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Sample records for supermassive black-hole growth

  1. Growth of Supermassive Black Holes, Galaxy Mergers, and Binary SMBHs

    NASA Astrophysics Data System (ADS)

    Komossa, Stefanie

    2015-08-01

    Galaxy mergers are the sites of major black hole growth. They power luminous quasars, and form supermassive binary black holes (SMBBHs) at their centers. Coalescing binaries are among the strongest sources of gravitational waves (GWs) in the universe. Studying the early and advanced stages galaxy merging, and the onset of accretion onto one or both BHs, informs us about feedback processes, and the origin of the scaling relations between SMBHs and their host galaxies. During gas-rich and gas-poor mergers, the initial conditions are set which later determine the amplitude of GW recoil. Identification of the compact SMBBHs, at parsec and sub-parsec scales, provides us with important constraints on the interaction processes that govern the shrinkage of the binary beyond "the final parsec". Here, I give an overview of the status of observations, important open questions, and future surveys, with an emphasis on SMBBHs.

  2. Overlapping inflow events as catalysts for supermassive black hole growth

    NASA Astrophysics Data System (ADS)

    Carmona-Loaiza, Juan M.; Colpi, Monica; Dotti, Massimo; Valdarnini, Riccardo

    2014-02-01

    One of the greatest issues in modelling black hole fuelling is our lack of understanding of the processes by which gas loses angular momentum and falls from galactic scales down to the nuclear region where an accretion disc forms, subsequently guiding the inflow of gas down to the black hole horizon. It is feared that gas at larger scales might still retain enough angular momentum and settle into a larger scale disc with very low or no inflow to form or replenish the inner accretion disc (on ˜0.01 pc scales). In this paper we report on hydrodynamical simulations of rotating infalling gas shells impacting at different angles on to a pre-existing, primitive large-scale (˜10 pc) disc around a supermassive black hole. The aim is to explore how the interaction between the shell and the disc redistributes the angular momentum on scales close to the black hole's sphere of influence. Angular momentum redistribution via hydrodynamical shocks leads to inflows of gas across the inner boundary, enhancing the inflow rate by more than 2-3 orders of magnitude. In all cases, the gas inflow rate across the inner parsec is higher than in the absence of the interaction, and the orientation of the angular momentum of the flow in the region changes with time due to gas mixing. Warped discs or nested misaligned rings form depending on the angular momentum content of the infalling shell relative to the disc. In the cases in which the shell falls in near counter-rotation, part of the resulting flows settle into an inner dense disc which becomes more susceptible to mass transfer.

  3. New observational constraints on the growth of the first supermassive black holes

    SciTech Connect

    Treister, E.; Schawinski, K.; Volonteri, M.; Natarajan, P.

    2013-12-01

    We constrain the total accreted mass density in supermassive black holes at z > 6, inferred via the upper limit derived from the integrated X-ray emission from a sample of photometrically selected galaxy candidates. Studying galaxies obtained from the deepest Hubble Space Telescope images combined with the Chandra 4 Ms observations of the Chandra Deep Field-South, we achieve the most restrictive constraints on total black hole growth in the early universe. We estimate an accreted mass density <1000 M {sub ☉} Mpc{sup –3} at z ∼ 6, significantly lower than the previous predictions from some existing models of early black hole growth and earlier prior observations. These results place interesting constraints on early black hole growth and mass assembly by accretion and imply one or more of the following: (1) only a fraction of the luminous galaxies at this epoch contain active black holes; (2) most black hole growth at early epochs happens in dusty and/or less massive—as yet undetected—host galaxies; (3) there is a significant fraction of low-z interlopers in the galaxy sample; (4) early black hole growth is radiatively inefficient, heavily obscured, and/or due to black hole mergers as opposed to accretion; or (5) the bulk of the black hole growth occurs at late times. All of these possibilities have important implications for our understanding of high-redshift seed formation models.

  4. Weighing supermassive black holes

    NASA Astrophysics Data System (ADS)

    Rafiee, Alireza

    We calculate the black hole masses for a sample of 27728 quasars selected from the Sloan Digital Sky Survey (SDSS) Data Release 3 (DR3). To ensure a high signal-to-noise ratio, we reconstruct quasar spectra for this large sample of quasars using the eigenspectra method (Yip et al., 2004). This method reduces the uncertainty of the measurements for even noisy original spectra, making almost all the SDSS quasar spectra usable for our study. A few applications for black hole mass estimates are presented here. Wang et al. (2006) estimated an average radiative efficiency of 30%-35% for quasars at moderate redshift, which implies that most supermassive black holes are rotating very rapidly. Using our black hole mass estimates, we have found that their method is not independent of quasar lifetimes and thus that quasars do not necessarily have such high efficiencies. As a second application, we have investigated a claim by Steinhardt and Elvis (2009) that there exists a sub-Eddington boundary in the quasar mass-luminosity plane using the Shen et al. (2008) mass estimates. We re-calibrate the mass-scaling relations following Wang et al. (2009) with the most up-to-date reverberation estimates of black hole masses. We compare results from the original data sets with the new re-calibrated estimates of the mass-luminosity plane. We conclude that the presence of the sub-Eddington boundary in the original data of Shen et al. (2008) is likely due to biases in the mass-scaling relation and not to any physical process.

  5. Supermassive Black Hole Growth During The Peak Of Cosmic Star Formation

    NASA Astrophysics Data System (ADS)

    Ross, Nathaniel Robert

    2016-01-01

    Massive galaxies in the nearby universe all show evidence of a central Supermassive Black Hole. The black holes are seen to grow over time by accretion of gas from their host galaxy, a phenomenon referred to as an Active Galactic Nucleus. This process is believed to be fundamental to the observed correlations between black hole mass and properties of the host galaxies. We have a more limited and biased understanding of the growth of supermassive black holes in more 'typical' galaxies at z ˜ 1 -- 2. In this work, we search for Active Galactic Nuclei in a population of star-forming galaxies spanning a mass range of M* ˜ 107 -- 1012 M[special character omitted] at 0.62 < z < 2.39, during the peak of cosmic star formation and massive black hole growth. Our data are drawn from the WFC3 Infrared Spectroscopic Parallels (WISP) survey, for which we designed and implemented a suite of data analysis routines for discovering and measuring star-forming galaxies and active galactic nuclei. We find a sample of 50 active galactic nuclei, identified by their strong, rest-frame optical, emission-line ratios. We find that growing supermassive black holes in low-mass galaxies at z [special character omitted] 1 either make up a greater fraction of their galaxies' masses than those in massive galaxies, or perhaps emit a greater fraction of their energy in [O III].

  6. THE GROWTH OF THE STELLAR SEEDS OF SUPERMASSIVE BLACK HOLES

    SciTech Connect

    Johnson, Jarrett L.; Li Hui; Whalen, Daniel J.; Fryer, Chris L.

    2012-05-01

    The collapse of baryons into extremely massive stars with masses {approx}>10{sup 4} M{sub Sun} in a small fraction of protogalaxies at z {approx}> 10 is a promising candidate for the origin of supermassive black holes (SMBHs), some of which grow to a billion solar masses by z {approx} 7. We determine the maximum masses such stars can attain by accreting primordial gas. We find that at relatively low accretion rates the strong ionizing radiation of these stars limits their masses to M{sub *} {approx} 10{sup 3} M{sub Sun} ( M-dot{sub acc}/10{sup -3} M{sub Sun} yr{sup -1}){sup 8/7}, where M-dot{sub acc} is the rate at which the star gains mass. However, at the higher central infall rates usually found in numerical simulations of protogalactic collapse ({approx}>0.1 M{sub Sun} yr{sup -1}), the lifetime of the star instead limits its final mass to {approx}10{sup 6} M{sub Sun }. Furthermore, for the spherical accretion rates at which the star can grow, its ionizing radiation is confined deep within the protogalaxy, so the evolution of the star is decoupled from that of its host galaxy. Ly{alpha} emission from the surrounding H II region is trapped in these heavy accretion flows and likely reprocessed into strong Balmer series emission, which may be observable by the James Webb Space Telescope. This, strong He II {lambda}1640, and continuum emission are likely to be the key observational signatures of the progenitors of SMBHs at high redshift.

  7. 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.

  8. Supermassive Black Hole Growth and Merger Rates from Cosmological N-body Simulations

    SciTech Connect

    Micic, Miroslav; Holley-Bockelmann, Kelly; Sigurdsson, Steinn; Abel, Tom; /SLAC

    2007-10-29

    Understanding how seed black holes grow into intermediate and supermassive black holes (IMBHs and SMBHs, respectively) has important implications for the duty-cycle of active galactic nuclei (AGN), galaxy evolution, and gravitational wave astronomy. Most studies of the cosmological growth and merger history of black holes have used semianalytic models and have concentrated on SMBH growth in luminous galaxies. Using high resolution cosmological N-body simulations, we track the assembly of black holes over a large range of final masses - from seed black holes to SMBHs - over widely varying dynamical histories. We used the dynamics of dark matter halos to track the evolution of seed black holes in three different gas accretion scenarios. We have found that growth of a Sagittarius A* - size SMBH reaches its maximum mass M{sub SMBH}={approx}10{sup 6}M{sub {circle_dot}} at z{approx}6 through early gaseous accretion episodes, after which it stays at near constant mass. At the same redshift, the duty-cycle of the host AGN ends, hence redshift z=6 marks the transition from an AGN to a starburst galaxy which eventually becomes the Milky Way. By tracking black hole growth as a function of time and mass, we estimate that the IMBH merger rate reaches a maximum of R{sub max}=55 yr{sup -1} at z=11. From IMBH merger rates we calculate N{sub ULX}=7 per Milky Way type galaxy per redshift in redshift range 2 {approx}< z {approx}< 6.

  9. Editorial: Understanding the Growth of the First Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Valiante, Rosa; Schneider, Raffaella; Volonteri, Marta

    2016-08-01

    The formation, assembly history, and environmental impact of the massive black holes (BH) that are ubiquitous in the nuclei of luminous galaxies today remain some of the main unsolved problems in cosmic structure formation. In the last several years, it has become clear that quasars are not just tracers of early and recent structure formation, but that they seem to have actively influenced galaxies and clusters through feedback mechanisms that are still not well understood. The discovery of more and more numerous quasars at redshift above 6, powered by BHs with masses similar to that of their local counterparts, further complicates this scenario. This emphasises the urgent need to better understand how and when such massive objects form and grow, what is the strength and scale of their impact on the evolution of their host galaxies, and what are the main physical processes driving and regulating this co-evolution.

  10. 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.

  11. Horizon growth of supermassive black hole seeds fed with collisional dark matter

    NASA Astrophysics Data System (ADS)

    Lora-Clavijo, F. D.; Gracia-Linares, M.; Guzmán, F. S.

    2014-09-01

    We present the accretion of collisional dark matter on a supermassive black hole (SMBH) seed. The analysis is based on the numerical solution of the fully coupled system of Einstein-Euler equations for spherically symmetric flow, where the dark matter is modelled as a perfect fluid that obeys an ideal gas equation of state. As the black hole actually grows, the accretion rate of dark matter corresponds to the black hole apparent horizon growth rate. We analyse cases with infall velocity as high as 0.5c and an environment density of 100 M⊙ pc-3, which are rather extreme conditions. Being the radial flux the maximum accretion case, our results show that the accretion of an ideal gas, eventually collisional dark matter, does not contribute significantly to SMBH masses. This result favours models predicting SMBHs were formed already with supermasses. We show that despite the fact that we are solving the full general relativistic system, for the parameter space studied our results are surprisingly similar to those obtained using the Bondi formula, which somehow certifies its use as a good approximation of a fully evolving space-time with spherical symmetry at short scales at least for dark matter densities. Additionally, we study the density profile of the gas and find that the presence of SMBHs redistributes the gas near the event horizon with a cuspy profile, whereas beyond a small fraction of a parsec it is not cuspy anymore.

  12. The Supernova that Destroyed a Protogalaxy: Prompt Chemical Enrichment and Supermassive Black Hole Growth

    NASA Astrophysics Data System (ADS)

    Whalen, Daniel J.; Johnson, Jarrett L.; Smidt, Joseph; Meiksin, Avery; Heger, Alexander; Even, Wesley; Fryer, Chris L.

    2013-09-01

    The first primitive galaxies formed from accretion and mergers by z ~ 15, and were primarily responsible for cosmological reionization and the chemical enrichment of the early cosmos. But a few of these galaxies may have formed in the presence of strong Lyman-Werner UV fluxes that sterilized them of H2, preventing them from forming stars or expelling heavy elements into the intergalactic medium prior to assembly. At masses of 108 M ⊙ and virial temperatures of 104 K, these halos began to rapidly cool by atomic lines, perhaps forming 104-106 M ⊙ Pop III stars and, later, the seeds of supermassive black holes. We have modeled the explosion of a supermassive Pop III star in the dense core of a line-cooled protogalaxy with the ZEUS-MP code. We find that the supernova (SN) expands to a radius of ~1 kpc, briefly engulfing the entire galaxy, but then collapses back into the potential well of the dark matter. Fallback fully mixes the interior of the protogalaxy with metals, igniting a violent starburst and fueling the rapid growth of a massive black hole at its center. The starburst would populate the protogalaxy with stars in greater numbers and at higher metallicities than in more slowly evolving, nearby halos. The SN remnant becomes a strong synchrotron source that can be observed with eVLA and eMERLIN and has a unique signature that easily distinguishes it from less energetic SN remnants. Such explosions, and their attendant starbursts, may well have marked the birthplaces of supermassive black holes on the sky.

  13. THE SUPERNOVA THAT DESTROYED A PROTOGALAXY: PROMPT CHEMICAL ENRICHMENT AND SUPERMASSIVE BLACK HOLE GROWTH

    SciTech Connect

    Whalen, Daniel J.; Johnson, Jarrett L.; Smidt, Joseph; Meiksin, Avery; Heger, Alexander; Even, Wesley; Fryer, Chris L.

    2013-09-01

    The first primitive galaxies formed from accretion and mergers by z {approx} 15, and were primarily responsible for cosmological reionization and the chemical enrichment of the early cosmos. But a few of these galaxies may have formed in the presence of strong Lyman-Werner UV fluxes that sterilized them of H{sub 2}, preventing them from forming stars or expelling heavy elements into the intergalactic medium prior to assembly. At masses of 10{sup 8} M{sub Sun} and virial temperatures of 10{sup 4} K, these halos began to rapidly cool by atomic lines, perhaps forming 10{sup 4}-10{sup 6} M{sub Sun} Pop III stars and, later, the seeds of supermassive black holes. We have modeled the explosion of a supermassive Pop III star in the dense core of a line-cooled protogalaxy with the ZEUS-MP code. We find that the supernova (SN) expands to a radius of {approx}1 kpc, briefly engulfing the entire galaxy, but then collapses back into the potential well of the dark matter. Fallback fully mixes the interior of the protogalaxy with metals, igniting a violent starburst and fueling the rapid growth of a massive black hole at its center. The starburst would populate the protogalaxy with stars in greater numbers and at higher metallicities than in more slowly evolving, nearby halos. The SN remnant becomes a strong synchrotron source that can be observed with eVLA and eMERLIN and has a unique signature that easily distinguishes it from less energetic SN remnants. Such explosions, and their attendant starbursts, may well have marked the birthplaces of supermassive black holes on the sky.

  14. SUPERMASSIVE SEEDS FOR SUPERMASSIVE BLACK HOLES

    SciTech Connect

    Johnson, Jarrett L.; Whalen, Daniel J.; Li Hui; Holz, Daniel E.

    2013-07-10

    Recent observations of quasars powered by supermassive black holes (SMBHs) out to z {approx}> 7 constrain both the initial seed masses and the growth of the most massive black holes (BHs) in the early universe. Here we elucidate the implications of the radiative feedback from early generations of stars and from BH accretion for popular models for the formation and growth of seed BHs. We show that by properly accounting for (1) the limited role of mergers in growing seed BHs as inferred from cosmological simulations of early star formation and radiative feedback, (2) the sub-Eddington accretion rates of BHs expected at the earliest times, and (3) the large radiative efficiencies {epsilon} of the most massive BHs inferred from observations of active galactic nuclei at high redshift ({epsilon} {approx}> 0.1), we are led to the conclusion that the initial BH seeds may have been as massive as {approx}> 10{sup 5} M{sub Sun }. This presents a strong challenge to the Population III seed model, which calls for seed masses of {approx}100 M{sub Sun} and, even with constant Eddington-limited accretion, requires {epsilon} {approx}< 0.09 to explain the highest-z SMBHs in today's standard {Lambda}CDM cosmological model. It is, however, consistent with the prediction of the direct collapse scenario of SMBH seed formation, in which a supermassive primordial star forms in a region of the universe with a high molecule-dissociating background radiation field, and collapses directly into a 10{sup 4}-10{sup 6} M{sub Sun} seed BH. These results corroborate recent cosmological simulations and observational campaigns which suggest that these massive BHs were the seeds of a large fraction of the SMBHs residing in the centers of galaxies today.

  15. 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.

  16. Major galaxy mergers and the growth of supermassive black holes in quasars.

    PubMed

    Treister, Ezequiel; Natarajan, Priyamvada; Sanders, David B; Urry, C Megan; Schawinski, Kevin; Kartaltepe, Jeyhan

    2010-04-30

    Despite observed strong correlations between central supermassive black holes (SMBHs) and star formation in galactic nuclei, uncertainties exist in our understanding of their coupling. We present observations of the ratio of heavily obscured to unobscured quasars as a function of cosmic epoch up to z congruent with 3 and show that a simple physical model describing mergers of massive, gas-rich galaxies matches these observations. In the context of this model, every obscured and unobscured quasar represents two distinct phases that result from a massive galaxy merger event. Much of the mass growth of the SMBH occurs during the heavily obscured phase. These observations provide additional evidence for a causal link between gas-rich galaxy mergers, accretion onto the nuclear SMBH, and coeval star formation. PMID:20339033

  17. Close supermassive binary black holes

    NASA Astrophysics Data System (ADS)

    Gaskell, C. Martin

    2010-01-01

    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 blackhole binary (SMB). 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 1536+044 is an example of line emission from a disc. If this is correct, the lack of clear optical spectral evidence for close SMBs is significant and argues either that the merging of close SMBs 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.

  18. Probing the growth of supermassive black holes at z > 6 with LOFAR

    NASA Astrophysics Data System (ADS)

    Rhook, Kirsty J.; Haehnelt, Martin G.

    2006-12-01

    HII regions surrounding supermassive black holes (SMBHs) in an otherwise still neutral intergalactic medium (IGM) are likely to be the most easily detectable sources by future 21-cm experiments like LOFAR. We have made predictions for the size distribution of such HII regions for several physically motivated models for BH growth at high redshift and compared this to the expected LOFAR sensitivity to these sources. The number of potentially detectable HII regions does not only depend on the ionization state of the IGM and the decoupling of the spin temperature of the neutral hydrogen from the cosmic microwave background temperature, but is also strongly sensitive to the rate of growth of BHs at high redshift. If the SMBHs at redshift 6 were built up via continuous Eddington-limited accretion from low mass seed BHs at high redshift, then LOFAR is not expected to detect isolated QSO HII regions at redshifts much larger than 6, and only if the IGM is still significantly neutral. If the high-redshift growth of BHs starts with massive seed BHs and is driven by short-lived accretion events following the merging of BH hosting galaxies then the detection of HII regions surrounding SMBHs may extend to redshifts as large as 8-9 but is still very sensitive to the redshift to which the IGM remains significantly neutral. The most optimistic predictions are for a model where the SMBHs at z > 6 have grown slowly. HII regions around SMBHs may then be detected to significantly larger redshifts.

  19. Black Hole Mass Estimates and Rapid Growth of Supermassive Black Holes in Luminous z ~ 3.5 Quasars

    NASA Astrophysics Data System (ADS)

    Zuo, Wenwen; Wu, Xue-Bing; Fan, Xiaohui; Green, Richard; Wang, Ran; Bian, Fuyan

    2015-02-01

    We present new near-infrared (IR) observations of the Hβ λ4861 and Mg II λ2798 lines for 32 luminous quasars with 3.2 < z < 3.9 using the Palomar Hale 200 inch telescope and the Large Binocular Telescope. We find that the Mg II FWHM is well correlated with the Hβ FWHM, confirming itself as a good substitute for the Hβ FWHM in the black hole mass estimates. The continuum luminosity at 5100 Å well correlates with the continuum luminosity at 3000 Å and the broad emission line luminosities (Hβ and Mg II). With simultaneous near-IR spectroscopy of the Hβ and Mg II lines to exclude the influences of flux variability, we are able to evaluate the reliability of estimating black hole masses based on the Mg II line for high redshift quasars. With the reliable Hβ line based black hole mass and Eddington ratio estimates, we find that the z ~ 3.5 quasars in our sample have black hole masses 1.90 × 109 M ⊙ <~ M BH <~ 1.37 × 1010 M ⊙, with a median of ~5.14 × 109 M ⊙ and are accreting at Eddington ratios between 0.30 and 3.05, with a median of ~1.12. Assuming a duty cycle of 1 and a seed black hole mass of 104 M ⊙, we show that the z ~ 3.5 quasars in this sample can grow to their estimated black hole masses within the age of the universe at their redshifts.

  20. BLACK HOLE MASS ESTIMATES AND RAPID GROWTH OF SUPERMASSIVE BLACK HOLES IN LUMINOUS z ∼ 3.5 QUASARS

    SciTech Connect

    Zuo, Wenwen; Wu, Xue-Bing; Fan, Xiaohui; Green, Richard; Wang, Ran; Bian, Fuyan

    2015-02-01

    We present new near-infrared (IR) observations of the Hβ λ4861 and Mg II λ2798 lines for 32 luminous quasars with 3.2 < z < 3.9 using the Palomar Hale 200 inch telescope and the Large Binocular Telescope. We find that the Mg II FWHM is well correlated with the Hβ FWHM, confirming itself as a good substitute for the Hβ FWHM in the black hole mass estimates. The continuum luminosity at 5100 Å well correlates with the continuum luminosity at 3000 Å and the broad emission line luminosities (Hβ and Mg II). With simultaneous near-IR spectroscopy of the Hβ and Mg II lines to exclude the influences of flux variability, we are able to evaluate the reliability of estimating black hole masses based on the Mg II line for high redshift quasars. With the reliable Hβ line based black hole mass and Eddington ratio estimates, we find that the z ∼ 3.5 quasars in our sample have black hole masses 1.90 × 10{sup 9} M {sub ☉} ≲ M {sub BH} ≲ 1.37 × 10{sup 10} M {sub ☉}, with a median of ∼5.14 × 10{sup 9} M {sub ☉} and are accreting at Eddington ratios between 0.30 and 3.05, with a median of ∼1.12. Assuming a duty cycle of 1 and a seed black hole mass of 10{sup 4} M {sub ☉}, we show that the z ∼ 3.5 quasars in this sample can grow to their estimated black hole masses within the age of the universe at their redshifts.

  1. 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

  2. Offset active galactic nuclei as tracers of galaxy mergers and supermassive black hole growth

    SciTech Connect

    Comerford, Julia M.; Greene, Jenny E.

    2014-07-10

    Offset active galactic nuclei (AGNs) are AGNs that are in ongoing galaxy mergers, which produce kinematic offsets in the AGNs relative to their host galaxies. Offset AGNs are also close relatives of dual AGNs. We conduct a systematic search for offset AGNs in the Sloan Digital Sky Survey by selecting AGN emission lines that exhibit statistically significant line-of-sight velocity offsets relative to systemic. From a parent sample of 18,314 Type 2 AGNs at z < 0.21, we identify 351 offset AGN candidates with velocity offsets of 50 km s{sup –1} < |Δv| < 410 km s{sup –1}. When we account for projection effects in the observed velocities, we estimate that 4%-8% of AGNs are offset AGNs. We designed our selection criteria to bypass velocity offsets produced by rotating gas disks, AGN outflows, and gravitational recoil of supermassive black holes, but follow-up observations are still required to confirm our candidates as offset AGNs. We find that the fraction of AGNs that are offset candidates increases with AGN bolometric luminosity, from 0.7% to 6% over the luminosity range 43 < log (L{sub bol}) [erg s{sup –1}] <46. If these candidates are shown to be bona fide offset AGNs, then this would be direct observational evidence that galaxy mergers preferentially trigger high-luminosity AGNs. Finally, we find that the fraction of AGNs that are offset AGN candidates increases from 1.9% at z = 0.1 to 32% at z = 0.7, in step with the growth in the galaxy merger fraction over the same redshift range.

  3. Connecting galaxy and supermassive black hole growth during the last 8 billion years

    NASA Astrophysics Data System (ADS)

    Juneau, Stephanie

    It has become increasingly clear that a complete picture of galaxy evolution requires a better understanding of the role of Active Galactic Nuclei (AGN). In particular, they could be responsible for regulating star formation and galaxy growth via feedback processes. There are also competing views about the main modes of stellar growth and supermassive black hole growth in galaxies that need to be resolved. With high infrared luminosities (thus star formation rates) and a frequent occurrence of AGN, galaxies selected in the far-infrared wavebands form an ideal sample to search for a connection between AGN and star formation. The first part of this thesis contains a detailed analysis of the molecular gas properties of nearby infrared luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs). We find that the enhanced molecular gas density in the most IR-luminous systems can be explained by major galaxy mergers, and that AGN are more likely to reside in higher-density systems. While the frequent concurrence of AGN and galaxy mergers in ULIRGs was already established, this work provides a coherent framework that explains trends observed with five molecular gas tracers with a broad range of critical densities, and a comparison with simulations that reproduce observed molecular line ratios without invoking AGN-induced chemistry. The second part of the thesis presents an analysis of the AGN content of intermediate redshift galaxies (0.3 < z < 1). However, identifying complete AGN samples at these redshift is challenging because it is difficult to find X-ray weak or absorbed AGN. To alleviate this problem, we developed the Mass-Excitation (MEx) diagram, which is applicable out to redshift of ˜ 1 with existing optical spectra. It improves the overall AGN census by detecting AGN that are missed in even the most sensitive X-ray surveys. The new diagnostic was used to study the concurrence of star formation and AGN in 70 micron-selected galaxies from the Far

  4. Simulating the growth of a disk galaxy and its supermassive black hole in a cosmological context

    NASA Astrophysics Data System (ADS)

    Levine, Robyn

    Supermassive black holes (SMBHs) are ubiquitous in the centers of galaxies. Their formation and subsequent evolution is inextricably linked to that of their host galaxies, and the study of galaxy formation is incomplete without the inclusion of SMBHs. The present work seeks to understand the growth and evolution of SMBHs through their interaction with the host galaxy and its environment. In the first part of the thesis (Chap. 2 and 3), we combine a simple semi-analytic model of outflows from active galactic nuclei (AGN) with a simulated dark matter density distribution to study the impact of SMBH feedback on cosmological scales. We find that constraints can be placed on the kinetic efficiency of such feedback using observations of the filling fraction of the Ly-a forest. We also find that AGN feedback is energetic enough to redistribute baryons over cosmological distances, having potentially significant effects on the interpretation of cosmological data which are sensitive to the total matter density distribution (e.g. weak lensing). However, truly assessing the impact of AGN feedback in the universe necessitates large-dynamic range simulations with extensive treatment of baryonic physics to first model the fueling of SMBHs. In the second part of the thesis (Chap. 4-6) we use a hydrodynamic adaptive mesh refinement simulation to follow the growth and evolution of a typical disk galaxy hosting a SMBH, in a cosmological context. The simulation covers a dynamical range of 10 million allowing us to study the transport of matter and angular momentum from super-galactic scales all the way down to the outer edge of the accretion disk around the SMBH. Focusing our attention on the central few hundred parsecs of the galaxy, we find the presence of a cold, self-gravitating, molecular gas disk which is globally unstable. The global instabilities drive super-sonic turbulence, which maintains local stability and allows gas to fuel a SMBH without first fragmenting completely

  5. ENVIRONMENTAL EFFECTS ON THE GROWTH OF SUPERMASSIVE BLACK HOLES AND ACTIVE GALACTIC NUCLEUS FEEDBACK

    SciTech Connect

    Shin, Min-Su; Ostriker, Jeremiah P.; Ciotti, Luca

    2012-01-20

    We investigate how environmental effects by gas stripping alter the growth of a supermassive black hole (SMBH) and its host galaxy evolution, by means of one-dimensional hydrodynamical simulations that include both mechanical and radiative active galactic nucleus (AGN) feedback effects. By changing the truncation radius of the gas distribution (R{sub t} ), beyond which gas stripping is assumed to be effective, we simulate possible environments for satellite and central galaxies in galaxy clusters and groups. The continuous escape of gas outside the truncation radius strongly suppresses star formation, while the growth of the SMBH is less affected by gas stripping because the SMBH accretion is primarily ruled by the density of the central region. As we allow for increasing environmental effects-the truncation radius decreasing from about 410 to 50 kpc-we find that the final SMBH mass declines from about 10{sup 9} to 8 Multiplication-Sign 10{sup 8} M{sub Sun }, but the outflowing mass is roughly constant at about 2 Multiplication-Sign 10{sup 10} M{sub Sun }. There are larger changes in the mass of stars formed, which declines from about 2 Multiplication-Sign 10{sup 10} to 2 Multiplication-Sign 10{sup 9} M{sub Sun }, and the final thermal X-ray gas, which declines from about 10{sup 9} to 5 Multiplication-Sign 10{sup 8} M{sub Sun }, with increasing environmental stripping. Most dramatic is the decline in the total time that the objects would be seen as quasars, which declines from 52 Myr (for R{sub t} = 377 kpc) to 7.9 Myr (for R{sub t} = 51 kpc). The typical case might be interpreted as a red and dead galaxy having episodic cooling flows followed by AGN feedback effects resulting in temporary transitions of the overall galaxy color from red to green or to blue, with (cluster) central galaxies spending a much larger fraction of their time in the elevated state than do satellite galaxies. Our results imply that various scaling relations for elliptical galaxies, in

  6. Aspects of Supermassive Black Hole Growth in Nearby Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Lena, Davide

    Super-massive black holes (SBHs) have long been identified as the engines of active galactic nuclei (AGNs) and are now considered to play a key role in galaxy evolution. In this dissertation I present results from two observational studies conducted on nearby AGNs with the aim of furthering our understanding of SBH growth and their interplay with the host galaxies. The first study is an observational search for SBHs spatially offset from the center of their host galaxies. Such offsets can be considered signatures of gravitational recoil following the coalescence of an SBH binary system (formed in the aftermath of a galaxy merger) due to emission of gravitational waves. The study is based on a photometric analysis of fourteen nearby elliptical galaxies observed with the Hubble Space Telescope. I find that parsec-scale offsets are common. However, while these are individually consistent with residual gravitational recoil oscillations, there is a high probability that larger offsets than those actually observed should have been found in the sample as a whole. There are a number of possible explanations for this result: the galaxy merger rate may be lower than current estimates; SBH-binaries may reach the merger stage with a configuration which minimizes recoil velocities; or the SBH oscillations are more quickly damped than predicted. In the second study I use integral field spectroscopy obtained with the Gemini South telescope to investigate the kinematics of the circum-nuclear ionized gas in two active galaxies: NGC 1386, a Seyfert 2, and NGC 1365, a Seyfert 1. The goal of the study is to investigate outflows in low-luminosity AGNs, and the mechanisms channeling gas (the SBH fuel) from the inner kiloparsec down to a few tens of parsecs from the SBH. I find that the dominant kinematic components can be explained as a combination of rotation in the large-scale galactic disk and compact outflows along the axis of the AGN "radiation cone". However, in the case of NGC

  7. 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. PMID:18719276

  8. 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.

  9. 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 disk 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 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 active galactic nuclei and the rapid growth of supermassive black holes, two heretofore seemingly unrelated aspects of the physics of active galactic nuclei.

  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. The imprint of the cosmic supermassive black hole growth history on the 21 cm background radiation

    NASA Astrophysics Data System (ADS)

    Tanaka, Takamitsu L.; O'Leary, Ryan M.; Perna, Rosalba

    2016-01-01

    The redshifted 21 cm transition line of hydrogen tracks the thermal evolution of the neutral intergalactic medium (IGM) at `cosmic dawn', during the emergence of the first luminous astrophysical objects (˜100 Myr after the big bang) but before these objects ionized the IGM (˜400-800 Myr after the big bang). Because X-rays, in particular, are likely to be the chief energy courier for heating the IGM, measurements of the 21 cm signature can be used to infer knowledge about the first astrophysical X-ray sources. Using analytic arguments and a numerical population synthesis algorithm, we argue that the progenitors of supermassive black holes (SMBHs) should be the dominant source of hard astrophysical X-rays - and thus the primary driver of IGM heating and the 21 cm signature - at redshifts z ≳ 20, if (i) they grow readily from the remnants of Population III stars and (ii) produce X-rays in quantities comparable to what is observed from active galactic nuclei and high-mass X-ray binaries. We show that models satisfying these assumptions dominate over contributions to IGM heating from stellar populations, and cause the 21 cm brightness temperature to rise at z ≳ 20. An absence of such a signature in the forthcoming observational data would imply that SMBH formation occurred later (e.g. via so-called direct collapse scenarios), that it was not a common occurrence in early galaxies and protogalaxies, or that it produced far fewer X-rays than empirical trends at lower redshifts, either due to intrinsic dimness (radiative inefficiency) or Compton-thick obscuration close to the source.

  12. The Stripe 82X Multiwavelength Survey of Supermassive Black Hole Growth in Powerful AGN

    NASA Astrophysics Data System (ADS)

    Urry, C. Megan; LaMassa, Stephanie M.; Cappelluti, Nico; Ananna, Tonima; Salvato, Mara; Civano, Francesca; Marchesi, Stefano; Comastri, Andrea; Richards, Gordon T.; Glikman, Eilat; Boehringer, Hans; Brusa, Marcella; Cardamone, Carolin; Chon, Gayoung; Farrah, Duncan; Gilfanov, Marat; Green, Paul J.; Komossa, Stefanie; Lira, Paulina; Makler, Martin; Pecoraro, Robert; Ranalli, Piero; Schawinski, Kevin; Stern, Daniel K.; Treister, Ezequiel; Viero, Marco; Stripe 82X Collaboration

    2016-01-01

    Deep multiwavelength surveys over the past 15 years have told us that most black hole growth in low- to moderate-luminosity AGN is obscured, and thus not well sampled by optical or soft X-ray surveys. To study whether this also holds for high-luminosity AGN, however, requires a large volume survey (because luminous AGN are rare) that is sensitive to hard X-ray plus infrared emission out to high redshifts. Stripe 82X is exactly this survey — it adds X-ray coverage at F(0.5-10 keV) ≥ 10-15 ergs/cm^2/s to an equatorial legacy field with abundant data at other wavelengths, including far- and mid-infrared imaging (Herschel, Spitzer, WISE, UKIDSS, VHS, VICS82), deep radio imaging (VLA), deep optical imaging (SDSS, HSC, DES, CFHT), UV imaging (GALEX medium-depth), and extensive optical spectroscopy (~800 spectra per square degree). The current 31.3 deg2 X-ray catalog has 6181 unique X-ray sources, of which 88% have optical or infrared counterparts and 1842 have spectroscopic redshifts. We present the characteristics of this source population and describe our search for high-luminosity and/or high-redshift obscured quasars.

  13. Bright vigorous winds as signposts of supermassive black hole birth

    NASA Astrophysics Data System (ADS)

    Fiacconi, Davide; Rossi, Elena M.

    2016-01-01

    The formation of supermassive black holes is still an outstanding question. In the quasi-star scenario, black hole seeds experience an initial super-Eddington growth, that in less than a million years may leave a 104-105 M⊙ black hole at the centre of a protogalaxy at z ˜ 20-10. Super-Eddington accretion, however, may be accompanied by vigorous mass-loss that can limit the amount of mass that reaches the black hole. In this paper, we critically assess the impact of radiative driven winds, launched from the surface of the massive envelopes from which the black hole accretes. Solving the full wind equations coupled with the hydrostatic structure of the envelope, we find mass outflows with rates between a few tens and 104 M⊙ yr-1, mainly powered by advection luminosity within the outflow. We therefore confirm the claim by Dotan et al. that mass losses can severely affect the black hole seed early growth within a quasi-star. In particular, seeds with mass >104 M⊙ can only form within mass reservoirs ≳107 M⊙, unless they are refilled at huge rates (≳100 M⊙ yr-1). This may imply that only very massive haloes (>109 M⊙) at those redshifts can harbour massive seeds. Contrary to previous claims, these winds are expected to be relatively bright (1044-1047 erg s-1), blue (Teff ˜ 8000 K) objects, that while eluding the Hubble Space Telescope, could be observed by the James Webb Space Telescope.

  14. Cold, clumpy accretion onto an active supermassive black hole

    NASA Astrophysics Data System (ADS)

    Tremblay, Grant R.; Oonk, J. B. Raymond; Combes, Françoise; Salomé, Philippe; O'Dea, Christopher P.; Baum, Stefi A.; Voit, G. Mark; Donahue, Megan; McNamara, Brian R.; Davis, Timothy A.; McDonald, Michael A.; Edge, Alastair C.; Clarke, Tracy E.; Galván-Madrid, Roberto; Bremer, Malcolm N.; Edwards, Louise O. V.; Fabian, Andrew C.; Hamer, Stephen; Li, Yuan; Maury, Anaëlle; Russell, Helen R.; Quillen, Alice C.; Urry, C. Megan; Sanders, Jeremy S.; Wise, Michael W.

    2016-06-01

    Supermassive black holes in galaxy centres can grow by the accretion of gas, liberating energy that might regulate star formation on galaxy-wide scales. The nature of the gaseous fuel reservoirs that power black hole growth is nevertheless largely unconstrained by observations, and is instead routinely simplified as a smooth, spherical inflow of very hot gas. Recent theory and simulations instead predict that accretion can be dominated by a stochastic, clumpy distribution of very cold molecular clouds—a departure from the ‘hot mode’ accretion model—although unambiguous observational support for this prediction remains elusive. Here we report observations that reveal a cold, clumpy accretion flow towards a supermassive black hole fuel reservoir in the nucleus of the Abell 2597 Brightest Cluster Galaxy (BCG), a nearby (redshift z = 0.0821) giant elliptical galaxy surrounded by a dense halo of hot plasma. Under the right conditions, thermal instabilities produce a rain of cold clouds that fall towards the galaxy’s centre, sustaining star formation amid a kiloparsec-scale molecular nebula that is found at its core. The observations show that these cold clouds also fuel black hole accretion, revealing ‘shadows’ cast by the molecular clouds as they move inward at about 300 kilometres per second towards the active supermassive black hole, which serves as a bright backlight. Corroborating evidence from prior observations of warmer atomic gas at extremely high spatial resolution, along with simple arguments based on geometry and probability, indicate that these clouds are within the innermost hundred parsecs of the black hole, and falling closer towards it.

