scholarly journals Constraining the masses of microlensing black holes and the mass gap with Gaia DR2

2020 ◽  
Vol 636 ◽  
pp. A20 ◽  
Author(s):  
Łukasz Wyrzykowski ◽  
Ilya Mandel
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Stars ◽  
Continuous Distribution ◽  
Compact Object ◽  
Proper Motions ◽  
Mass Gap ◽  
Wide Range ◽  
The Masses ◽  
Black Hole Masses

Context. Gravitational microlensing is sensitive to compact-object lenses in the Milky Way, including white dwarfs, neutron stars, or black holes, and could potentially probe a wide range of stellar-remnant masses. However, the mass of the lens can be determined only in very limited cases, due to missing information on both source and lens distances and their proper motions. Aims. Our aim is to improve the mass estimates in the annual parallax microlensing events found in the eight years of OGLE-III observations towards the Galactic Bulge with the use of Gaia Data Release 2 (DR2). Methods. We use Gaia DR2 data on distances and proper motions of non-blended sources and recompute the masses of lenses in parallax events. We also identify new events in that sample which are likely to have dark lenses; the total number of such events is now 18. Results. The derived distribution of masses of dark lenses is consistent with a continuous distribution of stellar-remnant masses. A mass gap between neutron star and black hole masses in the range between 2 and 5 solar masses is not favoured by our data, unless black holes receive natal kicks above 20−80 km s−1. We present eight candidates for objects with masses within the putative mass gap, including a spectacular multi-peak parallax event with mass of 2.4−1.3+1.9 M⊙ located just at 600 pc. The absence of an observational mass gap between neutron stars and black holes, or conversely the evidence of black hole natal kicks if a mass gap is assumed, can inform future supernova modelling efforts.

scholarly journals Toward Precision Measurement of Central Black Hole Masses

2009 ◽  
Vol 5 (S267) ◽  
pp. 151-160 ◽  
Author(s):  
Bradley M. Peterson
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Host Galaxy ◽  
Reverberation Mapping ◽  
Line Region ◽  
The Masses ◽  
The Relationship ◽  
Black Hole Masses ◽  
Intrinsic Scatter ◽  
Direct And Indirect Methods

AbstractWe review briefly direct and indirect methods of measuring the masses of black holes in galactic nuclei, and then focus attention on supermassive black holes in active nuclei, with special attention to results from reverberation mapping and their limitations. We find that the intrinsic scatter in the relationship between the AGN luminosity and the broad-line region size is very small, ~0.11 dex, comparable to the uncertainties in the better reverberation measurements. We also find that the relationship between reverberation-based black hole masses and host-galaxy bulge luminosities also seems to have surprisingly little intrinsic scatter, ~0.17 dex. We note, however, that there are still potential systematics that could affect the overall mass calibration at the level of a factor of a few.

scholarly journals Quasar Mass Functions Across Cosmic Time

2009 ◽  
Vol 5 (S267) ◽  
pp. 239-247
Author(s):  
Marianne Vestergaard
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cosmic Time ◽  
Wide Range ◽  
Mass Functions ◽  
Black Hole Masses ◽  
Cosmic History

AbstractI present mass functions of actively accreting black holes detected in different quasar surveys which in concert cover a wide range of cosmic history. I briefly address what we learn from these mass functions. I summarize the motivation for such a study and the methods by which we determine black hole masses.

scholarly journals Accurate AGN Black Hole Masses and the Scatter in the MBH–Lbulge Relationship

2009 ◽  
Vol 5 (S267) ◽  
pp. 203-203 ◽  
Author(s):  
C. Martin Gaskell
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Velocity Dispersion ◽  
High Luminosity ◽  
Lower Mass ◽  
Reverberation Mapping ◽  
The Masses ◽  
Black Hole Masses ◽  
The Continuum

AbstractA new empirical formulae is given for estimating the masses of black holes in AGNs from the Hβ velocity dispersion and the continuum luminosity at 5100 Å. It is calibrated to reverberation-mapping and stellar-dynamical estimates of black hole masses. The resulting mass estimates are as accurate as reverberation-mapping and stellar-dynamical estimates. The new mass estimates show that there is very little scatter in the MBH–Lbulge relationship for high-luminosity galaxies, and that the scatter increases substantially in lower-mass galaxies.

scholarly journals Uncertainties of the masses of black holes and Eddington ratios in AGN

