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Chandra LETGS spectroscopy of the Quasar MR2251-178 and its warm absorber
J. M. Ramírez, S. Komossa, V. Burwitz +1
We present an analysis of our Chandra Low Energy Transmission Grating Spectrometer (LETGS) observation of the quasar MR2251-178. The warm absorber of MR2251-178 is well described b…
Variability in the cycle length of the supersoft source RX J0513.9-6951
V. Burwitz, K. Reinsch, J. Greiner +4
The supersoft X-ray binary RX J0513.9-6951 shows cyclic changes between optical-low / X-ray-on states and optical-high / X-ray-off states. It is supposed to be accreting close to t…
A deep Large Binocular Telescope view of the Canes Venatici I dwarf galaxy
Nicolas F. Martin, Matthew G. Coleman, Jelte T. A. De Jong +13
We present the first deep color-magnitude diagram of the Canes Venatici I (CVnI) dwarf galaxy from observations with the wide field Large Binocular Camera on the Large Binocular Te…
M31N 2005-09c: a fast FeII nova in the disk of M31
D. Hatzidimitriou, P. Reig, A. Manousakis +3
Classical novae are quite frequent in M~31. However, very few spectra of M31 novae have been studied to date, especially during the early decline phase. Our aim is to study the pho…
Multiwavelength appearance of Vela Jr.: Is it up to expectations?
A. F. Iyudin, B. Aschenbach, V. Burwitz +4
Vela Jr. is one of the youngest and likely nearest among the known galactic supernova remnants (SNRs). Discovered in 1997 it has been studied since then at quite a few wavelengths,…
XMM-Newton observation of the long-period polar V1309 Ori: The case for pure blobby accretion
R. Schwarz, K. Reinsch, K. Beuermann +1
Using XMM-Newton we have obtained the first X-ray observation covering a complete orbit of the longest period polar, V1309 Ori. The X-ray light curve is dominated by a short, brigh…
New Gamma-Ray Probe of the Baryonic Dark Matter
A. F. Iyudin, V. Burwitz, J. Greiner +2
We expand on the recently reported detections of the gamma-ray resonant absorption along the line of sight toward gamma-ray bright quasars (QSOs), like 3C279. We propose to use thi…
Multifrequency Observations of the Gamma-Ray Blazar 3C 279 in Low-State during Integral AO-1
W. Collmar, M. Böttcher, V. Burwitz +19
We report first results of a multifrequency campaign from radio to hard X-ray energies of the prominent gamma-ray blazar 3C 279 during the first year of the INTEGRAL mission. The v…
Improving XMM-Newton EPIC pn data at low energies: method and application to the Vela SNR
Konrad Dennerl, Bernd Aschenbach, Ulrich G. Briel +13
High quantum efficiency over a broad spectral range is one of the main properties of the EPIC pn camera on-board XMM-Newton. The quantum efficiency rises from ~75% at 0.2 keV to ~1…
Chandra Observations of the NLS1 RX J2217.9-5941
D. Grupe, K. M. Leighly, V. Burwitz +2
We report the results of two Chandra ACIS-S observations from February and August 2003 of the highly X-ray variable Narrow-Line Seyfert 1 galaxy RX J2217.9--5941. Observations span…
On the Nature of the Binary Components of RX J0806.3+1527
K. Reinsch, V. Burwitz, R. Schwarz
We present imaging circular polarimetry and near-infrared photometry of the suspected ultra-short period white-dwarf binary RX J0806.3+1527 obtained with the ESO VLT and discuss th…
A Chandra LETGS observation of V4743 Sagittarius: A Super Soft X-ray Source and a Violently Variable Light Curve
J. -U. Ness, S. Starrfield, V. Burwitz +13
V4743 Sgr (Nova Sgr 2002 No. 3) was discovered on 20 September 2002. We obtained a 5ks ACIS-S spectrum in November 2002 and found that the nova was faint in X-rays. We then obtaine…
Strange Quark Matter in Neutron Stars? - New Results from Chandra and XMM
Markus H. Thoma, Joachim Truemper, Vadim Burwitz
It has been predicted that quark and hybrid stars, containing strange quark matter in their core, have a significantly smaller radius than ordinary neutron stars. Preliminary X-ray…
Discovery of a binary AGN in the ultraluminous infrared galaxy NGC 6240 using Chandra
Stefanie Komossa, Vadim Burwitz, Guenther Hasinger +3
Ultraluminous infrared galaxies (ULIRGs) are outstanding due to their huge luminosity output in the infrared, which is predominantly powered by super starbursts and/or hidden activ…
The thermal radiation of the isolated neutron star RX J1856.5-3754 observed with Chandra and XMM-Newton
V. Burwitz, F. Haberl, R. Neuhaeuser +3
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 m…
1ES 1927+654: Persistent and rapid X-ray variability in an AGN with low intrinsic neutral X-ray absorption and narrow optical emission lines
Th. Boller, W. Voges, M. Dennefeld +7
We present X-ray and optical observations of the X-ray bright AGN 1ES 1927+654. The X-ray observations obtained with ROSAT and Chandra reveal persistent, rapid and large scale vari…
X-ray Spectrum and Pulsations of the Vela Pulsar
D. Sanwal, G. G. Pavlov, O. Y. Kargaltsev +5
We report the results of the spectral and timing analysis of observations of the Vela pulsar with the Chandra X-ray Observatory. The spectrum shows no statistically significant spe…
The joint XMM-Newton and Chandra view of YY Gem
B. Stelzer, V. Burwitz, R. Neuhaeuser +2
We have observed the flare star YY Gem simultaneously with XMM-Newton and Chandra as part of a multi-wavelength campaign aiming at a study of variability related to magnetic activi…
CHANDRA observation of the narrow-line Seyfert 1 galaxy IRAS 13224-3809
F. Pfefferkorn, Th. Boller, V. Burwitz +1
The narrow-line Seyfert 1 galaxy (NLS1) IRAS 13224-3809 has been observed with the CHANDRA High Resolution Camera (HRC-I) for 12 ksec on February, 2, 2000. The source was proposed…
RX J1313.2-3259, a long-period Polar discovered with ROSAT
H. -C. Thomas, K. Beuermann, V. Burwitz +2
We report observations of a new AM Herculis binary identified as the optical counterpart of the X-ray source RX J1313.2-3259, detected during the ROSAT All-Sky Survey (RASS). It ha…
Optical observations of the black hole candidate XTE J1550-564 during the Sep/Oct 1998 outburst
C. Sanchez-Fernandez, A. J. Castro-Tirado, H. W. Duerbeck +11
We report here optical observations during the September/October 1998 outburst of the black hole candidate XTE J1550-564. CCD photometry was obtained for the optical counterpart wi…
RX J0501.7-0359: a new ROSAT discovered eclipsing polar in the period gap
Vadim Burwitz, Klaus Reinsch, Klaus Beuermann +1
RXJ 0501.7-0359 is a new V ~ 17 mag eclipsing polar discovered during the ROSAT all-sky survey (RASS). Extensive follow-up observations at X-ray (pointed ROSAT PSPC and HRI observa…