Optical Outburst of Aql X-1
ATel #41; R. Jain, C. Bailyn (Yale), M. Garcia and K. Rines (CfA), A. Levine (MIT), J. Espinoza and D. Gonzalez (CTIO)
on 10 May 1999; 21:51 UT
Credential Certification: Jerome A. Orosz (orosz@astro.psu.edu)
Subjects: Optical, Neutron Star, Transient
R. Jain and C. Bailyn (Yale); M. Garcia and K. Rines(CfA); A. Levine
(MIT); J. Espinoza and D. Gonzalez (CTIO) report YALO consortium
observations using the Yale 1-m telescope at CTIO and observations with
the 48" telescope at the Whipple Observatory:
Aql X-1 = V1333 Aql appears to be beginning a new outburst. This x-ray
binary outbursts approximately once per year, and based on its recent
outbursts was due to erupt. We have monitored the optical counterpart of
the soft X-ray transient Aquila X-1 since early March in Johnson R using
the YALO 1-m telescope. Compared to the average quiescent level, which
has a fluctuation of less than 0.1 magnitudes, the source had brightened
in R by approximately 0.2 magnitudes on MJD 51306.4 (May 08.3 UT). During
the night of May 10.2 -- 10.38 UT, we obtained 5 data points spanning nine
hours and found that the brightness increased from 0.4 to 0.55 magnitudes
brighter than the quiescent average. V-band data from the 48" telescope at
the Whipple Observatory show similar increases. We find that by MJD
51307.5 (May 09.5 UT) the source had brightened by approximately 0.4
magnitudes in V, compared to the average quiescent level. Subsequently we
obtained 3 YALO V images on May 10.2 -- 10.38 UT andfound an increase in
brightness of approximately 0.45 to 0.6 magnitudes, again compared to the
quiescent average. We will continue monitoring this source both in the
optical and in the X-ray using RXTE. Observations at all wavelengths are
encouraged.
