Related papers: Is CGCS 5926 a symbiotic X-ray binary?
We have carried out an in-depth study of low-mass X-ray binaries (LMXBs) detected in the nearby lenticular galaxy NGC 3115, using the Megasecond Chandra X-Ray Visionary Project observation (total exposure time 1.1 Ms). In total we found 136…
Context: The Mira variable LX Cyg showed a dramatic increase of its pulsation period in the recent decades and appears to undergo an important transition in its evolution. Aims: We aim at investigating the spectral type evolution of this…
We present X-ray and optical observations of a new transient X-ray source in M31 first detected 23-May-2004 at R.A.=00:43:09.940 +/- 0.65'', Dec.=41:23:32.49 +/- 0.66''. The X-ray lightcurve shows two peaks separated by several months,…
We report on the spectroscopic monitoring of GCIRS16SW, an Ofpe/WN9 star and LBV candidate in the central parsec of the Galaxy. SINFONI observations show strong daily spectroscopic changes in the K band. Radial velocities are derived from…
The properties of the early-type binary Cyg OB2 #5 have been debated for many years and spectroscopic and photometric investigations yielded conflicting results. We have attempted to constrain the physical properties of the binary by…
We use K-band spectroscopy of the counterpart to the rapidly variable X-ray transient XMMU J174445.5-295044 to identify it as a new symbiotic X-ray binary. XMMU J174445.5-295044 has shown a hard X-ray spectrum (we verify its association…
As part of a reanalysis of galactic Asymptotic Giant Branch (AGB) stars at infrared (IR) wavelengths, we discuss a sample (357) of carbon stars for which mass loss rates, near-IR photometry and distance estimates exist. For 252 sources we…
On 2008 May 14, the Burst Alert Telescope aboard the Swift mission triggered on a type-I X-ray burst from the previously unclassified ROSAT object 1RXH J173523.7-354013, establishing the source as a neutron star X-ray binary. We report on…
We present a comprehensive analysis of the optical and infrared (IR) properties of high-mass X-ray binary (HMXB) IC 10 X-2, classified as a super-giant HMXB and super-fast X-ray transient (SFXT) by previous work. Our analysis of regular…
We report optical and infrared observations of the X-ray source CXOGBS J174623.5-310550. This Galactic object was identified as a potential quiescent low-mass X-ray binary accreting from an M-type donor on the basis of optical spectroscopy…
We present an analysis of the Swift BAT and XRT data of GRB060602B, which is most likely an accreting neutron star in a binary system and not a gamma-ray burst. Our analysis shows that the BAT burst spectrum is consistent with a…
Although dwarf carbon (dC) stars are thought universally to be binaries to explain the presence of $C_2$ in their spectra while still near main sequence luminosity, direct observational evidence for binarity is remarkably scarce. Here we…
Two different models have been put forward to explain the origin of the X-ray emission of the unusual X-ray source 1E 1024.0-5732/Wack 2134: a high-mass X-ray binary system (HMXB) and a colliding wind binary (CWB). We present new optical…
The central $2\times0.8$ deg$^2$ region of our Galaxy contains $\sim10,000$ X-ray point sources that were detected by a series of Chandra observations over the last two decades. However, the limited bandpass of Chandra below 8 keV hampered…
We report on analysis of X-ray, optical and radio observations of the previously overlooked X-ray source 2CXO\,J174517.0$-$321356 located just 3.2$^{\circ}$ away from the Galactic center. Timing analysis of X-ray observations of the source…
We report discovery of a compact object at high Galactic latitude. The object was initially identified as a ROSAT All-Sky Survey Bright Source Catalog X-ray source, 1RXS J141256.0+792204, statistically likely to possess a high X-ray to…
We obtained an optical spectrum of a star we identify as the optical counterpart of the M31 Chandra source CXO J004318.8+412016, because of prominent emission lines of the Balmer series, of neutral helium, and a He II line at 4686 Angstrom.…
The last comprehensive catalogue of high-mass X-ray binaries in the Small Magellanic Cloud (SMC) was published about ten years ago. Since then new such systems were discovered, mainly by X-ray observations with Chandra and XMM-Newton. For…
The Chandra X-ray Observatory (CXO) imaged the high-mass gamma-ray binary (HMGB) HESS J0632+057 with the Advanced CCD Imaging Spectrometer (ACIS). We analyzed the CXO data together with 967 ks of archival Swift-XRT observations. On…
As main-sequence stars with C$>$O, dwarf carbon (dC) stars are never born alone but inherit carbon-enriched material from a former asymptotic giant branch (AGB) companion. In contrast to M dwarfs in post-mass transfer binaries, C$_2$ and/or…