Search Publications
The isolated neutron star RBS1774 revisited. Revised XMM-Newton X-ray parameters and an optical counterpart from deep LBT-observations
Steinmetz, M.; Fontana, A.; Giallongo, E. +12 more
We report optical B-band observations with the Large Binocular Telescope (LBT) of the isolated neutron star RBS1774. The stacked image with a total exposure of 2fh5 reveals a candidate optical counterpart at mB = 26.96 ± 0.20 at position α (2000) = 21^h43^m03fs40, δ(2000) = +06degr54^prime17farcs5, within the joint Chandra and XMM-Newto…
An X-ray spectral survey of the disc of M 31 with XMM-Newton
Kolb, U.; Osborne, J. P.; Barnard, R. +2 more
Aims: We present the results of a complete spectral survey of the X-ray point sources detected in five XMM-Newton observations along the major axis of M 31 but avoiding the central bulge, aimed at establishing the population characteristics of X-ray sources in this galaxy.
Methods: We obtained background subtracted spectra and lightcurves for …
On the inverse Compton scattering interpretation of the hard X-ray excesses in galaxy clusters: the case of Ophiuchus
Colafrancesco, S.; Marchegiani, P.
Context: Populations of high energy electrons can produce hard X-ray (HXR) emission in galaxy clusters by up-scattering CMB photons via the inverse Compton scattering (ICS) mechanism. However, this scenario has various astrophysical consequences.
Aims: We discuss here the consequences of the presence of a population of high energy particles fo…
Determination of the cosmic far-infrared background level with the ISOPHOT instrument
Juvela, M.; Lemke, D.; Klaas, U. +3 more
Context: The cosmic infrared background (CIRB) consists mainly of the integrated light of distant galaxies. In the far-infrared the current estimates of its surface brightness are based on the measurements of the COBE satellite. Independent confirmation of these results is still needed from other instruments.
Aims: In this paper we derive esti…
Nuclear interaction gamma-ray lines from the Galactic center region
Cheng, K. S.; Ip, W. H.; Tatischeff, V. +3 more
Aims. The accretion of stars onto the central supermassive black hole at the center of the Milky Way is predicted to generate large fluxes of subrelativistic ions in the Galactic center region. We analyze the intensity, shape, and spatial distribution of de-excitation gamma-ray lines produced by nuclear interactions of these energetic particles wi…
MAGIC upper limits to the VHE gamma-ray flux of 3C 454.3 in high emission state
Maraschi, L.; Covino, S.; Antonelli, L. A. +146 more
Aims: We report upper limits to the very high energy flux (E>100 GeV) of the flat spectrum radio quasar 3C 454.3 (z=0.859) derived by the Cherenkov telescope MAGIC during the high states of July/August and November/December 2007. We compare the upper limits derived in both time slots with the available quasi-simultaneous MeV-GeV data from the A…
INTEGRAL and XMM-Newton observations of AX J1845.0-0433
Walter, R.; Zurita Heras, J. A.
Aims: AX J1845.0-0433 is a transient high-mass X-ray binary discovered by ASCA. The source displays bright and short flares observed by INTEGRAL. The transient behaviour and bright and short flares are studied to understand both the accretion mechanisms and nature of the source.
Methods: Public INTEGRAL data and a pointed XMM-Newton observatio…
The plasma filling factor of coronal bright points. II. Combined EIS and TRACE results
Dere, K. P.
Aims: In a previous paper, the volumetric plasma filling factor of coronal bright points was determined from spectra obtained with the Extreme ultraviolet Imaging Spectrometer (EIS). The analysis of these data showed that the median plasma filling factor was 0.015. One interpretation of this result was that the small filling factor was consistent …
The spectroscopically confirmed huge cosmic structure at z = 0.55
Finoguenov, A.; Tanaka, M.; Koyama, Y. +3 more
We report on the spectroscopic confirmation of a huge cosmic structure around the CL0016 cluster at z=0.55. We made wide-field imaging observations of the surrounding regions of the cluster and identified more than 30 concentrations of red galaxies near the cluster redshift. The follow-up spectroscopic observations of the most prominent part of th…
A dam around the Water Fountain Nebula?. The dust shell of IRAS16342-3814 spatially resolved with VISIR/VLT
Waters, L. B. F. M.; Peletier, R. F.; Verhoelst, T. +4 more
Context: Bipolar morphologies in planetary nebulae (PNe) are believed to be closely linked to binary central stars. Either by collimating a fast stellar wind or by driving a jet via accretion in the central system, dusty torii or stable disks may be crucial ingredients for the shaping of PNe.
Aims: We study the dust distribution in the very yo…