The RXTE All-Sky monitor shows new detections of the black hole binary, XTE J1118+480, reported to be in optical outburst (ATEL #383). The source is first seen...
Fast X-ray/IR observations of the black hole transient Swift J1753.5–0127: From an IR lead to a very long jet lag
We report two epochs of simultaneous near-infrared (IR) and X-ray observations of the low-mass X-ray binary black hole candidate Swift J1753.5–0127 with a...
First gravitational-wave burst GW150914: MASTER optical follow-up observations
The Advanced LIGO observatory recently reported the first direct detection of the gravitational waves (GWs) predicted by Einstein & Sitzungsber. We report on...
Follow-up Survey for the Binary Black Hole Merger GW200224_222234 Using Subaru/HSC and GTC/OSIRIS
The LIGO/Virgo detected a gravitational wave (GW) event, named GW200224_222234 (also known as S200224ca) and classified as a binary-black hole coalescence, on...
Furiously fast and red: sub-second optical flaring in V404 Cyg during the 2015 outburst peak
We present observations of rapid (sub-second) optical flux variability in V404 Cyg during its 2015 June outburst. Simultaneous three-band observations with the...
Galactic Black Hole Transient H1743-322 in transition to the hard state
Galactic black hole transient H1743-322 has been in outburst since UT 2009 May 26, (ATELs #2058, #2062). The RXTE PCA count rate has been dropping since 2009...
Gamma-ray observations of MAXI J1820+070 during the 2018 outburst
MAXI J1820+070 is a low-mass X-ray binary with a black hole (BH) as a compact object. This binary underwent an exceptionally bright X-ray outburst from 2018...
The black hole X-ray binary (BHXB) GX 339-4 continues to fade in the optical, and has now reached its faintest optical flux since (at least) the start of its...
Hard-state Accretion Disk Winds from Black Holes: The Revealing Case of MAXI J1820+070
We report on a detailed optical spectroscopic follow-up of the black hole (BH) transient MAXI J1820+070 (ASASSN-18ey). The observations cover the main part of...