On the nature of the hard X-ray source IGR J2018+4043
Abstract
We found a very likely counterpart to the recently discovered hard X-ray source IGR J2018+4043 in the multi-wavelength observations of the source field. The source, originally discovered in the 20-40 keV band, is now confidently detected also in the 40-80 keV band, with a flux of (1.4 +/- 0.4) x 10(-11) erg cm(-2) s(-1). A 5 ks Swift observation of the IGR J2018+4043 field revealed a hard point-like source with the observed 0.5-10 keV flux of 3.4(+0.7)(-0.8) x 10(-12) erg cm(-2) s(-1) (90% confidence level) at alpha = 20h18m38.55s, delta = +40d41m00.4s (with a 4.2" uncertainty). The combined Swift-INTEGRAL spectrum can be described by an absorbed power-law model with photon index gamma = 1.3 +/- 0.2 and N_H = 6.1(+3.2)(-2.2) x 10(22) cm(-2). In archival optical and infrared data we found a slightly extended and highly absorbed object at the Swift source position. There is also an extended VLA 1.4 GHz source peaked at a beam-width distance from the optical and X-ray positions. The observed morphology and multiwavelength spectra of IGR J2018+4043 are consistent with those expected for an obscured accreting object, i.e. an AGN or a Galactic X-ray binary. The identification suggests possible connection of IGR J2018+4043 to the bright gamma-ray source GEV J2020+4023 (3EG J2020+4017) detected by COS B and CGRO EGRET in the gamma-Cygni SNR field.
Cite
@article{arxiv.astro-ph/0609676,
title = {On the nature of the hard X-ray source IGR J2018+4043},
author = {A. M. Bykov and A. M. Krassilchtchikov and Yu. A. Uvarov and J. A. Kennea and G. G. Pavlov and G. M. Dubner and E. B. Giacani and H. Bloemen and W. Hermsen and J. Kaastra and F. Lebrun and M. Renaud and R. Terrier and M. DeBecker and G. Rauw and J. -P. Swings},
journal= {arXiv preprint arXiv:astro-ph/0609676},
year = {2011}
}
Comments
5 pages, 3 figures, uses emulateapj style