Astrophys. J., 899, L20-L20 (2020/August-2)
Discovery of the black hole X-ray binary transient MAXI J1348-630.
TOMINAGA M., NAKAHIRA S., SHIDATSU M., OEDA M., EBISAWA K., SUGAWARA Y., NEGORO H., KAWAI N., SUGIZAKI M., UEDA Y. and MIHARA T.
Abstract (from CDS):
We report the first half-year monitoring of the new Galactic black hole candidate MAXI J1348-630, discovered on 2019 January 26 with the Gas Slit Camera on board the Monitor of All-sky X-ray Image (MAXI). During the monitoring period, the source exhibited two outburst peaks, where the first peak flux (at T = 14 days from the discovery of T = 0) was ∼4 Crab (2-20 keV) and the second one (at T = 132 days) was ∼0.4 Crab (2-20 keV). The source exhibited distinct spectral transitions between the high/soft and low/hard states and an apparent "q"-shape curve on the hardness-intensity diagram, both of which are well-known characteristics of black hole binaries (BHBs). Compared to other bright black hole transients, MAXI J1348-630 is characterized by its low disk temperature (∼0.75 keV at the maximum) and high peak flux in the high/soft state. The low peak temperature leads to a large innermost radius that is identified as the innermost stable circular orbit, determined by the black hole mass and spin. Assuming the empirical relation between the soft-to-hard transition luminosity (Ltrans) and the Eddington luminosity (LEdd), Ltrans/LEdd ≃ 0.02, and a face-on disk around a non-spinning black hole, the source distance and the black hole mass are estimated to be D ≃ 4 kpc and ∼7(D/4kpc)M☉, respectively. The black hole is more massive if the disk is inclined and the black hole is spinning. These results suggest that MAXI J1348-630 may host a relatively massive black hole among the known BHBs in our Galaxy.
© 2020. The American Astronomical Society. All rights reserved.
Black holes - Compact objects - High energy astrophysics - X-ray novae - Stellar accretion disks
View the references in ADS
To bookmark this query, right click on this link: simbad:2020ApJ...899L..20T and select 'bookmark this link' or equivalent in the popup menu