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Date and Time of the Query: 2019-05-22 T11:44:25 PDT
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For refcode 2005MNRAS.360..782G:
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Copyright by Royal Astronomical Society. 2005MNRAS.360..782G The XMM-Newton Needles in the Haystack Survey: the local X-ray luminosity function of 'normal' galaxies Georgantopoulos, I.; Georgakakis, A.; Koulouridis, E. Abstract. In this paper we estimate the local (z < 0.22) X-ray luminosity function of 'normal' galaxies derived from the XMM-Newton Needles in the Haystack Survey. This is an on-going project that aims to identify X-ray-selected normal galaxies (i.e. non-AGN dominated) in the local Universe. We are using a total of 70 XMM-Newton fields covering an area of 11 deg^2^ which overlap with the Sloan Digital Sky Survey Data Release 2. Normal galaxies are selected on the basis of their resolved optical light profile, their low X-ray-to-optical flux ratio [log(f_x_/f_o_) < - 2] and soft X-ray colours. We find a total of 28 candidate normal galaxies to the 0.5-8keV band flux limit of ~2 x 10^-15^erg cm^-2^s^-1^. Optical spectra are available for most sources in our sample (82 per cent). These provide additional evidence that our sources are bona fide normal galaxies with X-ray emission coming from diffuse hot gas emission and/or X-ray binaries rather than a supermassive black hole. 16 of our galaxies have narrow emission lines or a late-type spectral energy distribution (SED) while the remaining 12 present only absorption lines or an early-type SED. Combining our XMM-Newton sample with 18 local (z < 0.22) galaxies from the Chandra Deep Field North and South surveys, we construct the local X-ray luminosity function of normal galaxies. This can be represented with a Schechter form with a break at L_*_~ 3^+1.4^_-1.0_ x 10^41^ergs^-1^ and a slope of {alpha}~ 1.78 +/- 0.12. Using this luminosity function and assuming pure luminosity evolution of the form ~(1 +z)^3.3^ we estimate a contribution to the X-ray background from normal galaxies of ~10-20 per cent (0.5-8keV). Finally, we derive, for the first time, the luminosity functions for early- and late-type systems separately.
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