic actions produce a copious release of energy

  17. Stationary black holes: large D analysis

    NASA Astrophysics Data System (ADS)

    Suzuki, Ryotaku; Tanabe, Kentaro

    2015-09-01

    We consider the effective theory of large D stationary black holes. By solving the Einstein equations with a cosmological constant using the 1 /D expansion in near zone of the black hole we obtain the effective equation for the stationary black hole. The effective equation describes the Myers-Perry black hole, bumpy black holes and, possibly, the black ring solution as its solutions. In this effective theory the black hole is represented as an embedded membrane in the background, e.g., Minkowski or Anti-de Sitter spacetime and its mean curvature is given by the surface gravity redshifted by the background gravitational field and the local Lorentz boost. The local Lorentz boost property of the effective equation is observed also in the metric itself. In fact we show that the leading order metric of the Einstein equation in the 1 /D expansion is generically regarded as a Lorentz boosted Schwarzschild black hole. We apply this Lorentz boost property of the stationary black hole solution to solve perturbation equations. As a result we obtain an analytic formula for quasinormal modes of the singly rotating Myers-Perry black hole in the 1 /D expansion.

  18. Hawking temperature of constant curvature black holes

    SciTech Connect

    Cai Ronggen; Myung, Yun Soo

    2011-05-15

    The constant curvature (CC) black holes are higher dimensional generalizations of Banados-Teitelboim-Zanelli black holes. It is known that these black holes have the unusual topology of M{sub D-1}xS{sup 1}, where D is the spacetime dimension and M{sub D-1} stands for a conformal Minkowski spacetime in D-1 dimensions. The unusual topology and time-dependence for the exterior of these black holes cause some difficulties to derive their thermodynamic quantities. In this work, by using a globally embedding approach, we obtain the Hawking temperature of the CC black holes. We find that the Hawking temperature takes the same form when using both the static and global coordinates. Also, it is identical to the Gibbons-Hawking temperature of the boundary de Sitter spaces of these CC black holes.

  19. Binary black hole merger dynamics and waveforms

    NASA Technical Reports Server (NTRS)

    Baker, John G.; Centrella, Joan; Choi, Dae-II; Koppitz, Michael; vanMeter, James

    2006-01-01

    We apply recently developed techniques for simulations of moving black holes to study dynamics and radiation generation in the last few orbits and merger of a binary black hole system. Our analysis produces a consistent picture from the gravitational wave forms and dynamical black hole trajectories for a set of simulations with black holes beginning on circular-orbit trajectories at a variety of initial separations. We find profound agreement at the level of 1% among the simulations for the last orbit, merger and ringdown, resulting in a final black hole with spin parameter a/m = 0.69. Consequently, we are confident that this part of our waveform result accurately represents the predictions from Einstein's General Relativity for the final burst of gravitational radiation resulting from the merger of an astrophysical system of equal-mass non-spinning black holes. We also find good agreement at a level of roughly 10% for the radiation generated in the preceding few orbits.

  20. Black holes in modified gravity (MOG)

    NASA Astrophysics Data System (ADS)

    Moffat, J. W.

    2015-04-01

    The field equations for scalar-tensor-vector gravity (STVG) or modified gravity (MOG) have a static, spherically symmetric black hole solution determined by the mass with two horizons. The strength of the gravitational constant is where is a parameter. A regular singularity-free MOG solution is derived using a nonlinear field dynamics for the repulsive gravitational field component and a reasonable physical energy-momentum tensor. The Kruskal-Szekeres completion of the MOG black hole solution is obtained. The Kerr-MOG black hole solution is determined by the mass , the parameter and the spin angular momentum . The equations of motion and the stability condition of a test particle orbiting the MOG black hole are derived, and the radius of the black hole photosphere and the shadows cast by the Schwarzschild-MOG and Kerr-MOG black holes are calculated. A traversable wormhole solution is constructed with a throat stabilized by the repulsive component of the gravitational field.

  1. What if a black hole devours too much?

    NASA Astrophysics Data System (ADS)

    Liu, Jifeng

    2016-01-01

    The formation of relativistic jets by an accreting compact object is one of the fundamental mysteries of astrophysics. While the theory is poorly understood, observations of relativistic jets from systems known as microquasars have led to a well-established phenomenology. Relativistic jets are not expected from sources with soft or supersoft X-ray spectra, although two such systems are known to produce relatively low-velocity bipolar outflows. Here we report optical spectra of an ultraluminous supersoft X-ray source (ULS) in the nearby galaxy M81 (M81 ULS-1) showing blueshifted broad Hα emission lines, characteristic of baryonic jets with relativistic speeds. The time variable jets have projected velocities ~17 per cent of the speed of light, and seem similar to those in the prototype microquasar SS 433. Such relativistic jets are not expected to be launched from white dwarfs, but an origin from a black hole or neutron star in M81 ULS-1 is hard to reconcile with its constant soft X-rays. The completely unexpected presence of relativistic jets in a ULS challenges the canonical theories for jet formation, but can be explained by a long speculated super-critically accreting black hole with optically thick outflows.

  2. Techniques for Binary Black Hole Simulations

    NASA Technical Reports Server (NTRS)

    Baker, John G.

    2006-01-01

    Recent advances in techniques for numerical simulation of black hole systems have enabled dramatic progress in astrophysical applications. Our approach to these simulations, which includes new gauge conditions for moving punctures, AMR, and specific tools for analyzing black hole simulations, has been applied to a variety of black hole configurations, typically resulting in simulations lasting several orbits. I will discuss these techniques, what we've learned in applications, and outline some areas for further development.

  3. Quantum radiation of general nonstationary black holes

    NASA Astrophysics Data System (ADS)

    Hua, Jia-Chen; Huang, Yong-Chang

    2009-02-01

    Quantum radiation of general nonstationary black holes is investigated by using the method of generalized tortoise-coordinate transformation (GTT). It is shown in general that the temperature and the shape of the event horizon of this kind of black holes depend on time and angle. Further, we find that the chemical potential in the thermal-radiation spectrum is equal to the highest energy of the negative-energy state of particles in nonthermal radiation for general nonstationary black holes.

  4. Corrected Entropy of BTZ Black Holes

    NASA Astrophysics Data System (ADS)

    Farahani, Hoda; Sadeghi, Jafar; Saadat, Hassan

    2012-12-01

    In this paper, corrected entropy of a class of BTZ black holes, include charge and rotation, studied. We obtain corrected Bekenstein-Hawking entropy and find that effect of charge viewed at order A -2, and effect of rotation viewed at order A -6, therefore Q and J don't have contribution in corrected entropy lower than the second order. We also write the first law of black hole thermodynamics for the case of charged rotating BTZ black hole.

  5. Test fields cannot destroy extremal black holes

    NASA Astrophysics Data System (ADS)

    Natário, José; Queimada, Leonel; Vicente, Rodrigo

    2016-09-01

    We prove that (possibly charged) test fields satisfying the null energy condition at the event horizon cannot overspin/overcharge extremal Kerr-Newman or Kerr-Newman-anti de Sitter black holes, that is, the weak cosmic censorship conjecture cannot be violated in the test field approximation. The argument relies on black hole thermodynamics (without assuming cosmic censorship), and does not depend on the precise nature of the fields. We also discuss generalizations of this result to other extremal black holes.

  6. Black holes and the chocolate cake concept.

    PubMed

    Allen, A

    1994-10-01

    The force of black holes in the universe is compared with the intense gravitational fields that we must navigate in our personal galaxy. Stressed by the many demands of home, work, and community, we are in danger of slipping into the black holes present in every aspect of our lives. The Chocolate Cake Concept is offered as a means of avoiding the black holes by breaking down barriers that influence our attitudes.

  7. Black holes in the milky way galaxy.

    PubMed

    Filippenko, A V

    1999-08-31

    Extremely strong observational evidence has recently been found for the presence of black holes orbiting a few relatively normal stars in our Milky Way Galaxy and also at the centers of some galaxies. The former generally have masses of 4-16 times the mass of the sun, whereas the latter are "supermassive black holes" with millions to billions of solar masses. The evidence for a supermassive black hole in the center of our galaxy is especially strong.

  8. Spinning black holes as particle accelerators.

    PubMed

    Jacobson, Ted; Sotiriou, Thomas P

    2010-01-15

    It has recently been pointed out that particles falling freely from rest at infinity outside a Kerr black hole can in principle collide with an arbitrarily high center of mass energy in the limiting case of maximal black hole spin. Here we aim to elucidate the mechanism for this fascinating result, and to point out its practical limitations, which imply that ultraenergetic collisions cannot occur near black holes in nature.

  9. Boson shells harboring charged black holes

    SciTech Connect

    Kleihaus, Burkhard; Kunz, Jutta; Laemmerzahl, Claus; List, Meike

    2010-11-15

    We consider boson shells in scalar electrodynamics coupled to Einstein gravity. The interior of the shells can be empty space, or harbor a black hole or a naked singularity. We analyze the properties of these types of solutions and determine their domains of existence. We investigate the energy conditions and present mass formulae for the composite black hole-boson shell systems. We demonstrate that these types of solutions violate black hole uniqueness.

  10. GOODS Missing Black Hole Report: Hundreds Found!

    NASA Astrophysics Data System (ADS)

    2007-10-01

    Astronomers have unmasked hundreds of black holes hiding deep inside dusty galaxies billions of light-years away Normal Galaxies Normal Galaxies The massive, growing black holes, discovered by NASA's Spitzer and Chandra space telescopes, represent a large fraction of a long-sought missing population. Their discovery implies there are hundreds of millions of additional black holes growing in our young universe, more than doubling the total amount known at that distance. "Active, supermassive black holes are everywhere in the early universe," said Mark Dickinson of the National Optical Astronomy Observatory in Tucson, Ariz. "We had seen the tip of the iceberg before in our search for these objects. Now, we can see the iceberg itself." Dickinson is a co-author of two new papers appearing in the Nov. 10 issue of the Astrophysical Journal. Emanuele Daddi of the Commissariat a l'Energie Atomique in France led the research. The findings are also the first direct evidence that most, if not all, massive galaxies in the distant universe spend their youths building monstrous black holes at their cores. For decades, large populations of active black holes have been considered missing. These highly energetic structures, also called quasars, consist of a dusty, doughnut-shaped cloud that surrounds and feeds a growing supermassive black hole. They give off a lot of X-rays that can be detected as a general glow in space, but sometimes the quasars themselves can't be seen because dust and gas blocks their X-rays from our point of view. "We knew from other studies from about 30 years ago that there must be more quasars in the universe, but we didn't know where to find them until now," said Daddi. Daddi and his team initially set out to study 1,000 dusty, massive galaxies that are busy making stars, and were thought to lack quasars. The galaxies are about the same mass as our own spiral Milky Way galaxy, but irregular in shape. At 9 to 11 billion light-years away, they exist at a

  11. Low-mass black holes as the remnants of primordial black hole formation.

    PubMed

    Greene, Jenny E

    2012-01-01

    Bridging the gap between the approximately ten solar mass 'stellar mass' black holes and the 'supermassive' black holes of millions to billions of solar masses are the elusive 'intermediate-mass' black holes. Their discovery is key to understanding whether supermassive black holes can grow from stellar-mass black holes or whether a more exotic process accelerated their growth soon after the Big Bang. Currently, tentative evidence suggests that the progenitors of supermassive black holes were formed as ∼10(4)-10(5) M(⊙) black holes via the direct collapse of gas. Ongoing searches for intermediate-mass black holes at galaxy centres will help shed light on this formation mechanism.

  12. The Black Hole Formation Probability

    NASA Astrophysics Data System (ADS)

    Clausen, Drew R.; Piro, Anthony; Ott, Christian D.

    2015-01-01

    A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. Using the observed BH mass distribution from Galactic X-ray binaries, we investigate the probability that a star will make a BH as a function of its ZAMS mass. Although the shape of the black hole formation probability function is poorly constrained by current measurements, we believe that this framework is an important new step toward better understanding BH formation. We also consider some of the implications of this probability distribution, from its impact on the chemical enrichment from massive stars, to its connection with the structure of the core at the time of collapse, to the birth kicks that black holes receive. A probabilistic description of BH formation will be a useful input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment.

  13. Bohr-like black holes

    SciTech Connect

    Corda, Christian

    2015-03-10

    The idea that black holes (BHs) result in highly excited states representing both the “hydrogen atom” and the “quasi-thermal emission” in quantum gravity is today an intuitive but general conviction. In this paper it will be shown that such an intuitive picture is more than a picture. In fact, we will discuss a model of quantum BH somewhat similar to the historical semi-classical model of the structure of a hydrogen atom introduced by Bohr in 1913. The model is completely consistent with existing results in the literature, starting from the celebrated result of Bekenstein on the area quantization.

  14. Black Hole Researchers in Schools

    NASA Astrophysics Data System (ADS)

    Doran, Rosa

    2016-07-01

    "Black Holes in my School" is a research project that aims to explore the impact of engaging students in real research experiences while learning new skills and topics addressed in the regular school curriculum. The project introduces teachers to innovative tools for science teaching, explore student centered methodologies such as inquiry based learning and provides a setting where students take the role of an astrophysicist researching the field of compact stellar mass objects in binary systems. Students will study already existing data and use the Faulkes Telescopes to acquire new data. In this presentation the main aim is to present the framework being built and the results achieved so far.

  15. Schwarzschild black holes can wear scalar wigs.

    PubMed

    Barranco, Juan; Bernal, Argelia; Degollado, Juan Carlos; Diez-Tejedor, Alberto; Megevand, Miguel; Alcubierre, Miguel; Núñez, Darío; Sarbach, Olivier

    2012-08-24

    We study the evolution of a massive scalar field surrounding a Schwarzschild black hole and find configurations that can survive for arbitrarily long times, provided the black hole or the scalar field mass is small enough. In particular, both ultralight scalar field dark matter around supermassive black holes and axionlike scalar fields around primordial black holes can survive for cosmological times. Moreover, these results are quite generic in the sense that fairly arbitrary initial data evolve, at late times, as a combination of those long-lived configurations.

  16. Particle accelerators inside spinning black holes.

    PubMed

    Lake, Kayll

    2010-05-28

    On the basis of the Kerr metric as a model for a spinning black hole accreting test particles from rest at infinity, I show that the center-of-mass energy for a pair of colliding particles is generically divergent at the inner horizon. This shows not only that classical black holes are internally unstable, but also that Planck-scale physics is a characteristic feature within black holes at scales much larger that the Planck length. The novel feature of the divergence discussed here is that the phenomenon is present only for black holes with rotation, and in this sense it is distinct from the well-known Cauchy horizon instability.

  17. On black hole spectroscopy via adiabatic invariance

    NASA Astrophysics Data System (ADS)

    Jiang, Qing-Quan; Han, Yan

    2012-12-01

    In this Letter, we obtain the black hole spectroscopy by combining the black hole property of adiabaticity and the oscillating velocity of the black hole horizon. This velocity is obtained in the tunneling framework. In particular, we declare, if requiring canonical invariance, the adiabatic invariant quantity should be of the covariant form Iadia = ∮pi dqi. Using it, the horizon area of a Schwarzschild black hole is quantized independently of the choice of coordinates, with an equally spaced spectroscopy always given by ΔA = 8 π lp2 in the Schwarzschild and Painlevé coordinates.

  18. Black Holes versus Supersymmetry at the LHC

    NASA Astrophysics Data System (ADS)

    Roy, Arunava; Cavaglia, Marco

    2007-11-01

    Supersymmetry and extra dimensions are the two most promising candidates for new physics at the TeV scale. Supersymmetric particles or extra-dimensional effects could soon be observed at the Large Hadron Collider. In this paper we assess the distinguishability of supersymmetry and black hole events at the LHC. Black hole events are simulated with the CATFISH black hole generator. Supersymmetry simulations use a combination of PYTHIA and ISAJET, the latter providing the mass spectrum. Our analysis shows that supersymmetry and black hole events at the Large Hadron Collider can be easily discriminated.

  19. Do black holes really evaporate thermally

    NASA Astrophysics Data System (ADS)

    Tipler, F. J.

    1980-09-01

    The Raychaudhuri equation is used to analyze the effect of the Hawking radiation back reaction upon a black-hole event horizon. It is found that if the effective stress-energy tensor of the Hawking radiation has negative energy density as expected, then an evaporating black hole initially a solar mass in size must disappear in less than a second. This implies that either the evaporation process, if it occurs at all, must be quite different from what is commonly supposed, or else black-hole event horizons - and hence black holes - do not exist.

  20. Black hole collapse and democratic models

    NASA Astrophysics Data System (ADS)

    Jansen, Aron; Magán, Javier M.

    2016-11-01

    We study the evolution of black hole entropy and temperature in collapse scenarios in asymptotically anti-de Sitter spacetime, finding three generic lessons. First, entropy evolution is extensive. Second, at large times, entropy and temperature ring with twice the frequency of the lowest quasinormal mode. Third, the entropy oscillations saturate black hole area theorems in general relativity. The first two features are characteristic of entanglement dynamics in "democratic" models. Solely based on general relativity and the Bekenstein-Hawking entropy formula, our results point to democratic models as microscopic theories of black holes. The third feature can be taken as a prediction for microscopic models of black hole physics.

  1. Semiclassical geometry of charged black holes

    SciTech Connect

    Frolov, Andrei V.; Kristjansson, Kristjan R.; Thorlacius, Larus

    2005-07-15

    At the classical level, two-dimensional dilaton gravity coupled to an abelian gauge field has charged black hole solutions, which have much in common with four-dimensional Reissner-Nordstroem black holes, including multiple asymptotic regions, timelike curvature singularities, and Cauchy horizons. The black hole spacetime is, however, significantly modified by quantum effects, which can be systematically studied in this two-dimensional context. In particular, the back-reaction on the geometry due to pair-creation of charged fermions destabilizes the inner horizon and replaces it with a spacelike curvature singularity. The semiclassical geometry has the same global topology as an electrically neutral black hole.

  2. Micro black holes and the democratic transition

    NASA Astrophysics Data System (ADS)

    Dvali, Gia; Pujolàs, Oriol

    2009-03-01

    Unitarity implies that the evaporation of microscopic quasiclassical black holes cannot be universal in different particle species. This creates a puzzle, since it conflicts with the thermal nature of quasiclassical black holes, according to which all of the species should see the same horizon and be produced with the same Hawking temperatures. We resolve this puzzle by showing that for the microscopic black holes, on top of the usual quantum evaporation time, there is a new time scale which characterizes a purely classical process during which the black hole loses the ability to differentiate among the species and becomes democratic. We demonstrate this phenomenon in a well-understood framework of large extra dimensions, with a number of parallel branes. An initially nondemocratic black hole is the one localized on one of the branes, with its high-dimensional Schwarzschild radius being much shorter than the interbrane distance. Such a black hole seemingly cannot evaporate into the species localized on the other branes that are beyond its reach. We demonstrate that in reality the system evolves classically in time, in such a way that the black hole accretes the neighboring branes. The end result is a completely democratic static configuration, in which all of the branes share the same black hole and all of the species are produced with the same Hawking temperature. Thus, just like their macroscopic counterparts, the microscopic black holes are universal bridges to the hidden sector physics.

  3. Black holes and local dark matter

    NASA Technical Reports Server (NTRS)

    Hegyi, D. J.; Kolb, E. W.; Olive, K. A.

    1986-01-01

    Two independent constraints are placed on the amount of dark matter in black holes contained in the galactic disk. First, gas accretion by black holes leads to X-ray emission which cannot exceed the observed soft X-ray background. Second, metals produced in stellar processes that lead to black hole formation cannot exceed the observed disk metal abundance. Based on these constraints, it appears unlikely that the missing disk mass could be contained in black holes. A consequence of this conclusion is that at least two different types of dark matter are needed to solve the various missing mass problems.

  4. Rotating black holes and Coriolis effect

    NASA Astrophysics Data System (ADS)

    Chou, Chia-Jui; Wu, Xiaoning; Yang, Yi; Yuan, Pei-Hung

    2016-10-01

    In this work, we consider the fluid/gravity correspondence for general rotating black holes. By using the suitable boundary condition in near horizon limit, we study the correspondence between gravitational perturbation and fluid equation. We find that the dual fluid equation for rotating black holes contains a Coriolis force term, which is closely related to the angular velocity of the black hole horizon. This can be seen as a dual effect for the frame-dragging effect of rotating black hole under the holographic picture.

  5. Gamma ray astronomy and black hole astrophysics

    NASA Technical Reports Server (NTRS)

    Liang, Edison P.

    1990-01-01

    The study of soft gamma emissions from black-hole candidates is identified as an important element in understanding black-hole phenomena ranging from stellar-mass black holes to AGNs. The spectra of Cyg X-1 and observations of the Galactic Center are emphasized, since thermal origins and MeV gamma-ray bumps are evident and suggest a thermal-pair cloud picture. MeV gamma-ray observations are suggested for studying black hole astrophysics such as the theorized escaping pair wind, the anticorrelation between the MeV gamma bump and the soft continuum, and the relationship between source compactness and temperature.

  6. NASA Observatory Confirms Black Hole Limits

    NASA Astrophysics Data System (ADS)

    2005-02-01

    The very largest black holes reach a certain point and then grow no more, according to the best survey to date of black holes made with NASA's Chandra X-ray Observatory. Scientists have also discovered many previously hidden black holes that are well below their weight limit. These new results corroborate recent theoretical work about how black holes and galaxies grow. The biggest black holes, those with at least 100 million times the mass of the Sun, ate voraciously during the early Universe. Nearly all of them ran out of 'food' billions of years ago and went onto a forced starvation diet. Focus on Black Holes in the Chandra Deep Field North Focus on Black Holes in the Chandra Deep Field North On the other hand, black holes between about 10 and 100 million solar masses followed a more controlled eating plan. Because they took smaller portions of their meals of gas and dust, they continue growing today. "Our data show that some supermassive black holes seem to binge, while others prefer to graze", said Amy Barger of the University of Wisconsin in Madison and the University of Hawaii, lead author of the paper describing the results in the latest issue of The Astronomical Journal (Feb 2005). "We now understand better than ever before how supermassive black holes grow." One revelation is that there is a strong connection between the growth of black holes and the birth of stars. Previously, astronomers had done careful studies of the birthrate of stars in galaxies, but didn't know as much about the black holes at their centers. DSS Optical Image of Lockman Hole DSS Optical Image of Lockman Hole "These galaxies lose material into their central black holes at the same time that they make their stars," said Barger. "So whatever mechanism governs star formation in galaxies also governs black hole growth." Astronomers have made an accurate census of both the biggest, active black holes in the distance, and the relatively smaller, calmer ones closer by. Now, for the first

  7. Observational Features of Equatorial Coronal Hole Jets

    DTIC Science & Technology

    2010-02-10

    It is usually assumed that a jet is the result of magnetic re- connection happening in the solar corona between the large- scale open unipolar...plasma jets in the solar corona , Solar Phys., 190: 167-184,1999. Cirtain, J. W., Golub, L., Lundquist, L., Ballegooijen van, A., Savcheva, A., Shimojo, M...T.: The magnetic structure of Hα Macruspicules in solar corona holes, The Astrophysical J., 605: 511-520, 2004. Yokoyama, T. and Shibata, K

  8. Primordial black holes in globular clusters

    NASA Technical Reports Server (NTRS)

    Sigurdsson, Steinn; Hernquist, Lars

    1993-01-01

    It has recently been recognized that significant numbers of medium-mass back holes (of order 10 solar masses) should form in globular clusters during the early stages of their evolution. Here we explore the dynamical and observational consequences of the presence of such a primordial black-hole population in a globular cluster. The holes initially segregate to the cluster cores, where they form binary and multiple black-hole systems. The subsequent dynamical evolution of the black-hole population ejects most of the holes on a relatively short timescale: a typical cluster will retain between zero and four black holes in its core, and possibly a few black holes in its halo. The presence of binary, triple, and quadruple black-hole systems in cluster cores will disrupt main-sequence and giant stellar binaries; this may account for the observed anomalies in the distribution of binaries in globular clusters. Furthermore, tidal interactions between a multiple black-hole system and a red giant star can remove much of the red giant's stellar envelope, which may explain the puzzling absence of larger red giants in the cores of some very dense clusters.

  9. Entanglement Entropy of Black Holes

    NASA Astrophysics Data System (ADS)

    Solodukhin, Sergey N.

    2011-12-01

    The entanglement entropy is a fundamental quantity, which characterizes the correlations between sub-systems in a larger quantum-mechanical system. For two sub-systems separated by a surface the entanglement entropy is proportional to the area of the surface and depends on the UV cutoff, which regulates the short-distance correlations. The geometrical nature of entanglement-entropy calculation is particularly intriguing when applied to black holes when the entangling surface is the black-hole horizon. I review a variety of aspects of this calculation: the useful mathematical tools such as the geometry of spaces with conical singularities and the heat kernel method, the UV divergences in the entropy and their renormalization, the logarithmic terms in the entanglement entropy in four and six dimensions and their relation to the conformal anomalies. The focus in the review is on the systematic use of the conical singularity method. The relations to other known approaches such as ’t Hooft’s brick-wall model and the Euclidean path integral in the optical metric are discussed in detail. The puzzling behavior of the entanglement entropy due to fields, which non-minimally couple to gravity, is emphasized. The holographic description of the entanglement entropy of the blackhole horizon is illustrated on the two- and four-dimensional examples. Finally, I examine the possibility to interpret the Bekenstein-Hawking entropy entirely as the entanglement entropy.

  10. Superluminality, black holes and EFT

    NASA Astrophysics Data System (ADS)

    Goon, Garrett; Hinterbichler, Kurt

    2017-02-01

    Under the assumption that a UV theory does not display superluminal behavior, we ask what constraints on superluminality are satisfied in the effective field theory (EFT). We study two examples of effective theories: quantum electrodynamics (QED) coupled to gravity after the electron is integrated out, and the flat-space galileon. The first is realized in nature, the second is more speculative, but they both exhibit apparent superluminality around non-trivial backgrounds. In the QED case, we attempt, and fail, to find backgrounds for which the superluminal signal advance can be made larger than the putative resolving power of the EFT. In contrast, in the galileon case it is easy to find such backgrounds, indicating that if the UV completion of the galileon is (sub)luminal, quantum corrections must become important at distance scales of order the Vainshtein radius of the background configuration, much larger than the naive EFT strong coupling distance scale. Such corrections would be reminiscent of the non-perturbative Schwarzschild scale quantum effects that are expected to resolve the black hole information problem. Finally, a byproduct of our analysis is a calculation of how perturbative quantum effects alter charged Reissner-Nordstrom black holes.

  11. Codimension-2 Brane Black Holes

    NASA Astrophysics Data System (ADS)

    Zamorano, Nelson; Arias, Cesar; Ordenes, Ariel; Guzman, Francisco

    2012-03-01

    We analyze the geometry associated to a six dimensional solution of the Einstein's equations. It describes a Schwarzschild de-Sitter black hole on a 3-brane, surrounded by a two dimensional compact bulk. A four dimensional effective cosmological constant and a Planck mass are matched to their six dimensional counterpart. Deviation from Newton's law are computed in both of the solutions found. To learn about the geometry of the bulk, we study the geodesics in this sector. At least, in our opinion, there are some features of these solutions that makes worth to pursue this analysis. The singularity associated to the warped bulk is controlled by the mass M of the black hole. It vanishes if we set M=0. In the same context, it makes an interesting problem to study the Gregory-Laflamme instability in this context [1]. Another feature is the rugby ball type of geometry exhibited by these solutions [2]. They end up in two conical singularities at its respective poles. The branes are located precisely at the poles. Besides, a Wick's rotation generates a connection between different solutions. [4pt] [1] R. Gregory and R. Laflamme, Phys. Rev Lett., 70,2837 (1993)[0pt] [2] S. M. Carroll and M. M. Guica, arXiv:hep-th/0302067

  12. Spacetime and orbits of bumpy black holes

    SciTech Connect

    Vigeland, Sarah J.; Hughes, Scott A.

