English

Optical Counterpart of The Ultraluminous X-ray Source NGC 1313 X-2

Astrophysics 2009-11-10 v1

Abstract

We present new optical and {\it Chandra} observations of the field containing the ultraluminous X-ray source NGC1313 X-2. On an ESO 3.6 m image, the {\it Chandra} error box embraces a R=21.6R=21.6 mag stellar-like object and excludes a previously proposed optical counterpart. The resulting X-ray/optical flux ratio of NGC 1313 X-2 is 500\sim 500. The value of fX/foptf_X/f_{opt}, the X-ray variability history and spectral distribution indicate a luminous X-ray binary in NGC 1313 as a likely explanation for NGC 1313 X-2. The inferred optical luminosity (L105LL\approx 10^5 L_\odot) is consistent with that of a 10M\approx 10 M_\odot companion.

Keywords

Cite

@article{arxiv.astro-ph/0309687,
  title  = {Optical Counterpart of The Ultraluminous X-ray Source NGC 1313 X-2},
  author = {L. Zampieri and P. Mucciarelli and R. Falomo and P. Kaaret and R. Di Stefano and R. Turolla and M. Chieregato and A. Treves},
  journal= {arXiv preprint arXiv:astro-ph/0309687},
  year   = {2009}
}

Comments

5 pages, 1 figure, to appear in Proc. of the BeppoSAX Symposium: "The Restless High-Energy Universe" (Amsterdam, May 5-8, 2003), E.P.J. van den Heuvel, J.J.M. in 't Zand, and R.A.M.J. Wijers (Eds), Nucl. Physics B. Suppl. Ser., Elsevier