scholarly journals X-raying the Hubble Frontier Fields cluster Abell 2744

2015 ◽  
Vol 11 (A29B) ◽  
pp. 760-763
Author(s):  
Dominique Eckert
Keyword(s):  
Dark Matter ◽  
Shock Front ◽  
Strong Evidence ◽  
Intergalactic Medium ◽  
Detailed Comparison ◽  
Cluster Core ◽  
X Ray ◽  
Thermodynamic Structure ◽  
Hot Gas ◽  
Luminous Matter

AbstractAbell 2744 was the first HFF cluster completed. It displays a fascinating complexity in its distribution of dark and luminous matter, which led to its nickname of the Pandora cluster. In late 2014 we obtained a deep (110 ks) observation of this cluster with XMM-Newton, with the aim of making a detailed comparison between the optical, X-ray and lensing properties of this system. The new X-ray observation unveiled the presence of three hot gas filaments extending on scales of several Mpc and connected to the cluster core. The X-ray structures coincide spatially with the distribution of galaxies and dark matter and provide strong evidence for the existence of the elusive warm-hot intergalactic medium (WHIM). The new observation also reveals the complexity of the thermodynamic structure of the cluster core and a probable shock front associated with the radio relic located 1 Mpc NW of the cluster core.

scholarly journals Detecting shocked intergalactic gas with X-ray and radio observations

2019 ◽  
Vol 627 ◽  
pp. A5 ◽  
Author(s):  
F. Vazza ◽  
S. Ettori ◽  
M. Roncarelli ◽  
M. Angelinelli ◽  
M. Brüggen ◽  
...  
Keyword(s):  
Large Scale ◽  
Intergalactic Medium ◽  
Thermal Emission ◽  
Intergalactic Gas ◽  
Radio Observations ◽  
X Ray ◽  
Large Scale Structures ◽  
Hot Gas ◽  
Scale Structures ◽  
Radio Band

Detecting the thermal and non-thermal emission from the shocked cosmic gas surrounding large-scale structures represents a challenge for observations, as well as a unique window into the physics of the warm-hot intergalactic medium. In this work, we present synthetic radio and X-ray surveys of large cosmological simulations in order to assess the chances of jointly detecting the cosmic web in both frequency ranges. We then propose best observing strategies tailored for existing (LOFAR, MWA, and XMM) or future instruments (SKA-LOW and SKA-MID, Athena, and eROSITA). We find that the most promising targets are the extreme peripheries of galaxy clusters in an early merging stage, where the merger causes the fast compression of warm-hot gas onto the virial region. By taking advantage of a detection in the radio band, future deep X-ray observations will probe this gas in emission, and help us to study plasma conditions in the dynamic warm-hot intergalactic medium with unprecedented detail.

scholarly journals Hot Gas in Groups and Their Galaxies

1998 ◽  
Vol 188 ◽  
pp. 61-64
Author(s):  
Trevor J. Ponman ◽  
Alexis Finoguenov
Keyword(s):  
Star Formation ◽  
Intergalactic Medium ◽  
Heavy Elements ◽  
X Ray ◽  
Hot Gas ◽  
Group Environment ◽  
Velocity Dispersions

It is clear that there is an important interplay between galaxies and the group environment. At the velocity dispersions (~ 100 km s−1) characteristic of groups, the galaxies interact strongly, leading to triggering of star formation, and galaxy merging. We can expect to see evidence of such processes through differences in the properties of galaxies in groups compared to field galaxies. Conversely, the galaxies affect their environment, as is apparent from the presence of heavy elements in the hot intergalactic medium (IGM) in groups, which emit characteristic X-ray lines.

scholarly journals Galaxies and the intergalactic medium in groups

2000 ◽  
Vol 174 ◽  
pp. 187-196
Author(s):  
Trevor J. Ponman ◽  
Ed Lloyd-Davies ◽  
Stephen F. Helsdon
Keyword(s):  
Galaxy Formation ◽  
Intergalactic Medium ◽  
Preliminary Evidence ◽  
Early Type ◽  
Present Evidence ◽  
X Ray ◽  
Hot Gas ◽  
Isolated Galaxies ◽  
The Relationship

AbstractThe study of the relationship between the hot gas in groups and the galaxies they contain can help to constrain the evolution of both galaxies and groups. Here we present evidence that the intergalactic medium in groups has been strongly affected by preheating associated with galaxy formation which mostly preceded group collapse. The presence of this effect appears to be unrelated to the morphology of group galaxies, which supports models in which galaxy types are not primordial. We also present preliminary evidence that early-type galaxies in groups are not underluminous in the X-ray compared to isolated galaxies, suggesting that their dark halos may not have been substantially stripped.

