Search Publications
In-flight calibration of the ISGRI camera
Goldoni, P.; Malaguti, G.; David, P. +12 more
ISGRI, the IBIS low energy camera (15 keV-1 MeV) on board INTEGRAL, is the first large CdTe gamma-ray imager in orbit. We present here an overview of the ISGRI in-flight calibrations performed during the first months after launch. We discuss the stability of the camera as well as the CdTe pixels response under cosmic radiation. The energy calibrat…
The central engines of radio-loud quasars
Ho, L. C.; Staubert, R.; Wang, J. -M.
We have assembled a sample of 37 radio-loud quasars that have been imaged with the Hubble Space Telescope in order to investigate their black hole masses, accretion rates, and the structure of their accretion disks. The black hole masses were estimated from the luminosities of the host galaxies, and the accretion powers were extrapolated from the …
The nature of the prompt X-ray and radio emission from SN 2002ap
Ray, A.; Bhatnagar, S.; Chandra, P. +1 more
We report on the combined X-ray and radio observations of the type Ic SN 2002ap, using XMM-Newton TOO observation of M 74 and the Giant Metrewave Radio Telescope (GMRT). We account for the presence of a nearby source in the pre-supernova Chandra field of view in our measurements of the X-ray flux (0.3 - 10 KeV) 5.2 days after the explosion. The X-…
XMM-Newton light curves of the low-mass X-ray binary EXO 0748-676: Dips, eclipses, and bursts
Wijnands, R.; van den Berg, M.; Homan, J.
We present an analysis of XMM-Newton light curves of the dipping, bursting, and eclipsing low-mass X-ray binary EXO 0748-676, focusing on the variability on time scales of seconds to hours. The observed variability can be roughly divided in three types: dips, eclipses and bursts. We find that the appearance of the latter two, depends strongly on t…
Explanatory supplement of the ISOGAL-DENIS Point Source Catalogue
Alard, C.; Blommaert, J. A. D. L.; Ganesh, S. +10 more
We present version 1.0 of the ISOGAL-DENIS Point Source Catalogue (PSC), containing more than 100 000 point sources detected at 7 and/or 15 mu m in the ISOGAL survey of the inner Galaxy with the ISOCAM instrument on board the Infrared Space Observatory (ISO). These sources are cross-identified, wherever possible, with near-infrared (0.8-2.2 mu m) …
XMM-Newton observation of the ULIRG NGC 6240. The physical nature of the complex Fe K line emission
Costantini, E.; Hasinger, G.; Boller, Th. +5 more
We report on an XMM-Newton observation of the ultraluminous infrared galaxy NGC 6240. The 0.3-10 keV spectrum can be successfully modelled with: (i) three collisionally ionized plasma components with temperatures of about 0.7, 1.4, and 5.5 keV; (ii) a highly absorbed direct power-law component; and (iii) a neutral Fe Kalpha and Kbeta line. We dete…
A simple analytical expression for the power spectrum of cascading Alfvén waves in the solar wind
Laitinen, T.; Fichtner, H.; Vainio, R.
Alfvén wave transport in the solar wind, including non-linear spectral energy transfer, is studied. We present numerical solutions of wave transport using a diffusive flux function previously introduced for spectral energy transfer, and compare it with the analytical solution obtained for a convective flux function. The two models of cascading pro…
Plasma properties above coronal active regions inferred from SOHO/UVCS and radio spectrograph observations
Raymond, J. C.; Wu, R.; Kohl, J. +3 more
Information on coronal plasma was inferred from the joint analysis of type {II} radio bursts and SOHO UltraViolet Coronagraph Spectrometer (UVCS) observations. The data sample comprises 37 metric type {II} radio bursts observed by ground-based radio spectrographs in 1999, during the rising phase of the solar cycle. The coronal electron densities n…
Hipparcos red stars in the HpVT2 and VIC systems
Makarov, V. V.; Berdnikov, L. N.; Lebzelter, T. +6 more
For Hipparcos M, S, and C spectral type stars, we provide calibrated instantaneous (epoch) Cousins V - I color indices using newly derived HpVT2 photometry. Three new sets of ground-based Cousins VI data have been obtained for more than 170 carbon and red M giants. These datasets in combination with the published sources of V…
Near-IR spectra of ISOGAL sources in the inner Galactic Bulge
Omont, A.; Schultheis, M.; Ojha, D. K. +2 more
We present near-IR spectra (HK-band) of a sample of 107 sources with mid-IR excesses at 7 and 15;mu m detected during the ISOGAL survey. Making use of the DENIS interstellar extinction map from Schultheis et al. (1999) we derive luminosities and find that the Mbol vs. 12CO and M_bol vs. H2O diagrams are powerful to…