scholarly journals Toward Determining the Number of Observable Supermassive Black Hole Shadows

2021 ◽  
Vol 923 (2) ◽  
pp. 260
Author(s):  
Dominic W. Pesce ◽  
Daniel C. M. Palumbo ◽  
Ramesh Narayan ◽  
Lindy Blackburn ◽  
Sheperd S. Doeleman ◽  
...  
Keyword(s):  
Black Hole ◽  
Spectral Energy Distribution ◽  
Large Population ◽  
Second Order ◽  
Distribution Model ◽  
Spectral Energy ◽  
Current Event ◽  
First Order ◽  
Supermassive Black Hole ◽  
Many Sources

Abstract We present estimates for the number of shadow-resolved supermassive black hole (SMBH) systems that can be detected using radio interferometers, as a function of angular resolution, flux density sensitivity, and observing frequency. Accounting for the distribution of SMBHs across mass, redshift, and accretion rate, we use a new semianalytic spectral energy distribution model to derive the number of SMBHs with detectable and optically thin horizon-scale emission. We demonstrate that (sub)millimeter interferometric observations with ∼0.1 μas resolution and ∼1 μJy sensitivity could access >106 SMBH shadows. We then further decompose the shadow source counts into the number of black holes for which we could expect to observe the first- and second-order lensed photon rings. Accessing the bulk population of first-order photon rings requires ≲2 μas resolution and ≲0.5 mJy sensitivity, whereas doing the same for second-order photon rings requires ≲0.1 μas resolution and ≲5 μJy sensitivity. Our model predicts that with modest improvements to sensitivity, as many as ∼5 additional horizon-resolved sources should become accessible to the current Event Horizon Telescope (EHT), whereas a next-generation EHT observing at 345 GHz should have access to ∼3 times as many sources. More generally, our results can help guide enhancements of current arrays and specifications for future interferometric experiments that aim to spatially resolve a large population of SMBH shadows or higher-order photon rings.

scholarly journals SUPERMASSIVE BLACK HOLE BINARIES AT HIGH ENERGIES

2014 ◽  
Vol 28 ◽  
pp. 1460183
Author(s):  
GUSTAVO E. ROMERO ◽  
DANIELA PÉREZ ◽  
GABRIELA S. VILA
Keyword(s):  
Black Hole ◽  
Accretion Disk ◽  
Spectral Energy Distribution ◽  
Radiative Properties ◽  
Spectral Energy ◽  
Electromagnetic Spectrum ◽  
Relativistic Electrons ◽  
Black Hole Binaries ◽  
Supermassive Black Hole ◽  
Tidal Torques

An accretion disk around a supermassive black hole may be strongly perturbed by the presence of a secondary black hole. Recent simulations have shown that, under certain conditions, the tidal torques exerted by the secondary black hole may open an annular gap in the disk. In this regime, matter "overflows" across the secondary's orbit to accrete onto the primary and may feed a pair of relativistic jets. In this work we study the radiative properties of a binary system of supermassive black holes, assuming that a relativistic jet is launched from the primary and the migration of the secondary across the disk proceeds in the "overflowing" regime. The modified radiative spectrum of the disk is calculated accounting for strong gravitational effects in the innermost region. The jet emits non-thermal radiation all along the electromagnetic spectrum by interaction of locally accelerated electrons with the jet's magnetic field and internal and external radiation. In particular, we investigate whether the interaction of the relativistic electrons with the photons emitted by the accretion disk induces any signature in the spectral energy distribution of the jet that may reveal the presence of the secondary black hole.

scholarly journals A hierarchical bayesian dust SED model and its application to the nearby universe

2019 ◽  
Vol 15 (S341) ◽  
pp. 138-142
Author(s):  
Frédéric Galliano
Keyword(s):  
Spectral Energy Distribution ◽  
Distribution Model ◽  
Spectral Energy ◽  
Nearby Galaxy ◽  
Hierarchical Bayesian ◽  
Galaxy Sample ◽  
Hierarchical Bayesian Method ◽  
The One ◽  
Dust Evolution ◽  
Gas Ratio

AbstractIn this paper, I review several dust evolution studies based on the DustPedia nearby galaxy sample. I first present the dust spectral energy distribution model, implementing a hierarchical Bayesian method, that we have developed. I then discuss the dust evolution trends we have derived among (integrated) and within (resolved) galaxies. In particular, we show that the trend of dust-to-gas ratio with metallicity is clearly non-linear, indicating the need for grain growth in the interstellar medium. Our trend is closer to the one derived with damped Lyα systems than what was suggested by previous studies. We finally demonstrate the universal processing of small amorphous carbon grains by stellar photons.

scholarly journals Radiation from rapidly rotating oblate neutron stars

2018 ◽  
Vol 615 ◽  
pp. A50 ◽  
Author(s):  
J. Nättilä ◽  
P. Pihajoki
Keyword(s):  
Neutron Stars ◽  
Spectral Energy Distribution ◽  
Numerical Algorithms ◽  
Second Order ◽  
Compact Objects ◽  
Spectral Energy ◽  
Full Width ◽  
Millisecond Pulsars ◽  
Frame Dragging ◽  
Jacobi Formalism

