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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

FINDING FOSSIL GROUPS: OPTICAL IDENTIFICATION AND X-RAY CONFIRMATION

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Author(s):
Miller, Eric D. [1] ; Rykoff, Eli S. [2] ; Dupke, Renato A. [3, 4, 5] ; de Oliveira, Claudia Mendes [6] ; de Oliveira, Raimundo Lopes [7, 8] ; Proctor, Robert N. [6] ; Garmire, Gordon P. [9] ; Koester, Benjamin P. [10] ; McKay, Timothy A. [11]
Total Authors: 9
Affiliation:
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[1] MIT, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 - USA
[2] EO Lawrence Berkeley Natl Lab, Berkeley, CA 94720 - USA
[3] Eureka Sci Inc, Oakland, CA 94602 - USA
[4] Observ Nacl, BR-20921400 Rio De Janeiro, RJ - Brazil
[5] Univ Michigan, Dept Astron, Ann Arbor, MI 48109 - USA
[6] Univ Sao Paulo, Dept Astron, Inst Astron Geofis & Ciencias Atmosfericas, BR-05508090 Sao Paulo - Brazil
[7] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil
[8] Univ Fed Sergipe, Dept Fis, BR-49100000 Sao Cristovao, SE - Brazil
[9] Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 - USA
[10] Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 - USA
[11] Univ Michigan, Dept Phys, Ann Arbor, MI 48109 - USA
Total Affiliations: 11
Document type: Journal article
Source: ASTROPHYSICAL JOURNAL; v. 747, n. 2 MAR 10 2012.
Web of Science Citations: 21
Abstract

We report the discovery of 12 new fossil groups (FGs) of galaxies, systems dominated by a single giant elliptical galaxy and cluster-scale gravitational potential, but lacking the population of bright galaxies typically seen in galaxy clusters. These FGs, selected from the maxBCG optical cluster catalog, were detected in snapshot observations with the Chandra X-ray Observatory. We detail the highly successful selection method, with an 80% success rate in identifying 12 FGs from our target sample of 15 candidates. For 11 of the systems, we determine the X-ray luminosity, temperature, and hydrostatic mass, which do not deviate significantly from expectations for normal systems, spanning a range typical of rich groups and poor clusters of galaxies. A small number of detected FGs are morphologically irregular, possibly due to past mergers, interaction of the intra-group medium with a central active galactic nucleus (AGN), or superposition of multiple massive halos. Two-thirds of the X-ray-detected FGs exhibit X-ray emission associated with the central brightest cluster galaxy (BCG), although we are unable to distinguish between AGN and extended thermal galaxy emission using the current data. This sample representing a large increase in the number of known FGs, will be invaluable for future planned observations to determine FG temperature, gas density, metal abundance, and mass distributions, and to compare to normal (non-fossil) systems. Finally, the presence of a population of galaxy-poor systems may bias mass function determinations that measure richness from galaxy counts. When used to constrain power spectrum normalization and Omega(m), these biased mass functions may in turn bias these results. (AU)

FAPESP's process: 10/08341-3 - High energy astrophysics
Grantee:Raimundo Lopes de Oliveira Filho
Support type: Scholarships in Brazil - Young Researchers
FAPESP's process: 09/06295-7 - High energy astrophysics
Grantee:Raimundo Lopes de Oliveira Filho
Support type: Research Grants - Young Investigators Grants