相关论文: High resolution X-ray spectroscopy of V4641 Sgr du…
We report the results of a simultaneous X-ray and optical spectroscopy campaign on the Galactic black hole X-ray binary V4641 Sgr, carried out with XRISM and the Seimei telescope during a low-luminosity phase towards the end of its 2024…
We present an optical spectroscopic study of the black hole X-ray transient V4641 Sgr (=SAX J1819.3-2525) covering the 1999, 2002 and 2004 outbursts. The spectra were taken over 22 different epochs during the low luminosity phases that…
The X-ray spectrum of the Galactic X-ray binary V4641 Sgr in outburst has been found to exhibit a remarkably broad emission feature above 4 keV, with inferred equivalent widths up to 2 keV. Such a feature was first detected during the X-ray…
V4641 Sgr is a low-mass black hole X-ray binary system with somewhat puzzling spectral characteristics during its soft state. Recent high-resolution spectroscopic studies of V4641 Sgr have revealed strong ionized emission line features in…
We present the first Chandra results of the giant molecular cloud Sagittarius B2 (Sgr B2), located about 100 pc away from the Galactic center. Diffuse X-rays are clearly separated from one-and-a-half dozen resolved point sources. The X-ray…
We present an analysis of three archival Chandra observations of the black hole V4641 Sgr, performed during a decline into quiescence. The last two observations in the sequence can be modeled with a simple power-law. The first spectrum,…
We analyze observations of the low mass X-ray binary 2S0921-63 obtained with the gratings and CCDs on Chandra and XMM. This object is a high inclination system showing evidence for an accretion disk corona (ADC). Such a corona has the…
X-ray transients provide unique opportunity to probe accretion regimes of at a vastly different accretion rates. We analyze a collection of the RXTE observations (Galactic Center scans, ASM monitoring and a pointed observation) of enigmatic…
On two occasions, we obtained nearly simultaneous ~ 4 kilosecond snapshot observations of the Galactic black hole and microquasar XTE J1550-564 with Chandra and RXTE near the peak of its May, 2000 outburst. The low-energy sensitivity of…
We present results from observations of persistent black hole candidates with the High Energy Transmission Gratings aboard the Chandra X-ray Observatory. The sources include LMC X-1, LMC X-3, GRS 1758-258, and Cyg X-1. Along with the…
This paper reports on the early Chandra view of the Galactic center (GC) activities. The massive black hole Sgr A* is extremely faint, while more bright diffuse X-ray emission is prevailing in the circumnuclear disk. Another high…
Chandra X-ray Observatory grating spectra of the supergiant X-ray Binary 4U 1700-37 reveal emission lines from hydrogen and helium-like S, Si, Mg, and Ne in the 4-13 A range. The spectrum also shows fluorescent lines from S, Si, and a…
During its 2005 outburst, GRO J1655-40 was observed twice with the Chandra High Energy Transmission Grating Spectrometer; the second observation revealed a spectrum rich with ionized absorption lines from elements ranging from O to Ni…
We present the first high-resolution X-ray spectrum of the Seyfert 1.5 galaxy NGC 4151. Observations with the Chandra High Energy Transmission Grating Spectrometer reveal a spectrum dominated by narrow emission lines from a spatially…
We present an analysis of ionized X-ray disk winds observed in the Fe K band of four stellar-mass black holes observed with Chandra, including 4U 1630-47, GRO J1655-40, H 1743-322, and GRS 1915+105. High-resolution photoionization grids…
We present a preliminary analysis of the first high-resolution X-ray spectrum of a Seyfert 2 galaxy, Mkn 3, obtained with the High Energy Transmission Grating Spectrometer onboard the Chandra X-ray Observatory. The high-energy spectrum…
We present results from ${\it NuSTAR}$ and ${\it SWIFT}$/XRT joint spectral analysis of V4641 Sgr during a disk dominated or soft state as well as a powerlaw dominated or hard state. The soft state spectrum is well modeled by a…
We have simultaneously fit Chandra and RXTE spectra of the Galactic black hole XTE J1118+480 with three models for X-ray reflection. We explored a range of accretion disc ionizations (log(xi)=1-4; xi=L_X/nR^{2}) and iron abundances…
The black hole X-ray binary V4641 Sgr experienced an outburst in 2002 May which was detected at X-ray, optical, and radio wavelengths. The outburst lasted for only 6 days, but the object remained active for the next several months. Here we…
We present seven separate Chandra observations of the 2001 superoutburst of WZ Sge. The high-energy outburst was dominated by intense EUV emission lines, which we interpret as boundary layer emission scattered into our line of sight in an…