Back to Volume
Paper: AGN Search From Multicolor CCD Photometric Observations of Faint ROSAT X-ray Sources in a One Square Degree Field
Volume: 284, AGN Surveys, IAU Colloquium 184
Page: 261
Authors: Xue, Suijian; Zhou, Xu; Zhang, H.
Abstract: We present the optical identifications of 75 X-ray sources in a 1 sq. deg. overlapping region, T329 of BATC sky survey with a medium deep ROSAT survey (Molthagen et al. 1997), based on multi-color CCD imaging observations made for the T329 utilizing BAO 60/90 cm Schmidt telescope with 15 intermediate-band filters covering the wavelength range 3360-9745 AA. These X-ray sources are relatively faint (CR << 0.2 s-1) and thus mostly are not included in the RBS catalogue and also remained as unidentified sources in a previous identification program carried out by the Hamburg Quasar Survey. Within their position-error circles, All of the X-ray sources were observed to have one or more spatially associated optical counterparts down to the magnitude mv=21.5. The majority of these optical objects could be classified according to their SED information constructed from the 15 color photometric catalogue of T329. This finally leads to 43 (~57%) of 75 X-ray sources are identified with AGNs, 19 (~25%) and 8 (~11%) are identified with various types of galaxies and late stars respectively. About one third sources in the AGN list (including 4 known AGNs) have follow up spectroscopic observations, confirming their QSO/Seyfert or NELG nature. Further more spectroscopic observations are partially ongoing with the Multiple Object Fiber Spectrograph (MOFS) of SAO 6m telescope, which will help to form a complete, X-ray flux limited AGN sample in a 1 square degree field.
Back to Volume