Rebrightening of MAXI J1348-630

ATel #13188; Aisha Al Yazeedi, David M. Russell (NYU Abu Dhabi), Fraser Lewis (Faulkes Telescope Project & Astrophysics Research Institute, LJMU), Maria Cristina Baglio, D. M. Bramich, Payaswini Saikia (NYU Abu Dhabi)
on 13 Oct 2019; 04:42 UT
Credential Certification: David M. Russell (dave.russell5@gmail.com)

Tweet

The black hole candidate X-ray binary, MAXI J1348-630 was discovered by the MAXI X-ray telescope on 2019 Jan 26 (MJD 58509; ATel #12425). After the first outburst period, we reported an optical brightening of the source in 2019 May-June (ATel #12829) which was also seen at X-ray (ATel #12838) wavelengths. The brightening peaked around 2019 Jun 6 (MJD ~58640) at a magnitude of g' = 17.08 +- 0.02, i' = 15.46 +- 0.01.

The source then faded by 0.012 mag/day until around 2019 Jul 11 (MJD ~58675) after which it faded more rapidly, at 0.082 mag/day. During the faster decay some flaring is seen for a few days before 2019 Aug 30 (MJD 58725), when the source was very faint, with g' = 22.5 +- 0.34, i' = 19.54 +- 0.07. The source remained faint for at least a week, and on MJD 58731.7 it was at i' = 20.33 +- 0.36 mag. After this date, the source started to brighten. The above faintest magnitudes could represent the quiescent magnitudes of the source, although it only remained at these flux levels for a short period of time. Further observations will be required to confirm the quiescent magnitudes. The most recent magnitudes show a brightening, with g' = 19.98 +- 0.28, i' = 17.70 +- 0.072 on 2019 Sep 12 (MJD 58738.9).

We note that since 2019 Sep 18 (MJD 58744), the MAXI all-sky X-ray telescope has been detecting MAXI J1348-630 with >3 sigma significance on most days (daily average count rates). From now, the source is not visible from the ground until late December. Multi-wavelength observations are encouraged at this time to study the re-brightening.

The LCO observations are part of an on-going monitoring campaign of ~ 40 low-mass X-ray binaries (Lewis et al. 2008) with LCO and the Faulkes Telescopes. This work makes use of observations from the Las Cumbres Observatory (LCO). We acknowledge the support of the NYU Abu Dhabi Research Enhancement Fund under grant RE124.

Optical LCO light curves of MAXI J1348-630