scholarly journals Probing within the bondi radius of the ultramassive black hole in NGC 1600

2021 ◽  
Author(s):  
J Runge ◽  
S A Walker
Keyword(s):  
Black Hole ◽  
Accretion Rate ◽  
Statistical Significance ◽  
Large Mass ◽  
Nearby Galaxy ◽  
Density Profiles ◽  
Spatially Resolved ◽  
Single Temperature ◽  
Slight Rise ◽  
Two Temperature

Abstract We present deep (250 ks) Chandra observations of the nearby galaxy group NGC 1600, which has at its centre an ultramassive black hole (17±1.5 billion M⊙). The exceptionally large mass of the black hole coupled with its low redshift makes it one of only a handful of black holes for which spatially resolved temperature and density profiles can be obtained within the Bondi radius with the high spatial resolution of Chandra. We analyzed the hot gas properties within the Bondi accretion radius R$_\rm {B}=1{_{.}^{\prime\prime}} 2 - 1{_{.}^{\prime\prime}} 7= 0.38 - 0.54~\rm {kpc}$. Within a ∼3 kpc radius, we find two temperature components with statistical significance. Both the single temperature and two temperature models show only a very slight rise in temperature towards the centre, and are consistent with being flat. This is in contrast with the expectation from Bondi accretion for a temperature profile which increases towards the centre, and appears to indicate that the dynamics of the gas are not being determined by the central black hole. The density profile follows a relatively shallow ρ∝ r−[0.61 ± 0.13] relationship within the Bondi radius, which suggests that the true accretion rate on to the black hole may be lower than the classical Bondi accretion rate.

scholarly journals General relativistic two-temperature accretion solutions for spherical flows around black holes

2019 ◽  
Vol 28 (02) ◽  
pp. 1950037 ◽  
Author(s):  
Shilpa Sarkar ◽  
Indranil Chattopadhyay
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Accretion Rate ◽  
Second Law Of Thermodynamics ◽  
Massive Black Hole ◽  
Dissipative Heat ◽  
Single Temperature ◽  
Constants Of Motion ◽  
Heat Processes ◽  
Two Temperature

Matter falling onto black holes is hot, fully ionized and has to be necessarily transonic. Since the electrons are responsible for radiative cooling via processes like synchrotron, bremsstrahlung and inverse-Compton, the electron gas and proton gas are supposed to settle into two separate temperature distribution. But the problem with two-temperature flow is that there is one more variable than the number of equations. Accretion flow in its simplest form is radial, which has two constants of motion, while the flow variables are the radial bulk three-velocity, electron and proton temperatures. Therefore, unlike single temperature flow, in the two-temperature regime, there are multiple transonic solutions, nonunique for any given set of constants of motion with a large variation in sonic points. We invoked the second law of thermodynamics to find a possible way to break the degeneracy, by showing only one of the solutions among all possible, has maximum entropy and therefore is the correct solution. By considering these correct solutions, we showed that the accretion efficiency increase with the increase in the mass accretion rate. We showed that radial flow onto super-massive black hole can radiate with efficiency more than 10%, if the accretion rate is more than 60% of the Eddington accretion rate, but accretion onto stellar-mass black hole achieve the same efficiency, when it is close to the Eddington limit. We also showed that dissipative heat quantitatively affects the two temperature solution. In the presence of explicit heat processes, the Coulomb coupling is weak.

scholarly journals Quasar evolution: black hole mass and accretion rate determination

2006 ◽  
Vol 2 (S238) ◽  
pp. 83-86
Author(s):  
Deborah Dultzin-Hacyan ◽  
Paola Marziani ◽  
C. Alenka Negrete ◽  
Jack W. Sulentic
Keyword(s):  
Black Hole ◽  
Accretion Rate ◽  
Selection Effects ◽  
Black Hole Mass ◽  
Spectral Evolution ◽  
Spatially Resolved ◽  
Central Engine ◽  
Line Region ◽  
Ratio Determination ◽  
Almost All

AbstractAccurate measurements of emission line properties are crucial to understand the physics of the broad line region in quasars. This region consists of warm gas that is closest to the quasar central engine and has not been spatially resolved for almost all sources. We present here an analysis of optical and IR data for a large sample of quasars, covering the Hi Hβ spectral region in the redshift range 0 ≲ z ≲ 2.5. Spectra were interpreted within the framework of the the so-called “eigenvector 1” parameter space, which can be viewed as a tentative H-R diagram for quasars. We stress the lack of spectral evolution in the low ionization lines of quasars, with prominent Fe ii emission also at z ≳ 2. We also show how selection effects influence the ability to find quasars radiating at low Eddington ratio in flux-limited surveys. The quasar similarity at different redshift is probably due to the absence of super-Eddington radiators (at least within the caveats of black hole mass and Eddington ratio determination discussed in this paper) as well as to the limited Eddington ratio range within which quasars seem to radiate.

