PSR J1023+0038 is going into outburst
ATel #8995; M. Linares (IAC/ULL, NTNU), T. Shahbaz (IAC/ULL)
on 27 Apr 2016; 13:16 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Manuel Linares (linares@iac.es)
Subjects: X-ray, Binary, Neutron Star, Transient, Pulsar
Referred to by ATel #: 8997
The transitional "redback" millisecond pulsar PSR J1023+0038 was observed with Swift-XRT on 2016-04-07 and 2016-04-26. Both observations show the source at a flux of [1-2]E-9 erg/s/cm2 (0.5-10 keV, not corrected for absorption). This is more than two orders of magnitude brighter than the previous Swift-XRT observations of the source taken on 2016-02-18. The corresponding 0.5-10 keV luminosity on 2016 April 07 and 26 was 5.6e35 erg/s and 4.6e35 erg/s, respectively (d=1.37 kpc, Deller et al. 2012). The X-ray spectrum has softened with the increase in luminosity (photon index from 1.7+/-0.2 to 2-2.5).
This shows that PSR J1023+0038 is currently going into outburst. This the first time that this or any other nearby redback transitions into a full outburst state (Lx>1e34 erg/s), only observed to date in the globular cluster transitional millisecond pulsar M28-I (Papitto et al. 2013).
We encourage follow-up at all wavelengths.