Search Publications
Density of neutral interstellar hydrogen at the termination shock from Ulysses pickup ion observations
Möbius, E.; Bzowski, M.; Gloeckler, G. +2 more
Aims: By reevaluating a 13-month stretch of Ulysses SWICS H pickup ion measurements near 5 AU close to the ecliptic right after the previous solar minimum, this paper presents a determination of the neutral interstellar H density at the solar wind termination shock and implications for the density and ionization degree of hydrogen in the local int…
High precision X-ray log N - log S distributions: implications for the obscured AGN population
Treister, E.; Ebrero, J.; Page, M. J. +13 more
Context: Our knowledge of the properties of AGN, especially those of optical type-2 objects, is very incomplete. Because extragalactic source count distributions are dependent on the cosmological and statistical properties of AGN, they provide a direct method of investigating the underlying source populations.
Aims: We aim to constrain the ext…
XMM-Newton observations of the supernova remnant IC 443. II. Evidence of stellar ejecta in the inner regions
Troja, E.; Miceli, M.; Bocchino, F. +1 more
Aims: We investigate the spatial distribution of the physical and chemical properties of the hot X-ray emitting plasma of the supernova remnant IC 443, to derive important constraints on its ionization stage, on the progenitor supernova explosion, on the age of the remnant, and its physical association with a close pulsar wind nebula.
Methods:…
XMM-Newton observations of the Lockman Hole: X-ray source catalogue and number counts
Cappelluti, N.; Barcons, X.; Fabian, A. C. +4 more
Context: The Lockman Hole field represents the sky area of lowest Galactic line-of-sight column density N_H=5.7 × 1019 cm-2. It was observed by the XMM-Newton X-ray observatory in 18 pointings for a total of 1.16 Ms (raw EPIC pn observing time) constituting the deepest XMM-Newton exposure so far. After the removal of time int…
Unveiling the nature of six HMXBs through IR spectroscopy
Mennickent, R. E.; Fabregat, J.; Nespoli, E.
Context: The International Gamma-Ray Astrophyiscs Laboratory (INTEGRAL) is discovering a large number of new hard X-ray sources, many of them being HMXBs. The identification and spectral characterization of their optical/infrared counterparts is a necessary step to undertake detailed study of these systems. In particular, the determination of the …
Exploring a SNR/molecular cloud association within HESS J1745-303
Santangelo, A.; Ripken, J.; Carrigan, S. +139 more
Aims: HESS J1745-303 is an extended, unidentified VHE (very high energy) gamma-ray source discovered using HESS in the Galactic Plane Survey. Since no obvious counterpart has previously been found in longer-wavelength data, the processes that power the VHE emission are not well understood.
Methods: Combining the latest VHE data with recent XMM…
Direct evidence of a sub-stellar companion around CT Chamaeleontis
Neuhäuser, R.; Schmidt, T. O. B.; Hauschildt, P. H. +5 more
Aims: In our ongoing search for close and faint companions around T Tauri stars in the Chamaeleon star-forming region, we here present observations of a new common proper motion companion to the young T-Tauri star and Chamaeleon member CT Cha and discuss its properties in comparison to other young, low-mass objects and to synthetic model spectra f…
Testing the inverse-Compton catastrophe scenario in the intra-day variable blazar S5 0716+71. III. Rapid and correlated flux density variability from radio to sub-mm bands
Grewing, M.; Britzen, S.; Wagner, S. J. +22 more
Aims: The BL Lac object S5 0716+71 was observed in a global multi-frequency campaign to search for rapid and correlated flux density variability and signatures of an inverse-Compton (IC) catastrophe during the states of extreme apparent brightness temperatures.
Methods: The observing campaign involved simultaneous ground-based monitoring at ra…
Spectroscopy of clusters in the ESO distant cluster survey (EDisCS). II.. Redshifts, velocity dispersions, and substructure for clusters in the last 15 fields
Moustakas, J.; Pelló, R.; White, S. D. M. +17 more
Aims: We present spectroscopic observations of galaxies in 15 survey fields as part of the ESO Distant Cluster Survey (EDisCS). We determine the redshifts and velocity dispersions of the galaxy clusters located in these fields, and we test for possible substructure in the clusters.
Methods: We obtained multi-object mask spectroscopy using the …
Tracing a disk wind in NGC 3516
Turner, T. J.; Kraemer, S. B.; Reeves, J. N. +1 more
Context: X-ray spectra of AGN often contain signatures indicative of absorption in multiple layers of gas whose ionization-state and covering fraction may vary with time. It has been unclear to date how much of the observed X-ray spectral and timing behavior in AGN can be attributed to variations in absorption, versus variations in the strengths o…