Search Publications
Two formation channels of ultra-compact dwarf galaxies in Hickson compact groups
Mendes de Oliveira, C.; Hilker, M.; Ziegler, B. L. +3 more
Context. The formation of ultra-compact dwarf galaxies (UCDs) is believed to be driven by interaction, and UCDs are abundant in the cores of galaxy clusters, environments that mark the end-point of galaxy evolution. Nothing is known about the properties of UCDs in compact groups of galaxies, environments where most of galaxy evolution and interact…
Radial profiles of Fe abundance in the intracluster medium of nearby clusters observed with XMM-Newton
Matsushita, K.
Aims: The abundances of Fe in the intracluster medium of nearby (z < 0.08) clusters were measured up to 0.3 ~ 0.5r180.
Methods: We analyzed 28 clusters of galaxies observed with XMM-Newton. We derived Fe abundances from the flux ratios of Fe lines to the continuum within an energy range of 3.5-6 keV to minimize and evaluate…
Image reconstruction in optical interferometry: benchmarking the regularization
Thiébaut, E.; Malbet, F.; Renard, S.
Context. With the advent of visible and infrared long-baseline interferometers with more than two telescopes, both the size and the completeness of interferometric data sets have significantly increased, allowing images based on models with no a priori assumptions to be reconstructed with an aperture synthesis technique.
Aims: Our main object…
GRB 091127/SN 2009nz and the VLT/X-shooter spectroscopy of its host galaxy: probing the faint end of the mass-metallicity relation
Covino, S.; D'Avanzo, P.; Sánchez-Ramírez, R. +36 more
We perform a detailed study of the gamma-ray burst GRB 091127/SN 2009nz host galaxy at z = 0.490 using the VLT/X-shooter spectrograph in slit and integral-field unit (IFU) mode. From the analysis of the optical and X-ray afterglow data obtained from ground-based telescopes and Swift-XRT, we confirm the presence of a bump associated with SN 2009nz …
XMM-Newton observations of IGR J18410-0535: the ingestion of a clump by a supergiant fast X-ray transient
Campana, S.; Cusumano, G.; Israel, G. +6 more
Context. IGR J18410-0535 is a supergiant fast X-ray transients. This subclass of supergiant X-ray binaries typically undergoes few-hour-long outbursts reaching luminosities of 1036-1037 erg s-1, the occurrence of which has been ascribed to the combined effect of the intense magnetic field and rotation of the compac…
About the p-mode frequency shifts in HD 49933
García, R. A.; Mathur, S.; Ballot, J. +2 more
We study the frequency dependence of the frequency shifts of the low-degree p modes measured in the F5V star HD 49933, by analyzing the second run of observations collected by the CoRoT satellite. The 137-day light curve is divided into two subseries corresponding to periods of low and high stellar activity. The activity-frequency relationship is …
1ES 0229+200: an extreme blazar with a very high minimum Lorentz factor
Tibolla, O.; Hauser, M.; Wagner, S. J. +1 more
The blazar 1ES 0229+200 is a high-frequency-peaked BL Lac object with a hard TeV spectrum extending to 10TeV. Its unusual spectral characteristics make it a frequently used probe for intergalactic radiation and magnetic fields. With new, simultaneous observations in the optical, ultraviolet (UV), and X-rays, the synchrotron emission is probed in g…
Far-infrared to millimeter astrophysical dust emission. II. Comparison of the two-level systems (TLS) model with astronomical data
Bernard, J. -P.; Paradis, D.; Mény, C. +1 more
Aims: In a previous paper we proposed a new model for the emission by amorphous astronomical dust grains, based on solid-state physics. The model uses a description of the disordered charge distribution (DCD) combined with the presence of two-level systems (TLS) defects in the amorphous solid composing the grains. The goal of this paper is to…
The broad iron Kα line of Cygnus X-1 as seen by XMM-Newton in the EPIC-pn modified timing mode
Reynolds, C. S.; Nowak, M. A.; Dauser, T. +7 more
We present the analysis of the broadened, flourescent iron Kα line in simultaneous XMM-Newton and RXTE data from the black hole Cygnus X-1. The XMM-Newton data were taken in a modified version of the timing mode of the EPIC-pn camera. In this mode the lower energy threshold of the instrument is increased to 2.8 keV to avoid telemetry drop outs due…
Back and forth from cool core to non-cool core: clues from radio halos
Rossetti, M.; Molendi, S.; Gastaldello, F. +3 more
X-ray astronomers often divide galaxy clusters into two classes: "cool core" (CC) and "non-cool core" (NCC) objects. The origin of this dichotomy has been the subject of debate in recent years, between "evolutionary" models (where clusters can evolve from CC to NCC, mainly through mergers) and "primordial" models (where the state of the cluster is…