We present simultaneous optical and near-infrared spectra obtained during the 2021 outburst of the black hole transient 4U 1543-47. The X-ray hardness-intensity...

Following the recent report of a possible radio counterpart to the X-ray transient IGR J17098-3628 (ATEL #490), we re-investigated our Magellan I-band exposures...

We report the likely optical ID of the bright transient recently discovered in M31, CXOM31 J004253.1+411422 (Henze et al, ATEL #2356). With a peak X-ray...

Further to ATel #2455 (see also ATels #2380, #2384) detailing recent INTEGRAL observations of the 2010 outburst of the black hole candidate transient source GX...

Time resolved (40-sec resolution, ~6-hours per night), R-band photometry of the outbursting black hole candidate XTE J1118+480 (ATEL #383) was obtained with the...

We report the discovery of a new outburst of the black hole X-ray transient XTE J1118+480 (IAUC #7418, ATEL#64, #67). Observations carried out with the 0.8m...

GX 339-4 is currently brightening at X-ray, UV, optical and radio frequencies (ATel #1945, #1954, #1960). Our monitoring campaign with the Faulkes Telescope...

In ATel #1599; Krimm et al. report a gradual brightening and softening of SWIFT J1753.5-0127's X-ray emission, using the SWIFT satellite on June 30, 2008. We...

Observations of the black hole binary XTE J1859+226 revealed an unexpected optical re-brightening. Images were taken with the Nordic Optical Telescope (NOT)...