Black Holes In Nearby Galaxies Research Articles

The High Energy X-ray Probe (HEX-P): probing accretion onto stellar mass black holes

Accretion is a universal astrophysical process that plays a key role in cosmic history, from the epoch of reionization to galaxy and stellar formation and evolution. Accreting stellar-mass black holes in X-ray binaries are one of the best laboratories to study the accretion process and probe strong gravity—and most importantly, to measure the angular momentum, or spin, of black holes, and its role as a powering mechanism for relativistic astrophysical phenomena. Comprehensive characterization of the disk-corona system of accreting black holes, and their co-evolution, is fundamental to measurements of black hole spin. Here, we use simulated data to demonstrate how key unanswered questions in the study of accreting stellar-mass black holes will be addressed by the High Energy X-ray Probe (HEX-P). HEX-P is a probe-class mission concept that will combine high spatial resolution X-ray imaging and broad spectral coverage (0.2–80 keV) with a sensitivity superior to current facilities (including XMM-Newton and NuSTAR) to enable revolutionary new insights into a variety of important astrophysical problems. We illustrate the capability of HEX-P to: 1) measure the evolving structures of black hole binary accretion flows down to low (≲ 0.1%) Eddington-scaled luminosities via detailed X-ray reflection spectroscopy; 2) provide unprecedented spectral observations of the coronal plasma, probing its elusive geometry and energetics; 3) perform detailed broadband studies of stellar mass black holes in nearby galaxies, thus expanding the repertoire of sources we can use to study accretion physics and determine the fundamental nature of black holes; and 4) act as a complementary observatory to a range of future ground and space-based astronomical observatories, thus providing key spectral measurements of the multi-component emission from the inner accretion flows of black hole X-ray binaries.

The Host Galaxy of OJ 287 Revealed by Optical and Near-infrared Imaging

Abstract The BL Lacertae object OJ 287 (z = 0.306) has unique double-peaked optical outbursts every ∼12 yr, and it presents one of the best cases for a small-separation binary supermassive black hole (SMBH) system, with an extremely massive primary . However, the host galaxy is unresolved or only marginally detected in all optical studies so far, indicating a large deviation from the bulge mass—SMBH mass relation. We have obtained deep, high spatial resolution i-band and K-band images of OJ 287 when the target was in a low state, which enable us to detect the host galaxy. We find the broadband photometry of the host to be consistent with an early-type galaxy with M R = −22.5 and M K = −25.2, placing it in the middle of the host galaxy luminosity distribution of BL Lacertae objects. The central supermassive black hole is clearly overmassive for a host galaxy of that luminosity, but not unprecedented, given some recent findings of other “overmassive” black holes in nearby galaxies.

Introducing the Search for Intermediate-mass Black Holes in Nearby Galaxies (SIBLING) Survey

Abstract Intermediate-mass black holes (IMBHs) have masses between 102 and 106 M ⊙ and are key to our understanding of the formation of massive black holes. The known population of IMBHs remains small, with a few hundred candidates and only a handful of them confirmed as bona fide IMBHs. Until now, the most widely used selection method is based on spectral analysis. Here we present a methodology to select IMBH candidates via optical variability analysis of the nuclear region of local galaxies ( ). Active IMBHs accreting at low rates show small amplitude variability with timescales of hours, as is seen in one of the known IMBHs, NGC 4395. We found a sample of ∼500 galaxies demonstrating fast and small amplitude variation in their week-based light curves. We estimate an average occupancy fraction of 4% and a surface density of ∼3 deg−2, which represent an increase by a factor of ∼40 compared to previous searches. A large fraction (78%) of the candidates are in spiral galaxies. We preliminarily confirm the active galactic nucleus nature of 22 sources via Baldwin, Phillips, and Terlevich diagrams using Sloan Digital Sky Survey legacy spectra. Further confirmation of these candidates will require multiwavelength observations, especially in X-ray and radio bands.

The birth of an AGN: NGC 4111

AbstractWe have used near-infrared and optical Integral Field Spectroscopy along with optical images to study the inner 100 pc of NGC 4111 in a project to investigate the stellar and gas kinematics in the surroundings of Supermassive Black Holes in nearby galaxies. We have compared the inner stellar and gas kinematics with data of the outer regions of the galaxy. We found larger scale hot ionized gas and warm molecular gas within the inner 100 pc that is in counter-rotation relative to the stellar kinematics, a sign of inflowing material that is probably triggering an Active Galactic Nucleus. This is supported by the nuclear X-ray emission which is heating the molecular gas and causing it to emit. The presence of large amounts of dust in a polar ring suggests that this is a fairly recent event probably due to the capture of a dwarf galaxy.

