New AGN classifications in the Swift/BAT All-Sky Hard X-ray Survey

TL;DR

This study refines the classification of 8 newly identified AGN from the Swift/BAT survey using optical spectroscopy and archival X-ray data, revealing their true nature and redshifts.

Contribution

It provides new, precise optical classifications for 8 AGN, improving upon previous tentative identifications based solely on X-ray data.

Findings

7 Seyfert 2 galaxies identified

1 Seyfert 1 galaxy identified

Redshifts range from 0.009 to 0.068

Abstract

Through an optical campaign performed at the San Pedro Martir (Mexico) Telescope and using the 6dF archive (http://www.aao.gov.au/local/www/6df, Jones et al. 2004), we determine or give a better classification for 8 newly discovered Active Galactic Nuclei (AGN) in the Swift/BAT 22-months All-sky Hard X-ray Survey (Baumgartner et al. 2008, Tueller et al. 2010). All these objects have observations taken with Swift/XRT or Chandra or XMM archival data which allowed us to pinpoint their optical counterpart thanks to the precise (better than a few arcsec) soft X-ray positions afforded by these observatories. This information enabled us to obtain optical spectra of all these counterparts, since only three spectra are available on-line, but not flux calibrated, allowing us to reveal their real nature (Baumgartner et al. 2008 give only a tentative classification based upon their X-ray properties). Here we present the spectra, along with the corresponding finding charts obtained from the DSS-II red survey, of these 8 sources. We found that our sample is composed of 7 Seyfert 2 and one Seyfert 1, with redshift between 0.009 and 0.068.