scholarly journals ASCA Observation of Groups of Galaxies

1998 ◽  
Vol 188 ◽  
pp. 327-328 ◽  
Author(s):  
Y. Tawara ◽  
S. Sato ◽  
A. Furuzawa ◽  
K. Yamashita ◽  
K. Isobe ◽  
...  
Keyword(s):  
Spectral Properties ◽  
Abundance Ratio ◽  
Compact Groups ◽  
Cool Component ◽  
X Ray ◽  
Groups Of Galaxies

Based on the ASCA observations, the X-ray features like spatial extentions and spectral properties of their component were analyzed for nearby four compact groups of galaxies; HCG62, NGC2300 group, HCG42 and HCG48. We found wide variety in their X-ray features. One of the brightest source of HCG62 shows the presence of cool component and enhanced abundance at its center, while HCG42 shows less extention and low abundance ratio of α-element to iron. For NGC 2300 group, we also found interesting feature which may be related to galaxy-intragroup medium interaction.

X-ray emission from compact groups of galaxies

1980 ◽  
Vol 238 ◽  
pp. L59 ◽  
Author(s):  
D. A. Schwartz ◽  
J. Schwarz ◽  
W. Tucker
Keyword(s):  
Compact Groups ◽  
X Ray ◽  
Groups Of Galaxies

X-ray emission from Hickson's compact groups of galaxies: Results from the ROSAT All-Sky Survey

1994 ◽  
Vol 436 ◽  
pp. 44 ◽  
Author(s):  
Harald Ebeling ◽  
Wolfgang Voges ◽  
Hans Boehringer
Keyword(s):  
Compact Groups ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Sky Survey

scholarly journals Intragroup Gas in Differently Evolved Compact Groups of Galaxies

2006 ◽  
Vol 2 (S235) ◽  
pp. 221-221
Author(s):  
L. Verdes-Montenegro ◽  
J. Rasmussen ◽  
T. Ponman ◽  
M. S. Yun ◽  
S. Borthakur
Keyword(s):  
Star Formation ◽  
Detection Rate ◽  
Virgo Cluster ◽  
Radio Continuum ◽  
Continuum Emission ◽  
Compact Groups ◽  
Evolutionary Status ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Star Formation Activity

AbstractCompact groups are highly isolated, dense galaxy systems, and therefore tidal interactions are expected to be continuous and dynamically important. For this reason they represent unique laboratories for studying interactions in extreme environments and tidally induced star formation as well as morphological and dynamical evolution of galaxies in general. This study is part of a broader investigation of the evolutionary status of HCGs. In order to explain the HI deficiency found in compact groups of galaxies we have proposed a broad evolutionary scenario in which the amount of HI decreases with the secular evolutionary state of a group. The fate of this gas is however not clear. In order to investigate the physical mechanisms responsible for these changes in the gas content of galaxies we have started a study to look for an intragroup medium (IGM). We have considered this IGM to be neutral (see e.g. reports of HI clouds within Virgo cluster (Oosterloo & Van Gorkom 2005), or hot gas (a higher X-ray detection rate of HI deficient groups is found relative to groups with a normal HI content, Verdes-Montenegro et al. 2001). Enhanced star formation activity might also be contributing to exhausting the gas supply. We have observed 25 HCGs with diverse HI content and distribution with the Green Bank radiotelescope, and performed VLA-HI as well as X-ray (XMM or Chandra) observations of the most HI deficient groups HCG 7, 15, 30, 37, 40, 44 and 97. We have also analysed FIR data from Verdes-Montenegro et al. (1998).Our results are: (a) HI deficient groups show a larger amount of diffuse neutral and X-ray gas when compared to non-deficient ones, consistent with our evolutionary picture; (b) Most groups are still deficient after including diffuse gas. (c) A hot IGM is not detected in most of these systems, but the detection rate is higher for the high velocity dispersion groups, and in these cases ram pressure stripping could potentially cause the observed HI-deficiency. (d) In several of these groups we detect intragroup radio continuum emission, which is surprising since similar features were seen previously only in massive clusters (known as “relic” sources). (e) Star formation activity traced by FIR luminosity is not enhanced, contrary to the general expectation of tidally interacting systems.Hence neither the presence of a hot or cold IGM nor star formation activity seem to be able to uniquely explain the HI deficiency found in compact groups of galaxies. We plan to explore the possibility that earlier starbursts could have contributed to the present HI deficiency.

