Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-12-15
Mon.Not.Roy.Astron.Soc.375:1463-1470,2007
Astronomy and Astrophysics
Astrophysics
9 pages, 8 figures, accepted for publication in MNRAS
Scientific paper
10.1111/j.1365-2966.2006.11409.x
Phase-resolved high resolution optical spectroscopy has revealed narrow N III and He II emission lines from the soft X-ray transient Aquila X-1 during its 2004 outburst that move as a function of the orbit consistent with the phasing of the donor star. Under the assumption that these lines come from the irradiated side of the donor star, we can constrain its K_2 velocity to >247+/-8 km/s, and derive a mass function of f(M_1)>1.23+/-0.12M_sun. Estimates for the rotational broadening based on the emission components suggest a possible massive neutron star of >1.6M_sun (at 95% confidence). However, an updated ephemeris and additional high resolution spectroscopy of Aql X-1 during a future outburst are warranted in order to confirm that the narrow lines indeed originate on the donor star surface, and reliably characterise the system parameters of this important X-ray binary. Spectra taken during the end of the outburst show that the morphology of the emission lines changed dramatically. No donor star signature was present anymore, while the presence of narrow low-velocity emission lines became clear, making Aql X-1 a member of the slowly growing class of low-velocity emission line sources.
Barnes A. D.
Casares Jorge
Charles Phil A.
Cornelisse Remon
Hynes Robert I.
No associations
LandOfFree
A detection of the donor star of Aquila X-1 during its 2004 outburst? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A detection of the donor star of Aquila X-1 during its 2004 outburst?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A detection of the donor star of Aquila X-1 during its 2004 outburst? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-132213