Related papers: Upper Limits on X-ray Emission from Two Rotating R…
We report on the results of a four-year long X-ray monitoring campaign of the central 1.2 square degrees of our Galaxy, performed with Chandra and XMM-Newton between 2005 and 2008. Our study focuses on the properties of transient X-ray…
We observed the periodic radio transient GLEAM-X J162759.5-523504.3 (GLEAM-X J1627) using the Chandra X-ray Observatory for about 30-ks on January 22-23, 2022, simultaneously with radio observations from MWA, MeerKAT and ATCA. Its radio…
RX J1856.5-3754 is the X-ray brightest among the nearby isolated neutron stars. Its X-ray spectrum is thermal, and is reproduced remarkably well by a black-body, but its interpretation has remained puzzling. One reason is that the source…
We have monitored the transient neutron star low-mass X-ray binary 1RXS J180408.9-342058 in quiescence after its ~4.5 month outburst in 2015. The source has been observed using Swift and XMM-Newton. Its X-ray spectra were dominated by a…
We report the discovery of a luminous ultra-soft X-ray excess in a radio-loud narrow-line Seyfert1 galaxy, RXJ1633+4718, from archival ROSAT observations. The thermal temperature of this emission, when fitted with a blackbody, is as low as…
XMM-Newton observations of the middle-aged radio-quiet $\gamma$-ray pulsar J0554+3107 allowed us, for the first time, firmly identify it in X-rays by detection of pulsations with the pulsar period. In the 0.2-2 keV band, the pulse profile…
We report on spectral and intensity variability analysis from a Chandra/ACIS-S observation of the transient, type-I X-ray bursting low-mass X-ray binary Cen X-4. The quiescent X-ray spectrum during this observation is statistically…
We describe Chandra, HST, and radio observations that reveal a radio-quiet but magnetospherically active neutron star in the error circle of the high-energy gamma-ray source 3EG J1835+5918, the brightest of the unidentified EGRET sources at…
We report on a 10 ksec observation of the double pulsar system J0737-3039 obtained with the Chandra X-ray Observatory's Advanced CCD Imaging Spectrometer. We detect the system as a point source with coordinates (J2000) RA = 07:37:51.23,…
I describe recent high-resolution X-ray spectroscopy of surface emission from nearby, thermally emitting neutron stars. I focus on RX J0720.4-3125, RX J1308.6+2127, and RX J1605.3+3249, all of which have similar temperature, but differ in…
We present results of the analysis of data collected in 57-ks XMM-Newton and 505-ks Chandra observations of the nearby ~= 120 pc isolated neutron star RX J1856.5-3754. We confirm most of the statements made by Burwitz et al. (2001) who…
We report on the quiescent spectrum measured with Chandra/ACIS-S of the transient, type-I X-ray bursting neutron star Aql X-1, immediately following an accretion outburst. The neutron star radius, assuming a pure hydrogen atmosphere and…
Using the Parkes radio telescope, we have searched for pulsed radio emission from the recently discovered X-ray pulsars AX J1811.5-1926 and PSR J0537-6910 in the supernova remnants G11.2-0.3 and N157B, respectively. We detected no…
XMM-Newton and Chandra observations of the transient 7.8 s pulsar XTE J1829-098 are used to characterize its pulse shape and spectrum, and to facilitate a search for an optical or infrared counterpart. In outburst, the absorbed, hard X-ray…
We discuss efforts to determine the mass, radius, and surface composition of the nearby compact object RX J185635-3754 from its multi-wavelength spectral energy distribution. We compute non-magnetized model atmospheres and emergent spectra…
We have completed part of a program to study the X-ray emission properties of old rotation-powered pulsars with XMM-Newton in order to probe and identify the origin of their X-radiation. The X-ray emission from these old pulsars is largely…
We present the results of an 80 ks Chandra ACIS-S observation of the double pulsar system J0737-3039. Furthermore, we report on spectral, spatial and timing analysis of the combined X-ray observations performed so far for this system.…
We observed the "micro-quasar" GRS 1758-258 four times with Chandra. Two HRC-I observations were made in 2000 September-October spanning an intermediate-to-hard spectral transition (identified with RXTE). Another HRC-I and an ACIS/HETGS…
RX J1301.9+2747 is a unique active galaxy with supersoft X-ray spectrum that lacks significant emission at energies above 2 keV. In addition, it is one of few galaxies displaying quasi-periodic X-ray eruptions that recur on a timescale of…
We present timing measurements, astrometry, and high-resolution spectra of a number of nearby, thermally emitting, isolated neutron stars. We use these to infer magnetic field strengths and distances, but also encounter a number of puzzles.…