2006 ◽  
Vol 2 (S238) ◽  
pp. 111-116
Author(s):  
Suzy Collin
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Reverberation Mapping ◽  
Line Region ◽  
Region I ◽  
Accretion Rates ◽  
Unknown Structure ◽  
The Masses ◽  
Empirical Size ◽  
Black Hole Masses

AbstractBlack hole masses in Active Galactic Nuclei have been determined in 35 objects through reverberation mapping of the emission line region. I mention some uncertainties of the method, such as the “scale factor” relating the Virial Product to the mass, which depends on the unknown structure and dynamics of the Broad Line Region.When the black hole masses are estimated indirectly using the empirical size-luminosity relation deduced from this method, the uncertainties can be larger, especially when the relation is extrapolated to high and low masses and/or luminosities. In particular they lead to Eddington ratiosof the order of unity in samples of Narrow Line Seyfert 1. As the optical-UV luminosity is provided by the accretion disk, the accretion rates can be determined and are found to be much larger than the Eddington rates.So, accretion must be performed at a super-critical rate through a slim disk, resulting in rapid growth of the black holes. The alternative is that the mass determination is wrong at this limit.

scholarly journals SUPER

2020 ◽  
Vol 644 ◽  
pp. A175
Author(s):  
G. Vietri ◽  
V. Mainieri ◽  
D. Kakkad ◽  
H. Netzer ◽  
M. Perna ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Line Profile ◽  
Host Galaxy ◽  
X Ray ◽  
Bolometric Luminosity ◽  
Line Region ◽  
The Masses ◽  
Black Hole Masses

Aims. The SINFONI survey for Unveiling the Physics and Effect of Radiative feedback (SUPER) was designed to conduct a blind search for AGN-driven outflows on X-ray-selected AGNs at redshift z ∼ 2 with high (∼2 kpc) spatial resolution, and to correlate them with the properties of their host galaxy and central black hole. The main aims of this paper are: (a) to derive reliable estimates for the masses of the black holes and accretion rates for the Type-1 AGNs in this survey; and (b) to characterise the properties of the AGN-driven winds in the broad line region (BLR). Methods. We analysed rest-frame optical and UV spectra of 21 Type-1 AGNs. We used Hα, Hβ, and MgII line profiles to estimate the masses of the black holes. We used the blueshift of the CIV line profile to trace the presence of winds in the BLR. Results. We find that the Hα and Hβ line widths are strongly correlated, as is the line continuum luminosity at 5100 Å with Hα line luminosity, resulting in a well-defined correlation between black hole masses estimated from Hα and Hβ. Using these lines, we estimate that the black hole masses for our objects are in the range Log (MBH/M⊙) = 8.4–10.8 and are accreting at λEdd = 0.04–1.3. Furthermore, we confirm the well-known finding that the CIV line width does not correlate with the Balmer lines and the peak of the line profile is blueshifted with respect to the [OIII]-based systemic redshift. These findings support the idea that the CIV line is tracing outflowing gas in the BLR for which we estimated velocities up to ∼4700 km s−1. We confirm the strong dependence of the BLR wind velocity on the UV-to-X-ray continuum slope, the bolometric luminosity, and Eddington ratio. We infer BLR mass outflow rates in the range 0.005–3 M⊙ yr−1, revealing a correlation with the bolometric luminosity consistent with that observed for ionised winds in the narrow line region (NLR), and X-ray winds detected in local AGNs, and kinetic power ∼10−7 − 10−4 × LBol. The coupling efficiencies predicted by AGN-feedback models are much higher than the values reported for the BLR winds in the SUPER sample; although it should be noted that only a fraction of the energy injected by the AGN into the surrounding medium is expected to become kinetic power in the outflow. Finally, we find an anti-correlation between the equivalent width of the [OIII] line and the CIV velocity shift, and a positive correlation between this latter parameter and [OIII] outflow velocity. These findings, for the first time in an unbiased sample of AGNs at z ∼ 2, support a scenario where BLR winds are connected to galaxy-scale detected outflows, and are therefore capable of affecting the gas in the NLR located at kiloparsec scale distances.

scholarly journals Investigating ultraluminous X-ray sources through their multiwavelength variability and broadband spectra

2016 ◽  
Vol 12 (S324) ◽  
pp. 31-34
Author(s):  
Luca Zampieri ◽  
Elena Ambrosi ◽  
Amid Nayerhoda
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Stars ◽  
Compact Objects ◽  
Intermediate Mass ◽  
Local Universe ◽  
X Ray ◽  
Multiwavelength Variability ◽  
Black Hole Masses ◽  
Eddington Limit

