Normal galaxies in the XMM-Newton fields X-rays as a star formation indicator

作者：Rovilos E^*; Georgantopoulos I; Tzanavaris P; Pracy M; Whiting M; Woods D; Goudis C

来源：Astronomy & Astrophysics, 2009, 502(1): 85-U113.

DOI：10.1051/0004-6361/200912053

• galaxies: starburst
• X-rays: galaxies

Context. We use the first XMM serendipitous source catalogue (1XMM) to compile a sample of normal X-ray galaxies. Aims. We seek to expand the database of X-ray selected normal galaxies at intermediate redshifts and examine the relation between X-ray emission and star formation for late-type systems.
Methods. The candidates are selected based on their X-ray (soft spectra), X-ray to optical (log(f(x)/f(o)) < -2) and optical (extended sources) properties. 44 candidates are found and 35 are spectroscopically observed with the Australian National University's 2.3 m telescope to examine their nature.
Results. Of the 35 sources observed, 2 are AGN, 11 emission line galaxies, 12 absorption line galaxies, 6 have featureless spectra while 4 are associated with Galactic stars. We combine our emission line sample with earlier works forming the most comprehensive X-ray selected galaxy sample for the study of the X-ray luminosity to the H alpha luminosity - a well-calibrated star-formation indicator - relation.
Conclusions. We find that the X-ray luminosity strongly correlates with the H alpha luminosity, suggesting that the X-rays efficiently trace the star-formation.

• 出版日期2009-7