Related papers: Two fast X-ray transients in archival Chandra data

A comparison of the XMM-Newton and Chandra Galactic Centre (GC) Surveys has revealed two faint X-ray transients with contrasting properties. The X-ray spectrum of XMM J174544-2913.0 shows a strong iron line with an equivalent width of ~2…

Recently, in a study the X-ray flaring activity of Sgr A* with Chandra and XMM-Newton public observations from 1999 to 2014 and 2014 Swift data, it has been argued that the "bright and very bright" flaring rate raised from 2014 Aug. 31.…

The massive black hole + Wolf-Rayet binary IC10 X-1 was observed in a series of 10 Chandra and 2 XMM-Newton observations spanning 2003-2012, showing consistent variability around 7 x10^37 erg/s, with a spectral hardening event in 2009. We…

Two X-ray sources were recently discovered by Irwin et al. in compact companions to elliptical galaxies to show ultra-luminous flares with fast rise (~ minute) and decay (~ hour), and with a peak luminosity ~10^{40-41} erg/s. Together with…

INTEGRAL monitoring of the Galactic Plane is revealing a growing number of recurrent X-ray transients, characterised by short outbursts with very fast rise times (~ tens of minutes) and typical durations of a few hours. A substantial…

We present X-ray imaging and spectroscopy of the redshift z=7.084 radio-quiet quasar ULAS J112001.48+064124.3 obtained with Chandra and XMM-Newton. The quasar is detected as a point source with both observatories. The Chandra observation…

In the last 15 years, 6 dedicated observation programs were carried out to monitor ~20 deg around the galactic center for transient activity above a few keV. Transient activity from low-mass X-ray binaries shows a strong preference for this…

The unprecedented spatial resolution of the Chandra observatory opens the possibility to detect with relatively high accuracy proper motions at X-ray wavelengths. We have conducted an astrometric study of three of the "Magnificent Seven",…

We have realised a simple prototype system to perform searches for short timescale optical transients, utilising the novel drift scan imaging technique described by Tingay (2020). We used two coordinated and aligned cameras, with an overlap…

We present two years of intense Swift monitoring of three SFXTs, IGR J16479-4514, XTE J1739-302, and IGR J17544-2619 (since October 2007). Out-of-outburst intensity-based X-ray (0.3-10keV) spectroscopy yields absorbed power laws with by…

We combine 9 ROSAT, 9 Chandra, and 2 XMM-Newton observations of the Cen~A galaxy to obtain the X-ray light curve of 1RXH J132519.8-430312 (=CXOU J132519.9$-$430317) spanning 1990 to 2003. The source reached a peak 0.1-2.4 keV flux…

We report new X-ray results from the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL), Swift, Chandra, and XMM-Newton observations of the hitherto poorly studied unidentified X-ray transient IGR J17419-2802. We studied in detail…

Tidal disruption events (TDEs), which occur when stars enter the tidal radii of supermassive black holes (SMBHs) and are subsequently torn apart by their tidal forces, represent intriguing phenomena that stimulate growing research interest…

The phenomenology of a subclass of High Mass X-ray Binaries hosting a blue supergiant companion, the so-called Supergiant Fast X-ray Transients (SFXTs), is reviewed. Their number is growing, mainly thanks to the discoveries performed by the…

We discuss the results of cross-correlating catalogs of bright X-ray binaries with the Yale Southern Proper Motion catalog (version 4.0). Several objects already known to have large proper motions from Hipparcos are recovered. Two…

We have identified a new transient luminous low-mass X-ray binary, NGC 6440 X-2, with Chandra/ACIS, RXTE/PCA, and Swift/XRT observations of the globular cluster NGC 6440. The discovery outburst (July 28-31, 2009) peaked at L_X~1.5*10^36…

Three different types of very intense, quasi-regular X-ray bursts have been observed from the Galactic superluminal X-ray transient source GRS 1915+105 with the Pointed Proportional Counters of the Indian X-ray Astronomy Experiment onboard…

In this Paper we report on our analysis of three Chandra observations of the accretion-powered millisecond X-ray pulsar IGR J00291+5934 obtained during the late stages of the 2004 outburst. We also report the serendipitous detection of the…

In the last 10 years multi-wavelength fast variability studies of low mass X-ray binaries have shown a dramatic development. A key discovery was the detection of O-IR sub-second fluctuations in two black-hole transients, lagging the X-rays…

The accretion mechanism producing the short flares observed from the Supergiant Fast X-ray Transients (SFXT) is still highly debated and forms a major part in our attempts to place these X-ray binaries in the wider context of the High Mass…