Optical identification of IGR J19140+0951

¹ SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands e-mail: jeanz@sron.nl
² Astronomical Institute, Utrecht University, PO Box 80000, 3508 TA Utrecht, The Netherlands
³ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02198, Massachusetts, USA
⁴ Dept. of Astrophysics, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands
⁵ European Southern Observatory, Alonso de Cordova 3107, Santiago, Chile

Received: 12 May 2005
Accepted: 2 November 2005

Abstract

IGR J19140+0951 was discovered by INTEGRAL in 2003 in the 4–100 keV band. Observations with INTEGRAL and RXTE provide a tentative identification as a high-mass X-ray binary (HMXB) with a neutron star as accretor. However, an optical counterpart was thus far not established, nor was the presence of a pulsar which is commonly observed in HMXBs. We observed IGR J19140+0951 with Chandra and find the source to be active at a similar flux as previous measurements. The lightcurve shows a marginally significant oscillation at 6.5 ks which requires confirmation. We determine a sub-arcsecond position from the Chandra data and identify the heavily reddened optical counterpart 2MASS 19140422+0952577 in the 2MASS catalog. Optical follow-up observations with the William Herschel Telescope at La Palma exhibit a continuum spectrum coming out of extinction above 7000 Å without strong absorption or emission features. and K_s band photometry point to an optical counterpart with an extinction of . The extinction is consistent with the interstellar value. None of the data reject the suspicion that IGR J19140+0951 is an HMXB with additional circumstellar obscuration around the accretor.