Search Publications
The universal galaxy cluster pressure profile from a representative sample of nearby systems (REXCESS) and the YSZ - M500 relation
Böhringer, H.; Arnaud, M.; Pointecouteau, E. +3 more
We investigate the regularity of cluster pressure profiles with REXCESS, a representative sample of 33 local (z < 0.2) clusters drawn from the REFLEX catalogue and observed with XMM-Newton. The sample spans a mass range of 1014 M⊙ < M500 < 1015 M⊙, where M500 is the mass co…
Evidence for ultra-fast outflows in radio-quiet AGNs. I. Detection and statistical incidence of Fe K-shell absorption lines
Cappi, M.; Dadina, M.; Tombesi, F. +4 more
Context. Blue-shifted Fe K absorption lines have been detected in recent years between 7 and 10 keV in the X-ray spectra of several radio-quiet AGNs. The derived blue-shifted velocities of the lines can often reach mildly relativistic values, up to 0.2-0.4c. These findings are important because they suggest the presence of a previously unknown mas…
The X-ray to optical-UV luminosity ratio of X-ray selected type 1 AGN in XMM-COSMOS
Le Floc'h, E.; Jahnke, K.; Salvato, M. +29 more
We present a study of the X-ray to optical properties of a sample of 545 X-ray selected type 1 AGN, from the XMM-COSMOS survey, over a wide range of redshifts (0.04 < z < 4.25) and X-ray luminosities (40.6 ≤ Log L[2-10]~keV ≤ 45.3). About 60% of them are spectroscopically identified type 1 AGN, while the others have a reliable pho…
Gas entropy in a representative sample of nearby X-ray galaxy clusters (REXCESS): relationship to gas mass fraction
Böhringer, H.; Arnaud, M.; Pratt, G. W. +6 more
We examine the radial entropy distribution and its scaling using 31 nearby galaxy clusters from the representative XMM-Newton cluster structure survey (REXCESS), a sample in the temperature range 2-9 keV selected in X-ray luminosity only, with no bias toward any particular morphological type. The entropy profiles are robustly measured at least out…
First detection of VHE γ-rays from SN 1006 by HESS
Klochkov, D.; Santangelo, A.; Quirrenbach, A. +178 more
Aims: Recent theoretical predictions of the lowest very high energy (VHE) luminosity of SN 1006 are only a factor 5 below the previously published HESS upper limit, thus motivating further in-depth observations of this source.
Methods: Deep observations at VHE energies (above 100 GeV) were carried out with the high energy stereoscopic sy…
Mass profiles and c-MDM relation in X-ray luminous galaxy clusters
Rossetti, M.; Molendi, S.; Gastaldello, F. +4 more
Context. Galaxy clusters represent valuable cosmological probes using tests that mainly rely on measurements of cluster masses and baryon fractions. X-ray observations represent one of the main tools for uncovering these quantities.
Aims: We aim to constrain the cosmological parameters Ωm and σ8 using the observed distri…
FERO: Finding extreme relativistic objects. I. Statistics of relativistic Fe Kα lines in radio-quiet Type 1 AGN
Bianchi, S.; Cappi, M.; Ponti, G. +10 more
Context. Accretion models predict that fluorescence lines broadened by relativistic effects should arise from reflection of X-ray emission onto the inner region of the accretion disc surrounding the central black hole of active galactic nuclei (AGN). The theory behind the origin of relativistic lines is well established, and observational evidence…
Substructure of the galaxy clusters in the REXCESS sample: observed statistics and comparison to numerical simulations
Böhringer, H.; Arnaud, M.; Pratt, G. W. +6 more
We study the substructure statistics of a representative sample of galaxy clusters by means of two currently popular substructure characterisation methods, power ratios and centroid shifts. We use the 31 clusters from the REXCESS sample, compiled from the southern ROSAT All-Sky cluster survey (REFLEX) with a morphologically unbiased selection in X…
Coronal properties of planet-bearing stars
Schmitt, J. H. M. M.; Robrade, J.; Poppenhaeger, K.
Context. Do extrasolar planets affect the activity of their host stars? Indications for chromospheric activity enhancement have been found for a handful of targets, but in the X-ray regime, conclusive observational evidence is still missing.
Aims: We want to establish a sound observational basis to confirm or reject major effects of Star-Plan…
Cold fronts in galaxy clusters
Rossetti, M.; Molendi, S.; Ghizzardi, S.
Context. Cold fronts have been observed in several galaxy clusters. Understanding their nature and origin is extremely important for investigating the internal dynamics of clusters.
Aims: To gain insight into the nature of these features, we carry out a statistical investigation of their occurrence in a sample of galaxy clusters observed with…