Central kiloparsec of NGC 1326 observed with SINFONI

2020 ◽  
Vol 638 ◽  
pp. A53
Author(s):  
Nastaran Fazeli ◽  
Gerold Busch ◽  
Andreas Eckart ◽  
Françoise Combes ◽  
Persis Misquitta ◽  
...  
Keyword(s):  
Black Hole ◽  
Galaxy Evolution ◽  
Near Infrared ◽  
Velocity Fields ◽  
Molecular Gas ◽  
Nearby Galaxy ◽  
Stellar Content ◽  
Stellar Rotation ◽  
Supermassive Black Hole ◽  
Integral Field Spectrograph

Gas inflow processes in the vicinity of galactic nuclei play a crucial role in galaxy evolution and supermassive black hole growth. Exploring the central kiloparsec of galaxies is essential to shed more light on this subject. We present near-infrared H- and K-band results of the nuclear region of the nearby galaxy NGC 1326, observed with the integral-field spectrograph SINFONI mounted on the Very Large Telescope. The field of view covers 9″ × 9″ (650 × 650 pc2). Our work is concentrated on excitation conditions, morphology, and stellar content. The nucleus of NGC 1326 was classified as a LINER, however in our data we observed an absence of ionised gas emission in the central r ∼ 3″. We studied the morphology by analysing the distribution of ionised and molecular gas, and thereby detected an elliptically shaped, circum-nuclear star-forming ring at a mean radius of 300 pc. We estimate the starburst regions in the ring to be young with dominating ages of < 10 Myr. The molecular gas distribution also reveals an elongated east to west central structure about 3″ in radius, where gas is excited by slow or mild shock mechanisms. We calculate the ionised gas mass of 8 × 105 M⊙ completely concentrated in the nuclear ring and the warm molecular gas mass of 187 M⊙, from which half is concentrated in the ring and the other half in the elongated central structure. The stellar velocity fields show pure rotation in the plane of the galaxy. The gas velocity fields show similar rotation in the ring, but in the central elongated H2 structure they show much higher amplitudes and indications of further deviation from the stellar rotation in the central 1″ aperture. We suggest that the central 6″ elongated H2 structure might be a fast-rotating central disc. The CO(3–2) emission observations with the Atacama Large Millimeter/submillimeter Array reveal a central 1″ torus. In the central 1″ of the H2 velocity field and residual maps, we find indications for a further decoupled structure closer to a nuclear disc, which could be identified with the torus surrounding the supermassive black hole.

scholarly journals Effective processing and evaluation of chemical imaging data with respect to morphological features of the zebrafish embryo

2021 ◽  
Author(s):  
Katharina Halbach ◽  
Timothy Holbrook ◽  
Thorsten Reemtsma ◽  
Stephan Wagner
Keyword(s):  
Inductively Coupled Plasma ◽  
Zebrafish Embryo ◽  
Statistical Significance ◽  
Software Tool ◽  
Chemical Imaging ◽  
Imaging Data ◽  
Inductively Coupled ◽  
Spatially Resolved ◽  
Icp Ms ◽  
Plasma Mass Spectrometry

AbstractA workflow was developed and implemented in a software tool for the automated combination of spatially resolved laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) data and data on the morphology of the biological tissue. Making use of a recently published biological annotation software, FishImager automatically assigns the biological feature as regions of interest (ROIs) and overlays them with the quantitative LA-ICP-MS data. Furthermore, statistical tools including cluster algorithms can be applied to the elemental intensity data and directly compared with the ROIs. This is effectively visualized in heatmaps. This allows gaining statistical significance on distribution and co-localization patterns. Finally, the biological functions of the assigned ROIs can then be easily linked with elemental distributions. We demonstrate the versatility of FishImager with quantitative LA-ICP-MS data of the zebrafish embryo tissue. The distribution of natural elements and xenobiotics is analyzed and discussed. With the help of FishImager, it was possible to identify compartments affected by toxicity effects or biological mechanisms to eliminate the xenobiotic. The presented workflow can be used for clinical and ecotoxicological testing, for example. Ultimately, it is a tool to simplify and reproduce interpretations of imaging LA-ICP-MS data in many applications. Graphical abstract

scholarly journals A full relativistic thin disc - the physics of the plunging region and the value of the stress at the ISCO

2021 ◽  
Author(s):  
William J Potter
Keyword(s):  
Black Hole ◽  
Surface Temperature ◽  
Accretion Rate ◽  
Speed Of Light ◽  
Thin Disc ◽  
Stable Circular Orbit ◽  
Stress Surface ◽  
Innermost Stable Circular Orbit ◽  
Turbulent Heating ◽  
Local Surface Temperature