    2010-01-15

    Our Universe contains a great number of extremely compact and massive objects which are generally accepted to be black holes. Precise observations of orbital motion near candidate black holes have the potential to determine if they have the spacetime structure that general relativity demands. As a means of formulating measurements to test the black hole nature of these objects, Collins and Hughes introduced ''bumpy black holes'': objects that are almost, but not quite, general relativity's black holes. The spacetimes of these objects have multipoles that deviate slightly from the black hole solution, reducing to black holes when the deviation is zero. In this paper, we extend this work in two ways. First, we show how to introduce bumps which are smoother and lead to better behaved orbits than those in the original presentation. Second, we show how to make bumpy Kerr black holes--objects which reduce to the Kerr solution when the deviation goes to zero. This greatly extends the astrophysical applicability of bumpy black holes. Using Hamilton-Jacobi techniques, we show how a spacetime's bumps are imprinted on orbital frequencies, and thus can be determined by measurements which coherently track the orbital phase of a small orbiting body. We find that in the weak field, orbits of bumpy black holes are modified exactly as expected from a Newtonian analysis of a body with a prescribed multipolar structure, reproducing well-known results from the celestial mechanics literature. The impact of bumps on strong-field orbits is many times greater than would be predicted from a Newtonian analysis, suggesting that this framework will allow observations to set robust limits on the extent to which a spacetime's multipoles deviate from the black hole expectation.

  13. How Supermassive Black Hole Feedback Might Work

    NASA Astrophysics Data System (ADS)

    Donahue, Megan

    2017-01-01

    How black holes regulate their own growth and the growth of their host galaxy is an unsolved problem in galaxy evolution. The problem is particularly acute in the centers of clusters of galaxies, where the largest and most massive galaxies in the universe are found. That is, coincidentally, also where the interaction between the black hole and the surrounding gas is the easiest to study because the gas is sufficiently hot and dense to emit X-rays. The massive central galaxies of clusters of galaxies (BCGs) exhibit striking patterns in their relationships between star formation, radio AGN activity, and the thermodynamic state of the hot, X-ray emitting intracluster gas (ICM) surrounding the galaxies. The AGN jets excavate giant, kpc-scale cavities in the hot gas, in principle, supplying enough heat to the ICM to replace energy lost to radiative cooling. Simulations suggest (by elimination) that AGN feedback must be required to explain the luminosity and colors of these galaxies, but cosmological simulations still struggle with modeling how AGN feedback works in detail. In clusters of galaxies with active AGN and star-forming BCGs, the AGN somehow regulates the gaseous atmosphere to be marginally critical, with a ratio of the cooling time to the free fall time of ~ 5-20. This behavior is also seen in elliptical galaxies, where the feedback is mostly coming from stars. I will discuss the observations that motivated this model. The precipitation model in BCGs is a class of models known as "preventative" feedback, regulated by jets in BCGs. Further, the complex behaviour seen in recent idealized simulations seem to follow emergent patterns predicted by this model, while reproducing the scatter and the time scales inferred from the observations. The link between the thermal instabilities and the depth of the gravitational potential may explain scaling laws such as the black hole mass-velocity dispersion relation, the galaxy mass-metallicity relation and the baryonic

  14. Black Hole Interior in Quantum Gravity.

    PubMed

    Nomura, Yasunori; Sanches, Fabio; Weinberg, Sean J

    2015-05-22

    We discuss the interior of a black hole in quantum gravity, in which black holes form and evaporate unitarily. The interior spacetime appears in the sense of complementarity because of special features revealed by the microscopic degrees of freedom when viewed from a semiclassical standpoint. The relation between quantum mechanics and the equivalence principle is subtle, but they are still consistent.

  15. How to Create Black Holes on Earth

    ERIC Educational Resources Information Center

    Bleicher, Marcus

    2007-01-01

    We present a short overview on the ideas of large extra dimensions and their implications for the possible production of micro black holes in the next generation particle accelerator at CERN (Geneva, Switzerland) from this year on. In fact, the possibility of black hole production on Earth is currently one of the most exciting predictions for the…

  16. Physics near Rapidly Spinning Black Holes

    NASA Astrophysics Data System (ADS)

    Gralla, Samuel; Lupsasca, Alexandru; Hughes, Scott; Porfyriadis, Achilleas; Strominger, Andrew; Warburton, Niels

    2016-03-01

    The near-horizon region of a near-extreme Kerr black hole possesses additional emergent symmetries and can be thought of as a spacetime in its own right. I will discuss the dynamics of particles and fields in this region, the constraints imposed by symmetry, and observational consequences for astrophysical black holes.

  17. Effective Potential in Noncommutative BTZ Black Hole

    NASA Astrophysics Data System (ADS)

    Sadeghi, Jafar; Shajiee, Vahid Reza

    2016-02-01

    In this paper, we investigated the noncommutative rotating BTZ black hole and showed that such a space-time is not maximally symmetric. We calculated effective potential for the massive and the massless test particle by geodesic equations, also we showed effect of non-commutativity on the minimum mass of BTZ black hole.

  18. Gravitational Waves From Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    di Girolamo, Tristano

    2016-10-01

    In this talk, I will present the first direct detections of gravitational waves from binary stellar-mass black hole mergers during the first observing run of the two detectors of the Advanced Laser Interferometer Gravitational-wave Observatory, which opened the field of gravitational-wave astronomy, and then discuss prospects for observing gravitational waves from supermassive black holes with future detectors.

  19. Slender Galaxy with Robust Black Hole

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This plot of data from NASA's Spitzer Space Telescope indicates that a flat, spiral galaxy called NGC 3621 has a feeding, supermassive black hole lurking within it -- a surprise considering that astronomers thought this particular class of super-thin galaxies lacked big black holes.

    The data were captured by Spitzer's infrared spectrograph, an instrument that cracks infrared light open to reveal the signatures of elements. In this case, the data, or spectrum, for NGC 3621, shows the signature of highly ionized neon -- a sure sign of an active, supermassive black hole. Only a black hole that is actively consuming gas and stars has enough energy to ionize neon to this state. The other features in this plot are polycyclic aromatic hydrocarbons and chlorine, produced in the gas surrounding stars.

    The results challenge current theories, which hold that supermassive black holes require the bulbous central bulges that poke out from many spiral galaxies to form and grow. NGC 3621 is the second disk galaxy without any bulge found to harbor a supermassive black hole; the first, found in 2003, is NGC 4395. Astronomers have also used Spitzer to find six other mega black holes in thin spirals with only minimal bulges. Together, the findings indicate that, for a galaxy, being plump in the middle is not a necessary condition for growing a rotund black hole.

  20. Pregalactic black holes - A new constraint

    NASA Technical Reports Server (NTRS)

    Barrow, J. D.; Silk, J.

    1979-01-01

    Pregalactic black holes accrete matter in the early universe and produce copious amounts of X radiation. By using observations of the background radiation in the X and gamma wavebands, a strong constraint is imposed upon their possible abundance. If pregalactic black holes are actually present, several outstanding problems of cosmogony can be resolved with typical pregalactic black hole masses of 100 solar masses. Significantly more massive holes cannot constitute an appreciable mass fraction of the universe and are limited by a specific mass-density bound.

  1. Nucleosynthesis in the neighborhood of a black hole

    NASA Technical Reports Server (NTRS)

    Chakrabarti, Sandip K.

    1986-01-01

    The preliminary results from simulations of nucleosynthesis inside a thick accretion disk around a black hole are discussed as a function of the accretion rate, the viscosity parameter, and the mass of the black hole. Results for the Bondi accretion case are also presented. Taking the case of a 10-solar mass and a 10 to the 6th-solar mass central Schwarzschild hole, detailed evolution of a representative element of matter as it accretes into the hole is presented in the case when the initial abundance (at the outer edge of the disk) is the same as the solar abundance. It is suggested that such studies may eventually shed light on the composition of the outgoing jets observed in the active galaxies and SS433.

  2. Shadow of noncommutative geometry inspired black hole

    SciTech Connect

    Wei, Shao-Wen; Cheng, Peng; Zhong, Yi; Zhou, Xiang-Nan E-mail: pcheng14@lzu.edu.cn E-mail: zhouxn10@lzu.edu.cn

    2015-08-01

    In this paper, the shadow casted by the rotating black hole inspired by noncommutative geometry is investigated. In addition to the dimensionless spin parameter a/M{sub 0} with M{sub 0} black hole mass and inclination angle i, the dimensionless noncommutative parameter √θ/M{sub 0} is also found to affect the shape of the black hole shadow. The result shows that the size of the shadow slightly decreases with the parameter √θ/M{sub 0}, while the distortion increases with it. Compared to the Kerr black hole, the parameter √θ/M{sub 0} increases the deformation of the shadow. This may offer a way to distinguish noncommutative geometry inspired black hole from Kerr one via astronomical instruments in the near future.

  3. Testing conformal gravity with astrophysical black holes

    NASA Astrophysics Data System (ADS)

    Bambi, Cosimo; Cao, Zheng; Modesto, Leonardo

    2017-03-01

    Weyl conformal symmetry can solve the problem the spacetime singularities present in Einstein's gravity. In a recent paper, two of us have found a singularity-free rotating black hole solution in conformal gravity. In addition to the mass M and the spin angular momentum J of the black hole, the new solution has a new parameter, L , which here we consider to be proportional to the black hole mass. Since the solution is conformally equivalent to the Kerr metric, photon trajectories are unchanged, while the structure of an accretion disk around a black hole is affected by the value of the parameter L . In this paper, we show that x-ray data of astrophysical black holes require L /M <1.2 .

  4. Binary Black Holes from Dense Star Clusters

    NASA Astrophysics Data System (ADS)

    Rodriguez, Carl

    2017-01-01

    The recent detections of gravitational waves from merging binary black holes have the potential to revolutionize our understanding of compact object astrophysics. But to fully utilize this new window into the universe, we must compare these observations to detailed models of binary black hole formation throughout cosmic time. In this talk, I will review our current understanding of cluster dynamics, describing how binary black holes can be formed through gravitational interactions in dense stellar environments, such as globular clusters and galactic nuclei. I will review the properties and merger rates of binary black holes from the dynamical formation channel. Finally, I will describe how the spins of a binary black hole are determined by its formation history, and how we can use this to discriminate between dynamically-formed binaries and those formed from isolated evolution in galactic fields.

  5. Renormalized vacuum polarization of rotating black holes

    NASA Astrophysics Data System (ADS)

    Ferreira, Hugo R. C.

    2015-04-01

    Quantum field theory on rotating black hole spacetimes is plagued with technical difficulties. Here, we describe a general method to renormalize and compute the vacuum polarization of a quantum field in the Hartle-Hawking state on rotating black holes. We exemplify the technique with a massive scalar field on the warped AdS3 black hole solution to topologically massive gravity, a deformation of (2 + 1)-dimensional Einstein gravity. We use a "quasi-Euclidean" technique, which generalizes the Euclidean techniques used for static spacetimes, and we subtract the divergences by matching to a sum over mode solutions on Minkowski spacetime. This allows us, for the first time, to have a general method to compute the renormalized vacuum polarization, for a given quantum state, on a rotating black hole, such as the physically relevant case of the Kerr black hole in four dimensions.

  6. Modeling Flows Around Merging Black Hole Binaries

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2008-01-01

    Coalescing massive black hole binaries are produced by the merger of galaxies. The final stages of the black hole coalescence produce strong gravitational radiation that can be detected by the space-borne LISA. In cases in which the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We have taken a first step towards this problem by mapping the flow of pressureless matter in the dynamic, 3-D general relativistic spacetime around the merging black holes. We report on the results of these initial simulations and discuss their likely importance for future hydrodynamical simulations.

  7. Thermodynamics in Black-Hole Correspondence

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Zhang, Jia-Ju

    2013-09-01

    The area law of Bekenstein-Hawking entropy of the black hole suggests that the black hole should have a lower-dimensional holographic description. It has been found recently that a large class of rotating and charged black holes could be holographically described a two-dimensional (2D) conformal field theory (CFT). We show that the universal information of the dual CFT, including the central charges and the temperatures, is fully encoded in the thermodynamics laws of both outer and inner horizons. These laws, characterizing how the black hole responds under the perturbation, allows us to read different dual pictures with respect to different kinds of perturbations. The remarkable effectiveness of this thermodynamics method suggest that the inner horizon could play a key role in the study of holographic description of the black hole.

  8. Central charge for the Schwarzschild black hole

    NASA Astrophysics Data System (ADS)

    Ropotenko, K.

    2016-12-01

    Proceeding in exactly the same way as in the derivation of the temperature of a dual CFT for the extremal black hole in the Kerr/CFT correspondence, it is found that the temperature of a chiral, dual CFT for the Schwarzschild black hole is T = 1/2π. Comparing Cardy’s formula with the Bekenstein-Hawking entropy and using T, it is found that the central charge for the Schwarzschild black hole is of the form c = 12Jin, where Jin is the intrinsic angular momentum of the black hole, Jin = A/8πG. It is shown that the central charge for any four-dimensional (4D) extremal black hole is of the same form. The possible universality of this form is briefly discussed.

  9. Black hole thermodynamics in MOdified Gravity (MOG)

    NASA Astrophysics Data System (ADS)

    Mureika, Jonas R.; Moffat, John W.; Faizal, Mir

    2016-06-01

    We analyze the thermodynamical properties of black holes in a modified theory of gravity, which was initially proposed to obtain correct dynamics of galaxies and galaxy clusters without dark matter. The thermodynamics of non-rotating and rotating black hole solutions resembles similar solutions in Einstein-Maxwell theory with the electric charge being replaced by a new mass dependent gravitational charge Q =√{ αGN } M. This new mass dependent charge modifies the effective Newtonian constant from GN to G =GN (1 + α), and this in turn critically affects the thermodynamics of the black holes. We also investigate the thermodynamics of regular solutions, and explore the limiting case when no horizons forms. So, it is possible that the modified gravity can lead to the absence of black hole horizons in our universe. Finally, we analyze corrections to the thermodynamics of a non-rotating black hole and obtain the usual logarithmic correction term.

  10. No supermassive black hole in M33?

    PubMed

    Merritt, D; Ferrarese, L; Joseph, C L

    2001-08-10

    We observed the nucleus of M33, the third-brightest galaxy in the Local Group, with the Space Telescope Imaging Spectrograph at a resolution at least a factor of 10 higher than previously obtained. Rather than the steep rise expected within the radius of gravitational influence of a supermassive black hole, the random stellar velocities showed a decrease within a parsec of the center of the galaxy. The implied upper limit on the mass of the central black hole is only 3000 solar masses, about three orders of magnitude lower than the dynamically inferred mass of any other supermassive black hole. Detecting black holes of only a few thousand solar masses is observationally challenging, but it is critical to establish how supermassive black holes relate to their host galaxies, and which mechanisms influence the formation and evolution of both.

  11. Supermassive Black Holes and Galaxy Evolution

    NASA Technical Reports Server (NTRS)

    Merritt, D.

    2004-01-01

    Supermassive black holes appear to be generic components of galactic nuclei. The formation and growth of black holes is intimately connected with the evolution of galaxies on a wide range of scales. For instance, mergers between galaxies containing nuclear black holes would produce supermassive binaries which eventually coalesce via the emission of gravitational radiation. The formation and decay of these binaries is expected to produce a number of observable signatures in the stellar distribution. Black holes can also affect the large-scale structure of galaxies by perturbing the orbits of stars that pass through the nucleus. Large-scale N-body simulations are beginning to generate testable predictions about these processes which will allow us to draw inferences about the formation history of supermassive black holes.

  12. Black hole thermodynamics based on unitary evolutions

    NASA Astrophysics Data System (ADS)

    Feng, Yu-Lei; Chen, Yi-Xin

    2015-10-01

    In this paper, we try to construct black hole thermodynamics based on the fact that the formation and evaporation of a black hole can be described by quantum unitary evolutions. First, we show that the Bekenstein-Hawking entropy SBH may not be a Boltzmann or thermal entropy. To confirm this statement, we show that the original black hole's ‘first law’ may not simply be treated as the first law of thermodynamics formally, due to some missing metric perturbations caused by matter. Then, by including those (quantum) metric perturbations, we show that the black hole formation and evaporation can be described effectively in a unitary manner, through a quantum channel between the exterior and interior of the event horizon. In this way, the paradoxes of information loss and firewall can be resolved effectively. Finally, we show that black hole thermodynamics can be constructed in an ordinary way, by constructing statistical mechanics.

  13. Numerical simulations of black-hole spacetimes

    NASA Astrophysics Data System (ADS)

    Chu, Tony

    This thesis covers various aspects of the numerical simulation of black-hole spacetimes according to Einstein's general theory of relativity, using the Spectral Einstein Code developed by the Caltech-Cornell-CITA collaboration. The first topic is improvement of binary-black-hole initial data. One such issue is the construction of binary-black-hole initial data with nearly extremal spins that remain nearly constant during the initial relaxation in an evolution. Another concern is the inclusion of physically realistic tidal deformations of the black holes to reduce the high-frequency components of the spurious gravitational radiation content, and represents a first step in incorporating post-Newtonian results in constraint-satisfying initial data. The next topic is the evolution of black-hole binaries and the gravitational waves they emit. The first spectral simulation of two inspiralling black holes through merger and ringdown is presented, in which the black holes are nonspinning and have equal masses. This work is extended to perform the first spectral simulations of two inspiralling black holes with moderate spins and equal masses, including the merger and ringdown. Two configurations are considered, in which both spins are either anti-aligned or aligned with the orbital angular momentum. Highly accurate gravitational waveforms are computed for all these cases, and are used to calibrate waveforms in the effective-one-body model. The final topic is the behavior of quasilocal black-hole horizons in highly dynamical situations. Simulations of a rotating black hole that is distort ed by a pulse of ingoing gravitational radiation are performed. Multiple marginally outer trapped surfaces are seen to appear and annihilate with each other during the evolution, and the world tubes th ey trace out are all dynamical horizons. The dynamical horizon and angular momentum flux laws are evaluated in this context, and the dynamical horizons are contrasted with the event horizon

  14. Hawking temperature of expanding cosmological black holes

    SciTech Connect

    Faraoni, Valerio

    2007-11-15

    In the context of a debate on the correct expression of the Hawking temperature of a cosmological black hole, we show that the correct expression in terms of the Hawking-Hayward quasilocal energy m{sub H} of the hole is T=(8{pi}m{sub H}(t)){sup -1}. This expression holds for comoving black holes and agrees with a recent proposal by Saida, Harada, and Maeda.

  15. Black hole as a wormhole factory

    NASA Astrophysics Data System (ADS)

    Kim, Sung-Won; Park, Mu-In

    2015-12-01

    There have been lots of debates about the final fate of an evaporating black hole and the singularity hidden by an event horizon in quantum gravity. However, on general grounds, one may argue that a black hole stops radiation at the Planck mass (ħc / G) 1 / 2 ∼10-5 g, where the radiated energy is comparable to the black hole's mass. And also, it has been argued that there would be a wormhole-like structure, known as "spacetime foam", due to large fluctuations below the Planck length (ħG /c3) 1 / 2 ∼10-33 cm. In this paper, as an explicit example, we consider an exact classical solution which represents nicely those two properties in a recently proposed quantum gravity model based on different scaling dimensions between space and time coordinates. The solution, called "Black Wormhole", consists of two different states, depending on its mass parameter M and an IR parameter ω: For the black hole state (with ωM2 > 1 / 2), a non-traversable wormhole occupies the interior region of the black hole around the singularity at the origin, whereas for the wormhole state (with ωM2 < 1 / 2), the interior wormhole is exposed to an outside observer as the black hole horizon is disappearing from evaporation. The black hole state becomes thermodynamically stable as it approaches the merging point where the interior wormhole throat and the black hole horizon merges, and the Hawking temperature vanishes at the exact merge point (with ωM2 = 1 / 2). This solution suggests the "Generalized Cosmic Censorship" by the existence of a wormhole-like structure which protects the naked singularity even after the black hole evaporation. One could understand the would-be wormhole inside the black hole horizon as the result of microscopic wormholes created by "negative" energy quanta which have entered the black hole horizon in Hawking radiation process; the quantum black hole could be a wormhole factory! It is found that this speculative picture may be consistent with the recent " ER

  16. Black holes in massive gravity

    NASA Astrophysics Data System (ADS)

    Babichev, Eugeny; Brito, Richard

    2015-08-01

    We review the black hole (BH) solutions of the ghost-free massive gravity theory and its bimetric extension, and outline the main results on the stability of these solutions against small perturbations. Massive (bi)-gravity accommodates exact BH solutions, analogous to those of general relativity (GR). In addition to these solutions, hairy BHs—solutions with no correspondent in GR—have been found numerically, whose existence is a natural consequence of the absence of Birkhoff’s theorem in these theories. The existence of extra propagating degrees of freedom, makes the stability properties of these BHs richer and more complex than those of GR. In particular, the bi-Schwarzschild BH exhibits an unstable spherically symmetric mode, while the bi-Kerr geometry is also generically unstable, both against the spherical mode and against superradiant instabilities. If astrophysical BHs are described by these solutions, the superradiant instability of the Kerr solution imposes stringent bounds on the graviton mass.

  17. 'Death Star' Galaxy Black Hole Fires at Neighboring Galaxy

    NASA Astrophysics Data System (ADS)

    2008-12-01

    This "death star" galaxy was discovered through the combined efforts of both space and ground-based telescopes. NASA's Chandra X-ray Observatory, Hubble Space Telescope, and Spitzer Space Telescope were part of the effort. The Very Large Array telescope, Socorro, N.M., and the Multi-Element Radio Linked Interferometer Network (MERLIN) telescopes in the United Kingdom also were needed for the finding. Illustration of Jet Striking Galaxy (unlabeled) Illustration of Jet Striking Galaxy (unlabeled) "We've seen many jets produced by black holes, but this is the first time we've seen one punch into another galaxy like we're seeing here," said Dan Evans, a scientist at the Harvard-Smithsonian Center for Astrophysics and leader of the study. "This jet could be causing all sorts of problems for the smaller galaxy it is pummeling." Jets from super massive black holes produce high amounts of radiation, especially high-energy X-rays and gamma-rays, which can be lethal in large quantities. The combined effects of this radiation and particles traveling at almost the speed of light could severely damage the atmospheres of planets lying in the path of the jet. For example, protective layers of ozone in the upper atmosphere of planets could be destroyed. X-ray & Radio Full Field Image of 3C321 X-ray & Radio Full Field Image of 3C321 Jets produced by super massive black holes transport enormous amounts of energy far from black holes and enable them to affect matter on scales vastly larger than the size of the black hole. Learning more about jets is a key goal for astrophysical research. "We see jets all over the Universe, but we're still struggling to understand some of their basic properties," said co-investigator Martin Hardcastle of the University of Hertfordshire, United Kingdom. "This system of 3C321 gives us a chance to learn how they're affected when they slam into something - like a galaxy - and what they do after that." Optical Image of 3C321 Optical Image of 3C321 The

  18. 'Death Star' Galaxy Black Hole Fires at Neighboring Galaxy

    NASA Astrophysics Data System (ADS)

    2007-12-01

    This "death star" galaxy was discovered through the combined efforts of both space and ground-based telescopes. NASA's Chandra X-ray Observatory, Hubble Space Telescope, and Spitzer Space Telescope were part of the effort. The Very Large Array telescope, Socorro, N.M., and the Multi-Element Radio Linked Interferometer Network (MERLIN) telescopes in the United Kingdom also were needed for the finding. Illustration of Jet Striking Galaxy (unlabeled) Illustration of Jet Striking Galaxy (unlabeled) "We've seen many jets produced by black holes, but this is the first time we've seen one punch into another galaxy like we're seeing here," said Dan Evans, a scientist at the Harvard-Smithsonian Center for Astrophysics and leader of the study. "This jet could be causing all sorts of problems for the smaller galaxy it is pummeling." Jets from super massive black holes produce high amounts of radiation, especially high-energy X-rays and gamma-rays, which can be lethal in large quantities. The combined effects of this radiation and particles traveling at almost the speed of light could severely damage the atmospheres of planets lying in the path of the jet. For example, protective layers of ozone in the upper atmosphere of planets could be destroyed. X-ray & Radio Full Field Image of 3C321 X-ray & Radio Full Field Image of 3C321 Jets produced by super massive black holes transport enormous amounts of energy far from black holes and enable them to affect matter on scales vastly larger than the size of the black hole. Learning more about jets is a key goal for astrophysical research. "We see jets all over the Universe, but we're still struggling to understand some of their basic properties," said co-investigator Martin Hardcastle of the University of Hertfordshire, United Kingdom. "This system of 3C321 gives us a chance to learn how they're affected when they slam into something - like a galaxy - and what they do after that." Optical Image of 3C321 Optical Image of 3C321 The

  19. Black holes in the Milky Way Galaxy

    PubMed Central

    Filippenko, Alexei V.

    1999-01-01

    Extremely strong observational evidence has recently been found for the presence of black holes orbiting a few relatively normal stars in our Milky Way Galaxy and also at the centers of some galaxies. The former generally have masses of 4–16 times the mass of the sun, whereas the latter are “supermassive black holes” with millions to billions of solar masses. The evidence for a supermassive black hole in the center of our galaxy is especially strong. PMID:10468548

  20. Dancing around the Black Hole

    NASA Astrophysics Data System (ADS)

    2001-08-01

    ISAAC Finds "Cool" Young Stellar Systems at the Centres of Active Galaxies Summary Supermassive Black Holes are present at the centres of many galaxies, some weighing hundreds of millions times more than the Sun. These extremely dense objects cannot be observed directly, but violently moving gas clouds and stars in their strong gravitational fields are responsible for the emission of energetic radiation from such "active galaxy nuclei" (AGN) . A heavy Black Hole feeds agressively on its surroundings . When the neighbouring gas and stars finally spiral into the Black Hole, a substantial fraction of the infalling mass is transformed into pure energy. However, it is not yet well understood how, long before this dramatic event takes place, all that material is moved from the outer regions of the galaxy towards the central region. So how is the food for the central Black Hole delivered to the table in the first place? To cast more light on this central question, a team of French and Swiss astronomers [1] has carried out a series of trailblazing observations with the VLT Infrared Spectrometer And Array Camera (ISAAC) on the VLT 8.2-m ANTU telescope at the ESO Paranal Observatory. The ISAAC instrument is particularly well suited to this type of observations. Visible light cannot penetrate the thick clouds of dust and gas in the innermost regions of active galaxies, but by recording the infrared light from the stars close to the Black Hole , their motions can be studied. By charting those motions in the central regions of three active galaxies (NGC 1097, NGC 1808 and NGC 5728), the astronomers were able to confirm the presence of "nuclear bars" in all three. These are dynamical structures that "open a road" for the flow of material towards the innermost region. Moreover, the team was surprised to discover signs of a young stellar population near the centres of these galaxies - stars that have apparently formed quite recently in a central gas disk. Such a system is unstable

  1. Revisiting Black Holes as Dark Matter

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2017-02-01

    Could dark matter be made of intermediate-mass black holes formed in the beginning of the universe? A recent study takes a renewed look at this question.Galactic LurkersThe nature of dark matter has long been questioned, but the recent discovery of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO) has renewed interest in the possibility that dark matter could consist of primordial black holes in the mass range of 101000 solar masses.The relative amounts of the different constituents of the universe. Dark matter makes up roughly 27%. [ESA/Planck]According to this model, the extreme density of matter present during the universes early expansion led to the formation of a large number of intermediate-mass black holes. These black holes now hide in the halos of galaxies, constituting the mass that weve measured dynamically but remains unseen.LIGOs first gravitational-wave detection revealed the merger of two black holes that were both tens of solar masses in size. If primordial black holes are indeed a major constituent of dark matter, then LIGOs detection is consistent with what we would expect to find: occasional mergers of the intermediate-mass black holes that formed in the early universe and now lurk in galactic halos.Quasar MicrolensingTheres a catch, however. If there truly were a large number of intermediate-mass primordial black holes hiding in galactic halos, they wouldnt go completely unnoticed: we would see signs of their presence in the gravitational microlensing of background quasars. Unseen primordial black holes in a foreground galaxy could cause an image of a background quasar to briefly brighten which would provide us with clear evidence of such black holes despite our not being able to detect them directly.A depiction of quasar microlensing (click for a closer look!). The microlensing object in the foreground galaxy could be a star (as depicted), a primordial black hole, or any other compact object. [NASA

  2. X-Ray Properties of Black-Hole Binaries

    NASA Astrophysics Data System (ADS)

    Remillard, Ronald A.; McClintock, Jeffrey E.

