Optical brightening of the neutron star transient MAXI J0556-332
ATel #13631; Albert K. H. Kong (National Tsing Hua Univ., Taiwan)
on 13 Apr 2020; 14:08 UT
Credential Certification: Albert Kong (akong@phys.nthu.edu.tw)
Subjects: Optical, Neutron Star, Transient
Referred to by ATel #: 14195
Following the report of the 4th outburst of the neutron star transient MAXI J0556-332 by MAXI on 2020 April 11 (ATel #13628), we observed the optical counterpart with the iTelescope.Net T17 0.43m telescope in Siding Spring, Australia on 2020 April 13 08:54 UT. With an exposure time of 180s and a R-band filter, we detected MAXI J0556-332 with an R magnitude of 18.5+/-0.3 by calibrating with the USNO-B1.0 catalogue. The counterpart was detected in the Digitized Sky Survey with a quiescent R magnitude of ~19.8. Therefore, we suggest that MAXI J0556-332 has brightened in optical as well. Based on previous optical observations during outbursts, the source can be as bright as R ~ 17 (ATel #3116). Hence, MAXI J0556-332 is likely on the rise of an ongoing outburst. More multi-wavelength observations are encouraged to follow up this new outburst.