Story one: Giant black holes in nearby galaxies may be more massive than thought: Simulations, observations may resolve long‐standing puzzle

Science NewsVolume 176, Issue 1 p. 5-6 In The News Story one: Giant black holes in nearby galaxies may be more massive than thought: Simulations, observations may resolve long-standing puzzle Ron Cowen, Ron CowenSearch for more papers by this author Ron Cowen, Ron CowenSearch for more papers by this author First published: 09 October 2009 https://doi.org/10.1002/scin.5591760104AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume176, Issue14 July 2009Pages 5-6 RelatedInformation

On the Black Hole Mass-Bulge Mass Relation

We have re-examined the relation between the mass of the central black holes in nearby galaxies, M_bh, and the stellar mass of the surrounding spheroid or bulge, M_bulge. For a total of 30 galaxies bulge masses were derived through Jeans equation modeling or adopted from dynamical models in the literature. In stellar mass-to-light ratios the spheroids and bulges span a range of a factor of eight. The bulge masses were related to well-determined black hole masses taken from the literature. With these improved values for M_bh, compared to Magorrian et al. (1998), and our redetermination of M_bulge, we find the M_bh-M_bulge relation becomes very tight. We find M_bh ~ M_bulge^(1.12+/-0.06) with an observed scatter of < 0.30 dex, a fraction of which can be attributed to measurement errors. The scatter in this relation is therefore comparable to the scatter in the relations of M_bh with sigma and the stellar concentration. These results confirm and refine the work of Marconi and Hunt (2003). For M_bulge~5x10^10 M_sun the median black hole mass is 0.14% +/- 0.04% of the bulge mass.

Constraints on QSO Models from a Relation between the QSO Luminosity Function and the Local Black Hole Mass Function

QSOs are believed to be powered by accretion onto massive black holes (BHs). In this paper, assuming that each central BH in nearby galaxies has experienced the QSO phase and ignoring BH mergers, we establish a relation between the QSO luminosity function (LF) and the local BH mass function (MF). The QSOLF is jointly controlled by the luminosity evolution of individual QSOs and the triggering history of the accretion onto seed BHs. By comparing the time integral of the QSOLF with that inferred from local BHs, we separate the effect of the luminosity evolution of individual QSOs from the effect of the triggering history. Assuming that the nuclear luminosity evolution includes two phases (first increasing at the Eddington luminosity with growth of BHs and then declining), we find that observations are generally consistent with the expected relation between the QSOLF and the local BHMF and obtain the following constraints on QSO models and BH growth: (i) The QSO mass-to-energy efficiency should be ≳0.1. (ii) The lifetime (defined directly through the luminosity evolution of individual QSOs here) should be ≳4 × 107 yr. The characteristic declining timescale in the second phase should be significantly shorter than the Salpeter timescale τSp, and BH growth should not be dominated by the second phase. (iii) The ratio of obscured QSOs/AGNs to optically bright QSOs should be not larger than 7 at MB ~ -23 and 3 at MB ~ -26 if = 0.31, and not larger than 1 at MB ~ -23 and negligible at MB ~ -26 if = 0.1. (iv) It is unlikely that most QSOs are accreting at super-Eddington luminosities. We point out that it is hard to accurately estimate the value of the QSO lifetime from the QSOLF and/or the local BHMF, if it is longer than a certain value (e.g., ~4τSp in this study). We discuss the importance of accurate measurements of the intrinsic scatter in the BH mass and velocity dispersion relation of local galaxies and the scatter in the bolometric correction of QSOs. We also discuss some possible applications of the work in this paper, such as to the study of the demography of QSOs and the demography of normal galaxies at intermediate redshift.

