Searching for X-ray luminous 'normal' galaxies in 2dfGRS

Abstract

We cross-correlated the Chandra XASSIST and XMM-Newton Serendipitous Source Catalogues with the 2 degree Field Galaxy Redshift Survey (2dfGRS) database. Our aim was to identify the most X-ray luminous (L_X > 10^42 erg s^-1) examples of galaxies in the local Universe whose X-ray emission is dominated by stellar processes rather than AGN activity ('normal' galaxies) as well as to test the empirical criterion log(f_X/f_O) < -2 for separating AGN from NGs. With XMM-Newton (Chandra) we covered an area of ~8.2 (~5.8)deg^2 down to a flux limit of ~10^-15 (~1.6 x 10^-15) erg cm^-2 s^-1 and found 18 (20) 2dfGRS galaxies. Using emission-line intensity ratios, we classified 6 2dfGRS spectra as star-forming, H II nuclei, and 2 spectra as possible H II nuclei. The rest of the objects are absorption-line galaxies and AGN, including 3 possible LINERs. No luminous 'normal' galaxies have been found but out of 19 'normal' galaxies in this sample 5 H II and 3 absorption-line galaxies have log(f_X/f_O) > -2. We performed a similar search in two nearby-galaxy samples from the literature. All 44 galaxies in the Zezas (2001) sample have log(f_X/f_O) < -2 and L_X < 10^42 erg s^-1. In the Fabbiano et al. (1992) sample, out of a total of 170 'normal' galaxies, we found 16 galaxies with log(f_X/f_O) >-2, the majority of which are massive ellipticals. Three of these have L_X > 10^42 erg s^-1 .

8 pages, 2 figures. Accepted for publication in Astronomy & Astrophysics

References in corpus (19)

• The 2dF Galaxy Redshift Survey: Spectra and redshifts
• A Search for "Dwarf" Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies
• The Chandra Deep Field-North Survey. XIII. 2 Ms Point-Source Catalogs
• The Chandra Deep Field South: the 1 Million Second
• The 2dF Galaxy Redshift Survey: The b_J-band galaxy luminosity function and survey selection function
• Low mass X-ray binaries as a stellar mass indicator for the host galaxy
• The intragroup medium in loose groups of galaxies
• Near-infrared template spectra of normal galaxies: k-corrections, galaxy models and stellar populations
• X-Rays from NGC 3256: High-Energy Emission in Starburst Galaxies and Their Contribution to the Cosmic X-Ray Background
• Lx-SFR relation in star forming galaxies
• The X-Ray Derived Cosmological Star Formation History and the Galaxy X-Ray Luminosity Functions in the Chandra Deep Fields North and South
• ROSAT and ASCA Observations of X-ray Luminous starburst Galaxies : NGC3310 and NGC3690
• The Chandra Deep Field-North Survey. XV. Optically Bright, X-ray Faint Sources
• The Seyfert-Starburst Connection in X-rays. II. Results and Implications
• First Look XMM-Newton EPIC Observations of the Prototypical Starburst Galaxy M82
• The XMM-Newton/2dF survey I: X-ray properties of normal galaxies
• The XMM-Newton/2dF survey - II. The nature of X-ray faint optically bright X-ray sources
• The XMM-Newton Needles in the Haystack Survey: the local X-ray luminosity function of 'normal' galaxies
• The Needles in the Haystack survey: searching for X-ray selected normal galaxies

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• On the Lx-L6micron ratio as a diagnostic for Compton-thick AGN
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• A Hard X-ray Study of the Normal Star-Forming Galaxy M83 with NuSTAR
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• X-ray observations of sub-mm LABOCA galaxies in the eCDFS
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