  15. Cold, clumpy accretion onto an active supermassive black hole.

    PubMed

    Tremblay, Grant R; Oonk, J B Raymond; Combes, Françoise; Salomé, Philippe; O'Dea, Christopher P; Baum, Stefi A; Voit, G Mark; Donahue, Megan; McNamara, Brian R; Davis, Timothy A; McDonald, Michael A; Edge, Alastair C; Clarke, Tracy E; Galván-Madrid, Roberto; Bremer, Malcolm N; Edwards, Louise O V; Fabian, Andrew C; Hamer, Stephen; Li, Yuan; Maury, Anaëlle; Russell, Helen R; Quillen, Alice C; Urry, C Megan; Sanders, Jeremy S; Wise, Michael W

    2016-06-01

    Supermassive black holes in galaxy centres can grow by the accretion of gas, liberating energy that might regulate star formation on galaxy-wide scales. The nature of the gaseous fuel reservoirs that power black hole growth is nevertheless largely unconstrained by observations, and is instead routinely simplified as a smooth, spherical inflow of very hot gas. Recent theory and simulations instead predict that accretion can be dominated by a stochastic, clumpy distribution of very cold molecular clouds--a departure from the 'hot mode' accretion model--although unambiguous observational support for this prediction remains elusive. Here we report observations that reveal a cold, clumpy accretion flow towards a supermassive black hole fuel reservoir in the nucleus of the Abell 2597 Brightest Cluster Galaxy (BCG), a nearby (redshift z = 0.0821) giant elliptical galaxy surrounded by a dense halo of hot plasma. Under the right conditions, thermal instabilities produce a rain of cold clouds that fall towards the galaxy's centre, sustaining star formation amid a kiloparsec-scale molecular nebula that is found at its core. The observations show that these cold clouds also fuel black hole accretion, revealing 'shadows' cast by the molecular clouds as they move inward at about 300 kilometres per second towards the active supermassive black hole, which serves as a bright backlight. Corroborating evidence from prior observations of warmer atomic gas at extremely high spatial resolution, along with simple arguments based on geometry and probability, indicate that these clouds are within the innermost hundred parsecs of the black hole, and falling closer towards it. PMID:27279215

  16. Bringing Black Holes Together: How Supermassive Black Hole Binaries Form and Plunge Through the Final Parsec

    NASA Astrophysics Data System (ADS)

    Holley-Bockelmann, Kelly

    2016-04-01

    Astronomers now know that supermassive black holes reside in nearly every galaxy.Though these black holes are an observational certainty, nearly every aspect of their evolution -- from their birth, to their fuel source, to their basic dynamics -- is a matter of lively debate. In principle, gas-rich major galaxy mergers can generate the central stockpile of fuel needed for a low mass central black hole seed to grow quickly into a supermassive one. During a galaxy merger, the black holes in each galaxy meet and form a supermassive binary black hole; as the binary orbit shrinks through its final parsec, it becomes the loudest gravitational wave source in the Universe and a powerful agent to sculpt the galactic center. This talk will touch on some current and ongoing work on refining our theories of how supermassive black hole binaries form, evolve within, and alter their galaxy host.

  17. 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

  18. Observational signatures of binary supermassive black holes

    SciTech Connect

    Roedig, Constanze; Krolik, Julian H.; Miller, M. Coleman

    2014-04-20

    Observations indicate that most massive galaxies contain a supermassive black hole, and theoretical studies suggest that when such galaxies have a major merger, the central black holes will form a binary and eventually coalesce. Here we discuss two spectral signatures of such binaries that may help distinguish them from ordinary active galactic nuclei. These signatures are expected when the mass ratio between the holes is not extreme and the system is fed by a circumbinary disk. One such signature is a notch in the thermal continuum that has been predicted by other authors; we point out that it should be accompanied by a spectral revival at shorter wavelengths and also discuss its dependence on binary properties such as mass, mass ratio, and separation. In particular, we note that the wavelength λ {sub n} at which the notch occurs depends on these three parameters in such a way as to make the number of systems displaying these notches ∝λ{sub n}{sup 16/3}; longer wavelength searches are therefore strongly favored. A second signature, first discussed here, is hard X-ray emission with a Wien-like spectrum at a characteristic temperature ∼100 keV produced by Compton cooling of the shock generated when streams from the circumbinary disk hit the accretion disks around the individual black holes. We investigate the observability of both signatures. The hard X-ray signal may be particularly valuable as it can provide an indicator of black hole merger a few decades in advance of the event.

  19. Supermassive black holes in galactic nuclei

    NASA Astrophysics Data System (ADS)

    Kormendy, John; Gebhardt, Karl

    2001-10-01

    We review the motivation and search for supermassive black holes (BHs) in galaxies. Energetic nuclear activity provides indirect but compelling evidence for BH engines. Ground-based dynamical searches for central dark objects are reviewed in Kormendy & Richstone (1995, ARA&A, 33, 581). Here we provide an update of results from the Hubble Space Telescope (HST). This has greatly accelerated the detection rate. As of 2001 March, dynamical BH detections are available for at least 37 galaxies. The demographics of these objects lead to the following conclusions: (1) BH mass correlates with the luminosity of the bulge component of the host galaxy, albeit with considerable scatter. The median BH mass fraction is 0.13% of the mass of the bulge. (2) BH mass correlates with the mean velocity dispersion of the bulge inside its effective radius, i.e., with how strongly the bulge stars are gravitationally bound to each other. For the best mass determinations, the scatter is consistent with the measurement errors. (3) BH mass correlates with the luminosity of the high-density central component in disk galaxies independent of whether this is a real bulge (a mini-elliptical, believed to form via a merger-induced dissipative collapse and starburst) or a ``pseudobulge'' (believed to form by inward transport of disk material). (4) BH mass does not correlate with the luminosity of galaxy disks. If pure disks contain BHs (and active nuclei imply that some do), then their masses are much smaller than 0.13% of the mass of the disk. We conclude that present observations show no dependence of BH mass on the details of whether BH feeding happens rapidly during a collapse or slowly via secular evolution of the disk. The above results increasingly support the hypothesis that the major events that form a bulge or elliptical galaxy and the main growth phases of its BH-when it shone like a quasar-were the same events. .

  20. Magnetic fields during the formation of supermassive black holes

    NASA Astrophysics Data System (ADS)

    Latif, M. A.; Schleicher, D. R. G.; Schmidt, W.

    2014-05-01

    Observations of quasars at z > 6 report the existence of a billion solar mass black holes. Comprehending their formation in such a short time-scale is a matter of ongoing research. One of the most promising scenarios to assemble supermassive black holes is a monolithic collapse of protogalactic gas clouds in atomic cooling haloes with Tvir ≥ 104 K. In this paper, we study the amplification and impact of magnetic fields during the formation of seed black holes in massive primordial haloes. We perform high-resolution cosmological magnetohydrodynamic simulations for four distinct haloes and follow their collapse for a few free-fall times until the simulations reach a peak density of 7 × 10-10 g cm-3. Our findings show that irrespective of the initial seed field, the magnetic field strength reaches a saturated state in the presence of strong accretion shocks. Under such conditions, the growth time becomes very short and amplification occurs rapidly within a small fraction of the free-fall time. We find that the presence of such strong magnetic fields provides additional support against gravity and helps in suppressing fragmentation. Massive clumps of a few hundred solar masses are formed at the end of our simulations and high accretion rates of 1 M⊙ yr-1 are observed. We expect that in the presence of such accretion rates, the clumps will grow to form supermassive stars of ˜105 M⊙. Overall, the role of the magnetic fields seems supportive for the formation of massive black holes.

  1. Relativistic Collapse of Rotating Supermassive Stars to Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Shapiro, Stuart L.

    2003-10-01

    There is compelling evidence that supermassive black holes (SMBHs) exist. Yet the origin of these objects, or their seeds, is still unknown. We are performing general relativistic simulations of gravitational collapse to black holes in different scenarios to help reveal how SMBH seeds might arise in the universe. SMBHs with ~ 109 Msolar must have formed by z > 6, or within 109 yrs after the Big Bang, to power quasars. It may be difficult for gas accretion to build up such a SMBH by this time unless the initial seed black hole already has a substantial mass. One plausible progenitor of a massive seed black hole is a supermassive star (SMS). We have followed the collapse of a SMS to a SMBH by means of 3D hydrodynamic simulations in post-Newtonian gravity and axisymmetric simulations in full general relativity. The initial SMS of arbitrary mass M in these simulations rotates uniformly at the mass-shedding limit and is marginally unstable to radial collapse. The final black hole mass and spin are determined to be Mh/M ~ 0.9 and Jh/Mh2 ~ 0.75. The remaining mass goes into a disk of mass Mdisk/M ~ 0.1. This disk arises even though the total spin of the progenitor star, J/M2 = 0.97, is safely below the Kerr limit. The collapse generates a mild burst gravitational radiation. Nonaxisymmetric bars or one-armed spirals may arise during the quasi-stationary evolution of a SMS, during its collapse, or in the ambient disk about the hole, and are potential sources of quasi-periodic waves, detectable by LISA.

  2. Hidden Pair of Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-08-01

    Could a pair of supermassive black holes (SMBHs) be lurking at the center of the galaxy Mrk 231? A recent study finds that this may be the case and the unique spectrum of this galaxy could be the key to discovering more hidden binary SMBH systems.Where Are the Binary Supermassive Black Holes?Its believed that most, if not all, galaxies have an SMBH at their centers. As two galaxies merge, the two SMBHs should evolve into a closely-bound binary system before they eventually merge. Given the abundance of galaxy mergers, we would expect to see the kinematic and visual signatures of these binary SMBHs among observed active galactic nuclei yet such evidence for sub-parsec binary SMBH systems remains scarce and ambiguous. This has led researchers to wonder: is there another way that we might detect these elusive systems?A collaboration led by Chang-Shuo Yan (National Astronomical Observatories, Chinese Academy of Sciences) thinks that there is. The group suggests that these systems might have distinct signatures in their optical-to-UV spectra, and they identify a system that might be just such a candidate: Mrk 231.A Binary CandidateProposed model of Mrk 231. Two supermassive black holes, each with their own mini-disk, orbit each other in the center of a circumbinary disk. The secondary black hole has cleared gap in the circumbinary disk as a result of its orbit around the primary black hole. [Yan et al. 2015]Mrk 231 is a galaxy with a disturbed morphology and tidal tails strong clues that it might be in the final stages of a galactic merger. In addition to these signs, Mrk 231 also has an unusual spectrum for a quasar: its continuum emission displays an unexpected drop in the near-UV band.Yan and her collaborators propose that the odd behavior of Mrk 231s spectrum can be explained if the center of the galaxy houses a pair of SMBHs each with its own mini accretion disk surrounded by a circumbinary accretion disk. As the secondary SMBH orbits the primary SMBH (with a

  3. ECCENTRIC EVOLUTION OF SUPERMASSIVE BLACK HOLE BINARIES

    SciTech Connect

    Iwasawa, Masaki; An, Sangyong; Matsubayashi, Tatsushi; Funato, Yoko; Makino, Junichiro

    2011-04-10

    In recent numerical simulations, it has been found that the eccentricity of supermassive black hole (SMBH)-intermediate black hole (IMBH) binaries grows toward unity through interactions with the stellar background. This increase of eccentricity reduces the merging timescale of the binary through the gravitational radiation to a value well below the Hubble time. It also gives a theoretical explanation of the existence of eccentric binaries such as that in OJ287. In self-consistent N-body simulations, this increase of eccentricity is always observed. On the other hand, the result of the scattering experiment between SMBH binaries and field stars indicated that the eccentricity dose not change significantly. This discrepancy leaves the high eccentricity of the SMBH binaries in N-body simulations unexplained. Here, we present a stellar-dynamical mechanism that drives the increase of the eccentricity of an SMBH binary with a large mass ratio. There are two key processes involved. The first one is the Kozai mechanism under a non-axisymmetric potential, which effectively randomizes the angular momenta of surrounding stars. The other is the selective ejection of stars with prograde orbits. Through these two mechanisms, field stars extract the orbital angular momentum of the SMBH binary. Our proposed mechanism causes the increase in the eccentricity of most of SMBH binaries, resulting in the rapid merger through gravitational wave radiation. Our result has given a definite solution to the 'last-parsec problem'.

  4. Binary pairs of supermassive black holes - Formation in merging galaxies

    NASA Astrophysics Data System (ADS)

    Valtaoja, L.; Valtonen, M. J.; Byrd, G. G.

    1989-08-01

    A process in which supermassive binary blackholes are formed in nuclei of supergiant galaxies due to galaxy mergers is examined. There is growing evidence that mergers of galaxies are common and that supermassive black holes in center of galaxies are also common. Consequently, it is expected that binary black holes should arise in connection with galaxy mergers. The merger process in a galaxy modeled after M87 is considered. The capture probability of a companion is derived as a function of its mass. Assuming a correlation between the galaxy mass and the blackholes mass, the expected mass ratio in binary black holes is calculated. The binary black holes formed in this process are long lived, surviving longer than the Hubble time unless they are perturbed by black holes from successive mergers. The properties of these binaries agree with Gaskell's (1988) observational work on quasars and its interpretation in terms of binary black holes.

  5. Dynamical Friction around Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Antonini, Fabio; Merritt, David

    2012-01-01

    The density of stars in galactic bulges is often observed to be flat or slowly rising inside the influence radius of the supermassive black hole (SMBH). Attributing the dynamical-friction force to stars moving more slowly than the test body, as is commonly done, is likely to be a poor approximation in such a core since there are no stars moving more slowly than the local circular velocity. We have tested this prediction using large-scale N-body experiments. The rate of orbital decay never drops precisely to zero, because stars moving faster than the test body also contribute to the frictional force. When the contribution from the fast-moving stars is included in the expression for the dynamical-friction force, and the changes induced by the massive body on the stellar distribution are taken into account, Chandrasekhar's theory is found to reproduce the rate of orbital decay remarkably well. However, this rate is still substantially smaller than the rate predicted by Chandrasekhar's formula in its most widely used forms, implying longer timescale for inspiral. Motivated by recent observations that suggest a parsec-scale core around the Galactic center (GC) SMBH, we investigate the evolution of a population of stellar-mass black holes (BHs) as they spiral into the center of the Galaxy. After ~10 Gyr, we find that the density of BHs can remain substantially less than the density in stars at all radii; we conclude that it would be unjustified to assume that the spatial distribution of BHs at the GC is well described by steady-state models. One consequence is that rates of capture of BHs by the SMBH at the Galactic center (extreme-mass-ratio inspirals) may be much lower than in standard models. When capture occurs, inspiraling BHs often reach the gravitational-radiation-dominated regime while on orbits that are still highly eccentric; even after the semimajor axis has decreased to values small enough for detection by space-based interferometers, eccentricities can be

  6. DYNAMICAL FRICTION AROUND SUPERMASSIVE BLACK HOLES

    SciTech Connect

    Antonini, Fabio; Merritt, David E-mail: merritt@astro.rit.edu

    2012-01-20

    The density of stars in galactic bulges is often observed to be flat or slowly rising inside the influence radius of the supermassive black hole (SMBH). Attributing the dynamical-friction force to stars moving more slowly than the test body, as is commonly done, is likely to be a poor approximation in such a core since there are no stars moving more slowly than the local circular velocity. We have tested this prediction using large-scale N-body experiments. The rate of orbital decay never drops precisely to zero, because stars moving faster than the test body also contribute to the frictional force. When the contribution from the fast-moving stars is included in the expression for the dynamical-friction force, and the changes induced by the massive body on the stellar distribution are taken into account, Chandrasekhar's theory is found to reproduce the rate of orbital decay remarkably well. However, this rate is still substantially smaller than the rate predicted by Chandrasekhar's formula in its most widely used forms, implying longer timescale for inspiral. Motivated by recent observations that suggest a parsec-scale core around the Galactic center (GC) SMBH, we investigate the evolution of a population of stellar-mass black holes (BHs) as they spiral into the center of the Galaxy. After {approx}10 Gyr, we find that the density of BHs can remain substantially less than the density in stars at all radii; we conclude that it would be unjustified to assume that the spatial distribution of BHs at the GC is well described by steady-state models. One consequence is that rates of capture of BHs by the SMBH at the Galactic center (extreme-mass-ratio inspirals) may be much lower than in standard models. When capture occurs, inspiraling BHs often reach the gravitational-radiation-dominated regime while on orbits that are still highly eccentric; even after the semimajor axis has decreased to values small enough for detection by space-based interferometers, eccentricities

  7. Simulating the Growth of a Disk Galaxy and its Supermassive Black Hole in a Cosmological Simulating the Growth of a Disk Galaxy and its Supermassive Black Hole in a Cosmological Context

    SciTech Connect

    Levine, Robyn Deborah; /JILA, Boulder

    2008-07-01

    Supermassive black holes (SMBHs) are ubiquitous in the centers of galaxies. Their formation and subsequent evolution is inextricably linked to that of their host galaxies, and the study of galaxy formation is incomplete without the inclusion of SMBHs. The present work seeks to understand the growth and evolution of SMBHs through their interaction with the host galaxy and its environment. In the first part of the thesis (Chap. 2 and 3), we combine a simple semi-analytic model of outflows from active galactic nuclei (AGN) with a simulated dark matter density distribution to study the impact of SMBH feedback on cosmological scales. We find that constraints can be placed on the kinetic efficiency of such feedback using observations of the filling fraction of the Ly{alpha} forest. We also find that AGN feedback is energetic enough to redistribute baryons over cosmological distances, having potentially significant effects on the interpretation of cosmological data which are sensitive to the total matter density distribution (e.g. weak lensing). However, truly assessing the impact of AGN feedback in the universe necessitates large-dynamic range simulations with extensive treatment of baryonic physics to first model the fueling of SMBHs. In the second part of the thesis (Chap. 4-6) we use a hydrodynamic adaptive mesh refinement simulation to follow the growth and evolution of a typical disk galaxy hosting a SMBH, in a cosmological context. The simulation covers a dynamical range of 10 million allowing us to study the transport of matter and angular momentum from super-galactic scales all the way down to the outer edge of the accretion disk around the SMBH. Focusing our attention on the central few hundred parsecs of the galaxy, we find the presence of a cold, self-gravitating, molecular gas disk which is globally unstable. The global instabilities drive super-sonic turbulence, which maintains local stability and allows gas to fuel a SMBH without first fragmenting

  8. Supermassive Black Hole Through a Magnifying Glass

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-12-01

    What happens when light from a distant quasar powered by a supermassive black hole is bent not only by a foreground galaxy, but also by individual stars within that galaxys nucleus? The neighborhood of the central black hole can be magnified, and we get a close look at the inner regions of its accretion disk!What is Microlensing?Our view of Q2237+0305 is heavily affected by a process called gravitational lensing. As evidenced by the four copies of the quasar in the image above, Q2237+0305 undergoes macrolensing, wherein the gravity of a massive foreground galaxy pulls on the light of a background object, distorting the image into arcs or multiple copies.But Q2237+0305 also undergoes an effect called microlensing. Due to the fortuitous alignment of Q2237+0305 with the nucleus of the foreground galaxy lensing it, stars within the foreground galaxy pass in front of the quasar images. As a star passes, its own gravitational pull also affects the light of the image, causing the image to brighten and/or magnify.How can we tell the difference between intrinsic brightening of Q2237+0305 and brightening due to microlensing? Brightening that occurs in all four images of the quasar is intrinsic. But if the brightening occurs in only one image, it must be caused by microlensing of that image. The timescale of this effect, which depends on how quickly the foreground galaxy moves relative to the background quasar, is on the order of a few hundred days for Q2237+0305.Resolving StructureThe light curve of a microlensed image can reveal information about the structure of the distant object. For this reason, a team of scientists led by Evencio Mediavilla (Institute of Astrophysics of the Canaries, University of La Laguna) has studied the light curves of three independent microlensing events of Q2237+0305 images.Average light curve of the three microlensing events near the peak brightness. The double-peaked structure may be due to light from the innermost region of the quasars

  9. Black Holes

    NASA Astrophysics Data System (ADS)

    Livio, Mario; Koekemoer, Anton M.

    2011-02-01

    Participants; Preface Mario Livio and Anton Koekemoer; 1. Black holes, entropy, and information G. T. Horowitz; 2. Gravitational waves from black-hole mergers J. G. Baker, W. D. Boggs, J. M. Centrella, B. J. Kelley, S. T. McWilliams and J. R. van Meter; 3. Out-of-this-world physics: black holes at future colliders G. Landsberg; 4. Black holes in globular clusters S. L. W. McMillan; 5. Evolution of massive black holes M. Volonteri; 6. Supermassive black holes in deep multiwavelength surveys C. M. Urry and E. Treister; 7. Black-hole masses from reverberation mapping B. M. Peterson and M. C. Bentz; 8. Black-hole masses from gas dynamics F. D. Macchetto; 9. Evolution of supermassive black holes A. Müller and G. Hasinger; 10. Black-hole masses of distant quasars M. Vestergaard; 11. The accretion history of supermassive black holes K. Brand and the NDWFS Boötes Survey Teams; 12. Strong field gravity and spin of black holes from broad iron lines A. C. Fabian; 13. Birth of massive black-hole binaries M. Colpi, M. Dotti, L. Mayer and S. Kazantzidis; 14. Dynamics around supermassive black holes A. Gualandris and D. Merritt; 15. Black-hole formation and growth: simulations in general relativity S. L. Shapiro; 16. Estimating the spins of stellar-mass black holes J. E. McClintock, R. Narayan and R. Shafee; 17. Stellar relaxation processes near the Galactic massive black hole T. Alexander; 18. Tidal disruptions of stars by supermassive black holes S. Gezari; 19. Where to look for radiatively inefficient accretion flows in low-luminosity AGN M. Chiaberge; 20. Making black holes visible: accretion, radiation, and jets J. H. Krolik.

  10. Supermassive black holes do not correlate with galaxy disks or pseudobulges.

    PubMed

    Kormendy, John; Bender, R; Cornell, M E

    2011-01-20

    The masses of supermassive black holes are known to correlate with the properties of the bulge components of their host galaxies. In contrast, they seem not to correlate with galaxy disks. Disk-grown 'pseudobulges' are intermediate in properties between bulges and disks; it has been unclear whether they do or do not correlate with black holes in the same way that bulges do. At stake in this issue are conclusions about which parts of galaxies coevolve with black holes, possibly by being regulated by energy feedback from black holes. Here we report pseudobulge classifications for galaxies with dynamically detected black holes and combine them with recent measurements of velocity dispersions in the biggest bulgeless galaxies. These data confirm that black holes do not correlate with disks and show that they correlate little or not at all with pseudobulges. We suggest that there are two different modes of black-hole feeding. Black holes in bulges grow rapidly to high masses when mergers drive gas infall that feeds quasar-like events. In contrast, small black holes in bulgeless galaxies and in galaxies with pseudobulges grow as low-level Seyfert galaxies. Growth of the former is driven by global processes, so the biggest black holes coevolve with bulges, but growth of the latter is driven locally and stochastically, and they do not coevolve with disks and pseudobulges. PMID:21248845

  11. Astrophysical phenomena related to supermassive black holes

    NASA Astrophysics Data System (ADS)

    Pott, Jörg-Uwe

    2006-12-01

    The thesis contains the results of my recent projects in astrophysical research. All projects aim at pushing the limits of our knowledge about the interaction between a galaxy, the fundamental building block of today's universe, and a supermassive black hole (SMBH) at its center. Over the past years a lot of observational evidence has been gathered for the current understanding, that at least a major part of the galaxies with a stellar bulge contain central SMBHs. The typical extragalactic approach consists of searching for the spectroscopic pattern of Keplerian rotation, produced by stars and gas, when orbiting a central dark mass (Kormendy & Richstone 1995). It suggests that a significant fraction of large galaxies host in their very nucleus a SMBH of millions to billions of solar masses (Kormendy & Gebhardt 2001). In the closest case, the center of our Milky Way, the most central stars, which can be imaged, were shown to move on orbits with circulation times of a few decades only, evidencing a mass and compactness of the dark counter part of the Keplerian motion, which can only be explained by a SMBH (Eckart & Genzel 1996; Ghez et al. 2000; Schödel et al. 2002). Having acknowledged the widespread existence of SMBHs the obvious next step is investigating the interaction with their environment. Although the basic property of a SMBH, which is concentrating a huge amount of mass in a ludicrously small volume defined by the Schwarzschild radius, only creates a deep gravitational trough, its existence evokes much more phenomena than simply attracting the surrounding matter. It can trigger or exacerbate star formation via tidal forces (Morris 1993). It shapes the distribution of its surrounding matter to accretion discs, which themselves release gravitational potential energy as radiation, possibly due to magnetic friction (Blandford 1995). The radiation efficiency of such active galactic nuclei (AGN) can become roughly 100 times more efficient than atomic nuclear

  12. The Early Growth of the First Black Holes

    NASA Astrophysics Data System (ADS)

    Johnson, Jarrett L.; Haardt, Francesco

    2016-03-01

    With detections of quasars powered by increasingly massive black holes at increasingly early times in cosmic history over the past decade, there has been correspondingly rapid progress made on the theory of early black hole formation and growth. Here, we review the emerging picture of how the first massive black holes formed from the primordial gas and then grew to supermassive scales. We discuss the initial conditions for the formation of the progenitors of these seed black holes, the factors dictating the initial masses with which they form, and their initial stages of growth via accretion, which may occur at super-Eddington rates. Finally, we briefly discuss how these results connect to large-scale simulations of the growth of supermassive black holes in the first billion years after the Big Bang.

  13. The early growth of the first black holes

    DOE PAGESBeta

    Johnson, Jarrett L.; Haardt, Francesco

    2016-03-04

    With detections of quasars powered by increasingly massive black holes at increasingly early times in cosmic history over the past decade, there has been correspondingly rapid progress made on the theory of early black hole formation and growth. Here, we review the emerging picture of how the first massive black holes formed from the primordial gas and then grew to supermassive scales. We discuss the initial conditions for the formation of the progenitors of these seed black holes, the factors dictating the initial masses with which they form, and their initial stages of growth via accretion, which may occur atmore » super-Eddington rates. Lastly, we briefly discuss how these results connect to large-scale simulations of the growth of supermassive black holes in the first billion years after the Big Bang.« less

  14. Supermassive black holes do not correlate with dark matter haloes of galaxies.

    PubMed

    Kormendy, John; Bender, Ralf

    2011-01-20

    Supermassive black holes have been detected in all galaxies that contain bulge components when the galaxies observed were close enough that the searches were feasible. Together with the observation that bigger black holes live in bigger bulges, this has led to the belief that black-hole growth and bulge formation regulate each other. That is, black holes and bulges coevolve. Therefore, reports of a similar correlation between black holes and the dark matter haloes in which visible galaxies are embedded have profound implications. Dark matter is likely to be non-baryonic, so these reports suggest that unknown, exotic physics controls black-hole growth. Here we show, in part on the basis of recent measurements of bulgeless galaxies, that there is almost no correlation between dark matter and parameters that measure black holes unless the galaxy also contains a bulge. We conclude that black holes do not correlate directly with dark matter. They do not correlate with galaxy disks, either. Therefore, black holes coevolve only with bulges. This simplifies the puzzle of their coevolution by focusing attention on purely baryonic processes in the galaxy mergers that make bulges. PMID:21248846

  15. Fueling Supermassive Black Holes in High-Resolution Cosmological Simulations

    NASA Astrophysics Data System (ADS)

    Levine, Robyn D.; Gnedin, N. Y.; Hamilton, A. J. S.

    2011-01-01

    The growth of supermassive black holes (SMBHs) in the centers of galaxies is a rich and complex problem, spanning a large dynamic range and depending on many physical processes. Simulating the transport of gas and angular momentum from super-galactic scales all the way down to the accretion disk requires sophisticated numerical techniques with extensive treatment of baryonic physics. We use a hydrodynamic adaptive mesh refinement simulation to follow the growth and evolution of a typical disk galaxy hosting a SMBH, in a cosmological context. We have adopted a piecemeal approach, focusing our attention on the gas dynamics in the central few hundred parsecs of the simulated galaxy (with boundary conditions provided by the larger cosmological simulation), and beginning with a simplified picture (no mergers or feedback). In this scenario, we find that the circumnuclear disk remains marginally stable against catastrophic fragmentation, allowing stochastic fueling of gas into the vicinity of the SMBH.

  16. Large Dynamic Range Simulations of Galaxies Hosting Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Levine, Robyn

    2011-08-01

    The co-evolution of supermassive black holes (SMBHs) and their host galaxies is a rich problem, spanning a large-dynamic range and depending on many physical processes. Simulating the transport of gas and angular momentum from super-galactic scales all the way down to the outer edge of the black hole's accretion disk requires sophisticated numerical techniques with extensive treatment of baryonic physics. We use a hydrodynamic adaptive mesh refinement simulation to follow the growth and evolution of a typical disk galaxy hosting an SMBH, in a cosmological context (covering a dynamical range of 10 million!). We have adopted a piecemeal approach, focusing our attention on the gas dynamics in the central few hundred parsecs of the simulated galaxy (with boundary conditions provided by the larger cosmological simulation), and beginning with a simplified picture (no mergers or feedback). In this scenario, we find that the circumnuclear disk remains marginally stable against catastrophic fragmentation, allowing stochastic fueling of gas into the vicinity of the SMBH. I will discuss the successes and the limitations of these simulations, and their future direction.

  17. 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.

  18. Spin orientation of supermassive black holes in active galaxies

    NASA Astrophysics Data System (ADS)

    Kollatschny, W.

    2003-12-01

    Accretion of gas onto a central supermassive black hole is generally accepted to be the source of the emitted energy in active galactic nuclei. The broad emission lines we observe in their optical spectra are probably formed in the wind of an accretion disk at distances of light days to light years from the central black hole. The variable fraction of the emission lines originates at typical distances of only 1 to 50 light days from the central supermassive black hole. We derived a central black hole mass of Morbital1.8+/- 0.4x 107 Msun in the Seyfert galaxy Mrk 110 assuming the broad emission lines are generated in gas clouds orbiting within an accretion disk. This figure depends on the inclination angle of the accretion disk. Here we report on the detection of gravitational redshifted emission in the variable fraction of the broad emission lines. We derive a central black hole mass of Mgrav=14.0+/- 3.0x 107 Msun. These measurements are independent on the orientation of the accretion disk. The comparison of both black hole mass estimates allows to determine the projection of the central accretion disk angle i to 21+/-5 deg in Mrk 110 and therefore the orientation of the spin axis of the central black hole. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen. This paper is dedicated to Frank Bash without whose efforts the Hobby-Eberly Telescope would not have been possible.

  19. Supermassive Black Holes: Work Horses of the Universe

    NASA Astrophysics Data System (ADS)

    McNamara, Brian

    The hot atmospheres of galaxies and clusters of galaxies arerepositories for the energy output from accreting, supermassive black holes located in the nuclei of galaxies. X-ray observations show that star formation fueled by gas condensing out of hot atmospheres is strongly suppressed by feedback from active galactic nuclei (AGN). This mechanism may solve several outstanding problems in astrophysics, including the numbers of luminous galaxies and their colors, and the excess number of hot baryons in the Universe. New data will be presented showing that some AGN may be powered by rapidly-spinning, ultra-massive black holes.

  20. Formation of discs around super-massive black hole binaries

    NASA Astrophysics Data System (ADS)

    Goicovic, Felipe G.; Cuadra, Jorge; Sesana, Alberto

    2016-02-01

    We model numerically the evolution of 104 M ⊙ turbulent molecular clouds in near-radial infall onto 106 M ⊙, equal-mass supermassive black hole binaries, using a modified version of the SPH code gadget-3. We investigate the different gas structures formed depending on the relative inclination between the binary and the cloud orbits. Our first results indicate that an aligned orbit produces mini-discs around each black hole, almost aligned with the binary; a perpendicular orbit produces misaligned mini-discs; and a counter-aligned orbit produces a circumbinary, counter-rotating ring.

  1. Astrophysical phenomena related to supermassive black holes

    NASA Astrophysics Data System (ADS)

    Pott, Jörg-Uwe

    2006-12-01

    The thesis contains the results of my recent projects in astrophysical research. All projects aim at pushing the limits of our knowledge about the interaction between a galaxy, the fundamental building block of today's universe, and a supermassive black hole (SMBH) at its center. Over the past years a lot of observational evidence has been gathered for the current understanding, that at least a major part of the galaxies with a stellar bulge contain central SMBHs. The typical extragalactic approach consists of searching for the spectroscopic pattern of Keplerian rotation, produced by stars and gas, when orbiting a central dark mass (Kormendy & Richstone 1995). It suggests that a significant fraction of large galaxies host in their very nucleus a SMBH of millions to billions of solar masses (Kormendy & Gebhardt 2001). In the closest case, the center of our Milky Way, the most central stars, which can be imaged, were shown to move on orbits with circulation times of a few decades only, evidencing a mass and compactness of the dark counter part of the Keplerian motion, which can only be explained by a SMBH (Eckart & Genzel 1996; Ghez et al. 2000; Schödel et al. 2002). Having acknowledged the widespread existence of SMBHs the obvious next step is investigating the interaction with their environment. Although the basic property of a SMBH, which is concentrating a huge amount of mass in a ludicrously small volume defined by the Schwarzschild radius, only creates a deep gravitational trough, its existence evokes much more phenomena than simply attracting the surrounding matter. It can trigger or exacerbate star formation via tidal forces (Morris 1993). It shapes the distribution of its surrounding matter to accretion discs, which themselves release gravitational potential energy as radiation, possibly due to magnetic friction (Blandford 1995). The radiation efficiency of such active galactic nuclei (AGN) can become roughly 100 times more efficient than atomic nuclear

  2. Confirming the First Supermassive Black Hole in a Dwarf Starburst Galaxy

    NASA Astrophysics Data System (ADS)

    Reines, Amy

    2011-10-01

    In the modern universe, supermassive black holes lie at the heart of most, if not all, galaxies with bulges. However, the birth and growth of the first "seed" black holes, back in the earlier universe, is observationally unconstrained. Reines et al. {2011} have recently discovered a candidate million-solar mass black hole in the bulgeless dwarf starburst galaxy Henize 2-10, offering the first opportunity to study a growing black hole in a nearby galaxy much like those in the infant universe. The case for an accreting black hole in Henize 2-10 is strong {e.g. co-spatial non-thermal radio and hard X-ray point sources}, but not watertight. Our proposal aims to confirm {or refute} the presence of this candidate black hole using STIS optical spectroscopy to trace the kinematics and ionization conditions in its immediate vicinity. Existing HST observations show a marginally resolved H-alpha knot coincident with the radio and X-ray point source, so our primary aim is to detect a compact rotating disk of ionized gas, directly yielding a black hole mass. Our secondary aim is to find evidence for AGN-related emission line signatures at the location of the H-alpha knot, and possibly along a narrow jet-like filament. Confirming the presence of a supermassive black hole in Henize 2-10 with these HST observations has immediate implications for our understanding of the birth and early evolution of the first black holes in the high-redshift universe.

  3. The Galactic Tango: The Elegant Dance of Galaxies and their Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Sherman, Sydney; Li, Yuexing; Zhu, Qirong

    2015-01-01

    For well over a decade, it has been known that a supermassive black hole resides in the center of almost every galaxy, and that these black holes strongly correlate with the stellar velocity dispersion (the MBH-σ correlation) and stellar mass (the MBH-Mhost correlation) of their hosts. The origins of these correlations, however, have yet to be determined. To explore the interplay between black holes and galaxies, we have utilized a sample of nearby spiral and elliptical galaxies as well as a sample of AGN in the redshift range z = 0-3. By examining galaxy properties such as mass, kinematics, and growth history, we have determined that these two correlations have distinct origins: the MBH-σ relation may be the result of virial equilibrium, whereas the MBH-Mhost relation may be the result of self-regulated black hole growth and star formation in galaxies. These results confirm the predictions of our previous theoretical model.

  4. A candidate sub-parsec supermassive binary black hole system.

    PubMed

    Boroson, Todd A; Lauer, Tod R

    2009-03-01

    The role of mergers in producing galaxies, together with the finding that most large galaxies harbour black holes in their nuclei, implies that binary supermassive black hole systems should be common. Here we report that the quasar SDSS J153636.22+044127.0 is a plausible example of such a system. This quasar shows two broad-line emission systems, separated in velocity by 3,500 km s(-1). A third system of unresolved absorption lines has an intermediate velocity. These characteristics are unique among known quasars. We interpret this object as a binary system of two black holes, having masses of 10(7.3) and 10(8.9) solar masses separated by approximately 0.1 parsec with an orbital period of approximately 100 years. PMID:19262667

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

    PubMed

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

    2014-06-01

    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. PMID:24899311

  6. Observational Constraints on the Nature of the First Supermassive Black Holes Seeds in the Early Universe

    NASA Astrophysics Data System (ADS)

    Treister, Ezequiel; Schawinski, Kevin; Natarajan, Priyamvada; Weigel, Anna

    2015-08-01

    We constrain the total accreted mass density in supermassive black holes at z>6, as inferred from the integrated X-ray emission in a sample of galaxy candidates selected using observed-frame optical and near-IR dropout techniques. Combining galaxy samples acquired in the Hubble Ultra Deep Field with recent deep Hubble observations of the CANDELS fields and Chandra 4 Msec observations we obtain the most restrictive current constraints on total black hole growth in the early Universe, estimating a mass density <1000M⊙Mpc-3. We further carry out a detailed study of all the individually-detected X-ray sources in the Chandra Deep Field South, finding that none of them is a good candidate to be at z>5.These results place interesting constraints on growth by accretion and imply one or more of the following: only ~20% luminous galaxies at this epoch are seeded with BHs - so seeding is inefficient; most black hole growth at early epochs happens in dusty - as yet undetected - host galaxies and/or in less-massive - also as yet undetected - galaxies; therefore a large fraction of the early black hole buildup is heavily obscured or that either most of the growth is due to radiatively inefficient accretion or due to black hole mergers at these early times. Not seeing a signal from growing black holes in high-redshift galaxies suggests that if their black holes are growing they are doing so in a veiled fashion, or they are simply not growing or perhaps most galaxies do not harbor black holes at their centers at all. These possibilities offer novel insights for high redshift seed formation models.Finally, we present the prospects to constrain the nature of the first black hole seeds in the early Universe using existing and planned space-based facilities.

  7. Collapse of a Rotating Supermassive Star to a Supermassive Black Hole: Analytic Determination of the Black Hole Mass and Spin

    NASA Astrophysics Data System (ADS)

    Shapiro, Stuart L.; Shibata, Masaru

    2002-10-01

    The collapse of a uniformly rotating, supermassive star (SMS) to a supermassive black hole (SMBH) has been followed recently by means of hydrodynamic simulations in full general relativity. The initial SMS of arbitrary mass M in these simulations rotates uniformly at the mass-shedding limit and is marginally unstable to radial collapse. The final black hole mass and spin have been determined to be Mh/M~0.9 and Jh/M2h~0.75. The remaining mass goes into a disk of mass Mdisk/M~0.1. Here we show that these black hole and disk parameters can be calculated analytically from the initial stellar density and angular momentum distribution. The analytic calculation thereby corroborates and provides a simple physical explanation for the computational discovery that SMS collapse inevitably terminates in the simultaneous formation of a SMBH and a rather substantial ambient disk. This disk arises even though the total spin of the progenitor star, J/M2=0.97, is safely below the Kerr limit. The calculation performed here applies to any marginally unstable n=3 polytrope uniformly rotating at the breakup speed, independent of stellar mass or the source of internal pressure. It illustrates how the black hole and disk parameters can be determined for the collapse of other types of stars with different initial density and rotation profiles.

  8. 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.

  9. Dynamical and Kinematic Structure of Bars with Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Valluri, Monica

    2014-05-01

    Observational studies have shown that nearly 65% of disk galaxies in the local Universe are barred. Furthermore, there is evidence that nearly every galaxy with a substantial central light concentration contains a supermassive black hole. This implies that bars frequently (or perhaps always) co-exist with supermassive black holes. Our recent studies have shown that the dynamical influence of a bar (e.g. its ability to transport angular momentum) and its orbital structure alters the observable kinematics in galactic nuclei. I will describe independent yet complementary sets of simulations that show that the effect of a bar is to increase the velocity dispersion within the effective radius on average by between 7% and 12% depending on when the black hole forms relative to the formation of the bar. This predicted effect is somewhat less than previous claims of the offset observed in data. Our investigations of the orbital structure of N-body bars (using automated orbit classification methods that rely on orbital spectral analysis) show that their self-consistent distribution functions comprise significantly fewer varieties of orbits than have previously been found in analytic bar potentials. The principle orbit families of N-body bars bear surprising similarity to those of slowly rotating triaxial potentials. Finally, the presence of a galactic bar can result in an overestimate of the stellar dynamical measurement of the black hole mass. I will present a new stellar dynamical model for the nucleus of the galaxy NGC 4151 which illustrates some of the problems associated with measuring the black hole mass in this barred Seyfert I galaxy.

