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- Title
Accurate classification of 75 counterparts of objects detected in the 54-month Palermo Swift/BAT hard X-ray catalogue.
- Authors
Parisi, P.; Masetti, N.; Rojas, A. F.; Jiménez-Bailón, E.; Chavushyan, V.; Palazzi, E.; Bassani, L.; Bazzano, A.; Bird, A. J.; Galaz, G.; Minniti, D.; Morelli, L.; Ubertini, P.
- Abstract
Through an optical campaign performed at four telescopes located in the northern and southern hemispheres, we have obtained optical spectroscopy for 75 counterparts of unclassified or poorly studied hard X-ray emitting objects detected with Swift/BAT and listed in the 54-month Palermo BAT catalogue. All these objects also have observations taken with the Swift/XRT, ROSAT, or Chandra satellites, which allowed us to reduce the high-energy error box and pinpoint the most likely optical counterpart(s). We found that 69 sources in our sample are active galactic nuclei (AGNs) of which, 35 are classified as type 1 (with broad and narrow emission lines), 33 are classified as type 2 (with only narrow emission lines), and one is a high-redshift quasi-stellar object; the remaining 6 objects are galactic cataclysmic variables. Of the type 1 AGNs, 32 are objects of intermediate Seyfert type (1.2-1.9) and one is narrow-line Seyfert 1 galaxy; for 29 of the 35 type 1 AGNs, we have been able to estimate the central black hole mass and the Eddington ratio. Of the type 2 AGNs, two display optical features typical of the low-ionization nuclear emission-line region class, three are classified as transition objects, one is a starburst galaxy, and two are X-ray bright, optically normal galaxies. All galaxies classified in this work are relatively nearby objects (0.006-0.213) except for one at redshift 1.137.
- Subjects
REDSHIFT; OPTICAL spectroscopy; ACTIVE galactic nuclei; SEYFERT galaxies; GALAXIES
- Publication
Astronomy & Astrophysics / Astronomie et Astrophysique, 2014, Vol 561, p1
- ISSN
0004-6361
- Publication type
Article
- DOI
10.1051/0004-6361/201322409