Search Publications
Infrared spectroscopy of asymptotic giant branch stars in the Galactic bulge
Waters, L. B. F. M.; Blommaert, J. A. D. L.; Schultheis, M. +8 more
We have selected a homogeneous sample of asymptotic giant branch (AGB) stars in the Galactic bulge population from the ISOGAL survey. Our target stars cover a wide range of mass-loss rates (∼10-8-10-4 M⊙ yr-1) and differ primarily by their age on the AGB. This homogeneous sample is thus ideally suited to…
Constraints on the winds of hot subdwarf stars from X-ray observations of two sdB binaries with compact companions: CD -30° 11223 and PG 1232-136
Tiengo, A.; Mereghetti, S.; Geier, S. +5 more
Little observational data are available on the weak stellar winds of hot subdwarf stars of B spectral type (sdB). Close binary systems composed of an sdB star and a compact object (white dwarf, neutron star or black hole) could be detected as accretion-powered X-ray sources. The study of their X-ray emission can probe the properties of line-driven…
High spatial resolution of the mid-infrared emission of the Compton-thick type 2 Seyfert galaxy, Markarian 3
Pastoriza, M. G.; Winge, Cláudia; Sales, Dinalva A. +2 more
The mid-infrared (MIR) spectra observed with Gemini/Michelle have been used to study the nuclear region of the Compton-thick type 2 Seyfert galaxy, Markarian 3 (Mrk 3), at a spatial resolution of ∼200 pc. No polycyclic aromatic hydrocarbon emission bands were detected in the N-band spectrum of Mrk 3. However, intense [Ar III] 8.99 µm, [S IV]…
Application of the Baade-Wesselink method to a pulsating cluster Herbig Ae star: H254 in IC348
Ripepi, V.; Molinaro, R.; Palla, F. +6 more
In this paper we present new photometric and radial velocity data for the PMS δ Sct star H254, member of the young cluster IC 348. Photometric V, RC, IC light curves were obtained at the Loiano and Asiago telescopes. The radial velocity data were acquired by means of the SARG@Telescopio Nazionale Galileo spectrograph. High-re…
The effect of spatial resolution on optical and near-IR studies of stellar clusters: implications for the origin of the red excess
Schirmer, M.; Bastian, N.; Adamo, A. +6 more
Recent ground-based near-IR (NIR) studies of stellar clusters in nearby galaxies have suggested that young clusters remain embedded for 7-10 Myr in their progenitor molecular cloud, in conflict with optical-based studies which find that clusters are exposed after 1-3 Myr. Here, we investigate the role that spatial resolution plays in this apparent…
The puzzling X-ray continuum of the quasar MR 2251-178
Grosso, N.; Porquet, D.; Reeves, J. N. +3 more
We report on a comprehensive X-ray spectral analysis of the nearby radio-quiet quasar MR 2251-178, based on the long-look (∼400 ks) XMM-Newton observation carried out in 2011 November. As the properties of the multiphase warm absorber (thoroughly discussed in a recent, complementary work) hint at a steep photoionizing continuum, here we investigat…
Variations and correlations in cyclotron resonant scattering features of Vela X-1 studied by INTEGRAL
Wang, Wei
Long-term hard X-ray monitoring observations of high-mass X-ray binary Vela X-1 from 2003-2011 have been carried out by the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL). I systematically analysed the average hard X-ray spectra of Vela X-1 from 3-200 keV, with the main aims of detecting cyclotron resonant scattering features and study…
Absorption at the dust sublimation radius and the dichotomy between X-ray and optical classification in the Seyfert galaxy H0557-385
Bianchi, S.; Guainazzi, M.; Ballo, L. +7 more
In this work, the analysis of multi-epoch (1995-2010) X-ray observations of the Seyfert 1 galaxy H0557-385 is presented. The wealth of data presented in this analysis show that the source exhibits dramatic spectral variability, from a typical unabsorbed Seyfert 1 type spectrum to a Compton-thin absorbed state, on time-scales of ∼5 yr. This extreme…
High proper motion X-ray binaries from the Yale Southern Proper Motion Survey
Maccarone, Thomas J.; Casetti-Dinescu, Dana I.; Girard, Terrence M.
We discuss the results of cross-correlating catalogues of bright X-ray binaries with the Yale Southern Proper Motion Catalog (version 4.0). Several objects already known to have large proper motions from Hipparcos are recovered. Two additional objects are found which show substantial proper motions, both of which are unusual in their X-ray propert…
The structure of Abell 1351: a bimodal galaxy cluster with peculiar diffuse radio emission
Rossetti, M.; De Grandi, S.; Boschin, W. +2 more
We aim to review the internal structure and dynamics of the Abell 1351 cluster, shown to host a radio halo with a quite irregular shape. Our analysis is based on radial velocity data for 135 galaxies obtained at the Telescopio Nazionale Galileo. We combine galaxy velocities and positions to select 95 cluster galaxy members and analyse the internal…