All-sky monitor observations of flares from Aquila X-1
Abstract
The All-Sky Monitor on Ariel 5 has observed the Aquila-Serpens region on a quasi-continuous basis since launch in 1974 October. During this time Aql X-1 exhibited major flares in 1975 June and 1976 June, with the measured X-ray intensities increasing more than an order of magnitude to approximately that measured from the Crab nebula, and remaining above the experiment threshold (approximately 0.1 x s crab) for almost two months in both instances. These outbursts resemble the X-ray light curves of transient sources such as A0620-00 and are interpreted in terms of episodic accretion in a dwarf nova-like binary. Combination of the epoch of phase minimum for the 1.3d period (1976) with the 1975 data yields a value of P = 1.28d + or - 0.02d with a corresponding modulation of approximately 3% (3-6 keV). Modulation at this period is not apparent in the 1976 data, with an upper limit of 2% during that time.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- October 1976
- Bibcode:
- 1976STIN...7633102K
- Keywords:
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- All Sky Photography;
- Flares;
- X Ray Astronomy;
- Ariel 5 Satellite;
- Binary Stars;
- Crab Nebula;
- Dwarf Stars;
- Novae;
- Astronomy