A theoretical framework for emission originating from rapidly rotating oblate compact objects is described in detail. Using a Hamilton-Jacobi formalism, we show that special relativistic rotational effects such as aberration of angles, Doppler boosting, and time dilatation naturally emerge from the general relativistic treatment of rotating compact objects. We use the Butterworth–Ipser metric expanded up to the second order in rotation and hence include effects of light bending, frame-dragging, and quadrupole deviations on our geodesic calculations. We also give detailed descriptions of the numerical algorithms used and provide an open-source implementation of the numerical framework called BENDER. As an application, we study spectral line profiles (i.e., smearing kernels) from rapidly rotating oblate neutron stars. We find that in this metric description, the second-order quadrupole effects are not strong enough to produce narrow observable features in the spectral energy distribution for almost any physically realistic parameter combination, and hence, actually detecting them is unlikely. The full width at tenth-maximum and full width at half-maximum of the rotation smearing kernels are also reported for all viewing angles. These can then be used to quantitatively estimate the effects of rotational smearing on the observed spectra. We also calculate accurate pulse profiles and observer skymaps of emission from hot spots on rapidly rotating accreting millisecond pulsars. These allow us to quantify the strength of the pulse fractions one expects to observe from typical fast-spinning millisecond pulsars.

scholarly journals Multiwavelength analysis as a probe of accretion and radiative processes in LINERs

2012 ◽  
Vol 8 (S290) ◽  
pp. 355-356
Author(s):  
George Younes ◽  
Delphine Porquet
Keyword(s):  
Black Hole ◽  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Spectral Characteristics ◽  
Spectral Energy ◽  
X Ray ◽  
Radiative Processes ◽  
Central Engine ◽  
Galactic Black Hole ◽  
X Ray Binaries

AbstractWe study the multiwavelength properties of an optically selected sample of Low Ionization Nuclear Emission-line Regions (LINERs), in an attempt to determine the accretion mechanism powering their central engine. We show how their X-ray spectral characteristics, and their spectral energy distribution compare to luminous AGN, and briefly discuss their connection to their less massive counter-parts galactic black-hole X-ray binaries.

scholarly journals X-ray and optical observations of the black hole candidate MAXI J1828−249

2019 ◽  
Vol 71 (5) ◽  
Author(s):  
Sonoe Oda ◽  
Megumi Shidatsu ◽  
Satoshi Nakahira ◽  
Toru Tamagawa ◽  
Yuki Moritani ◽  
...  
Keyword(s):  
Black Hole ◽  
Low Temperature ◽  
Power Law ◽  
Spectral Power ◽  
Spectral Energy Distribution ◽  
Disk Surface ◽  
Optical Observations ◽  
Spectral Energy ◽  
X Ray ◽  
Black Hole Candidate

Abstract We report results from X-ray and optical observations of the Galactic black hole candidate MAXI J1828−249 performed with Suzaku and the Kanata telescope around the X-ray flux peak in the 2013 outburst. The time-averaged X-ray spectrum covering 0.6–168 keV was approximately characterized by a strong multi-color disk blackbody component with an inner disk temperature of ∼0.6 keV, and a power-law tail with a photon index of ∼2.0. We detected an additional structure at 5–10 keV, which can be modeled neither with X-ray reflection on the disk nor relativistic broadening of the disk emission. Instead, it was successfully reproduced with a Comptonization of disk photons by thermal electrons with a relatively low temperature (≲10 keV). We infer that the source was in the intermediate state, considering its long-term trend in the hardness intensity diagram, the strength of the spectral power-law tail, and its variability properties. The low-temperature Comptonization component could be produced in a boundary region between the truncated standard disk and the hot inner flow, or a Comptonizing region that somehow developed above the disk surface. The multi-wavelength spectral energy distribution suggests that the optical and ultraviolet fluxes were dominated by irradiated outer disk emission.

scholarly journals Geometric Curvatures of Plane Symmetry Black Hole

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Shao-Wen Wei ◽  
Yu-Xiao Liu ◽  
Chun-E. Fu ◽  
Hai-Tao Li
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
Order Phase Transition ◽  
Semiclassical Approximation ◽  
Second Order ◽  
Plane Symmetry ◽  
First Order ◽  
First Order Phase Transition ◽  
Transition Points ◽  
First Order Phase

We study the properties and thermodynamic stability of the plane symmetry black hole from the viewpoint of geometry. We find that the Weinhold curvature gives the first-order phase transition atN=1, whereNis a parameter of the plane symmetry black hole while the Ruppeiner one shows first-order phase transition points for arbitraryN≠1. Considering the Legendre invariant proposed by Quevedo et al., we obtain a unified geometry metric, which contains the information of the second-order phase transition. So, the first-order and second-order phase transitions can be both reproduced from the geometry curvatures. The geometry is also found to be curved, and the scalar curvature goes to negative infinity at the Davie phase transition points beyond semiclassical approximation.

scholarly journals THE EVENT HORIZON OF THE SCHWARZSCHILD BLACK HOLE IN NONCOMMUTATIVE SPACES