Bondi Accretion and the Problem of the Missing Isolated Neutron Stars

A large number of neutron stars (NSs), approximately 10(exp 9), populate the Galaxy, but only a tiny fraction of them is observable during the short radio pulsar lifetime. The majority of these isolated NSs, too cold to be detectable by their own thermal emission, should be visible in X-rays as a result of accretion from the interstellar medium. The ROSAT All-Sky Survey has, however, shown that such accreting isolated NSs are very elusive: only a few tentative candidates have been identified, contrary to theoretical predictions that up to several thousand should be seen. We suggest that the fundamental reason for this discrepancy lies in the use of the standard Bondi formula to estimate the accretion rates. We compute the expected source counts using updated estimates of the pulsar velocity distribution, realistic hydrogen atmosphere spectra, and a modified expression for the Bondi accretion rate, as suggested by recent MHD simulations and supported by direct observations in the case of accretion around supermassive black holes in nearby galaxies and in our own. We find that, whereas the inclusion of atmospheric spectra partly compensates for the reduction in the counts due to the higher mean velocities of the new distribution, the modified Bondi formula dramatically suppresses the source counts. The new predictions are consistent with a null detection at the ROSAT sensitivity.

ROSITA

AbstractThe Max‐Planck‐Institut für extraterrestrische Physik, the Astrophysikalisches Institut Potsdam, and the Institut für Astronomie und Astrophysik of the university of Tübingen, together with European cooperation partners and ESA, plan to install an X‐ray telescope on the International Space Station (ISS). The mission ROSITA (ROentgen Survey with an Imaging Telescope Array) will perform the first imaging all‐sky survey in the medium energy X‐ray range up to 10 keV with an unprecedented spectral and angular resolution. The main scientific goals are (1) to detect systematically all obscured accreting Black Holes in nearby galaxies and altogether about 50,000 AGN in the 2‐10 keV band, (2) to detect the hot intergalactic medium of several ten thousand galaxy clusters, and (3) to study in detail the physics of galactic X‐ray source populations, like pre‐main sequence stars, supernova remnants, and X‐ray binaries. In the hard X‐ray band (above 2 keV) the ROSITA survey will have a hundred times higher sensitivity and a hundred times better angular resolution than the last all‐sky survey in this band, which was performed about 25 years ago. In the soft band (0.5‐2 keV) the ROSITA survey will be more sensitive and have a substantially better energy and also angular resolution than the ROSAT all‐sky survey. The telescope will consist of seven 27‐fold nested Wolter‐1 mirror systems, the type already flown on ABRIXAS, and a novel detector system currently being developed by MPE on the basis of the successful XMM pn‐CCD technology. Major improvements of the new camera are a higher time and energy resolution.

On the formation rate of close binaries consisting of a super-massive black hole and a white dwarf

The formation rate of a close binary consisting of a super-massive black hole and a compact object (presumably a white dwarf) in galactic cusps is calculated with the help of the so-called loss cone approximation. For a power-law cusp of radius ra, the black hole mass M ∼ 10 6 M� , and the fraction of the compact objects δ ∼ 0.1, this rate ˙ Nwd ∼ 4 · 10 −5 K ( p) [( GM )/(r 3 )] ≈ 3 × 10 −9 K ( p)(M/10 6 M� ) 1/2 (ra/1 pc) −3/2 yr −1 . The function K ( p) depends on parameter p determining the cusp profile, and for the standard cusp profiles with p = 1/4, K ( p) ∼ 2. We estimate the probability Pr of finding of a compact object orbiting around a black hole with the period P in one particular galaxy to be Pr ∼ 10 −7 [(P/10 3 s)/(M/10 6 M� )] 8/3 [(M/10 6 M� )/(ra/1 pc)] 3/2 . The object with the period P ∼ 10 3 s emits gravitational waves with amplitude sufficient to be detected by the LISAtype gravitational wave antenna from the distance ∼10 3 Mpc. Based on estimates of masses of super-massive black holes in nearby galaxies, we speculate that LISA would detect several such events during its mission.

Diffractive/refractive optics for high energy astronomy

Diffractive optics components such as Fresnel Zone Plates and their derivatives potentially form the basis for telescope systems for X-ray and gamma-ray astronomy with high sensitivity and superb angular resolution. The main problem is that systems with convenient design parameters involve very long focal lengths. The design considerations and performance of telescopes using a simple Phase Fresnel Lens on one spacecraft and a detector assembly on another are considered. Such systems are shown to have the potential to provide orders of magnitude improvement on currently available sensitivity. At the same time the angular resolution can be at the micro arcsecond level or better -sufficient to resolve the structure surrounding the event horizon of black holes in nearby galaxies.