scholarly journals Dark matter and X-ray halo in early-type galaxies and clusters of galaxies

2009 ◽  
Vol 5 (H15) ◽  
pp. 89-90
Author(s):  
Takaya Ohashi
Keyword(s):  
Dark Matter ◽  
Clusters Of Galaxies ◽  
Large Scatter ◽  
Early Type ◽  
Matter Distribution ◽  
X Ray ◽  
Galaxy Groups ◽  
Hot Gas ◽  
Luminous Galaxies ◽  
Dark Matter Distribution

X-ray observations reveal extended halos around early-type galaxies which enable us to trace the dark matter distribution around the galaxies (see Mathews and Brighenti 2003 for a review). X-ray luminosities, LX of massive early-type galaxies are 1040−1042 erg s−1 in 0.3–2 keV. The correlation plot between LX and B-band luminosity LB shows a large scatter in the sense that LX varies by 2 orders of magnitudes for the same LB, in the brightest end (log LB ≳ 10.5). The amount of the X-ray hot gas in early-type galaxies is typically a few % of the stellar mass, in contrast to clusters of galaxies which hold ~5 times more massive gas than stars. Matsushita (2001) showed that X-ray luminous galaxies are characterized by extended X-ray halo with a few tens of re, similar to the scale of galaxy groups, so the presence of group-size potentials would be strongly linked with the problem of large LX scatter.

scholarly journals Investigating the Relationship Between the Hot Gas and the Dark Matter Components of Galaxy Clusters.

2007 ◽  
Vol 3 (S244) ◽  
pp. 374-375
Author(s):  
Leila C. Powell ◽  
Scott T. Kay ◽  
Arif Babul ◽  
Andisheh Mahdavi
Keyword(s):  
Dark Matter ◽  
Total Mass ◽  
Surface Brightness ◽  
Galaxy Cluster ◽  
Weak Lensing ◽  
X Ray ◽  
Hot Gas ◽  
Cluster Properties ◽  
The Impact ◽  
The Relationship

AbstractVarious differences in galaxy cluster properties derived from X-ray and weak lensing observations have been highlighted in the literature. One such difference is the observation of mass concentrations in lensing maps which have no X-ray counterparts (e.g. Jee, White, Ford et al. 2005). We investigate this issue by identifying substructures in maps of projected total mass (analogous to weak lensing mass reconstructions) and maps of projected X-ray surface brightness for three simulated clusters. We then compare the 2D mass substructures with both 3D subhalo data and the 2D X-ray substructures. Here we present preliminary results from the first comparison, where we have assessed the impact of projecting the data on subhalo identification.

scholarly journals The XXL Survey

2018 ◽  
Vol 620 ◽  
pp. A8 ◽  
Author(s):  
Arya Farahi ◽  
Valentina Guglielmo ◽  
August E. Evrard ◽  
Bianca M. Poggianti ◽  
Christophe Adami ◽  
...  
Keyword(s):  
Dark Matter ◽  
Velocity Dispersion ◽  
Gas Temperature ◽  
X Ray ◽  
Galaxy Groups ◽  
Hot Gas ◽  
Low Mass ◽  
Massive Halos ◽  
Weak Constraints ◽  
Velocity Bias

Context. An X-ray survey with the XMM-Newton telescope, XMM-XXL, has identified hundreds of galaxy groups and clusters in two 25 deg2 fields. Combining spectroscopic and X-ray observations in one field, we determine how the kinetic energy of galaxies scales with hot gas temperature and also, by imposing prior constraints on the relative energies of galaxies and dark matter, infer a power-law scaling of total mass with temperature. Aims. Our goals are: i) to determine parameters of the scaling between galaxy velocity dispersion and X-ray temperature, T300 kpc, for the halos hosting XXL-selected clusters, and; ii) to infer the log-mean scaling of total halo mass with temperature, ⟨lnM200 | T300 kpc, z⟩. Methods. We applied an ensemble velocity likelihood to a sample of >1500 spectroscopic redshifts within 132 spectroscopically confirmed clusters with redshifts z < 0.6 to model, ⟨lnσgal | T300 kpc, z⟩, where σgal is the velocity dispersion of XXL cluster member galaxies and T300 kpc is a 300 kpc aperture temperature. To infer total halo mass we used a precise virial relation for massive halos calibrated by N-body simulations along with a single degree of freedom summarising galaxy velocity bias with respect to dark matter. Results. For the XXL-N cluster sample, we find σgal ∝ T300 kpc0.63±0.05, a slope significantly steeper than the self-similar expectation of 0.5. Assuming scale-independent galaxy velocity bias, we infer a mean logarithmic mass at a given X-ray temperature and redshift, 〈ln(E(z)M200/1014 M⊙)|T300 kpc, z〉 = πT + αT ln (T300 kpc/Tp) + βT ln (E(z)/E(zp)) using pivot values kTp = 2.2 keV and zp = 0.25, with normalization πT = 0.45 ± 0.24 and slope αT = 1.89 ± 0.15. We obtain only weak constraints on redshift evolution, βT = −1.29 ± 1.14. Conclusions. The ratio of specific energies in hot gas and galaxies is scale dependent. Ensemble spectroscopic analysis is a viable method to infer mean scaling relations, particularly for the numerous low mass systems with small numbers of spectroscopic members per system. Galaxy velocity bias is the dominant systematic uncertainty in dynamical mass estimates.

