MAXI/GSC Discovery of the Black Hole Candidate MAXI J1305-704

Abstract

We present the first results on the new black hole candidate, MAXI J1305-704, observed by MAXI/GSC. The new X-ray transient, named as MAXI J1305-704, was first detected by the MAXI-GSC all-sky survey on 2012 April 9 in the direction to the outer Galactic bulge at (l,b)=(304.2deg,-7.6deg). The Swift/XRT follow-up observation confirmed the uncatalogued point source and localized to the position at (13h06m56s.44,-70d27'4".91). The source continued the activity for about five months until 2012 August. The MAXI/GSC light curve in the 2--10 keV band and the variation of the hardness ratio of the 4-10 keV to the 2-4 keV flux revealed the hard-to-soft state transition on the the sixth day (April 15) in the brightening phase and the soft-to-hard transition on the ~60th day (June 15) in the decay phase. The luminosity at the initial hard-to-soft transition was significantly higher than that at the soft-to-hard transition in the decay phase. The X-ray spectra in the hard state are represented by a single power-law model with a photon index of ~2.0, while those in the soft state need such an additional soft component as represented by a multi-color disk blackbody emission with an inner disk temperature ~0.5--1.2 keV. All the obtained features support the source identification of a Galactic black-hole binary located in the Galactic bulge.

arXiv comment6 pages, 5 figures, 1 table, accepted for publication in PASJ

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Cited by in corpus (11)

• BlackCAT: A catalogue of stellar-mass black holes in X-ray transients
• WATCHDOG: A Comprehensive All-Sky Database of Galactic Black Hole X-ray Binaries
• Accretion disk and ionized absorber of the 9.7-hour dipping black hole binary MAXI J1305-704
• Dynamical confirmation of a stellar-mass black hole in the transient X-ray dipping binary MAXI J1305-704
• Broad-band spectral study of X-ray transient MAXI J1820+070 using Swift/XRT and NuSTAR
• A Black Hole Kicked At Birth: MAXI J1305-704
• A Comprehensive X-ray Report on AT2019wey
• A new X-ray nova MAXI J1910-057 (= Swift J1910.2-0546) and mass-accretion inflow
• Re-awakening of GRS 1716--249 after 23 years, observed by {\it Swift}/XRT and {\it NuSTAR}
• Using X-ray continuum-fitting to estimate the spin of MAXI J1305-704
• X-ray view of emission lines in optical spectra: Spectral analysis of the two low-mass X-ray binary systems Swift J1357.2-0933 and MAXI J1305-704