We present hard X-ray observations of the nearby radio galaxy M87 and the core of the Virgo cluster using the Rossi X-ray Timing Explorer. These are the first hard X-ray observations of M87 not affected by contamination from the nearby Seyfert 2 galaxy NGC 4388. Thermal emission from Virgo’s intracluster medium is clearly detected and has a spectrum indicative of kT ≈ 2.5 keV plasma with approx...

We present hard X-ray observations of the nearby radio galaxy M87 and the core of the Virgo cluster using the Rossi X-ray Timing Explorer. These are the first hard X-ray observations of M87 not affected by contamination from the nearby Seyfert 2 galaxy NGC 4388. Thermal emission from Virgo’s intracluster medium is clearly detected and has a spectrum that is well described by a kT ≈ 2.7 keV ther...

We examine the possibility that Ultraluminous X-ray sources (ULXs) represent the extreme end of the black hole X-ray binary (XRB) population. Based on their X-ray properties, we suggest that ULXs are persistently in a high/hard spectral state and we propose a new disk–jet model that can accomodate both a high accretion rate and a hard X-ray spectrum. Our model predicts that the modified disk em...

We present hard X-ray observations of the nearby radio galaxy M87 and the core of the Virgo cluster using the Rossi X-ray Timing Explorer. These are the first hard X-ray observations of M87 not affected by contamination from the nearby Seyfert 2 galaxy NGC 4388. Thermal emission from Virgo’s intracluster medium is clearly detected and has a spectrum that is well described by a kT 2:5 keV therma...

During a systematic search for periodic signals in a sample of ROSAT PSPC light curves, we discovered ∼ 8.9 s X–ray pulsations in 2E0050.1–7247, a variable X–ray source in the Small Magellanic Cloud. The source was detected several times between 1979 and 1993 at luminosity levels ranging from ∼ 5 × 10 erg s up to 1.4 × 10 erg s with both the Einstein IPC and ROSAT PSPC. The X–ray energy spectru...

We revisit the flare on 1992 January 13, which is now universally termed the “Masuda flare”. Our work is motivated by the remarkable improvement of Yohkoh hard X-ray imaging, which was only achieved after the intensive investigations on this famous event. With the calibrated Hard X-ray Telescope (HXT) data, we find that the hard X-ray coronal source is indeed a loop-top source, located slightly...