The Second Optical Outburst of XTE J1118+480
ATel #412; Y. Chou (National Central University), A. Chen (National Cheng Kung University), P. S. Chiang (National Cheng Kung University), C. P. Hu (National Central University), R. H. Hu(National Central University)
on 18 Feb 2005; 06:40 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Yi Chou (yichou@astro.ncu.edu.tw)
Subjects: Optical, Binary, Black Hole, Transient
Referred to by ATel #: 420, 424
We report the results from our continuous monitoring of the outbursting black hole X-ray transient XTE J1118+480 (KV UMa, ATEL #383, #384, #385, #386, #387, #389, #393, #399, #402, #404) made by Lulin One-meter Telescope (LOT), Taiwan. After about a month declining to V=17.4, its optical flux was found rising again on Feb 13 and has been increasing since. Our latest data show that the source is ~1 mag brighter than the lowest state on Feb 12. The mean V band magnitudes from Feb. 6 to 16 measured by LOT were: Feb 6.745, 15.01; 7.694, 15.20; 8.733, 15.42; 11.809, 16.48; 12.851, 17.43; 13.831, 16.92, 14.820, 16.57; 15.787, 16.57; 16.782, 16.67. Our discovery implies that the source is on its second outburst state, which is probably similar to its last outburst in 2000. Observations in all wavebands are strongly suggested.