  10. Never Before Seen: Two Supermassive Black Holes in Same Galaxy

    NASA Astrophysics Data System (ADS)

    2002-11-01

    For the first time, scientists have proof two supermassive black holes exist together in the same galaxy, thanks to data from NASA's Chandra X-ray Observatory. These black holes are orbiting each other and will merge several hundred million years from now, to create an even larger black hole resulting in a catastrophic event that will unleash intense radiation and gravitational waves. The Chandra image reveals that the nucleus of an extraordinarily bright galaxy, known as NGC 6240, contains not one, but two giant black holes, actively accreting material from their surroundings. This discovery shows that massive black holes can grow through mergers in the centers of galaxies, and that these enigmatic events will be detectable with future space-borne gravitational wave observatories. "The breakthrough came with Chandra's ability to clearly distinguish the two nuclei, and measure the details of the X-radiation from each nucleus," said Guenther Hasinger, of the Max Planck Institute for Extraterrestrial Physics in Germany, a coauthor of an upcoming Astrophysical Journal Letters paper describing the research. "These cosmic fingerprints revealed features characteristic of supermassive black holes -- an excess of high-energy photons from gas swirling around a black hole, and X-rays from fluorescing iron atoms in gas near black holes," he said. Previous X-ray observatories had shown that the central region produces X-rays, while radio, infrared and optical observations had detected two bright nuclei, but the nature of this region remained a mystery. Astronomers did not know the location of the X-ray source, or the nature of the two bright nuclei. "With Chandra, we hoped to determine which one, if either, of the nuclei was an active supermassive black hole," said Stefanie Komossa, also of the Max Planck Institute, lead author of the paper on NGC 6240. "Much to our surprise, we found that both were active black holes!" At a distance of about 400 million light years, NGC 6240

  11. THE SPIN OF THE SUPERMASSIVE BLACK HOLE IN NGC 3783

    SciTech Connect

    Brenneman, L. W.; Reynolds, C. S.; Trippe, M.; Mushotzky, R. F.; Nowak, M. A.; Reis, R. C.; Fabian, A. C.; Iwasawa, K.; Lee, J. C.; Miller, J. M.; Volonteri, M.; Nandra, K.

    2011-08-01

    The Suzaku AGN Spin Survey is designed to determine the supermassive black hole spin in six nearby active galactic nuclei (AGNs) via deep Suzaku stares, thereby giving us our first glimpse of the local black hole spin distribution. Here, we present an analysis of the first target to be studied under the auspices of this Key Project, the Seyfert galaxy NGC 3783. Despite complexity in the spectrum arising from a multi-component warm absorber, we detect and study relativistic reflection from the inner accretion disk. Assuming that the X-ray reflection is from the surface of a flat disk around a Kerr black hole, and that no X-ray reflection occurs within the general relativistic radius of marginal stability, we determine a lower limit on the black hole spin of a {>=} 0.88 (99% confidence). We examine the robustness of this result to the assumption of the analysis and present a brief discussion of spin-related selection biases that might affect flux-limited samples of AGNs.

  12. ALIGNMENT OF SUPERMASSIVE BLACK HOLE BINARY ORBITS AND SPINS

    SciTech Connect

    Miller, M. Coleman; Krolik, Julian H.

    2013-09-01

    Recent studies of accretion onto supermassive black hole binaries suggest that much, perhaps most, of the matter eventually accretes onto one hole or the other. If so, then for binaries whose inspiral from {approx}1 pc to {approx}10{sup -3}-10{sup -2} pc is driven by interaction with external gas, both the binary orbital axis and the individual black hole spins can be reoriented by angular momentum exchange with this gas. Here we show that, unless the binary mass ratio is far from unity, the spins of the individual holes align with the binary orbital axis in a time {approx}few-100 times shorter than the binary orbital axis aligns with the angular momentum direction of the incoming circumbinary gas; the spin of the secondary aligns more rapidly than that of the primary by a factor {approx}(m{sub 1}/m{sub 2}){sup 1/2} > 1. Thus the binary acts as a stabilizing agent, so that for gas-driven systems, the black hole spins are highly likely to be aligned (or counteraligned if retrograde accretion is common) with each other and with the binary orbital axis. This alignment can significantly reduce the recoil speed resulting from subsequent black hole merger.

  13. Catching supermassive black hole binaries without a net

    NASA Astrophysics Data System (ADS)

    Cornish, Neil J.; Porter, Edward K.

    2007-01-01

    The gravitational wave signals from coalescing Supermassive Black Hole Binaries are prime targets for the Laser Interferometer Space Antenna (LISA). With optimal data processing techniques, the LISA observatory should be able to detect black hole mergers anywhere in the Universe. The challenge is to find ways to dig the signals out of a combination of instrument noise and the large foreground from stellar mass binaries in our own galaxy. The standard procedure of matched filtering against a grid of templates can be computationally prohibitive, especially when the black holes are spinning or the mass ratio is large. Here we develop an alternative approach based on Metropolis-Hastings sampling and simulated annealing that is orders of magnitude cheaper than a grid search. For the first time, we show that it is possible to detect and characterize the signals from binary systems of Schwarzschild Black Holes that are embedded in instrument noise and a foreground containing millions of galactic binaries. Our technique is computationally efficient, robust, and applicable to both high and low signal-to-noise ratio systems.

  14. Rapidly Accreting Supergiant Protostars: Embryos of Supermassive Black Holes?

    NASA Astrophysics Data System (ADS)

    Hosokawa, Takashi; Omukai, Kazuyuki; Yorke, Harold W.

    2012-09-01

    Direct collapse of supermassive stars (SMSs) is a possible pathway for generating supermassive black holes in the early universe. It is expected that an SMS could form via very rapid mass accretion with \\dot{M}_*\\sim 0.1{--}1 \\,M_\\odot \\,yr^{-1} during the gravitational collapse of an atomic-cooling primordial gas cloud. In this paper, we study how stars would evolve under such extreme rapid mass accretion, focusing on the early evolution until the stellar mass reaches 103 M ⊙. To this end, we numerically calculate the detailed interior structure of accreting stars with primordial element abundances. Our results show that for accretion rates higher than 10-2 M ⊙ yr-1, stellar evolution is qualitatively different from that expected at lower rates. While accreting at these high rates, the star always has a radius exceeding 100 R ⊙, which increases monotonically with the stellar mass. The mass-radius relation for stellar masses exceeding ~100 M ⊙ follows the same track with R *vpropM 1/2 * in all cases with accretion rates >~ 10-2 M ⊙ yr-1 at a stellar mass of 103 M ⊙, the radius is ~= 7000 R ⊙ (sime 30 AU). With higher accretion rates, the onset of hydrogen burning is shifted toward higher stellar masses. In particular, for accretion rates exceeding \\dot{M}_*\\gtrsim 0.1 \\,M_\\odot \\,yr^{-1}, there is no significant hydrogen burning even after 103 M ⊙ have accreted onto the protostar. Such "supergiant" protostars have effective temperatures as low as T eff ~= 5000 K throughout their evolution and because they hardly emit ionizing photons, they do not create an H II region or significantly heat their immediate surroundings. Thus, radiative feedback is unable to hinder the growth of rapidly accreting stars to masses in excess of 103 M ⊙ as long as material is accreted at rates \\dot{M}_*\\gtrsim 10^{-2} \\,M_\\odot \\,yr^{-1}.

  15. Astrophysics of Super-Massive Black Hole Mergers

    NASA Technical Reports Server (NTRS)

    Schnittman, Jeremy D.

    2013-01-01

    We present here an overview of recent work in the subject of astrophysical manifestations of super-massive black hole (SMBH) mergers. This is a field that has been traditionally driven by theoretical work, but in recent years has also generated a great deal of interest and excitement in the observational astronomy community. In particular, the electromagnetic (EM) counterparts to SMBH mergers provide the means to detect and characterize these highly energetic events at cosmological distances, even in the absence of a space-based gravitational-wave observatory. In addition to providing a mechanism for observing SMBH mergers, EM counterparts also give important information about the environments in which these remarkable events take place, thus teaching us about the mechanisms through which galaxies form and evolve symbiotically with their central black holes.

  16. Collapse of a Rotating Supermassive Star to a Supermassive Black Hole: Fully Relativistic Simulations

    NASA Astrophysics Data System (ADS)

    Shibata, Masaru; Shapiro, Stuart L.

    2002-06-01

    We follow the collapse in axisymmetry of a uniformly rotating, supermassive star (SMS) to a supermassive black hole in full general relativity. The initial SMS of arbitrary mass M is marginally unstable to radial collapse and rotates at the mass-shedding limit. The collapse proceeds homologously early on and results in the appearance of an apparent horizon at the center. Although our integration terminates before final equilibrium is achieved, we determine that the final black hole will contain about 90% of the total mass of the system and will have a spin parameter J/M2~0.75. The remaining gas forms a rotating disk about the nascent hole.

  17. Episodic ejection from super-massive black holes

    NASA Astrophysics Data System (ADS)

    Saripalli, Lakshmi; Subrahmanyan, Ravi; Hunstead, Richard W.

    2007-04-01

    Episodic activity in super-massive black holes on timescales of a million years is confirmed by radio galaxies exhibiting `double-double' radio morphologies (Subrahmanyan et al, 1996; Schoenmakers et al, 2000). Spectacular examples showing a renewal of beam activity in the form of new beams emerging within relic radio lobes of previous activity have placed the phenomenon of recurrence in AGN outflows on a firm footing (Saripalli et al 2002; 2003). Using 25% of the Sydney University Molonglo Sky Survey we have compiled flux and volume limited samples of giant radio galaxies (Saripalli et al 2005) and herein we discuss the occurrence rates for the restarting of nuclear activity.

  18. Measuring the Innermost Stable Circular Orbits of Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Zalesky, L.; Chartas, G.

    2016-06-01

    We present a promising new technique (g-distribution method) for measuring the innermost stable circular orbit (ISCO), the inclination angle (i), and the spin of a supermassive black hole. The g-distribution method involves measurements of the distribution of the energy shifts of the relativistic iron line emitted from the accretion disk of a supermassive black hole that is microlensed by stars in a foreground galaxy and a comparison of the measured g-distribution with microlensing caustic simulations. The method has been applied to the gravitationally lensed quasars RX J1131-1231 (z_{s} = 0.658, z_{l} = 0.295), QJ 0158-4325 (z_{s} = 1.29, z_{l} = 0.317), and SDSS 1004+4112 (z_{s} = 1.73, z_{l} = 0.68). For RX J1131-1231 our initial results indicate an ISCO radius of < 5 gravitational radii and i < 65 degrees. Further monitoring of lensed quasars will provide tighter constraints on their inclination angles, ISCO radii, and spins.

  19. Tidal disruption as a probe for supermassive black hole binaries

    NASA Astrophysics Data System (ADS)

    Li, Shuo; Liu, Fukun; Berczik, Peter; Spurzem, Rainer

    2016-02-01

    Supermassive black hole binaries (SMBHBs) are the products of frequent galaxy mergers. It is very hard to be detected in quiescent galaxy. By using one million particle direct N-body simulations on special many-core hardware (GPU cluster), we study the dynamical co-evolution of SMBHB and its surrounding stars, specially focusing on the evolution of stellar tidal disruption event (TDE) rates before and after the coalescence of the SMBHB. We find a boosted TDE rate during the merger of the galaxies. After the coalescence of two supermassive black holes (SMBHs), the post-merger SMBH can get a kick velocity due to the anisotropic GW radiations. Our results about the recoiling SMBH, which oscillates around galactic center, show that most of TDEs are contributed by unbound stars when the SMBH passing through galactic center. In addition, the TDE light curve in SMBHB system is significantly different from the curve for single SMBH, which can be used to identify the SMBHB.

  20. Supermassive black holes: Coevolution (or not) of black holes and host galaxies

    NASA Astrophysics Data System (ADS)

    Kormendy, John

    2013-07-01

    Supermassive black holes (BHs) have been found in 75 galaxies by observing spatially resolved dynamics. The Hubble Space Telescope (HST) revolutionized BH work by advancing the subject from its `proof of concept' phase into quantitative studies of BH demographics. Most influential was the discovery of a tight correlation between BH masses M • and the velocity dispersions σ of stars in the host galaxy bulge components at radii where the stars mostly feel each other and not the BH. Together with correlations between M • and bulge luminosity, with the `missing light' that defines galaxy cores, and with numbers of globular clusters, this has led to the conclusion that BHs and bulges coevolve by regulating each other's growth. This simple picture with one set of correlations for all galaxies dominated BH work in the past decade. New results are now replacing the above, simple story with a richer and more plausible picture in which BHs correlate differently with different kinds of galaxy components. BHs with masses of 105-106 M ⊙ live in some bulgeless galaxies. So classical (merger-built) bulges are not necessary equipment for BH formation. On the other hand, while they live in galaxy disks, BHs do not correlate with galaxy disks or with disk-grown pseudobulges. They also have no special correlation with dark matter halos beyond the fact that halo gravity controls galaxy formation. This leads to the suggestion that there are two modes of BH feeding, (1) local, secular and episodic feeding of small BHs in largely bulgeless galaxies that involves too little energy feedback to drive BH-host-galaxy coevolution and (2) global feeding in major galaxy mergers that rapidly grows giant BHs in short-duration events whose energy feedback does affect galaxy formation. After these quasar-like phases, maintenance-mode BH feedback into hot, X-ray-emitting gas continues to have a primarily negative effect in preventing late-time star formation when cold gas or gas-rich galaxies

  1. A Supermassive Black Hole in a Nearby Galaxy

    NASA Astrophysics Data System (ADS)

    2001-03-01

    ISAAC Inspects the Center of Centaurus A Summary The nearby galaxy Centaurus A harbours a supermassive black hole at its centre . Using the ISAAC instrument at the ESO Very Large Telescope (VLT) , an international team of astronomers [1] has peered right through the spectacular dust lane of the peculiar galaxy Centaurus A , located approximately 11 million light-years away. They were able to probe the thin disk of gas that surrounds the very center of this galaxy. The new measurements show that the compact nucleus in the middle weighs more than 200 million solar masses ! This is too much just to be due to normal stars. The astronomers thus conclude the existence of a supermassive black hole lurking at the centre of Centaurus A . PR Photo 08a/01 : Visual image of the centre of Centaurus A . PR Photo 08b/01 : ISAAC spectrum of the centre of Centaurus A . PR Photo 08c/01 : The corresponding rotation curve from which the mass of the black hole was deduced. A well studied galaxy with a hidden center ESO PR Photo 08a/01 ESO PR Photo 08a/01 [Preview - JPEG: 352 x 400 pix - 160k] [Normal - JPEG: 704 x 800 pix - 376k] Caption : PR Photo 08a/01 shows a small area in the direction of the heavily obscured centre of the peculiar radio galaxy Centaurus A , as seen in visual light. It measures about 80 x 80 arcsec 2 , or 4400 x 4400 light-year 2 at the distance of this galaxy, and has been reproduced from exposures made with the FORS2 multi-mode instrument at the 8.2-m VLT KUEYEN telescope at Paranal. The full field may be seen in PR Photo 05b/00. Technical information about this photo is available below. The galaxy Centaurus A (NGC 5128) is one of the most studied objects in the southern sky. The unique appearance of this galaxy was already noticed by the famous British astronomer John Herschel in 1847 who catalogued the southern skies and made a comprehensive list of "nebulae". A fine photo of Centaurus A from the VLT was published last year as PR Photo 05b/00. Herschel could

  2. The formation of supermassive black holes in rapidly rotating disks

    NASA Astrophysics Data System (ADS)

    Latif, M. A.; Schleicher, D. R. G.

    2015-06-01

    Massive primordial halos exposed to moderate UV backgrounds are the potential birthplaces of supermassive black holes. In these halos, an initially isothermal collapse will occur, leading to high accretion rates of ~0.1 M⊙ yr-1. During the collapse, the gas in the interior will turn into a molecular state, and will form accretion disk in order to conserve angular momentum. We consider here the structure of such an accretion disk and the role of viscous heating in the presence of high accretion rates for a central star of 10, 100, and 104 M⊙. Our results show that the temperature in the disk increases considerably due to viscous heating, leading to a transition from the molecular to the atomic cooling phase. We found that the atomic cooling regime may extend out to several 100 AU for a 104 M⊙ central star and that it provides substantial support to stabilize the disk. It therefore favors the formation of a massive central object. The comparison of clump migration and contraction time scales shows that stellar feedback from these clumps may occur during the later stages of the evolution. Overall, viscous heating provides an important pathway to obtain an atomic gas phase within the center of the halo, and helps in the formation of very massive objects. The massive object may collapse to form a massive black hole of about ≥104 M⊙.

  3. RELATIVISTIC MERGERS OF SUPERMASSIVE BLACK HOLES AND THEIR ELECTROMAGNETIC SIGNATURES

    SciTech Connect

    Bode, Tanja; Haas, Roland; Laguna, Pablo; Shoemaker, Deirdre; Bogdanovic, Tamara

    2010-06-01

    Coincident detections of electromagnetic (EM) and gravitational wave (GW) signatures from coalescence events of supermassive black holes (SMBHs) are the next observational grand challenge. Such detections will provide the means to study cosmological evolution and accretion processes associated with these gargantuan compact objects. More generally, the observations will enable testing general relativity in the strong, nonlinear regime and will provide independent cosmological measurements to high precision. Understanding the conditions under which coincidences of EM and GW signatures arise during SMBH mergers is therefore of paramount importance. As an essential step toward this goal, we present results from the first fully general relativistic, hydrodynamical study of the late inspiral and merger of equal-mass, spinning SMBH binaries in a gas cloud. We find that variable EM signatures correlated with GWs can arise in merging systems as a consequence of shocks and accretion combined with the effect of relativistic beaming. The most striking EM variability is observed for systems where spins are aligned with the orbital axis and where orbiting black holes form a stable set of density wakes, but all systems exhibit some characteristic signatures that can be utilized in searches for EM counterparts. In the case of the most massive binaries observable by the Laser Interferometer Space Antenna, calculated luminosities imply that they may be identified by EM searches to z {approx} 1, while lower mass systems and binaries immersed in low density ambient gas can only be detected in the local universe.

  4. Collapse of differentially rotating supermassive stars: Post black hole formation

    SciTech Connect

    Saijo, Motoyuki; Hawke, Ian

    2009-09-15

    We investigate the collapse of differentially rotating supermassive stars (SMSs) by means of 3+1 hydrodynamic simulations in general relativity. We particularly focus on the onset of collapse to understand the final outcome of collapsing SMSs. We find that the estimated ratio of the mass between the black hole and the surrounding disk from the equilibrium star is roughly the same as the results from numerical simulation. This suggests that the picture of axisymmetric collapse is adequate, in the absence of nonaxisymmetric instabilities, to illustrate the final state of the collapse. We also find that quasiperiodic gravitational waves continue to be emitted after the quasinormal mode frequency has decayed. We furthermore have found that when the newly formed black hole is almost extreme Kerr, the amplitude of the quasiperiodic oscillation is enhanced during the late stages of the evolution. Geometrical features, shock waves, and instabilities of the fluid are suggested as a cause of this amplification behavior. This alternative scenario for the collapse of differentially rotating SMSs might be observable by the Laser Interferometer Space Antenna.

  5. Modeling AGN outbursts from supermassive black hole binaries

    NASA Astrophysics Data System (ADS)

    Tanaka, T.

    2012-12-01

    When galaxies merge to assemble more massive galaxies, their nuclear supermassive black holes (SMBHs) should form bound binaries. As these interact with their stellar and gaseous environments, they will become increasingly compact, culminating in inspiral and coalescence through the emission of gravitational radiation. Because galaxy mergers and interactions are also thought to fuel star formation and nuclear black hole activity, it is plausible that such binaries would lie in gas-rich environments and power active galactic nuclei (AGN). The primary difference is that these binaries have gravitational potentials that vary - through their orbital motion as well as their orbital evolution - on humanly tractable timescales, and are thus excellent candidates to give rise to coherent AGN variability in the form of outbursts and recurrent transients. Although such electromagnetic signatures would be ideally observed concomitantly with the binary's gravitational-wave signatures, they are also likely to be discovered serendipitously in wide-field, high-cadence surveys; some may even be confused for stellar tidal disruption events. I discuss several types of possible "smoking gun" AGN signatures caused by the peculiar geometry predicted for accretion disks around SMBH binaries.

  6. Star accretion onto supermassive black holes in axisymmetric galactic nuclei

    NASA Astrophysics Data System (ADS)

    Zhong, Shiyan; Berczik, Peter; Spurzem, Rainer

    2016-02-01

    Tidal Disruption (TD) of stars by supermassive central black holes from dense rotating star clusters is modeled by high-accuracy direct N-body simulation. We study the time evolution of the stellar tidal disruption rate and the origin of tidally disrupted stars. Compared with that in spherical systems, we found a higher TD rate in axisymmetric systems. The enhancement can be explained by an enlarged loss-cone in phase space which is raised from the fact that total angular momentum J is not conserved. As in the case of spherical systems, the distribution of the last apocenter distance of tidally accreted stars peaks at the classical critical radius. However, the angular distribution of the origin of the accreted stars reveals bimodal features. We show that the bimodal structure can be explained by the presence of two families of regular orbits, namely short axis tube and saucer orbits.

  7. Joint Evolution of Spinning Supermassive Black Holes and Rotating Nuclei

    NASA Astrophysics Data System (ADS)

    Merritt, David; Vasiliev, Eugene

    2015-01-01

    A rotating supermassive black hole (SBH) interacts with stars in a galactic nucleus via torques due to dragging of inertial frames. If the stars orbit preferentially about an axis that is misaligned with the SBH's spin, the SBH will experience a net torque and its spin vector will precess; individual stellar orbits also precess about the instantaneous SBH spin vector, although at different rates depending on their orbital elements. Solution of the coupled, post-Newtonian equations describing this interaction reveals two evolutionary modes: sustained precession of the SBH; and damped precession, leading to alignment of the SBH spin with the nuclear angular momentum. Beyond a certain radius, stars interact gravitationally with each other in a time shorter than the Lense-Thirring time. Long-term evolution in this case is well described as uniform precession of the SBH about the cluster's rotational axis, with a stochastic contribution due to star-star interactions.

  8. Gravitational waves from supermassive stars collapsing to a supermassive black hole

    NASA Astrophysics Data System (ADS)

    Shibata, Masaru; Sekiguchi, Yuichiro; Uchida, Haruki; Umeda, Hideyuki

    2016-07-01

    We derive the gravitational waveform from the collapse of a rapidly rotating supermassive star (SMS) core leading directly to a seed of a supermassive black hole (SMBH) in axisymmetric numerical-relativity simulations. We find that the peak strain amplitude of gravitational waves emitted during the black hole formation is ≈5 ×10-21 at the frequency f ≈5 mHz for an event at the cosmological redshift z =3 , if the collapsing SMS core is in the hydrogen-burning phase. Such gravitational waves will be detectable by space laser interferometric detectors like eLISA with signal-to-noise ratio ≈10 , if the sensitivity is as high as LISA for f =1 - 10 mHz . The detection of the gravitational wave signal will provide a potential opportunity for testing the direct-collapse scenario for the formation of a seed of SMBHs.

  9. 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. PMID:16929291

  10. Observing Supermassive Black Holes Across Cosmic Time: From Phenomenology to Physics

    NASA Astrophysics Data System (ADS)

    Merloni, Andrea

    In the last decade, a combination of high sensitivity and spatial resolution observations and of coordinated multi-wavelength surveys has revolutionized our view of extra-galactic black hole (BH) astrophysics. We now know that supermassive black holes reside in the nuclei of almost every galaxy, grow over cosmological times by accreting matter, interact and merge with each other, and in the process liberate enormous amounts of energy that influence dramatically the evolution of the surrounding gas and stars, providing a powerful self-regulatory mechanism for galaxy formation. The different energetic phenomena associated to growing black holes and Active Galactic Nuclei (AGN), their cosmological evolution and the observational techniques used to unveil them, are the subject of this chapter. In particular, I will focus my attention on the connection between the theory of high-energy astrophysical processes giving rise to the observed emission in AGN, the observable imprints they leave at different wavelengths, and the methods used to uncover them in a statistically robust way. I will show how such a combined effort of theorists and observers have led us to unveil most of the SMBH growth over a large fraction of the age of the Universe, but that nagging uncertainties remain, preventing us from fully understating the exact role of black holes in the complex process of galaxy and large-scale structure formation, assembly and evolution.

  11. Formation of supermassive black holes through fragmentation of torodial supermassive stars.

    PubMed

    Zink, Burkhard; Stergioulas, Nikolaos; Hawke, Ian; Ott, Christian D; Schnetter, Erik; Müller, Ewald

    2006-04-28

    We investigate new paths to supermassive black hole formation by considering the general relativistic evolution of a differentially rotating polytrope with a toroidal shape. We find that this polytrope is unstable to nonaxisymmetric modes, which leads to a fragmentation into self-gravitating, collapsing components. In the case of one such fragment, we apply a simplified adaptive mesh refinement technique to follow the evolution to the formation of an apparent horizon centered on the fragment. This is the first study of the onset of nonaxisymmetric dynamical instabilities of supermassive stars in full general relativity. PMID:16712210

  12. Recoiling supermassive black holes: a search in the nearby universe

    SciTech Connect

    Lena, D.; Robinson, A.; Axon, D. J.; Merritt, D.; Marconi, A.; Capetti, A.; Batcheldor, D.

    2014-11-10

    The coalescence of a binary black hole can be accompanied by a large gravitational recoil due to anisotropic emission of gravitational waves. A recoiling supermassive black hole (SBH) can subsequently undergo long-lived oscillations in the potential well of its host galaxy, suggesting that offset SBHs may be common in the cores of massive ellipticals. We have analyzed Hubble Space Telescope archival images of 14 nearby core ellipticals, finding evidence for small (≲ 10 pc) displacements between the active galactic nucleus (AGN; the location of the SBH) and the center of the galaxy (the mean photocenter) in 10 of them. Excluding objects that may be affected by large-scale isophotal asymmetries, we consider six galaxies to have detected displacements, including M87, where a displacement was previously reported by Batcheldor et al. In individual objects, these displacements can be attributed to residual gravitational recoil oscillations following a major or minor merger within the last few gigayears. For plausible merger rates, however, there is a high probability of larger displacements than those observed, if SBH coalescence took place in these galaxies. Remarkably, the AGN-photocenter displacements are approximately aligned with the radio source axis in four of the six galaxies with displacements, including three of the four having relatively powerful kiloparsec-scale jets. This suggests intrinsic asymmetries in radio jet power as a possible displacement mechanism, although approximate alignments are also expected for gravitational recoil. Orbital motion in SBH binaries and interactions with massive perturbers can produce the observed displacement amplitudes but do not offer a ready explanation for the alignments.

  13. RECOILING SUPERMASSIVE BLACK HOLES IN SPIN-FLIP RADIO GALAXIES

    SciTech Connect

    Liu, F. K.; Wang Dong; Chen Xian

    2012-02-20

    Numerical relativity simulations predict that coalescence of supermassive black hole (SMBH) binaries leads not only to a spin flip but also to a recoiling of the merger remnant SMBHs. In the literature, X-shaped radio sources are popularly suggested to be candidates for SMBH mergers with spin flip of jet-ejecting SMBHs. Here we investigate the spectral and spatial observational signatures of the recoiling SMBHs in radio sources undergoing black hole spin flip. Our results show that SMBHs in most spin-flip radio sources have mass ratio q {approx}> 0.3 with a minimum possible value q{sub min} {approx_equal} 0.05. For major mergers, the remnant SMBHs can get a kick velocity as high as 2100 km s{sup -1} in the direction within an angle {approx}< 40 Degree-Sign relative to the spin axes of remnant SMBHs, implying that recoiling quasars are biased to be with high Doppler-shifted broad emission lines while recoiling radio galaxies are biased to large apparent spatial off-center displacements. We also calculate the distribution functions of line-of-sight velocity and apparent spatial off-center displacements for spin-flip radio sources with different apparent jet reorientation angles. Our results show that the larger the apparent jet reorientation angle is, the larger the Doppler-shifting recoiling velocity and apparent spatial off-center displacement will be. We investigate the effects of recoiling velocity on the dust torus in spin-flip radio sources and suggest that recoiling of SMBHs would lead to 'dust-poor' active galactic nuclei. Finally, we collect a sample of 19 X-shaped radio objects and for each object give the probability of detecting the predicted signatures of recoiling SMBH.

  14. How well can we measure supermassive black hole spin?

    NASA Astrophysics Data System (ADS)

    Bonson, K.; Gallo, L. C.

    2016-05-01

    Being one of only two fundamental properties black holes possess, the spin of supermassive black holes (SMBHs) is of great interest for understanding accretion processes and galaxy evolution. However, in these early days of spin measurements, consistency and reproducibility of spin constraints have been a challenge. Here, we focus on X-ray spectral modelling of active galactic nuclei (AGN), examining how well we can truly return known reflection parameters such as spin under standard conditions. We have created and fit over 4000 simulated Seyfert 1 spectra each with 375±1k counts. We assess the fits with reflection fraction of R = 1 as well as reflection-dominated AGN with R = 5. We also examine the consequence of permitting fits to search for retrograde spin. In general, we discover that most parameters are overestimated when spectroscopy is restricted to the 2.5-10.0 keV regime and that models are insensitive to inner emissivity index and ionization. When the bandpass is extended out to 70 keV, parameters are more accurately estimated. Repeating the process for R = 5 reduces our ability to measure photon index (˜3 to 8 per cent error and overestimated), but increases precision in all other parameters - most notably ionization, which becomes better constrained (±45 erg cm s^{-1}) for low-ionization parameters (ξ < 200 erg cm s^{-1}). In all cases, we find the spin parameter is only well measured for the most rapidly rotating SMBHs (i.e. a > 0.8 to about ±0.10) and that inner emissivity index is never well constrained. Allowing our model to search for retrograde spin did not improve the results.

  15. Quasars: a supermassive rotating toroidal black hole interpretation

    NASA Astrophysics Data System (ADS)

    Spivey, R. J.

    2000-08-01

    A supermassive rotating toroidal black hole (TBH) is proposed as the fundamental structure of quasars and other jet-producing active galactic nuclei. Rotating protogalaxies gather matter from the central gaseous region leading to the birth of massive toroidal stars, the internal nuclear reactions of which proceed very rapidly. Once the nuclear fuel is spent, gravitational collapse produces a slender ring-shaped TBH remnant. Transitory electron and neutron degeneracy stabilized collapse phases, although possible, are unlikely owing to the large masses involved thus these events are typically the first supernovae of the host galaxies. Given time, the TBH mass increases through continued accretion by several orders of magnitude, the event horizon swells whilst the central aperture shrinks. The difference in angular velocities between the accreting matter and the TBH induces a magnetic field that is strongest in the region of the central aperture and innermost ergoregion. Owing to the presence of negative energy states when such a gravitational vortex is immersed in an electromagnetic field, circumstances are near ideal for energy extraction via non-thermal radiation including the Penrose process and superradiant scattering. This establishes a self-sustaining mechanism whereby the transport of angular momentum away from the quasar by relativistic bi-directional jets reinforces both the modulating magnetic field and the TBH/accretion disc angular velocity differential. Continued mass-capture by the TBH results in contraction of the central aperture until the TBH topology transitions to being spheroidal, extinguishing quasar behaviour. Similar mechanisms may be operating in microquasars, supernovae and sources of repeating gamma-ray bursts when neutron density or black hole tori arise. Long-term TBH stability seems to require either a negative cosmological constant, a non-stationary space-time resulting from the presence of accreting matter or the intervention of quantum

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

    NASA Astrophysics Data System (ADS)

    Greene, Jenny E.

    2012-12-01

    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 ~104-105Msolar 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.

  17. Searching with the Large Binocular Telescope for Accreting Supermassive Black Holes in Bulgeless Galaxies

    NASA Astrophysics Data System (ADS)

    Ferguson, Jason; Constantin, Anca; Satyapal, Shobita; Rothberg, Barry

    2016-01-01

    There is increasing evidence that supermassive black holes are created and evolve in bulgeless galaxies, revealing pathways for merger free, secular growth. Constraints on the fraction of bulgeless galaxies that host an AGN remain, however, extremely limited. Following the recent discovery of a large population of bulgeless galaxies with red mid-infrared colors, that are highly suggestive of heated dust by powerful accreting massive black holes, we have employed the Large Binocular Telescope to investigate the near-IR spectra of six of these systems. We present here the data and measurements of near-infrared hydrogen molecular and recombination lines. We find no evidence for broad components of the Paschen Alpha emission lines, suggesting the AGNs are either too weak or too absorbed to be detected. Based on new estimates of extinction and comparisons with optical measurements we discuss the likelihood of these systems being heavily obscured AGN or galactic nuclei with vigorous, yet dust embedded star formation.

  18. Black Hole Universe Model for Explaining GRBs, X-Ray Flares, and Quasars as Emissions of Dynamic Star-like, Massive, and Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Zhang, Tianxi

    2014-01-01

    Slightly modifying the standard big bang theory, the author has recently developed a new cosmological model called black hole universe, which is consistent with Mach’s principle, governed by Einstein’s general theory of relativity, and able to explain all observations of the universe. Previous studies accounted for the origin, structure, evolution, expansion, cosmic microwave background radiation, and acceleration of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This study investigates the emissions of dynamic black holes according to the black hole universe model and provides a self-consistent explanation for the observations of gamma ray bursts (GRBs), X-ray flares, and quasars as emissions of dynamic star-like, massive, and supermassive black holes. It is shown that a black hole, when it accretes its ambient matter or merges with other black holes, becomes dynamic. Since the event horizon of a dynamic black hole is broken, the inside hot (or high-frequency) blackbody radiation leaks out. The leakage of the inside hot blackbody radiation leads to a GRB if it is a star-like black hole, an X-ray flare if it is a massive black hole like the one at the center of the Milky Way, or a quasar if it is a supermassive black hole like an active galactic nucleus (AGN). The energy spectra and amount of emissions produced by the dynamic star-like, massive, and supermassive black holes can be consistent with the measurements of GRBs, X-ray flares, and quasars.

  19. Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies

    NASA Astrophysics Data System (ADS)

    Kormendy, John; Ho, Luis C.

    2013-08-01

    Supermassive black holes (BHs) have been found in 85 galaxies by dynamical modeling of spatially resolved kinematics. The Hubble Space Telescope revolutionized BH research by advancing the subject from its proof-of-concept phase into quantitative studies of BH demographics. Most influential was the discovery of a tight correlation between BH mass [Formula: see text] and the velocity dispersion σ of the bulge component of the host galaxy. Together with similar correlations with bulge luminosity and mass, this led to the widespread belief that BHs and bulges coevolve by regulating each other's growth. Conclusions based on one set of correlations from [Formula: see text] in brightest cluster ellipticals to [Formula: see text] in the smallest galaxies dominated BH work for more than a decade. New results are now replacing this simple story with a richer and more plausible picture in which BHs correlate differently with different galaxy components. A reasonable aim is to use this progress to refine our understanding of BH-galaxy coevolution. BHs with masses of 105-106M⊙ are found in many bulgeless galaxies. Therefore, classical (elliptical-galaxy-like) bulges are not necessary for BH formation. On the other hand, although they live in galaxy disks, BHs do not correlate with galaxy disks. Also, any [Formula: see text] correlations with the properties of disk-grown pseudobulges and dark matter halos are weak enough to imply no close coevolution. The above and other correlations of host-galaxy parameters with each other and with [Formula: see text] suggest that there are four regimes of BH feedback. (1) Local, secular, episodic, and stochastic feeding of small BHs in largely bulgeless galaxies involves too little energy to result in coevolution. (2) Global feeding in major, wet galaxy mergers rapidly grows giant BHs in short-duration, quasar-like events whose energy feedback does affect galaxy evolution. The resulting hosts are classical bulges and coreless

  20. Astronomers Dissect a Supermassive Black Hole with Natural Magnifying Glasses

    NASA Astrophysics Data System (ADS)

    2008-12-01

    Combining a double natural "magnifying glass" with the power of ESO's Very Large Telescope, astronomers have scrutinised the inner parts of the disc around a supermassive black hole 10 billion light-years away. They were able to study the disc with a level of detail a thousand times better than that of the best telescopes in the world, providing the first observational confirmation of the prevalent theoretical models of such discs. Omega Centauri ESO PR Photo 47a/08 The Einstein Cross The team of astronomers from Europe and the US studied the "Einstein Cross", a famous cosmic mirage. This cross-shaped configuration consists of four images of a single very distant source. The multiple images are a result of gravitational lensing by a foreground galaxy, an effect that was predicted by Albert Einstein as a consequence of his theory of general relativity. The light source in the Einstein Cross is a quasar approximately ten billion light-years away, whereas the foreground lensing galaxy is ten times closer. The light from the quasar is bent in its path and magnified by the gravitational field of the lensing galaxy. This magnification effect, known as "macrolensing", in which a galaxy plays the role of a cosmic magnifying glass or a natural telescope, proves very useful in astronomy as it allows us to observe distant objects that would otherwise be too faint to explore using currently available telescopes. "The combination of this natural magnification with the use of a big telescope provides us with the sharpest details ever obtained," explains Frédéric Courbin, leader of the programme studying the Einstein Cross with ESO's Very Large Telescope. In addition to macrolensing by the galaxy, stars in the lensing galaxy act as secondary lenses to produce an additional magnification. This secondary magnification is based on the same principle as macrolensing, but on a smaller scale, and since stars are much smaller than galaxies, is known as "microlensing". As the stars are

  1. Concurrent Supermassive Black Hole and Galazy Growth: Linking Environment and Nuclear Activity in Zeta Equals 2.23 H Alpha Emitters

    NASA Technical Reports Server (NTRS)

    Lehmer, B. D.; Lucy, A. B.; Alexander, D. M.; Best, P. N.; Geach, J. E.; Harrison, C. M.; Hornschemeier, A. E.; Matsuda, Y.; Mullaney, J. R.; Smail, Ian; Sobral, D.; Swinbank, A. M.

