The X-ray Quiescence of Swift J195509.6+261406 (GRB 070610): An Optical Bursting X-ray Binary?
Abstract
We report on an ~63 ks Chandra observation of the X-ray transient Swift J195509.6+261406 discovered as the afterglow of what was first believed to be a long-duration gamma-ray burst (GRB 070610). The outburst of this source was characterized by unique optical flares on timescales of second or less, morphologically similar to the short X-ray bursts usually observed from magnetars. Our Chandra observation was performed ~2 years after the discovery of the optical and X-ray flaring activity of this source, catching it in its quiescent state. We derive stringent upper limits on the quiescent emission of Swift J195509.6+261406, which argues against the possibility of this object being a typical magnetar. Our limits show that the most viable interpretation on the nature of this peculiar bursting source is a binary system hosting a black hole or a neutron star with a low-mass companion star (<0.12 M sun) and with an orbital period smaller than a few hours.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2011
- DOI:
- 10.1088/2041-8205/729/2/L21
- arXiv:
- arXiv:1101.3483
- Bibcode:
- 2011ApJ...729L..21R
- Keywords:
-
- stars: magnetic field;
- X-rays: individual: SWIFT J195509.6+261406;
- X-rays: stars;
- Astrophysics - Galaxy Astrophysics;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 5 pages, 3 figures, accepted for publication in ApJ Letters