    2006-09-01

    We review the properties and behavior of 20 X-ray binaries that contain a dynamically-confirmed black hole, 17 of which are transient systems. During the past decade, many of these transient sources were observed daily throughout the course of their typically year-long outburst cycles using the large-area timing detector aboard the Rossi X-Ray Timing Explorer. The evolution of these transient sources is complex. Nevertheless, there are behavior patterns common to all of them as we show in a comprehensive comparison of six selected systems. Central to this comparison are three X-ray states of accretion, which are reviewed and defined quantitatively. We discuss phenomena that arise in strong gravitational fields, including relativistically-broadened Fe lines, high-frequency quasi-periodic oscillations (100 450 Hz), and relativistic radio and X-ray jets. Such phenomena show us how a black hole interacts with its environment, thereby complementing the picture of black holes that gravitational wave detectors will provide. We sketch a scenario for the potential impact of timing/spectral studies of accreting black holes on physics and discuss a current frontier topic, namely, the measurement of black hole spin.

  3. Gamma Ray Bursts and the Birth of Black Holes

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil

    2009-01-01

    Black holes have been predicted since the 1940's from solutions of Einstein's general relativity field equation. There is strong evidence of their existence from astronomical observations, but their origin has remained an open question of great interest. Gamma-ray bursts may the clue. They are powerful explosions, visible to high redshift, and appear to be the birth cries of black holes. The Swift and Fermi missions are two powerful NASA observatories currently in orbit that are discovering how gamma-ray bursts work. Evidence is building that the long and short duration subcategories of GRBs have very different origins: massive star core collapse to a black hole for long bursts and binary neutron star coalescence to a black hole for short bursts. The similarity to Type II and Ia supernovae originating from young and old stellar progenitors is striking. Bursts are tremendously luminous and are providing a new tool to study the high redshift universe. One Swift burst at z=8.3 is the most distant object known in the universe. The talk will present the latest gamma-ray burst results from Swift and Fermi and will highlight what they are teaching us about black holes and jet outflows.

  4. Suppression of star formation in early-type galaxies by feedback from supermassive black holes.

    PubMed

    Schawinski, Kevin; Khochfar, Sadegh; Kaviraj, Sugata; Yi, Sukyoung K; Boselli, Alessandro; Barlow, Tom; Conrow, Tim; Forster, Karl; Friedman, Peter G; Martin, D Chris; Morrissey, Patrick; Neff, Susan; Schiminovich, David; Seibert, Mark; Small, Todd; Wyder, Ted K; Bianchi, Luciana; Donas, Jose; Heckman, Tim; Lee, Young-Wook; Madore, Barry; Milliard, Bruno; Rich, R Michael; Szalay, Alex

    2006-08-24

    Detailed high-resolution observations of the innermost regions of nearby galaxies have revealed the presence of supermassive black holes. These black holes may interact with their host galaxies by means of 'feedback' in the form of energy and material jets; this feedback affects the evolution of the host and gives rise to observed relations between the black hole and the host. Here we report observations of the ultraviolet emissions of massive early-type galaxies. We derive an empirical relation for a critical black-hole mass (as a function of velocity dispersion) above which the outflows from these black holes suppress star formation in their hosts by heating and expelling all available cold gas. Supermassive black holes are negligible in mass compared to their hosts but nevertheless seem to play a critical role in the star formation history of galaxies.

  5. A VERY CLOSE BINARY BLACK HOLE IN A GIANT ELLIPTICAL GALAXY 3C 66B AND ITS BLACK HOLE MERGER

    SciTech Connect

    Iguchi, Satoru; Okuda, Takeshi; Sudou, Hiroshi E-mail: okuda@a.phys.nagoya-u.ac.j

    2010-12-01

    Recent observational results provide possible evidence that binary black holes (BBHs) exist in the center of giant galaxies and may merge to form a supermassive black hole in the process of their evolution. We first detected a periodic flux variation on a cycle of 93 {+-} 1 days from the 3 mm monitor observations of a giant elliptical galaxy 3C 66B for which an orbital motion with a period of 1.05 {+-} 0.03 yr had been already observed. The detected signal period being shorter than the orbital period can be explained by taking into consideration the Doppler-shifted modulation due to the orbital motion of a BBH. Assuming that the BBH has a circular orbit and that the jet axis is parallel to the binary angular momentum, our observational results demonstrate the presence of a very close BBH that has a binary orbit with an orbital period of 1.05 {+-} 0.03 yr, an orbital radius of (3.9 {+-} 1.0) x 10{sup -3} pc, an orbital separation of (6.1{sup +1.0} {sub -0.9}) x 10{sup -3} pc, a larger black hole mass of (1.2{sup +0.5} {sub -0.2}) x 10{sup 9} M {sub sun}, and a smaller black hole mass of (7.0{sup +4.7} {sub -6.4}) x 10{sup 8} M {sub sun}. The BBH decay time of (5.1{sup +60.5} {sub -2.5}) x 10{sup 2} yr provides evidence for the occurrence of black hole mergers. This Letter will demonstrate the interesting possibility of black hole collisions to form a supermassive black hole in the process of evolution, one of the most spectacular natural phenomena in the universe.

  6. Black Hole Mergers in the Universe.

    PubMed

    Portegies Zwart SF; McMillan

    2000-01-01

    Mergers of black hole binaries are expected to release large amounts of energy in the form of gravitational radiation. However, binary evolution models predict merger rates that are too low to be of observational interest. In this Letter, we explore the possibility that black holes become members of close binaries via dynamical interactions with other stars in dense stellar systems. In star clusters, black holes become the most massive objects within a few tens of millions of years; dynamical relaxation then causes them to sink to the cluster core, where they form binaries. These black hole binaries become more tightly bound by superelastic encounters with other cluster members and are ultimately ejected from the cluster. The majority of escaping black hole binaries have orbital periods short enough and eccentricities high enough that the emission of gravitational radiation causes them to coalesce within a few billion years. We predict a black hole merger rate of about 1.6x10-7 yr-1 Mpc-3, implying gravity-wave detection rates substantially greater than the corresponding rates from neutron star mergers. For the first-generation Laser Interferometer Gravitational-Wave Observatory (LIGO-I), we expect about one detection during the first 2 years of operation. For its successor LIGO-II, the rate rises to roughly one detection per day. The uncertainties in these numbers are large. Event rates may drop by about an order of magnitude if the most massive clusters eject their black hole binaries early in their evolution.

  7. Particle creation rate for dynamical black holes

    NASA Astrophysics Data System (ADS)

    Firouzjaee, Javad T.; Ellis, George F. R.

    2016-11-01

    We present the particle creation probability rate around a general black hole as an outcome of quantum fluctuations. Using the uncertainty principle for these fluctuation, we derive a new ultraviolet frequency cutoff for the radiation spectrum of a dynamical black hole. Using this frequency cutoff, we define the probability creation rate function for such black holes. We consider a dynamical Vaidya model and calculate the probability creation rate for this case when its horizon is in a slowly evolving phase. Our results show that one can expect the usual Hawking radiation emission process in the case of a dynamical black hole when it has a slowly evolving horizon. Moreover, calculating the probability rate for a dynamical black hole gives a measure of when Hawking radiation can be killed off by an incoming flux of matter or radiation. Our result strictly suggests that we have to revise the Hawking radiation expectation for primordial black holes that have grown substantially since they were created in the early universe. We also infer that this frequency cut off can be a parameter that shows the primordial black hole growth at the emission moment.

  8. Multipole moments of bumpy black holes

    SciTech Connect

    Vigeland, Sarah J.

    2010-11-15

    General relativity predicts the existence of black holes, compact objects whose spacetimes depend only on their mass, spin, and charge in vacuum (the 'no-hair' theorem). As various observations probe deeper into the strong fields of black hole candidates, it is becoming possible to test this prediction. Previous work suggested that such tests can be performed by measuring whether the multipolar structure of black hole candidates has the form that general relativity demands, and introduced a family of 'bumpy black hole' spacetimes to be used for making these measurements. These spacetimes have generalized multipoles, where the deviation from the Kerr metric depends on the spacetime's 'bumpiness'. In this paper, we show how to compute the Geroch-Hansen moments of a bumpy black hole, demonstrating that there is a clean mapping between the deviations used in the bumpy black hole formalism and the Geroch-Hansen moments. We also extend our previous results to define bumpy black holes whose current moments, analogous to magnetic moments of electrodynamics, deviate from the canonical Kerr value.

  9. Black hole formation in a contracting universe

    NASA Astrophysics Data System (ADS)

    Quintin, Jerome; Brandenberger, Robert H.

    2016-11-01

    We study the evolution of cosmological perturbations in a contracting universe. We aim to determine under which conditions density perturbations grow to form large inhomogeneities and collapse into black holes. Our method consists in solving the cosmological perturbation equations in complete generality for a hydrodynamical fluid. We then describe the evolution of the fluctuations over the different length scales of interest and as a function of the equation of state for the fluid, and we explore two different types of initial conditions: quantum vacuum and thermal fluctuations. We also derive a general requirement for black hole collapse on sub-Hubble scales, and we use the Press-Schechter formalism to describe the black hole formation probability. For a fluid with a small sound speed (e.g., dust), we find that both quantum and thermal initial fluctuations grow in a contracting universe, and the largest inhomogeneities that first collapse into black holes are of Hubble size and the collapse occurs well before reaching the Planck scale. For a radiation-dominated fluid, we find that no black hole can form before reaching the Planck scale. In the context of matter bounce cosmology, it thus appears that only models in which a radiation-dominated era begins early in the cosmological evolution are robust against the formation of black holes. Yet, the formation of black holes might be an interesting feature for other models. We comment on a number of possible alternative early universe scenarios that could take advantage of this feature.

  10. The Limits of Black Hole Complementarity

    NASA Astrophysics Data System (ADS)

    Susskind, Leonard

    Black hole complementarity, as originally formulated in the 1990's by Preskill, 't Hooft, and myself is now being challenged by the Almheiri-Marolf-Polchinski-Sully firewall argument. The AMPS argument relies on an implicit assumption—the "proximity" postulate—which says that the interior of a black hole must be constructed from degrees of freedom that are physically near the black hole. The proximity postulate manifestly contradicts the idea that interior information is redundant with information in Hawking radiation, which is very far from the black hole. AMPS argue that a violation of the proximity postulate would lead to a contradiction in a thought-experiment in which Alice distills the Hawking radiation and brings a bit back to the black hole. According to AMPS the only way to protect against the contradiction is for a firewall to form at the Page time. But the measurement that Alice must make, is of such a fine-grained nature that carrying it out before the black hole evaporates may be impossible. Harlow and Hayden have found evidence that the limits of quantum computation do in fact prevent Alice from carrying out her experiment in less than exponential time. If their conjecture is correct then black hole complementarity may be alive and well. My aim here is to give an overview of the firewall argument, and its basis in the proximity postulate; as well as the counterargument based on computational complexity, as conjectured by Harlow and Hayden.

  11. Black hole entanglement and quantum error correction

    NASA Astrophysics Data System (ADS)

    Verlinde, Erik; Verlinde, Herman

    2013-10-01

    It was recently argued in [1] that black hole complementarity strains the basic rules of quantum information theory, such as monogamy of entanglement. Motivated by this argument, we develop a practical framework for describing black hole evaporation via unitary time evolution, based on a holographic perspective in which all black hole degrees of freedom live on the stretched horizon. We model the horizon as a unitary quantum system with finite entropy, and do not postulate that the horizon geometry is smooth. We then show that, with mild assumptions, one can reconstruct local effective field theory observables that probe the black hole interior, and relative to which the state near the horizon looks like a local Minkowski vacuum. The reconstruction makes use of the formalism of quantum error correcting codes, and works for black hole states whose entanglement entropy does not yet saturate the Bekenstein-Hawking bound. Our general framework clarifies the black hole final state proposal, and allows a quantitative study of the transition into the "firewall" regime of maximally mixed black hole states.

  12. Some aspects of virtual black holes

    SciTech Connect

    Faizal, M.

    2012-03-15

    We first consider consistently third-quantize modified gravity. We then analyze certain aspects of virtual black holes in this third-quantized modified gravity. We see how a statistical mechanical origin for the Bekenstein-Hawking entropy naturally arises in this model. Furthermore, the area and hence the entropy of a real macroscopic black hole is quantized in this model. Virtual black holes cause a loss of quantum coherence, which gives an intrinsic entropy to all physical systems that can be used to define a direction of time and hence provide a solution to the problem of time.

  13. Entropy Inequality Violations from Ultraspinning Black Holes.

    PubMed

    Hennigar, Robie A; Mann, Robert B; Kubizňák, David

    2015-07-17

    We construct a new class of rotating anti-de Sitter (AdS) black hole solutions with noncompact event horizons of finite area in any dimension and study their thermodynamics. In four dimensions these black holes are solutions to gauged supergravity. We find that their entropy exceeds the maximum implied from the conjectured reverse isoperimetric inequality, which states that for a given thermodynamic volume, the black hole entropy is maximized for Schwarzschild-AdS space. We use this result to suggest more stringent conditions under which this conjecture may hold.

  14. Central black hole masses of galaxies

    NASA Astrophysics Data System (ADS)

    Fan, Jun-Hui

    2003-11-01

    In this paper, the stellar velocity dispersions in the host galaxies are used to estimate the central black hole masses for a sample of elliptical galaxies. We find that the central black hole masses are in the range of 10(5.5-9.5)Modot. Based on the estimated masses in this paper and those by Woo & Urry (2002) and the measured host galaxy absolute magnitude, a relation, log (MBH/Modot) = -(0.25±4.3×10-3)MR + (2.98±0.208) is found for central black hole mass and the host galaxy magnitude. Some discussions are presented.

  15. Entanglement entropy of subtracted geometry black holes

    NASA Astrophysics Data System (ADS)

    Cvetič, Mirjam; Saleem, Zain H.; Satz, Alejandro

    2014-09-01

    We compute the entanglement entropy of minimally coupled scalar fields on subtracted geometry black hole backgrounds, focusing on the logarithmic corrections. We notice that matching between the entanglement entropy of original black holes and their subtracted counterparts is only at the order of the area term. The logarithmic correction term is not only different but also, in general, changes sign in the subtracted case. We apply Harrison transformations to the original black holes and find out the choice of the Harrison parameters for which the logarithmic corrections vanish.

  16. Black Holes and the Information Paradox

    NASA Astrophysics Data System (ADS)

    't Hooft, Gerard

    In electromagnetism, like charges repel, opposite charges attract. A remarkable feature of the gravitational force is that like masses attract. This gives rise to an instability: the more mass you have, the stronger the attractive force, until an inevitable implosion follows, leading to a "black hole". It is in the black hole where an apparent conflict between Einstein's General Relativity and the laws of Quantum Mechanics becomes manifest. Most physicists now agree that a black hole should be described by a Schrödinger equation, with a Hermitean Hamiltonian, but this requires a modification of general relativity. Both General Relativity and Quantum mechanics are shaking on their foundations.

  17. Stationary Black Holes: Uniqueness and Beyond.

    PubMed

    Chruściel, Piotr T; Costa, João Lopes; Heusler, Markus

    2012-01-01

    The spectrum of known black-hole solutions to the stationary Einstein equations has been steadily increasing, sometimes in unexpected ways. In particular, it has turned out that not all black-hole-equilibrium configurations are characterized by their mass, angular momentum and global charges. Moreover, the high degree of symmetry displayed by vacuum and electro-vacuum black-hole spacetimes ceases to exist in self-gravitating non-linear field theories. This text aims to review some developments in the subject and to discuss them in light of the uniqueness theorem for the Einstein-Maxwell system.

  18. Microscopic Primordial Black Holes and Extra Dimensions

    SciTech Connect

    Conley, John A.; Wizansky, Tommer

    2006-11-15

    We examine the production and evolution of microscopic black holes in the early universe in the large extra dimensions scenario. We demonstrate that, unlike in the standard four-dimensional cosmology, in large extra dimensions absorption of matter from the primordial plasma by the black holes is significant and can lead to rapid growth of the black hole mass density. This effect can be used to constrain the conditions present in the very early universe. We demonstrate that this constraint is applicable in regions of parameter space not excluded by existing bounds.

  19. The primordial black hole mass range

    NASA Astrophysics Data System (ADS)

    Frampton, Paul H.

    2016-04-01

    We investigate Primordial Black Hole (PBH) formation by which we mean black holes produced in the early Universe during radiation domination. After discussing the range of PBH mass permitted in the original mechanism of Carr and Hawking, hybrid inflation with parametric resonance is presented as an existence theorem for PBHs of arbitrary mass. As proposed in arXiv:1510.00400, PBHs with many solar masses can provide a solution to the dark matter problem in galaxies. PBHs can also explain dark matter observed in clusters and suggest a primordial origin for Supermassive Black Holes (SMBHs) in galactic cores.

  20. Magnetically charged black holes and their stability

    SciTech Connect

    Aichelburg, P.C. ); Bizon, P. )

    1993-07-15

    We study magnetically charged black holes in the Einstein-Yang-Mills-Higgs theory in the limit of infinitely strong coupling of the Higgs field. Using mixed analytical and numerical methods we give a complete description of static spherically symmetric black hole solutions, both Abelian and non-Abelian. In particular, we find a new class of extremal non-Abelian solutions. We show that all non-Abelian solutions are stable against linear radial perturbations. The implications of our results for the semiclassical evolution of magnetically charged black holes are discussed.

  1. Three charge supertubes and black hole hair

    NASA Astrophysics Data System (ADS)

    Bena, Iosif; Kraus, Per

    2004-08-01

    We construct finite size, supersymmetric, tubular D-brane configurations with three charges, two angular momenta and several brane dipole moments. In type IIA string theory these are tubular configurations with D0, D4 and F1 charge, as well as D2, D6 and NS5 dipole moments. These multicharge generalizations of supertubes might have interesting consequences for the physics of the D1-D5-P black hole. We study the relation of the tubes to the spinning Breckenridge-Myers-Peet-Vafa black hole, and find that they have properties consistent with describing some of the hair of this black hole.

  2. Stellar black holes in globular clusters

    NASA Technical Reports Server (NTRS)

    Kulkarni, S. R.; Hut, Piet; Mcmillan, Steve

    1993-01-01

    The recent discovery of large populations of millisec pulsars associated with neutron stars in globular clusters indicates that several hundred stellar black holes of about 10 solar masses each can form within a typical cluster. While, in clusters of high central density, the rapid dynamical evolution of the black-hole population leads to an ejection of nearly all holes on a short timescale, systems of intermediate density may involve a normal star's capture by one of the surviving holes to form a low-mass X-ray binary. One or more such binaries may be found in the globular clusters surrounding our galaxy.

  3. Destruction and recreation of black holes

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    Even though the existence of the gravitationally collapsed concentrations of matter in space known as ‘black holes’ is accepted at all educational levels in our society, the basis for the black hole concept is really only the result of approximate calculations done over 40 years ago. The concept of the black hole is an esoteric subject, and recently the mathematical and physical frailties of the concept have come to light in an interesting round of theoretical shuffling. The recent activity in theorizing about black holes began about 10 years ago, when Cambridge University mathematican Stephen Hawking calculated that black holes could become unstable by losing mass and thus ‘evaporate.’ Hawking's results were surprisingly well received, considering the lack of theoretical understanding of the relations between quantum mechanics and relativity. (There is no quantized theory of gravitation, even today.) Nonetheless, his semiclassical calculations implied that the rate of ‘evaporation’ of a black hole would be slower than the rate of degradation of the universe. In fact, based on these and other calculations, the British regard Hawking as ‘the nearest thing we have to a new Einstein’ [New Scientist, Oct. 9, 1980]. Within the last few months, Frank Tipler, provocative mathematical physicist at the University of Texas, has reexamined Hawking's calculations [Physical Review Letters, 45, 941, 1980], concluding, in simple terms, (1) that because of possible vital difficulties in the assumptions, the very concept of black holes could be wrong; (2) that Hawkings' evaporation hypothesis is so efficient that a black hole once created must disappear in less than a second; or (3) that he, Tipler, may be wrong. The latter possibility has been the conclusion of physicist James Bardeen of the University of Washington, who calculated that black hole masses do evaporate but they do so according to Hawking's predicted rate and that Tipler's findings cause only a second

  4. Self stimulated particles generation by black holes

    NASA Astrophysics Data System (ADS)

    Gaina, Alex

    2005-10-01

    The Ideea of Black Holes Bomb was one of the most intriguing in the gravitational physics. Bohr was the first who quantized the levels of an atom. Subsequently his disciple J. A. Wheeler (1971) quantized the mass spin 0 and 1/2 levels near a black hole, described by a Schwarzschild metric. It is strange, but after this work the interest was drawn to Kerr black holes, due to discovery of particles generation by Ya. B. Zel'dovich and Ch. Misner in 1972. As a result, the ideea of a Black Holes bomb was announced by W.H. Press and S. Teukolsky in 1972. L.Ford (1975) observed, that test particles mass plays a role of a mirror, which could develope an instability. That ideea was independently discussed by Deruelle and Ruffini (1974) and Damour, Deruelle and Rufffini (1976), using WKB approach, while the analytic treatment of the bound levels problem in Kerr field for microscopically small black holes and mass particles was given by Ternov, Khalilov, Chizhov and Gaina (1978) and A. Vilenkin (1978) for a Kerr black hole inside a mirror. Once a particle could be localized on a bound level near a non-rotating (Schwarzschild ) black hole, due to stimulation, it will induces generation of another particles with the same quantum numbers (on the same level). This process will be a self-stimulated generation of particles, which was discussed in the literature by R. Wald and J. York, Jr. The accumulatiion of bosons on the bound levels, particularly on the s-bound level, will be exponentially fast for microscopically small black holes and will lead to a true instablity of Schwarzschild black holes. This is valid for bosons only, since the Fermi-Dirac statistics interdicts the accumulation of more than two particles with oposite spin. As a result the Black Holes mass will be limited M>= 8"pi"/5 x (M(pl))^2/m , where m is the scalar particles minimal rest mass, existing in nature, since the maximal growing rate for the instability is occuring for mM=8"pi"/5(M(pl))^2. If photon have a

  5. Skyrmion black hole hair: Conservation of baryon number by black holes and observable manifestations

    NASA Astrophysics Data System (ADS)

    Dvali, Gia; Gußmann, Alexander

    2016-12-01

    We show that the existence of black holes with classical skyrmion hair invalidates standard proofs that global charges, such as the baryon number, cannot be conserved by a black hole. By carefully analyzing the standard arguments based on a Gedankenexperiment in which a black hole is seemingly-unable to return the baryon number that it swallowed, we identify inconsistencies in this reasoning, which does not take into the account neither the existence of skyrmion black holes nor the baryon/skyrmion correspondence. We then perform a refined Gedankenexperiment by incorporating the new knowledge and show that no contradiction with conservation of baryon number takes place at any stage of black hole evolution. Our analysis also indicates no conflict between semi-classical black holes and the existence of baryonic gauge interaction arbitrarily-weaker than gravity. Next, we study classical cross sections of a minimally-coupled massless probe scalar field scattered by a skyrmion black hole. We investigate how the skyrmion hair manifests itself by comparing this cross section with the analogous cross section caused by a Schwarzschild black hole which has the same ADM mass as the skyrmion black hole. Here we find an order-one difference in the positions of the characteristic peaks in the cross sections. The peaks are shifted to smaller scattering angles when the skyrmion hair is present. This comes from the fact that the skyrmion hair changes the near horizon geometry of the black hole when compared to a Schwarzschild black hole with same ADM mass. We keep the study of this second aspect general so that the qualitative results which we obtain can also be applied to black holes with classical hair of different kind.

  6. Thermodynamics of the Schwarzschild-de Sitter black hole: Thermal stability of the Nariai black hole

    SciTech Connect

    Myung, Yun Soo

    2008-05-15

    We study the thermodynamics of the Schwarzschild-de Sitter black hole in five dimensions by introducing two temperatures based on the standard and Bousso-Hawking normalizations. We use the first-law of thermodynamics to derive thermodynamic quantities. The two temperatures indicate that the Nariai black hole is thermodynamically unstable. However, it seems that black hole thermodynamics favors the standard normalization and does not favor the Bousso-Hawking normalization.

  7. Black holes, bandwidths and Beethoven

    NASA Astrophysics Data System (ADS)

    Kempf, Achim

    2000-04-01

    It is usually believed that a function φ(t) whose Fourier spectrum is bounded can vary at most as fast as its highest frequency component ωmax. This is, in fact, not the case, as Aharonov, Berry, and others drastically demonstrated with explicit counterexamples, so-called superoscillations. It has been claimed that even the recording of an entire Beethoven symphony can occur as part of a signal with a 1 Hz bandwidth. Bandlimited functions also occur as ultraviolet regularized fields. Their superoscillations have been suggested, for example, to resolve the trans-Planckian frequencies problem of black hole radiation. Here, we give an exact proof for generic superoscillations. Namely, we show that for every fixed bandwidth there exist functions that pass through any finite number of arbitrarily prespecified points. Further, we show that, in spite of the presence of superoscillations, the behavior of bandlimited functions can be characterized reliably, namely through an uncertainty relation: The standard deviation ΔT of samples φ(tn) taken at the Nyquist rate obeys ΔT>=1/4ωmax. This uncertainty relation generalizes to variable bandwidths. For ultraviolet regularized fields we identify the bandwidth as the in general spatially variable finite local density of degrees of freedom.