    2013-01-01

    We present results from an approximately equal 100 ks Chandra observation of the 2QZ Cluster 1004+00 structure at z = 2.23 (hereafter 2QZ Clus). 2QZ Clus was originally identified as an overdensity of four optically-selected QSOs at z = 2.23 within a 15 × 15 arcmin square region. Narrow-band imaging in the near-IR (within the K band) revealed that the structure contains an additional overdensity of 22 z = 2.23 H alpha-emitting galaxies (HAEs), resulting in 23 unique z = 2.23 HAEs/QSOs (22 within the Chandra field of view). Our Chandra observations reveal that three HAEs in addition to the four QSOs harbor powerfully accreting supermassive black holes (SMBHs), with 2-10 keV luminosities of approximately equal (8-60) × 10(exp 43) erg s(exp-1) and X-ray spectral slopes consistent with unobscured active galactic nucleus (AGN). Using a large comparison sample of 210 z = 2.23 HAEs in the Chandra-COSMOS field (C-COSMOS), we find suggestive evidence that the AGN fraction increases with local HAE galaxy density. The 2QZ Clus HAEs reside in a moderately overdense environment (a factor of approximately equal 2 times over the field), and after excluding optically-selected QSOs, we find that the AGN fraction is a factor of approximately equal 3.5(+3.8/ -2.2) times higher than C-COSMOS HAEs in similar environments. Using stacking analyses of the Chandra data and Herschel SPIRE observations at 250micrometers, we respectively estimate mean SMBH accretion rates ( M(BH)) and star formation rates (SFRs) for the 2QZ Clus and C-COSMOS samples. We find that the mean 2QZ Clus HAE stacked X-ray luminosity is QSO-like (L(2-10 keV) approximately equal [6-10] × 10(exp 43) erg s(exp -1)), and the implied M(BH)/SFR approximately equal (1.6-3.2) × 10(exp -3) is broadly consistent with the local M(BH)/Stellar Mass relation and z approximately equal 2 X-ray selected AGN. In contrast, the C-COSMOS HAEs are on average an order of magnitude less X-ray luminous and have M(BH)/SFR approximately

  2. CONCURRENT SUPERMASSIVE BLACK HOLE AND GALAXY GROWTH: LINKING ENVIRONMENT AND NUCLEAR ACTIVITY IN z = 2.23 H{alpha} EMITTERS

    SciTech Connect

    Lehmer, B. D.; Hornschemeier, A. E.; Lucy, A. B.; Alexander, D. M.; Harrison, C. M.; Mullaney, J. R.; Swinbank, A. M.; Best, P. N.; Geach, J. E.; Matsuda, Y.; Smail, Ian; Sobral, D.

    2013-03-10

    We present results from a Almost-Equal-To 100 ks Chandra observation of the 2QZ Cluster 1004+00 structure at z = 2.23 (hereafter 2QZ Clus). 2QZ Clus was originally identified as an overdensity of four optically-selected QSOs at z = 2.23 within a 15 Multiplication-Sign 15 arcmin{sup 2} region. Narrow-band imaging in the near-IR (within the K band) revealed that the structure contains an additional overdensity of 22 z = 2.23 H{alpha}-emitting galaxies (HAEs), resulting in 23 unique z = 2.23 HAEs/QSOs (22 within the Chandra field of view). Our Chandra observations reveal that three HAEs in addition to the four QSOs harbor powerfully accreting supermassive black holes (SMBHs), with 2-10 keV luminosities of Almost-Equal-To (8-60) Multiplication-Sign 10{sup 43} erg s{sup -1} and X-ray spectral slopes consistent with unobscured active galactic nucleus (AGN). Using a large comparison sample of 210 z = 2.23 HAEs in the Chandra-COSMOS field (C-COSMOS), we find suggestive evidence that the AGN fraction increases with local HAE galaxy density. The 2QZ Clus HAEs reside in a moderately overdense environment (a factor of Almost-Equal-To 2 times over the field), and after excluding optically-selected QSOs, we find that the AGN fraction is a factor of Almost-Equal-To 3.5{sup +3.8}{sub -2.2} times higher than C-COSMOS HAEs in similar environments. Using stacking analyses of the Chandra data and Herschel SPIRE observations at 250 {mu}m, we respectively estimate mean SMBH accretion rates ( M-dot{sub BH}) and star formation rates (SFRs) for the 2QZ Clus and C-COSMOS samples. We find that the mean 2QZ Clus HAE stacked X-ray luminosity is QSO-like (L{sub 2-10{sub keV}} Almost-Equal-To [6-10] Multiplication-Sign 10{sup 43} erg s{sup -1}), and the implied M-dot{sub BH}/SFR Almost-Equal-To (1.6-3.2) Multiplication-Sign 10{sup -3} is broadly consistent with the local M{sub BH}/M{sub *} relation and z Almost-Equal-To 2 X-ray selected AGN. In contrast, the C-COSMOS HAEs are on average an order

  3. Toward Precision Supermassive Black Hole Masses Using Megamaser Disks

    NASA Astrophysics Data System (ADS)

    van den Bosch, Remco C. E.; Greene, Jenny E.; Braatz, James A.; Constantin, Anca; Kuo, Cheng-Yu

    2016-03-01

    Megamaser disks provide the most precise and accurate extragalactic supermassive black hole (BH) masses. Here we describe a search for megamasers in nearby galaxies using the Green Bank Telescope (GBT). We focus on galaxies where we believe that we can resolve the gravitational sphere of influence of the BH and derive a stellar or gas dynamical measurement with optical or NIR observations. Since there are only a handful of super massive BHs that have direct BH mass measurements from more than one method, even a single galaxy with a megamaser disk and a stellar dynamical BH mass would provide necessary checks on the stellar dynamical methods. We targeted 87 objects from the Hobby-Eberly Telescope Massive Galaxy Survey, and detected no new maser disks. Most of the targeted objects are elliptical galaxies with typical stellar velocity dispersions of 250 km s-1 and distances within 130 Mpc. We discuss the implications of our non-detections, whether they imply a threshold X-ray luminosity required for masing, or possibly reflect the difficulty of maintaining a masing disk around much more massive (≳ {10}8 {M}⊙ ) BHs at a low Eddington ratio. Given the power of maser disks for probing BH accretion and demographics, we suggest that future maser searches should endeavour to remove remaining sample biases, in order to sort out the importance of these covariant effects.

  4. Uncovering Binary Supermassive Black Holes in Merging Galaxy Pairs

    NASA Astrophysics Data System (ADS)

    McNulty, Paul; Satyapal, Shobita; Ellison, Sara L.; Secrest, Nathan; Gliozzi, Mario; Rothberg, Barry

    2016-01-01

    It is now well known that virtually all galaxies host a central supermassive black hole (SMBH) and that galaxy interactions are ubiquitous. Theory predicts these interactions would funnel gas toward the central regions of galaxies, potentially triggering gas accretion onto the SMBH, causing them to appear as binary active galactic nuclei (AGN). However, despite decades of searching and strong theoretical reasons that they should exist, observationally confirmed cases of binary AGNs are extremely rare, and most have been discovered serendipitously. Since galaxy mergers are likely to be characterized by dusty environments, it is possible that the optical signatures of a significant number of binary AGNs are obscured. Observations from the Wide-field Infrared Survey Explorer (WISE) may hold the key for increasing the rate of discovery of binary AGN in late-stage mergers. Starting with a sample of ~4,000 galaxy pairs, we searched for mid-IR signatures of binary AGNs. In this poster, we report on the detection frequency of binary AGNs identified through mid-infrared observations and explore its dependence on merger stage.

  5. A DISPLACED SUPERMASSIVE BLACK HOLE IN M87

    SciTech Connect

    Batcheldor, D.; Perlman, E. S.; Robinson, A.; Merritt, D.; Axon, D. J.

    2010-07-01

    Isophotal analysis of M87, using data from the Advanced Camera for Surveys, reveals a projected displacement of 6.8 {+-} 0.8 pc ({approx}0.''1) between the nuclear point source (presumed to be the location of the supermassive black hole, SMBH) and the photo-center of the galaxy. The displacement is along a position angle of 307{sup 0} {+-} 17{sup 0} and is consistent with the jet axis. This suggests the active SMBH in M87 does not currently reside at the galaxy center of mass, but is displaced in the counter-jet direction. Possible explanations for the displacement include orbital motion of an SMBH binary, gravitational perturbations due to massive objects (e.g., globular clusters), acceleration by an asymmetric or intrinsically one-sided jet, and gravitational recoil resulting from the coalescence of an SMBH binary. The displacement direction favors the latter two mechanisms. However, jet asymmetry is only viable, at the observed accretion rate, for a jet age of >0.1 Gyr and if the galaxy restoring force is negligible. This could be the case in the low-density core of M87. A moderate recoil {approx}1 Myr ago might explain the disturbed nature of the nuclear gas disk, could be aligned with the jet axis, and can produce the observed offset. Alternatively, the displacement could be due to residual oscillations resulting from a large recoil that occurred in the aftermath of a major merger {<=}1 Gyr ago.

  6. The Origin and Detection of High-Redshift Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Haiman, Zoltán

    2010-11-01

    Supermassive black holes (SMBHs) are common in local galactic nuclei, and SMBHs as massive as several billion solar masses already exist at redshift z = 6. These earliest SMBHs may arise by the combination of Eddington-limited growth and mergers of stellar-mass seed BHs left behind by the first generation of metal-free stars, or by the rapid direct collapse of gas in rare special environments where the gas can avoid fragmenting into stars. In this contribution, I review these two competing scenarios. I also briefly mention some more exotic ideas and how the different models may be distinguished in the future by LISA and other instruments.

  7. Observing the dynamics of supermassive black hole binaries with pulsar timing arrays.

    PubMed

    Mingarelli, C M F; Grover, K; Sidery, T; Smith, R J E; Vecchio, A

    2012-08-24

    Pulsar timing arrays are a prime tool to study unexplored astrophysical regimes with gravitational waves. Here, we show that the detection of gravitational radiation from individually resolvable supermassive black hole binary systems can yield direct information about the masses and spins of the black holes, provided that the gravitational-wave-induced timing fluctuations both at the pulsar and at Earth are detected. This in turn provides a map of the nonlinear dynamics of the gravitational field and a new avenue to tackle open problems in astrophysics connected to the formation and evolution of supermassive black holes. We discuss the potential, the challenges, and the limitations of these observations. PMID:23002736

  8. The coevolution of galaxies and supermassive black holes: a local perspective.

    PubMed

    Heckman, Timothy M; Kauffmann, Guinevere

    2011-07-01

    One of the most fascinating discoveries in the past decade was that galaxies typically contain a centrally located black hole with a mass that is millions or even billions of times that of the Sun. There is now compelling evidence that we cannot understand how galaxies formed and evolved without understanding the life cycles of these supermassive black holes (and vice versa). We summarize the current understanding of this coevolution of galaxies and supermassive black holes (based largely on observations of the local, present-day universe) and describe prospects for the future. PMID:21737734

  9. Formation and coalescence of cosmological supermassive-black-hole binaries in supermassive-star collapse.

    PubMed

    Reisswig, C; Ott, C D; Abdikamalov, E; Haas, R; Mösta, P; Schnetter, E

    2013-10-11

    We study the collapse of rapidly rotating supermassive stars that may have formed in the early Universe. By self-consistently simulating the dynamics from the onset of collapse using three-dimensional general-relativistic hydrodynamics with fully dynamical spacetime evolution, we show that seed perturbations in the progenitor can lead to the formation of a system of two high-spin supermassive black holes, which inspiral and merge under the emission of powerful gravitational radiation that could be observed at redshifts z is approximately equal or > to 10 with the DECIGO or Big Bang Observer gravitational-wave observatories, assuming supermassive stars in the mass range 10(4)-10(6)M[symbol: see text]. The remnant is rapidly spinning with dimensionless spin a*=0.9. The surrounding accretion disk contains ~10% of the initial mass. PMID:24160586

  10. Music from the heavens - Gravitational waves from supermassive black hole mergers in the EAGLE simulations

    NASA Astrophysics Data System (ADS)

    Salcido, Jaime; Bower, Richard G.; Theuns, Tom; McAlpine, Stuart; Schaller, Matthieu; Crain, Robert A.; Schaye, Joop; Regan, John

    2016-08-01

    We estimate the expected event rate of gravitational wave signals from mergers of supermassive black holes that could be resolved by a space-based interferometer, such as the Evolved Laser Interferometer Space Antenna (eLISA), utilising the reference cosmological hydrodynamical simulation from the EAGLE suite. These simulations assume a ΛCDM cosmogony with state-of-the-art subgrid models for radiative cooling, star formation, stellar mass loss, and feedback from stars and accreting black holes. They have been shown to reproduce the observed galaxy population with unprecedented fidelity. We combine the merger rates of supermassive black holes in EAGLE with the latest phenomenological waveform models to calculate the gravitational waves signals from the intrinsic parameters of the merging black holes. The EAGLE models predict ˜2 detections per year by a gravitational wave detector such as eLISA. We find that these signals are largely dominated by mergers between seed mass black holes merging at redshifts between z ˜ 2 and z ˜ 1. In order to investigate the dependence on the assumed black hole seed mass, we introduce an additional model with a black hole seed mass an order of magnitude smaller than in our reference model. We also consider a variation of the reference model where a prescription for the expected delays in the black hole merger timescale has been included after their host galaxies merge. We find that the merger rate is similar in all models, but that the initial black hole seed mass could be distinguished through their detected gravitational waveforms. Hence, the characteristic gravitational wave signals detected by eLISA will provide profound insight into the origin of supermassive black holes and the initial mass distribution of black hole seeds.

  11. Discovery of a Supermassive Black Hole in a Bulge-less Galaxy

    NASA Astrophysics Data System (ADS)

    Mathur, Smita; Ghosh, H.; Fiore, F.; Ferrarese, L.

    2010-03-01

    Recent observational and theoretical work suggest that every galaxy hosts a supermassive black hole in its nucleus and that the mass of the black hole depends upon the mass of the galactic bulge. We initiated a program to look for accreting supermassive black holes in centers of normal (i.e. inactive) galaxies. We detected several X-ray sources in our Chandra survey, but it was difficult to separate supermassive black holes from contaminants such as X-ray binaries. We obtained XMM spectra with the goal of identifying Chandra sources. We have now analyzed one spectrum which shows the source to be reflection dominated, and almost certainly an active galactic nucleus. The importance of this result is that we seem to have discovered a supermassive black hole in a bulge-less galaxy. This is completely contrary to the expectations based on the MBH--sigma relation and implies that a bulge is not necessary for the existence of a supermassive black hole in the nucleus of a galaxy. The BH mass may be related to the dark matter halo instead. (We are working on confirming our initial result. We have also started to analyze one more XMM spectrum. Results will be ready before the HEAD meeting.)

  12. The light up and early evolution of high redshift Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Comastri, Andrea; Brusa, Marcella; Aird, James; Lanzuisi, Giorgio

    2016-07-01

    The known AGN population at z > 6 is made by luminous optical QSO hosting Supermassive Black Holes (M > 10 ^{9}solar masses), likely to represent the tip of the iceberg of the luminosity and mass function. According to theoretical models for structure formation, Massive Black Holes (M _{BH} 10^{4-7} solar masses) are predicted to be abundant in the early Universe (z > 6). The majority of these lower luminosity objects are expected to be obscured and severely underepresented in current optical near-infrared surveys. The detection of such a population would provide unique constraints on the Massive Black Holes formation mechanism and subsequent growth and is within the capabilities of deep and large area ATHENA surveys. After a summary of the state of the art of present deep XMM and Chandra surveys, at z >3-6 also mentioning the expectations for the forthcoming eROSITA all sky survey; I will present the observational strategy of future multi-cone ATHENA Wide Field Imager (WFI) surveys and the expected breakthroughs in the determination of the luminosity function and its evolution at high (> 4) and very high (>6) redshifts.

  13. Accretion and Feedback Processes in Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Zubovas, Kastytis

    2012-10-01

    Supermassive black holes (SMBHs) have been gradually recognised as important elements of galaxy and cosmic structure evolution. Their connection with the large-scale environment is maintained via feedback processes - communication of a fraction of the accretion luminosity to the host galaxy. Feedback is conjectured to expel gas from galaxies, quench star formation and establish the observed correlations between SMBH mass and host galaxy properties. Efficient feedback requires rapid gas accretion and is therefore usually investigated within the context of quasar activity phases in SMBH evolution. In this Thesis, I investigate several implications of an SMBH wind feedback model, advancing our understanding of feedback processes and the immediate environment of SMBHs. I consider analytically the large-scale outflows and their observable properties. I find that rapidly accreting SMBHs may sweep galaxies clear of gas, turning them into red-and-dead spheroids. I apply the same feedback model to our Galaxy. Its SMBH, Sgr A*, is currently exceptionally quiescent, although it must have been more active in the past in order to have grown to its present size. I investigate, both analytically and numerically, a short burst of activity which may have occurred ∼ 6 million years ago, producing an outflow which formed two large γ-ray emitting bubbles perpendicular to the Galactic plane. The results show that dynamical footprints of outflows may persist for a long time and provide evidence of past AGN activity in quiescent galaxies. I also present a model for the short-timescale flares observed daily in Sgr A*, based on tidal disruption and evaporation of asteroids in the vicinity of the SMBH. The model explains some observed flare properties, and thus improves our understanding of the processes occurring close to the SMBH. It also provides predictions for observable effects as the quiescent luminosity of Sgr A* varies on long timescales.

  14. Direct formation of supermassive black holes via multi-scale gas inflows in galaxy mergers.

    PubMed

    Mayer, L; Kazantzidis, S; Escala, A; Callegari, S

    2010-08-26

    Observations of distant quasars indicate that supermassive black holes of billions of solar masses already existed less than a billion years after the Big Bang. Models in which the 'seeds' of such black holes form by the collapse of primordial metal-free stars cannot explain the rapid appearance of these supermassive black holes because gas accretion is not sufficiently efficient. Alternatively, these black holes may form by direct collapse of gas within isolated protogalaxies, but current models require idealized conditions, such as metal-free gas, to prevent cooling and star formation from consuming the gas reservoir. Here we report simulations showing that mergers between massive protogalaxies naturally produce the conditions for direct collapse into a supermassive black hole with no need to suppress cooling and star formation. Merger-driven gas inflows give rise to an unstable, massive nuclear gas disk of a few billion solar masses, which funnels more than 10(8) solar masses of gas to a sub-parsec-scale gas cloud in only 100,000 years. The cloud undergoes gravitational collapse, which eventually leads to the formation of a massive black hole. The black hole can subsequently grow to a billion solar masses on timescales of about 10(8) years by accreting gas from the surrounding disk. PMID:20740009

  15. Energy input from quasars regulates the growth and activity of black holes and their host galaxies.

    PubMed

    Di Matteo, Tiziana; Springel, Volker; Hernquist, Lars

    2005-02-10

    In the early Universe, while galaxies were still forming, black holes as massive as a billion solar masses powered quasars. Supermassive black holes are found at the centres of most galaxies today, where their masses are related to the velocity dispersions of stars in their host galaxies and hence to the mass of the central bulge of the galaxy. This suggests a link between the growth of the black holes and their host galaxies, which has indeed been assumed for a number of years. But the origin of the observed relation between black hole mass and stellar velocity dispersion, and its connection with the evolution of galaxies, have remained unclear. Here we report simulations that simultaneously follow star formation and the growth of black holes during galaxy-galaxy collisions. We find that, in addition to generating a burst of star formation, a merger leads to strong inflows that feed gas to the supermassive black hole and thereby power the quasar. The energy released by the quasar expels enough gas to quench both star formation and further black hole growth. This determines the lifetime of the quasar phase (approaching 100 million years) and explains the relationship between the black hole mass and the stellar velocity dispersion. PMID:15703739

  16. 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.

  17. Black Holes Lead Galaxy Growth, New Research Shows

    NASA Astrophysics Data System (ADS)

    2009-01-01

    Astronomers may have solved a cosmic chicken-and-egg problem -- the question of which formed first in the early Universe -- galaxies or the supermassive black holes seen at their cores. "It looks like the black holes came first. The evidence is piling up," said Chris Carilli, of the National Radio Astronomy Observatory (NRAO). Carilli outlined the conclusions from recent research done by an international team studying conditions in the first billion years of the Universe's history in a lecture presented to the American Astronomical Society's meeting in Long Beach, California. Gas in Distant Galaxy VLA image (right) of gas in young galaxy seen as it was when the Universe was only 870 million years old. CREDIT: NRAO/AUI/NSF, SDSS Full-size JPEG, 323 KB PDF file, 180 KB Galaxy image, no annotation, JPEG 21 KB Earlier studies of galaxies and their central black holes in the nearby Universe revealed an intriguing linkage between the masses of the black holes and of the central "bulges" of stars and gas in the galaxies. The ratio of the black hole and the bulge mass is nearly the same for a wide range of galactic sizes and ages. For central black holes from a few million to many billions of times the mass of our Sun, the black hole's mass is about one one-thousandth of the mass of the surrounding galactic bulge. "This constant ratio indicates that the black hole and the bulge affect each others' growth in some sort of interactive relationship," said Dominik Riechers, of Caltech. "The big question has been whether one grows before the other or if they grow together, maintaining their mass ratio throughout the entire process." In the past few years, scientists have used the National Science Foundation's Very Large Array radio telescope and the Plateau de Bure Interferometer in France to peer far back in the 13.7 billion-year history of the Universe, to the dawn of the first galaxies. "We finally have been able to measure black-hole and bulge masses in several galaxies seen

  18. Understanding the build-up of supermassive black holes and galaxies

    NASA Astrophysics Data System (ADS)

    Carrera, Francisco; Ueda, Yoshihiro; Georgakakis, Antonis

    2016-07-01

    One of the main open questions in modern Astrophysics is understanding the coupled growth of supermassive black holes by accretion and their host galaxies via star formation, from their peak at redshifts z~ 1-4 to the present time. The generic scenario proposed involves an early phase of intense black hole growth that takes place behind large obscuring columns of inflowing dust and gas clouds. It is postulated that this is followed by a blow-out stage during which some form of AGN feedback controls the fate of the interstellar medium and hence, the evolution of the galaxy. X-rays are essential for testing this scenario as they uniquely probe AGN at both the early heavily obscured stage and the later blow-out phase. X-ray spectral analysis can identify the smoking gun evidence of heavily obscured black hole growth (e.g. intense iron Kalpha line). It therefore provides the most robust method for compiling clean samples of deeply shrouded AGN with well-defined selection functions and unbiased determinations of their intrinsic properties (accretion luminosity, obscuring column). X-rays are also the best window for studying in detail AGN feedback. This process ultimately originates in the innermost regions close to the supermassive black hole and is dominated, in terms of energy and mass flux, by highly ionisedmaterial that remains invisible at other wavelengths. The most important epoch for investigating the relation between AGN and galaxies is the redshift range z~1-4, when most black holes and stars we see in the present-day Universe were put in place. Unfortunately, exhaustive efforts with current high-energy telescopes only scrape the tip of the iceberg of the most obscured AGN population. Moreover, Xray studies of the incidence, nature and energetics of AGN feedback are limited to the local Universe. The Athena observatory will provide the technological leap required for a breakthrough in our understanding of AGN and galaxy evolution at the heyday of the Universe

  19. 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

  20. Constraints on individual supermassive black hole binaries from pulsar timing array limits on continuous gravitational waves

    NASA Astrophysics Data System (ADS)

    Schutz, Katelin; Ma, Chung-Pei

    2016-06-01

    Pulsar timing arrays (PTAs) are placing increasingly stringent constraints on the strain amplitude of continuous gravitational waves emitted by supermassive black hole binaries on subparsec scales. In this paper, we incorporate independent information about the dynamical masses Mbh of supermassive black holes in specific galaxies at known distances and use this additional information to further constrain whether or not those galaxies could host a detectable supermassive black hole binary. We estimate the strain amplitudes from individual binaries as a function of binary mass ratio for two samples of nearby galaxies: (1) those with direct dynamical measurements of Mbh in the literature, and (2) the 116 most massive early-type galaxies (and thus likely hosts of the most massive black holes) within 108 Mpc from the MASSIVE Survey. Our exploratory analysis shows that the current PTA upper limits on continuous waves (as a function of angular position in the sky) can already constrain the mass ratios of hypothetical black hole binaries in many galaxies in our samples. The constraints are stronger for galaxies with larger Mbh and at smaller distances. For the black holes with Mbh ≳ 5 × 109 M⊙ at the centres of NGC 1600, NGC 4889, NGC 4486 (M87), and NGC 4649 (M60), any binary companion in orbit within the PTA frequency bands would have to have a mass ratio of a few per cent or less.

  1. UNLEASHING POSITIVE FEEDBACK: LINKING THE RATES OF STAR FORMATION, SUPERMASSIVE BLACK HOLE ACCRETION, AND OUTFLOWS IN DISTANT GALAXIES

    SciTech Connect

    Silk, Joseph

    2013-08-01

    Pressure-regulated star formation is a simple variant on the usual supernova-regulated star formation efficiency that controls the global star formation rate as a function of cold gas content in star-forming galaxies, and accounts for the Schmidt-Kennicutt law in both nearby and distant galaxies. Inclusion of active galactic nucleus (AGN) induced pressure, by jets and/or winds that flow back onto a gas-rich disk, can lead, under some circumstances, to significantly enhanced star formation rates, especially at high redshift and most likely followed by the more widely accepted phase of star formation quenching. Simple expressions are derived that relate supermassive black hole growth, star formation, and outflow rates. The ratios of black hole to spheroid mass and of both black hole accretion and outflow rates to star formation rate are predicted as a function of time. I suggest various tests of the AGN-triggered star formation hypothesis.

  2. Tidal disruption of a star by a supermassive black hole

    SciTech Connect

    Laguna, P.; Miller, W.A.; Zurek, W.H.

    1991-01-01

    The analysis of stars in galactic nuclei that are captured and tidally disrupted by a black hole of mass > 10{sup 6} M{sub {circle dot}} requires the inclusion of general relativistic effects. We present the first numerical study of tidal breakup of a 1M{sub {circle dot}} main sequence star by a 10{sup 7} M{sub {circle dot}} black hole. We use a smoothed particle code to solve the hydrodynamic equations for a relativistic fluid in a static curved spacetime geometry to analyze, among other things, the fraction of the debris captured by the hole and the velocity of fragments escaping the hole.

  3. 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.

  4. The growth efficiency of high-redshift black holes

    NASA Astrophysics Data System (ADS)

    Pacucci, Fabio; Volonteri, Marta; Ferrara, Andrea

    2015-09-01

    The observational evidence that Super-Massive Black Holes (M• ˜ 109-10 M⊙) are already in place less than 1 Gyr after the big bang poses stringent time constraints on the growth efficiency of their seeds. Among proposed possibilities, the formation of massive (˜103-6 M⊙) seeds and/or the occurrence of super-Eddington (dot{M}>dot{M}_{Edd}) accretion episodes may contribute to the solution of this problem. In this work, using a set of astrophysically motivated initial conditions, we analytically and numerically investigate the accretion flow on to high-redshift (z ˜ 10) black holes to understand the physical requirements favouring rapid and efficient growth. Our model identifies a `feeding-dominated' accretion regime and a `feedback-limited' one, the latter being characterized by intermittent (duty cycles D ≲ 0.5) and inefficient growth, with recurring outflow episodes. We find that low-mass seeds (≲103-4 M⊙) evolve in the feedback-limited regime, while more massive seeds (≳105-6 M⊙) grow very rapidly as they are found in the feeding-dominated regime. In addition to the standard accretion model with a fixed matter-energy conversion factor (ɛ = 0.1), we have also explored slim disc models, appropriate for super-Eddington accretion, where radiation is trapped in the disc and the radiative efficiency is reduced (ɛ ≲ 0.04), which may ensure a continuous growth with dot{M} ≫ dot{M}_{Edd} (up to {˜ } 300 dot{M}_{Edd} in our simulations). Under these conditions, outflows play a negligible role and a black hole can accrete 80-100 per cent of the gas mass of the host halo (˜107 M⊙) in ˜10 Myr, while in feedback-limited systems we predict that black holes can accrete only up to ˜15 per cent of the available mass.

  5. Coevolution of Supermassive Black Holes and Galaxies across cosmic times

    NASA Astrophysics Data System (ADS)

    Aversa, Rossella

    2015-10-01

    Understanding how supermassive black holes (SMBHs) and galaxies coevolve within their host dark matter (DM) halos is a fundamental issue in astrophysics. This thesis is aimed to shed light on this topic. As a first step, we employ the recent wide samples of far-infrared (FIR) selected galaxies followed-up in X-rays, and of X-ray/optically selected active galactic nuclei (AGNs) followed-up in the FIR band, along with the classic data on AGN and stellar luminosity functions at redshift z & 1.5, to probe different stages in the coevolution of SMBHs and their host galaxies. The results of this analysis indicate the following scenario: (i) the star formation in the host galaxy proceeds within a heavily dust-enshrouded medium, at an almost constant rate, over a timescale . 0.5 - 1 Gyr, and then abruptly declines due to quasar feedback; (ii) part of the interstellar medium loses angular momentum, reaches the circum-nuclear regions, at a rate proportional to the star formation, and is temporarily stored into a massive reservoir/proto-torus, wherefrom it can be promptly accreted; (iii) the black hole (BH) grows by accretion in a self-regulated regime with radiative power that can slightly exceed the Eddington limit (L/LEdd . 4), particularly at the highest redshifts; (iv) the ensuing energy feedback from massive BHs, at its maximum, exceeds the stellar one and removes the interstellar gas, thus stopping the star formation and the fueling of the reservoir; (v) afterwards, if the gas stored in the reservoir is enough, a phase of supply-limited accretion follows, whose rate exponentially declines with a timescale of ∼3 e-folding times. We also discuss how the detailed properties and the specific evolution of the reservoir can be investigated via coordinated, high-resolution observations of starforming, strongly lensed galaxies in the (sub-)mm band with ALMA, and in the X-ray band with Chandra and the next generation of X-ray instruments. According to the scenario described

  6. Coevolution of Supermassive Black Holes and Galaxies across cosmic times

    NASA Astrophysics Data System (ADS)

    Aversa, Rossella

    2015-10-01

    Understanding how supermassive black holes (SMBHs) and galaxies coevolve within their host dark matter (DM) halos is a fundamental issue in astrophysics. This thesis is aimed to shed light on this topic. As a first step, we employ the recent wide samples of far-infrared (FIR) selected galaxies followed-up in X-rays, and of X-ray/optically selected active galactic nuclei (AGNs) followed-up in the FIR band, along with the classic data on AGN and stellar luminosity functions at redshift z & 1.5, to probe different stages in the coevolution of SMBHs and their host galaxies. The results of this analysis indicate the following scenario: (i) the star formation in the host galaxy proceeds within a heavily dust-enshrouded medium, at an almost constant rate, over a timescale . 0.5 - 1 Gyr, and then abruptly declines due to quasar feedback; (ii) part of the interstellar medium loses angular momentum, reaches the circum-nuclear regions, at a rate proportional to the star formation, and is temporarily stored into a massive reservoir/proto-torus, wherefrom it can be promptly accreted; (iii) the black hole (BH) grows by accretion in a self-regulated regime with radiative power that can slightly exceed the Eddington limit (L/LEdd . 4), particularly at the highest redshifts; (iv) the ensuing energy feedback from massive BHs, at its maximum, exceeds the stellar one and removes the interstellar gas, thus stopping the star formation and the fueling of the reservoir; (v) afterwards, if the gas stored in the reservoir is enough, a phase of supply-limited accretion follows, whose rate exponentially declines with a timescale of ∼3 e-folding times. We also discuss how the detailed properties and the specific evolution of the reservoir can be investigated via coordinated, high-resolution observations of starforming, strongly lensed galaxies in the (sub-)mm band with ALMA, and in the X-ray band with Chandra and the next generation of X-ray instruments. According to the scenario described

  7. Comparison of black hole growth in galaxy mergers with gasoline and ramses

    NASA Astrophysics Data System (ADS)

    Gabor, Jared M.; Capelo, Pedro R.; Volonteri, Marta; Bournaud, Frédéric; Bellovary, Jillian; Governato, Fabio; Quinn, Thomas

    2016-07-01

    Supermassive black hole dynamics during galaxy mergers is crucial in determining the rate of black hole mergers and cosmic black hole growth. As simulations achieve higher resolution, it becomes important to assess whether the black hole dynamics is influenced by the treatment of the interstellar medium in different simulation codes. We compare simulations of black hole growth in galaxy mergers with two codes: the smoothed particle hydrodynamics code gasoline, and the adaptive mesh refinement code ramses. We seek to identify predictions of these models that are robust despite differences in hydrodynamic methods and implementations of subgrid physics. We find that the general behavior is consistent between codes. Black hole accretion is minimal while the galaxies are well-separated (and even as they fly by within 10 kpc at the first pericenter). At late stages, when the galaxies pass within a few kpc, tidal torques drive nuclear gas inflow that triggers bursts of black hole accretion accompanied by star formation. We also note quantitative discrepancies that are model dependent: our ramses simulations show less star formation and black hole growth, and a smoother gas distribution with larger clumps and filaments than our gasoline simulations. We attribute these differences primarily to the subgrid models for black hole fueling, feedback, and gas thermodynamics. The main conclusion is that differences exist quantitatively between codes, and this should be kept in mind when making comparisons with observations. However, both codes capture the same dynamical behaviors in terms of triggering black hole accretion, star formation, and black hole dynamics, which is reassuring.

  8. Gravitational-wave limits from pulsar timing constrain supermassive black hole evolution.

    PubMed

    Shannon, R M; Ravi, V; Coles, W A; Hobbs, G; Keith, M J; Manchester, R N; Wyithe, J S B; Bailes, M; Bhat, N D R; Burke-Spolaor, S; Khoo, J; Levin, Y; Osłowski, S; Sarkissian, J M; van Straten, W; Verbiest, J P W; Wang, J-B

    2013-10-18

    The formation and growth processes of supermassive black holes (SMBHs) are not well constrained. SMBH population models, however, provide specific predictions for the properties of the gravitational-wave background (GWB) from binary SMBHs in merging galaxies throughout the universe. Using observations from the Parkes Pulsar Timing Array, we constrain the fractional GWB energy density (Ω(GW)) with 95% confidence to be Ω(GW)(H0/73 kilometers per second per megaparsec)(2) < 1.3 × 10(-9) (where H0 is the Hubble constant) at a frequency of 2.8 nanohertz, which is approximately a factor of 6 more stringent than previous limits. We compare our limit to models of the SMBH population and find inconsistencies at confidence levels between 46 and 91%. For example, the standard galaxy formation model implemented in the Millennium Simulation Project is inconsistent with our limit with 50% probability. PMID:24136962

  9. THE FORMATION OF SUPERMASSIVE BLACK HOLES FROM LOW-MASS POP III SEEDS

    SciTech Connect

    Whalen, Daniel J.; Fryer, Chris L.

    2012-09-01

    The existence of 10{sup 9} M{sub Sun} black holes (BHs) in massive galaxies by z {approx} 7 is one of the great unsolved mysteries in cosmological structure formation. One theory argues that they originate from the BHs of Pop III stars at z {approx} 20 and then accrete at the Eddington limit down to the epoch of reionization, which requires that they have constant access to rich supplies of fuel. Because early numerical simulations suggested that Pop III stars were {approx}>100 M{sub Sun }, the supermassive black hole (SMBH) seeds considered up to now were 100-300 M{sub Sun }. However, there is a growing numerical and observational consensus that some Pop III stars were tens of solar masses, not hundreds, and that 20-40 M{sub Sun} BHs may have been much more plentiful at high redshift. However, we find that natal kicks imparted to 20-40 M{sub Sun} Pop III BHs during formation eject them from their halos and hence their fuel supply, precluding them from Eddington-limit growth. Consequently, SMBHs are far less likely to form from low-mass Pop III stars than from very massive ones.

  10. Simulating the growth of Intermediate Mass Black Holes

    NASA Astrophysics Data System (ADS)

    Pacucci, Fabio; Ferrara, Andrea

    2015-03-01

    Theoretical models predict that a population of intermediate-mass black holes (IMBHs) of mass M• ≈ 104-5 M⊙ might form at high (z ≳ 10) redshift by different processes. Such objects would represent the seeds out of which z ≳ 6 supermassive black holes grow. We numerically investigate the radiation-hydrodynamic evolution governing the growth of such seeds via accretion of primordial gas within their parent dark matter halo of virial temperature Tvir ˜ 104 K. We find that the accretion on to a direct collapse black hole of initial mass M0 = 105 M⊙ occurs at an average rate dot{M}_{•} ≃ 1.35 dot{M}_Edd ˜eq 0.1 M_{{⊙} yr^{-1}}, is intermittent (duty cycle ≲ 50 per cent) and lasts ≈142 Myr; the system emits on average at super-Eddington luminosities, progressively becoming more luminous as the density of the inner mass shells, directly feeding the central object, increases. Finally, when ≈90 per cent of the gas mass has been accreted (in spite of an average super-Eddington emission) on to the black hole, whose final mass is ˜7 × 106 M⊙, the remaining gas is ejected from the halo due to a powerful radiation burst releasing a peak luminosity Lpeak ˜ 3 × 1045 erg s-1. The IMBH is Compton-thick during most of the evolution, reaching a column density NH ˜ 1025 cm-2 in the late stages of the simulation. We briefly discuss the observational implications of the model.

  11. Era of Galaxy and Black Hole Growth Spurt Discovered

    NASA Astrophysics Data System (ADS)

    2005-04-01

    Distant galaxies undergoing intense bursts of star formation have been shown by NASA's Chandra X-ray Observatory to be fertile growing grounds for the largest black holes in the Universe. Collisions between galaxies in the early Universe may be the ultimate cause for both the accelerated star formation and black hole growth. By combining the deepest X-ray image ever obtained with submillimeter and optical observations, an international team of scientists has found evidence that some extremely luminous adolescent galaxies and their central black holes underwent a phenomenal spurt of growth more than 10 billion years ago. This concurrent black hole and galaxy growth spurt is only seen in these galaxies and may have set the stage for the birth of quasars - distant galaxies that contain the largest and most active black holes in the Universe. Simulation of a Galaxy Collision Simulation of a Galaxy Collision "The extreme distances of these galaxies allow us to look back in time, and take a snapshot of how today's largest galaxies looked when they were producing most of their stars and growing black holes," said David Alexander of the University of Cambridge, UK, and lead author of a paper in the April 7, 2005 issue of Nature that describes this work. The galaxies studied by Alexander and his colleagues are known as submillimeter galaxies, so-called because they were originally identified by the James Clerk Maxwell submillimeter telescope (JCMT) on Mauna Kea in Hawaii. The submillimeter observations along with optical data from Keck indicate these galaxies had an unusually large amount of gas. The gas in each galaxy was forming into stars at a rate of about one per day, or 100 times the present rate in the Milky Way galaxy. The Chandra X-ray data show that the supermassive black holes in the galaxies were also growing at the same time. Chandra X-ray Image of CDFN Chandra X-ray Image of CDFN These galaxies are very faint and it is only with the deepest observations of the

  12. Lense-Thirring precession around supermassive black holes during tidal disruption events

    NASA Astrophysics Data System (ADS)

    Franchini, Alessia; Lodato, Giuseppe; Facchini, Stefano

    2016-01-01

    A tidal disruption event occurs when a star wanders close enough to a black hole to be disrupted by its tidal force. The debris of a tidally disrupted star are expected to form an accretion disc around the supermassive black hole. The light curves of these events sometimes show a quasi-periodic modulation of the flux that can be associated with the precession of the accretion disc due to the Lense-Thirring (`frame-dragging') effect. Since the initial star orbit is in general inclined with respect to the black hole spin, this misalignment combined with the Lense-Thirring effect leads to a warp in the disc. In this paper, we provide a simple model of the system composed by a thick and narrow accretion disc surrounding a spinning supermassive black hole, with the aim to: (a) compute the expected precession period as a function of the system parameters, (b) discuss the conditions that have to be satisfied in order to have rigid precession, (c) investigate the alignment process, highlighting how different mechanisms play a role leading the disc and the black hole angular momenta into alignment.

  13. Supermassive Black Holes and Their Host Spheroids. I. Disassembling Galaxies

    NASA Astrophysics Data System (ADS)

    Savorgnan, G. A. D.; Graham, A. W.