Limits on the Accretion Rates onto Massive Black Holes in Nearby Galaxies

The radio emission from supermassive black holes in nearby early-type galaxies can be used to test possible explanations for their low luminosities. We calculate the expected contribution from thermal synchrotron emission from hot accretion flows to the high radio frequency observations of NGC 2300, NGC 1399, NGC 4278 and NGC 4594. We find that, in all cases, and in accordance with our previous findings, hot flows accreting close to their Bondi rates overestimate significantly the observed fluxes. This implies that simply assuming a low radiative efficiency for the accreting gas is not enough to explain their low luminosities. Smaller central densities and accretion rates, as expected in the presence of strong mass loss or convection in the flows, can help reconcile the models with observations. We also show that a significant contribution to the high-frequency radio spectra can be due to non-thermal synchrotron emission from the small scale radio jets observed in these systems, allowing for even lower accretion rates in the inflows. We suggest that these outflows or jets may dump significant energy into the surronding medium close to the accretion radius and so reduce the accretion rates onto these systems. We discuss the relationship between the radio flux and black hole mass for the observed sample and its potential importance for probing accretion models.

The Centers of Early-Type Galaxies with HST. IV. Central Parameter Relations.

We analyze Hubble Space Telescope surface-brightness profiles of 61 elliptical galaxies and spiral bulges (hot galaxies). Luminous hot galaxies have cuspy cores with steep outer power-law profiles that break at r ~ r_b to shallow inner profiles with logslope less than 0.3. Faint hot galaxies show steep, largely featureless power-law profiles at all radii and lack cores. The centers of power-law galaxies are up to 1000 times denser in mass and luminosity than the cores of large galaxies at a limiting radius of 10 pc. At intermediate magnitudes (-22.0 < M_V < -20.5), core and power-law galaxies coexist, and there is a range in r_b at a given luminosity of at least two orders of magnitude. Central properties correlate with global rotation and shape: core galaxies tend to be boxy and slowly rotating, whereas power-law galaxies tend to be disky and rapidly rotating. The dense power-law centers of disky, rotating galaxies are consistent with their formation in gas-rich mergers. The parallel proposition that cores are simply the by-products of gas-free stellar mergers is less compelling. For example, core galaxies accrete small, dense, gas-free galaxies at a rate sufficient to fill in low-density cores if the satellites survived and sank to the center. An alternative model for core formation involves the orbital decay of massive black holes (BHs): the BH may heat and eject stars from the center, eroding a power law if any exists and scouring out a core. An average BH mass per spheroid of 0.002 times the stellar mass yields reasonably good agreement with the masses and radii of observed cores and in addition is consistent with the energetics of AGNs and kinematic detections of BHs in nearby galaxies.

Massive Black Holes in Nearby Galaxies

Annals of the New York Academy of SciencesVolume 688, Issue 1 p. 716-720 Massive Black Holes in Nearby Galaxies DOUGLAS RICHSTONE, DOUGLAS RICHSTONE Department of Astronomy University of Michigan Ann Arbor, Michigan 48109Search for more papers by this author DOUGLAS RICHSTONE, DOUGLAS RICHSTONE Department of Astronomy University of Michigan Ann Arbor, Michigan 48109Search for more papers by this author First published: June 1993 https://doi.org/10.1111/j.1749-6632.1993.tb43961.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume688, Issue1Texas/Pascos '92: Relativistic Astrophysics and Particle CosmologyJune 1993Pages 716-720 RelatedInformation

Causes and effects of the first quasars.

The light we observe from the most distant known quasars set out when the Universe was about 200 times denser than it is now and less than one-tenth of its present age. The existence of these objects implies that galaxy formation had already, at that early epoch, proceeded to the stage when massive (>10(8)M[symbol, see text]) objects had accumulated in the centers of at least some young galaxies. A specific model is presented to show that the evolution and luminosity function of quasars are compatible with the cold dark matter cosmogony. Most big galaxies probably passed through a quasar phase; the remnant black holes in nearby galaxies may reveal themselves via the flares that occur whenever a star passes too close to them and gets tidally disrupted. The rich absorption spectra of quasars serve as a probe of the intervening medium. The gas responsible for the Lyman alpha absorption lines may be due to primordial gas gravitationally confined in minihalos of dark matter--shallow potential wells whose evolution and relation to dwarf galaxies are briefly discussed. The patchy heat input into the intergalactic medium from early quasars could modulate the environment in which galaxies form, leading to large-scale spatial correlations in the galaxy distribution. This review concludes with general comments on the prospects for a fully quantitative understanding of galaxy formation.