  8. Creating a urine black hole

    NASA Astrophysics Data System (ADS)

    Hurd, Randy; Pan, Zhao; Meritt, Andrew; Belden, Jesse; Truscott, Tadd

    2015-11-01

    Since the mid-nineteenth century, both enlisted and fashion-conscious owners of khaki trousers have been plagued by undesired speckle patterns resulting from splash-back while urinating. In recent years, industrial designers and hygiene-driven entrepreneurs have sought to limit this splashing by creating urinal inserts, with the effectiveness of their inventions varying drastically. From this large assortment of inserts, designs consisting of macroscopic pillar arrays seem to be the most effective splash suppressers. Interestingly this design partially mimics the geometry of the water capturing moss Syntrichia caninervis, which exhibits a notable ability to suppress splash and quickly absorb water from impacting rain droplets. With this natural splash suppressor in mind, we search for the ideal urine black hole by performing experiments of simulated urine streams (water droplet streams) impacting macroscopic pillar arrays with varying parameters including pillar height and spacing, draining and material properties. We propose improved urinal insert designs based on our experimental data in hopes of reducing potential embarrassment inherent in wearing khakis.

  9. Black holes as gravitational atoms

    NASA Astrophysics Data System (ADS)

    Vaz, Cenalo

    2014-06-01

    Recently, it was argued [A. Almheiri et al., arXiv: 1207.3123, A. Almheiri et al., arXiv: 1304.6483], via a delicate thought experiment, that it is not consistent to simultaneously require that (a) Hawking radiation is pure, (b) effective field theory is valid outside a stretched horizon and (c) infalling observers encounter nothing unusual as they cross the horizon. These are the three fundamental assumptions underlying Black Hole Complementarity and the authors proposed that the most conservative resolution of the paradox is that (c) is false and the infalling observer burns up at the horizon (the horizon acts as a "firewall"). However, the firewall violates the equivalence principle and breaks the CPT invariance of quantum gravity. This led Hawking to propose recently that gravitational collapse may not end up producing event horizons, although he did not give a mechanism for how this may happen. Here we will support Hawking's conclusion in a quantum gravitational model of dust collapse. We will show that continued collapse to a singularity can only be achieved by combining two independent and entire solutions of the Wheeler-DeWitt equation. We interpret the paradox as simply forbidding such a combination. This leads naturally to a picture in which matter condenses on the apparent horizon during quantum collapse.

  10. The 'Heartbeats' of Flaring Black Holes

    NASA Video Gallery

    This animation compares the X-ray 'heartbeats' of GRS 1915 and IGR J17091, two black holes that ingest gas from companion stars. GRS 1915 has nearly five times the mass of IGR J17091, which at thre...

  11. Spectral line broadening in magnetized black holes

    SciTech Connect

    Frolov, Valeri P.; Shoom, Andrey A.; Tzounis, Christos E-mail: ashoom@ualberta.ca

    2014-07-01

    We consider weakly magnetized non-rotating black holes. In the presence of a regular magnetic field the motion of charged particles in the vicinity of a black hole is modified. As a result, the position of the innermost stable circular orbit (ISCO) becomes closer to the horizon. When the Lorentz force is repulsive (directed from the black hole) the ISCO radius can reach the gravitational radius. In the process of accretion charged particles (ions) of the accreting matter can be accumulated near their ISCO, while neutral particles fall down to the black hole after they reach 6M radius. The sharp spectral line Fe α, emitted by iron ions at such orbits, is broadened when the emission is registered by a distant observer. In this paper we study this broadening effect and discuss how one can extract information concerning the strength of the magnetic field from the observed spectrum.

  12. White Dwarfs, Neutron Stars and Black Holes

    ERIC Educational Resources Information Center

    Szekeres, P.

    1977-01-01

    The three possible fates of burned-out stars: white dwarfs, neutron stars and black holes, are described in elementary terms. Characteristics of these celestial bodies, as provided by Einstein's work, are described. (CP)

  13. Black Holes: The making of a monster

    NASA Astrophysics Data System (ADS)

    Mayer, Lucio

    2017-04-01

    The biggest black holes in the Universe were in place soon after the Big Bang. Explaining how they formed so rapidly is a daunting challenge, but the latest simulations give clues to how this may have occurred.

  14. Mass of a black hole firewall.

    PubMed

    Abramowicz, M A; Kluźniak, W; Lasota, J-P

    2014-03-07

    Quantum entanglement of Hawking radiation has been supposed to give rise to a Planck density "firewall" near the event horizon of old black holes. We show that Planck density firewalls are excluded by Einstein's equations for black holes of mass exceeding the Planck mass. We find an upper limit of 1/(8πM) to the surface density of a firewall in a Schwarzschild black hole of mass M, translating for astrophysical black holes into a firewall density smaller than the Planck density by more than 30 orders of magnitude. A strict upper limit on the firewall density is given by the Planck density times the ratio M(Pl)/(8πM).

  15. Charged fermions tunneling from regular black holes

    SciTech Connect

    Sharif, M. Javed, W.

    2012-11-15

    We study Hawking radiation of charged fermions as a tunneling process from charged regular black holes, i.e., the Bardeen and ABGB black holes. For this purpose, we apply the semiclassical WKB approximation to the general covariant Dirac equation for charged particles and evaluate the tunneling probabilities. We recover the Hawking temperature corresponding to these charged regular black holes. Further, we consider the back-reaction effects of the emitted spin particles from black holes and calculate their corresponding quantum corrections to the radiation spectrum. We find that this radiation spectrum is not purely thermal due to the energy and charge conservation but has some corrections. In the absence of charge, e = 0, our results are consistent with those already present in the literature.

  16. Merging Black Holes and Gravitational Waves

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2009-01-01

    This talk will focus on simulations of binary black hole mergers and the gravitational wave signals they produce. Applications to gravitational wave detection with LISA, and electronagnetic counterparts, will be highlighted.

  17. Quasars, pulsars, black holes and HEAO's

    NASA Technical Reports Server (NTRS)

    Doolitte, R. F.; Moritz, K.; Whilden, R. D. C.

    1974-01-01

    Astronomical surveys are discussed by large X-ray, gamma ray, and cosmic ray instruments carried onboard high-energy astronomy observatories. Quasars, pulsars, black holes, and the ultimate benefits of the new astronomy are briefly discussed.

  18. Black holes and the positive cosmological constant

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Sourav

    2013-02-01

    We address some aspects of black hole spacetimes endowed with a positive cosmological constant, i.e. black holes located inside a cosmological event horizon. First we establish a general criterion for existence of cosmological event horizons. Using the geometrical set up built for this, we study classical black hole no hair theorems for both static and stationary axisymmetric spacetimes. We discuss cosmic Nielsen-Olesen strings as hair in Schwarzschild-de Sitter spacetime. We also give a general calculation for particle creation by a Killing horizon using complex path analysis and using this we study particle creation in Schwarzschild-de Sitter spacetime by both black hole and the cosmological event horizons.

  19. Charged dilatonic black holes in gravity's rainbow

    NASA Astrophysics Data System (ADS)

    Hendi, S. H.; Faizal, Mir; Panah, B. Eslam; Panahiyan, S.

    2016-05-01

    In this paper, we present charged dilatonic black holes in gravity's rainbow. We study the geometric and thermodynamic properties of black hole solutions. We also investigate the effects of rainbow functions on different thermodynamic quantities for these charged black holes in dilatonic gravity's rainbow. Then we demonstrate that the first law of thermodynamics is valid for these solutions. After that, we investigate thermal stability of the solutions using the canonical ensemble and analyze the effects of different rainbow functions on the thermal stability. In addition, we present some arguments regarding the bound and phase transition points in context of geometrical thermodynamics. We also study the phase transition in extended phase space in which the cosmological constant is treated as the thermodynamic pressure. Finally, we use another approach to calculate and demonstrate that the obtained critical points in extended phase space represent a second order phase transition for these black holes.

  20. Interior of a charged distorted black hole

    SciTech Connect

    Abdolrahimi, Shohreh; Frolov, Valeri P.; Shoom, Andrey A.

    2009-07-15

    We study the interior of a charged, nonrotating distorted black hole. We consider static and axisymmetric black holes, and focus on a special case when an electrically charged distorted solution is obtained by the Harrison-Ernst transformation from an uncharged one. We demonstrate that the Cauchy horizon of such a black hole remains regular, provided the distortion is regular at the event horizon. The shape and the inner geometry of both the outer and inner (Cauchy) horizons are studied. We demonstrate that there exists a duality between the properties of the horizons. Proper time of a free fall of a test particle moving in the interior of the distorted black hole along the symmetry axis is calculated. We also study the property of the curvature in the inner domain between the horizons. Simple relations between the 4D curvature invariants and the Gaussian curvature of the outer and inner horizon surfaces are found.

  1. Black hole evolution by spectral methods

    NASA Astrophysics Data System (ADS)

    Kidder, Lawrence E.; Scheel, Mark A.; Teukolsky, Saul A.; Carlson, Eric D.; Cook, Gregory B.

    2000-10-01

    Current methods of evolving a spacetime containing one or more black holes are plagued by instabilities that prohibit long-term evolution. Some of these instabilities may be due to the numerical method used, traditionally finite differencing. In this paper, we explore the use of a pseudospectral collocation (PSC) method for the evolution of a spherically symmetric black hole spacetime in one dimension using a hyperbolic formulation of Einstein's equations. We demonstrate that our PSC method is able to evolve a spherically symmetric black hole spacetime forever without enforcing constraints, even if we add dynamics via a Klein-Gordon scalar field. We find that, in contrast with finite-differencing methods, black hole excision is a trivial operation using PSC applied to a hyperbolic formulation of Einstein's equations. We discuss the extension of this method to three spatial dimensions.

  2. Black hole evaporation rates without spacetime.

    PubMed

    Braunstein, Samuel L; Patra, Manas K

    2011-08-12

    Verlinde recently suggested that gravity, inertia, and even spacetime may be emergent properties of an underlying thermodynamic theory. This vision was motivated in part by Jacobson's 1995 surprise result that the Einstein equations of gravity follow from the thermodynamic properties of event horizons. Taking a first tentative step in such a program, we derive the evaporation rate (or radiation spectrum) from black hole event horizons in a spacetime-free manner. Our result relies on a Hilbert space description of black hole evaporation, symmetries therein which follow from the inherent high dimensionality of black holes, global conservation of the no-hair quantities, and the existence of Penrose processes. Our analysis is not wedded to standard general relativity and so should apply to extended gravity theories where we find that the black hole area must be replaced by some other property in any generalized area theorem.

  3. Primordial Black Holes from First Principles (Overview)

    NASA Astrophysics Data System (ADS)

    Lam, Casey; Bloomfield, Jolyon; Moss, Zander; Russell, Megan; Face, Stephen; Guth, Alan

    2017-01-01

    Given a power spectrum from inflation, our goal is to calculate, from first principles, the number density and mass spectrum of primordial black holes that form in the early universe. Previously, these have been calculated using the Press- Schechter formalism and some demonstrably dubious rules of thumb regarding predictions of black hole collapse. Instead, we use Monte Carlo integration methods to sample field configurations from a power spectrum combined with numerical relativity simulations to obtain a more accurate picture of primordial black hole formation. We demonstrate how this can be applied for both Gaussian perturbations and the more interesting (for primordial black holes) theory of hybrid inflation. One of the tools that we employ is a variant of the BBKS formalism for computing the statistics of density peaks in the early universe. We discuss the issue of overcounting due to subpeaks that can arise from this approach (the ``cloud-in-cloud'' problem). MIT UROP Office- Paul E. Gray (1954) Endowed Fund.

  4. Gravitational radiation from extreme Kerr black hole

    NASA Technical Reports Server (NTRS)

    Sasaki, Misao; Nakamura, Takashi

    1989-01-01

    Gravitational radiation induced by a test particle falling into an extreme Kerr black hole was investigated analytically. Assuming the radiation is dominated by the infinite sequence of quasi-normal modes which has the limiting frequency m/(2M), where m is an azimuthal eigenvalue and M is the mass of the black hole, it was found that the radiated energy diverges logarithmically in time. Then the back reaction to the black hole was evaluated by appealing to the energy and angular momentum conservation laws. It was found that the radiation has a tendency to increase the ratio of the angular momentum to mass of the black hole, which is completely different from non-extreme case, while the contribution of the test particle is to decrease it.

  5. CFT duals for accelerating black holes

    NASA Astrophysics Data System (ADS)

    Astorino, Marco

    2016-09-01

    The near horizon geometry of the rotating C-metric, describing accelerating Kerr-Newman black holes, is analysed. It is shown that, at extremality, even though it is not isomorphic to the extremal Kerr-Newman, it remains a warped and twisted product of AdS2 ×S2. Therefore the methods of the Kerr/CFT correspondence can successfully be applied to build a CFT dual model, whose entropy reproduces, through the Cardy formula, the Bekenstein-Hawking entropy of the accelerating black hole. The mass of accelerating Kerr-Newman black hole, which fulfils the first law of thermodynamics, is presented. Further generalisation in presence of an external Melvin-like magnetic field, used to regularise the conical singularity characteristic of the C-metrics, shows that the Kerr/CFT correspondence can be applied also for the accelerating and magnetised extremal black holes.

  6. Energy conservation for dynamical black holes.

    PubMed

    Hayward, Sean A

    2004-12-17

    An energy conservation law is described, expressing the increase in mass-energy of a general black hole in terms of the energy densities of the infalling matter and gravitational radiation. This first law of black-hole dynamics describes how a black hole grows and is regular in the limit where it ceases to grow. An effective gravitational-radiation energy tensor is obtained, providing measures of both ingoing and outgoing, transverse and longitudinal gravitational radiation on and near a black hole. Corresponding energy-tensor forms of the first law involve a preferred time vector which plays the role of a stationary Killing vector. Identifying an energy flux, vanishing if and only if the horizon is null, allows a division into energy supply and work terms. The energy supply can be expressed in terms of area increase and a newly defined surface gravity, yielding a Gibbs-like equation.

  7. The signature of a black hole transit

    NASA Technical Reports Server (NTRS)

    Dolan, Joseph F.

    1989-01-01

    This paper considers the possibility of identifying a black hole on the basis of the detection of some unique effect occurring during the transit of a black hole across the stellar disk of a companion star in a binary system. The results of Monte-Carlo calculations show that the amplitude of the photometric and polarimetric light curves in a typical X-ray binary is too small to be observed with present instrumentation, but that a black hole transit might be detectable in a binary having a large separation of the components. No binary system suggested as containing a stellar-mass-sized black hole is a like candidate to exhibit an observable transit signature, with the possible exception of X Persei/4U0352+30 described by White et al. (1976).

  8. Shadow of rotating regular black holes

    NASA Astrophysics Data System (ADS)

    Abdujabbarov, Ahmadjon; Amir, Muhammed; Ahmedov, Bobomurat; Ghosh, Sushant G.

    2016-05-01

    We study the shadows cast by the different types of rotating regular black holes viz. Ayón-Beato-García (ABG), Hayward, and Bardeen. These black holes have in addition to the total mass (M ) and rotation parameter (a ), different parameters as electric charge (Q ), deviation parameter (g ), and magnetic charge (g*). Interestingly, the size of the shadow is affected by these parameters in addition to the rotation parameter. We found that the radius of the shadow in each case decreases monotonically, and the distortion parameter increases when the values of these parameters increase. A comparison with the standard Kerr case is also investigated. We have also studied the influence of the plasma environment around regular black holes to discuss its shadow. The presence of the plasma affects the apparent size of the regular black hole's shadow to be increased due to two effects: (i) gravitational redshift of the photons and (ii) radial dependence of plasma density.

  9. Spherical boson stars as black hole mimickers

    SciTech Connect

    Guzman, F. S.; Rueda-Becerril, J. M.

    2009-10-15

    We present spherically symmetric boson stars as black hole mimickers based on the power spectrum of a simple accretion disk model. The free parameters of the boson star are the mass of the boson and the fourth-order self-interaction coefficient in the scalar field potential. We show that even if the mass of the boson is the only free parameter, it is possible to find a configuration that mimics the power spectrum of the disk due to a black hole of the same mass. We also show that for each value of the self-interaction a single boson star configuration can mimic a black hole at very different astrophysical scales in terms of the mass of the object and the accretion rate. In order to show that it is possible to distinguish one of our mimickers from a black hole, we also study the deflection of light.

  10. Mass of a Black Hole Firewall

    NASA Astrophysics Data System (ADS)

    Abramowicz, M. A.; Kluźniak, W.; Lasota, J.-P.

    2014-03-01

    Quantum entanglement of Hawking radiation has been supposed to give rise to a Planck density "firewall" near the event horizon of old black holes. We show that Planck density firewalls are excluded by Einstein's equations for black holes of mass exceeding the Planck mass. We find an upper limit of 1/(8πM) to the surface density of a firewall in a Schwarzschild black hole of mass M, translating for astrophysical black holes into a firewall density smaller than the Planck density by more than 30 orders of magnitude. A strict upper limit on the firewall density is given by the Planck density times the ratio MPl/(8πM).

  11. An unusually massive stellar black hole in the Galaxy.

    PubMed

    Greiner, J; Cuby, J G; McCaughrean, M J

    2001-11-29

    The X-ray source known as GRS1915+105 belongs to a group dubbed 'microquasars'. These objects are binary systems which sporadically eject matter at speeds that appear superluminal, as is the case for some quasars. GRS1915+105 is also one of only two known binary sources thought to contain a maximally spinning black hole. Determining the basic parameters of GRS195+105, such as the masses of the components, will help us to understand jet formation in this system, as well as providing links to other objects which exhibit jets. Using X-ray data, indirect methods have previously been used to infer a variety of masses for the accreting compact object in the range 10-30 solar masses (M middle dot in circle). Here we report a direct measurement of the orbital period and mass function of GRS1915+105, which allow us to deduce a mass of 14 +/- 4 M middle dot in circle for the black hole. Black holes with masses >5-7 M middle dot in circle challenge the conventional picture of black-hole formation in binary systems. Based on the mass estimate, we interpret the distinct X-ray variability of GRS1915+105 as arising from instabilities in an accretion disk that is dominated by radiation pressure, and radiating near the Eddington limit (the point where radiation pressure supports matter against gravity). Also, the mass estimate constrains most models which relate observable X-ray properties to the spin of black holes in microquasars.

  12. Improved black hole fireworks: Asymmetric black-hole-to-white-hole tunneling scenario

    NASA Astrophysics Data System (ADS)

    De Lorenzo, Tommaso; Perez, Alejandro

    2016-06-01

    A new scenario for gravitational collapse has been recently proposed by Haggard and Rovelli. Presenting the model under the name of black hole fireworks, they claim that the accumulation of quantum gravitational effects outside the horizon can cause the tunneling of geometry from a black hole to a white hole, allowing a bounce of the collapsing star which can eventually go back to infinity. In this paper, we discuss the instabilities of this model and propose a simple minimal modification which eliminates them, as well as other related instabilities discussed in the literature. The new scenario is a time-asymmetric version of the original model with a time scale for the final explosion that is shorter than m log m in Planck units. Our analysis highlights the importance of irreversibility in gravitational collapse which, in turn, uncovers important issues that cannot be addressed in detail without a full quantum gravity treatment.

  13. Black Hole Solutions and Pair Creation of Black Holes in Three, Four and Higher Dimensional Spacetimes

    NASA Astrophysics Data System (ADS)

    Dias, Oscar J. C.

    2004-10-01

    Black holes, first found as solutions of Einstein's General Relativity, are important in astrophysics, since they result from the gravitational collapse of a massive star or a cluster of stars, and in physics since they reveal properties of the fundamental physics, such as thermodynamic and quantum properties of gravitation. In order to better understand the black hole physics we need exact solutions that describe one or more black holes. In this thesis we study exact solutions in three, four and higher dimensional spacetimes. The study in 3-dimensions is important due to the simplification of the problem, while the discussion in higher dimensions is essential due to the fact that many theories indicate that extra dimensions exist in our universe. In this thesis, in any of the dimensions mentioned above, we study exact solutions with a single black hole and exact solutions that describe a pair of uniformly accelerated black holes (C-metric), with the acceleration source being well identified. This later solutions are then used to study in detail the quantum process of black hole pair creation in an external field. We also compute the gravitational radiation released during this pair creation process. KEYWORDS: Exact black hole solutions; Pair of accelerated black holes, C-metric, Ernst solution; Pair creation of black holes; Gravitational radiation; D-dimensional spacetimes; Cosmological constant backgrounds.

  14. Black hole evolution - I. Supernova-regulated black hole growth

    NASA Astrophysics Data System (ADS)

    Dubois, Yohan; Volonteri, Marta; Silk, Joseph; Devriendt, Julien; Slyz, Adrianne; Teyssier, Romain

    2015-09-01

    The growth of a supermassive black hole (BH) is determined by how much gas the host galaxy is able to feed it, which in turn is controlled by the cosmic environment, through galaxy mergers and accretion of cosmic flows that time how galaxies obtain their gas, and also by internal processes in the galaxy, such as star formation and feedback from stars and the BH itself. In this paper, we study the growth of a 1012 M⊙ halo at z = 2, which is the progenitor of a group of galaxies at z = 0, and of its central BH by means of a high-resolution zoomed cosmological simulation, the Seth simulation. We study the evolution of the BH driven by the accretion of cold gas in the galaxy, and explore the efficiency of the feedback from supernovae (SNe). For a relatively inefficient energy input from SNe, the BH grows at the Eddington rate from early times, and reaches self-regulation once it is massive enough. We find that at early cosmic times z > 3.5, efficient feedback from SNe forbids the formation of a settled disc as well as the accumulation of dense cold gas in the vicinity of the BH and starves the central compact object. As the galaxy and its halo accumulate mass, they become able to confine the nuclear inflows provided by major mergers and the BH grows at a sustained near-to-Eddington accretion rate. We argue that this mechanism should be ubiquitous amongst low-mass galaxies, corresponding to galaxies with a stellar mass below ≲ 109 M⊙ in our simulations.

  15. Local temperature for dynamical black holes

    SciTech Connect

    Hayward, Sean A.; Di Criscienzo, R.; Nadalini, M.; Vanzo, L.; Zerbini, S.

    2009-05-01

    A local Hawking temperature was recently derived for any future outer trapping horizon in spherical symmetry, using a Hamilton-Jacobi tunneling method, and is given by a dynamical surface gravity as defined geometrically. Descriptions are given of the operational meaning of the temperature, in terms of what observers measure, and its relation to the usual Hawking temperature for static black holes. Implications for the final fate of an evaporating black hole are discussed.

  16. Strongly Magnetized Accretion Disks Around Black Holes

    NASA Astrophysics Data System (ADS)

    Salvesen, Greg; Armitage, Philip J.; Simon, Jacob B.; Begelman, Mitchell C.

    2017-01-01

    Recent observations are suggestive of strongly magnetized accretion disks around black holes. Performing local (shearing box) simulations of accretion disks, we investigate how a strong magnetization state can develop and persist. We demonstrate that poloidal flux is a necessary prerequisite for the sustainability of strongly magnetized accretion disks. We also show that black hole spin measurements can become unconstrained if magnetic fields provide a significant contribution to the vertical pressure support of the accretion disk atmosphere.

  17. Entanglement thermodynamics for charged black holes

    NASA Astrophysics Data System (ADS)

    Chaturvedi, Pankaj; Malvimat, Vinay; Sengupta, Gautam

    2016-09-01

    The holographic quantum entanglement entropy for an infinite strip region of the boundary for the field theory dual to charged black holes in A d S3 +1 is investigated. In this framework we elucidate the low and high temperature behavior of the entanglement entropy pertaining to various limits of the black hole charge. In the low temperature regime we establish a first law of entanglement thermodynamics for the boundary field theory.

  18. Transonic disk accretion onto black holes

    NASA Technical Reports Server (NTRS)

    Liang, E. P. T.; Thompson, K. A.

    1980-01-01

    The solution for the radial drift velocity of thin disk accretion onto black holes must be transonic, and is analogous to the critical solution in spherical Bondi accretion, except for the presence of angular momentum. The transonic requirement yields a correct treatment of the inner region of the disk not found in the conventional Keplerian models and may lead to significantly different overall disk structures. Possible observational consequences, relevant to the black hole hypothesis for Cyg X-1 and other candidates, are discussed.

  19. Rotating black holes in dilatonic Einstein-Gauss-Bonnet theory.

    PubMed

    Kleihaus, Burkhard; Kunz, Jutta; Radu, Eugen

    2011-04-15

    We construct generalizations of the Kerr black holes by including higher-curvature corrections in the form of the Gauss-Bonnet density coupled to the dilaton. We show that the domain of existence of these Einstein-Gauss-Bonnet-dilaton (EGBD) black holes is bounded by the Kerr black holes, the critical EGBD black holes, and the singular extremal EGBD solutions. The angular momentum of the EGBD black holes can exceed the Kerr bound. The EGBD black holes satisfy a generalized Smarr relation. We also compare their innermost stable circular orbits with those of the Kerr black holes and show the existence of differences which might be observable in astrophysical systems.

  20. Black holes as bubble nucleation sites

    NASA Astrophysics Data System (ADS)

    Gregory, Ruth; Moss, Ian G.; Withers, Benjamin

    2014-03-01

    We consider the effect of inhomogeneities on the rate of false vacuum decay. Modelling the inhomogeneity by a black hole, we construct explicit Euclidean instantons which describe the nucleation of a bubble of true vacuum centred on the inhomogeneity. We find that inhomogeneity significantly enhances the nucleation rate over that of the Coleman-de Luccia instanton — the black hole acts as a nucleation site for the bubble. The effect is larger than previously believed due to the contributions to the action from conical singularities. For a sufficiently low initial mass, the original black hole is replaced by flat space during this process, as viewed by a single causal patch observer. Increasing the initial mass, we find a critical value above which a black hole remnant survives the process. This resulting black hole can have a higher mass than the original black hole, but always has a lower entropy. We compare the process to bubble-to-bubble transitions, where there is a semi-classical Lorentzian description in the WKB approximation.

  1. Black hole chemistry: thermodynamics with Lambda

    NASA Astrophysics Data System (ADS)

    Kubizňák, David; Mann, Robert B.; Teo, Mae

    2017-03-01

    We review recent developments on the thermodynamics of black holes in extended phase space, where the cosmological constant is interpreted as thermodynamic pressure and treated as a thermodynamic variable in its own right. In this approach, the mass of the black hole is no longer regarded as internal energy, rather it is identified with the chemical enthalpy. This leads to an extended dictionary for black hole thermodynamic quantities; in particular a notion of thermodynamic volume emerges for a given black hole spacetime. This volume is conjectured to satisfy the reverse isoperimetric inequality—an inequality imposing a bound on the amount of entropy black hole can carry for a fixed thermodynamic volume. New thermodynamic phase transitions naturally emerge from these identifications. Namely, we show that black holes can be understood from the viewpoint of chemistry, in terms of concepts such as Van der Waals fluids, reentrant phase transitions, and triple points. We also review the recent attempts at extending the AdS/CFT dictionary in this setting, discuss the connections with horizon thermodynamics, applications to Lifshitz spacetimes, and outline possible future directions in this field.

  2. Black holes in full quantum gravity

    NASA Astrophysics Data System (ADS)

    Krasnov, Kirill; Rovelli, Carlo

    2009-12-01

    Quantum black holes have been studied extensively in quantum gravity and string theory, using various semiclassical or background-dependent approaches. We explore the possibility of studying black holes in the full non-perturbative quantum theory, without recurring to semiclassical considerations, and in the context of loop quantum gravity. We propose a definition of a quantum black hole as the collection of the quantum degrees of freedom that do not influence observables at infinity. From this definition, it follows that for an observer at infinity a black hole is described by an SU(2) intertwining operator. The dimension of the Hilbert space of such intertwiners grows exponentially with the horizon area. These considerations shed some light on the physical nature of the microstates contributing to the black hole entropy. In particular, it can be seen that the microstates being counted for the entropy have the interpretation of describing different horizon shapes. The space of black hole microstates described here is related to the one arrived at recently by Engle et al (2009, arXiv:0905.3168) and sometime ago by Smolin (1995, J. Math. Phys. 36 6417), but obtained here directly within the full quantum theory.