    2016-01-01

    Several recent studies have performed galaxy decompositions to investigate correlations between the black hole mass and various properties of the host spheroid, but they have not converged on the same conclusions. This is because their models for the same galaxy were often significantly different and not consistent with each other in terms of fitted components. Using 3.6 μm Spitzer imagery, which is a superb tracer of the stellar mass (superior to the K band), we have performed state-of-the-art multicomponent decompositions for 66 galaxies with directly measured black hole masses. Our sample is the largest to date and, unlike previous studies, contains a large number (17) of spiral galaxies with low black hole masses. We paid careful attention to the image mosaicking, sky subtraction, and masking of contaminating sources. After a scrupulous inspection of the galaxy photometry (through isophotal analysis and unsharp masking) and—for the first time—2D kinematics, we were able to account for spheroids large-scale, intermediate-scale, and nuclear disks bars rings spiral arms halos extended or unresolved nuclear sources; and partially depleted cores. For each individual galaxy, we compared our best-fit model with previous studies, explained the discrepancies, and identified the optimal decomposition. Moreover, we have independently performed one-dimensional (1D) and two-dimensional (2D) decompositions and concluded that, at least when modeling large, nearby galaxies, 1D techniques have more advantages than 2D techniques. Finally, we developed a prescription to estimate the uncertainties on the 1D best-fit parameters for the 66 spheroids that takes into account systematic errors, unlike popular 2D codes that only consider statistical errors.

  14. MCMC exploration of supermassive black hole binary inspirals

    NASA Astrophysics Data System (ADS)

    Cornish, Neil J.; Porter, Edward K.

    2006-10-01

    The Laser Interferometer Space Antenna will be able to detect the inspiral and merger of super massive black hole binaries (SMBHBs) anywhere in the universe. Standard matched filtering techniques can be used to detect and characterize these systems. Markov Chain Monte Carlo (MCMC) methods are ideally suited to this and other LISA data analysis problems as they are able to efficiently handle models with large dimensions. Here we compare the posterior parameter distributions derived by an MCMC algorithm with the distributions predicted by the Fisher information matrix. We find excellent agreement for the extrinsic parameters, while the Fisher matrix slightly overestimates errors in the intrinsic parameters.

  15. A Normal Supermassive Black Hole in NGC 1277

    NASA Astrophysics Data System (ADS)

    Graham, Alister W.; Durré, Mark; Savorgnan, Giulia A. D.; Medling, Anne M.; Batcheldor, Dan; Scott, Nicholas; Watson, Beverly; Marconi, Alessandro

    2016-03-01

    The identification of galaxies with “overly massive” black holes requires two measurements: a black hole mass (Mbh) and a host spheroid mass ({M}{{sph,\\ast }}). Here we provide our measurements for NGC 1277. Our structural decomposition reveals that NGC 1277 is dominated by a “classical” spheroid with a Sérsic index n = 5.3, a half-light radius {R}{{e,major}}=2.1 {{kpc}}, and a stellar mass of 2.7× {10}11\\quad {M}⊙ (using {M}*/{L}V=11.65, Martín-Navarro et al.). This mass is an order of magnitude greater than originally reported. Using the latest Mbh-n, Mbh-{M}{{sph,\\ast }}, and Mbh-σ relations, the expected black hole mass is, respectively, ({0.57}-0.40+1.29)× {10}9\\quad {M}⊙ , ({1.58}-1.13+4.04)× {10}9\\quad {M}⊙ , and ({2.27}-1.44+4.04)× {10}9\\quad {M}⊙ (using σ = 300 km s-1) for which the “sphere-of-influence” is 0.″31. Our new kinematical maps obtained from laser guide star assisted, adaptive optics on the Keck I Telescope dramatically reaffirm the presence of the inner, nearly edge-on, disk seen in the galaxy image. We also report that this produces a large velocity shear (˜400 km s-1) across the inner 0.″2 (70 pc) plus elevated values of \\sqrt{{σ }2+{V}2} across the inner (+/- 3\\buildrel{\\prime\\prime}\\over{.} 8)× (+/- 0\\buildrel{\\prime\\prime}\\over{.} 6) region of the galaxy. Our new multi-Gaussian expansion (MGE) models and Jeans Anisotropic MGE analysis struggled to match this extended component. Our optimal black hole mass, albeit a probable upper limit because of the disk is 1.2 × 109 M⊙ (M/{L}V=12.3). This is an order of magnitude smaller than originally reported and 4 times smaller than recently reported. It gives an {M}{{bh}}/{M}{{sph,\\ast }} ratio of 0.45% in agreement with the median (≈0.5%) and range (0.1%-5.0%) observed in non-dwarf, early-type galaxies. This result highlights the need for caution with inner disks.

  16. A close-pair binary in a distant triple supermassive black hole system.

    PubMed

    Deane, R P; Paragi, Z; Jarvis, M J; Coriat, M; Bernardi, G; Fender, R P; Frey, S; Heywood, I; Klöckner, H-R; Grainge, K; Rumsey, C

    2014-07-01

    Galaxies are believed to evolve through merging, which should lead to some hosting multiple supermassive black holes. There are four known triple black hole systems, with the closest black hole pair being 2.4 kiloparsecs apart (the third component in this system is at 3 kiloparsecs), which is far from the gravitational sphere of influence (about 100 parsecs for a black hole with mass one billion times that of the Sun). Previous searches for compact black hole systems concluded that they were rare, with the tightest binary system having a separation of 7 parsecs (ref. 10). Here we report observations of a triple black hole system at redshift z = 0.39, with the closest pair separated by about 140 parsecs and significantly more distant from Earth than any other known binary of comparable orbital separation. The effect of the tight pair is to introduce a rotationally symmetric helical modulation on the structure of the large-scale radio jets, which provides a useful way to search for other tight pairs without needing extremely high resolution observations. As we found this tight pair after searching only six galaxies, we conclude that tight pairs are more common than hitherto believed, which is an important observational constraint for low-frequency gravitational wave experiments. PMID:24990745

  17. A supermassive black hole in an ultra-compact dwarf galaxy.

    PubMed

    Seth, Anil C; van den Bosch, Remco; Mieske, Steffen; Baumgardt, Holger; den Brok, Mark; Strader, Jay; Neumayer, Nadine; Chilingarian, Igor; Hilker, Michael; McDermid, Richard; Spitler, Lee; Brodie, Jean; Frank, Matthias J; Walsh, Jonelle L

    2014-09-18

    Ultra-compact dwarf galaxies are among the densest stellar systems in the Universe. These systems have masses of up to 2 × 10(8) solar masses, but half-light radii of just 3-50 parsecs. Dynamical mass estimates show that many such dwarfs are more massive than expected from their luminosity. It remains unclear whether these high dynamical mass estimates arise because of the presence of supermassive black holes or result from a non-standard stellar initial mass function that causes the average stellar mass to be higher than expected. Here we report adaptive optics kinematic data of the ultra-compact dwarf galaxy M60-UCD1 that show a central velocity dispersion peak exceeding 100 kilometres per second and modest rotation. Dynamical modelling of these data reveals the presence of a supermassive black hole with a mass of 2.1 × 10(7) solar masses. This is 15 per cent of the object's total mass. The high black hole mass and mass fraction suggest that M60-UCD1 is the stripped nucleus of a galaxy. Our analysis also shows that M60-UCD1's stellar mass is consistent with its luminosity, implying a large population of previously unrecognized supermassive black holes in other ultra-compact dwarf galaxies. PMID:25230660

  18. No Supermassive Black Holes in Giant Galaxy Disks: M101 and NGC 6946

    NASA Astrophysics Data System (ADS)

    Kormendy, John; Drory, N.; Cornell, M. E.; Bender, R.

    2007-12-01

    The Hobby-Eberly Telescope was used to obtain high-resolution spectroscopy of the nuclear star clusters in the bulgeless, giant Scd galaxies M101 and NGC 6946. Their nuclei have velocity dispersions of 25 to 40 km/s. Any supermassive black holes in these clusters must have masses less than approximately 10**4 to 10**5 solar masses. Similar results are obtained for IC 342 from a published velocity dispersion. These limits are much smaller than masses that are predicted if black holes in bulgeless galaxies correlated with galaxy disk properties such as rotation velocities V in the same way that black holes correlate with elliptical galaxy and bulge properties such as velocity dispersions. Since these are giant galaxies with V = 200 km/s, this result provides an especially stringent check that black holes do not correlate with galaxy disks. All three galaxies contain little or no pseudobulge component, either, a result that can be understood from dynamical arguments. Therefore gas inflow processes like those that occur rapidly in galaxy mergers and slowly in internally driven secular evolution are essentially unavailable for black hole feeding. However, some (pseudo)bulgeless galaxies, including IC 342 and NGC 6946, show weak Seyfert activity, and some are known to contain relatively low-mass black holes. This is a hint that low-mass black holes in bulgeless galaxies and high-mass black holes in bulges and ellipticals may have fundamentally different formation histories. This work was supported by the National Science Foundation through grant AST-0607490.

  19. 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. PMID:12817138

  20. THE FIRST SPECTROSCOPICALLY RESOLVED SUB-PARSEC ORBIT OF A SUPERMASSIVE BINARY BLACK HOLE

    SciTech Connect

    Bon, E.; Jovanovic, P.; Bon, N.; Popovic, L. C.; Marziani, P.; Shapovalova, A. I.; Borka Jovanovic, V.; Borka, D.; Sulentic, J.

    2012-11-10

    One of the most intriguing scenarios proposed to explain how active galactic nuclei are triggered involves the existence of a supermassive binary black hole (BH) system in their cores. Here, we present an observational evidence for the first spectroscopically resolved sub-parsec orbit of a such system in the core of Seyfert galaxy NGC 4151. Using a method similar to those typically used for spectroscopic binary stars, we obtained radial velocity curves of the supermassive binary system, from which we calculated orbital elements and made estimates about the masses of the components. Our analysis shows that periodic variations in the light and radial velocity curves can be accounted for by an eccentric, sub-parsec Keplerian orbit with a 15.9 year period. The flux maximum in the light curve corresponds to the approaching phase of the secondary component toward the observer. According to the obtained results, we speculate that the periodic variations in the observed H{alpha} line shape and flux are due to shock waves generated by the supersonic motion of the components through the surrounding medium. Given the large observational effort needed to reveal this spectroscopically resolved binary orbital motion, we suggest that many such systems may exist in similar objects even if they are hard to find. Detecting more of them will provide us with insight into the BH mass growth process.

  1. Prospects for measuring supermassive black hole masses with future extremely large telescopes

    SciTech Connect

    Do, Tuan; Wright, Shelley A.; Barth, Aaron J.; Barton, Elizabeth J.; Simard, Luc; Larkin, James E.; Moore, Anna M.; Wang, Lianqi; Ellerbroek, Brent

    2014-04-01

    The next generation of giant-segmented mirror telescopes (>20 m) will enable us to observe galactic nuclei at much higher angular resolution and sensitivity than ever before. These capabilities will introduce a revolutionary shift in our understanding of the origin and evolution of supermassive black holes by enabling more precise black hole mass measurements in a mass range that is unreachable today. We present simulations and predictions of the observations of nuclei that will be made with the Thirty Meter Telescope (TMT) and the adaptive optics assisted integral-field spectrograph IRIS, which is capable of diffraction-limited spectroscopy from Z band (0.9 μm) to K band (2.2 μm). These simulations, for the first time, use realistic values for the sky, telescope, adaptive optics system, and instrument to determine the expected signal-to-noise ratio of a range of possible targets spanning intermediate mass black holes of ∼10{sup 4} M {sub ☉} to the most massive black holes known today of >10{sup 10} M {sub ☉}. We find that IRIS will be able to observe Milky Way mass black holes out the distance of the Virgo Cluster, and will allow us to observe many more of the brightest cluster galaxies where the most massive black holes are thought to reside. We also evaluate how well the kinematic moments of the velocity distributions can be constrained at the different spectral resolutions and plate scales designed for IRIS. We find that a spectral resolution of ∼8000 will be necessary to measure the masses of intermediate mass black holes. By simulating the observations of galaxies found in Sloan Digital Sky Survey DR7, we find that over 10{sup 5} massive black holes will be observable at distances between 0.005 < z < 0.18 with the estimated sensitivity and angular resolution provided by access to Z-band (0.9 μm) spectroscopy from IRIS and the TMT adaptive optics system. These observations will provide the most accurate dynamical measurements of black hole masses to

  2. Gravitational wave emission from binary supermassive black holes

    NASA Astrophysics Data System (ADS)

    Sesana, A.

    2013-12-01

    Massive black hole binaries (MBHBs) are unavoidable outcomes of the hierarchical structure formation process, and, according to the theory of general relativity, are expected to be the loudest gravitational wave (GW) sources in the Universe. In this paper I provide a broad overview of MBHBs as GW sources. After reviewing the basics of GW emission from binary systems and of MBHB formation, evolution and dynamics, I describe in some details the connection between binary properties and the emitted gravitational waveform. Direct GW observations will provide an unprecedented wealth of information about the physical nature and the astrophysical properties of these extreme objects, allowing to reconstruct their cosmic history, dynamics and coupling with their dense stellar and gaseous environment. In this context I describe ongoing and future efforts to make a direct detection with space based interferometry and pulsar timing arrays, highlighting the invaluable scientific payouts of such enterprises.

  3. Flares from stars tidally disrupted by supermassive black holes

    NASA Astrophysics Data System (ADS)

    Komossa, St.

    2016-04-01

    Stellar tidal disruption events are unique probes of accretion physics and disk winds under extreme conditions. Their luminous flares of radiation are signposts of intermediate-mass black holes (BHs) and recoiling BHs. In X-rays, they have the potential to probe GR effects near the last stable orbit. Some of the events launch relativistic jets, and provide us with a powerful new method of understanding the physics of jet formation and evolution in a quiescent environment. About 30-40 candidate events have been identified by now, mostly in the X-rays and the optical. Events will be detected in the thousands in upcoming sky surveys, enabling statistical studies and rapid multi-wavelength follow-ups. Here, I provide a review of the field, including most recent results.

  4. Interim results from the ongoing hunt for supermassive black hole binaries

    NASA Astrophysics Data System (ADS)

    Runnoe, Jessie C.; Mathes, Gavin; Pennell, Alison; Brown, Stephanie Meghan; Eracleous, Michael; Boroson, Todd A.; Bogdanovic, Tamara; Sigurdsson, Steinn; Halpern, Jules P.; Liu, Jia

    2016-01-01

    Supermassive black hole binaries seem to be an inevitable product of the prevailing galaxy evolution scenarios in which most massive galaxies play host to a central black hole and undergo a history of mergers and accretion over the course of cosmic time. The early stages of this process have been observed in the form of interacting galaxy pairs as well dual active galactic nuclei with kilo-parsec separations, but detections of the close, bound binaries that are expected to follow have proven elusive. With this motivation, we have been conducting a systematic observational search for sub-parsec separation supermassive black hole binaries. Specifically, we test the hypothesis that the secondary black hole in the system is active and the resulting broad emission lines are doppler shifted due to orbital motion in the binary (analogous to a single-line spectroscopc binary star). Our sample includes 88 binary candidates selected from z<0.7 Sloan Digital Sky Survey quasars based on substantial offsets (>1000 km/s) of their broad Hβ emission lines relative to their systemic redshifts. I will present the latest results from the spectroscopic monitoring campaign that we are conducting to constrain the nature of the binary candidates. These include the radial velocity curves, which now use observations made through 2015, and the constraints that can be placed on the physical properties of the binary based on the radial velocity curves and observed flux variability of the binaries.

  5. Spin and mass of the supermassive black hole in the Galactic Center

    SciTech Connect

    Dokuchaev, V. I.

    2015-12-15

    A new method for exact determination of the masses and spins of black holes from the observations of quasi-periodic oscillations is discussed. The detected signal from the hot clumps in the accretion plasma must contain modulations with two characteristic frequencies: the frequency of rotation of the black hole event horizon and the frequency of the latitudinal precession of the clump’s orbit. Application of the method of two characteristic frequencies for interpretation of the observed quasi-periodic oscillations from the supermassive black hole in the Galactic center in the X-rays and in the near IR region yields the most exact, for the present, values of the mass and the spin (Kerr parameter) of the Sgr A* black hole: M = (4.2 ± 0.2) × 10{sup 6}M{sub ⊙} and a = 0.65 ± 0.05. The observed quasi-periodic oscillations with a period of about 11.5 min are identified as the black hole event horizon rotation period and those with a period of about 19 min are identified as the latitudinal oscillation period of the hot spot orbits in the accretion disk.

  6. Resolving the Bondi Accretion Flow toward the Supermassive Black Hole of NGC 3115 with Chandra

    NASA Astrophysics Data System (ADS)

    Wong, Ka-Wah; Irwin, J.; Million, E.; Yukita, M.; Mathews, W.; Bregman, J.

    2011-09-01

    Gas undergoing Bondi accretion on to a supermassive black hole (SMBH) becomes hotter toward smaller radii. We searched for this signature with a Chandra observation of the hot gas in NGC 3115, which optical observation show has a very massive SMBH. Our observations show that the gas temperature rises toward the galaxy center as expected in all accretion models in which the black hole is gravitationally capturing the ambient gas. The data support that the Bondi radius is at least about 4-5 arcsec (188-235 pc), suggesting a supermassive blackhole of two billion solar masses that is consistent with the upper end of the optical results. The density profile within the Bondi radius has a power law index of 1.03, and we will discuss the interpretations of the results.

  7. The shortest-known-period star orbiting our Galaxy's supermassive black hole.

    PubMed

    Meyer, L; Ghez, A M; Schödel, R; Yelda, S; Boehle, A; Lu, J R; Do, T; Morris, M R; Becklin, E E; Matthews, K

    2012-10-01

    Stars with short orbital periods at the center of our Galaxy offer a powerful probe of a supermassive black hole. Over the past 17 years, the W. M. Keck Observatory has been used to image the galactic center at the highest angular resolution possible today. By adding to this data set and advancing methodologies, we have detected S0-102, a star orbiting our Galaxy's supermassive black hole with a period of just 11.5 years. S0-102 doubles the number of known stars with full phase coverage and periods of less than 20 years. It thereby provides the opportunity, with future measurements, to resolve degeneracies in the parameters describing the central gravitational potential and to test Einstein's theory of general relativity in an unexplored regime. PMID:23042888

  8. Spin properties of supermassive black holes with powerful outflows

    NASA Astrophysics Data System (ADS)

    Daly, Ruth. A.

    2016-05-01

    Relationships between beam power and accretion disc luminosity are studied for a sample of 55 high excitation radio galaxies (HERG), 13 low excitation radio galaxies (LERG), and 29 radio loud quasars (RLQ) with powerful outflows. The ratio of beam power to disc luminosity tends to be high for LERG, low for RLQ, and spans the full range of values for HERG. Writing general expressions for the disc luminosity and beam power and applying the empirically determined relationships allows a function that parametrizes the spins of the holes to be estimated. Interestingly, one of the solutions that is consistent with the data has a functional form that is remarkably similar to that expected in the generalized Blandford-Znajek model with a magnetic field that is similar in form to that expected in magnetically arrested disk (MAD) and advection-dominated accretion flow (ADAF) models. Values of the spin function, obtained independent of specific outflow models, suggest that spin and active galactic nucleus type are not related for these types of sources. The spin function can be used to solve for black hole spin in the context of particular outflow models, and one example is provided.

  9. MASSES OF NEARBY SUPERMASSIVE BLACK HOLES WITH VERY LONG BASELINE INTERFEROMETRY

    SciTech Connect

    Johannsen, Tim; Psaltis, Dimitrios; Marrone, Daniel P.; Oezel, Feryal; Gillessen, Stefan; Doeleman, Sheperd S.; Fish, Vincent L.

    2012-10-10

    Dynamical mass measurements to date have allowed determinations of the mass M and the distance D of a number of nearby supermassive black holes. In the case of Sgr A*, these measurements are limited by a strong correlation between the mass and distance scaling roughly as M {approx} D {sup 2}. Future very long baseline interferometric (VLBI) observations will image a bright and narrow ring surrounding the shadow of a supermassive black hole, if its accretion flow is optically thin. In this paper, we explore the prospects of reducing the correlation between mass and distance with the combination of dynamical measurements and VLBI imaging of the ring of Sgr A*. We estimate the signal-to-noise ratio of near-future VLBI arrays that consist of five to six stations, and we simulate measurements of the mass and distance of Sgr A* using the expected size of the ring image and existing stellar ephemerides. We demonstrate that, in this best-case scenario, VLBI observations at 1 mm can improve the error on the mass by a factor of about two compared to the results from the monitoring of stellar orbits alone. We identify the additional sources of uncertainty that such imaging observations have to take into account. In addition, we calculate the angular diameters of the bright rings of other nearby supermassive black holes and identify the optimal targets besides Sgr A* that could be imaged by a ground-based VLBI array or future space-VLBI missions allowing for refined mass measurements.

  10. Shaping the relation between the mass of supermassive black holes and the velocity dispersion of galactic bulges

    NASA Astrophysics Data System (ADS)

    Chan, M. H.

    2013-05-01

    I use the fact that the radiation emitted by the accretion disk of supermassive black hole can heat up the surrounding gas in the protogalaxy to achieve hydrostatic equilibrium during the galaxy formation. The correlation between the black hole mass M BH and velocity dispersion σ thus naturally arises. The result generally agrees with empirical fittings from observational data, even with M BH ≤106 M ⊙. This model provides a clear picture on how the properties of the galactic supermassive black holes are connected with the kinetic properties of the galactic bulges.

  11. DISCOVERY OF AN H{alpha} EMITTING DISK AROUND THE SUPERMASSIVE BLACK HOLE OF M31

    SciTech Connect

    Menezes, R. B.; Steiner, J. E.; Ricci, T. V.

    2013-01-10

    Due to its proximity, the mass of the supermassive black hole in the nucleus of the Andromeda galaxy (M31), the most massive black hole in the Local Group of galaxies, has been measured by several methods involving the kinematics of a stellar disk which surrounds it. We report here the discovery of an eccentric H{alpha} emitting disk around the black hole at the center of M31 and show how modeling this disk can provide an independent determination of the mass of the black hole. Our model implies a mass of 5.0{sup +0.8}{sub -1.0} Multiplication-Sign 10{sup 7} M{sub Sun} for the central black hole, consistent with the average of determinations by methods involving stellar dynamics, and compatible (at 1{sigma} level) with measurements obtained from the most detailed models of the stellar disk around the central black hole. This value is also consistent with the M-{sigma} relation. In order to make a comparison, we applied our simulation on the stellar kinematics in the nucleus of M31 and concluded that the parameters obtained for the stellar disk are not formally compatible with the parameters obtained for the H{alpha} emitting disk. This result suggests that the stellar and the H{alpha} emitting disks are intrinsically different from each other. A plausible explanation is that the H{alpha} emission is associated with a gaseous disk. This hypothesis is supported by the detection of traces of weaker nebular lines in the nuclear region of M31. However, we cannot exclude the possibility that the H{alpha} emission is, at least partially, generated by stars.

  12. COSMOLOGICAL EVOLUTION OF SUPERMASSIVE BLACK HOLES. II. EVIDENCE FOR DOWNSIZING OF SPIN EVOLUTION

    SciTech Connect

    Li Yanrong; Wang Jianmin; Ho, Luis C. E-mail: wangjm@mail.ihep.ac.cn

    2012-04-20

    The spin is an important but poorly constrained parameter for describing supermassive black holes (SMBHs). Using the continuity equation of SMBH number density, we explicitly obtain the mass-dependent cosmological evolution of the radiative efficiency for accretion, which serves as a proxy for SMBH spin. Our calculations make use of the SMBH mass function of active and inactive galaxies (derived in the first paper of this series), the bolometric luminosity function of active galactic nuclei (AGNs), corrected for the contribution from Compton-thick sources, and the observed Eddington ratio distribution. We find that the radiative efficiency generally increases with increasing black hole mass at high redshifts (z {approx}> 1), roughly as {eta}{proportional_to}M{sup 0.5}{sub .}, while the trend reverses at lower redshifts, such that the highest efficiencies are attained by the lowest mass black holes. Black holes with M{sub .} {approx}> 10{sup 8.5} M{sub Sun} maintain radiative efficiencies as high as {eta} Almost-Equal-To 0.3-0.4 at high redshifts, near the maximum for rapidly spinning systems, but their efficiencies drop dramatically (by an order of magnitude) by z Almost-Equal-To 0. The pattern for lower mass holes is somewhat more complicated but qualitatively similar. Assuming that the standard accretion disk model applies, we suggest that the accretion history of SMBHs and their accompanying spins evolves in two distinct regimes: an early phase of prolonged accretion, plausibly driven by major mergers, during which the black hole spins up, then switching to a period of random, episodic accretion, governed by minor mergers and internal secular processes, during which the hole spins down. The transition epoch depends on mass, mirroring other evidence for 'cosmic downsizing' in the AGN population; it occurs at z Almost-Equal-To 2 for high-mass black holes and somewhat later, at z Almost-Equal-To 1, for lower mass systems.

  13. H I OBSERVATIONS OF THE SUPERMASSIVE BINARY BLACK HOLE SYSTEM IN 0402+379

    SciTech Connect

    Rodriguez, C.; Taylor, G. B.; Pihlstroem, Y. M.; Zavala, R. T.; Peck, A. B.

    2009-05-20

    We have recently discovered a supermassive binary black hole system with a projected separation between the two black holes of 7.3 pc in the radio galaxy 0402+379 (Rodriguez et al. 2006). This is the most compact supermassive binary black hole pair yet imaged by more than two orders of magnitude. We present Global VLBI observations at 1.3464 GHz of this radio galaxy, taken to improve the quality of the H I data. Two absorption lines are found toward the southern jet of the source, one redshifted by 370 {+-} 10 km s{sup -1} and the other blueshifted by 700 {+-} 10 km s{sup -1} with respect to the systemic velocity of the source, which, along with the results obtained for the opacity distribution over the source, suggests the presence of two mass clumps rotating around the central region of the source. We propose a model consisting of a geometrically thick disk, of which we only see a couple of clumps, that reproduces the velocities measured from the H I absorption profiles. These clumps rotate in circular Keplerian orbits around an axis that crosses one of the supermassive black holes of the binary system in 0402+379. We find an upper limit for the inclination angle of the twin jets of the source to the line of sight of {theta} = 66 deg., which, according to the proposed model, implies a lower limit on the central mass of {approx}7 x 10{sup 8} M {sub sun} and a lower limit for the scale height of the thick disk of {approx}12 pc.

  14. EXPLORING THE UNUSUALLY HIGH BLACK-HOLE-TO-BULGE MASS RATIOS IN NGC 4342 AND NGC 4291: THE ASYNCHRONOUS GROWTH OF BULGES AND BLACK HOLES

    SciTech Connect

    Bogdan, Akos; Forman, William R.; Kraft, Ralph P.; Li, Zhiyuan; Vikhlinin, Alexey; Nulsen, Paul E. J.; Jones, Christine; Zhuravleva, Irina; Churazov, Eugene; Mihos, J. Christopher; Harding, Paul; Guo, Qi; Schindler, Sabine

    2012-07-10

    We study two nearby early-type galaxies, NGC 4342 and NGC 4291, that host unusually massive black holes relative to their low stellar mass. The observed black-hole-to-bulge mass ratios of NGC 4342 and NGC 4291 are 6.9{sup +3.8}{sub -2.3}% and 1.9% {+-} 0.6%, respectively, which significantly exceed the typical observed ratio of {approx}0.2%. As a consequence of the exceedingly large black-hole-to-bulge mass ratios, NGC 4342 and NGC 4291 are Almost-Equal-To 5.1{sigma} and Almost-Equal-To 3.4{sigma} outliers from the M{sub .}-M{sub bulge} scaling relation, respectively. In this paper, we explore the origin of the unusually high black-hole-to-bulge mass ratio. Based on Chandra X-ray observations of the hot gas content of NGC 4342 and NGC 4291, we compute gravitating mass profiles, and conclude that both galaxies reside in massive dark matter halos, which extend well beyond the stellar light. The presence of dark matter halos around NGC 4342 and NGC 4291 and a deep optical image of the environment of NGC 4342 indicate that tidal stripping, in which {approx}> 90% of the stellar mass was lost, cannot explain the observed high black-hole-to-bulge mass ratios. Therefore, we conclude that these galaxies formed with low stellar masses, implying that the bulge and black hole did not grow in tandem. We also find that the black hole mass correlates well with the properties of the dark matter halo, suggesting that dark matter halos may play a major role in regulating the growth of the supermassive black holes.

  15. Off The Beaten Path: Modeling the Dynamics of Supermassive Black Holes in Cosmological Simulations

    NASA Astrophysics Data System (ADS)

    Tremmel, Michael J.; Governato, Fabio; Volonteri, Marta; Quinn, Thomas R.

    2015-01-01

    Cosmological simulations are an essential tool to understand the co-evolution of supermassive black holes (SMBHs) and their host galaxies. However, the limited resolution of these simulations presents unique challenges to successfully modeling black hole dynamics. We present a novel, physically motivated method for improving the dynamics of black holes in cosmological simulations, by accounting for the unresolved dynamical friction that SMBHs feel from stars and dark matter. We show how this approach, which naturally scales with resolution, is a major step forward compared to more commonly used 'advection' models that often assume SMBHs sink very rapidly toward the center of their host galaxies. Here, we demonstrate that our method is able to prevent numerical heating of SMBHs while allowing for realistic dynamics.Our implementation will allow us to more realistically model SMBH dynamics, accretion, and mergers in cosmological simulations, giving us the ability to better understand how SMBHs grow with their host galaxies. This also provides an opportunity for more detailed studies of SMBHs in dwarf galaxies, which can give crucial insight into constraining black hole seed formation models.

  16. A strong magnetic field around the supermassive black hole at the centre of the Galaxy.

    PubMed

    Eatough, R P; Falcke, H; Karuppusamy, R; Lee, K J; Champion, D J; Keane, E F; Desvignes, G; Schnitzeler, D H F M; Spitler, L G; Kramer, M; Klein, B; Bassa, C; Bower, G C; Brunthaler, A; Cognard, I; Deller, A T; Demorest, P B; Freire, P C C; Kraus, A; Lyne, A G; Noutsos, A; Stappers, B; Wex, N

    2013-09-19

    Earth's nearest candidate supermassive black hole lies at the centre of the Milky Way. Its electromagnetic emission is thought to be powered by radiatively inefficient accretion of gas from its environment, which is a standard mode of energy supply for most galactic nuclei. X-ray measurements have already resolved a tenuous hot gas component from which the black hole can be fed. The magnetization of the gas, however, which is a crucial parameter determining the structure of the accretion flow, remains unknown. Strong magnetic fields can influence the dynamics of accretion, remove angular momentum from the infalling gas, expel matter through relativistic jets and lead to synchrotron emission such as that previously observed. Here we report multi-frequency radio measurements of a newly discovered pulsar close to the Galactic Centre and show that the pulsar's unusually large Faraday rotation (the rotation of the plane of polarization of the emission in the presence of an external magnetic field) indicates that there is a dynamically important magnetic field near the black hole. If this field is accreted down to the event horizon it provides enough magnetic flux to explain the observed emission--from radio to X-ray wavelengths--from the black hole. PMID:23945588

  17. Astronomical constraints on quantum theories of cold dark matter - II. Supermassive black holes and luminous matter

    NASA Astrophysics Data System (ADS)

    Spivey, S. C.; Musielak, Z. E.; Fry, J. L.

    2015-04-01

    Our previous model of quantum cold dark matter (QCDM) is expanded to include the influence of supermassive black holes located at centres of different galaxies and galactic luminous (baryonic) matter distributions. The inclusion of a black hole to the galactic potential is shown to produce a more concentrated halo with a cuspier core. The addition of a small-scale galactic luminous matter distribution also concentrates the halo, while a large-scale distribution diffuses it; nevertheless, in either case the smooth core of the halo is preserved. Effects caused by including a non-linear scattering term are investigated by solving the Gross-Pitaevskii equation. The obtained results demonstrate that the scattering term produces a rounder and more diffuse density profile. Moreover, adding a sufficiently large black hole in combination with this term results in an even cuspier profile than the black hole alone. As a result of all these additions, our extended QCDM model can be applied to a much larger range of dark matter halo shapes and sizes.

  18. Compact object mergers: observations of supermassive binary black holes and stellar tidal disruption events

    NASA Astrophysics Data System (ADS)

    Komossa, S.; Zensus, J. A.

    2016-02-01

    The capture and disruption of stars by supermassive black holes (SMBHs), and the formation and coalescence of binaries, are inevitable consequences of the presence of SMBHs at the cores of galaxies. Pairs of active galactic nuclei (AGN) and binary SMBHs are important stages in the evolution of galaxy mergers, and an intense search for these systems is currently ongoing. In the early and advanced stages of galaxy merging, observations of the triggering of accretion onto one or both BHs inform us about feedback processes and BH growth. Identification of the compact binary SMBHs at parsec and sub-parsec scales provides us with important constraints on the interaction processes that govern the shrinkage of the binary beyond the ``final parsec''. Coalescing binary SMBHs are among the most powerful sources of gravitational waves (GWs) in the universe. Stellar tidal disruption events (TDEs) appear as luminous, transient, accretion flares when part of the stellar material is accreted by the SMBH. About 30 events have been identified by multi-wavelength observations by now, and they will be detected in the thousands in future ground-based or space-based transient surveys. The study of TDEs provides us with a variety of new astrophysical tools and applications, related to fundamental physics or astrophysics. Here, we provide a review of the current status of observations of SMBH pairs and binaries, and TDEs, and discuss astrophysical implications.

  19. Sensitive Spitzer Photometry of Supermassive Black Holes at the Final Stage of Adolescence

    NASA Astrophysics Data System (ADS)

    Shemmer, Ohad; Netzer, Hagai; Mor, Rivay; Trakhtenbrot, Benny

    2011-05-01

    We propose to obtain sensitive Spitzer snapshot observations of a unique sample of 35 Sloan Digital Sky Survey quasars at redshift 4.8 for which we obtained reliable, Mg II-based determinations of the supermassive black hole (SMBH) mass and normalized accretion rate (L/L_Edd). These quasars appear to mark the final stage of SMBH `adolescence' in the history of the Universe as their SMBHs are significantly less massive and their L/L_Edd values are significantly higher with respect to their counterparts at lower redshifts. Our observations will provide both 1) deep coverage of the fields around these quasars which will be utilized as crucial priors for our approved Herschel/SPIRE observations of these sources, and 2) coverage of the rest-frame optical SEDs of these fast accreting quasars. The results will maximize our ability to measure the star-formation rate in the host galaxies of these quasars using Herschel. We will thus be able to investigate correlations between SMBH growth and star-forming activity in the early Universe. The Spitzer photometry will also provide invaluable information about the shape of the rest-frame optical continuum in these quasars which will be used to search for extreme disk properties that may be signatures of the remarkably high accretion rates in these sources.

  20. Do Nuclear Star Clusters and Supermassive Black Holes Follow the Same Host-Galaxy Correlations?

    DOE PAGESBeta

    Erwin, Peter; Gadotti, Dimitri Alexei

    2012-01-01

    Smore » tudies have suggested that there is a strong correlation between the masses of nuclear star clusters (NSCs) and their host galaxies, a correlation which is said to be an extension of the well-known correlations between supermassive black holes (SMBHs) and their host galaxies. But careful analysis of disk galaxies—including 2D bulge/disk/bar decompositions—shows that whileMBHs correlate with the stellar mass of the bulge component of galaxies, the masses of NSCs correlate much better with the total galaxy stellar mass. In addition, the mass ratio M NSC / M ⋆ ,  tot for NSCs in spirals (at least those with Hubble typesc and later) is typically an order of magnitude smaller than the mass ratio M BH / M ⋆ ,  bul ofMBHs. The absence of a universal “central massive object” correlation argues against common formation and growth mechanisms for bothMBHs and NSCs. We also discuss evidence for a break in the NSC-host galaxy correlation, galaxies with Hubble types earlier thanbc appear to host systematically more massive NSCs than do typesc and later.« less

  1. Formation of dark matter tori around supermassive black holes via the eccentric Kozai-Lidov mechanism

    SciTech Connect

    Naoz, Smadar; Silk, Joseph

    2014-11-10

    We explore the effects of long-term secular perturbations on the distribution of dark matter particles around supermassive black hole (BH) binaries. We show that in the hierarchical (in separation) three-body problem, one of the BHs and a dark matter particle form an inner binary. Gravitational perturbations from the BH companion, on a much wider orbit, can cause the dark matter particle to reach extremely high eccentricities and even get accreted onto the BH by what is known as the eccentric Kozai-Lidov (EKL) mechanism. We show that this may produce a torus-like configuration for the dark matter distribution around the less massive member of the BH binary. We first consider an intermediate BH (IMBH) in the vicinity of our galactic center, which may be a relic of a past minor merger. We show that if the IMBH is close enough (i.e., near the stellar disk) the EKL mechanism is very efficient in exciting the eccentricity of dark matter particles in near-polar configurations to extremely high values where they are accreted by the IMBH. We show that this mechanism is even more effective if the central BH grows in mass, where we have assumed adiabatic growth. Because near-polar configurations are disrupted, a torus-like shape is formed. We also show that this behavior is also likely to be relevant for supermassive BH binaries. We suggest that if the BHs are spinning, the accreted dark matter particles may linger in the ergosphere, and thereby generate self-annihilations and produce an indirect signature of potential interest.

  2. 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. PMID:23250434

  3. SUPERMASSIVE BLACK HOLES IN THE HIERARCHICAL UNIVERSE: A GENERAL FRAMEWORK AND OBSERVATIONAL TESTS

    SciTech Connect

    Shen Yue

    2009-10-10

    We present a simple framework for the growth and evolution of supermassive black holes (SMBHs) in the hierarchical structure formation paradigm, adopting the general idea that quasar activity is triggered in major mergers. In our model, black hole accretion is triggered during major mergers (mass ratio approx>0.3) of host dark matter halos. The successive evolution of quasar luminosities follows a universal light-curve (LC) form during which the growth of the SMBH is modeled self-consistently: an initial exponential growth at a constant Eddington ratio of order unity until it reaches the peak luminosity, followed by a power-law decay. Assuming that the peak luminosity correlates with the post-merger halo mass, we convolve the LC with the triggering rate of quasar activity to predict the quasar luminosity function (LF). Our model reproduces the observed LF at 0.5 < z < 4.5 for the full luminosity ranges probed by current optical and X-ray surveys. At z < 0.5, our model underestimates the LF at L {sub bol} < 10{sup 45} erg s{sup -1}, allowing room for the active galactic nuclei (AGNs) activity triggered by secular processes instead of major mergers. At z > 4.5, in order to reproduce the observed quasar abundance, the typical quasar hosts must shift to lower mass halos, and/or minor mergers can also trigger quasar activity. Our model reproduces both the observed redshift evolution and luminosity dependence of the linear bias of quasar/AGN clustering. Due to the scatter between instantaneous luminosity and halo mass, quasar/AGN clustering weakly depends on luminosity at low-to-intermediate luminosities; but the linear bias rises rapidly with luminosity at the high luminosity end and at high redshift. In our model, the Eddington ratio distribution is roughly lognormal, which broadens and shifts to lower mean values from high luminosity quasars (L {sub bol} approx> 10{sup 46} erg s{sup -1}) to low-luminosity AGNs (L {sub bol} approx< 10{sup 45} erg s{sup -1}), in good

  4. Cosmological evolution of supermassive black holes in galactic centers unveiled by hard X-ray observations

    PubMed Central

    UEDA, Yoshihiro

    2015-01-01

    We review the current understanding of the cosmological evolution of supermassive black holes in galactic centers elucidated by X-ray surveys of active galactic nuclei (AGNs). Hard X-ray observations at energies above 2 keV are the most efficient and complete tools to find “obscured” AGNs, which are dominant populations among all AGNs. Combinations of surveys with various flux limits and survey area have enabled us to determine the space number density and obscuration properties of AGNs as a function of luminosity and redshift. The results have essentially solved the origin of the X-ray background in the energy band below ∼10 keV. The downsizing (or anti-hierarchical) evolution that more luminous AGNs have the space-density peak at higher redshifts has been discovered, challenging theories of galaxy and black hole formation. Finally, we summarize unresolved issues on AGN evolution and prospects for future X-ray missions. PMID:25971656

  5. Rapid formation of supermassive black hole binaries in galaxy mergers with gas.

    PubMed

    Mayer, L; Kazantzidis, S; Madau, P; Colpi, M; Quinn, T; Wadsley, J

    2007-06-29

    Supermassive black holes (SMBHs) are a ubiquitous component of the nuclei of galaxies. It is normally assumed that after the merger of two massive galaxies, a SMBH binary will form, shrink because of stellar or gas dynamical processes, and ultimately coalesce by emitting a burst of gravitational waves. However, so far it has not been possible to show how two SMBHs bind during a galaxy merger with gas because of the difficulty of modeling a wide range of spatial scales. Here we report hydrodynamical simulations that track the formation of a SMBH binary down to scales of a few light years after the collision between two spiral galaxies. A massive, turbulent, nuclear gaseous disk arises as a result of the galaxy merger. The black holes form an eccentric binary in the disk in less than 1 million years as a result of the gravitational drag from the gas rather than from the stars. PMID:17556550

  6. Rapid Formation of Supermassive Black Hole Binaries in Galaxy Mergers with Gas

    SciTech Connect

    Mayer, L.; Kazantzidis, S.; Madau, P.; Colpi, M.; Quinn, T.; Wadsley, J.; /McMaster U.

