AX J1910.7+0917 and three newly discovered INTEGRAL sources

¹ ISDC, INTEGRAL Science Data Centre, Université de Genève, Chemin d’Ecogia 16, 1290 Versoix, Switzerland
e-mail: lucia.pavan@unige.ch
² Observatoire de Genève, Université de Genève, Chemin des Maillettes 51, 1290 Sauverny, Switzerland
³ INAF – Osservatorio Astronomico di Roma, via Frascati 33, 00044 Rome, Italy

Received: 10 August 2010
Accepted: 27 November 2010

Abstract

Aims. We take advantage of the high sensitivity of the IBIS/ISGRI telescope and the improvements in the data analysis software to investigate the nature of the still poorly known X-ray source AX J1910.7+0917, and search for closeby previously undetected objects.

Methods. We analyze all publicly available INTEGRAL data of AX J1910.7+0917, together with a number of archival observations that were carried out in the direction of the source with Chandra, XMM-Newton, and ASCA. In the IBIS/ISGRI field-of-view around AX J1910.7+0917, we discovered three new sources: IGR J19173+0747, IGR J19294+1327 and IGR J19149+1036; the latter is positionally coincident with the Einstein source 2E 1912.5+1031. For the first two sources, we also report the results of follow-up observations carried out with Swift /XRT.

Results. AX J1910.7+0917 features a clear variability in the X-rays. Its spectrum can be well described with an absorbed (N_H ~ 6 × 10²² cm^-2) power-law (Γ ≃ 1.5) model plus an iron line at 6.4 keV. We also obtained a refined position and report on possible infrared counterparts.

Conclusions. The present data do not allow for a unique classification of the sources. Based on the property of its X-ray emission and the analysis of a likely infrared counterpart, we investigate different possibilities for the nature of AX J1910.7+0917.