An X-ray Transient and Optical Counterpart in the M31 Bulge

Benjamin F. Williams; Michael R. Garcia; Jeffrey E. McClintock; Albert K. H. Kong; Frank A. Primini; Stephen S. Murray

doi:10.1086/430876

paper

An X-ray Transient and Optical Counterpart in the M31 Bulge

arXiv:astro-ph/0504255 · doi:10.1086/430876

Abstract

We have obtained snapshot images of a transient X-ray source in M31 from Chandra ACIS-I and the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The Chandra position of the X-ray nova was R.A.=00:42:56.038 +/-0.08'', Dec.=+41:12:18.50 +/-0.07''. The transient was active for at least 6 months. Previous observations set an upper limit before the X-ray outburst, demonstrating variability by a factor of >100 and confirming the transient nature of the source. For the first 6 months after the initial detection, the X-ray luminosity was ~6 X 10 $^{37}$ erg/s; it then decayed to <5 X 10 $^{36}$ erg/s over the following 2 months. An HST observation 29 days after the initial X-ray detection revealed a source at R.A.=00:42:56.042, Dec.=+41:12:18.45 that was B=24.52 +/- 0.07. This optical source faded to B=24.95 +/- 0.08 $in 9 m o n t h s . T h eH S T i d e n t i f i c a t i o n o f an o pt i c a l so u r ce a tt h es am e p os i t i o na s t h e X - r a y so u r ce, f a d in g in co n cer tw i t h t h e X - r a y so u r ce, in d i c a t es t ha tt hi so pt i c a l so u r ce i s t h eco u n t er p a r t o f t h e X - r a y t r an s i e n t . T h e l a c k o f hi g h - ma sss t a r s in t h er e g i o n s ug g es t s t hi sso u r ce i s a l o w - ma ss X - r a y bina r y, an d t h e X - r a y an d o pt i c a l l u min os i t i es p r o v i d e a r o ug h or bi t a l p er i o d es t ima t eo f 8$ ^{+12}_{-5}$ days for the system.

arXiv comment16 pages, 4 tables, 2 figures, accepted for publication in ApJ

An X-ray Transient and Optical Counterpart in the M31 Bulge

Abstract

References in corpus (14)

Cited by in corpus (7)