    2008-03-24

    Supermassive black holes (SMBHs) are a ubiquitous component of the nuclei of galaxies. It is normally assumed that, following the merger of two massive galaxies, a SMBH binary will form, shrink due to stellar or gas dynamical processes and ultimately coalesce by emitting a burst of gravitational waves. However, so far it has not been possible to show how two SMBHs bind during a galaxy merger with gas due to the difficulty of modeling a wide range of spatial scales. Here we report hydrodynamical simulations that track the formation of a SMBH binary down to scales of a few light years following the collision between two spiral galaxies. A massive, turbulent nuclear gaseous disk arises as a result of the galaxy merger. The black holes form an eccentric binary in the disk in less than a million years as a result of the gravitational drag from the gas rather than from the stars.

  7. Cosmological evolution of supermassive black holes in galactic centers unveiled by hard X-ray observations.

    PubMed

    Ueda, Yoshihiro

    2015-01-01

    We review the current understanding of the cosmological evolution of supermassive black holes in galactic centers elucidated by X-ray surveys of active galactic nuclei (AGNs). Hard X-ray observations at energies above 2 keV are the most efficient and complete tools to find "obscured" AGNs, which are dominant populations among all AGNs. Combinations of surveys with various flux limits and survey area have enabled us to determine the space number density and obscuration properties of AGNs as a function of luminosity and redshift. The results have essentially solved the origin of the X-ray background in the energy band below ∼10 keV. The downsizing (or anti-hierarchical) evolution that more luminous AGNs have the space-density peak at higher redshifts has been discovered, challenging theories of galaxy and black hole formation. Finally, we summarize unresolved issues on AGN evolution and prospects for future X-ray missions. PMID:25971656

  8. SONGLINES FROM DIRECT COLLAPSE SEED BLACK HOLES: EFFECTS OF X-RAYS ON BLACK HOLE GROWTH AND STELLAR POPULATIONS

    SciTech Connect

    Aykutalp, Aycin; Wise, John H.; Spaans, Marco; Meijerink, Rowin

    2014-12-20

    In the last decade, the growth of supermassive black holes (SMBHs) has been intricately linked to galaxy formation and evolution and is a key ingredient in the assembly of galaxies. To investigate the origin of SMBHs, we perform cosmological simulations that target the direct collapse black hole seed formation scenario in the presence of two different strong Lyman-Werner (LW) background fields. These simulations include the X-ray irradiation from a central massive black hole (MBH), H{sub 2} self-shielding, and stellar feedback from metal-free and metal-enriched stars. We find in both simulations that local X-ray feedback induces metal-free star formation ∼0.5 Myr after the MBH forms. The MBH accretion rate reaches a maximum of 10{sup –3} M {sub ☉} yr{sup –1} in both simulations. However, the duty cycle differs and is derived to be 6% and 50% for the high and low LW cases, respectively. The MBH in the high LW case grows only ∼6% in 100 Myr compared to 16% in the low LW case. We find that the maximum accretion rate is determined by the local gas thermodynamics, whereas the duty cycle is determined by the large-scale gas dynamics and gas reservoir. We conclude that radiative feedback from the central MBH plays an important role in star formation in the nuclear regions and stifling initial MBH growth relative to the typical Eddington rate argument, and that initial MBH growth might be affected by the local LW radiation field.

  9. THE SUPERMASSIVE BLACK HOLE MASS-SPHEROID STELLAR MASS RELATION FOR SERSIC AND CORE-SERSIC GALAXIES

    SciTech Connect

    Scott, Nicholas; Graham, Alister W; Schombert, James

    2013-05-01

    We have examined the relationship between supermassive black hole mass (M{sub BH}) and the stellar mass of the host spheroid (M{sub sph,*}) for a sample of 75 nearby galaxies. To derive the spheroid stellar masses we used improved Two Micron All Sky Survey K{sub s}-band photometry from the ARCHANGEL photometry pipeline. Dividing our sample into core-Sersic and Sersic galaxies, we find that they are described by very different M{sub BH}-M{sub sph,*} relations. For core-Sersic galaxies-which are typically massive and luminous, with M{sub BH} {approx}> 2 Multiplication-Sign 10{sup 8} M{sub Sun }-we find M{sub BH}{proportional_to} M{sub sph,*}{sup 0.97{+-}0.14}, consistent with other literature relations. However, for the Sersic galaxies-with typically lower masses, M{sub sph,*} {approx}< 3 Multiplication-Sign 10{sup 10} M{sub Sun }-we find M{sub BH}{proportional_to}M{sub sph,*}{sup 2.22{+-}0.58}, a dramatically steeper slope that differs by more than 2 standard deviations. This relation confirms that, for Sersic galaxies, M{sub BH} is not a constant fraction of M{sub sph,*}. Sersic galaxies can grow via the accretion of gas which fuels both star formation and the central black hole, as well as through merging. Their black hole grows significantly more rapidly than their host spheroid, prior to growth by dry merging events that produce core-Sersic galaxies, where the black hole and spheroid grow in lockstep. We have additionally compared our Sersic M{sub BH}-M{sub sph,*} relation with the corresponding relation for nuclear star clusters, confirming that the two classes of central massive object follow significantly different scaling relations.

  10. Using Pulsar Timing observations to understand the formation and evolution of supermassive black hole binaries

    NASA Astrophysics Data System (ADS)

    Cornish, Neil; Sampson, Laura; McWilliams, Sean

    2015-04-01

    The astrophysical processes that form and harden supermassive black hole binaries impart distinct features that may be observed in the gravitational-wave spectrum within the sensitive frequency range of Pulsar Timing Arrays (PTA). We investigate how well the various formation and hardening mechanisms can be constrained by applying Bayesian inference to simulated PTA data sets. We find that even without strong priors on the merger rate, any detection of the signal will place interesting constraints on the astrophysical models. Folding in priors on the merger rate allows us to place interesting constraints on the astrophysical models even before a detection is made.

  11. Seeking for the Leading Actor on the Cosmic Stage: Galaxies versus Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Bongiorno, Angela; Shankar, Francesco; Civano, Francesca; Gavignaud, Isabelle; Georgakakis, Antonis

    We present a Special Issue on the interplay of galaxies and Supermassive Black Holes (SMBHs) recently published in Advances in Astronomy. This is the introductory paper containing the motivation for this Special Issue together with a brief description of the articles which are part of the manuscript and the link to the entire book (http://www.hindawi.com/journals/aa/si/610485/). We hope this Special Issue will be useful for many astronomers who want to get an update on the current status of the AGN-Galaxy coevolution topic.

  12. DISK ASSEMBLY AND THE M {sub BH}-{sigma} {sub e} RELATION OF SUPERMASSIVE BLACK HOLES

    SciTech Connect

    Debattista, Victor P.; Kazantzidis, Stelios; Van den Bosch, Frank C. E-mail: stelios@mps.ohio-state.edu

    2013-03-01

    Recent Hubble Space Telescope observations have revealed that a majority of active galactic nuclei (AGNs) at z {approx} 1-3 are resident in isolated disk galaxies, contrary to the usual expectation that AGNs are triggered by mergers. Here we develop a new test of the cosmic evolution of supermassive black holes (SMBHs) in disk galaxies by considering the local population of SMBHs. We show that substantial SMBH growth in spiral galaxies is required as disks assemble. SMBHs exhibit a tight relation between their mass and the velocity dispersion of the spheroid within which they reside, the M {sub .}-{sigma} {sub e} relation. In disk galaxies the bulge is the spheroid of interest. We explore the evolution of the M {sub .}-{sigma} {sub e} relation when bulges form together with SMBHs on the M {sub .}-{sigma} {sub e} relation and then slowly re-form a disk around them. The formation of the disk compresses the bulge, raising its {sigma} {sub e}. We present evidence for such compression in the form of larger velocity dispersion of classical bulges compared with elliptical galaxies at the same mass. This compression leads to an offset in the M {sub .}-{sigma} {sub e} relation if it is not accompanied by an increased M {sub .}. We quantify the expected offset based on photometric data and show that, on average, SMBHs must grow by {approx}50%-65% just to remain on the M {sub .}-{sigma} {sub e} relation. We find no significant offset in the M {sub .}-{sigma} {sub e} relations of classical bulges and of ellipticals, implying that SMBHs have been growing along with disks. Our simulations demonstrate that SMBH growth is necessary for the local population of disk galaxies to have remained on the M {sub .}-{sigma} {sub e} relation.

  13. Further evidence for a supermassive black hole mass-pitch angle relation

    SciTech Connect

    Berrier, Joel C.; Kennefick, Daniel; Kennefick, Julia D.; Hartley, Matthew; Lacy, Claud H. S.; Davis, Benjamin L.; Barrows, Robert Scott; Shields, Doug; Seigar, Marc S.; Bentz, Misty C.

    2013-06-01

    We present new and stronger evidence for a previously reported relationship between galactic spiral arm pitch angle P (a measure of the tightness of spiral structure) and the mass M {sub BH} of a disk galaxy's nuclear supermassive black hole (SMBH). We use an improved method to accurately measure the spiral arm pitch angle in disk galaxies to generate quantitative data on this morphological feature for 34 galaxies with directly measured black hole masses. We find a relation of log (M/M {sub ☉}) = (8.21 ± 0.16) – (0.062 ± 0.009)P. This method is compared with other means of estimating black hole mass to determine its effectiveness and usefulness relative to other existing relations. We argue that such a relationship is predicted by leading theories of spiral structure in disk galaxies, including the density wave theory. We propose this relationship as a tool for estimating SMBH masses in disk galaxies. This tool is potentially superior when compared to other methods for this class of galaxy and has the advantage of being unambiguously measurable from imaging data alone.

  14. 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. PMID:25883352

  15. ON THE HYDRODYNAMIC INTERPLAY BETWEEN A YOUNG NUCLEAR STARBURST AND A CENTRAL SUPERMASSIVE BLACK HOLE

    SciTech Connect

    Hueyotl-Zahuantitla, Filiberto; Tenorio-Tagle, Guillermo; Silich, Sergiy; Wuensch, Richard; Palous, Jan

    2010-06-10

    We present one-dimensional numerical simulations, which consider the effects of radiative cooling and gravity on the hydrodynamics of the matter reinserted by stellar winds and supernovae within young nuclear starbursts (NSBs) with a central supermassive black hole (SMBH). The simulations confirm our previous semi-analytic results for low-energetic starbursts, evolving in a quasi-adiabatic regime, and extend them to more powerful starbursts evolving in the catastrophic cooling regime. The simulations show a bimodal hydrodynamic solution in all cases. They present a quasi-stationary accretion flow onto the black hole, defined by the matter reinserted by massive stars within the stagnation volume and a stationary starburst wind, driven by the high thermal pressure acquired in the region between the stagnation and the starburst radii. In the catastrophic cooling regime, the stagnation radius rapidly approaches the surface of the starburst region, as one considers more massive starbursts. This leads to larger accretion rates onto the SMBH and concurrently to powerful winds able to inhibit interstellar matter from approaching the NSB. Our self-consistent model thus establishes a direct physical link between the SMBH accretion rate and the nuclear star formation activity of the host galaxy and provides a good upper limit to the accretion rate onto the central black hole.

  16. A gas cloud on its way towards the supermassive black hole at the Galactic Centre.

    PubMed

    Gillessen, S; Genzel, R; Fritz, T K; Quataert, E; Alig, C; Burkert, A; Cuadra, J; Eisenhauer, F; Pfuhl, O; Dodds-Eden, K; Gammie, C F; Ott, T

    2012-01-01

    Measurements of stellar orbits provide compelling evidence that the compact radio source Sagittarius A* at the Galactic Centre is a black hole four million times the mass of the Sun. With the exception of modest X-ray and infrared flares, Sgr A* is surprisingly faint, suggesting that the accretion rate and radiation efficiency near the event horizon are currently very low. Here we report the presence of a dense gas cloud approximately three times the mass of Earth that is falling into the accretion zone of Sgr A*. Our observations tightly constrain the cloud's orbit to be highly eccentric, with an innermost radius of approach of only ∼3,100 times the event horizon that will be reached in 2013. Over the past three years the cloud has begun to disrupt, probably mainly through tidal shearing arising from the black hole's gravitational force. The cloud's dynamic evolution and radiation in the next few years will probe the properties of the accretion flow and the feeding processes of the supermassive black hole. The kilo-electronvolt X-ray emission of Sgr A* may brighten significantly when the cloud reaches pericentre. There may also be a giant radiation flare several years from now if the cloud breaks up and its fragments feed gas into the central accretion zone. PMID:22170607

  17. Gravitational radiation from a spinning compact object around a supermassive Kerr black hole in circular orbit

    SciTech Connect

    Han Wenbiao

    2010-10-15

    The gravitational waves and energy radiation from a spinning compact object with stellar mass in a circular orbit in the equatorial plane of a supermassive Kerr black hole are investigated in this paper. The effect of how the spin acts on energy and angular moment fluxes is discussed in detail. The calculation results indicate that the spin of a small body should be considered in waveform-template production for the upcoming gravitational wave detections. It is clear that when the direction of spin axes is the same as the orbitally angular momentum ('positive' spin), spin can decrease the energy fluxes which radiate to infinity. For antidirection spin ('negative'), the energy fluxes to infinity can be enlarged. And the relations between fluxes (both infinity and horizon) and spin look like quadratic functions. From frequency shift due to spin, we estimate the wave-phase accumulation during the inspiraling process of the particle. We find that the time of particle inspiral into the black hole is longer for positive spin and shorter for negative compared with the nonspinning particle. Especially, for extreme spin value, the energy radiation near the horizon of the extreme Kerr black hole is much more than that for the nonspinning one. And consequently, the maximum binging energy of the extreme spinning particle is much larger than that of the nonspinning particle.

  18. Gas squeezing during the merger of a supermassive black hole binary

    NASA Astrophysics Data System (ADS)

    Cerioli, Alice; Lodato, Giuseppe; Price, Daniel J.

    2016-03-01

    We study accretion rates during the gravitational wave-driven merger of a binary supermassive black hole embedded in an accretion disc, formed by gas driven to the centre of the galaxy. We use 3D simulations performed with PHANTOM, a smoothed particle hydrodynamics code. Contrary to previous investigations, we show that there is evidence of a `squeezing phenomenon', caused by the compression of the inner disc gas when the secondary black hole spirals towards the primary. This causes an increase in the accretion rates that always exceed the Eddington rate. We have studied the main features of the phenomenon for a mass ratio q = 10-3 between the black holes, including the effects of numerical resolution, the secondary accretion radius and the disc thickness. With our disc model with a low aspect ratio, we show that the mass expelled from the orbit of the secondary is negligible (<5 per cent of the initial disc mass), different to the findings of previous 2D simulations with thicker discs. The increase in the accretion rates in the last stages of the merger leads to an increase in luminosity, making it possible to detect an electromagnetic precursor of the gravitational wave signal emitted by the coalescence.

  19. Implications of Profile Variability in Searches for Supermassive Black Hole Binaries

    NASA Astrophysics Data System (ADS)

    Pennell, Alison; Runnoe, Jessie C.; Brown, Stephanie Meghan; Eracleous, Michael; Bogdanovic, Tamara; Boroson, Todd A.; Halpern, Jules P.

    2016-01-01

    Modern galaxy evolution scenarios suggest that supermassive black hole binaries (SBHBs) are an inevitable result of merging galaxies that host black holes in their centers. Though candidates of wide-separation dual active galactic nuclei have been detected, there is no reliable evidence for the expected close, bound binaries at separations of one parsec or less. We are searching for close SBHBs among z<0.7 SDSS quasars with offset broad emission lines. Specifically, we test the idea that, if one of the black holes is active, the orbital motion within the binary will cause its broad emission lines to exhibit periodic radial velocity shifts. Among the most significant caveats to this approach is that the variability of the broad Hβ profile may mimic radial velocity changes. Cases where the flux increases in one side of the line profile and decreases in the other are of particular concern. In order to test the extent of this problem, we introduce simulated profile variability into the observed spectra of the binary candidates and then make radial velocity measurements on the Hβ lines. We will present the results of this simulation to assess how often we will measure false radial velocity shifts as a result of changes in the shape of the broad Hβ profile.

  20. Supermassive black hole formation by the cold accretion shocks in the first galaxies

    NASA Astrophysics Data System (ADS)

    Inayoshi, K.; Omukai, K.

    2012-09-01

    We propose a new scenario for supermassive star (SMS; >~105Msolar) formation in shocked regions of colliding cold accretion flows near the centers of first galaxies. When the post-shock density is high enough for collisionally exciting H2 rovibrational levels (>~104cm-3), enhanced H2 collisional dissociation suppresses the gas to cool below 8000 K. In this case, the layer fragments into massive clouds (>~105Msolar), which collapse isothermally (~ 8000 K) by the Lyα cooling without subsequent fragmentation. As an outcome, SMSs are expected to form and evolve eventually to seeds of supermassive black holes. By calculating thermal evolution of the shocked gas, we delimit the range of post-shock conditions for the SMS formation. We also find that metal enrichment does not affect the SMS forming condition for <~10-3Zsolar if metals are in the gas phase.

  1. Unbound Debris Streams and Remnants Resulting from the Tidal Disruptions of Stars by Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Guillochon, James; McCourt, Michael; Chen, Xian; Johnson, Michael D.; Berger, Edo

    2016-05-01

    The kinetic energy of a star in orbit about a supermassive black hole is a significant fraction of its rest mass energy when its periapse is comparable to its tidal radius. Upon its destruction, a fraction of this energy is extracted and injected into the stellar debris, half of which becomes unbound from the black hole, with the fastest material moving at ∼ 0.03c. In this paper, we present a formalism for determining the fate of these unbound debris streams (UDSs) as they depart from the black hole and interact with the surrounding gas. As the density and velocity varies along the length of a UDS, we find that hydrodynamical drag quickly shapes UDSs into loop-like structures, with the densest portions of the streams leading portions of lower density. As UDSs travel outwards, their drag against the ISM increases quadratically with distance, which causes UDSs to deposit their momentum and energy into the ambient medium before the surrounding shocked ISM has a chance to cool. This sudden injection of ∼ {10}50 erg into the ambient medium generates a Sedov-like unbound debris remnant (UDR) that mimics supernova remnants (SNRs) in energetics and appearance, accelerates particles which will produce cosmic rays and synchrotron emission, and provides momentum feedback into the molecular clouds surrounding a black hole. We estimate that a few of these UDRs might be present within a couple degrees of the Galactic Center masquerading as SNRs, and that the UDR scenario is a plausible explanation for Sgr A east.

  2. THE TIDAL DISRUPTION OF GIANT STARS AND THEIR CONTRIBUTION TO THE FLARING SUPERMASSIVE BLACK HOLE POPULATION

    SciTech Connect

    MacLeod, Morgan; Guillochon, James; Ramirez-Ruiz, Enrico E-mail: jfg@ucolick.org

    2012-10-01

    Sun-like stars are thought to be regularly disrupted by supermassive black holes (SMBHs) within galactic nuclei. Yet, as stars evolve off the main sequence their vulnerability to tidal disruption increases drastically as they develop a bifurcated structure consisting of a dense core and a tenuous envelope. Here we present the first hydrodynamic simulations of the tidal disruption of giant stars and show that the core has a substantial influence on the star's ability to survive the encounter. Stars with more massive cores retain large fractions of their envelope mass, even in deep encounters. Accretion flares resulting from the disruption of giant stars should last for tens to hundreds of years. Their characteristic signature in transient searches would not be the t {sup -5/3} decay typically associated with tidal disruption events, but a correlated rise over many orders of magnitude in brightness on timescales of months to years. We calculate the relative disruption rates of stars of varying evolutionary stages in typical galactic centers, then use our results to produce Monte Carlo realizations of the expected flaring event populations. We find that the demographics of tidal disruption flares are strongly dependent on both stellar and black hole mass, especially near the limiting SMBH mass scale of {approx}10{sup 8} M{sub Sun }. At this black hole mass, we predict a sharp transition in the SMBH flaring diet beyond which all observable disruptions arise from evolved stars, accompanied by a dramatic cutoff in the overall tidal disruption flaring rate. Black holes less massive than this limiting mass scale will show observable flares from both main-sequence and evolved stars, with giants contributing up to 10% of the event rate. The relative fractions of stars disrupted at different evolutionary states can constrain the properties and distributions of stars in galactic nuclei other than our own.

  3. Supermassive Black Holes and their Host Spheroids III. The Mbh-nsph Correlation

    NASA Astrophysics Data System (ADS)

    Savorgnan, Giulia A. D.

    2016-04-01

    The Sérsic {R}1/n model is the best approximation known to date for describing the light distribution of stellar spheroidal and disk components, with the Sérsic index n providing a direct measure of the central radial concentration of stars. The Sérsic index of a galaxy’s spheroidal component, nsph, has been shown to tightly correlate with the mass of the central supermassive black hole, MBH. The {M}{BH}{--}{n}{sph} correlation is also expected from other two well known scaling relations involving the spheroid luminosity, Lsph: the {L}{sph}{--}{n}{sph} and the {M}{BH}{--}{L}{sph}. Obtaining an accurate estimate of the spheroid Sérsic index requires a careful modeling of a galaxy’s light distribution and some studies have failed to recover a statistically significant {M}{BH}{--}{n}{sph} correlation. With the aim of re-investigating the {M}{BH}{--}{n}{sph} and other black hole mass scaling relations, we performed a detailed (i.e., bulge, disks, bars, spiral arms, rings, halo, nucleus, etc.) decomposition of 66 galaxies, with directly measured black hole masses, that had been imaged at 3.6 μm with Spitzer. In this paper, the third of this series, we present an analysis of the {L}{sph}{--}{n}{sph} and {M}{BH}{--}{n}{sph} diagrams. While early-type (elliptical+lenticular) and late-type (spiral) galaxies split into two separate relations in the {L}{sph}{--}{n}{sph} and {M}{BH}{--}{L}{sph} diagrams, they reunite into a single {M}{BH}\\propto {n}{sph}3.39+/- 0.15 sequence with relatively small intrinsic scatter (ε ≃ 0.25 {dex}). The black hole mass appears to be closely related to the spheroid central concentration of stars, which mirrors the inner gradient of the spheroid gravitational potential.

  4. Direct collapse to supermassive black hole seeds: comparing the AMR and SPH approaches

    PubMed Central

    Luo, Yang; Nagamine, Kentaro; Shlosman, Isaac

    2016-01-01

    We provide detailed comparison between the adaptive mesh refinement (AMR) code enzo-2.4 and the smoothed particle hydrodynamics (SPH)/N-body code gadget-3 in the context of isolated or cosmological direct baryonic collapse within dark matter (DM) haloes to form supermassive black holes. Gas flow is examined by following evolution of basic parameters of accretion flows. Both codes show an overall agreement in the general features of the collapse; however, many subtle differences exist. For isolated models, the codes increase their spatial and mass resolutions at different pace, which leads to substantially earlier collapse in SPH than in AMR cases due to higher gravitational resolution in gadget-3. In cosmological runs, the AMR develops a slightly higher baryonic resolution than SPH during halo growth via cold accretion permeated by mergers. Still, both codes agree in the build-up of DM and baryonic structures. However, with the onset of collapse, this difference in mass and spatial resolution is amplified, so evolution of SPH models begins to lag behind. Such a delay can have effect on formation/destruction rate of H2 due to UV background, and on basic properties of host haloes. Finally, isolated non-cosmological models in spinning haloes, with spin parameter λ ∼ 0.01–0.07, show delayed collapse for greater λ, but pace of this increase is faster for AMR. Within our simulation set-up, gadget-3 requires significantly larger computational resources than enzo-2.4 during collapse, and needs similar resources, during the pre-collapse, cosmological structure formation phase. Yet it benefits from substantially higher gravitational force and hydrodynamic resolutions, except at the end of collapse. PMID:27279786

  5. Direct collapse to supermassive black hole seeds: comparing the AMR and SPH approaches

    NASA Astrophysics Data System (ADS)

    Luo, Yang; Nagamine, Kentaro; Shlosman, Isaac

    2016-07-01

    We provide detailed comparison between the adaptive mesh refinement (AMR) code ENZO-2.4 and the smoothed particle hydrodynamics (SPH)/N-body code GADGET-3 in the context of isolated or cosmological direct baryonic collapse within dark matter (DM) haloes to form supermassive black holes. Gas flow is examined by following evolution of basic parameters of accretion flows. Both codes show an overall agreement in the general features of the collapse; however, many subtle differences exist. For isolated models, the codes increase their spatial and mass resolutions at different pace, which leads to substantially earlier collapse in SPH than in AMR cases due to higher gravitational resolution in GADGET-3. In cosmological runs, the AMR develops a slightly higher baryonic resolution than SPH during halo growth via cold accretion permeated by mergers. Still, both codes agree in the build-up of DM and baryonic structures. However, with the onset of collapse, this difference in mass and spatial resolution is amplified, so evolution of SPH models begins to lag behind. Such a delay can have effect on formation/destruction rate of H2 due to UV background, and on basic properties of host haloes. Finally, isolated non-cosmological models in spinning haloes, with spin parameter λ ˜ 0.01-0.07, show delayed collapse for greater λ, but pace of this increase is faster for AMR. Within our simulation set-up, GADGET-3 requires significantly larger computational resources than ENZO-2.4 during collapse, and needs similar resources, during the pre-collapse, cosmological structure formation phase. Yet it benefits from substantially higher gravitational force and hydrodynamic resolutions, except at the end of collapse.

  6. Supermassive black hole seed formation at high redshifts: long-term evolution of the direct collapse

    NASA Astrophysics Data System (ADS)

    Shlosman, Isaac; Choi, Jun-Hwan; Begelman, Mitchell C.; Nagamine, Kentaro

    2016-02-01

    We use cosmological adaptive mesh refinement code ENZO zoom-in simulations to study the long-term evolution of the collapsing gas within dark matter haloes at z. This direct collapse process is a leading candidate for rapid formation of supermassive black hole (SMBH) seeds. To circumvent the Courant condition at small radii, we apply the sink particle method, focusing on evolution on scales ˜0.01-10 pc. The collapse proceeds in two stages, with the secondary runaway happening within the central 10 pc. The sink particles form when the collapsing gas requires additional refinement of the grid size at the highest refinement level. Their growth is negligible with the sole exception of the central seed which grows dramatically to Mseed ˜ 2 × 106 M⊙ in ˜2 Myr, confirming the feasibility of this path to the SMBH. The variability of angular momentum in the accreted gas results in the formation of two misaligned discs. Both discs lie within the Roche limit of the central seed. While the inner disc is geometrically thin and weakly asymmetric, the outer disc flares due to turbulent motions as a result of the massive inflow along a pair of penetrating filaments. The filamentary inflow determines the dominant Fourier modes in this disc - these modes have a non-self-gravitational origin. We do not confirm that m = 1 is a dominant mode that drives the inflow in the presence of a central massive object. The overall configuration appears to be generic, and is expected to form when the central seed becomes sufficiently massive.

  7. Direct Collapse to Supermassive Black Hole Seeds: Comparing the AMR and SPH Approaches

    NASA Astrophysics Data System (ADS)

    Luo, Yang; Nagamine, Kentaro; Shlosman, Isaac

    2016-03-01

    We provide detailed comparison between the AMR code Enzo-2.4 and the SPH/N-body code GADGET-3 in the context of isolated or cosmological direct baryonic collapse within dark matter (DM) halos to form supermassive black holes. Gas flow is examined by following evolution of basic parameters of accretion flows. Both codes show an overall agreement in the general features of the collapse, however, many subtle differences exist. For isolated models, the codes increase their spatial and mass resolutions at different pace, which leads to substantially earlier collapse in SPH than in AMR cases due to higher gravitational resolution in GADGET-3. In cosmological runs, the AMR develops a slightly higher baryonic resolution than SPH during halo growth via cold accretion permeated by mergers. Still, both codes agree in the buildup of DM and baryonic structures. However, with the onset of collapse, this difference in mass and spatial resolution is amplified, so evolution of SPH models begins to lag behind. Such a delay can have effect on formation/destruction rate of H2 due to UV background, and on basic properties of host halos. Finally, isolated non-cosmological models in spinning halos, with spin parameter λ ˜ 0.01 - 0.07, show delayed collapse for greater λ, but pace of this increase is faster for AMR. Within our simulation setup, GADGET-3 requires significantly larger computational resources than Enzo-2.4 during collapse, and needs similar resources, during the pre-collapse, cosmological structure formation phase. Yet it benefits from substantially higher gravitational force and hydrodynamic resolutions, except at the end of collapse.

  8. Supermassive Black Holes in Galactic Nuclei with Tidal Disruption of Stars. II. Axisymmetric Nuclei

    NASA Astrophysics Data System (ADS)

    Zhong, Shiyan; Berczik, Peter; Spurzem, Rainer

    2015-09-01

    The tidal disruption (TD) of stars by supermassive central black holes from dense rotating star clusters is modeled by high-accuracy direct N-body simulations. As in a previous paper on spherical star clusters, we study the time evolution of the stellar tidal disruption rate and the origin of tidally disrupted stars, which are now accorded to several classes of orbits that only occur in axisymmetric systems (short-axis tube and saucer orbits). Compared with that in spherical systems, we found a higher TD rate in axisymmetric systems. The enhancement can be explained by an enlarged loss cone in phase space that stems from the fact that the total angular momentum {\\boldsymbol{J}} is not conserved. As in the case of spherical systems, the distribution of the last apocenter distance of tidally accreted stars peaks at the classical critical radius. However, the angular distribution of the origin of the accreted stars reveals interesting features. Inside the influence radius of the supermassive black hole the angular distribution of disrupted stars has a conspicuous bimodal structure with a local minimum near the equatorial plane. Outside of the influence radius this dependence is weak. We show that the bimodal structure of orbital parameters can be explained by the presence of two families of regular orbits, namely short-axis tube and saucer orbits. Also, we present the consequences of our results for the loss cone in axisymmetric galactic nuclei.

  9. X-RAY CONSTRAINTS ON THE LOCAL SUPERMASSIVE BLACK HOLE OCCUPATION FRACTION

    SciTech Connect

    Miller, Brendan P.; Gallo, Elena; Baldassare, Vivienne; Greene, Jenny E.; Kelly, Brandon C.; Treu, Tommaso; Woo, Jong-Hak

    2015-01-20

    Distinct seed formation mechanisms are imprinted upon the fraction of dwarf galaxies currently containing a central supermassive black hole. Seeding by Population III remnants is expected to produce a higher occupation fraction than is generated with direct gas collapse precursors. Chandra observations of nearby early-type galaxies can directly detect even low-level supermassive black hole activity, and the active fraction immediately provides a firm lower limit to the occupation fraction. Here, we use the volume-limited AMUSE surveys of ∼200 optically selected early-type galaxies to characterize simultaneously, for the first time, the occupation fraction and the scaling of L {sub X} with M {sub star}, accounting for intrinsic scatter, measurement uncertainties, and X-ray limits. For early-type galaxies with M {sub star} < 10{sup 10} M {sub ☉}, we obtain a lower limit to the occupation fraction of >20% (at 95% confidence), but full occupation cannot be excluded. The preferred dependence of log L {sub X} upon log M {sub star} has a slope of ∼0.7-0.8, consistent with the ''downsizing'' trend previously identified from the AMUSE data set, and a uniform Eddington efficiency is disfavored at ∼2σ. We provide guidelines for the future precision with which these parameters may be refined with larger or more sensitive samples.

  10. Searching for GW signals from eccentric supermassive black-hole binaries with pulsar-timing arrays

    NASA Astrophysics Data System (ADS)

    Taylor, Stephen; Gair, Jonathan; Huerta, Eliu; McWilliams, Sean

    2015-04-01

    The mergers of massive galaxies leads to the formation of supermassive black-hole binaries in the common merger remnants. Various mechanisms have been proposed to harden these binaries into the adiabatic GW inspiral regime, from interactions with circumbinary disks to stellar scattering. It may be the case that these mechanisms leave the binary with a residual eccentricity, such that the deviation to the time-of-arrival of pulsar signals induced by the emitted GW passing between the Earth and a pulsar will contain a signature of this eccentricity. Current pulsar-timing search pipelines only probe circular binary systems, but much effort is now being devoted to considering the influence of the binary environment on GW signals. We will detail our efforts in constructing a generalised GW search pipeline to constrain the eccentricity of single systems with arrays of precisely-timed pulsars, which may shed light on the influence of various supermassive black-hole binary hardening mechanisms and illuminate the importance of environmental couplings.

  11. Evolution of binary supermassive black holes and the final-parsec problem

    NASA Astrophysics Data System (ADS)

    Vasiliev, Eugene

    2016-02-01

    I review the evolution of binary supermassive black holes and focus on the stellar-dynamical mechanisms that may help to overcome the final-parsec problem - the possible stalling of the binary at a separation much larger than is required for an efficient gravitational wave emission. Recent N-body simulations have suggested that a departure from spherical symmetry in the nucleus of the galaxy may keep the rate of interaction of stars with the binary at a high enough level so that the binary continues to shrink rather rapidly. However, a major problem of all these simulations is that they do not probe the regime where collisionless effects are dominant - in other words, the number of particles in the simulation is still not sufficient to reach the asymptotic behavior of the system. I present a novel Monte Carlo method for simulating both collisional and collisionless evolution of non-spherical stellar systems, and apply it for the problem of binary supermassive black hole evolution. I show that in triaxial galaxies the final-parsec problem is largely non-existent, while in the axisymmetric case it seems to still exist in the limit of purely collisionless regime relevant for real galaxies, but disappears in the N-body simulations where the feasible values of N are still too low to get rid of collisional effects.

  12. Suppressing star formation in quiescent galaxies with supermassive black hole winds.

    PubMed

    Cheung, Edmond; Bundy, Kevin; Cappellari, Michele; Peirani, Sébastien; Rujopakarn, Wiphu; Westfall, Kyle; Yan, Renbin; Bershady, Matthew; Greene, Jenny E; Heckman, Timothy M; Drory, Niv; Law, David R; Masters, Karen L; Thomas, Daniel; Wake, David A; Weijmans, Anne-Marie; Rubin, Kate; Belfiore, Francesco; Vulcani, Benedetta; Chen, Yan-mei; Zhang, Kai; Gelfand, Joseph D; Bizyaev, Dmitry; Roman-Lopes, A; Schneider, Donald P

    2016-05-26

    Quiescent galaxies with little or no ongoing star formation dominate the population of galaxies with masses above 2 × 10(10) times that of the Sun; the number of quiescent galaxies has increased by a factor of about 25 over the past ten billion years (refs 1-4). Once star formation has been shut down, perhaps during the quasar phase of rapid accretion onto a supermassive black hole, an unknown mechanism must remove or heat the gas that is subsequently accreted from either stellar mass loss or mergers and that would otherwise cool to form stars. Energy output from a black hole accreting at a low rate has been proposed, but observational evidence for this in the form of expanding hot gas shells is indirect and limited to radio galaxies at the centres of clusters, which are too rare to explain the vast majority of the quiescent population. Here we report bisymmetric emission features co-aligned with strong ionized-gas velocity gradients from which we infer the presence of centrally driven winds in typical quiescent galaxies that host low-luminosity active nuclei. These galaxies are surprisingly common, accounting for as much as ten per cent of the quiescent population with masses around 2 × 10(10) times that of the Sun. In a prototypical example, we calculate that the energy input from the galaxy's low-level active supermassive black hole is capable of driving the observed wind, which contains sufficient mechanical energy to heat ambient, cooler gas (also detected) and thereby suppress star formation. PMID:27225122

  13. Warping and tearing of misaligned circumbinary disks around eccentric supermassive black hole binaries

    NASA Astrophysics Data System (ADS)

    Hayasaki, K.; Sohn, B. W.; Okazaki, A. T.; Jung, T.; Zhao, G.; Naito, T.

    2015-07-01

    We study the warping and tearing of a geometrically thin, non-self-gravitating disk surrounding binary supermassive black holes on an eccentric orbit. The circumbinary disk is significantly misaligned with the binary orbital plane, and is subject to the time-dependent tidal torques. In principle, such a disk is warped and precesses, and is torn into mutually misaligned rings in the region, where the tidal precession torques are stronger than the local viscous torques. We derive the tidal-warp and tearing radii of the misaligned circumbinary disks around eccentric SMBH binaries. We find that in disks with the viscosity parameter α larger than a critical value depending on the disk aspect ratio, the disk warping appears outside the tearing radius. This condition is expressed for small amplitude warps as α > √H/(3r) for H/rlesssim0.1, where H is the disk scale height. If α < √H/(3r), only the disk tearing occurs because the tidal warp radius is inside the tearing radius, where most of disk material is likely to rapidly accrete onto SMBHs. In warped and torn disks, both the tidal-warp and the tearing radii most strongly depend on the binary semi-major axis, although they also mildly depend on the other orbital and disk parameters. This strong dependence enables us to estimate the semi-major axis, once the tidal warp or tearing radius is determined observationally: for the tidal warp radius of 0.1 pc, the semi-major axis is estimated to be ~10-2 pc for 107 Msolar black hole with typical orbital and disk parameters. We also briefly discuss the possibility that central objects of observed warped maser disks in active galactic nuclei are supermassive black hole binaries.

  14. Suppressing star formation in quiescent galaxies with supermassive black hole winds

    NASA Astrophysics Data System (ADS)

    Cheung, Edmond; Bundy, Kevin; Cappellari, Michele; Peirani, Sébastien; Rujopakarn, Wiphu; Westfall, Kyle; Yan, Renbin; Bershady, Matthew; Greene, Jenny E.; Heckman, Timothy M.; Drory, Niv; Law, David R.; Masters, Karen L.; Thomas, Daniel; Wake, David A.; Weijmans, Anne-Marie; Rubin, Kate; Belfiore, Francesco; Vulcani, Benedetta; Chen, Yan-Mei; Zhang, Kai; Gelfand, Joseph D.; Bizyaev, Dmitry; Roman-Lopes, A.; Schneider, Donald P.

