[ Previous | Next ]
ATEL # 1949; J.-C. Leyder (IAG, Liège), R. Walter (ISDC, Geneva), P. Lubinski (CAMK, Warsaw & ISDC, Geneva)
on 4 Mar 2009; 20:51 UT
Distributed as an Instant Email Notice (Request for Observations)
Password Certification: Roland Walter (Roland.Walter@obs.unige.ch)
Subjects: X-ray, Gamma Ray, Request for Observations, Binaries, Transients
The Be X-ray transient 1A 1118-615 has been observed in outburst by Swift starting on January 4, 2009 (see ATel #1896). According to RXTE observations, this outburst lasted for about 20 days, before returning to its previous level (see the ASM lightcurve).
This source belongs to the same field as Eta Carinae, which is currently being observed by INTEGRAL. 1A 1118-615 has been detected flaring again by both the JEM-X and ISGRI instruments during recent observations of INTEGRAL (between 2009-02-03 07:25:37 UT and 2009-02-04 04:00:06 UT, 2009-02-26 20:57:07 UT and 2009-02-28 02:45:24 UT, 2009-03-01 21:56:16 UT and 2009-03-03 02:40:14 UT, for a total of 270 ks). The source is variable with a flux of the order of 1E-9 erg/s/cm^2 (in the 3-100 keV range) and detected up to above 100 keV. The ISGRI position is RA = 11h 21m 00.10s, Dec = -61deg 54' 29.8'' (J2000, +/-0.6 arcmin @90% error).
This field will be extensively observed by INTEGRAL over the coming days (in particular between 2009-03-05 03:14:56 UT and 2009-03-06 02:55:46 UT, 2009-03-07 17:30:24 UT and 2009-03-09 02:23:43 UT, 2009-03-13 19:04:17 UT and 2009-03-15 01:08:08 UT). Spectroscopic monitoring in the optical is encouraged, as the Halpha equivalent width is known to be related to the X-ray activity (Coe et al. 1994, A&A 289, 784).