THE ROADMAP FOR UNIFICATION IN GALAXY GROUP SELECTION. I. A SEARCH FOR EXTENDED X-RAY EMISSION IN THE CNOC2 SURVEY

Journal Article · Sat Oct 10 04:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/704/1/564· OSTI ID:21367438

Finoguenov, A; Connelly, J L; Wilman, D J; Saglia, R P ^[1]; Parker, L C ^[2]; Mulchaey, J S ^[3]; Balogh, M L; McGee, S L ^[4]; Bower, R G ^[5]

---

1. Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse, 85748 Garching (Germany)
2. Department of Physics and Astronomy, McMaster University, 1280 Main St. W, Hamilton, ON L8S 4M1 (Canada)
3. The Observatories of the Carnegie Institution of Washington, Pasadena, CA (United States)
4. Department of Physics and Astronomy, University of Waterloo, 200 University Avenue, Waterloo, ON N2L 3G1 (Canada)
5. Institute for Computational Cosmology, University of Durham, Durham (United Kingdom)

X-ray properties of galaxy groups can unlock some of the most challenging research topics in modern extragalactic astronomy: the growth of structure and its influence on galaxy formation. Only with the advent of the Chandra and XMM-Newton facilities have X-ray observations reached the depths required to address these questions in a satisfactory manner. Here we present an X-ray imaging study of two patches from the CNOC2 spectroscopic galaxy survey using combined Chandra and XMM-Newton data. A state of the art extended source finding algorithm has been applied, and the resultant source catalog, including redshifts from a spectroscopic follow-up program, is presented. The total number of spectroscopically identified groups is 25 spanning a redshift range 0.04-0.79. Approximately 50% of CNOC2 spectroscopically selected groups in the deeper X-ray (RA14h) field are likely X-ray detections, compared to 20% in the shallower (RA21h) field. Statistical modeling shows that this is consistent with expectations, assuming an expected evolution of the L{sub X} -M relation. A significant detection of a stacked shear signal for both spectroscopic and X-ray groups indicates that both samples contain real groups of about the expected mass. We conclude that the current area and depth of X-ray and spectroscopic facilities provide a unique window of opportunity at z approx 0.4 to test the X-ray appearance of galaxy groups selected in various ways. There is at present no evidence that the correlation between X-ray luminosity and velocity dispersion evolves significantly with redshift, which implies that catalogs based on either method can be fairly compared and modeled.

• OSTI ID: 21367438
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 704; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ALGORITHMS
ASTRONOMY
CATALOGS
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
COSMOLOGY
DETECTION
DOCUMENT TYPES
EMISSION
GALAXIES
GALAXY CLUSTERS
LUMINOSITY
MATHEMATICAL LOGIC
MATTER
NONLUMINOUS MATTER
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATION DETECTION
RED SHIFT
SIGNALS
SIMULATION
VELOCITY
X-RAY DETECTION
X-RAY GALAXIES