    2016-05-01

    Quiescent galaxies with little or no ongoing star formation dominate the population of galaxies with masses above 2 × 1010 times that of the Sun; the number of quiescent galaxies has increased by a factor of about 25 over the past ten billion years (refs 1, 2, 3, 4). Once star formation has been shut down, perhaps during the quasar phase of rapid accretion onto a supermassive black hole, an unknown mechanism must remove or heat the gas that is subsequently accreted from either stellar mass loss or mergers and that would otherwise cool to form stars. Energy output from a black hole accreting at a low rate has been proposed, but observational evidence for this in the form of expanding hot gas shells is indirect and limited to radio galaxies at the centres of clusters, which are too rare to explain the vast majority of the quiescent population. Here we report bisymmetric emission features co-aligned with strong ionized-gas velocity gradients from which we infer the presence of centrally driven winds in typical quiescent galaxies that host low-luminosity active nuclei. These galaxies are surprisingly common, accounting for as much as ten per cent of the quiescent population with masses around 2 × 1010 times that of the Sun. In a prototypical example, we calculate that the energy input from the galaxy’s low-level active supermassive black hole is capable of driving the observed wind, which contains sufficient mechanical energy to heat ambient, cooler gas (also detected) and thereby suppress star formation.

  15. CO-EVOLUTION OF SUPERMASSIVE BLACK HOLE AND HOST GALAXY FROM z {approx} 1 TO z = 0

    SciTech Connect

    Kiuchi, Gaku; Ohta, Kouji; Akiyama, Masayuki

    2009-05-01

    Stellar masses of bulges in hosts of active galactic nuclei (AGNs) and black hole masses in the AGNs are derived at z = 0.5-1.15 to study evolution of the black hole-to-bulge mass relation. In order to derive bulge stellar masses, we use a sample of type-2 AGNs to avoid the bright nuclear light. 34 type-2 AGNs are selected from the spectroscopically identified X-ray sources in the Chandra Deep Field South. We use optical images from the Hubble Space Telescope, and near- and mid-infrared photometry from the Very Large Telescope and the Spitzer Space Telescope. The bulge components are derived by fitting the two-dimensional surface brightness model consisting of a bulge and a disk component to the optical images. We derive stellar masses (M {sub bulge}) and star formation rates (SFRs) of the bulge components by spectral energy distribution fitting. The derived M {sub bulge} ranges over 10{sup 9}-10{sup 11} M {sub sun}, and the estimated SFR is 0.01-100 M {sub sun} yr{sup -1}. Masses of supermassive black holes (SMBHs; M {sub .}) and black hole accretion rates (BHARs) are estimated with the absorption-corrected X-ray luminosities in the 2-10 keV band under an assumption of the constant Eddington ratio of 0.1 and the constant energy conversion factor of 0.1. Resulting black hole masses and BHARs range over 10{sup 5.5}-10{sup 8} M {sub sun} and 0.001-1 M {sub sun} yr{sup -1}, respectively. For luminous AGNs, the estimated M {sub .}/M {sub bulge} ratio is {approx}4 x 10{sup -4} in the median, which is lower than that for local galaxies and for type-2 AGNs at z {approx} 0.2. However, these differences are within uncertainty and are not significant. This can imply that SMBHs and their host galaxies are evolving almost holding the constant M {sub .}/M {sub bulge} ratio from z {approx} 1.0 to 0 in a cosmological timescale. Meanwhile, the estimated BHAR/SFR ratio is about 60 times larger than the M {sub .}/M {sub bulge} ratio in the median value. This indicates that growths

  16. A STRONGLY MAGNETIZED PULSAR WITHIN THE GRASP OF THE MILKY WAY'S SUPERMASSIVE BLACK HOLE

    SciTech Connect

    Rea, N.; Torres, D. F.; Papitto, A.; Camero-Arranz, A.; Esposito, P.; Mereghetti, S.; Tiengo, A.; Pons, J. A.; Viganò, D.; Turolla, R.; Israel, G. L.; Stella, L.; Possenti, A.; Burgay, M.; Perna, R.; Ponti, G.; Baganoff, F. K.; Haggard, D.; Zane, S.; Minter, A.; and others

    2013-10-01

    The center of our Galaxy hosts a supermassive black hole, Sagittarius (Sgr) A*. Young, massive stars within 0.5 pc of Sgr A* are evidence of an episode of intense star formation near the black hole a few million years ago, which might have left behind a young neutron star traveling deep into Sgr A*'s gravitational potential. On 2013 April 25, a short X-ray burst was observed from the direction of the Galactic center. With a series of observations with the Chandra and the Swift satellites, we pinpoint the associated magnetar at an angular distance of 2.4 ± 0.3 arcsec from Sgr A*, and refine the source spin period and its derivative (P = 3.7635537(2) s and P-dot = 6.61(4)×10{sup -12} s s{sup –1}), confirmed by quasi simultaneous radio observations performed with the Green Bank Telescope and Parkes Radio Telescope, which also constrain a dispersion measure of DM = 1750 ± 50 pc cm{sup –3}, the highest ever observed for a radio pulsar. We have found that this X-ray source is a young magnetar at ≈0.07-2 pc from Sgr A*. Simulations of its possible motion around Sgr A* show that it is likely (∼90% probability) in a bound orbit around the black hole. The radiation front produced by the past activity from the magnetar passing through the molecular clouds surrounding the Galactic center region might be responsible for a large fraction of the light echoes observed in the Fe fluorescence features.

  17. Do Circumnuclear Dense Gas Disks Drive Mass Accretion onto Supermassive Black Holes?

    NASA Astrophysics Data System (ADS)

    Izumi, Takuma; Kawakatu, Nozomu; Kohno, Kotaro

    2016-08-01

    We present a positive correlation between the mass of dense molecular gas ({M}{{dense}}) of ∼100 pc scale circumnuclear disks (CNDs) and the black hole mass accretion rate ({\\dot{M}}{{BH}}) in a total of 10 Seyfert galaxies, based on data compiled from the literature and an archive (median aperture θ med = 220 pc). A typical {M}{{dense}} of CNDs is 107–8 {M}ȯ , estimated from the luminosity of the dense gas tracer, the HCN(1–0) emission line. Because dense molecular gas is the site of star formation, this correlation is virtually equivalent to the one between the nuclear star-formation rate and {\\dot{M}}{{BH}} revealed previously. Moreover, the {M}{{dense}}{--}{\\dot{M}}{{BH}} correlation was tighter for CND-scale gas than for the gas on kiloparsec or larger scales. This indicates that CNDs likely play an important role in fueling black holes, whereas greater than kiloparesec scale gas does not. To demonstrate a possible approach for studying the CND-scale accretion process with the Atacama Large Millimeter/submillimeter Array, we used a mass accretion model where angular momentum loss due to supernova explosions is vital. Based on the model prediction, we suggest that only the partial fraction of the mass accreted from the CND ({\\dot{M}}{{acc}}) is consumed as {\\dot{M}}{{BH}}. However, {\\dot{M}}{{acc}} agrees well with the total nuclear mass flow rate (i.e., {\\dot{M}}{{BH}} + outflow rate). Although these results are still tentative with large uncertainties, they support the view that star formation in CNDs can drive mass accretion onto supermassive black holes in Seyfert galaxies.

  18. Evidence of a Supermassive Black Hole in the Galaxy NGC 1023 From The Nuclear Stellar Dynamics

    NASA Technical Reports Server (NTRS)

    Bower, G. A.; Green, R. F.; Bender, R.; Gebhardt, K.; Lauer, T. R.; Magorrian, J.; Richstone, D. O.; Danks, A.; Gull, T.; Hutchings, J.

    2000-01-01

    We analyze the nuclear stellar dynamics of the SBO galaxy NGC 1023, utilizing observational data both from the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope and from the ground. The stellar kinematics measured from these long-slit spectra show rapid rotation (V equals approx. 70 km/s at a distance of O.1 deg = 4.9 pc from the nucleus) and increasing velocity dispersion toward the nucleus (where sigma = 295 +/- 30 km/s). We model the observed stellar kinematics assuming an axisymmetric mass distribution with both two and three integrals of motion. Both modeling techniques point to the presence of a central dark compact mass (which presumably is a supermassive black hole) with confidence > 99%. The isotropic two-integral models yield a best-fitting black hole mass of (6.0 +/- 0.4) x 10(exp 7) solar masses and mass-to-light ratio (M/L(sub v)) of 5.38 +/- 0.08, and the goodness-of-fit (CHI(exp 2)) is insensitive to reasonable values for the galaxy's inclination. The three-integral models, which non-parametrically fit the observed line-of-sight velocity distribution as a function of position in the galaxy, suggest a black hole mass of (3.9 +/- 0.4) x 10(exp 7) solar masses and M/L(sub v) of 5.56 +/- 0.02 (internal errors), and the edge-on models are vastly superior fits over models at other inclinations. The internal dynamics in NGC 1023 as suggested by our best-fit three-integral model shows that the velocity distribution function at the nucleus is tangentially anisotropic, suggesting the presence of a nuclear stellar disk. The nuclear line of sight velocity distribution has enhanced wings at velocities >= 600 km/s from systemic, suggesting that perhaps we have detected a group of stars very close to the central dark mass.

  19. Do Circumnuclear Dense Gas Disks Drive Mass Accretion onto Supermassive Black Holes?

    NASA Astrophysics Data System (ADS)

    Izumi, Takuma; Kawakatu, Nozomu; Kohno, Kotaro

    2016-08-01

    We present a positive correlation between the mass of dense molecular gas ({M}{{dense}}) of ˜100 pc scale circumnuclear disks (CNDs) and the black hole mass accretion rate ({\\dot{M}}{{BH}}) in a total of 10 Seyfert galaxies, based on data compiled from the literature and an archive (median aperture θ med = 220 pc). A typical {M}{{dense}} of CNDs is 107–8 {M}ȯ , estimated from the luminosity of the dense gas tracer, the HCN(1–0) emission line. Because dense molecular gas is the site of star formation, this correlation is virtually equivalent to the one between the nuclear star-formation rate and {\\dot{M}}{{BH}} revealed previously. Moreover, the {M}{{dense}}{--}{\\dot{M}}{{BH}} correlation was tighter for CND-scale gas than for the gas on kiloparsec or larger scales. This indicates that CNDs likely play an important role in fueling black holes, whereas greater than kiloparesec scale gas does not. To demonstrate a possible approach for studying the CND-scale accretion process with the Atacama Large Millimeter/submillimeter Array, we used a mass accretion model where angular momentum loss due to supernova explosions is vital. Based on the model prediction, we suggest that only the partial fraction of the mass accreted from the CND ({\\dot{M}}{{acc}}) is consumed as {\\dot{M}}{{BH}}. However, {\\dot{M}}{{acc}} agrees well with the total nuclear mass flow rate (i.e., {\\dot{M}}{{BH}} + outflow rate). Although these results are still tentative with large uncertainties, they support the view that star formation in CNDs can drive mass accretion onto supermassive black holes in Seyfert galaxies.

  20. High-redshift quasars and the supermassive black hole mass budget: constraints on quasar formation models

    NASA Astrophysics Data System (ADS)

    Bromley, J. M.; Somerville, R. S.; Fabian, A. C.

    2004-05-01

    We investigate the constraints on models of supermassive black hole (SMBH) and quasar formation obtainable from two recent observational developments: the discovery of luminous quasars at z~ 6, and estimates of the local mass density of SMBHs. If ~90 per cent of this mass was accreted at redshifts z<~ 3, as suggested by the observed quasar luminosity functions, these joint constraints pose a challenge for models, which must account for the observed luminous quasar population at z~ 6 within a very limited `mass budget'. We investigate a class of models based within the hierarchical structure formation scenario, in which major mergers lead to black hole formation and fuelling, and the resulting quasars shine at their Eddington-limited rate until their fuel is exhausted. We show that the simplest such model, in which a constant fraction of the gas within the halo is accreted in each major merger, cannot satisfy both constraints simultaneously. When this model is normalized to reproduce the number density of luminous quasars at z~ 6, the mass budget is grossly exceeded owing to an overabundance of lower-mass SMBHs. We explore a range of modifications to the simple model designed to overcome this problem. We show that both constraints can be satisfied if the gas accretion fraction scales as a function of the halo virial velocity. Similar scalings have been proposed in order to reproduce the local M•-σ relation. Successful models can also be constructed by restricting the formation of seed black holes to redshifts above zcrit~ 11.5 or to haloes above a velocity threshold vcrit~ 55 km s-1, or assuming that only a fraction of major mergers result in formation of a seed SMBH. We also briefly discuss the issue of trying to assume a `universal M•-σ relation' within the framework of simple Press-Schechter models, and further show that a fixed universal relation between SMBH mass and host halo mass is unlikely.

  1. The SINFONI Black Hole Survey: The Black Hole Fundamental Plane Revisited and the Paths of (Co)evolution of Supermassive Black Holes and Bulges

    NASA Astrophysics Data System (ADS)

    Saglia, R. P.; Opitsch, M.; Erwin, P.; Thomas, J.; Beifiori, A.; Fabricius, M.; Mazzalay, X.; Nowak, N.; Rusli, S. P.; Bender, R.

    2016-02-01

    We investigate the correlations between the black hole (BH) mass MBH, the velocity dispersion σ, the bulge mass MBu, the bulge average spherical density {ρ }{{h}}, and its spherical half-mass radius rh, constructing a database of 97 galaxies (31 core ellipticals, 17 power-law ellipticals, 30 classical bulges, and 19 pseudobulges) by joining 72 galaxies from the literature to 25 galaxies observed during our recent SINFONI BH survey. For the first time we discuss the full error covariance matrix. We analyze the well-known MBH-σ and MBH-MBu relations and establish the existence of statistically significant correlations between MBu and rh and anticorrelations between MBu and {ρ }{{h}}. We establish five significant bivariate correlations (MBH-σ-ρh, MBH-σ-rh, MBH-MBu-σ, MBH-MBu-ρh, MBH-MBu-rh) that predict MBH of 77 core and power-law ellipticals and classical bulges with measured and intrinsic scatter as small as ≈ 0.36 dex and ≈ 0.33 dex, respectively, or 0.26 dex when the subsample of 45 galaxies defined by Kormendy & Ho is considered. In contrast, pseudobulges have systematically lower MBH but approach the predictions of all of the above relations at spherical densities {ρ }{{h}}≥slant {10}10 {M}⊙ {{kpc}}-3 or scale lengths {r}{{h}}≤slant 1 {{kpc}}. These findings fit in a scenario of coevolution of BH and classical-bulge masses, where core ellipticals are the product of dry mergers of power-law bulges and power-law ellipticals and bulges the result of (early) gas-rich mergers and of disk galaxies. In contrast, the (secular) growth of BHs is decoupled from the growth of their pseudobulge hosts, except when (gas) densities are high enough to trigger the feedback mechanism responsible for the existence of the correlations between MBH and galaxy structural parameters.

  2. The origin and growth of the first black holes

    NASA Astrophysics Data System (ADS)

    Schawinski, Kevin

    2015-08-01

    I will present recent results on the search for black hole growth at the highest redshifts in the deepest Chandra X-ray observations: a startling lack of faint AGN in z>5 galaxies is starting to place interesting constraints on formation and early growth scenarios. At the same time, circumstantial evidence from both observations and theory points to late formation of black hole seeds in moderate mass galaxies as a viable channel. Dense sub-galactic clumps and major mergers are plausible formation sites perhaps even to z~0. I will also present the outlook for future X-ray missions such as ATHENA in tracing black hole growth at unprecedented levels using X-ray variability.

  3. Evidence for Supermassive Black Holes in Active Galactic Nuclei from Emission-Line Reverberation

    NASA Technical Reports Server (NTRS)

    Peterson, Bradley M.; Wandel, Amri

    2000-01-01

    Emission-line variability data for Seyfert 1 galaxies provide strong evidence for the existence of supermassive black holes in the nuclei of these galaxies and that the line-emitting gas is moving in the gravitational potential of that black hole. The time-delayed response of the emission lines to continuum variations is used to infer the size of the line-emitting region, which is then combined with measurements of the Doppler widths of the variable line components to estimate a virial mass. la the case of the best-studied galaxy, NGC 5548, various emission lines spanning an order of magnitude in distance from the central source show the expected V proportional to r(sup -l/2) correlation between distance and line width and are thus consistent with a single value for the mass. Two other Seyfert galaxies, NGC 7469 and 3C 390.3, show a similar relationship. We compute the ratio of luminosity to mass for these three objects and the narrow-line Seyfert I galaxy NGC 4051 and find that the gravitational force on the line-emitting gas is much stronger than radiation pressure. These results strongly support the paradigm of gravitationally bound broad emission line region clouds.

  4. A three-stage search for supermassive black-hole binaries in LISA data

    NASA Astrophysics Data System (ADS)

    Brown, Duncan A.; Crowder, Jeff; Cutler, Curt; Mandel, Ilya; Vallisneri, Michele

    2007-10-01

    Gravitational waves from the inspiral and coalescence of supermassive black-hole (SMBH) binaries with masses m1 ~ m2 ~ 106Modot are likely to be among the strongest sources for the Laser Interferometer Space Antenna (LISA). We describe a three-stage data-analysis pipeline designed to search for and measure the parameters of SMBH binaries in LISA data. The first stage uses a time frequency track-search method to search for inspiral signals and provide a coarse estimate of the black-hole masses m1, m2 and the coalescence time of the binary tc. The second stage uses a sequence of matched-filter template banks, seeded by the first stage, to improve the measurement accuracy of the masses and coalescence time. Finally, a Markov chain Monte Carlo search is used to estimate all nine physical parameters of the binary (masses, coalescence time, distance, initial phase, sky position and orientation). Using results from the second stage substantially shortens the Markov chain burn-in time and allows us to determine the number of SMBH-binary signals in the data before starting parameter estimation. We demonstrate our analysis pipeline using simulated data from the first Mock LISA Data Challenge. We discuss our plan for improving this pipeline and the challenges that will be faced in real LISA data analysis.

  5. SUPERMASSIVE BLACK HOLE BINARY EVOLUTION IN AXISYMMETRIC GALAXIES: THE FINAL PARSEC PROBLEM IS NOT A PROBLEM

    SciTech Connect

    Khan, Fazeel Mahmood; Holley-Bockelmann, Kelly; Berczik, Peter; Just, Andreas E-mail: just@ari.uni-heidelberg.de E-mail: k.holley@vanderbilt.edu

    2013-08-20

    During a galaxy merger, the supermassive black hole (SMBH) in each galaxy is thought to sink to the center of the potential and form an SMBH binary; this binary can eject stars via three-body scattering, bringing the SMBHs ever closer. In a static spherical galaxy model, the binary stalls at a separation of about a parsec after ejecting all the stars in its loss cone-this is the well-known final parsec problem. Earlier work has shown that the centrophilic orbits in triaxial galaxy models are key in refilling the loss cone at a high enough rate to prevent the black holes from stalling. However, the evolution of binary SMBHs has never been explored in axisymmetric galaxies, so it is not clear if the final parsec problem persists in these systems. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in galaxy models with a range of ellipticity. For the first time, we show that mere axisymmetry can solve the final parsec problem; we find the SMBH evolution is independent of N for an axis ratio of c/a = 0.8, and that the SMBH binary separation reaches the gravitational radiation regime for c/a = 0.75.

  6. Supermassive Black Hole Binary Evolution in Axisymmetric Galaxies: The Final Parsec Problem is Not a Problem

    NASA Astrophysics Data System (ADS)

    Khan, Fazeel Mahmood; Holley-Bockelmann, Kelly; Berczik, Peter; Just, Andreas

    2013-08-01

    During a galaxy merger, the supermassive black hole (SMBH) in each galaxy is thought to sink to the center of the potential and form an SMBH binary; this binary can eject stars via three-body scattering, bringing the SMBHs ever closer. In a static spherical galaxy model, the binary stalls at a separation of about a parsec after ejecting all the stars in its loss cone—this is the well-known final parsec problem. Earlier work has shown that the centrophilic orbits in triaxial galaxy models are key in refilling the loss cone at a high enough rate to prevent the black holes from stalling. However, the evolution of binary SMBHs has never been explored in axisymmetric galaxies, so it is not clear if the final parsec problem persists in these systems. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in galaxy models with a range of ellipticity. For the first time, we show that mere axisymmetry can solve the final parsec problem; we find the SMBH evolution is independent of N for an axis ratio of c/a = 0.8, and that the SMBH binary separation reaches the gravitational radiation regime for c/a = 0.75.

  7. Impact of baryonic streaming velocities on the formation of supermassive black holes via direct collapse

    NASA Astrophysics Data System (ADS)

    Latif, M. A.; Niemeyer, J. C.; Schleicher, D. R. G.

    2014-06-01

    Baryonic streaming motions produced prior to the epoch of recombination became supersonic during the cosmic dark ages. Various studies suggest that such streaming velocities change the halo statistics and also influence the formation of Population III stars. In this study, we aim to explore the impact of streaming velocities on the formation of supermassive black holes at z>10 via the direct collapse scenario. To accomplish this goal, we perform cosmological large eddy simulations for two haloes of a few times 107M⊙ with initial streaming velocities of 3, 6 and 9 km s-1. These massive primordial haloes illuminated by the strong Lyman-Werner flux are the potential cradles for the formation of direct collapse seed black holes. To study the evolution for longer times, we employ sink particles and track the accretion for 10 000 years. Our findings show that higher streaming velocities increase the circular velocities from about 14 to 16 km s-1. They also delay the collapse of haloes for a few million years, but do not have any significant impact on the halo properties such as turbulent energy, radial velocity, density and accretion rates. Sink particles of about ˜105M⊙ are formed at the end of our simulations and no clear distribution of sink masses is observed in the presence of streaming motions. It is further found that the impact of streaming velocities is less severe in massive haloes compared to the minihaloes as reported in the previous studies.

  8. UPDATED MASS SCALING RELATIONS FOR NUCLEAR STAR CLUSTERS AND A COMPARISON TO SUPERMASSIVE BLACK HOLES

    SciTech Connect

    Scott, Nicholas; Graham, Alister W.

    2013-02-15

    We investigate whether or not nuclear star clusters and supermassive black holes (SMBHs) follow a common set of mass scaling relations with their host galaxy's properties, and hence can be considered to form a single class of central massive object (CMO). We have compiled a large sample of galaxies with measured nuclear star cluster masses and host galaxy properties from the literature and fit log-linear scaling relations. We find that nuclear star cluster mass, M {sub NC}, correlates most tightly with the host galaxy's velocity dispersion: log M {sub NC} = (2.11 {+-} 0.31)log ({sigma}/54) + (6.63 {+-} 0.09), but has a slope dramatically shallower than the relation defined by SMBHs. We find that the nuclear star cluster mass relations involving host galaxy (and spheroid) luminosity and stellar and dynamical mass, intercept with but are in general shallower than the corresponding black hole scaling relations. In particular, M {sub NC}{proportional_to}M {sup 0.55{+-}0.15} {sub Gal,dyn}; the nuclear cluster mass is not a constant fraction of its host galaxy or spheroid mass. We conclude that nuclear stellar clusters and SMBHs do not form a single family of CMOs.

  9. THE M {sub BH}-L {sub SPHEROID} RELATION AT HIGH AND LOW MASSES, THE QUADRATIC GROWTH OF BLACK HOLES, AND INTERMEDIATE-MASS BLACK HOLE CANDIDATES

    SciTech Connect

    Graham, Alister W.; Scott, Nicholas

    2013-02-20

    From a sample of 72 galaxies with reliable supermassive black hole masses M {sub bh}, we derive the M {sub bh}-(host spheroid luminosity, L) relation for (1) the subsample of 24 core-Sersic galaxies with partially depleted cores, and (2) the remaining subsample of 48 Sersic galaxies. Using K{sub s} -band Two Micron All Sky Survey data, we find the near-linear relation M {sub bh}{proportional_to}L {sup 1.10{+-}0.20} {sub K{sub s}} for the core-Sersic spheroids thought to be built in additive dry merger events, while we find the relation M {sub bh}{proportional_to}L {sup 2.73{+-}0.55}{sub K{sub s}} for the Sersic spheroids built from gas-rich processes. After converting literature B-band disk galaxy magnitudes into inclination- and dust-corrected bulge magnitudes, via a useful new equation presented herein, we obtain a similar result. Unlike with the M {sub bh}-(velocity dispersion) diagram, which is also updated here using the same galaxy sample, it remains unknown whether barred and non-barred Sersic galaxies are offset from each other in the M {sub bh}-L diagram. While black hole feedback has typically been invoked to explain what was previously thought to be a nearly constant M {sub bh}/M {sub Spheroid} mass ratio of {approx}0.2%, we advocate that the near-linear M {sub bh}-L and M {sub bh}-M {sub Spheroid} relations observed at high masses may have instead arisen largely from the additive dry merging of galaxies. We argue that feedback results in a dramatically different scaling relation, such that black hole mass scales roughly quadratically with the spheroid mass in Sersic galaxies. We therefore introduce a revised cold-gas 'quasar' mode feeding equation for semi-analytical models to reflect what we dub the quadratic growth of black holes in Sersic galaxies built amidst gas-rich processes. Finally, we use our new Sersic M {sub bh}-L equations to predict the masses of candidate intermediate mass black holes in almost 50 low-luminosity spheroids containing

  10. Multi-messenger Efforts in the Search for Supermassive Black Hole Pairs

    NASA Astrophysics Data System (ADS)

    Spolaor, Sarah; LAZIO, J.; Pulsar Timing Array, Parkes

    2013-01-01

    A number of electromagnetic phenomena have been suggested to imply the presence of a supermassive black hole (SMBH) binary in the emission's host galaxy. No systems have been conclusively demonstrated to be a close binary (i.e. orbital periods <100 years, orbital separations < 30pc), despite that a positive identification would contribute to knowledge of the expected gravitational waveform from these objects and their role in cosmic evolution. We consider several cases where radio imaging on pc to kpc scales can clarify purported signatures of SMBH pairs or binaries. In some cases, pulsar timing's limits on gravitational waves from these systems can provide a powerful means to constrain, support, or disprove a binary SMBH hypothesis, and/or provide constraints on the origin of larger-scale jet behaviours in AGN. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  11. Compact symmetric objects and supermassive binary black holes in the VLBA Imaging and Polarimetry Survey

    NASA Astrophysics Data System (ADS)

    Tremblay, S. E.; Taylor, G. B.; Ortiz, A. A.; Tremblay, C. D.; Helmboldt, J. F.; Romani, R. W.

    2016-06-01

    We present multifrequency Very Long Baseline Array (VLBA) follow-up observations of VLBA Imaging and Polarimetry Survey sources identified as likely compact symmetric objects (CSOs) or supermassive binary black holes (SBBHs). We also present new spectroscopic redshifts for 11 sources observed with the Hobby-Eberly Telescope. While no new SBBHs can be confirmed from these observations, we have identified 24 CSOs in the sample, 15 of which are newly designated, and refuted 52 candidates leaving 33 unconfirmed candidates. This is the first large uniform sample of CSOs which can be used to elicit some of the general properties of these sources, including morphological evolution and environmental interaction. We have detected polarized emission from two of these CSOs the properties of which are consistent with active galactic nuclei unification schemes.

  12. MILKY WAY SUPERMASSIVE BLACK HOLE: DYNAMICAL FEEDING FROM THE CIRCUMNUCLEAR ENVIRONMENT

    SciTech Connect

    Liu, Hauyu Baobab; Hsieh, Pei-Ying; Ho, Paul T. P.; Su, Yu-Nung; Wright, Melvyn; Sun, Ai-Lei; Minh, Young Chol

    2012-09-10

    The supermassive black hole (SMBH), Sgr A*, at the Galactic center is surrounded by a molecular circumnuclear disk (CND) lying between 1.5 and 4 pc radii. The irregular and clumpy structures of the CND suggest dynamical evolution and episodic feeding of gas toward the central SMBH. New sensitive data from the Submillimeter Array and Green Bank Telescope reveal several >5-10 pc scale molecular arms, which either directly connect to the CND or may penetrate inside the CND. The CND appears to be the convergence of the innermost parts of large-scale gas streamers, which are responding to the central gravitational potential well. Rather than being a quasi-stationary structure, the CND may be dynamically evolving, incorporating inflow via streamers, and feeding gas toward the center.

  13. On the detection of eccentric supermassive black hole binaries with pulsar timing arrays

    NASA Astrophysics Data System (ADS)

    Huerta, Eliu; McWilliams, Sean; Gair, Jonathan; Taylor, Stephen

    2015-04-01

    It is believed that supermassive black holes (SMBHs) with masses between a million up to a few billion solar masses are ubiquitous in nearby galactic nuclei. Hence, the merger of a pair of galaxies hosting these compact objects may result in the formation of a compact binary that decays to small orbital separations via interactions with its stellar and gaseous environments. Recent studies suggest that these formation channels imply that SMBH binaries may have large orbital eccentricities when they become dominated by gravitational wave emission. In light of these considerations, we present a novel and comprehensive framework that we put at work to carry out an end-to-end analysis of the effect of eccentricity on the amplitude and spectrum of a stochastic, isotropic gravitational wave background from SMBH binaries and single resolvable sources that may be detected with Pulsar Timing Arrays.

  14. MULTIPLE TIDAL DISRUPTIONS AS AN INDICATOR OF BINARY SUPERMASSIVE BLACK HOLE SYSTEMS

    SciTech Connect

    Wegg, Christopher; Nate Bode, J.

    2011-09-01

    We find that the majority of systems hosting multiple tidal disruptions (TDs) are likely to contain hard binary supermassive black hole (SMBH) systems, and also show that the rates of these repeated events are high enough to be detected by the Large Synoptic Survey Telescope (LSST) over its lifetime. Therefore, these multiple TD events provide a novel method for identifying SMBH binary systems with parsec to subparsec separations. The rates of TDs are investigated using simulations of non-interacting stars initially orbiting a primary SMBH and the potential of the model stellar cusp. The stars are then evolved forward in time and perturbed by a secondary SMBH inspiraling from the edge of the cusp to its stalling radius. We find with conservative magnitude estimates that the next-generation transient survey LSST should detect multiple TDs in approximately three galaxies over five years of observation, though less conservative estimates could increase this rate by an order of magnitude.

  15. Gravitational waves from binary supermassive black holes missing in pulsar observations.

    PubMed

    Shannon, R M; Ravi, V; Lentati, L T; Lasky, P D; Hobbs, G; Kerr, M; Manchester, R N; Coles, W A; Levin, Y; Bailes, M; Bhat, N D R; Burke-Spolaor, S; Dai, S; Keith, M J; Osłowski, S; Reardon, D J; van Straten, W; Toomey, L; Wang, J-B; Wen, L; Wyithe, J S B; Zhu, X-J

    2015-09-25

    Gravitational waves are expected to be radiated by supermassive black hole binaries formed during galaxy mergers. A stochastic superposition of gravitational waves from all such binary systems would modulate the arrival times of pulses from radio pulsars. Using observations of millisecond pulsars obtained with the Parkes radio telescope, we constrained the characteristic amplitude of this background, A(c,yr), to be <1.0 × 10(-15) with 95% confidence. This limit excludes predicted ranges for A(c,yr) from current models with 91 to 99.7% probability. We conclude that binary evolution is either stalled or dramatically accelerated by galactic-center environments and that higher-cadence and shorter-wavelength observations would be more sensitive to gravitational waves. PMID:26404832

  16. Soft gamma-ray constraints on a bright flare from the Galactic Center supermassive black hole

    NASA Astrophysics Data System (ADS)

    Trap, G.; Goldwurm, A.; Terrier, R.; Dodds-Eden, K.; Gillessen, S.; Genzel, R.; Pantin, E.; Lagage, P. O.; Ferrando, P.; Bélanger, G.; Porquet, D.; Grosso, N.; Yusef-Zadeh, F.; Melia, F.

    2010-02-01

    Sagittarius A★(SgrA★) is the supermassive black hole residing at the center of the Milky Way. It has been the main target of an extensive multiwavelength campaign we carried out in April 2007. Herein, we report the detection of a bright flare from the vicinity of the horizon, observed simultaneously in X-rays (XMM-Newton/EPIC) and near infrared (VLT/NACO) on April 4th for 1-2 h. For the first time, such an event also benefitted from a soft γ-rays (INTEGRAL/ISGRI) and mid infrared (VLT/VISIR) coverage, which enabled us to derive upper limits at both ends of the flare spectral energy distribution (SED). We discuss the physical implications of the contemporaneous light curves as well as the SED, in terms of synchrotron, synchrotron self-Compton and external Compton emission processes.

  17. Milky Way Supermassive Black Hole: Dynamical Feeding from the Circumnuclear Environment

    NASA Astrophysics Data System (ADS)

    Liu, Hauyu Baobab; Hsieh, Pei-Ying; Ho, Paul T. P.; Su, Yu-Nung; Wright, Melvyn; Sun, Ai-Lei; Minh, Young Chol

    2012-09-01

    The supermassive black hole (SMBH), Sgr A*, at the Galactic center is surrounded by a molecular circumnuclear disk (CND) lying between 1.5 and 4 pc radii. The irregular and clumpy structures of the CND suggest dynamical evolution and episodic feeding of gas toward the central SMBH. New sensitive data from the Submillimeter Array and Green Bank Telescope reveal several >5-10 pc scale molecular arms, which either directly connect to the CND or may penetrate inside the CND. The CND appears to be the convergence of the innermost parts of large-scale gas streamers, which are responding to the central gravitational potential well. Rather than being a quasi-stationary structure, the CND may be dynamically evolving, incorporating inflow via streamers, and feeding gas toward the center.

  18. Hydrodynamics of galaxy mergers with supermassive black holes: is there a last parsec problem?

    NASA Astrophysics Data System (ADS)

    Chapon, Damien; Mayer, Lucio; Teyssier, Romain

    2013-03-01

    We study the formation of a supermassive black hole (SMBH) binary and the shrinking of the separation of the two holes to sub-parsec scales starting from a realistic major merger between two gas-rich spiral galaxies with mass comparable to our Milky Way. The simulations, carried out with the adaptive mesh refinement (AMR) code RAMSES, are capable of resolving separations as small as 0.1 pc. The collision of the two galaxies produces a gravoturbulent rotating nuclear disc with mass (˜109 M⊙) and size (˜60 pc) in excellent agreement with previous smoothed particle hydrodynamics simulations with particle splitting that used a similar set-up (Mayer et al. 2007) but were limited to separations of a few parsecs. The AMR results confirm that the two black holes sink rapidly as a result of dynamical friction on to the gaseous background, reaching a separation of 1 pc in less than 107 yr. We show that the dynamical friction wake is well resolved by our model and we find good agreement with analytical predictions of the drag force as a function of the Mach number. Below 1 pc, black hole pairing slows down significantly, as the relative velocity between the sinking SMBH becomes highly subsonic and the mass contained within their orbit falls below the mass of the binary itself, rendering dynamical friction ineffective. In this final stage, the black holes have not opened a gap as the gaseous background is highly pressurized in the centre. Non-axisymmetric gas torques do not arise to restart sinking in absence of efficient dynamical friction, at variance with previous calculations using idealized equilibrium nuclear disc models. We believe that the rather `hot' equation of state we used to model the multiphase turbulent interstellar medium in the nuclear region is playing an important role in preventing efficient SMBH sinking inside the central parsec. We conclude with a discussion of the way forward to address sinking in gaseous backgrounds at sub-parsec scales approaching

  19. The Role of Cold Gas in Low-level Supermassive Black Hole Activity

    NASA Astrophysics Data System (ADS)

    Alfvin, Erik; Miller, Brendan; Gallo, Elena

    2015-01-01

    The connection between low-level supermassive black hole activity and galactic cold gas, if any, remains debated. It has been hypothesized that mechanical feedback can heat and potentially expel gas and quench star formation; alternatively, central black holes may feed at higher rates in gas-rich galaxies, either directly or as a secondary consequence of greater stellar-wind mass loss. We test this relationship in local spiral galaxies using new HI fluxes from the ongoing ALFALFA 21cm blind survey, in combination with radio data from the literature, and archival X-ray measurements from the Chandra X-ray observatory. We consider late-type galaxies with distances d < 50 Mpc and optical absolute magnitudes MB < -18 as selected from the HyperLeda database. After matching to radio and X-ray coverage and eliminating edge-on galaxies to reduce the complicating effects of internal extinction, our sample consists of 135 spirals. Of these, 75 host a nuclear X-ray source within 2'' of the optical galaxy center, a 56% detection fraction. We estimate the possibility of contamination from high-mass X-ray binaries for each galaxy as a function of the nuclear X-ray luminosity, the star formation rate, and the enclosing projected size of the Chandra point spread function. We perform linear regression (on logarithmic quantities) to fit nuclear X-ray luminosity as a function of galaxy optical luminosity and as a function of HI mass, taking into account measurement uncertainties in both variables and X-ray upper limits. There is a highly significant correlation between Lx and MB, and a tentative correlation (significant at the 2.5 sigma level) between Lx and HI mass. Specifically, we find that log Lx scales with log HI mass with a slope of 0.79+/-0.32, albeit with a large intrinsic scatter of 1.37+/-0.13 dex. These findings suggest that supermassive black holes may indeed accrete at a faster rate in an environment with more cold gas. This work has been supported by NSF grant AST

  20. To test dual supermassive black hole model for broad line active galactic nucleus with double-peaked narrow [O III] lines

    NASA Astrophysics Data System (ADS)

    Zhang, Xue-Guang; Feng, Long-Long

    2016-04-01

    In this paper, we proposed an interesting method to test the dual supermassive black hole model for active galactic nucleus (AGN) with double-peaked narrow [O III] lines (double-peaked narrow emitters) through their broad optical Balmer line properties. Under the dual supermassive black hole model for double-peaked narrow emitters, we could expect statistically smaller virial black hole masses estimated by observed broad Balmer line properties than true black hole masses (total masses of central two black holes). Then, we compare the virial black hole masses between a sample of 37 double-peaked narrow emitters with broad Balmer lines and samples of Sloan Digital Sky Survey selected normal broad line AGN with single-peaked [O III] lines. However, we can find clearly statistically larger calculated virial black hole masses for the 37 broad line AGN with double-peaked [O III] lines than for samples of normal broad line AGN. Therefore, we give our conclusion that the dual supermassive black hole model is probably not statistically preferred to the double-peaked narrow emitters, and more efforts should be necessary to carefully find candidates for dual supermassive black holes by observed double-peaked narrow emission lines.

  1. The Supermassive Black Hole at the Center of the Milky Way

    NASA Astrophysics Data System (ADS)

    Ghez, Andrea M.