  3. Quasar Lifetimes and Black Hole Spins

    NASA Astrophysics Data System (ADS)

    Rafiee, Alireza; Hall, P. B.

    2007-12-01

    Wang et al. (2006) estimated a high average radiative efficiency of 30% to 35% for quasars (actively accreting black holes) at moderate redshift, strongly suggesting that all supermassive black holes are rotating very rapidly. Their method for determining radiative efficiencies has two advantages: it deals with changes in quantities rather than absolutes and it is independent of obscured sources. However, we have investigated the reliability of the assumptions made by Wang et al. and have found that their method is not independent of quasar lifetimes. Nonetheless, given constraints on quasar lifetimes, their method can be used to constrain quasar radiative efficiencies and black hole spins. Conversely, the range of radiative efficiencies possible for the full range of black hole spins can be used to constrain the average lifetimes of quasars (assuming that luminous quasars are not powered by radiatively inefficient accretion flows). We will present interrelated constraints on quasar lifetimes, Eddington ratios and radiative efficiencies (black hole spins) from a statistically complete sample of SDSS quasars with black hole mass estimates from Mg II. PBH and AR are supported in part by NSERC.

  4. Star formation around supermassive black holes.

    PubMed

    Bonnell, I A; Rice, W K M

    2008-08-22

    The presence of young massive stars orbiting on eccentric rings within a few tenths of a parsec of the supermassive black hole in the galactic center is challenging for theories of star formation. The high tidal shear from the black hole should tear apart the molecular clouds that form stars elsewhere in the Galaxy, and transport of stars to the galactic center also appears unlikely during their lifetimes. We conducted numerical simulations of the infall of a giant molecular cloud that interacts with the black hole. The transfer of energy during closest approach allows part of the cloud to become bound to the black hole, forming an eccentric disk that quickly fragments to form stars. Compressional heating due to the black hole raises the temperature of the gas up to several hundred to several thousand kelvin, ensuring that the fragmentation produces relatively high stellar masses. These stars retain the eccentricity of the disk and, for a sufficiently massive initial cloud, produce an extremely top-heavy distribution of stellar masses. This potentially repetitive process may explain the presence of multiple eccentric rings of young stars in the presence of a supermassive black hole.

  5. Binary Black Hole Mergers and Recoil Kicks

    NASA Technical Reports Server (NTRS)

    Centrella, Joan; Baker, J.; Choi, D.; Koppitz, M.; vanMeter, J.; Miller, C.

    2006-01-01

    Recent developments in numerical relativity have made it possible to follow reliably the coalescence of two black holes from near the innermost stable circular orbit to final ringdown. This opens up a wide variety of exciting astrophysical applications of these simulations. Chief among these is the net kick received when two unequal mass or spinning black holes merge. The magnitude of this kick has bearing on the production and growth of supermassive black holes during the epoch of structure formation, and on the retention of black holes in stellar clusters. Here we report the first accurate numerical calculation of this kick, for two nonspinning black holes in a 1.5:1 mass ratio, which is expected based on analytic considerations to give a significant fraction of the maximum possible recoil. We have performed multiple runs with different initial separations, orbital angular momenta, resolutions, extraction radii, and gauges. The full range of our kick speeds is 86-116 kilometers per second, and the most reliable runs give kicks between 86 and 97 kilometers per second. This is intermediate between the estimates from two recent post-Newtonian analyses and suggests that at redshifts z greater than 10, halos with masses less than 10(exp 9) M(sub SUN) will have difficulty retaining coalesced black holes after major mergers.

  6. Evaporation of 2-Dimensional Black Holes

    NASA Astrophysics Data System (ADS)

    Ramazanoglu, Fethi M.

    2011-04-01

    Violation of unitarity in black hole evaporation has been puzzling physicist since the seminal work of Hawking in the seventies. Although there are hopes for a resolution of the problem in a full theory of quantum gravity, it has eluded us so far. Even less ambitious efforts considering only quantum corrections beyond the external field approximation have proven hard to attack in 4 dimensions. All these obstacles directed researchers to investigate the black hole evaporation problem in simpler 2-dimensional models. In this talk, we will present results on a new investigation of one of these models, the 2-dimensional Callan-Giddings-Harvey-Strominger (CGHS) model. Using a combination of analytical and high precision numerical tools, we are able to resolve CGHS black hole evaporation within the mean field approximation all the way to the point where the black hole area vanishes. Our results confirm some of the assumptions of the standard paradigm, and strongly suggest the recovery of unitarity within the full quantum theory. On the other hand, there are several surprising new results, in particular remarkable universal behavior in the evaporation of initially macroscopic black holes. This suggests that information about the collapsing matter that formed the black hole can not be recovered from the evaporation radiation. Though this separation of the questions of information loss and unitarity is peculiar to the 2-dimensional model, insights into the higher dimensional case can still be garnered.

  7. The Radio/X-Ray Correlation and the Unification of Low Power Black Holes

    NASA Astrophysics Data System (ADS)

    Körding, E.; Falcke, H.

    We present a unification scheme for active galactic nuclei (AGN) and black hole X-ray binaries (XRBs) using a symbiotic disk/jet model. Scale invariance and energy conservation are used to derive analytical scaling laws for the emission of a jet and allow us to identify the main parameters of the system: the mass of the central black hole and the accretion rate. The developed model can be used to argue for a unifying view of all weakly accreting black holes: a unification of XRBs and AGN. We classify the zoo of AGN in jet and disk dominated sources and test the unification scheme of weakly accreting sources by establishing a universal radio/X-ray correlation for XRBs and AGN. We briefly discuss jets in highly accreting systems.

  8. Neutrino radiation of the AGN black holes

    NASA Astrophysics Data System (ADS)

    Ter-Kazarian, G.; Shidhani, S.; Sargsyan, L.

    2007-07-01

    In the framework of ‘microscopic’ theory of black holes (J. Phys. Soc. Jpn. Suppl. B 70, 84, 2001; Astrophys. USSR 4, 659, 1996; 35, 335, 1991, 33, 143, 1990, 31, 345, 1989a; Astrophys. Space Sci. 1, 1992; Dokl. Akad. Nauk USSR 309, 97, 1989b), and references therein, we address the ‘pre-radiation time’ (PRT) of neutrinos from black holes, which implies the lapse of time from black hole’s birth till radiation of an extremely high energy neutrinos. For post-PRT lifetime, the black hole no longer holds as a region of spacetime that cannot communicate with the external universe. We study main features of spherical accretion onto central BH and infer a mass accretion rate onto it, and, further, calculate the resulting PRT versus bolometric luminosity due to accretion onto black hole. We estimate the PRTs of AGN black holes, with the well-determined masses and bolometric luminosities, collected from the literature by Woo Jong-Hak and Urry (Astrophys. J. 579, 530, 2002) on which this paper is partially based. The simulations for the black holes of masses M BH ≃(1.1ṡ106 ÷4.2ṡ109) M ⊙ give the values of PRTs varying in the range of about T BH ≃(4.3ṡ105 ÷5.6ṡ1011) yr. The derived PRTs for the 60 AGN black holes are longer than the age of the universe (˜13.7 Gyr) favored today. At present, some of remaining 174 BHs may radiate neutrinos. However, these results would be underestimated if the reservoir of gas for accretion in the galaxy center is quite modest, and no obvious way to feed the BHs with substantial accretion.

  9. THE BLACK HOLE FORMATION PROBABILITY

    SciTech Connect

    Clausen, Drew; Piro, Anthony L.; Ott, Christian D.

    2015-02-01

    A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. We present an initial exploration of the probability that a star will make a BH as a function of its ZAMS mass, P {sub BH}(M {sub ZAMS}). Although we find that it is difficult to derive a unique P {sub BH}(M {sub ZAMS}) using current measurements of both the BH mass distribution and the degree of chemical enrichment by massive stars, we demonstrate how P {sub BH}(M {sub ZAMS}) changes with these various observational and theoretical uncertainties. We anticipate that future studies of Galactic BHs and theoretical studies of core collapse will refine P {sub BH}(M {sub ZAMS}) and argue that this framework is an important new step toward better understanding BH formation. A probabilistic description of BH formation will be useful as input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment.

  10. The Black Hole Formation Probability

    NASA Astrophysics Data System (ADS)

    Clausen, Drew; Piro, Anthony L.; Ott, Christian D.

    2015-02-01

    A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. We present an initial exploration of the probability that a star will make a BH as a function of its ZAMS mass, P BH(M ZAMS). Although we find that it is difficult to derive a unique P BH(M ZAMS) using current measurements of both the BH mass distribution and the degree of chemical enrichment by massive stars, we demonstrate how P BH(M ZAMS) changes with these various observational and theoretical uncertainties. We anticipate that future studies of Galactic BHs and theoretical studies of core collapse will refine P BH(M ZAMS) and argue that this framework is an important new step toward better understanding BH formation. A probabilistic description of BH formation will be useful as input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment.

  11. Imaging Black Hole Magnetic Fields with the Event Horizon Telescope

    NASA Astrophysics Data System (ADS)

    Chael, Andrew; Doeleman, Sheperd; Johnson, Michael D.

    2015-08-01

    The Event Horizon Telescope is a global mm-wavelength Very Long Baseline Interferometry array which, when completed, will achieve a nominal resolution of 20 microarcseconds. Initial observations with three stations have detected Schwarzschild-radius-scale structure around the supermassive black holes in SgrA* and M87. Future, fully polarimetric EHT images of the synchrotron emission near supermassive black holes will reveal fine magnetic field structure, potentially illuminating the role of magnetic fields in driving black hole accretion and the connection between magnetic fields, black hole spin, and relativistic jets. I will review techniques for polarimetric VLBI imaging and present new image reconstruction techniques tailored for polarimetric EHT data. Application to synthetic data from simulations shows that the EHT will be able to image changing magnetic field structure on microarcsecond scales. I will also discuss applications to the variable magnetic fields that could power flares in Sgr A*. Finally, I will present initial results from application of these techniques to data from the 2013 EHT observing run.

  12. Toroidal horizons in binary black hole mergers

    NASA Astrophysics Data System (ADS)

    Bohn, Andy; Kidder, Lawrence E.; Teukolsky, Saul A.

    2016-09-01

    We find the first binary black hole event horizon with a toroidal topology. It has been predicted that generically the event horizons of merging black holes should briefly have a toroidal topology. However, such a phase has never been seen in numerical simulations. Instead, in all previous simulations, the topology of the event horizon transitions directly from two spheres during the inspiral to a single sphere as the black holes merge. We find a coordinate transformation to a foliation of spacelike hypersurfaces that "cut a hole" through the event horizon surface, resulting in a toroidal event horizon, thus reconciling the numerical work with theoretical expectations. The demonstration requires extremely high numerical precision, which is made possible by a new event horizon code described in a companion paper. A torus could potentially provide a mechanism for violating topological censorship. However, these toroidal event horizons satisfy topological censorship by construction, because we can always trivially apply the inverse coordinate transformation to remove the topological feature.

  13. New geometries for black hole horizons

    NASA Astrophysics Data System (ADS)

    Armas, Jay; Blau, Matthias

    2015-07-01

    We construct several classes of worldvolume effective actions for black holes by integrating out spatial sections of the worldvolume geometry of asymptotically flat black branes. This provides a generalisation of the blackfold approach for higher-dimensional black holes and yields a map between different effective theories, which we exploit by obtaining new hydrodynamic and elastic transport coefficients via simple integrations. Using Euclidean minimal surfaces in order to decouple the fluid dynamics on different sections of the worldvolume, we obtain local effective theories for ultraspinning Myers-Perry branes and helicoidal black branes, described in terms of a stress-energy tensor, particle currents and non-trivial boost vectors. We then study in detail and present novel compact and non-compact geometries for black hole horizons in higher-dimensional asymptotically flat space-time. These include doubly-spinning black rings, black helicoids and helicoidal p-branes as well as helicoidal black rings and helicoidal black tori in D ≥ 6.

  14. Black hole based tests of general relativity

    NASA Astrophysics Data System (ADS)

    Yagi, Kent; Stein, Leo C.

    2016-03-01

    General relativity has passed all solar system experiments and neutron star based tests, such as binary pulsar observations, with flying colors. A more exotic arena for testing general relativity is in systems that contain one or more black holes. Black holes are the most compact objects in the Universe, providing probes of the strongest-possible gravitational fields. We are motivated to study strong-field gravity since many theories give large deviations from general relativity only at large field strengths, while recovering the weak-field behavior. In this article, we review how one can probe general relativity and various alternative theories of gravity by using electromagnetic waves from a black hole with an accretion disk, and gravitational waves from black hole binaries. We first review model-independent ways of testing gravity with electromagnetic/gravitational waves from a black hole system. We then focus on selected examples of theories that extend general relativity in rather simple ways. Some important characteristics of general relativity include (but are not limited to) (i) only tensor gravitational degrees of freedom, (ii) the graviton is massless, (iii) no quadratic or higher curvatures in the action, and (iv) the theory is four-dimensional. Altering a characteristic leads to a different extension of general relativity: (i) scalar-tensor theories, (ii) massive gravity theories, (iii) quadratic gravity, and (iv) theories with large extra dimensions. Within each theory, we describe black hole solutions, their properties, and current and projected constraints on each theory using black hole based tests of gravity. We close this review by listing some of the open problems in model-independent tests and within each specific theory.

  15. Rotating black hole solutions with quintessential energy

    NASA Astrophysics Data System (ADS)

    Toshmatov, Bobir; Stuchlík, Zdeněk; Ahmedov, Bobomurat

    2017-02-01

    Quintessential dark energy with density ρ and pressure p is governed by an equation of state of the form p=ωqρ with the quintessential parameter ω_qin (-1;-1/3). We derive the geometry of quintessential rotating black holes, generalizing thus the Kerr spacetimes. Then we study the quintessential rotating black hole spacetimes with the special value of ωq = -2/3 when the resulting formulae are simple and easily tractable. We show that such special spacetimes can exist for the dimensionless quintessential parameter c < 1/6 and determine the critical rotational parameter a0 separating the black hole and naked singularity spacetime in dependence on the quintessential parameter c . For the spacetimes with ωq = -2/3 we give all the black hole characteristics and demonstrate local thermodynamical stability. We present the integrated geodesic equations in separated form and study in details the circular geodetical orbits. We give radii and parameters of the photon circular orbits, marginally bound and marginally stable orbits. We stress that the outer boundary on the existence of circular geodesics, given by the so-called static radius where the gravitational attraction of the black hole is balanced by the cosmic repulsion, does not depend on the dimensionless spin of the rotating black hole, similarly to the case of the Kerr-de Sitter spacetimes with vacuum dark energy. We also give restrictions on the dimensionless parameters c and a of the spacetimes allowing for existence of stable circular geodesics. Finally, using numerical methods we generalize the discussion of the circular geodesics to the black holes with arbitrary quintessential parameter ωq.

  16. A massive binary black hole in 1928 + 738?

    NASA Astrophysics Data System (ADS)

    Roos, Nico; Kaastra, Jelle S.; Hummel, Christian A.

    1993-05-01

    We apply the binary black hole model to explain the wiggles in the milliarcsec radio jet of the superluminal quasar 1928 + 738 (4C 73.18) observed with VLBI at 1.3 cm wavelength by Hummel et al. (1992). The period and amplitude of the wiggles can be explained as due to the orbital motion of a binary black hole with mass of order l0 exp 8 solar masses, mass ratio larger than 0.1, and orbital radius about 10 exp 16 cm. The jet's inclination to the line of sight should be small confirming the standard interpretation of superluminal motion and one-sidedness as due to relativistic motion in a direction close to the line of sight. The small orbital radius suggests that the binary has been losing a significant amount of orbital energy during the last 10 exp 7 yr, possibly by interaction with the matter which is flowing through the active galactic nucleus. The arcsec-scale radio structure provides additional support for a link between activity and binary evolution. If our interpretation of the mass wiggle in this quasar is correct, then many other quasars may contain massive binary black holes as well.

  17. Evolution of an accretion disc in binary black hole systems

    NASA Astrophysics Data System (ADS)

    Kimura, Shigeo S.; Takahashi, Sanemichi Z.; Toma, Kenji

    2017-03-01

    We investigate evolution of an accretion disc in binary black hole (BBH) systems and possible electromagnetic counterparts of the gravitational waves from mergers of BBHs. Perna et al. proposed a novel evolutionary scenario of an accretion disc in BBHs in which a disc eventually becomes 'dead', i.e. the magnetorotational instability (MRI) becomes inactive. In their scenario, the dead disc survives until a few seconds before the merger event. We improve the dead disc model and propose another scenario, taking account of effects of the tidal torque from the companion and the critical ionization degree for MRI activation more carefully. We find that the mass of the dead disc is much lower than that in the Perna's scenario. When the binary separation sufficiently becomes small, the mass inflow induced by the tidal torque reactivates MRI, restarting mass accretion on to the black hole. We also find that this disc 'revival' happens more than thousands of years before the merger. The mass accretion induced by the tidal torque increases as the separation decreases, and a relativistic jet could be launched before the merger. The emissions from these jets are too faint compared to gamma-ray bursts, but detectable if the merger events happen within ≲10 Mpc or if the masses of the black holes are as massive as ∼105 M⊙.

  18. Charged black holes and black hole binaries in Multi-messenger Astronomy

    NASA Astrophysics Data System (ADS)

    Liebling, Steven

    2017-01-01

    The possibility of observing electromagnetic signals from gravitational wave events holds great promise for gravitational wave astronomy. I discuss studies of black holes and black hole binaries in both Einstein-Maxwell and Einstein-Maxwell-Dilaton theories, and their implications for LIGO detections and electromagnetic followups, such as Fermi's report of a coincident followup of GW150914.

  19. Radio Telescope Reveals Secrets of Massive Black Hole

    NASA Astrophysics Data System (ADS)

    2008-04-01

    At the cores of many galaxies, supermassive black holes expel powerful jets of particles at nearly the speed of light. Just how they perform this feat has long been one of the mysteries of astrophysics. The leading theory says the particles are accelerated by tightly-twisted magnetic fields close to the black hole, but confirming that idea required an elusive close-up view of the jet's inner throat. Now, using the unrivaled resolution of the National Radio Astronomy Observatory's Very Long Baseline Array (VLBA), astronomers have watched material winding a corkscrew outward path and behaving exactly as predicted by the theory. Galactic core and jet Artist's conception of region near supermassive black hole where twisted magnetic fields propel and shape jet of particles (Credit: Marscher et al., Wolfgang Steffen, Cosmovision, NRAO/AUI/NSF). Click on image for high-resolution file. Watch Video of Black-Hole-Powered Jet (Credit: Cosmovision, Wolfgang Steffen) Download: NTSC Format (90MB) | PAL Format (90MB) "We have gotten the clearest look yet at the innermost portion of the jet, where the particles actually are accelerated, and everything we see supports the idea that twisted, coiled magnetic fields are propelling the material outward," said Alan Marscher, of Boston University, leader of an international research team. "This is a major advance in our understanding of a remarkable process that occurs throughout the Universe," he added. Marscher's team studied a galaxy called BL Lacertae (BL Lac), some 950 million light-years from Earth. BL Lac is a blazar, the most energetic type of black-hole-powered galactic core. A black hole is a concentration of mass so dense that not even light can escape its gravitational pull. Supermassive black holes in galaxies' cores power jets of particles and intense radiation in similar objects including quasars and Seyfert galaxies. Material pulled inward toward the black hole forms a flattened, rotating disk, called an accretion disk

  20. On the location of the supermassive black hole in CTA 102

    NASA Astrophysics Data System (ADS)

    Fromm, Christian M.; Perucho, Manel; Ros, Eduardo; Savolainen, Tuomas; Zensus, J. Anton

    2015-04-01

    Context. Relativistic jets in active galactic nuclei are one of the most powerful phenomena in the Universe. They form in the surroundings of the supermassive black holes as a by-product of accretion onto the central black hole in active galaxies. The flow in the jets propagates at velocities close to the speed of light. The distance between the first part of the jet that is visible in radio images (core) and the black hole is still a matter of debate. Aims: Only very-long-baseline interferometry observations resolve the innermost compact regions of the radio jet. These observations can access the jet base, and by combining data at different wavelenghts, address the physical parameters of the outflow from its emission. Methods: We have performed an accurate analysis of the frequency-dependent shift of the VLBI core location for a multi-wavelength set of images of the blazar CTA 102 including data from 6 cm down to 3 mm. Results: The measure of the position of the central black hole, with mass ~108.93M⊙, in the blazar CTA 102 reveals a distance of ~8 × 104 gravitational radii to the 86 GHz core, in agreement with similar measures obtained for other blazars and distant radio galaxies, and in contrast with recent results for the case of nearby radio galaxies, which show distances between the black hole and the radio core that can be two orders of magnitude smaller.

  1. Causal extraction of black hole rotational energy by various kinds of electromagnetic fields

    SciTech Connect

    Koide, Shinji; Baba, Tamon

    2014-09-10

    Recent general relativistic magnetohydrodynamics (MHD) simulations have suggested that relativistic jets from active galactic nuclei (AGNs) have been powered by the rotational energy of central black holes. Some mechanisms for extraction of black hole rotational energy have been proposed, like the Penrose process, Blandford-Znajek mechanism, MHD Penrose process, and superradiance. The Blandford-Znajek mechanism is the most promising mechanism for the engines of the relativistic jets from AGNs. However, an intuitive interpretation of this mechanism with causality is not yet clarified, while the Penrose process has a clear interpretation for causal energy extraction from a black hole with negative energy. In this paper, we present a formula to build physical intuition so that in the Blandford-Znajek mechanism, as well as in other electromagnetic processes, negative electromagnetic energy plays an important role in causal extraction of the rotational energy of black holes.

  2. Quantum statistical entropy for Kerr de Sitter black hole

    NASA Astrophysics Data System (ADS)

    Zhang, Li-Chun; Wu, Yue-Qin; Zhao, Ren

    2004-06-01

    Improving the membrane model by which the entropy of the black hole is studied, we study the entropy of the black hole in the non-thermal equilibrium state. To give the problem stated here widespread meaning, we discuss the (n+2)-dimensional de Sitter spacetime. Through discussion, we obtain that the black hole's entropy which contains two horizons (a black hole's horizon and a cosmological horizon) in the non-thermal equilibrium state comprises the entropy corresponding to the black hole's horizon and the entropy corresponding to the cosmological horizon. Furthermore, the entropy of the black hole is a natural property of the black hole. The entropy is irrelevant to the radiation field out of the horizon. This deepens the understanding of the relationship between black hole's entropy and horizon's area. A way to study the bosonic and fermionic entropy of the black hole in high non-thermal equilibrium spacetime is given.

  3. Rotating black hole thermodynamics with a particle probe

    SciTech Connect

    Gwak, Bogeun; Lee, Bum-Hoon

    2011-10-15

    The thermodynamics of Myers-Perry black holes in general dimensions are studied using a particle probe. When undergoing particle absorption, the changes of the entropy and irreducible mass are shown to be dependent on the particle radial momentum. The black hole thermodynamic behaviors are dependent on dimensionality for specific rotations. For a 4-dimensional Kerr black hole, its black hole properties are maintained for any particle absorption. 5-dimensional black holes can avoid a naked ring singularity by absorbing a particle in specific momenta ranges. Black holes over 6 dimensions become ultraspinning black holes through a specific form of particle absorption. The microscopical changes are interpreted in limited cases of Myers-Perry black holes using Kerr/CFT correspondence. We systematically describe the black hole properties changed by particle absorption in all dimensions.

  4. HUBBLE UNCOVERS DUST DISK AROUND A MASSIVE BLACK HOLE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Resembling a gigantic hubcap in space, a 3,700 light-year-diameter dust disk encircles a 300 million solar-mass black hole in the center of the elliptical galaxy NGC 7052. The disk, possibly a remnant of an ancient galaxy collision, will be swallowed up by the black hole in several billion years. Because the front end of the disk eclipses more stars than the back, it appears darker. Also, because dust absorbs blue light more effectively than red light, the disk is redder than the rest of the galaxy (this same phenomenon causes the Sun to appear red when it sets in a smoggy afternoon). This NASA Hubble Space Telescope image was taken with the Wide Field and Planetary Camera 2, in visible light. Details as small as 50 light-years across can be seen. Hubble's Faint Object Spectrograph (replaced by the STIS spectrograph in 1997) was used to observe hydrogen and nitrogen emission lines from gas in the disk. Hubble measurements show that the disk rotates like an enormous carousel, 341,000 miles per hour (155 kilometers per second) at 186 light-years from the center. The rotation velocity provides a direct measure of the gravitational force acting on the gas by the black hole. Though 300 million times the mass of our Sun, the black hole is still only 0.05 per cent of the total mass of the NGC 7052 galaxy. Despite its size, the disk is 100 times less massive than the black hole. Still, it contains enough raw material to make three million sun-like stars. The bright spot in the center of the disk is the combined light of stars that have crowded around the black hole due to its strong gravitational pull. This stellar concentration matches theoretical models linking stellar density to a central black hole's mass. NGC 7052 is a strong source of radio emission and has two oppositely directed `jets' emanating from the nucleus. (The jets are streams of energetic electrons moving in a strong magnetic field and unleashing radio energy). Because the jets in NGC 7052 are not

  5. Chaotic cold accretion on to black holes

    NASA Astrophysics Data System (ADS)

    Gaspari, M.; Ruszkowski, M.; Oh, S. Peng

    2013-07-01

    many systems, such as hot galactic haloes, groups and clusters. In this mode, the black hole can quickly react to the state of the entire host galaxy, leading to efficient self-regulated AGN feedback and the symbiotic Magorrian relation. Chaotic accretion can generate high-velocity clouds, likely leading to strong variations in the AGN luminosity, and the deflection or mass-loading of jets. During phases of overheating, the hot mode becomes the single channel of accretion, though strongly suppressed by turbulence. High-resolution data could determine the current mode of accretion: assuming quiescent feedback, the cold mode results in a quasi-flat-temperature core as opposed to the cuspy profile of the hot mode.

  6. Hamiltonian formalism for Perturbed Black Hole Spacetimes

    NASA Astrophysics Data System (ADS)

    Mihaylov, Deyan; Gair, Jonathan

    2017-01-01

    Present and future gravitational wave observations provide a new mechanism to probe the predictions of general relativity. Observations of extreme mass ratio inspirals with millihertz gravitational wave detectors such as LISA will provide exquisite constraints on the spacetime structure outside astrophysical black holes, enabling tests of the no-hair property that all general relativistic black holes are described by the Kerr metric. Previous work to understand what constraints LISA observations will be able to place has focussed on specific alternative theories of gravity, or generic deviations that preserve geodesic separability. We describe an alternative approach to this problem--a technique that employs canonical perturbations of the Hamiltonian function describing motion in the Kerr metric. We derive this new approach and demonstrate its application to the cases of a slowly rotating Kerr black hole which is viewed as a perturbation of a Schwarzschild black hole, of coupled perturbations of black holes in the second-order Chern-Simons modified gravity theory, and several more indicative scenarios. Deyan Mihaylov is funded by STFC.