scholarly journals Observational Properties of the Shakhbazian Groups SHKH 30 and SHKH 360

1994 ◽  
Vol 161 ◽  
pp. 623-625
Author(s):  
H. Tiersch ◽  
H. Oleak ◽  
D. Stoll ◽  
H. Böhringer
Keyword(s):  
Compact Groups ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Sky Survey

X-ray emission has been detected from 12 compact groups of galaxies of the Shakhbazian catalogue (out of 27 investigated groups) with the ROSAT PSPC all-sky survey. The groups Shkh 30 (Shakhbazian 1973) and Shkh 360 (Petrosian 1978) are presented here (Figs. 1 and 2).

scholarly journals Fossil groups of galaxies: Are they groups? Are they fossils?

2009 ◽  
Vol 5 (H15) ◽  
pp. 287-287 ◽  
Author(s):  
Renato de Alencar Dupke ◽  
Eric Miller ◽  
Claudia Mendes de Oliveira ◽  
Laerte Sodre ◽  
Eli Rykoff ◽  
...  
Keyword(s):  
Mass Fraction ◽  
Abundance Ratio ◽  
Measured Concentration ◽  
Potential Wells ◽  
X Ray ◽  
Groups Of Galaxies ◽  
The Core ◽  
Central Galaxy ◽  
Central Regions ◽  
Metal Abundance

AbstractFossil groups present a puzzle to current theories of structure formation. Despite the low number of bright galaxies, their high velocity dispersions and high TX indicate cluster-like potential wells. Measured concentration parameters seem very high indicating early formation epochs in contradiction with the observed lack of large and well defined cooling cores. There are very few fossil groups with good quality X-ray data and their idiosyncrasies may enhance these apparent contradictions. The standard explanation for their formation suggests that bright galaxies within half the virial radii of these systems were wiped out by cannibalism forming the central galaxy. Since dry mergers, typically invoked to explain the formation of the central galaxies, are not expected to change the IGM energetics significantly, thus not preventing the formation of cooling cores, we investigate the scenario where recent gaseous (wet) mergers formed the central galaxy injecting energy and changing the chemistry of the IGM in fossil groups. We show a test for this scenario using fossil groups with enough X-ray flux in the Chandra X-ray Observatory archive by looking at individual metal abundance ratio distributions near the core. Secondary SN II powered winds would tend to erase the dominance of SN IA ejecta in the core of these systems and would help to erase previously existing cold cores. Strong SN II-powered galactic winds resulting from galaxy merging would be trapped by their deep potential wells reducing the central enhancement of SN Ia/SN II iron mass fraction ratio. The results indicate that there is a decrement in the ratio of SN Ia to SN II iron mass fraction in the central regions of the systems analyzed, varying from 99±1% in the outer regions to 85±2% within the cooling radius (Figure 1) and would inject enough energy into the IGM preventing central gas cooling. The results are consistent with a scenario of later formation epoch for fossil groups, as they are defined, when compared to galaxy clusters and normal groups.

The Formation of Compact Groups of Galaxies. II. X-Ray Properties

1995 ◽  
Vol 109 ◽  
pp. 2293 ◽  
Author(s):  
Antonaldo Diaferio ◽  
Margaret J. Geller ◽  
Massimo Ramella
Keyword(s):  
Compact Groups ◽  
X Ray ◽  
Groups Of Galaxies

scholarly journals SOME LIKE IT HOT: LINKING DIFFUSE X-RAY LUMINOSITY, BARYONIC MASS, AND STAR FORMATION RATE IN COMPACT GROUPS OF GALAXIES