    Within the last year two results dramatically strengthened the case for a supermassive black hole at the center of the Milky Way and our understanding the black hole's effect on its environment. First, orbital solutions for multiple stars have been obtained, using adaptive optics and speckle imaging to study the motions of stars in the plane of sky over the past decade. The three most remarkable orbits are those of the newly identified stars S0-16, which passed a mere 60 AU from the central dark mass at a velocity of 9,000 km s-1 in 2000, and S0-19, which at one time was posited to be the near-infrared counterpart to Sgr A*, and the previously recognized S0-2, which has an orbital period of a mere 16 years. A simultaneous orbital analysis yields the most accurate and precise values of the location and mass of the Galaxy's central dark matter. The location is consistent with the inferred infrared position of Sgr A* but with an uncertainty that is a factor of 7 smaller (± 1.5 milliarcsec). The estimated mass from orbital motion is 3.7 (± 0.4) × 106 (R0 8kpc)3 Modot and is a more direct measure of mass than that obtained from velocity dispersion measurements, which are as much as a factor of 2 times smaller; this brings the Milky Way into better agreement with the Mbullet-σ relationship. Furthermore, by confining the mass to within a radius of a mere 0.0003 pc or 1,000 RSch, this orbital analysis increases the inferred dark mass density by four orders of magnitude compared to earlier analyses based on velocity and acceleration vectors, making the Milky Way the strongest existing case for a supermassive black hole at the center of any normal type galaxy. Second, with the introduction of an adaptive-optics-fed spectrometer, the first detection of spectral absorption lines in one of the high-velocity stars, S0-2, was obtained one month after its closest approach to the Galaxy's central supermassive black hole. Both Br γ λ2.1661 microns and He I λ2.1126 microns are

  2. SUPERMASSIVE BLACK HOLES, PSEUDOBULGES, AND THE NARROW-LINE SEYFERT 1 GALAXIES

    SciTech Connect

    Mathur, Smita; Peterson, Bradley M.; Fields, Dale; Grupe, Dirk E-mail: peterson@astronomy.ohio-state.edu E-mail: grupe@astro.psu.edu

    2012-08-01

    We present Hubble Space Telescope Advanced Camera for Surveys (ACS) observations of 10 galaxies that host narrow-line Seyfert 1 (NLS1) nuclei, believed to contain relatively smaller mass black holes accreting at high Eddington ratios. We deconvolve each ACS image into a nuclear point source (AGN), a bulge, and a disk, and fitted the bulge with a Sersic profile and the disk with an exponential profile. We find that at least five galaxies can be classified as having pseudobulges. All 10 galaxies lie below the M{sub BH}-L{sub bulge} relation, confirming earlier results. Their locus is similar to that occupied by pseudobulges. This leads us to conclude that the growth of BHs in NLS1s is governed by secular processes rather than merger driven. Active galaxies in pseudobulges point to an alternative track of black hole-galaxy co-evolution. Because of the intrinsic scatter in black hole mass-bulge properties scaling relations caused by a combination of factors such as the galaxy morphology, orientation, and redshift evolution, application of scaling relations to determine BH masses may not be as straightforward as has been hoped.

  3. Cosmic black-hole hair growth and quasar OJ287

    SciTech Connect

    Horbatsch, M.W.; Burgess, C.P. E-mail: cburgess@perimeterinstitute.ca

    2012-05-01

    An old result (astro-ph/9905303) by Jacobson implies that a black hole with Schwarzschild radius r{sub s} acquires scalar hair, Q∝r{sub s}{sup 2}μ, when the (canonically normalized) scalar field in question is slowly time-dependent far from the black hole, ∂{sub t}φ ≅ μM{sub p} with μr{sub s} << 1 time-independent. Such a time dependence could arise in scalar-tensor theories either from cosmological evolution, or due to the slow motion of the black hole within an asymptotic spatial gradient in the scalar field. Most remarkably, the amount of scalar hair so induced is independent of the strength with which the scalar couples to matter. We argue that Jacobson's Miracle Hair-Growth Formula{sup ©} implies, in particular, that an orbiting pair of black holes can radiate dipole radiation, provided only that the two black holes have different masses. Quasar OJ287, situated at redshift z ≅ 0.306, has been argued to be a double black-hole binary system of this type, whose orbital decay recently has been indirectly measured and found to agree with the predictions of General Relativity to within 6%. We argue that the absence of observable scalar dipole radiation in this system yields the remarkable bound |μ| < (16 days){sup −1} on the instantaneous time derivative at this redshift (as opposed to constraining an average field difference, Δφ, over cosmological times), provided only that the scalar is light enough to be radiated — i.e. m∼<10{sup −23} eV — independent of how the scalar couples to matter. This can also be interpreted as constraining (in a more model-dependent way) the binary's motion relative to any spatial variation of the scalar field within its immediate vicinity within its host galaxy.

  4. Cosmic black-hole hair growth and quasar OJ287

    NASA Astrophysics Data System (ADS)

    Horbatsch, M. W.; Burgess, C. P.

    2012-05-01

    An old result (astro-ph/9905303) by Jacobson implies that a black hole with Schwarzschild radius rs acquires scalar hair, Qproptors2μ, when the (canonically normalized) scalar field in question is slowly time-dependent far from the black hole, ∂tphi simeq μMp with μrs << 1 time-independent. Such a time dependence could arise in scalar-tensor theories either from cosmological evolution, or due to the slow motion of the black hole within an asymptotic spatial gradient in the scalar field. Most remarkably, the amount of scalar hair so induced is independent of the strength with which the scalar couples to matter. We argue that Jacobson's Miracle Hair-Growth Formula© implies, in particular, that an orbiting pair of black holes can radiate dipole radiation, provided only that the two black holes have different masses. Quasar OJ287, situated at redshift z simeq 0.306, has been argued to be a double black-hole binary system of this type, whose orbital decay recently has been indirectly measured and found to agree with the predictions of General Relativity to within 6%. We argue that the absence of observable scalar dipole radiation in this system yields the remarkable bound |μ| < (16 days)-1 on the instantaneous time derivative at this redshift (as opposed to constraining an average field difference, Δphi, over cosmological times), provided only that the scalar is light enough to be radiated — i.e. mlsim10-23 eV — independent of how the scalar couples to matter. This can also be interpreted as constraining (in a more model-dependent way) the binary's motion relative to any spatial variation of the scalar field within its immediate vicinity within its host galaxy.

  5. Black Hole Safari: Tracking Populations and Hunting Big Game

    NASA Astrophysics Data System (ADS)

    McConnell, N. J.

    2013-10-01

    Understanding the physical connection, or lack thereof, between the growth of galaxies and supermassive black holes is a key challenge in extragalactic astronomy. Dynamical studies of nearby galaxies are building a census of black hole masses across a broad range of galaxy types and uncovering statistical correlations between galaxy bulge properties and black hole masses. These local correlations provide a baseline for studying galaxies and black holes at higher redshifts. Recent measurements have probed the extremes of the supermassive black hole population and introduced surprises that challenge simple models of black hole and galaxy co-evolution. Future advances in the quality and quantity of dynamical black hole mass measurements will shed light upon the growth of massive galaxies and black holes in different cosmic environments.

  6. Quasars in the Time Domain: Supermassive Black Hole Binaries and Extreme Objects

    NASA Astrophysics Data System (ADS)

    Graham, Matthew; Djorgovski, Stanislav G.; Stern, Daniel; Drake, Andrew J.; Mahabal, Ashish A.; Glikman, Eilat

    2016-01-01

    Quasar variability can offer insights into the physics of AGN, as it is driven by the variations in the accretion rate, changes in obscuration, and/or instabilities and propagation effects of the relativistic jets. Large synoptic sky surveys such as CRTS (crts.caltech.edu) offer new possibilities in this domain.We use the data set of CRTS light curves of ~335,000 known, spectroscopically confirmed quasars. They have up to a few hundred data points each, with baselines of up to 10 years. This is an unprecedented data set for the studies of quasar variability.We have previously identified a characteristic time scale of stochastic quasar variability, ~54 days (restframe), which anticorrelates with luminosity and black hole mass. While the origin of this phenomenon is not yet understood, it may lead to new insights into the physics of AGN accretion disks and quasars in general. While most quasars show such a characteristic time scale and trends, a subset exhibit a time scale that is significantly different than expected given their physical parameters. We have also found a number of other objects that show extreme variability (in RMS amplitude, or other measures). For a number of these objects we have now detected significant spectroscopic changes that correlate with the photometric variability. We will describe some of the more interesting cases.An even more interesting is the recent detection of periodically variable quasars, which are interpreted as a signature of close (milliparsec scale) supermassive black hole binaries (SMBH) en route to a merger. This population may offer new insights into the assembly of SMBH and their physics in the gravitational wave regime. We have initiate a spectroscopic monitoring program of these objects, and have already detected some spectroscopic changes for some of them. We will describe these results and their possible interpretations.

  7. SEARCH FOR SUPERMASSIVE BLACK HOLE BINARIES IN THE SLOAN DIGITAL SKY SURVEY SPECTROSCOPIC SAMPLE

    SciTech Connect

    Ju, Wenhua; Greene, Jenny E.; Rafikov, Roman R.; Bickerton, Steven J.; Badenes, Carles

    2013-11-01

    Supermassive black hole (SMBH) binaries are expected in a ΛCDM cosmology given that most (if not all) massive galaxies contain a massive black hole (BH) at their center. So far, however, direct evidence for such binaries has been elusive. We use cross-correlation to search for temporal velocity shifts in the Mg II broad emission lines of 0.36 < z < 2 quasars with multiple observations in the Sloan Digital Sky Survey. For ∼10{sup 9} M{sub ☉} BHs in SMBH binaries, we are sensitive to velocity drifts for binary separations of ∼0.1 pc with orbital periods of ∼100 yr. We find seven candidate sub-parsec-scale binaries with velocity shifts >3.4σ ∼ 280 km s{sup –1}, where σ is our systematic error. Comparing the detectability of SMBH binaries with the number of candidates (N ≤ 7), we can rule out that most 10{sup 9} M{sub ☉} BHs exist in ∼0.03-0.2 pc scale binaries, in a scenario where binaries stall at sub-parsec scales for a Hubble time. We further constrain that ≤16% (one-third) of quasars host SMBH binaries after considering gas-assisted sub-parsec evolution of SMBH binaries, although this result is very sensitive to the assumed size of the broad line region. We estimate the detectability of SMBH binaries with ongoing or next-generation surveys (e.g., Baryon Oscillation Spectroscopic Survey, Subaru Prime Focus Spectrograph), taking into account the evolution of the sub-parsec binary in circumbinary gas disks. These future observations will provide longer time baselines for searches similar to ours and may in turn constrain the evolutionary scenarios of SMBH binaries.

  8. The Formation of Galaxies and Supermassive Black Holes: Insights and Puzzles

    NASA Astrophysics Data System (ADS)

    Somerville, Rachel S.

    2014-01-01

    Galaxies exist at a nexus of physical scales, molded by physics ranging from the “small” scales of star formation and accretion onto nuclear black holes, up to the very large scales of the cosmic web. It is this special property that makes galaxies so fascinating and so challenging to study, both observationally and theoretically. The past two decades have seen enormous progress in our understanding of how galaxies form and evolve. We have surveyed slices of the sky at many wavelengths, and built sophisticated models and simulations that attempt to capture the complex array of physics that influences galaxy evolution. We are only now coming into possession of large samples of galaxies for which we can study the internal structure as well as the large scale environment in detail, from the epoch of ‘cosmic high noon’ ( 2) to the present. At the same time, numerical simulations set within a cosmological framework have only recently succeeded in building galaxies with realistic internal structures. It has been known for several years that galaxies are growing in mass and radius, experiencing morphological transformation, and ‘downsizing’ their star formation activity over cosmic time. Now, new observations are painting a picture in which the internal structure of galaxies (size and morphology) is intimately linked with their star formation activity and formation history. There are hints that the co-evolution of supermassive black holes with their host galaxies may be the driving force behind these correlations - but this remains controversial. While cosmological simulations set within the hierarchical formation scenario of Cold Dark Matter currently offer a plausible story for interpreting these observations, many puzzles remain. I will review recent insights gleaned from deep multi-wavelength surveys and state-of-the-art theoretical models and simulations, as well as highlight the open questions and challenges for the future.

  9. Kinematically Identified Recoiling Supermassive Black Hole Candidates in SDSS QSOs with z > 0.25

    NASA Astrophysics Data System (ADS)

    Kim, D.-C.; Evans, A. S.; Stierwalt, S.; Privon, G. C.

    2016-06-01

    We have performed a spectral decomposition to search for recoiling supermassive black holes (rSMBHs) in Sloan Digital Sky Survey (SDSS) quasi-stellar objects (QSOs) with z < 0.25. Out of 1271 QSOs, we have identified 26 rSMBH candidates that are recoiling toward us. The projected recoil velocities range from ‑76 to ‑307 km s‑1 with a mean of ‑149 ± 58 km s‑1. Most of the rSMBH candidates are hosted by gas-rich luminous infrared galaxies (LIRGs)/ultra-luminous infrared galaxies (ULIRGs), but only 23% of them show signs of tidal features, which suggests that a majority of them are advanced mergers. We find that the black hole masses M BH of the rSMBH candidates are on average ∼5 times smaller than those of their stationary counterparts and cause a scatter in the {M}{BH}-{σ }\\ast relation. The Eddington ratios of all of the rSMBH candidates are larger than 0.1, with a mean of 0.52 ± 0.27, suggesting that they are actively accreting mass. Velocity shifts in high-excitation coronal lines suggest that the rSMBH candidates are recoiling with an average velocity of about ‑265 km s‑1. The electron density in the narrow line region of the H ii rSMBH candidates is about 1/10 of that in active galactic nucleus (AGN) rSMBH candidates, probably because the AGN in the former was more spatially offset than that in the latter. The estimated spatial offsets between the rSMBH candidate and the center of the host galaxy range from 0.″21 to 1.″97 and need to be confirmed spatially with high-resolution adaptive optics imaging observations.

  10. RESOLVING THE BONDI ACCRETION FLOW TOWARD THE SUPERMASSIVE BLACK HOLE OF NGC 3115 WITH CHANDRA

    SciTech Connect

    Wong, Ka-Wah; Irwin, Jimmy A.; Yukita, Mihoko; Million, Evan T.; Mathews, William G.

    2011-07-20

    Gas undergoing Bondi accretion onto a supermassive black hole (SMBH) becomes hotter toward smaller radii. We searched for this signature with a Chandra observation of the hot gas in NGC 3115, which optical observations show has a very massive SMBH. Our analysis suggests that we are resolving, for the first time, the accretion flow within the Bondi radius of an SMBH. We show that the temperature is rising toward the galaxy center as expected in all accretion models in which the black hole is gravitationally capturing the ambient gas. There is no hard central point source that could cause such an apparent rise in temperature. The data support that the Bondi radius is at about 4''-5'' (188-235 pc), suggesting an SMBH of 2 x 10{sup 9} M{sub sun} that is consistent with the upper end of the optical results. The density profile within the Bondi radius has a power-law index of 1.03{sup +0.23}{sub -0.21}, which is consistent with gas in transition from the ambient medium and the accretion flow. The accretion rate at the Bondi radius is determined to be M-dot{sub B} = 2.2x10{sup -2} M{sub sun} yr{sup -1}. Thus, the accretion luminosity with 10% radiative efficiency at the Bondi radius (10{sup 44} erg s{sup -1}) is about six orders of magnitude higher than the upper limit of the X-ray luminosity of the nucleus.

  11. 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

  12. Evidence for a Super-massive Black Hole at the Center of the Milky Way

    NASA Astrophysics Data System (ADS)

    Reid, Mark

    2012-03-01

    While the concept of a black hole formed by the explosive collapse of a dying star is astounding, the possibility that matter from billions of stars can condense into a single super-massive black hole (SMBH) is even more fantastic. Yet astronomers are now confident that they exist at the centers of most galaxies and hold more than 0.01% of the baryonic mass of the Universe. Early evidence for SMBHs came from ``radio galaxies'' with two lobes symmetrically placed about the parent galaxy. These lobes are immense and minimum energy estimates require the total conversion of 10^7 stars to energy! The source of energy was traced to galaxy's center and observed to vary on time scales <1 year. Since nuclear reactions convert less than 1% of mass to energy, this would require channeling >10^9 stars through a region smaller than that between the Sun and the nearest star. A very compact radio source was discovered toward the center of the Milky Way and named Sgr A*, leading to speculation that it might be a SMBH. Infrared observations of stars on elliptical orbits give clear evidence of an unseen gravitational source of 4x10^6 solar masses. One star has been seen moving at 5000 km/s in its 16 year eccentric orbit. Sgr A* has been located at the position of the gravitational focus of the stellar orbits. However, in contrast to the rapidly moving stars, Sgr A* is motionless (<1 km/s), requiring the source to be extremely massive. For comparison, gravitational ``Brownian motion'' of a SMBH at the center of a dense stellar cluster would be comparable to the measured limits. Recent radio interferometric observations show that the radio emission from Sgr A* comes from a region comparable in size to the Schwarzschild radius (2GM/c^2) of 0.1 AU (1.5x10^7 km)! Placing any known concentration of 4x10^6 solar masses within this tiny volume would rapidly condense to a black hole.

  13. Enhanced Accretion Rates of Stars on Supermassive Black Holes by Star-Disk Interactions in Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Just, Andreas; Yurin, Denis; Makukov, Maxim; Berczik, Peter; Omarov, Chingis; Spurzem, Rainer; Vilkoviskij, Emmanuil Y.

    2012-10-01

    We investigate the dynamical interaction of a central star cluster surrounding a supermassive black hole (SMBH) and a central accretion disk (AD). The dissipative force acting on stars in the disk leads to an enhanced mass flow toward the SMBH and to an asymmetry in the phase space distribution due to the rotating AD. The AD is considered as a stationary Keplerian rotating disk, which is vertically extended in order to employ a fully self-consistent treatment of stellar dynamics including the dissipative force originating from star-gas ram pressure effects. The stellar system is treated with a direct high-accuracy N-body integration code. A star-by-star representation, desirable in N-body simulations, cannot be extended to real particle numbers yet. Hence, we carefully discuss the scaling behavior of our model with regard to particle number and tidal accretion radius. The main idea is to find a family of models for which the ratio of two-body relaxation time and dissipation time (for kinetic energy of stellar orbits) is constant, which then allows us to extrapolate our results to real parameters of galactic nuclei. Our model is derived from basic physical principles and as such it provides insight into the role of physical processes in galactic nuclei, but it should be regarded as a first step toward more realistic and more comprehensive simulations. Nevertheless, the following conclusions appear to be robust: the star accretion rate onto the AD and subsequently onto the SMBH is enhanced by a significant factor compared to purely stellar dynamical systems neglecting the disk. This process leads to enhanced fueling of central disks in active galactic nuclei (AGNs) and to an enhanced rate of tidal stellar disruptions. Such disruptions may produce electromagnetic counterparts in the form of observable X-ray flares. Our models improve predictions for their rates in quiescent galactic nuclei. We do not yet model direct stellar collisions in the gravitational potential

  14. ENHANCED ACCRETION RATES OF STARS ON SUPERMASSIVE BLACK HOLES BY STAR-DISK INTERACTIONS IN GALACTIC NUCLEI

    SciTech Connect

    Just, Andreas; Yurin, Denis; Makukov, Maxim; Berczik, Peter; Omarov, Chingis; Spurzem, Rainer; Vilkoviskij, Emmanuil Y.

    2012-10-10

    We investigate the dynamical interaction of a central star cluster surrounding a supermassive black hole (SMBH) and a central accretion disk (AD). The dissipative force acting on stars in the disk leads to an enhanced mass flow toward the SMBH and to an asymmetry in the phase space distribution due to the rotating AD. The AD is considered as a stationary Keplerian rotating disk, which is vertically extended in order to employ a fully self-consistent treatment of stellar dynamics including the dissipative force originating from star-gas ram pressure effects. The stellar system is treated with a direct high-accuracy N-body integration code. A star-by-star representation, desirable in N-body simulations, cannot be extended to real particle numbers yet. Hence, we carefully discuss the scaling behavior of our model with regard to particle number and tidal accretion radius. The main idea is to find a family of models for which the ratio of two-body relaxation time and dissipation time (for kinetic energy of stellar orbits) is constant, which then allows us to extrapolate our results to real parameters of galactic nuclei. Our model is derived from basic physical principles and as such it provides insight into the role of physical processes in galactic nuclei, but it should be regarded as a first step toward more realistic and more comprehensive simulations. Nevertheless, the following conclusions appear to be robust: the star accretion rate onto the AD and subsequently onto the SMBH is enhanced by a significant factor compared to purely stellar dynamical systems neglecting the disk. This process leads to enhanced fueling of central disks in active galactic nuclei (AGNs) and to an enhanced rate of tidal stellar disruptions. Such disruptions may produce electromagnetic counterparts in the form of observable X-ray flares. Our models improve predictions for their rates in quiescent galactic nuclei. We do not yet model direct stellar collisions in the gravitational potential

  15. Intermediate mass black holes in AGN discs - I. Production and growth

    NASA Astrophysics Data System (ADS)

    McKernan, B.; Ford, K. E. S.; Lyra, W.; Perets, H. B.

    2012-09-01

    Here we propose a mechanism for efficiently growing intermediate mass black holes (IMBH) in discs around supermassive black holes. Stellar mass objects can efficiently agglomerate when facilitated by the gas disc. Stars, compact objects and binaries can migrate, accrete and merge within discs around supermassive black holes. While dynamical heating by cusp stars excites the velocity dispersion of nuclear cluster objects (NCOs) in the disc, gas in the disc damps NCO orbits. If gas damping dominates, NCOs remain in the disc with circularized orbits and large collision cross-sections. IMBH seeds can grow extremely rapidly by collisions with disc NCOs at low relative velocities, allowing for super-Eddington growth rates. Once an IMBH seed has cleared out its feeding zone of disc NCOs, growth of IMBH seeds can become dominated by gas accretion from the active galactic nucleus (AGN) disc. However, the IMBH can migrate in the disc and expand its feeding zone, permitting a super-Eddington accretion rate to continue. Growth of IMBH seeds via NCO collisions is enhanced by a pile-up of migrators. We highlight the remarkable parallel between the growth of IMBH in AGN discs with models of giant planet growth in protoplanetary discs. If an IMBH becomes massive enough it can open a gap in the AGN disc. IMBH migration in AGN discs may stall, allowing them to survive the end of the AGN phase and remain in galactic nuclei. Our proposed mechanisms should be more efficient at growing IMBH in AGN discs than the standard model of IMBH growth in stellar clusters. Dynamical heating of disc NCOs by cusp stars is transferred to the gas in an AGN disc helping to maintain the outer disc against gravitational instability. Model predictions, observational constraints and implications are discussed in a companion paper (Paper II).

  16. Supermassive black hole formation by cold accretion shocks in the first galaxies

    NASA Astrophysics Data System (ADS)

    Inayoshi, Kohei; Omukai, Kazuyuki

    2012-05-01

    We propose a new scenario for supermassive star (SMS: >rsim 105 M⊙) formation in shocked regions of colliding cold accretion flows near the centres of the first galaxies. Recent numerical simulations indicate that assembly of a typical first galaxy with virial temperature Tvir≳104 K proceeds via cold and dense flows penetrating deep to the centre, where supersonic streams collide with each other to develop a hot (˜104 K) and dense (˜103 cm-3) shocked gas. The post-shock layer first cools by efficient Lyα emission and contracts isobarically until ≃8000 K. Whether the layer continues its isobaric contraction depends on the density at this moment: if the density is high enough to excite H2 rovibrational levels collisionally (>rsim 104 cm-3), enhanced H2 collisional dissociation suppresses the gas from cooling further. In this case, the layer fragments into massive (>rsim 105 M⊙) clouds, which collapse isothermally (˜8000 K) by Lyα cooling without subsequent fragmentation. As an outcome, SMSs are expected to form and eventually evolve into the seeds of supermassive black holes (SMBHs). By calculating the thermal evolution of the post-shock gas, we delimit the range of post-shock conditions for SMS formation, which can be expressed as T≳6000 K (nH/104 cm-3)-1 for ? and T>rsim 5000 -6000 K for nH≳104 cm-3, depending somewhat on the initial ionization degree. We found that metal enrichment does not affect the above condition for metallicity below ≃10-3 Z⊙ if metals are in the gas phase, while condensation of several per cent of metals into dust decreases this critical value of metallicity by an order of magnitude. Unlike the previously proposed scenario for SMS formation, which postulates extremely strong ultraviolet radiation to quench H2 cooling, our scenario here naturally explains SMBH seed formation in the assembly process of the first galaxies, even without such strong radiation.

  17. Rapid growth of seed black holes in the early universe by supra-exponential accretion.

    PubMed

    Alexander, Tal; Natarajan, Priyamvada

    2014-09-12

    Mass accretion by black holes (BHs) is typically capped at the Eddington rate, when radiation's push balances gravity's pull. However, even exponential growth at the Eddington-limited e-folding time t(E) ~ few × 0.01 billion years is too slow to grow stellar-mass BH seeds into the supermassive luminous quasars that are observed when the universe is 1 billion years old. We propose a dynamical mechanism that can trigger supra-exponential accretion in the early universe, when a BH seed is bound in a star cluster fed by the ubiquitous dense cold gas flows. The high gas opacity traps the accretion radiation, while the low-mass BH's random motions suppress the formation of a slowly draining accretion disk. Supra-exponential growth can thus explain the puzzling emergence of supermassive BHs that power luminous quasars so soon after the Big Bang. PMID:25103410

  18. Rapid growth of seed black holes in the early universe by supra-exponential accretion

    NASA Astrophysics Data System (ADS)

    Alexander, Tal; Natarajan, Priyamvada

    2014-09-01

    Mass accretion by black holes (BHs) is typically capped at the Eddington rate, when radiation's push balances gravity's pull. However, even exponential growth at the Eddington-limited e-folding time tE ~ few × 0.01 billion years is too slow to grow stellar-mass BH seeds into the supermassive luminous quasars that are observed when the universe is 1 billion years old. We propose a dynamical mechanism that can trigger supra-exponential accretion in the early universe, when a BH seed is bound in a star cluster fed by the ubiquitous dense cold gas flows. The high gas opacity traps the accretion radiation, while the low-mass BH's random motions suppress the formation of a slowly draining accretion disk. Supra-exponential growth can thus explain the puzzling emergence of supermassive BHs that power luminous quasars so soon after the Big Bang.

  19. XMM-Newton reveals matter accreting onto the central supermassive black hole of NGC 2617

    NASA Astrophysics Data System (ADS)

    Giustini, M.

    2016-06-01

    NGC 2617 (z=0.042) underwent a strong broad-band outburst during 2013/14, concurrently switching from being a Seyfert 1.8 to be a Seyfert 1.0 sometimes during the previous 10 years. Thanks to the combination of the large effective area and the good spectral resolution of the EPIC-pn onboard XMM-Newton, striking insights about the very inner accretion flow of this AGN have been revealed. In particular, persistent Fe K absorption redshifted by ˜ 35,000 km/s was solidly detected in two observations spaced by one month: a highly ionised flow of mass toward the central supermassive black hole of NGC 2617 has started to be traced. So far NGC 2617 is a quasi-unique observational example: what are the perspectives of enlarging these studies in the future? Thanks to current large and prolonged optical surveys like the SDSS/BOSS, many "optically changing-look AGN" like NGC 2617 are being discovered month after month: XMM-Newton has the ideal instruments to perform a proper X-ray study of such objects in the near future. I will assess the impact of XMM-Newton on studying the dynamics of the inner accretion flow in AGN in a systematic way and in synergy with near- and mid-future X-ray instruments such as (ASTRO-H)Hitomi and ATHENA.

  20. Supermassive Black Holes, AGN Feedback, and Hot X-ray Coronae in Early Type Galaxies

    NASA Astrophysics Data System (ADS)

    Forman, William R.; Anderson, Michael E.; Churazov, Eugene; Nulsen, Paul; Jones, Christine; Kraft, Ralph P.

    2016-06-01

    We present the analysis of a sample of more than 200 nearby, early type galaxies observed with the Chandra X-ray Observatory. We exclude resolved point sources, and model the emission from both unresolved X-ray binaries and CVs and ABs to derive the residual thermal emission from the hot atmosphere around each galaxy. We compute the X-ray luminosity of the central supermassive black hole (SMBH). Using galaxy velocity dispersion (or stellar mass) as a proxy for SMBH mass, we derive the Eddington ratios for these low luminosity AGN. We present the X-ray luminosity and gas temperature of the hot coronae as a function of stellar mass (a proxy for dark matter halo mass) and central velocity dispersion to look for anomalously X-ray bright gaseous coronae and to determine the stellar (or halo) mass, below which galactic winds may be important. For hot coronae with X-ray cavities, we derive the "mechanical" power of SMBHs and compare these to their radiative luminosities.

  1. An estimate of the probability of capture of a binary star by a supermassive black hole

    NASA Astrophysics Data System (ADS)

    Dremova, G. N.; Dremov, V. V.; Tutukov, A. V.

    2016-08-01

    A simple model for the dynamics of stars located in a sphere with a radius of one-tenth of the central parsec, designed to enable estimation of the probability of capture in the close vicinity ( r < 10-3 pc) of a supermassive black hole (SMBH) is presented. In the case of binary stars, such a capture with a high probability results in the formation of a hyper-velocity star. The population of stars in a sphere of radius <0.1 pc is calculated based on data for the Galactic rotation curve. To simulate the distortion of initially circular orbits of stars, these are subjected to a series of random shock encounters ("kicks"), whose net effect is to "push" these binary systems into the region of potential formation of hyper-velocity stars. The mean crossing time of the border of the close vicinity of the SMBH ( r < 10-3 pc) by the stellar orbit can be used to estimate the probability that a binary system is captured, followed by the possible ejection of a hyper-velocity star.

  2. SPECTROPOLARIMETRIC EVIDENCE FOR A KICKED SUPERMASSIVE BLACK HOLE IN THE QUASAR E1821+643

    SciTech Connect

    Robinson, Andrew; Young, Stuart; Axon, David J.; Kharb, Preeti; Smith, James E.

    2010-07-10

    We report spectropolarimetric observations of the quasar E1821+643 (z = 0.297), which suggest that it may be an example of gravitational recoil due to anisotropic emission of gravitational waves following the merger of a supermassive black hole (SMBH) binary. In total flux, the broad Balmer lines are redshifted by {approx}1000 km s{sup -1} relative to the narrow lines and have highly red asymmetric profiles, whereas in polarized flux the broad H{alpha} line exhibits a blueshift of similar magnitude and a strong blue asymmetry. We show that these observations are consistent with a scattering model in which the broad-line region has two components, moving with different bulk velocities away from the observer and toward a scattering region at rest in the host galaxy. If the high-velocity system is identified as gas bound to the SMBH, this implies that the SMBH is itself moving with a velocity {approx}2100 km s{sup -1} relative to the host galaxy. We discuss some implications of the recoil hypothesis and also briefly consider whether our observations can be explained in terms of scattering of broad-line emission originating from the active component of an SMBH binary, or from an outflowing wind.

  3. Inward Bound---The Search For Supermassive Black Holes In Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Kormendy, John; Richstone, Douglas

    Dynamical searches reveal central dark objects with masses $\\sim 10^6$to $10^{9.5}$ \\msun in the Galaxy, \\m31, \\mm32, M87, NGC 3115, NGC 3377, NGC 4258, and NGC 4594. Indirect arguments suggest but do not prove that these are supermassive black holes (BHs) like those postulated as quasar engines. This paper reviews dynamical search techniques, the robustness of the evidence, and BH demographics. Stellar-dynamical evidence is generally more robust than gas-dynamical evidence (gas velocities can be nongravitational), but gas measurements reach closer to the Schwarzschild radius, and in NGC 4258 they show a Keplerian rotation curve. A statistical survey finds BHs in $\\sim 20\\%$ of nearby E--Sbc galaxies, consistent with predictions based on quasar energetics. BH masses are proportional to the mass of the bulge component. Most candidates are inactive; in some cases, the abundance of fuel is not easily reconciled with BH starvation. Flashes caused by the accretion of individual stars may provide a test of the BH picture.

  4. Gravitational Wave Driven Mergers and Coalescence Time of Supermassive Black Holes

    NASA Astrophysics Data System (ADS)

    Khan, Fazeel Mahmood; Berczik, Peter; Just, Andreas

    2016-07-01

    The evolution of Supermassive Black Holes (SMBHs) initially embedded in the centers of merging galaxies is studied from the onset of galaxy mergers till coalescence. We performed direct N-body simulations using the highly efficient and massively parallel phi-GPU code capable to run on GPU supported high performance computer clusters. Post-Newtonian terms up to order 3.5 are used to drive the SMBH binary evolution in the relativistic regime. We find that SMBH binaries coalesce well within one billion year when our models are scaled to dense cuspy galaxies at low redshift. Here higher central densities provide larger supply of stars to efficiently extract energy from the SMBH binary orbit and shrink it to the phase where gravitational wave (GW) emission becomes dominant leading to the coalescence of the SMBHs. On the other hand, mergers of models that are representative of giant elliptical galaxies having central cores result in less efficient extraction of binary's orbit energy due to the lower stellar densities in the center. However, high value of eccentricities witnessed for SMBH binaries in such galaxy mergers ensure that the GW emission dominated phase sets in at larger values of the semi-major axis. This helps to compensate for the less efficient energy extraction during the phase dominated by stellar encounters resulting in mergers of SMBHs in about one billion years after the formation of binary.

  5. Effects of High-energy Particles on Accretion Flows onto a Supermassive Black Hole

    NASA Astrophysics Data System (ADS)

    Kimura, Shigeo S.; Toma, Kenji; Takahara, Fumio

    2014-08-01

    We study the effects of high-energy particles (HEPs) on the accretion flows onto a supermassive black hole and luminosities of escaping particles such as protons, neutrons, gamma rays, and neutrinos. We formulate a one-dimensional model of the two-component accretion flow consisting of thermal particles and HEPs, supposing that some fraction of the released energy is converted to the acceleration of HEPs. The thermal component is governed by fluid dynamics while the HEPs obey the moment equations of the diffusion-convection equation. By solving the time evolution of these equations, we obtain advection-dominated flows as the steady state solutions. The effects of the HEPs on the flow structures turn out to be small even if the pressure of the HEPs dominates over the thermal pressure. For a model in which the escaping protons take away almost all the energy released, the HEPs have a large enough influence to make the flow have a Keplerian angular velocity at the inner region. We calculate the luminosities of the escaping particles for these steady solutions. The escaping particles can extract the energy from about 10^{-4}\\dot{M} c^2 to 10^{-2}\\dot{M} c^2, where \\dot{M} is the mass accretion rate. The luminosities of the escaping particles depend on parameters such as the injection Lorentz factors, the mass accretion rates, and the diffusion coefficients. We also discuss some implications on the relativistic jet production by the escaping particles.

  6. Can Supermassive Black Holes Influence the Evolution of their Host Galaxies?

    NASA Astrophysics Data System (ADS)

    Tombesi, Francesco; Veilleux, Sylvain; Reeves, James; Reynolds, Christopher S.

    2016-04-01

    Powerful winds driven by active galactic nuclei (AGN) are often invoked to play a fundamental role in the evolution of both supermassive black holes (SMBHs) and their host galaxies, quenching star formation and explaining the tight SMBH-galaxy relations. A strong support of this "quasar-mode" feedback came from the recent X-ray observation of a mildly relativistic accretion disk wind in the ultraluminous infrared galaxy IRAS F11119+3257 hosting a luminous quasar at the center. Energetics arguments indicate a connection with a massive, large-scale molecular outflow observed in infrared with Herschel. This seems to be in agreement with theoretical models in which AGN winds drive hot bubbles in the host galaxy medium, thereby providing a link between the SMBH and the gas out of which stars form. This work was the “cover story” of the March 26th 2015 issue of Nature. Revolutionary improvements in this field are expected from ASTRO-H and Athena.

  7. VERY HIGH ENERGY {gamma}-RAY EMISSION FROM PASSIVE SUPERMASSIVE BLACK HOLES: CONSTRAINTS FOR NGC 1399

    SciTech Connect

    Pedaletti, G.; Wagner, S. J.; Rieger, F. M.

    2011-09-10

    Very high energy (VHE, >100 GeV) {gamma}-rays are expected to be emitted from the vicinity of supermassive black holes (SMBHs), irrespective of their activity state. In the magnetosphere of rotating SMBH, efficient acceleration of charged particles can take place through various processes. These particles could reach energies up to E {approx} 10{sup 19} eV. VHE {gamma}-ray emission from these particles is then feasible via leptonic or hadronic processes. Therefore, passive systems, where the lack of a strong photon field allows the VHE {gamma}-rays to escape, are expected to be detected by Cherenkov telescopes. We present results from recent VHE experiments on the passive SMBH in the nearby elliptical galaxy NGC 1399. No {gamma}-ray signal has been found, neither by the H.E.S.S. experiment nor in the Fermi data analyzed here. We discuss possible implications for the physical characteristics of the system. We conclude that in a scenario where particles are accelerated in vacuum gaps in the magnetosphere, only a fraction {approx}0.3 of the gap is available for particle acceleration, indicating that the system is unlikely to be able to accelerate protons up to E {approx} 10{sup 19} eV.

  8. A Hamiltonian Monte-Carlo method for Bayesian inference of supermassive black hole binaries

    NASA Astrophysics Data System (ADS)

    Porter, Edward K.; Carré, Jérôme

    2014-07-01

    We investigate the use of a Hamiltonian Monte-Carlo to map out the posterior density function for supermassive black hole binaries. While previous Markov Chain Monte-Carlo (MCMC) methods, such as Metropolis-Hastings MCMC, have been successfully employed for a number of different gravitational wave sources, these methods are essentially random walk algorithms. The Hamiltonian Monte-Carlo treats the inverse likelihood surface as a ‘gravitational potential’ and by introducing canonical positions and momenta, dynamically evolves the Markov chain by solving Hamilton's equations of motion. This method is not as widely used as other MCMC algorithms due to the necessity of calculating gradients of the log-likelihood, which for most applications results in a bottleneck that makes the algorithm computationally prohibitive. We circumvent this problem by using accepted initial phase-space trajectory points to analytically fit for each of the individual gradients. Eliminating the waveform generation needed for the numerical derivatives reduces the total number of required templates for a {{10}^{6}} iteration chain from \\sim {{10}^{9}} to \\sim {{10}^{6}}. The result is in an implementation of the Hamiltonian Monte-Carlo that is faster, and more efficient by a factor of approximately the dimension of the parameter space, than a Hessian MCMC.

  9. Infalling clouds on to supermassive black hole binaries - I. Formation of discs, accretion and gas dynamics

    NASA Astrophysics Data System (ADS)

    Goicovic, F. G.; Cuadra, J.; Sesana, A.; Stasyszyn, F.; Amaro-Seoane, P.; Tanaka, T. L.

    2016-01-01

    There is compelling evidence that most - if not all - galaxies harbour a supermassive black hole (SMBH) at their nucleus; hence binaries of these massive objects are an inevitable product of the hierarchical evolution of structures in the Universe, and represent an important but thus-far elusive phase of galaxy evolution. Gas accretion via a circumbinary disc is thought to be important for the dynamical evolution of SMBH binaries, as well as in producing luminous emission that can be used to infer their properties. One plausible source of the gaseous fuel is clumps of gas formed due to turbulence and gravitational instabilities in the interstellar medium, that later fall towards and interact with the binary. In this context, we model numerically the evolution of turbulent clouds in near-radial infall on to equal-mass SMBH binaries, using a modified version of the SPH (smoothed particle hydrodynamics) code GADGET-3. We present a total of 12 simulations that explore different possible pericentre distances and relative inclinations, and show that the formation of circumbinary discs and discs around each SMBH (`mini-discs') depend on those parameters. We also study the dynamics of the formed discs, and the variability of the feeding rate on to the SMBHs in the different configurations.

  10. A possible close supermassive black-hole binary in a quasar with optical periodicity.

    PubMed

    Graham, Matthew J; Djorgovski, S G; Stern, Daniel; Glikman, Eilat; Drake, Andrew J; Mahabal, Ashish A; Donalek, Ciro; Larson, Steve; Christensen, Eric

    2015-02-01

    Quasars have long been known to be variable sources at all wavelengths. Their optical variability is stochastic and can be due to a variety of physical mechanisms; it is also well-described statistically in terms of a damped random walk model. The recent availability of large collections of astronomical time series of flux measurements (light curves) offers new data sets for a systematic exploration of quasar variability. Here we report the detection of a strong, smooth periodic signal in the optical variability of the quasar PG 1302-102 with a mean observed period of 1,884 ± 88 days. It was identified in a search for periodic variability in a data set of light curves for 247,000 known, spectroscopically confirmed quasars with a temporal baseline of about 9 years. Although the interpretation of this phenomenon is still uncertain, the most plausible mechanisms involve a binary system of two supermassive black holes with a subparsec separation. Such systems are an expected consequence of galaxy mergers and can provide important constraints on models of galaxy formation and evolution. PMID:25561176