AbstractThe population of ultraluminous X-ray sources encompasses accreting compact objects with significantly different masses, from black holes of intermediate mass, to black holes of stellar origin, to neutron stars. Investigating these sources will help us answering crucial questions on the distribution of black hole masses and on mass accretion above the Eddington limit in the local Universe, that have potential implications in other astrophysical areas. In order to perform a detailed investigation of ultraluminous X-ray sources, an accurate modeling of their evolution and multiwavelength emission properties is needed. We report some preliminary results of the activities that we are carrying out at present in this area.

scholarly journals Recent LIGO-Virgo discoveries

2021 ◽  
pp. 2130010
Author(s):  
Maximiliano Isi
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Neutron Star ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Compact Objects ◽  
Tests Of General Relativity ◽  
Mass Gap ◽  
Cosmic History

The LIGO and Virgo gravitational-wave detectors carried out the first half of their third observing run from April through October 2019. During this period, they detected 39 new signals from the coalescence of black holes or neutron stars, more than quadrupling the total number of detected events. These detections included some unprecedented sources, like a pair of black holes with unequal masses (GW190412), a massive pair of neutron stars (GW190425), a black hole potentially in the supernova pair-instability mass gap (GW190521), and either the lightest black hole or the heaviest neutron star known to date (GW190814). Collectively, the full set of signals provided astrophysically valuable information about the distributions of compact objects and their evolution throughout cosmic history. It also enabled more constraining and diverse tests of general relativity, including new probes of the fundamental nature of black holes. This review summarizes the highlights of these results and their implications.

scholarly journals Black Holes in the Universe

1998 ◽  
Vol 11 (1) ◽  
pp. 28-41
Author(s):  
I.D. Novikov
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Stars ◽  
Supernova Explosions ◽  
The Universe

Some 30 years ago very few scientists thought that black holes may really exist. Attention focussed on the black hole hypothesis after neutron stars had been discovered. It was rather surprising that astrophysicists immediately ‘welcomed’ black holes. They found their place not only in the remnants of supernova explosions but also in the nuclei of galaxies and quasars.

scholarly journals Cosmological black holes are not described by the Thakurta metric: LIGO-Virgo bounds on PBHs remain unchanged

2021 ◽  
Vol 81 (11) ◽  
Author(s):  
Gert Hütsi ◽  
Tomi Koivisto ◽  
Martti Raidal ◽  
Ville Vaskonen ◽  
Hardi Veermäe
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Compact Object ◽  
Compact Objects ◽  
Primordial Black Hole ◽  
Mass Growth ◽  
Black Hole Binaries ◽  
Physical Conditions ◽  
Accretion Physics

AbstractWe show that the physical conditions which induce the Thakurta metric, recently studied by Bœhm et al. in the context of time-dependent black hole masses, correspond to a single accreting compact object in the entire Universe filled with isotropic non-interacting dust. In such a case, accretion physics is not local but tied to the properties of the whole Universe. We show that radiation, primordial black holes or particle dark matter cannot produce the specific energy flux required for supporting the mass growth of the compact objects described by the Thakurta metric. In particular, this solution does not apply to black hole binaries. We conclude that compact dark matter candidates and their mass growth cannot be described by the Thakurta metric, and thus existing constraints on the primordial black hole abundance from the LIGO-Virgo and the CMB measurements remain valid.

3. Extrasolar tests of gravity

2017 ◽  
pp. 35-45
Author(s):  
Timothy Clifton
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Field ◽  
Solar System ◽  
Neutron Stars ◽  
Event Horizon ◽  
Gravitational Fields ◽  
Binary Pulsars ◽  
Tests Of Gravity ◽  
Triple Star

By studying objects outside our Solar System, we can observe star systems with far greater gravitational fields. ‘Extrasolar tests of gravity’ considers stars of different sizes that have undergone gravitational collapse, including white dwarfs, neutron stars, and black holes. A black hole consists of a region of space-time enclosed by a surface called an event horizon. The gravitational field of a black hole is so strong that anything that finds its way inside the event horizon can never escape. Other star systems considered are binary pulsars and triple star systems. With the invention of even more powerful telescopes, there will be more tantalizing possibilities for testing gravity in the future.

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