  7. Black holes in the early Universe.

    PubMed

    Volonteri, Marta; Bellovary, Jillian

    2012-12-01

    The existence of massive black holes (MBHs) was postulated in the 1960s, when the first quasars were discovered. In the late 1990s their reality was proven beyond doubt in the Milky way and a handful nearby galaxies. Since then, enormous theoretical and observational efforts have been made to understand the astrophysics of MBHs. We have discovered that some of the most massive black holes known, weighing billions of solar masses, powered luminous quasars within the first billion years of the Universe. The first MBHs must therefore have formed around the time the first stars and galaxies formed. Dynamical evidence also indicates that black holes with masses of millions to billions of solar masses ordinarily dwell in the centers of today's galaxies. MBHs populate galaxy centers today, and shone as quasars in the past; the quiescent black holes that we detect now in nearby bulges are the dormant remnants of this fiery past. In this review we report on basic, but critical, questions regarding the cosmological significance of MBHs. What physical mechanisms led to the formation of the first MBHs? How massive were the initial MBH seeds? When and where did they form? How is the growth of black holes linked to that of their host galaxy? The answers to most of these questions are works in progress, in the spirit of these reports on progress in physics.

  8. Kerr black holes as retro-MACHOs

    NASA Astrophysics Data System (ADS)

    De Paolis, F.; Geralico, A.; Ingrosso, G.; Nucita, A. A.; Qadir, A.

    2004-02-01

    Gravitational lensing is a well known phenomenon predicted by the General Theory of Relativity. It is now a well-developed observational technique in astronomy and is considered to be a fundamental tool for acquiring information about the nature and distribution of dark matter. In particular, gravitational lensing experiments may be used to search for black holes. It has been proposed that a Schwarzschild black hole may act as a retro-lens (Holz & Wheeler \\cite{hw}) which, if illuminated by a powerful light source (e.g. the Sun), deflects light ray paths to large bending angles so that the light may reach the observer. Here, by considering the strong field limit in the deflection angle and confining our analysis to the black hole equatorial plane, we extend the Holz-Wheeler results to slowly spinning Kerr black holes. By considering the Holz-Wheeler geometrical configuration for the lens, source and observer we find that the inclusion of rotation does not substantially change the brightness of the retro-lensing images with respect to the Schwarzschild case. We also discuss the possibility that the next generation space-based telescopes may detect such retro-images and eventually put limits on the rotational parameter of the black hole.

  9. Nonthermal WIMPs and primordial black holes

    NASA Astrophysics Data System (ADS)

    Georg, Julian; Şengör, Gizem; Watson, Scott

    2016-06-01

    Nonthermal histories for the early universe have received notable attention as they are a rich source of phenomenology, while also being well motivated by top-down approaches to beyond the Standard Model physics. The early (pre-big bang nucleosynthesis) matter phase in these models leads to enhanced growth of density perturbations on sub-Hubble scales. Here, we consider whether primordial black hole formation associated with the enhanced growth is in conflict with existing observations. Such constraints depend on the tilt of the primordial power spectrum, and we find that nonthermal histories are tightly constrained in the case of a significantly blue spectrum. Alternatively, if dark matter is taken to be of nonthermal origin, we can restrict the primordial power spectrum on scales inaccessible to cosmic microwave background and large scale structure observations. We establish constraints for a wide range of scalar masses (reheat temperatures) with the most stringent bounds resulting from the formation of 1015 g black holes. These black holes would be evaporating today and are constrained by FERMI observations. We also consider whether the breakdown of the coherence of the scalar oscillations on subhorizon scales can lead to a Jean's pressure preventing black hole formation and relaxing our constraints. Our main conclusion is that primordial black hole constraints, combined with existing constraints on nonthermal weakly interacting massive particles, favor a primordial spectrum closer to scale invariance or a red tilted spectrum.

  10. The Environmental Impact of Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Loeb, A.

    The supermassive black holes observed at the centers of almost all present-day galaxies had a profound impact on their environment. I highlight the principle of self-regulation, by which supermassive black holes grow until they release sufficient energy to unbind the gas that feeds them from their host galaxy. This principle explains several observed facts, including the correlation between the mass of a central black hole and the depth of the gravitational potential well of its host galaxy, and the abundance and clustering properties of bright quasars in the redshift interval of z~ 2-6. At lower redshifts, quasars might have limited the maximum mass of galaxies through the suppression of cooling flows in X-ray clusters. The seeds of supermassive black holes were likely planted in dwarf galaxies at redshifts z> 10, through the collapse of massive or supermassive stars. The minimum seed mass can be identified observationally through the detection of gravitational waves from black hole binaries by Advanced LIGO or LISA. Aside from shaping their host galaxies, quasar outflows filled the intergalactic medium with magnetic fields and heavy elements. Beyond the reach of these outflows, the brightest quasars at z>6 have ionized exceedingly large volumes of gas (tens of comoving Mpc) prior to global reionization, and must have suppressed the faint end of the galaxy luminosity function in these volumes before the same occurred through the rest of the universe.

  11. A black hole in a globular cluster.

    PubMed

    Maccarone, Thomas J; Kundu, Arunav; Zepf, Stephen E; Rhode, Katherine L

    2007-01-11

    Globular star clusters contain thousands to millions of old stars packed within a region only tens of light years across. Their high stellar densities make it very probable that their member stars will interact or collide. There has accordingly been considerable debate about whether black holes should exist in these star clusters. Some theoretical work suggests that dynamical processes in the densest inner regions of globular clusters may lead to the formation of black holes of approximately 1,000 solar masses. Other numerical simulations instead predict that stellar interactions will eject most or all of the black holes that form in globular clusters. Here we report the X-ray signature of an accreting black hole in a globular cluster associated with the giant elliptical galaxy NGC 4472 (in the Virgo cluster). This object has an X-ray luminosity of about 4 x 10(39) erg s(-1), which rules out any object other than a black hole in such an old stellar population. The X-ray luminosity varies by a factor of seven in a few hours, which excludes the possibility that the object is several neutron stars superposed.

  12. Black Hole Hunters Set New Distance Record

    NASA Astrophysics Data System (ADS)

    2010-01-01

    Astronomers using ESO's Very Large Telescope have detected, in another galaxy, a stellar-mass black hole much farther away than any other previously known. With a mass above fifteen times that of the Sun, this is also the second most massive stellar-mass black hole ever found. It is entwined with a star that will soon become a black hole itself. The stellar-mass black holes [1] found in the Milky Way weigh up to ten times the mass of the Sun and are certainly not be taken lightly, but, outside our own galaxy, they may just be minor-league players, since astronomers have found another black hole with a mass over fifteen times the mass of the Sun. This is one of only three such objects found so far. The newly announced black hole lies in a spiral galaxy called NGC 300, six million light-years from Earth. "This is the most distant stellar-mass black hole ever weighed, and it's the first one we've seen outside our own galactic neighbourhood, the Local Group," says Paul Crowther, Professor of Astrophysics at the University of Sheffield and lead author of the paper reporting the study. The black hole's curious partner is a Wolf-Rayet star, which also has a mass of about twenty times as much as the Sun. Wolf-Rayet stars are near the end of their lives and expel most of their outer layers into their surroundings before exploding as supernovae, with their cores imploding to form black holes. In 2007, an X-ray instrument aboard NASA's Swift observatory scrutinised the surroundings of the brightest X-ray source in NGC 300 discovered earlier with the European Space Agency's XMM-Newton X-ray observatory. "We recorded periodic, extremely intense X-ray emission, a clue that a black hole might be lurking in the area," explains team member Stefania Carpano from ESA. Thanks to new observations performed with the FORS2 instrument mounted on ESO's Very Large Telescope, astronomers have confirmed their earlier hunch. The new data show that the black hole and the Wolf-Rayet star dance

  13. Balloon-Borne Gamma-Ray Polarimeter (PoGO) to Study Black Holes, Pulsars, and AGN Jets: Design and Calibration(SULI)

    SciTech Connect

    Apte, Zachary; /Hampshire Coll. /SLAC

    2005-12-15

    Polarization measurements at X-ray and gamma-ray energies can provide crucial information on the emission region around massive compact objects such as black holes and neutron stars. The Polarized Gamma-ray Observer (PoGO) is a new balloon-borne instrument designed to measure polarization from such astrophysical objects in the 30-100 keV range, under development by an international collaboration with members from United States, Japan, Sweden and France. The PoGO instrument has been designed by the collaboration and several versions of prototype models have been built at SLAC. The purpose of this experiment is to test the latest prototype model with a radioactive gamma-ray source. For this, we have to polarize gamma-rays in a laboratory environment. Unpolarized gamma-rays from Am241 (59.5 keV) were Compton scattered at around 90 degrees for this purpose. Computer simulation of the scattering process in the setup predicts a 86% polarization. The polarized beam was then used to irradiate the prototype PoGO detector. The data taken in this experiment showed a clear polarization signal, with a measured azimuthal modulation factor of 0.35 {+-} 0.02. The measured modulation is in very close agreement with the value expected from a previous beam test study of a polarized gamma-ray beam at the Argonne National Laboratories Advanced Photon Source. This experiment has demonstrated that the PoGO instrument (or any other polarimeter in the energy range) can be tested in a libratory with a simple setup to a similar accuracy.

  14. Black Hole Boldly Goes Where No Black Hole Has Gone Before

    NASA Astrophysics Data System (ADS)

    2007-01-01

    Astronomers have found a black hole where few thought they could ever exist, inside a globular star cluster. The finding has broad implications for the dynamics of stars clusters and also for the existence of a still-speculative new class of black holes called 'intermediate-mass' black holes. The discovery is reported in the current issue of Nature. Tom Maccarone of the University of Southampton in England leads an international team on the finding, made primarily with the European Space Agency's XMM-Newton satellite. Globular clusters are dense bundles of thousands to millions of old stars, and many scientists have doubted that black holes could survive in such an exclusive environment. Computer simulations show that a newly formed black hole would first sink towards the centre of the cluster but quickly get gravitationally slingshot out entirely when interacting with the cluster's myriad stars. Credit: ESA/Hubble Artist's impression of globular star cluster The new finding provides the first convincing evidence that some black hole might not only survive but grow and flourish in globular clusters. What has astonished astronomers is how quickly the black hole was found. "We were preparing for a long, systematic search of thousands of globular clusters with the hope of finding just one black hole," said Maccarone. "But bingo, we found one as soon as we started the search. It was only the second globular cluster we looked at." The search continues to find more, Maccarone said, yet only one black hole was needed to resolve the decades-old discussion about black holes and globular clusters. Scientists say there are two main classes of black holes. Supermassive black holes containing the mass of millions to billions of suns are found in the core of most galaxies, including our own. A quasar is one kind of supermassive black hole. Stellar-size black holes contain the mass of about ten suns. These are created from the collapsed core of massive stars. Our galaxy likely

  15. Can Direct Collapse Black Holes Launch Gamma-Ray Bursts and Grow to Supermassive Black Holes?

    NASA Astrophysics Data System (ADS)

    Matsumoto, Tatsuya; Nakauchi, Daisuke; Ioka, Kunihito; Heger, Alexander; Nakamura, Takashi

    2015-09-01

    The existence of black holes (BHs) of mass ˜ {10}9 {M}⊙ at z≳ 6 is a big puzzle in astrophysics because even optimistic estimates of the accretion time are insufficient for stellar-mass BHs of ˜ 10 {M}⊙ to grow into such supermassive BHs. A resolution of this puzzle might be the direct collapse of supermassive stars with mass M˜ {10}5 {M}⊙ into massive seed BHs. We find that if a jet is launched from the accretion disk around the central BH, the jet can break out of the star because of the structure of the radiation-pressure-dominated envelope. Such ultralong gamma-ray bursts with duration of ˜ {10}4-106 s and flux of 10-11-10-8 erg s-1 cm-2 could be detectable by Swift. We estimate an event rate of ≲ 1 {{yr}}-1. The total explosion energy is ≳1055-{10}56 {erg}. The resulting negative feedback delays the growth of the remnant BH by about 70 {Myr} or evacuates the host galaxy completely.

  16. Upper bound on the radii of black-hole photonspheres

    NASA Astrophysics Data System (ADS)

    Hod, Shahar

    2013-11-01

    One of the most remarkable predictions of the general theory of relativity is the existence of black-hole “photonspheres”, compact null hypersurfaces on which massless particles can orbit the central black hole. We prove that every spherically-symmetric asymptotically flat black-hole spacetime is characterized by a photonsphere whose radius is bounded from above by rγ⩽3M, where M is the total ADM mass of the black-hole spacetime. It is shown that hairy black-hole configurations conform to this upper bound. In particular, the null circular geodesic of the (bald) Schwarzschild black-hole spacetime saturates the bound.

  17. Thick domain walls in AdS black hole spacetimes

    SciTech Connect

    Moderski, Rafal; Rogatko, Marek

    2006-08-15

    Equations of motion for a real self-gravitating scalar field in the background of a black hole with negative cosmological constant were solved numerically. We obtain a sequence of static axisymmetric solutions representing thick domain wall cosmological black hole systems, depending on the mass of black hole, cosmological parameter and the parameter binding black hole mass with the width of the domain wall. For the case of extremal cosmological black hole the expulsion of scalar field from the black hole strongly depends on it.

  18. Massive Black Hole Implicated in Stellar Destruction

    NASA Astrophysics Data System (ADS)

    2010-01-01

    New results from NASA's Chandra X-ray Observatory and the Magellan telescopes suggest that a dense stellar remnant has been ripped apart by a black hole a thousand times as massive as the Sun. If confirmed, this discovery would be a cosmic double play: it would be strong evidence for an intermediate mass black hole, which has been a hotly debated topic, and would mark the first time such a black hole has been caught tearing a star apart. This scenario is based on Chandra observations, which revealed an unusually luminous source of X-rays in a dense cluster of old stars, and optical observations that showed a peculiar mix of elements associated with the X-ray emission. Taken together, a case can be made that the X-ray emission is produced by debris from a disrupted white dwarf star that is heated as it falls towards a massive black hole. The optical emission comes from debris further out that is illuminated by these X-rays. The intensity of the X-ray emission places the source in the "ultraluminous X-ray source" or ULX category, meaning that it is more luminous than any known stellar X-ray source, but less luminous than the bright X-ray sources (active galactic nuclei) associated with supermassive black holes in the nuclei of galaxies. The nature of ULXs is a mystery, but one suggestion is that some ULXs are black holes with masses between about a hundred and several thousand times that of the Sun, a range intermediate between stellar-mass black holes and supermassive black holes located in the nuclei of galaxies. This ULX is in a globular cluster, a very old and crowded conglomeration of stars. Astronomers have suspected that globular clusters could contain intermediate-mass black holes, but conclusive evidence for this has been elusive. "Astronomers have made cases for stars being torn apart by supermassive black holes in the centers of galaxies before, but this is the first good evidence for such an event in a globular cluster," said Jimmy Irwin of the University

  19. Black hole complementarity in gravity's rainbow

    SciTech Connect

    Gim, Yongwan; Kim, Wontae E-mail: wtkim@sogang.ac.kr

    2015-05-01

    To see how the gravity's rainbow works for black hole complementary, we evaluate the required energy for duplication of information in the context of black hole complementarity by calculating the critical value of the rainbow parameter in the certain class of the rainbow Schwarzschild black hole. The resultant energy can be written as the well-defined limit for the vanishing rainbow parameter which characterizes the deformation of the relativistic dispersion relation in the freely falling frame. It shows that the duplication of information in quantum mechanics could not be allowed below a certain critical value of the rainbow parameter; however, it might be possible above the critical value of the rainbow parameter, so that the consistent formulation in our model requires additional constraints or any other resolutions for the latter case.

  20. Gravitational lens models for cosmological black holes

    NASA Astrophysics Data System (ADS)

    Zakharov, A. F.; Capozziello, S.; Stornaiolo, C.

    2017-03-01

    If really such objects like cosmological black holes exist they may be studied with a standard technique like strong and weak gravitational lensing. Cosmological voids can be explained as the result the collapse of large perturbations into black hole with masses of the order of 1014 M ⊙ and the expansion of the universe. The resulting image of the universe is that it is more homogeneous than expected from present observations. In this paper we discuss some lensing properties related to the cosmological black holes (CBHs), namely we consider differences in gravitational lensing for point like mass and extended mass distributions. We consider the singular isothermal sphere model as a toy (illustrative) model for an extended distribution of dark matter and a slightly more complicated isothermal sphere with a core.

  1. Bounded excursion stable gravastars and black holes

    SciTech Connect

    Rocha, P; Da Silva, M F; Wang, Anzhong; Santos, N O E-mail: yasuda@on.br E-mail: mfasnic@gmail.com E-mail: anzhong_wang@baylor.edu

    2008-06-15

    Dynamical models of prototype gravastars were constructed in order to study their stability. The models are the Visser-Wiltshire three-layer gravastars, in which an infinitely thin spherical shell of stiff fluid divides the whole spacetime into two regions, where the internal region is de Sitter, and the external one is Schwarzschild. It is found that in some cases the models represent the 'bounded excursion' stable gravastars, where the thin shell is oscillating between two finite radii, while in other cases they collapse until the formation of black holes occurs. In the phase space, the region for the 'bounded excursion' gravastars is very small in comparison to that of black holes, but not empty. Therefore, although the possibility of the existence of gravastars cannot be excluded from such dynamical models, our results indicate that, even if gravastars do indeed exist, that does not exclude the possibility of the existence of black holes.

  2. Accretion Disk Emission Around Kerr Black Holes

    NASA Astrophysics Data System (ADS)

    Campitiello, Samuele; Sbarrato, T.; Ghisellini, G.

    2016-10-01

    Measuring the spin of supermassive Black holes in Active Galactic Nuclei is a further step towards a better understanding of the evolution of their physics. We proposed a new method to estimate the Black hole spin, based on data-fitting. We consider a numerical model called KERRBB, including all relativistic effects (i.e. light-bending, gravitational redshift and Doppler beaming). We found that the same spectrum can be produced by different masses, accretion rates and spins, but that these three quantities are related. In other words, having a robust indipendent estimate on one of these three quantities fixes the other two. By using the Black hole mass, estimated by the virial method, we can pinpoint a narrow range of possible spins and accretion rates for the 32 blazars we have studied. For these objects, we found a lower limit of the spin, that must be a/M > 0.6-0.7

  3. Thermodynamics of higher dimensional black holes

    SciTech Connect

    Accetta, F.S.; Gleiser, M.

    1986-05-01

    We discuss the thermodynamics of higher dimensional black holes with particular emphasis on a new class of spinning black holes which, due to the increased number of Casimir invariants, have additional spin degrees of freedom. In suitable limits, analytic solutions in arbitrary dimensions are presented for their temperature, entropy, and specific heat. In 5 + 1 and 9 + 1 dimensions, more general forms for these quantities are given. It is shown that the specific heat for a higher dimensional black hole is negative definite if it has only one non-zero spin parameter, regardless of the value of this parameter. We also consider equilibrium configurations with both massless particles and massive string modes. 16 refs., 3 figs.

  4. Supersymmetry Versus Black Holes at the Lhc

    NASA Astrophysics Data System (ADS)

    Roy, Arunava; Cavaglià, Marco

    Supersymmetry and extra dimensions are the two most promising candidates for new physics at the TeV scale. Supersymmetric particles or extra-dimensional effects could soon be observed at the Large Hadron Collider. We propose a simple but effective method to discriminate the two models: the analysis of isolated leptons with high transverse momentum. Black hole events are simulated with the CATFISH black hole generator. Supersymmetry simulations use a combination of PYTHIA and ISAJET, the latter providing the mass spectrum. Our results show that the measure of the dilepton invariant mass provides a promising signature to differentiate supersymmetry and black hole events at the Large Hadron Collider. Analysis of event-shape variables and multilepton events complement and strengthen this conclusion.

  5. Black hole mergers: beyond general relativity

    NASA Astrophysics Data System (ADS)

    Stein, Leo; Okounkova, Maria

    2017-01-01

    One hundred years after the birth of general relativity, advanced LIGO has finally directly detected gravitational waves. The source: two black holes merging into one. Advanced LIGO will soon provide the opportunity to test GR, using gravitational waves, in the dynamical strong-field regime-a setting where GR has not yet been tested. GR has passed all weak-field tests with flying colors. Yet it should eventually break down, so we must look to the strong-field. To perform strong-field tests of GR, we need waveform models from theories beyond GR. To date there are no numerical simulations of black hole mergers in theories which differ from GR. The main obstacle is the mathematical one of well-posedness. I will explain how to overcome this obstacle, and demonstrate the success of this approach by presenting the first numerical simulations of black hole mergers in a theory beyond GR.

  6. Primordial Black Holes from First Principles (numerics)

    NASA Astrophysics Data System (ADS)

    Bloomfield, Jolyon; Moss, Zander; Lam, Casey; Russell, Megan; Face, Stephen; Guth, Alan

    2017-01-01

    In order to compute accurate number densities and mass spectra for primordial black holes from an inflationary power spectrum, one needs to perform Monte Carlo integration over field configurations. This requires a method of determining whether a black hole will form, and if so, what its mass will be, for each sampled configuration. In order for such an integral to converge within any reasonable time, this requires a highly efficient process for making these determinations. We present a numerical pipeline that is capable of making reasonably accurate predictions for black holes and masses at the rate of a few seconds per sample (including the sampling process), utilizing a fully-nonlinear numerical relativity code in 1+1 dimensions.

  7. Thermodynamics of regular accelerating black holes

    NASA Astrophysics Data System (ADS)

    Astorino, Marco

    2017-03-01

    Using the covariant phase space formalism, we compute the conserved charges for a solution, describing an accelerating and electrically charged Reissner-Nordstrom black hole. The metric is regular provided that the acceleration is driven by an external electric field, in spite of the usual string of the standard C-metric. The Smarr formula and the first law of black hole thermodynamics are fulfilled. The resulting mass has the same form of the Christodoulou-Ruffini irreducible mass. On the basis of these results, we can extrapolate the mass and thermodynamics of the rotating C-metric, which describes a Kerr-Newman-(A)dS black hole accelerated by a pulling string.

  8. Black Holes in a Violent Universe

    NASA Astrophysics Data System (ADS)

    Britzen, S.

    2012-02-01

    "Black Holes in a Violent Universe" is a COST Action (MP0905) connecting scientists from different disciplines - astronomers from all wavelength regimes (i.e. radio to TeV), physicists and particle physicists, theoreticians and observers - from currently 25 countries. The aim is to collaborate in a cross-disciplinary and multi-dimensional approach towards a better understanding of the general Black Hole phenomenon. COST (European Cooperation in Science and Technology) is one of the longest-running European instruments supporting cooperation among scientists and researchers across Europe. The goal of MP0905 is to decipher further the way the Universe and the stars and galaxies evolved and - in particular - the role Black Holes play in this. This Action is an open and flexible program of communication and interchange.

  9. Regular black holes with flux tube core

    SciTech Connect

    Zaslavskii, Oleg B.

    2009-09-15

    We consider a class of black holes for which the area of the two-dimensional spatial cross section has a minimum on the horizon with respect to a quasiglobal (Krusckal-like) coordinate. If the horizon is regular, one can generate a tubelike counterpart of such a metric and smoothly glue it to a black hole region. The resulting composite space-time is globally regular, so all potential singularities under the horizon of the original metrics are removed. Such a space-time represents a black hole without an apparent horizon. It is essential that the matter should be nonvacuum in the outer region but vacuumlike in the inner one. As an example we consider the noninteracting mixture of vacuum fluid and matter with a linear equation of state and scalar phantom fields. This approach is extended to distorted metrics, with the requirement of spherical symmetry relaxed.

  10. How to Build a Supermassive Black Hole

    NASA Technical Reports Server (NTRS)

    Wanjek, Christopher

    2003-01-01

    NASA astronomer Kim Weaver has got that sinking feeling. You know, it's that unsettling notion you get when you sift through your X-ray data and, to your surprise, find mid-sized black holes sinking toward the center of a galaxy, where they merge with others to form a single supermassive black hole. Could such a thing be true? These would be the largest mergers since America On Line bought Time-Warner, and perhaps even more violent. The process would turn a starburst galaxy inside out, making it more like a quasar host galaxy. Using the Chandra X-Ray Observatory, Weaver saw a hint of this fantastic process in a relatively nearby starburst galaxy named NGC 253 in the constellation Sculptor. She noticed that starburst galaxies - those gems set aglow in a colorful life cycle of hyperactive star birth, death, and renewal - seem to have a higher concentration of mid-mass black holes compared to other galaxies.

  11. Observational constraints on black hole accretion disks

    NASA Technical Reports Server (NTRS)

    Liang, Edison P.

    1994-01-01

    We review the empirical constraints on accretion disk models of stellar-mass black holes based on recent multiwavelength observational results. In addition to time-averaged emission spectra, the time evolutions of the intensity and spectrum provide critical information about the structure, stability, and dynamics of the disk. Using the basic thermal Keplerian disk paradigm, we consider in particular generalizations of the standard optically thin disk models needed to accommodate the extremely rich variety of dynamical phenomena exhibited by black hole candidates ranging from flares of electron-positron annihilations and quasiperiodic oscillations in the X-ray intensity to X-ray novae activity. These in turn provide probes of the disk structure and global geometry. The goal is to construct a single unified framework to interpret a large variety of black hole phenomena. This paper will concentrate on the interface between basic theory and observational data modeling.

  12. Black holes in an expanding universe.

    PubMed

    Gibbons, Gary W; Maeda, Kei-ichi

    2010-04-02

    An exact solution representing black holes in an expanding universe is found. The black holes are maximally charged and the universe is expanding with arbitrary equation of state (P = w rho with -1 < or = for all w < or = 1). It is an exact solution of the Einstein-scalar-Maxwell system, in which we have two Maxwell-type U(1) fields coupled to the scalar field. The potential of the scalar field is an exponential. We find a regular horizon, which depends on one parameter [the ratio of the energy density of U(1) fields to that of the scalar field]. The horizon is static because of the balance on the horizon between gravitational attractive force and U(1) repulsive force acting on the scalar field. We also calculate the black hole temperature.

  13. Hologram of a pure state black hole

    NASA Astrophysics Data System (ADS)

    Roy, Shubho R.; Sarkar, Debajyoti

    2015-12-01

    In this paper, we extend the Hamilton-Kabat-Lifschytz-Lowe (HKLL) holographic smearing function method to reconstruct (quasi)local anti-de Sitter bulk scalar observables in the background of a large anti-de Sitter black hole formed by null shell collapse (a "pure state" black hole), from the dual conformal field theory which is undergoing a sudden quench. In particular, we probe the near horizon and subhorizon bulk locality. First, we construct local bulk operators from the conformal field theory in the leading semiclassical limit, N →∞ . Then, we look at effects due to the finiteness of N , where we propose a suitable coarse-graining prescription involving early and late time cutoffs to define semiclassical bulk observables which are approximately local, their departure from locality being nonperturbatively small in N . Our results have important implications on the black hole information problem.