Abstract The widely used Novikov-Thorne relativistic thin disc equations are only valid down to the radius of the innermost-stable circular orbit (ISCO). This leads to an undetermined boundary condition at the ISCO, known as the inner stress of the disc, which sets the luminosity of the disc at the ISCO and introduces considerable ambiguity in accurately determining the mass, spin and accretion rate of black holes from observed spectra. We resolve this ambiguity by self-consistently extending the relativistic disc solution through the ISCO to the black hole horizon by calculating the inspiral of an average disc particle subject to turbulent disc forces, using a new particle-in-disc technique. Traditionally it has been assumed that the stress at the ISCO is zero, with material plunging approximately radially into the black hole at close to the speed of light. We demonstrate that in fact the inspiral is less severe, with several (∼4 − 17) orbits completed before the horizon. This leads to a small non-zero stress and luminosity at and inside the ISCO, with a local surface temperature at the ISCO between ∼0.15 − 0.3 times the maximum surface temperature of the disc, in the case where no dynamically important net magnetic field is present. For a range of disc parameters we calculate the value of the inner stress/surface temperature, which is required when fitting relativistic thin disc models to observations. We resolve a problem in relativistic slim disc models in which turbulent heating becomes inaccurate and falls to zero inside the plunging region.

scholarly journals X-ray properties of reverberation-mapped AGNs with super-Eddington accreting massive black holes

2019 ◽  
Vol 15 (S356) ◽  
pp. 143-143
Author(s):  
Jaya Maithil ◽  
Michael S. Brotherton ◽  
Bin Luo ◽  
Ohad Shemmer ◽  
Sarah C. Gallagher ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Accretion Rate ◽  
Time Lags ◽  
Black Hole Mass ◽  
Host Galaxies ◽  
Massive Black Holes ◽  
X Ray ◽  
Photon Index ◽  
The Impact

AbstractActive Galactic Nuclei (AGN) exhibit multi-wavelength properties that are representative of the underlying physical processes taking place in the vicinity of the accreting supermassive black hole. The black hole mass and the accretion rate are fundamental for understanding the growth of black holes, their evolution, and the impact on the host galaxies. Recent results on reverberation-mapped AGNs show that the highest accretion rate objects have systematic shorter time-lags. These super-Eddington accreting massive black holes (SEAMBHs) show BLR size 3-8 times smaller than predicted by the Radius-Luminosity (R-L) relationship. Hence, the single-epoch virial black hole mass estimates of highly accreting AGNs have an overestimation of a factor of 3-8 times. SEAMBHs likely have a slim accretion disk rather than a thin disk that is diagnostic in X-ray. I will present the extreme X-ray properties of a sample of dozen of SEAMBHs. They indeed have a steep hard X-ray photon index, Γ, and demonstrate a steeper power-law slope, ασx.

scholarly journals Forming bulges during galaxy minor mergers

2007 ◽  
Vol 3 (S245) ◽  
pp. 63-66 ◽  
Author(s):  
T. J. Cox ◽  
J. Younger ◽  
L. Hernquist ◽  
P. F. Hopkins
Keyword(s):  
Black Hole ◽  
Large Mass ◽  
Elliptical Galaxies ◽  
Equal Mass ◽  
Mass Ratio ◽  
Black Hole Growth ◽  
Major Merger ◽  
Hole Growth ◽  
Minor Mergers ◽  
Large Mass Ratio

AbstractThe hierarchical formation of structure suggests that dark halos, and the galaxies they host, are shaped by their merging history. While the idea that mergers between galaxies of equal mass, i.e., major merger, produce elliptical galaxies has received considerable attention, he galaxies that result from minor merger, i.e., mergers between galaxies with a large mass ratio, is much less understood. We have performed a large number of numerical simulations of minor mergers, including cooling, star formation, and black hole growth in order to study this process in more detail. This talk will present some preliminary results of this study, and in particular, the morphology and kinematics of minor merger remnants.

scholarly journals Retract p < 0.005 and propose using JASP, instead

F1000Research ◽  
2018 ◽  
Vol 6 ◽  
pp. 2122 ◽  
Author(s):  
Jose D. Perezgonzalez ◽  
M. Dolores Frías-Navarro
Keyword(s):  
Statistical Significance ◽  
Life Sciences ◽  
Large Mass ◽  
Bayes Factors ◽  
Error Statistics ◽  
Factors Analysis ◽  
Original Argument ◽  
Potential Impact ◽  
Bayesian Prior

Seeking to address the lack of research reproducibility in science, including psychology and the life sciences, a pragmatic solution has been raised recently:  to use a stricter p < 0.005 standard for statistical significance when claiming evidence of new discoveries. Notwithstanding its potential impact, the proposal has motivated a large mass of authors to dispute it from different philosophical and methodological angles. This article reflects on the original argument and the consequent counterarguments, and concludes with a simpler and better-suited alternative that the authors of the proposal knew about and, perhaps, should have made from their Jeffresian perspective: to use a Bayes factors analysis in parallel (e.g., via JASP) in order to learn more about frequentist error statistics and about Bayesian prior and posterior beliefs without having to mix inconsistent research philosophies.

Black hole mass measurement in nearby galaxy using molecular gas dynamics

2016 ◽  
Author(s):  
Kyoko Onishi ◽  
Satoru Iguchi ◽  
Timothy Davis ◽  
Martin Bureau ◽  
Michele Cappellari ◽  
...  
Keyword(s):  
Black Hole ◽  
Gas Dynamics ◽  
Mass Measurement ◽  
Molecular Gas ◽  
Nearby Galaxy ◽  
Black Hole Mass
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