Chandrameasurements of a complete sample of X-ray luminous galaxy clusters: the luminosity–mass relation

The Rosat All-Sky Survey (Trümper 1991, Adv. Spce Res., 2, 241) has its largest exposure times, approaching 10 ks, at the ecliptic poles where the scan circles overlap. The North Ecliptic Pole (NEP) region covers a 9° X 9° field, and contains a total of 465 X-ray sources detected at > 4σ in the 0.1-2.4 keV. We are identifying all sources in the field. The principal derivative is a statistically complete sample of galaxy clusters appropriate for more fully characterizing X-ray Luminosity Function (XLF) evolution. We report preliminary results for two subregions which are identified to the 95% level. These subregions are observed to approximately the median NEP survey exposure. They enclose 16% of the survey area and contain 96 X-ray sources representing 21% of the total NEP. The typical mix of sources is consistent with the Einstein Extended Medium Sensisitivity Survey (EMSS; Gioia et al., 1990a, ApJS, 72, 567). In particular there are 56% AGN/ELG (59% in the EMSS), 25% stars (27% in the EMSS) and 14% clusters against 13% clusters in the EMSS.

Download Full-text

Chandra measurements of a complete sample of X-ray luminous galaxy clusters: the gas mass fraction

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stt901 ◽

2013 ◽

Vol 433 (4) ◽

pp. 2790-2811 ◽

Cited By ~ 28

Author(s):

D. Landry ◽

M. Bonamente ◽

P. Giles ◽

B. Maughan ◽

M. Joy ◽

...

Keyword(s):

Galaxy Clusters ◽

Mass Fraction ◽

Complete Sample ◽

X Ray

Download Full-text

Diffuse radio sources in a statistically complete sample of high-redshift galaxy clusters

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038263 ◽

2020 ◽

Vol 640 ◽

pp. A108 ◽

Cited By ~ 1

Author(s):

G. Giovannini ◽

M. Cau ◽

A. Bonafede ◽

H. Ebeling ◽

L. Feretti ◽

...

Keyword(s):

Radio Emission ◽

Galaxy Clusters ◽

High Redshift ◽

Complete Sample ◽

Cluster Emission ◽

X Ray ◽

Cluster Galaxies ◽

Diffuse Sources ◽

Radio Halo ◽

Radio Halos

Aims. Non-thermal properties of galaxy clusters have been studied using detailed and deep radio images in comparison with X-ray data. While much progress has been made in this area, most of the studied clusters are at a relatively low redshift (z < 0.3). Here we investigate the evolutionary properties of the non-thermal cluster emission using two statistically complete samples at z > 0.3. Methods. We obtained short JVLA observations at the L-band of the statistically complete sample of very X-ray luminous clusters from the Massive Cluster Survey (MACS), namely 34 clusters in the redshift range of 0.3–0.5 and with nominal X-ray fluxes in excess of 2 × 10−12 erg s−1 cm−2 (0.1–2.4 keV) in the ROSAT Bright Source Catalogue. We add to this list the complete sample of the 12 most distant MACS clusters (z > 0.5). Results. Most clusters show evidence of emission in the radio regime. We present the radio properties of all clusters in our sample and show images of newly detected diffuse sources. A radio halo is detected in 19 clusters and five clusters contain a relic source. Most of the brightest cluster galaxies (BCG) in relaxed clusters show radio emission with powers typical of FRII radio galaxies and some are surrounded by a radio mini-halo. Conclusions. The high frequency of radio emission from the BCG in relaxed clusters suggests that BCG feedback mechanisms are already in place at z ∼ 0.6. The properties of radio halos and the small number of detected relics suggest redshift evolution in the properties of diffuse sources. The radio power (and size) of radio halos could be related to the number of past merger events in the history of the system. In this scenario, the presence of a giant and high-power radio halo is indicative of an evolved system with a large number of past major mergers, whereas small low-power halos are found in less evolved clusters.

Download Full-text

High redshift X-ray galaxy clusters

Astronomy and Astrophysics ◽

10.1051/0004-6361:20077467 ◽

2007 ◽

Vol 472 (3) ◽

pp. 739-748 ◽

Cited By ~ 28

Author(s):

M. Branchesi ◽

I. M. Gioia ◽

C. Fanti ◽

R. Fanti

Keyword(s):

Galaxy Clusters ◽

High Redshift ◽

X Ray

Download Full-text

Clustering dependence of Chandra COSMOS Legacy AGN on host galaxy properties

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320002987 ◽

2019 ◽

Vol 15 (S356) ◽

pp. 226-226

Author(s):

Viola Allevato

Keyword(s):

Dark Matter ◽

Formation Rate ◽

Stellar Mass ◽

Active Galaxies ◽

Host Galaxy ◽

Mass Star ◽

Mass Relation ◽

Dark Matter Halos ◽

X Ray

AbstractThe presence of a super massive BH in almost all galaxies in the Universe is an accepted paradigm in astronomy. How these BHs form and how they co-evolve with the host galaxy is one of the most intriguing unanswered problems in modern Cosmology and of extreme relevance to understand the issue of galaxy formation. Clustering measurements can powerfully test theoretical model predictions of BH triggering scenarios and put constraints on the typical environment where AGN live in, through the connection with their host dark matter halos. In this talk, I will present some recent results on the AGN clustering dependence on host galaxy properties, such as galaxy stellar mass, star formation rate and specific BH accretion rate, based on X-ray selected Chandra COSMOS Legacy Type 2 AGN. We found no significant AGN clustering dependence on galaxy stellar mass and specif BHAR for Type 2 COSMOS AGN at mean z ∼ 1.1, with a stellar - halo mass relation flatter than predicted for non active galaxies in the Mstar range probed by our sample. We also observed a negative clustering dependence on SFR, with AGN hosting halo mass increasing with decreasing SFR. Mock catalogs of active galaxies in hosting dark matter halos with logMh[Msun] > 12.5, matched to have the same X-ray luminosity, stellar mass and BHAR of COSMOS AGN predict the observed Mstar - Mh, BHAR - Mh and SFR-Mh relations, at z ∼ 1.

Download Full-text