  14. Twisted black hole is Taub-NUT

    NASA Astrophysics Data System (ADS)

    Ong, Yen Chin

    2017-01-01

    Recently a purportedly novel solution of the vacuum Einstein field equations was discovered: it supposedly describes an asymptotically flat twisted black hole in 4-dimensions whose exterior spacetime rotates in a peculiar manner—the frame dragging in the northern hemisphere is opposite from that of the southern hemisphere, which results in a globally vanishing angular momentum. Furthermore it was shown that the spacetime has no curvature singularity. We show that the geometry of this black hole spacetime is nevertheless not free of pathological features. In particular, it harbors a rather drastic conical singularity along the axis of rotation. In addition, there exist closed timelike curves due to the fact that the constant r and constant t surfaces are not globally Riemannian. In fact, none of these are that surprising since the solution is just the Taub-NUT geometry. As such, despite the original claim that the twisted black hole might have observational consequences, it cannot be.

  15. Black holes and quantumness on macroscopic scales

    NASA Astrophysics Data System (ADS)

    Flassig, Daniel; Pritzel, Alexander; Wintergerst, Nico

    2013-04-01

    It has recently been suggested that black holes may be described as condensates of weakly interacting gravitons at a critical point, exhibiting strong quantum effects. In this paper, we study a model system of attractive bosons in one spatial dimension which is known to undergo a quantum phase transition. We demonstrate explicitly that indeed quantum effects are important at the critical point, even if the number of particles is macroscopic. Most prominently, we evaluate the entropy of entanglement between different momentum modes and observe it to become maximal at the critical point. Furthermore, we explicitly see that the leading entanglement is between long-wavelength modes and is hence a feature independent of ultraviolet physics. If applicable to black holes, our findings substantiate the conjectured breakdown of semiclassical physics even for large black holes. This can resolve long-standing mysteries, such as the information paradox and the no-hair theorem.

  16. Black holes and large order quantum geometry

    SciTech Connect

    Huang Minxin; Klemm, Albrecht; Marino, Marcos; Tavanfar, Alireza

    2009-03-15

    We study five-dimensional black holes obtained by compactifying M theory on Calabi-Yau threefolds. Recent progress in solving topological string theory on compact, one-parameter models allows us to test numerically various conjectures about these black holes. We give convincing evidence that a microscopic description based on Gopakumar-Vafa invariants accounts correctly for their macroscopic entropy, and we check that highly nontrivial cancellations--which seem necessary to resolve the so-called entropy enigma in the Ooguri-Strominger-Vafa conjecture--do in fact occur. We also study analytically small 5d black holes obtained by wrapping M2 branes in the fiber of K3 fibrations. By using heterotic/type II duality we obtain exact formulae for the microscopic degeneracies in various geometries, and we compute their asymptotic expansion for large charges.

  17. Nonlinear electrodynamics and regular black holes

    NASA Astrophysics Data System (ADS)

    Sajadi, S. N.; Riazi, N.

    2017-03-01

    In this work, an exact regular black hole solution in General Relativity is presented. The source is a nonlinear electromagnetic field with the algebraic structure T00=T11 for the energy-momentum tensor, partially satisfying the weak energy condition but not the strong energy condition. In the weak field limit, the EM field behaves like the Maxwell field. The solution corresponds to a charged black hole with q≤0.77 m. The metric, the curvature invariants, and the electric field are regular everywhere. The BH is stable against small perturbations of spacetime and using the Weinhold metric, geometrothermodynamical stability has been investigated. Finally we investigate the idea that the observable universe lives inside a regular black hole. We argue that this picture might provide a viable description of universe.

  18. Status Report: Black Hole Complementarity Controversy

    NASA Astrophysics Data System (ADS)

    Lee, Bum-Hoon; Yeom, Dong-han

    2014-01-01

    Black hole complementarity was a consensus among string theorists for the interpretation of the information loss problem. However, recently some authors find inconsistency of black hole complementarity: large N rescaling and Almheiri, Marolf, Polchinski and Sully (AMPS) argument. According to AMPS, the horizon should be a firewall so that one cannot penetrate there for consistency. There are some controversial discussions on the firewall. Apart from these papers, the authors suggest an assertion using a semi-regular black hole model and we conclude that the firewall, if it exists, should affect to asymptotic observer. In addition, if any opinion does not consider the duplication experiment and the large N rescaling, then the argument is difficult to accept.

  19. High-energy signatures of binary systems of supermassive black holes

    NASA Astrophysics Data System (ADS)

    Romero, G. E.; Vila, G. S.; Pérez, D.

    2016-04-01

    Context. Binary systems of supermassive black holes are expected to be strong sources of long gravitational waves prior to merging. These systems are good candidates to be observed with forthcoming space-borne detectors. Only a few of these systems, however, have been firmly identified to date. Aims: We aim at providing a criterion for the identification of some supermassive black hole binaries based on the characteristics of the high-energy emission of a putative relativistic jet launched from the most massive of the two black holes. Methods: We study supermassive black hole binaries where the less massive black hole has carved an annular gap in the circumbinary disk, but nevertheless there is a steady mass flow across its orbit. Such a perturbed disk is hotter and more luminous than a standard thin disk in some regions. Assuming that the jet contains relativistic electrons, we calculate its broadband spectral energy distribution focusing on the inverse Compton up-scattering of the disk photons. We also compute the opacity to the gamma rays produced in the jet by photon annihilation with the disk radiation and take into account the effects of the anisotropy of the target photon field as seen from the jet. Results: We find that the excess of low-energy photons radiated by the perturbed disk causes an increment in the external Compton emission from the jet in the X-ray band, and a deep absorption feature at energies of tens of TeVs for some sets of parameters. According to our results, observations with Cherenkov telescopes might help in the identification of supermassive black hole binaries, especially those black hole binaries that host primaries from tens to hundreds of million of solar masses.

  20. Quasar Outflows and Black Hole Masses

    NASA Astrophysics Data System (ADS)

    Coatman, Liam; Hewett, Paul; Banerji, Manda; Richards, Gordon; Hennawi, Joseph; Prochaska, Jason X.

    2016-08-01

    Black-hole masses are crucial to understanding the physics of the connection between quasars and their host galaxies and measuring cosmic black hole-growth. At high redshift, z > 2, black hole masses are normally derived using the velocity-width of the CIV broad emission line, based on the assumption that the observed velocity-widths arise from virial-induced motions. In many quasars, the CIV-emission line exhibits significant blue asymmetries ('blueshifts') with the line centroid displaced by up to thousands of km/s to the blue. These blueshifts almost certainly signal the presence of strong outflows, most likely originating in a disc wind. Using both archival data and new observations, we have obtained near-infrared spectra, including the Ha and/or Hb emission lines, for ~400 luminous (L_Bol = 45.5-48.5 erg/s) SDSS quasars, at redshifts 1.5 < z < 4, with CIV emission lines spanning the full-range of blueshifts present in the population. A strong correlation between CIV-velocity width and blueshift is found and, at large blueshifts, >2000 km/s, the velocity-widths appear to be dominated by non-virial motions. Using the Ha/Hb emission to provide black hole masses free from non-virial contributions, we are able to derive a quantitative correction to the CIV-based black-hole masses as a function of blueshift. This correction reduces the scatter between Ha/Hb and CIV velocity widths to just ~0.1 dex. Without the correction, black hole masses would be overestimated by a factor of nine at the largest blueshifts. With a suitable systemic redshift-estimation algorithm, this correction can be straightforwardly applied based only on information contained in the rest-frame UV spectra.

  1. Rotating black holes on codimension 2 branes

    SciTech Connect

    Kiley, Derrick

    2007-12-15

    It has recently been demonstrated that certain types of nontensional stress-energy can live on tensional codimension-2 branes, including gravitational shockwaves and small Schwarzschild black holes. In this paper we generalize the earlier Schwarzschild results, and construct the exact gravitational fields of small rotating black holes on a codimension-2 brane. We focus on the phenomenologically interesting case of a three-brane embedded in a spacetime with two compactified extra dimensions. For a nonzero tension on the brane, we verify that these solutions also show the ''lightning rod'' effect found in the Schwarzschild solutions, the net effect of which is to rescale the fundamental Planck mass. This allows for larger black hole parameters, such as the event horizon, angular momentum, and lifetime than would be naively expected for a tensionless brane. It is also found that a black hole with angular momentum pointing purely along the brane directions has a smaller horizon angular velocity than the corresponding tensionless case, while a hole with bulk components of angular momentum has a larger angular velocity.

  2. Gravity, black holes, and the universe

    SciTech Connect

    Nicolson, I.

    1981-01-01

    The book treats current understandings of the nature and properties of gravity, with particular emphasis on its role in the physics of black holes and the structure and evolution of the universe as a whole. The development of modern ideas on force, motion and gravity is traced from the systems of Aristotle and Ptolemy through the work of Copernicus, Galileo and Kepler to Newton's law of universal gravitation and Einstein's general theory of relativity. Particular attention is then given to the role of gravity in stellar motions and to the phenomena determined by the immense gravitational forces associated with bodies of such great density, including relativistic effects, tidal forces, space-time effects, event horizons, rotation, mass and electrical charge, the existence of naked singularities and white holes, and black-hole thermodynamics. The existence of actual black holes in the universe is considered, and various black-hole candidates in the Galaxy, quasars and galactic nuclei are indicated. The role of gravity in cosmology is then examined, with attention given to the implications of general relativity, the Hubble law, the age of the universe, the density of the universe and its eventual fate. Possible alternative to general relativity as a theory of gravitation are considered, including theories of variable gravitational constant, grand unified theories, and quantum gravity.

  3. Retrolensing by a charged black hole

    NASA Astrophysics Data System (ADS)

    Tsukamoto, Naoki; Gong, Yungui

    2017-03-01

    Compact objects with a light sphere such as black holes and wormholes can reflect light rays like a mirror. This gravitational lensing phenomenon is called retrolensing and it is an interesting tool to survey dark and compact objects with a light sphere near the solar system. In this paper, we calculate the deflection angle analytically in the strong deflection limit in the Reissner-Nordström spacetime without Taylor expanding it in the power of the electric charge. Using the obtained deflection angle in the strong deflection limit, we investigate the retrolensing light curves and the separation of double images by the light sphere of Reissner-Nordström black holes.

  4. Local Operators in the Eternal Black Hole.

    PubMed

    Papadodimas, Kyriakos; Raju, Suvrat

    2015-11-20

    In the AdS/CFT correspondence, states obtained by Hamiltonian evolution of the thermofield doubled state are also dual to an eternal black-hole geometry, which is glued to the boundary with a time shift generated by a large diffeomorphism. We describe gauge-invariant relational observables that probe the black hole interior in these states and constrain their properties using effective field theory. By adapting recent versions of the information paradox we show that these observables are necessarily described by state-dependent bulk-boundary maps, which we construct explicitly.

  5. Black holes in higher derivative gravity.

    PubMed

    Lü, H; Perkins, A; Pope, C N; Stelle, K S

    2015-05-01

    Extensions of Einstein gravity with higher-order derivative terms arise in string theory and other effective theories, as well as being of interest in their own right. In this Letter we study static black-hole solutions in the example of Einstein gravity with additional quadratic curvature terms. A Lichnerowicz-type theorem simplifies the analysis by establishing that they must have vanishing Ricci scalar curvature. By numerical methods we then demonstrate the existence of further black-hole solutions over and above the Schwarzschild solution. We discuss some of their thermodynamic properties, and show that they obey the first law of thermodynamics.

  6. Thermodynamical stability of the Bardeen black hole

    SciTech Connect

    Bretón, Nora; Perez Bergliaffa, Santiago E.

    2014-01-14

    We analyze the stability of the regular magnetic Bardeen black hole both thermodynamically and dynamically. For the thermodynamical analysis we consider a microcanonical ensemble and apply the turning point method. This method allows to decide a change in stability (or instability) of a system, requiring only the assumption of smoothness of the area functional. The dynamical stability is asserted using criteria based on the signs of the Lagrangian and its derivatives. It turns out from our analysis that the Bardeen black hole is both thermodynamically and dynamically stable.

  7. Binary Black Holes and Gravitational Waves

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2007-01-01

    The final merger of two black holes releases a tremendous amount of energy, more than the combined light from all the stars in the visible universe. This energy is emitted in the form of gravitational waves, and observing these sources with gravitational wave detectors such as LIGO and LISA requires that we know the pattern or fingerprint of the radiation emitted. Since black hole mergers take place in regions of extreme gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these wave patterns.

  8. Modelling Gravitational Radiation from Binary Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2006-01-01

    The final merger and coalescence of binary black holes is a key source of strong gravitational waves for the LISA mission. Observing these systems will allow us to probe the formation of cosmic structure to high redshifts and test general relativity directly in the strong-field, dynamical regime. Recently, major breakthroughs have been made in modeling black hole mergers using numerical relativity. This talk will survey these exciting developments, focusing on the gravitational waveforms and the recoil kicks produced from non-equal mass mergers.

  9. Black hole entropy without brick walls

    NASA Astrophysics Data System (ADS)

    Xiang, Li

    2002-07-01

    The properties of the thermal radiation are discussed by using the new equation of state density motivated by the generalized uncertainty relation in the quantum gravity. There is no burst at the last stage of the emission of a Schwarzschild black hole. When the new equation of state density is utilized to investigate the entropy of a scalar field outside the horizon of a static black hole, the divergence appearing in the brick wall model is removed, without any cutoff. The entropy proportional to the horizon area is derived from the contribution of the vicinity of the horizon.

  10. Normal Modes of Black Hole Accretion Disks

    SciTech Connect

    Ortega-Rodriguez, Manuel; Silbergleit, Alexander S.; Wagoner, Robert V.; /Stanford U., Phys. Dept. /KIPAC, Menlo Park

    2006-11-07

    This paper studies the hydrodynamical problem of normal modes of small adiabatic oscillations of relativistic barotropic thin accretion disks around black holes (and compact weakly magnetic neutron stars). Employing WKB techniques, we obtain the eigen frequencies and eigenfunctions of the modes for different values of the mass and angular momentum of the central black hole. We discuss the properties of the various types of modes and examine the role of viscosity, as it appears to render some of the modes unstable to rapid growth.

  11. Photon emission near extreme Kerr black holes

    NASA Astrophysics Data System (ADS)

    Porfyriadis, Achilleas P.; Shi, Yichen; Strominger, Andrew

    2017-03-01

    Ongoing astronomical efforts extract physical properties of black holes from electromagnetic emissions in their near-vicinity. This requires finding the null geodesics which extend from the near-horizon region out to a distant observatory. In general these are given by elliptic integrals which are often studied numerically. In this paper, for the interesting special case of extremally spinning Kerr black holes, we use an emergent near-horizon conformal symmetry to find near-superradiant geodesics analytically in terms of elementary functions.

  12. Self tuning scalar tensor black holes

    NASA Astrophysics Data System (ADS)

    Charmousis, Christos; Iosifidis, Damianos

    2015-04-01

    Studying a certain sub class of higher order Horndeski (scalar-tensor) theories we discuss a method discovered recently permitting analytic black hole solutions with a non trivial and regular scalar field. One of the solutions found has de Sitter asymptotics and self tunes the bulk cosmological constant. Using the aforementioned method we find and analyse new black hole solutions which can also have de Sitter asymptotics. By looking at small deviations of the integration constant responsible for self tuning we discuss the robustness of the self tuning mechanism. We find that neighboring solutions to the one previously found present also self tuning properties with unaltered effective cosmological constant.

  13. Entropy of 4D extremal black holes

    NASA Astrophysics Data System (ADS)

    Johnson, Clifford V.; Khuri, Ramzi R.; Myers, Robert C.

    1996-02-01

    We derive the Bekenstein-Hawking entropy formula for four-dimensional Reissner-Nordström extremal black holes in type II string theory. The derivation is performed in two separate (T-dual) weak coupling pictures. One uses a type IIB bound state problem of D5- and D1-branes, while the other uses a bound state problem of D0- and D4-branes with macroscopic fundamental type IIA strings. In both cases, the D-brane systems are also bound to a Kaluza-Klein monopole, which then yields the four-dimensional black hole at strong coupling.

  14. Winds of Change: How Black Holes May Shape Galaxies

    NASA Astrophysics Data System (ADS)

    2010-03-01

    New observations from NASA's Chandra X-ray Observatory provide evidence for powerful winds blowing away from the vicinity of a supermassive black hole in a nearby galaxy. This discovery indicates that "average" supermassive black holes may play an important role in the evolution of the galaxies in which they reside. For years, astronomers have known that a supermassive black hole grows in parallel with its host galaxy. And, it has long been suspected that material blown away from a black hole - as opposed to the fraction of material that falls into it -- alters the evolution of its host galaxy. A key question is whether such "black hole blowback" typically delivers enough power to have a significant impact. Powerful relativistic jets shot away from the biggest supermassive black holes in large, central galaxies in clusters like Perseus are seen to shape their host galaxies, but these are rare. What about less powerful, less focused galaxy-scale winds that should be much more common? "We're more interested here in seeing what an "average"-sized supermassive black hole can do to its galaxy, not the few, really big ones in the biggest galaxies," said Dan Evans of the Massachusetts Institute of Technology who presented these results at the High Energy Astrophysics Division of the American Astronomical Society meeting in Kona, Hawaii. Evans and his colleagues used Chandra for five days to observe NGC 1068, one of the nearest and brightest galaxies containing a rapidly growing supermassive black hole. This black hole is only about twice as massive as the one in the center of our Galaxy, which is considered to be a rather ordinary size. The X-ray images and spectra obtained using Chandra's High Energy Transmission Grating Spectrometer (HETGS) showed that a strong wind is being driven away from the center of NGC 1068 at a rate of about a million miles per hour. This wind is likely generated as surrounding gas is accelerated and heated as it swirls toward the black hole. A

  15. SETI among galaxies by virtue of black holes

    NASA Astrophysics Data System (ADS)

    Maccone, Claudio

    2012-09-01

    Black Hole radio bridge, having the distance of 2.5 million light years. The P2 Andromeda black hole is estimated to have a mass of about 40 million solar masses.The SgrA*-M32 (a dwarf elliptical galaxy satellite of Andromeda-M31) radio bridge, with a 2.65 million light year distance. The M32 black hole is estimated to have a mass of about 3 million solar masses.The SgrA*-M106 (also called NGC 4258, a spiral galaxy with anomalous arms) radio bridge, at about 24 million light years. The M106 black hole is estimated to have a mass of about 40 million solar masses.The SgrA*-Sombrero Galaxy (also called M104 or NGC 4594, an unbarred spiral galaxy) at a distance of 29.3 million light years. Its black hole is estimated to have a mass of 1 billion solar masses.The SgrA*-M87 radio bridge. M87 is the supergiant elliptical galaxy located at the center of the super-cluster of galaxies to which we belong, i.e. the Local Super Cluster, at the edge of which we are located. The distance between M87 and us is 53.5 million light years in the direction of the constellation of Virgo, which is why M87 and its surrounding clusters of galaxies are sometimes referred to as the Virgo Super Cluster. At the center of M87 is a supermassive black hole estimated to have a mass of 6.4 billion solar masses. M87 is also well known as “the jet galaxy” since a jet of energetic plasma originates at the core and extends out at least 5000 light-years.The conclusion that we draw from the mathematics describing these radio bridges across huge inter-galactic distances is surprising: they all perform better that the simple Sun-Alpha Cen A radio bridge, first studied in detail by this author in Ref. [1]. In other words, the powers necessary to keep the radio link between SgrA* and all of the above big black holes located in other nearby galaxies are smaller than the powers requested to keep the radio bridge between the Sun and Alpha Cen A. In other words still, despite inter-galactic distances are huge with

  16. Radion clouds around evaporating black holes

    SciTech Connect

    Morris, J. R.

    2009-08-15

    A Kaluza-Klein model, with a matter source associated with Hawking radiation from an evaporating black hole, is used to obtain a simple form for the radion effective potential. The environmental effect generally causes a matter-induced shift of the radion vacuum, resulting in the formation of a radion cloud around the hole. There is an albedo due to the radion cloud, with an energy-dependent reflection coefficient that depends upon the size of the extra dimensions and the temperature of the hole.

  17. STIS RECORDS A BLACK HOLE'S SIGNATURE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The colorful 'zigzag' on the right is not the work of a flamboyant artist, but the signature of a supermassive black hole in the center of galaxy M84, discovered by Hubble Space Telescope's Space Telescope Imaging Spectrograph (STIS). The image on the left, taken with Hubble's Wide Field Planetary and Camera 2 shows the core of the galaxy where the suspected black hole dwells. Astronomers mapped the motions of gas in the grip of the black hole's powerful gravitational pull by aligning the STIS's spectroscopic slit across the nucleus in a single exposure. The STIS data on the right shows the rotational motion of stars and gas along the slit. The change in wavelength records whether an object is moving toward or away from the observer. The larger the excursion from the centerline -- as seen as a green and yellow picture element (pixels) along the center strip, the greater the rotational velocity. If no black hole were present, the line would be nearly vertical across the scan. Instead, STIS's detector found the S-shape at the center of this scan, indicating a rapidly swirling disk of trapped material encircling the black hole. Along the S-shape from top to bottom, velocities skyrocket as seen in the rapid, dramatic swing to the left (blueshifted or approaching gas), then the region in the center simultaneously records the enormous speeds of the gas both approaching and receding for orbits in the immediate vicinity of the black hole, and then an equivalent swing from the right, back to the center line. STIS measures a velocity of 880,000 miles per hour (400 kilometers per second) within 26 light-years of the galaxy's center, where the black hole dwells. This motion allowed astronomers to calculate that the black hole contains at least 300 million solar masses. (Just as the mass of our Sun can be calculated from the orbital radii and speeds of the planets.) This observation demonstrates a direct connection between a supermassive black hole and activity (such as radio

  18. More Macrospicule Jets in On-Disk Coronal Holes

    NASA Technical Reports Server (NTRS)

    Adams, M. L.; Sterling, A. C.; Moore, R. L.

    2015-01-01

    We examine the magnetic structure and dynamics of multiple jets found in coronal holes close to or on disk center. All data are from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) of the Solar Dynamics Observatory (SDO). We report on observations of about ten jets in an equatorial coronal hole spanning 2011 February 27 and 28. We show the evolution of these jets in AIA 193 A, examine the magnetic field configuration and flux changes in the jet area, and discuss the probable trigger mechanism of these events. We reported on another jet in this same coronal hole on 2011 February 27, (is) approximately 13:04 UT (Adams et al 2014, ApJ, 783: 11). That jet is a previously-unrecognized variety of blowout jet, in which the base-edge bright point is a miniature filament-eruption flare arcade made by internal reconnection of the legs of the erupting field. In contrast, in the presently-accepted 'standard' picture for blowout jets, the base-edge bright point is made by interchange reconnection of initially-closed erupting jet-base field with ambient open field. This poster presents further evidence of the production of the base-edge bright point in blowout jets by internal reconnection. Our observations suggest that most of the bigger and brighter EUV jets in coronal holes are blowout jets of the new-found variety.

  19. Giant Black Hole Rips Apart Star

    NASA Astrophysics Data System (ADS)

    2004-02-01

    Thanks to two orbiting X-ray observatories, astronomers have the first strong evidence of a supermassive black hole ripping apart a star and consuming a portion of it. The event, captured by NASA's Chandra and ESA's XMM-Newton X-ray Observatories, had long been predicted by theory, but never confirmed. Astronomers believe a doomed star came too close to a giant black hole after being thrown off course by a close encounter with another star. As it neared the enormous gravity of the black hole, the star was stretched by tidal forces until it was torn apart. This discovery provides crucial information about how these black holes grow and affect surrounding stars and gas. "Stars can survive being stretched a small amount, as they are in binary star systems, but this star was stretched beyond its breaking point," said Stefanie Komossa of the Max Planck Institute for Extraterrestrial Physics (MPE) in Germany, leader of the international team of researchers. "This unlucky star just wandered into the wrong neighborhood." While other observations have hinted stars are destroyed by black holes (events known as "stellar tidal disruptions"), these new results are the first strong evidence. Evidence already exists for supermassive black holes in many galaxies, but looking for tidal disruptions represents a completely independent way to search for black holes. Observations like these are urgently needed to determine how quickly black holes can grow by swallowing neighboring stars. Animation of Star Ripped Apart by Giant Black Hole Star Ripped Apart by Giant Black Hole Observations with Chandra and XMM-Newton, combined with earlier images from the German Roentgen satellite, detected a powerful X-ray outburst from the center of the galaxy RX J1242-11. This outburst, one of the most extreme ever detected in a galaxy, was caused by gas from the destroyed star that was heated to millions of degrees Celsius before being swallowed by the black hole. The energy liberated in the process

  20. Thermodynamic phase transition in the rainbow Schwarzschild black hole

    SciTech Connect

    Gim, Yongwan; Kim, Wontae E-mail: wtkim@sogang.ac.kr

    2014-10-01

    We study the thermodynamic phase transition in the rainbow Schwarzschild black hole where the metric depends on the energy of the test particle. Identifying the black hole temperature with the energy from the modified dispersion relation, we obtain the modified entropy and thermodynamic energy along with the modified local temperature in the cavity to provide well defined black hole states. It is found that apart from the conventional critical temperature related to Hawking-Page phase transition there appears an additional critical temperature which is of relevance to the existence of a locally stable tiny black hole; however, the off-shell free energy tells us that this black hole should eventually tunnel into the stable large black hole. Finally, we discuss the reason why the temperature near the horizon is finite in the rainbow black hole by employing the running gravitational coupling constant, whereas it is divergent near the horizon in the ordinary Schwarzschild black hole.

  1. Deflection Angle and R-Charged Black Holes

    NASA Astrophysics Data System (ADS)

    Saadat, Hassan

    2013-10-01

    In this paper we consider R-charged black holes with three electrical charges and study deflection angle. We confirmed result of previous study that the black hole charges increased the deflection angle.

  2. Thermodynamical Stability of a New Regular Black Hole

    NASA Astrophysics Data System (ADS)

    Saadat, Hassan

    2013-09-01

    In this paper we consider a new regular black hole and calculate thermodynamical variables such as entropy, specific heat and free energy. Then we study thermodynamical stability of this black hole by using the specific heat in constant volume.

  3. Swift Probes Exotic Object: 'Kicked' Black Hole or Mega Star?

    NASA Video Gallery

    Zoom into Markarian 177 and SDSS1133 and see how they compare with a simulated galaxy collision. When the central black holes in these galaxies combine, a "kick" launches the merged black hole on a...

