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We use three-dimensional high-resolution adaptive-mesh-refinement simulations to investigate if mechanical feedback from active galactic nucleus jets can halt a massive cooling flow in a galaxy cluster and give rise to a self-regulated…

Astrophysics · Physics 2008-11-26 A. Cattaneo , R. Teyssier

Mass accretion rate is a key parameter in accretion disk theory. It determines black hole accretion mode. In large scale cosmological simulations studying galaxy formation and evolution, Bondi radius can at most be marginally resolved. In…

High Energy Astrophysical Phenomena · Physics 2019-01-30 De-Fu Bu , Xiao-Hong Yang

We investigate the accretion-driven growth of supermassive black holes in the low-redshift Universe using 23,000 ``Type 2'' AGN and the complete sample of 123,000 galaxies in the SDSS from which they were drawn. We use the stellar velocity…

We present the first observational constraint on the Br-gamma recombination line emission associated with the supermassive black hole at the center of our Galaxy, known as Sgr A*. By combining 13 years of data with the Adaptive Optics fed…

Astrophysics of Galaxies · Physics 2021-04-12 Anna Ciurlo , Mark R. Morris , Randall D. Campbell , Andrea M. Ghez , Tuan Do , Devin S. Chu

(Abridged) We propose a new method to estimate the Bondi (hot gas) accretion rates, \dot M_B, onto the supermassive black holes (SMBHs) at the centres of elliptical galaxies. It can be applied even if the Bondi radius is not well-resolved…

High Energy Astrophysical Phenomena · Physics 2016-01-19 Yutaka Fujita , Nozomu Kawakatu , Isaac Shlosman

(Abridged) We investigate non-spherical behavior of gas accreting onto a central supermassive black hole performing simulations using the SPH code GADGET-3 including radiative cooling and heating by the central X-ray source. As found in…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-13 Paramita Barai , Daniel Proga , Kentaro Nagamine

Accretion disks around active galactic nuclei are potentially unstable to star formation at large radii. We note that when the compact objects formed from some of these stars spiral into the central supermassive black hole, there is no…

High Energy Astrophysical Phenomena · Physics 2020-02-26 Alexander J. Dittmann , M. Coleman Miller

We studied the accretion disc structure in the doubly imaged lensed quasar SDSS J1339+1310 using $r$-band light curves and UV-visible to near-IR (NIR) spectra from the first 11 observational seasons after its discovery. The 2009$-$2019…

Astrophysics of Galaxies · Physics 2021-02-24 V. N. Shalyapin , L. J. Goicoechea , C. W. Morgan , M. A. Cornachione , A. V. Sergeyev

We analyze 134 ks Chandra ACIS-I observations of the Galactic Centre (GC) performed in July 2011. The X-ray image with the field of view $17' \times 17'$ contains the hot plasma surrounding the Sgr~A*. The obtained surface brightness map…

High Energy Astrophysical Phenomena · Physics 2015-09-09 A. Rozanska , P. Mroz , M. Moscibrodzka , M. Sobolewska , T. P. Adhikari

The radio source Sagittarius A* (Sgr A*) is believed to be a hot, inhomogeneous, magnetized plasma flowing near the event horizon of the 3 million solar mass black hole at the galactic center. At a distance of 8000 parsecs the black hole…

Astrophysics · Physics 2008-11-26 Scott C. Noble , Po Kin Leung , Charles F. Gammie , Laura G. Book

We present 1-second cadence observations of M32 (NGC221) with the CHIMERA instrument at the Hale 200-inch telescope of the Palomar Observatory. Using field stars as a baseline for relative photometry, we are able to construct a light curve…

Astrophysics of Galaxies · Physics 2017-05-03 R. Chary , G. Hallinan , L. K. Harding , N. S. Saini , H. E. Schlichting

We argue that one of the basic assumptions of the Bondi accretion process, that the accreting object has zero pressure, might not hold in many galaxies because of the pressure exerted by stellar winds of star orbiting the central super…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Shlomi Hillel , Noam Soker

Sub milli-arcsecond astrometry and imaging of the black hole Sgr A* at the Galactic centre may become possible in the near future at infrared and sub-millimetre wavelengths. Motivated by observations of short-term infrared and X-ray…

Astrophysics · Physics 2009-11-13 Avery E. Broderick , Abraham Loeb

We present numerical simulations of stellar wind dynamics in the central parsec of the Galactic centre, studying in particular the accretion of gas on to Sgr A*, the super-massive black hole. Unlike our previous work, here we use…

Astrophysics · Physics 2009-03-08 Jorge Cuadra , Sergei Nayakshin , Fabrice Martins

We perform global three-dimensional (3D) radiation-hydrodynamic (RHD) simulations of out- flow from supercritical accretion flow around a 10 Msun black hole. We only solve the outflow part, starting from the axisymmetric 2D simulation data…

High Energy Astrophysical Phenomena · Physics 2018-02-28 Hiroshi Kobayashi , Ken Ohsuga , Hiroyuki R. Takahashi , Tomohisa Kawashima , Yuta Asahina , Shun Takeuchi , Shin Mineshige

The collapse of baryons into extremely massive stars with masses exceeding 10^4 M_Sun in a small fraction of protogalaxies at z > 10 is a promising candidate for the origin of supermassive black holes, some of which grow to a billion solar…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Jarrett L. Johnson , Daniel J. Whalen , Christopher L. Fryer , Hui Li

It is commonly believed that the optical/UV and X-ray emissions in luminous AGN are produced in an accretion disk and an embedded hot corona respectively. The inverse Compton scattering of disk photons by hot electrons in the corona can…

High Energy Astrophysical Phenomena · Physics 2015-05-05 B. F. Liu , R. E. Taam , E. Qiao , W. Yuan

The inner few parsecs at the Galactic Center have come under intense scrutiny in recent years, in part due to the exciting broad-band observations of this region, but also because of the growing interest from theorists motivated to study…

Astrophysics · Physics 2009-11-06 Fulvio Melia , Heino Falcke

We model the spectral energy distribution of the type 1 Seyfert galaxy NGC 5548, fitting data from simultaneous optical, UV, and X-ray monitoring observations. We assume a geometry consisting of a hot central Comptonizing region surrounded…

Astrophysics · Physics 2009-11-07 James Chiang , Omer Blaes

Proposed scaling relations of a characteristic timescale in the X-ray power spectral density of galactic and supermassive black holes have been used to argue that the accretion process is the same for small and large black holes. Here, we…

Astrophysics of Galaxies · Physics 2009-11-13 L. Meyer , T. Do , A. Ghez , M. R. Morris , S. Yelda , R. Schoedel , A. Eckart