The X‐Ray Surface Brightness Distribution from Diffuse Gas

2001 ◽  
Vol 556 (2) ◽  
pp. 590-600 ◽  
Author(s):  
Greg L. Bryan ◽  
G. Mark Voit
Keyword(s):  
Surface Brightness ◽  
Brightness Distribution ◽  
X Ray

scholarly journals The mergers in Abell 2256: displaced gas and its connection to the radio-emitting plasma

2020 ◽  
Vol 495 (4) ◽  
pp. 5014-5026 ◽  
Author(s):  
J P Breuer ◽  
N Werner ◽  
F Mernier ◽  
T Mroczkowski ◽  
A Simionescu ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Large Scale ◽  
Cold Front ◽  
Low Frequency ◽  
Brightness Distribution ◽  
Analytical Models ◽  
Line Of Sight ◽  
Cluster Galaxy ◽  
X Ray ◽  
Low Entropy

ABSTRACT We present the results of deep Chandra and XMM–Newton X-ray imaging and spatially resolved spectroscopy of Abell 2256, a nearby (z = 0.058) galaxy cluster experiencing multiple mergers and displaying a rich radio morphology dominated by a large relic. The X-ray data reveal three subclusters: (i) the ‘main cluster’; (ii) the remnant of an older merger in the east of the cluster with an ∼600 kpc-long tail; (iii) a bright, bullet-like, low-entropy infalling system, with a large line-of-sight velocity component. The low-entropy system displays a 250 kpc-long cold front with a break and an intriguing surface brightness decrement. Interestingly, the infalling gas is not co-spatial with bright galaxies and the radio-loud brightest cluster galaxy of the infalling group appears dissociated from the low-entropy plasma by ∼50 kpc in projection, to the south of the eastern edge of the cold front. Assuming that the dark matter follows the galaxy distribution, we predict that it is also significantly offset from the low-entropy gas. Part of the low-frequency radio emission near the cold front might be revived by magnetic field amplification due to differential gas motions. Using analytical models and numerical simulations, we investigate the possibility that the supersonic infall of the subcluster generates a large-scale shock along our line of sight, which can be detected in the X-ray temperature map but is not associated with any clear features in the surface brightness distribution.

scholarly journals Temperature Structure in Merging Coma Cluster of Galaxies

1998 ◽  
Vol 188 ◽  
pp. 308-309
Author(s):  
H. Honda ◽  
M. Hirayama ◽  
H. Ezawa ◽  
K. Kikuchi ◽  
T. Ohashi ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Brightness Distribution ◽  
Secondary Peak ◽  
Cluster Center ◽  
Temperature Structure ◽  
Coma Cluster ◽  
X Ray ◽  
Cluster Of Galaxies ◽  
The Galaxy ◽  
Complex Distribution

The Coma cluster has been recognized as an archetype of rich and relaxed clusters, until recent ROSAT observations reveal that the intracluster medium (ICM) has a complex distribution (Briel et al. 1992; White et al. 1993). The X-ray surface brightness distribution shows a secondary peak around the galaxy NGC 4839, at 40' SW from the cluster center.

Properties of the Surface Brightness Distribution of the Cosmic X-Ray Background

1990 ◽  
pp. 410-411
Author(s):  
G. De Zotti ◽  
A. Franceschini ◽  
M. Persic ◽  
L. Danese ◽  
E. A. Boldt ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Brightness Distribution ◽  
X Ray ◽  
X Ray Background

scholarly journals X-Ray Imaging Studies of NGC 1275 and The Core of The Perseus Cluster

1980 ◽  
Vol 5 ◽  
pp. 741-745
Author(s):  
J. Grindlay ◽  
G. Branduardi ◽  
A. Fabian
Keyword(s):  
Surface Brightness ◽  
Constant Pressure ◽  
Brightness Distribution ◽  
Imaging Studies ◽  
Cluster Emission ◽  
X Ray ◽  
The Core ◽  
X Ray Imaging ◽  
Ngc 1275 ◽  
Perseus Cluster

The EINSTEIN X-ray Observatory has been used to study the X-ray emission from the center of the Perseus cluster, including the active galaxy NGC 1275. Both a point source and extended (˜ 6’) source are observed from NGC 1275. The central 40’ × 40’ region of the Perseus cluster around NGC 1275 displays an interesting temperature and surface brightness distribution. Simple hydrostatic isothermal sphere models do not well describe the cluster emission. The surface brightness of the high resolution image of NGC 1275 can be fit with a constant-pressure but centrally-cooling (i.e., temperature increases with radius) gas which suggests a radiative cooling accretion flow onto NGC 1275.