scholarly journals FM 22. Mapping the Frontier Fields with Chandra X-ray Observations

2015 ◽  
Vol 11 (A29B) ◽  
pp. 758-759
Author(s):  
C. Jones ◽  
R. van Weeren ◽  
G. Ogrean ◽  
W. Forman
Keyword(s):  
Dark Matter ◽  
High Resolution ◽  
X Ray ◽  
Hot Gas ◽  
Cold Fronts ◽  
Dynamical State ◽  
Cluster Morphology ◽  
Cluster Mergers ◽  
Relativistic Particles ◽  
Resolution Mass

AbstractChandra has deeply observed the clusters and parallel fields in four Frontier Fields. These observations allow us to dramatically improve our understanding of cluster mergers by comparing the detailed mapping of the hot cluster gas with high resolution mass maps and by identifying merger shocks and cold fronts. In merging clusters, relativistic particles can be re-accelerated to produce radio relics. A comparison of lensing maps and Chandra images allows us to determine the cluster morphology and dynamical state and if there are offsets between the dark matter and the hot gas.

scholarly journals The impact of the observed baryon distribution in haloes on the total matter power spectrum

2019 ◽  
Vol 492 (2) ◽  
pp. 2285-2307 ◽  
Author(s):  
Stijn N B Debackere ◽  
Joop Schaye ◽  
Henk Hoekstra
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Gas Content ◽  
Total Power ◽  
X Ray ◽  
Hot Gas ◽  
Matter Power Spectrum ◽  
Hydrodynamical Simulations ◽  
Halo Masses ◽  
The Impact

ABSTRACT The interpretation of upcoming weak gravitational lensing surveys depends critically on our understanding of the matter power spectrum on scales $k \lt 10\, {h\, {\rm Mpc}^{-1}}$, where baryonic processes are important. We study the impact of galaxy formation processes on the matter power spectrum using a halo model that treats the stars and gas separately from the dark matter distribution. We use empirical constraints from X-ray observations (hot gas) and halo occupation distribution modelling (stars) for the baryons. Since X-ray observations cannot generally measure the hot gas content outside r500c, we vary the gas density profiles beyond this radius. Compared with dark matter only models, we find a total power suppression of $1\, {\mathrm{per\ cent}}$ ($5\, {\mathrm{per\ cent}}$) on scales $0.2\!-\!1\, {h\, {\rm Mpc}^{-1}}$ ($0.5\!-\!2\, {h\, {\rm Mpc}^{-1}}$), where lower baryon fractions result in stronger suppression. We show that groups of galaxies ($10^{13} \lt m_{\mathrm{500c}} / (h^{-1}\, \mathrm{M}_{\odot }) \lt 10^{14}$) dominate the total power at all scales $k \lesssim 10\, {h\, {\rm Mpc}^{-1}}$. We find that a halo mass bias of $30\, {\mathrm{per\ cent}}$ (similar to what is expected from the hydrostatic equilibrium assumption) results in an underestimation of the power suppression of up to $4\, {\mathrm{per\ cent}}$ at $k=1\, {h\, {\rm Mpc}^{-1}}$, illustrating the importance of measuring accurate halo masses. Contrary to work based on hydrodynamical simulations, our conclusion that baryonic effects can no longer be neglected is not subject to uncertainties associated with our poor understanding of feedback processes. Observationally, probing the outskirts of groups and clusters will provide the tightest constraints on the power suppression for $k \lesssim 1\, {h\, {\rm Mpc}^{-1}}$.

scholarly journals Hot gas in the cold dark matter scenario: X-ray clusters from a high-resolution numerical simulation

1994 ◽  
Vol 428 ◽  
pp. 1 ◽  
Author(s):  
Hyesung Kang ◽  
Renyue Cen ◽  
Jeremiah P. Ostriker ◽  
Dongsu Ryu
Keyword(s):  
Numerical Simulation ◽  
Dark Matter ◽  
High Resolution ◽  
Cold Dark Matter ◽  
X Ray ◽  
Hot Gas
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