AXJ1749+684: a narrow emission-line galaxy with a flat X-ray spectrum

Abstract

We report the serendipitous detection of an X-ray source, AXJ1749+684, with the ASCA Gas Imaging Spectrometer. AXJ1749+684 is identified with a LINER/starburst-type spiral galaxy KUG 1750+683A at a redshift z = 0.05. It has a hard X-ray spectrum, consistent with that of the X-ray background (XRB) in the 1-10 keV band. Despite the optical classification, the X-ray luminosity cannot be explained by starburst activity. Combined with spatial variations in the optical emission line ratios, this suggests the presence of an obscured Seyfert nucleus embedded within a starforming galaxy. Similar behaviour could explain the ambiguous properties of the faint narrow-line X-ray galaxies (NLXGs) emerging from deep X-ray surveys.

MNRAS Letters in press, 6 pages, 7 figures in MNRAS LaTex style

Cited by in corpus (8)

• A 3 dimensional diagnostic diagram for Seyfert 2s: probing X-ray absorption and Compton thickness
• Optical Identification of the ASCA Medium Sensitivity Survey in the Northern Sky: Nature of Hard X-ray-selected Luminous Active Galactic Nuclei
• A candidate of a type-2 QSO at z=0.9: Large X-ray absorption with a strong broad-H-alpha emission line
• ASCA observations of deep ROSAT fields IV.IR and hard X-ray observations of an obscured high-redshift QSO
• Optical Identification of the Hardest X-ray Source in the ASCA Large Sky Survey
• The BeppoSAX spectrum of the composite galaxy Mrk609
• Starburst activity in a ROSAT Narrow Emission-Line Galaxy
• Faint galaxies and the X-ray background