scholarly journals Doppler Imaging of V404 Cyg in Quiescence

1996 ◽  
Vol 158 ◽  
pp. 395-398 ◽  
Author(s):  
Jorge Casares
Keyword(s):  
Mass Transfer ◽  
Black Hole ◽  
Surface Brightness ◽  
Hot Spot ◽  
Brightness Distribution ◽  
Accretion Disc ◽  
Doppler Imaging ◽  
X Ray ◽  
Secondary Star ◽  
Bright Spots

AbstractWe present Doppler images of the accretion disc in the black hole X-ray transient V404 Cyg during its quiescent phase. The Hα map shows evidence for a hot spot, indicating that mass transfer is continuing long after the 1989 outburst. Both the Hα and the IR Ca II emission maps exhibit intense bright spots at the position of the secondary star, which we take as a sign of chromospheric activity. The Ca II emission arises from the outer parts of the accretion disc, and its surface brightness distribution is consistent with dwarf novae discs (I∝R−3/2).

scholarly journals When Darwin Met Einstein: Gravitational Lens Inversion with Genetic Algorithms

2005 ◽  
Vol 22 (2) ◽  
pp. 128-135 ◽  
Author(s):  
Brendon J. Brewer ◽  
Geraint F. Lewis
Keyword(s):  
Genetic Algorithms ◽  
Gravitational Lensing ◽  
Surface Brightness ◽  
Initial Study ◽  
Brightness Distribution ◽  
Gravitational Lens ◽  
Atmospheric Effects ◽  
Lens Model ◽  
New Approach ◽  
Genetic Algorithm Approach

AbstractGravitational lensing can magnify a distant source, revealing structural detail which is normally unresolvable. Recovering this detail through an inversion of the influence of gravitational lensing, however, requires optimisation of not only lens parameters, but also of the surface brightness distribution of the source. This paper outlines a new approach to this inversion, utilising genetic algorithms to reconstruct the source profile. In this initial study, the effects of image degradation due to instrumental and atmospheric effects are neglected and it is assumed that the lens model is accurately known, but the genetic algorithm approach can be incorporated into more general optimisation techniques, allowing the optimisation of both the parameters for a lensing model and the surface brightness of the source.

scholarly journals An improved deprojection and PSF-deconvolution technique for galaxy-cluster X-ray surface-brightness profiles

2006 ◽  
Vol 459 (3) ◽  
pp. 1007-1019 ◽  
Author(s):  
J. H. Croston ◽  
M. Arnaud ◽  
E. Pointecouteau ◽  
G. W. Pratt
Keyword(s):  
Surface Brightness ◽  
Galaxy Cluster ◽  
X Ray ◽  
Deconvolution Technique

scholarly journals Figuring Out Gas & Galaxies In Enzo (FOGGIE). V. The Virial Temperature Does Not Describe Gas in a Virialized Galaxy Halo

2021 ◽  
Vol 922 (2) ◽  
pp. 121
Author(s):  
Cassandra Lochhaas ◽  
Jason Tumlinson ◽  
Brian W. O’Shea ◽  
Molly S. Peeples ◽  
Britton D. Smith ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Surface Brightness ◽  
Radiative Cooling ◽  
Low Density ◽  
Energy Partition ◽  
X Ray ◽  
Stellar Feedback ◽  
Galaxy Halo ◽  
Definition Of ◽  
Halo Gas

Abstract The classical definition of the virial temperature of a galaxy halo excludes a fundamental contribution to the energy partition of the halo: the kinetic energy of nonthermal gas motions. Using simulations of low-redshift, ∼L* galaxies from the Figuring Out Gas & Galaxies In Enzo (FOGGIE) project that are optimized to resolve low-density gas, we show that the kinetic energy of nonthermal motions is roughly equal to the energy of thermal motions. The simulated FOGGIE halos have ∼2× lower bulk temperatures than expected from a classical virial equilibrium, owing to significant nonthermal kinetic energy that is formally excluded from the definition of T vir. We explicitly derive a modified virial temperature including nonthermal gas motions that provides a more accurate description of gas temperatures for simulated halos in virial equilibrium. Strong bursts of stellar feedback drive the simulated FOGGIE halos out of virial equilibrium, but the halo gas cannot be accurately described by the standard virial temperature even when in virial equilibrium. Compared to the standard virial temperature, the cooler modified virial temperature implies other effects on halo gas: (i) the thermal gas pressure is lower, (ii) radiative cooling is more efficient, (iii) O vi absorbing gas that traces the virial temperature may be prevalent in halos of a higher mass than expected, (iv) gas mass estimates from X-ray surface brightness profiles may be incorrect, and (v) turbulent motions make an important contribution to the energy balance of a galaxy halo.

Sign in / Sign up

Export Citation Format

Share Document