  4. Dance of Two Monster Black Holes

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-03-01

    This past December, researchers all over the world watched an outburst from the enormous black hole in OJ 287 an outburst that had been predicted years ago using the general theory of relativity.Outbursts from Black-Hole OrbitsOJ 287 is one of the largest supermassive black holes known, weighing in at 18 billion solar masses. Located about 3.5 billion light-years away, this monster quasar is bright enough that it was first observed as early as the 1890s. What makes OJ 287 especially interesting, however, is that its light curve exhibits prominent outbursts roughly every 12 years.Diagram illustrating the orbit of the secondary black hole (shown in blue) in OJ 287 from 2000 to 2023. We see outbursts (the yellow bubbles) every time the secondary black hole crosses the accretion disk (shown in red, ina side view) surrounding the primary (the black circle). [Valtonen et al. 2016]What causes the outbursts? Astronomers think that there is a second supermassive black hole, ~100 times smaller, inspiraling as it orbits the central monster and set to merge within the next 10,000 years. In this model, the primary black hole of OJ 287 is surrounded by a hot accretion disk. As the secondary black hole orbits the primary, it regularly punches through this accretion disk, heating the material and causing the release of expanding bubbles of hot gas pulled from the disk. This gas then radiates thermally, causing the outbursts we see.Attempts to model this scenario using Newtonian orbits all fail; the timing of the secondary black holes crossings through the accretion disk (as measured by when we see the outbursts) can only be explained by a model incorporating general-relativistic effects on the orbit. Careful observations and precise timing of these outbursts therefore provide an excellent test of general relativity.Watching a Predicted CrossingThe model of OJ 287 predicted another disk crossing in December 2015, so professional and amateur astronomers around the world readied more

  5. Semiclassical S-matrix for black holes

    DOE PAGES

    Bezrukov, Fedor; Levkov, Dmitry; Sibiryakov, Sergey

    2015-12-01

    In this study, we propose a semiclassical method to calculate S-matrix elements for two-stage gravitational transitions involving matter collapse into a black hole and evaporation of the latter. The method consistently incorporates back-reaction of the collapsing and emitted quanta on the metric. We illustrate the method in several toy models describing spherical self-gravitating shells in asymptotically flat and AdS space-times. We find that electrically neutral shells reflect via the above collapse-evaporation process with probability exp(–B), where B is the Bekenstein-Hawking entropy of the intermediate black hole. This is consistent with interpretation of exp(B) as the number of black hole states.more » The same expression for the probability is obtained in the case of charged shells if one takes into account instability of the Cauchy horizon of the intermediate Reissner-Nordström black hole. As a result, our semiclassical method opens a new systematic approach to the gravitational S-matrix in the non-perturbative regime.« less

  6. Semiclassical S-matrix for black holes

    SciTech Connect

    Bezrukov, Fedor; Levkov, Dmitry; Sibiryakov, Sergey

    2015-12-01

    In this study, we propose a semiclassical method to calculate S-matrix elements for two-stage gravitational transitions involving matter collapse into a black hole and evaporation of the latter. The method consistently incorporates back-reaction of the collapsing and emitted quanta on the metric. We illustrate the method in several toy models describing spherical self-gravitating shells in asymptotically flat and AdS space-times. We find that electrically neutral shells reflect via the above collapse-evaporation process with probability exp(–B), where B is the Bekenstein-Hawking entropy of the intermediate black hole. This is consistent with interpretation of exp(B) as the number of black hole states. The same expression for the probability is obtained in the case of charged shells if one takes into account instability of the Cauchy horizon of the intermediate Reissner-Nordström black hole. As a result, our semiclassical method opens a new systematic approach to the gravitational S-matrix in the non-perturbative regime.

  7. Black Holes and the Large Hadron Collider

    ERIC Educational Resources Information Center

    Roy, Arunava

    2011-01-01

    The European Center for Nuclear Research or CERN's Large Hadron Collider (LHC) has caught our attention partly due to the film "Angels and Demons." In the movie, an antimatter bomb attack on the Vatican is foiled by the protagonist. Perhaps just as controversial is the formation of mini black holes (BHs). Recently, the American Physical Society…

  8. Nonthermal nature of incipient extremal black holes

    NASA Astrophysics Data System (ADS)

    Liberati, Stefano; Rothman, Tony; Sonego, Sebastiano

    2000-07-01

    We examine particle production from spherical bodies collapsing into extremal Reissner-Nordström black holes. Kruskal coordinates become ill defined in the extremal case, but we are able to find a simple generalization of them that is good in this limit. The extension allows us to calculate the late-time world line of the center of the collapsing star, thus establishing a correspondence with a uniformly accelerated mirror in Minkowski spacetime. The spectrum of created particles associated with such uniform acceleration is nonthermal, indicating that a temperature is not defined. Moreover, the spectrum contains a constant that depends on the history of the collapsing object. At first sight this points to a violation of the no-hair theorems; however, the expectation value of the stress-energy-momentum tensor is zero and its variance vanishes as a power law at late times. Hence, both the no-hair theorems and the cosmic censorship conjecture are preserved. The power-law decay of the variance is in distinction to the exponential falloff of a nonextremal black hole. Therefore, although the vanishing of the stress tensor's expectation value is consistent with a thermal state at zero temperature, the incipient black hole does not behave as a thermal object at any time and cannot be regarded as the thermodynamic limit of a nonextremal black hole, regardless of the fact that the final product of collapse is quiescent.

  9. Supermassive Black Hole Binaries: The Search Continues

    NASA Astrophysics Data System (ADS)

    Bogdanović, Tamara

    Gravitationally bound supermassive black hole binaries (SBHBs) are thought to be a natural product of galactic mergers and growth of the large scale structure in the universe. They however remain observationally elusive, thus raising a question about characteristic observational signatures associated with these systems. In this conference proceeding I discuss current theoretical understanding and latest advances and prospects in observational searches for SBHBs.

  10. Constraints for transonic black hole accretion

    NASA Technical Reports Server (NTRS)

    Abramowicz, Marek A.; Kato, Shoji

    1989-01-01

    Regularity conditions and global topological constraints leave some forbidden regions in the parameter space of the transonic isothermal, rotating matter onto black holes. Unstable flows occupy regions touching the boundaries of the forbidden regions. The astrophysical consequences of these results are discussed.

  11. AN ANOMALOUS QUIESCENT STELLAR MASS BLACK HOLE

    SciTech Connect

    Reynolds, Mark T.; Miller, Jon M.

    2011-06-10

    We present the results of a 40 ks Chandra observation of the quiescent stellar mass black hole GS 1354-64. A total of 266 net counts are detected at the position of this system. The resulting spectrum is found to be consistent with the spectra of previously observed quiescent black holes, i.e., a power law with a photon index of {Gamma} {approx} 2. The inferred luminosity in the 0.5-10 keV band is found to lie in the range 0.5-6.5 x 10{sup 34} erg s{sup -1}, where the uncertainty in the distance is the dominant source of this large luminosity range. Nonetheless, this luminosity is over an order of magnitude greater than that expected from the known distribution of quiescent stellar mass black hole luminosities and makes GS 1354-64 the only known stellar mass black hole to disagree with this relation. This observation suggests the possibility of significant accretion persisting in the quiescent state.

  12. ULXs: Neutron stars versus black holes

    NASA Astrophysics Data System (ADS)

    King, Andrew; Lasota, Jean-Pierre

    2016-05-01

    We consider ultraluminous X-ray systems (ULXs) where the accretor is a neutron star rather than a black hole. We show that the recently discovered example (M82 X-2) fits naturally into the simple picture of ULXs as beamed X-ray sources fed at super-Eddington rates, provided that its magnetic field is weaker (≃1011G) than a new-born X-ray pulsar, as expected if there has been mass gain. Continuing accretion is likely to weaken the field to the point that pulsing stops, and make the system indistinguishable from a ULX containing a black hole. Accordingly we suggest that a significant fraction of all ULXs may actually contain neutron star accretors rather than black holes, reflecting the neutron-star fraction among their X-ray binary progenitors. We emphasize that neutron-star ULXs are likely to have higher apparent luminosities than black hole ULXs for a given mass transfer rate, as their tighter beaming outweighs their lower Eddington luminosities. This further increases the likely proportion of neutron-star accretors among all ULXs. Cygnus X-2 is probably a typical descendant of neutron-star ULXs, which may therefore ultimately end as millisecond pulsar binaries with massive white dwarf companions.

  13. Hawking Temperature of Acoustic Black Hole

    NASA Astrophysics Data System (ADS)

    Xie, Zhi Kun

    2014-09-01

    Using a new tortoise coordinate transformation, the Hawking radiation of the acoustic black hole was discussed by studying the Klein-Gordon equation of scalar particles in the curve space-time. It was found that the Hawking temperature is connected with time and position on the event horizon.

  14. Black Holes and the Centers of Galaxies

    NASA Astrophysics Data System (ADS)

    Richstone, Douglas

    1997-07-01

    We propose to continue our survey of centers of nearby galaxies. The major goal for Cycle 7 is to survey an unbiased set of galaxies with a potentially wide range of black hole masses. The results will constrain the prevalence and formation of massive black holes and their relationship to AGN's. Over the last several years, we have used HST to characterize the scaling laws for galaxy centers, to identify an apparent dichotomy in galaxy types based on their central light profiles, and to identify new black hole candidates and confirm ground-based results on known candidates. In the STIS epoch, we wish to capitalize on the presence of a genuine slit spectrograph to study the central stellar dynamics of a large set of systematically selected elliptical and S0 galaxies. The sample for this cycle has been carefully chosen to optimize our leverage on the character of a proposed correlation of black hole mass with galaxy mass. In addition, high-S/N observations of line profiles should permit us to distinguish between BHs and anisotropic stellar orbits, a critical degeneracy that has long plagued this subject.

  15. Binary Black Holes: Mergers, Dynamics, and Waveforms

    NASA Astrophysics Data System (ADS)

    Centrella, Joan

    2007-04-01

    The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based interferometer LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, data analysis, and astrophysics.

  16. Tachyon condensation and black hole entropy.

    PubMed

    Dabholkar, Atish

    2002-03-04

    String propagation on a cone with deficit angle 2pi(1-1 / N) is considered for the purpose of computing the entropy of a large mass black hole. The entropy computed using the recent results on condensation of twisted-sector tachyons in this theory is found to be in precise agreement with the Bekenstein-Hawking entropy.

  17. Entropy and temperatures of Nariai black hole

    NASA Astrophysics Data System (ADS)

    Eune, Myungseok; Kim, Wontae

    2013-06-01

    The statistical entropy of the Nariai black hole in a thermal equilibrium is calculated by using the brick-wall method. Even if the temperature depends on the choice of the timelike Killing vector, the entropy can be written by the ordinary area law which agrees with the Wald entropy. We discuss some physical consequences of this result and the properties of the temperatures.

  18. Initial Data for Black Hole Collisions

    NASA Astrophysics Data System (ADS)

    Rauber, Joel David

    A problem of considerable interest in relativistic astrophysics is to determine the gravitational radiation produced by collisions of compact objects, such as black holes. Such collisions may occur, for example, in the nuclei of galaxies. This problem requires that one solve the Einstein equation without limiting approximations, for example, as a Cauchy problem. Therefore, one must first construct the initial data. The extrinsic curvature on an initial spacelike hypersurface of two black holes with axisymmetric parallel spins is derived in terms of an analytic infinite series. Other two body configurations are also considered. The extrinsic curvature is constructed so that the resulting spacetime will have the topology of two Einstein-Rosen bridges; a physical equivalence of the top and bottom sheets of the initial hypersurface is also built in. It is shown that one may a priori specify the spins of the two black holes. The extrinsic curvature, so constructed, is not derivable from a potential. An appropriate numerical problem for the conformal factor is posed and examined in the above configurations. Efforts at using multi-grid differencing schemes for solving the differential equations are discussed. In order to time evolve a black hole interaction or collision, the extrinsic curvature and conformal factor must be completely specified on an initial slice of spacetime.

  19. Astronomical tests for quantum black hole structure

    NASA Astrophysics Data System (ADS)

    Giddings, Steven B.

    2017-03-01

    Black holes present a profound challenge to our current foundations of physics, and an exciting era of astronomy is just opening in which gravitational-wave observation and very-long-baseline interferometry may provide important hints about the new principles of physics needed.

  20. Static black hole uniqueness and Penrose inequality

    SciTech Connect

    Mizuno, Ryosuke; Shiromizu, Tetsuya; Ohashi, Seiju

    2010-02-15

    Under certain conditions, we offer a new way to prove the uniqueness of the static black hole in higher dimensional asymptotically flat spacetimes. In the proof, the Penrose inequality plays a key role in higher dimensions as well as four dimensions.

  1. Black Holes Masses in Seyfert Galaxies

    NASA Technical Reports Server (NTRS)

    Macchetto, F. D.

    2004-01-01

    There is increasing evidence for the existence of supermassive black holes at the centers of all galaxies, and much work is being devoted to understand the process that lead to their formation, the duty cycle for the active phase of these black holes and the relevant fueling mechanisms. Seyfert galaxies determined by HST high spatial resolution observations of the kinematics of the central regions. The study of the gas kinematics provides a unique tool to probe the gravitational potential of the nuclear regions of Seyfert galaxies down to a limit radius of a few parsecs. This is particularly important to detect and measure the mass associated with any central massive black hole. We have obtained high spatial resolution spectra of a number of Seyfert galaxies, with the STIS G430M and G750M gratings, and we have been able to separate the emission line components associated with different velocity systems. We have derived two-dimensional velocity fields and determined the mass of the central black hole with good precision for each of the galaxies.

  2. Black holes and high energy physics

    NASA Astrophysics Data System (ADS)

    Grib, A. A.; Pavlov, Yu. V.

    2016-01-01

    Three mechanisms of getting high energies in particle collisions in the ergosphere of the rotating black holes are considered. The consequences of these mechanisms for observation of ultra high energy cosmic rays particles on the Earth as result of conversion of superheavy dark matter particles into ordinary particles are discussed.

  3. Precocious Supermassive Black Holes Challenge Theories

    NASA Astrophysics Data System (ADS)

    2004-11-01

    NASA's Chandra X-ray Observatory has obtained definitive evidence that a distant quasar formed less than a billion years after the Big Bang contains a fully-grown supermassive black hole generating energy at the rate of twenty trillion Suns. The existence of such massive black holes at this early epoch of the Universe challenges theories of the formation of galaxies and supermassive black holes. Astronomers Daniel Schwartz and Shanil Virani of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA observed the quasar, known as SDSSp J1306, which is 12.7 billion light years away. Since the Universe is estimated to be 13.7 billion years old, we see the quasar as it was a billion years after the Big Bang. They found that the distribution of X-rays with energy, or X-ray spectrum, is indistinguishable from that of nearby, older quasars. Likewise, the relative brightness at optical and X-ray wavelengths of SDSSp J1306 was similar to that of the nearby group of quasars. Optical observations suggest that the mass of the black hole is about a billion solar masses. Illustration of Quasar SDSSp J1306 Illustration of Quasar SDSSp J1306 Evidence of another early-epoch supermassive black hole was published previously by a team of scientists from the California Institute of Technology and the United Kingdom using the XMM-Newton X-ray satellite. They observed the quasar SDSSp J1030 at a distance of 12.8 billion light years and found essentially the same result for the X-ray spectrum as the Smithsonian scientists found for SDSSp J1306. Chandra's precise location and spectrum for SDSSp J1306 with nearly the same properties eliminate any lingering uncertainty that precocious supermassive black holes exist. "These two results seem to indicate that the way supermassive black holes produce X-rays has remained essentially the same from a very early date in the Universe," said Schwartz. "This implies that the central black hole engine in a massive galaxy was formed very soon

  4. SLIM DISKS AROUND KERR BLACK HOLES REVISITED

    SciTech Connect

    Sadowski, Aleksander

    2009-08-01

    We investigate stationary slim accretion disks around Kerr black holes. We construct a new numerical method based on the relaxation technique. We systematically cover the whole parameter space relevant to stellar mass X-ray binaries. We also notice some non-monotonic features in the disk structure, overlooked in previous studies.

  5. Warped AdS3 black holes

    NASA Astrophysics Data System (ADS)

    Anninos, Dionysios; Li, Wei; Padi, Megha; Song, Wei; Strominger, Andrew

    2009-03-01

    Three dimensional topologically massive gravity (TMG) with a negative cosmological constant -l-2 and positive Newton constant G admits an AdS3 vacuum solution for any value of the graviton mass μ. These are all known to be perturbatively unstable except at the recently explored chiral point μl = 1. However we show herein that for every value of μl ≠ 3 there are two other (potentially stable) vacuum solutions given by SL(2,Bbb R) × U(1)-invariant warped AdS3 geometries, with a timelike or spacelike U(1) isometry. Critical behavior occurs at μl = 3, where the warping transitions from a stretching to a squashing, and there are a pair of warped solutions with a null U(1) isometry. For μl > 3, there are known warped black hole solutions which are asymptotic to warped AdS3. We show that these black holes are discrete quotients of warped AdS3 just as BTZ black holes are discrete quotients of ordinary AdS3. Moreover new solutions of this type, relevant to any theory with warped AdS3 solutions, are exhibited. Finally we note that the black hole thermodynamics is consistent with the hypothesis that, for μl > 3, the warped AdS3 ground state of TMG is holographically dual to a 2D boundary CFT with central charges c_R-formula and c_L-formula.

  6. Warped AdS3 black holes

    NASA Astrophysics Data System (ADS)

    Song, Wei; Anninos, Dionysios; Li, Wei; Padi, Megha; Strominger, Andrew

    2009-03-01

    Three dimensional topologically massive gravity (TMG) with a negative cosmological constant -ell-2 and positive Newton constant G admits an AdS3 vacuum solution for any value of the graviton mass μ. These are all known to be perturbatively unstable except at the recently explored chiral point μell = 1. However we show herein that for every value of μell ≠ 3 there are two other (potentially stable) vacuum solutions given by SL(2,Bbb R) × U(1)-invariant warped AdS3 geometries, with a timelike or spacelike U(1) isometry. Critical behavior occurs at μell = 3, where the warping transitions from a stretching to a squashing, and there are a pair of warped solutions with a null U(1) isometry. For μell > 3, there are known warped black hole solutions which are asymptotic to warped AdS3. We show that these black holes are discrete quotients of warped AdS3 just as BTZ black holes are discrete quotients of ordinary AdS3. Moreover new solutions of this type, relevant to any theory with warped AdS3 solutions, are exhibited. Finally we note that the black hole thermodynamics is consistent with the hypothesis that, for μell > 3, the warped AdS3 ground state of TMG is holographically dual to a 2D boundary CFT with central charges c_R-formula and c_L-formula.

  7. Discriminating Supersymmetry and Black Holes at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Roy, Arunava; Cavaglia, Marco

    2008-04-01

    We assess the distinguishability between supersymmetry and black hole events at the Large Hadron Collider. Black hole events are simulated with the CATFISH black hole generator. Supersymmetry simulations use a combination of PYTHIA and ISAJET. Our study, based on event shape variables, visible and missing momenta, and analysis of dilepton events, shows that supersymmetry and black hole events at the LHC can be easily discriminated.

  8. Phantom black holes and critical phenomena

    SciTech Connect

    Azreg-Aïnou, Mustapha; Marques, Glauber T.

    2014-07-01

    We consider the two classes cosh and sinh of normal and phantom black holes of Einstein-Maxwell-dilaton theory. The thermodynamics of these holes is characterized by heat capacities that may have both signs depending on the parameters of the theory. Leaving aside the normal Reissner-Nordström black hole, it is shown that only some phantom black holes of both classes exhibit critical phenomena. The two classes share a nonextremality, but special, critical point where the transition is continuous and the heat capacity, at constant charge, changes sign with an infinite discontinuity. This point yields a classification scheme for critical points. It is concluded that the two unstable and stable phases coexist on one side of the criticality state and disappear on the other side, that is, there is no configuration where only one phase exists. The sinh class has an extremality critical point where the entropy diverges. The transition from extremality to nonextremality with the charge held constant is accompanied by a loss of mass and an increase in the temperature. A special case of this transition is when the hole is isolated (microcanonical ensemble), it will evolve by emission of energy, which results in a decrease of its mass, to the final state of minimum mass and vanishing heat capacity. The Ehrenfest scheme of classification is inaccurate in this case but the generalized one due to Hilfer leads to conclude that the transition is of order less than unity. Fluctuations near criticality are also investigated.

  9. Inclination Angles of Black Hole X-Ray Binaries Manifest Strong Gravity around Black Holes

    NASA Technical Reports Server (NTRS)

    Zhang, S. N.; Zhang, Xiao-Ling; Yao, Yangsen

    2002-01-01

    System inclination angles have been determined for about 15 X-ray binaries, in which stellar mass black holes are considered to exist. These inclination angles range between 25 degrees and 80 degrees, but peaked between 60-70 degrees. This peak is not explained in the frame work of Newtonian gravity. However, this peak is reproduced naturally if we model the observed X-ray radiations as being produced in the accretion disks very close to the black hole horizons, where the extremely strong general and special relativistic effects, caused by the extremely strong gravity near the black hole horizons, modify the local radiation significantly as the X-rays propagate to the remote observer. Therefore the peak of the inclination angle distribution provides evidence or strong gravity around stellar mass black holes.

  10. Black Hole production in cosmic ray showers

    NASA Astrophysics Data System (ADS)

    Roy, Arunava; Cavaglia, Marco

    2007-04-01

    One way around the hierarchy problem of particle physics is to introduce large extra dimensions (LED). This suggests that gravity may become strong at the TeV and so production of scale black holes (BH's) would be possible by particle colliders and UHECR's. The interesting question is, what would be the BH signatures and whether we would detect them at the LHC or at the Auger Observatory. We also deal with the case of rotating BH's and how they may decay. Page [1976] showed that the power emitted from rotating four-dimensional BH's increases with angular momentum and so it is worth considering if this picture changes in higher dimensions. Also discussed is the case of excited string excitations from the decay of strings produced by neutrino-quark interactions. Ref: Page, D.N. (1976), Particle emission rates from a black hole. II. Massless particles from a rotating hole, Phys. Rev. D 14, 3260 - 3273

  11. Thermodynamics and luminosities of rainbow black holes

    SciTech Connect

    Mu, Benrong; Wang, Peng; Yang, Haitang E-mail: pengw@scu.edu.cn

    2015-11-01

    Doubly special relativity (DSR) is an effective model for encoding quantum gravity in flat spacetime. As result of the nonlinearity of the Lorentz transformation, the energy-momentum dispersion relation is modified. One simple way to import DSR to curved spacetime is ''Gravity's rainbow'', where the spacetime background felt by a test particle would depend on its energy. Focusing on the ''Amelino-Camelia dispersion relation'' which is E{sup 2} = m{sup 2}+p{sup 2}[1−η(E/m{sub p}){sup n}] with n > 0, we investigate the thermodynamical properties of a Schwarzschild black hole and a static uncharged black string for all possible values of η and n in the framework of rainbow gravity. It shows that there are non-vanishing minimum masses for these two black holes in the cases with η < 0 and n ≥ 2. Considering effects of rainbow gravity on both the Hawking temperature and radius of the event horizon, we use the geometric optics approximation to compute luminosities of a 2D black hole, a Schwarzschild one and a static uncharged black string. It is found that the luminosities can be significantly suppressed or boosted depending on the values of η and n.

  12. Thermodynamics and luminosities of rainbow black holes

    NASA Astrophysics Data System (ADS)

    Mu, Benrong; Wang, Peng; Yang, Haitang

    2015-11-01

    Doubly special relativity (DSR) is an effective model for encoding quantum gravity in flat spacetime. As result of the nonlinearity of the Lorentz transformation, the energy-momentum dispersion relation is modified. One simple way to import DSR to curved spacetime is ``Gravity's rainbow'', where the spacetime background felt by a test particle would depend on its energy. Focusing on the ``Amelino-Camelia dispersion relation'' which is E2 = m2+p2[1-η(E/mp)n] with n > 0, we investigate the thermodynamical properties of a Schwarzschild black hole and a static uncharged black string for all possible values of η and n in the framework of rainbow gravity. It shows that there are non-vanishing minimum masses for these two black holes in the cases with η < 0 and n >= 2. Considering effects of rainbow gravity on both the Hawking temperature and radius of the event horizon, we use the geometric optics approximation to compute luminosities of a 2D black hole, a Schwarzschild one and a static uncharged black string. It is found that the luminosities can be significantly suppressed or boosted depending on the values of η and n.

  13. Are black holes with hair a normal state of matter?

    SciTech Connect

    Nieuwenhuizen, Th. M.

    2011-03-28

    Recent observations put forward that quasars are black holes with a magnetic dipole moment and no event horizon. To model hairy black holes a quantum field for hydrogen is considered in curved space, coupled to the scalar curvature. An exact, regular solution for the interior metric occurs for supermassive black holes. The equation of state is p = -{rho}c{sup 2}/3.

  14. Charged fermions tunneling from accelerating and rotating black holes

    SciTech Connect

    Rehman, Mudassar; Saifullah, K. E-mail: saifullah@qau.edu.pk

    2011-03-01

    We study Hawking radiation of charged fermions from accelerating and rotating black holes with electric and magnetic charges. We calculate the tunneling probabilities of incoming and outgoing fermionic particles and find the Hawking temperature of these black holes. We also provide an explicit expression of the classical action for the massive and massless particles in the background of these black holes.

  15. Black holes with surrounding matter in scalar-tensor theories.

    PubMed

    Cardoso, Vitor; Carucci, Isabella P; Pani, Paolo; Sotiriou, Thomas P

    2013-09-13

    We uncover two mechanisms that can render Kerr black holes unstable in scalar-tensor gravity, both associated with the presence of matter in the vicinity of the black hole and the fact that this introduces an effective mass for the scalar. Our results highlight the importance of understanding the structure of spacetime in realistic, astrophysical black holes in scalar-tensor theories.

  16. R-Charged Black Hole and Holographic Superfluid

    NASA Astrophysics Data System (ADS)

    Saadat, Hassan

    2012-11-01

    In this paper we consider an interesting model of superfluid and use AdS/CFT correspondence to extract sound modes. We assume that dual picture of superfluid is the R-charged black hole with two equal charges. By using hydrodynamic variables of such a black hole we obtain first, second and fourth sound modes as a function of black hole charge.

  17. Formation of black hole and emission of gravitational waves.

    PubMed

    Nakamura, Takashi

    2006-12-01

    Numerical simulations were performed for the formation process of rotating black holes. It is suggested that Kerr black holes are formed for wide ranges of initial parameters. The nature of gravitational waves from a test particle falling into a Kerr black hole as well as the development of 3D numerical relativity for the coalescing binary neutron stars are discussed.

  18. Formation of black hole and emission of gravitational waves

    PubMed Central

    Nakamura, Takashi

    2006-01-01

    Numerical simulations were performed for the formation process of rotating black holes. It is suggested that Kerr black holes are formed for wide ranges of initial parameters. The nature of gravitational waves from a test particle falling into a Kerr black hole as well as the development of 3D numerical relativity for the coalescing binary neutron stars are discussed. PMID:25792793

  19. Physical properties of a soliton black hole at finite temperature

    NASA Astrophysics Data System (ADS)

    Pan, Rong-Shi; Su, Ru-Keng

    1992-03-01

    It is shown that the nontopological scalar black hole suggested by Friedberg, Lee, and Pang is dynamically stable at finite temperature. The heat capacity of a scalar soliton black hole is positive. The physical properties of a scalar black hole at finite temperature are discussed.

  20. Dynamical structure of magnetized dissipative accretion flow around black holes

    NASA Astrophysics Data System (ADS)

    Sarkar, Biplob; Das, Santabrata

    2016-09-01

    We study the global structure of optically thin, advection dominated, magnetized accretion flow around black holes. We consider the magnetic field to be turbulent in nature and dominated by the toroidal component. With this, we obtain the complete set of accretion solutions for dissipative flows where bremsstrahlung process is regarded as the dominant cooling mechanism. We show that rotating magnetized accretion flow experiences virtual barrier around black hole due to centrifugal repulsion that can trigger the discontinuous transition of the flow variables in the form of shock waves. We examine the properties of the shock waves and find that the dynamics of the post-shock corona (PSC) is controlled by the flow parameters, namely viscosity, cooling rate and strength of the magnetic field, respectively. We separate the effective region of the parameter space for standing shock and observe that shock can form for wide range of flow parameters. We obtain the critical viscosity parameter that allows global accretion solutions including shocks. We estimate the energy dissipation at the PSC from where a part of the accreting matter can deflect as outflows and jets. We compare the maximum energy that could be extracted from the PSC and the observed radio luminosity values for several supermassive black hole sources and the observational implications of our present analysis are discussed.