Search Publications
Constructing a Galactic coordinate system based on near-infrared and radio catalogs
Zhu, Z.; Liu, J. -C.; Hu, B.
Context. The definition of the Galactic coordinate system was announced by the IAU Sub-Commission 33b on behalf of the IAU in 1958. An unrigorous transformation was adopted by the Hipparcos group to transform the Galactic coordinate system from the FK4-based B1950.0 system to the FK5-based J2000.0 system or to the International Celestial Reference…
Broad iron emission lines in Seyfert galaxies - re-condensation of gas onto an inner disk below the ADAF?
Meyer, F.; Meyer-Hofmeister, E.
Context. The number of strong iron Kα line detections in Seyfert AGN is clearly growing in the Chandra, XMM-Newton and Suzaku era. The iron emission lines are broad, some are relativistically blurred. These relativistic disk lines have also been observed for galactic black hole X-ray binaries. Thermal components found in hard spectra we…
Gas temperature profiles in galaxy clusters with Swift XRT: observations and capabilities to map near R200
Moretti, A.; Molendi, S.; Gastaldello, F. +1 more
Aims: We investigate the possibility of using the X-ray telescope (XRT) on board the Swift satellite to improve the current accuracy of the intra-cluster medium (ICM) temperature measurements in the region close to the virial radius of nearby clusters.
Methods: We present the spectral analysis of the Swift XRT observations of 6 galaxy cl…
Discovery of the correspondence between intra-cluster radio emission and a high pressure region detected through the Sunyaev-Zel'dovich effect
Croston, J. H.; Bourdin, H.; Mazzotta, P. +9 more
We analyzed new 237 MHz and 614 MHz GMRT data of the most X-ray luminous galaxy cluster, RX J1347-1145. Our radio results are compared with the MUSTANG 90 GHz Sunyaev-Zel'dovich effect map and with re-processed Chandra and XMM-Newton archival data of this cluster. We point out for the first time in an unambiguous way the correspondence between a r…
An optical/NIR survey of globular clusters in early-type galaxies. I. Introduction and data reduction procedures
Larsen, S. S.; Kuntschner, H.; Chies-Santos, A. L. +3 more
Context. The combination of optical and near-infrared (NIR) colours has the potential to break the age/metallicity degeneracy and offers a better metallicity sensitivity than optical colours alone. Previous tudies of extragalactic globular clusters (GCs) with this colour combination, however, have suffered from small samples or have been restricte…
Thermal properties of the asteroid (2867) Steins as observed by VIRTIS/Rosetta
Erard, S.; Drossart, P.; Capaccioni, F. +6 more
Context. To investigate thermal properties of the small asteroid (2867) Steins, we analyzed its surface thermal emission measured by the VIRTIS instrument during the Rosetta spacecraft (ESA) flyby that occurred in September 2008. VIRTIS performed the first thermal mapping of an asteroid surface.
Aims: We determine the thermal properties of di…
A stringent upper limit to SO2 in the Martian atmosphere
Forget, F.; Encrenaz, T.; Atreya, S. K. +6 more
Surfur-bearing molecules have been found at the surface of Mars by the Viking lander, the Spirit and Opportunity rovers, and the OMEGA infrared spectrometer aboard Mars Express. However, no gaseous sulfur-bearing species have ever been detected in the Martian atmosphere. We search for SO2 signatures in the thermal spectrum of Mars at 7.…
Temperature variability in X-ray bright points observed with Hinode/XRT
Kariyappa, R.; Damé, L.; Golub, L. +4 more
Aims: We investigate the variability in temperature as a function of time among a sample of coronal X-ray bright points (XBPs).
Methods: We analysed a 7-h (17:00-24:00 UT) long time sequence of soft X-ray images observed almost simultaneously in two filters (Ti_poly and Al_mesh) on April 14, 2007 with X-ray telescope (XRT) onboard the Hi…
Molecular gas in NUclei of GAlaxies (NUGA). XV. Molecular gas kinematics in the inner 3 kpc of NGC 6951
Schinnerer, E.; Baker, A. J.; Combes, F. +6 more
Within the NUclei of GAlaxies (NUGA) project we have obtained IRAM PdBI and 30 m 12CO(1-0) and 12CO(2-1) observations of the spiral galaxy NGC 6951. Previous work shows that there is indirect evidence of gas inflow from 3 kpc down to small radii: a large-scale stellar bar, a prominent starburst ring (r ≈ 580 pc) and a LINER/S…
Intensity contrast from MHD simulations and HINODE observations
Solanki, S. K.; Lagg, A.; Schüssler, M. +3 more
Context. Changes in the solar surface area, which is covered by small-scale magnetic elements, are thought to cause long-term changes in the solar spectral irradiance, which are important for determining the impact on Earth's climate.
Aims: To study the effect of small-scale magnetic elements on the total and spectral irradiance, we derive th…