2006 ◽  
Vol 15 (07) ◽  
pp. 1113-1117 ◽  
Author(s):  
FOROUGH NASSERI
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Lower Limit ◽  
Second Order ◽  
Schwarzschild Black Hole ◽  
Perturbative Calculations ◽  
First Order ◽  
Noncommutative Spaces

The event horizon of the Schwarzschild black hole is obtained in noncommutative spaces up to the second order of perturbative calculations. Because this type of black hole is non-rotating, to the first order there is no effect on the event horizon due to the noncommutativity of space. A lower limit for the noncommutativity parameter is also obtained. As a result, the event horizon in noncommutative spaces is less than the event horizon in commutative spaces.

scholarly journals Modelling the spectral energy distribution of super-Eddington quasars

2019 ◽  
Vol 489 (1) ◽  
pp. 524-533 ◽  
Author(s):  
Aya Kubota ◽  
Chris Done
Keyword(s):  
Black Hole ◽  
Spectral Energy Distribution ◽  
Broad Band ◽  
Spectral Energy ◽  
Band Spectrum ◽  
Physical Constraints ◽  
Black Hole Accretion ◽  
Accretion Rates ◽  
Eddington Limit ◽  
Standard Disc

ABSTRACT We develop a broad-band spectral model, agnslim, to describe super-Eddington black hole accretion disc spectra. This is based on the slim disc emissivity, where radial advection keeps the surface luminosity at the local Eddington limit, resulting in L(r) ∝ r−2 rather than the r−3 expected from the Novikov-Thorne (standard, sub-Eddington) disc emissivity. Wind losses should also be important but these are expected to produce a similar radiative emissivity. We assume that the flow is radially stratified, with an outer standard disc, an inner hot Comptonizing region and an intermediate warm Comptonizing region to produce the soft X-ray excess. This gives the model enough flexibility to fit the observed data, but with the additional requirement of energy conservation to give physical constraints. We use this to fit the broad-band spectrum of one of the most extreme Active Galactic Nuclei, the Narrow Line Seyfert 1 RX J0439.6−5311, which has a black hole mass of $(6\sim 9)\times 10^6\, \mathrm{M}_\odot$ as derived from the H β line width. This cannot be fit with the standard disc emissivity at this mass, as even zero spin models overproduce the observed luminosity. Instead, we show that the spectrum is well reproduced by the slim disc model, giving mass accretion rates around (5 ∼ 10) × Eddington limit. There is no constraint on black hole spin as the efficiency is reduced by advection. Such extreme accretion rates should be characteristic of the first Quasars, and we demonstrate this by fitting to the spectrum of a recently discovered super-Eddington Quasar, PSO J006 + 39, at z = 6.6.

scholarly journals The Spectral Energy Distribution of Quiescent Black Hole X‐Ray Binaries: New Constraints fromSpitzer

2007 ◽  
Vol 670 (1) ◽  
pp. 600-609 ◽  
Author(s):  
Elena Gallo ◽  
Simone Migliari ◽  
Sera Markoff ◽  
John A. Tomsick ◽  
Charles D. Bailyn ◽  
...  
Keyword(s):  
Black Hole ◽  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
X Ray ◽  
X Ray Binaries

scholarly journals Extreme submillimetre starburst galaxies

2018 ◽  
Vol 619 ◽  
pp. A169 ◽  
Author(s):  
M. Rowan-Robinson ◽  
Lingyu Wang ◽  
Duncan Farrah ◽  
Dimitra Rigopoulou ◽  
Carlotta Gruppioni ◽  
...  
Keyword(s):  
Black Hole ◽  
Star Formation ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Optical Emission ◽  
Spectral Energy ◽  
Black Hole Growth ◽  
Show Evidence ◽  
Universal Ratio

We have used two catalogues, a Herschel catalogue selected at 500 μm (HerMES) and an IRAS catalogue selected at 60 μm (RIFSCz), to contrast the sky at these two wavelengths. Both surveys demonstrate the existence of “extreme” starbursts, with star-formation rates (SFRs) > 5000 M⊙ yr−1. The maximum intrinsic star-formation rate appears to be ~30 000 M⊙ yr−1. The sources with apparent SFR estimates higher than this are in all cases either lensed systems, blazars, or erroneous photometric redshifts. At redshifts between three and five, the time-scale for the Herschel galaxies to make their current mass of stars at their present rate of star formation is ~108 yr, so these galaxies are making a significant fraction of their stars in the current star-formation episode. Using dust mass as a proxy for gas mass, the Herschel galaxies at redshift three to five have gas masses comparable to their mass in stars. Of the 38 extreme starbursts in our Herschel survey for which we have more complete spectral energy distribution (SED) information, 50% show evidence for QSO-like optical emission, or exhibit AGN dust tori in the mid-infrared SEDs. In all cases however the infrared luminosity is dominated by a starburst component. We derive a mean covering factor for AGN dust as a function of redshift and derive black hole masses and black hole accretion rates. There is a universal ratio of black-hole mass to stellar mass in these high redshift systems of ~10−3, driven by the strong period of star-formation and black-hole growth at z = 1−5.

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