2014 ◽  
Vol 790 (2) ◽  
pp. 132 ◽  
Author(s):  
Tyler D. Desjardins ◽  
Sarah C. Gallagher ◽  
Ann E. Hornschemeier ◽  
John S. Mulchaey ◽  
Lisa May Walker ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Compact Groups ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Baryonic Mass

scholarly journals The Origin of Intergalactic Light in Compact Groups of Galaxies

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 303
Author(s):  
Mark J. Henriksen
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
High Mass ◽  
Compact Groups ◽  
Source Population ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Evolutionary Phase ◽  
X Ray Binaries ◽  
Lower Luminosity

We investigate the origin of intergalactic light (IGL) in close groups of galaxies. IGL is hypothesized to be the byproduct of interaction and merger within compact groups. Comparing the X-ray point source population in our sample of compact groups that have intergalactic light with compact groups without IGL, we find marginal evidence for a small increase in ultra-luminous X-ray sources (ULXs). There is also a significant bias towards lower luminosity high mass X-ray binaries (HMXRBs). We interpret this as an indication that groups with visible IGL represent a later evolutionary phase than other compact groups. They have galaxies characterized by quenching of star formation (lower star formation rate (SFR) inferred from lower HMXRB luminosity) after stellar material has been removed from the galaxies into the intergalactic medium, which is the source of the IGL. We conclude that the presence of an increased fraction of ULXs is due to past interaction and mergers within groups that have IGL.

scholarly journals The Hercules cluster in X-rays with XMM-Newton and Chandra

2020 ◽  
Vol 500 (4) ◽  
pp. 5524-5542
Author(s):  
Juhi Tiwari ◽  
Kulinder Pal Singh
Keyword(s):  
Elemental Abundance ◽  
Compact Groups ◽  
X Rays ◽  
The West ◽  
Bimodal Structure ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Average Temperature ◽  
Hot Gas ◽  
Ram Pressure

ABSTRACT We present a detailed X-ray study of the central subcluster of the nearby ($z\, \sim$0.0368) Hercules cluster (Abell 2151) identified as A2151C that shows a bimodal structure. A bright clump of hot gas with X-ray emission extending to radius $r\, \sim$304 kpc and $L_X = 3.03_{-0.04}^{+0.02}\times 10^{43}$ erg s−1 in the 0.4–7.0 keV energy range is seen as a fairly regular subclump towards the west (A2151C(B)). An irregular, fainter and cooler subclump with radius $r\, \sim$364 kpc is seen towards the east (A2151C(F)) and has LX = 1.13 ± 0.02 × 1043 erg s−1 in the 0.4–7.0 keV energy band. The average temperature and elemental abundance of A2151C(B) are 2.01 ± 0.05 keV and 0.43 ± 0.05 Z⊙, respectively, while these values are 1.17 ± 0.04 keV and 0.13 ± 0.02 Z⊙ for A2151C(F). Low temperature (1.55 ± 0.07 keV) and a short cooling time (∼0.81 Gyr) within the central 15 arcsec region confirm the presence of a cool core in A2151C(B). We identify several compact groups of galaxies within A2151C(F). We find that A2151C(F) is a distinct galaxy group in the process of formation and likely not a ram-pressure stripped part of the eastern subcluster in Hercules (A2151E). X-ray emission from A2151C shows a region of overlap between A2151C(B) and A2151C(F) but without any enhancement of temperature or entropy in the two-dimensional (2D) projected thermodynamic maps that could have indicated an interaction due to a merger between the two subclumps.

scholarly journals Compact and Fossil Groups

2006 ◽  
Vol 2 (S235) ◽  
pp. 160-164
Author(s):  
Claudia Mendes de Oliveira ◽  
Philippe Amram
Keyword(s):  
Elliptical Galaxy ◽  
Short Review ◽  
Compact Groups ◽  
X Ray ◽  
Groups Of Galaxies ◽  
End Products

AbstractWe present a short review on poor groups of galaxies focusing on the evolution of compact groups and formation of fossil groups. Fossil groups are systems with one dominant luminous elliptical galaxy surrounded by faint companions, in an extended X-ray halo. We will briefly discuss the possibility of fossil groups being the end-products of the merging of compact groups.

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