Search Publications
The HELLAS2XMM Survey. I. The X-Ray Data and the logN-logS Relation
Fiore, F.; Vignali, C.; Molendi, S. +3 more
We present the first results from an XMM-Newton serendipitous medium-deep survey, which covers nearly 3 deg2. We detect a total of 1022, 495, and 100 sources, down to minimum fluxes of about 5.9×10-16, 2.8×10-15, and 6.2×10-15 ergs cm-2 s-1, in the 0.5-2, 2-10, and 4.5-10 keV bands,…
The Star Formation History and Spatial Distribution of Stellar Populations in the Ursa Minor Dwarf Spheroidal Galaxy
Aparicio, Antonio; Martínez-Delgado, David; Alonso-García, Javier +1 more
As a part of a project devoted to the study of the Ursa Minor dwarf spheroidal (dSph) galaxy, the star formation history of the galaxy is presented. The analysis uses wide-field photometry, encompassing about 1°×1° (the total covered area being 0.75 deg2), which samples the galaxy out to its tidal radius. Derivation of the star formatio…
ISO spectroscopy of compact H II regions in the Galaxy. I. The catalogue
Kessler, M. F.; Morisset, C.; Schaerer, D. +9 more
Infrared spectra between 2.3 and 196 µm were taken towards a sample of 45 compact H II regions using the two spectrometers (SWS and LWS) on board ISO. The primary goal is to determine the distribution of element abundances in the Galaxy, although there are also many other uses of this database. The spectra contain a wealth of information on …
The physical properties of the Lyα forest at z > 1.5
Cristiani, S.; Giallongo, E.; Carswell, R. F. +2 more
Combining a new, increased data set of eight quasi-stellar objects (QSOs) covering the Lyα forest at redshifts 1.5 > z < 3.6 from VLT/UVES observations with previously published results, we have investigated the properties of the Lyα forest at 1.5 < z <4. With the six QSOs covering the Lyα forest at 1.5 < z < 2.5, we have extende…
Discovery of an Ionized Fe K Edge in the z=3.91 Broad Absorption Line Quasar APM 08279+5255 with XMM-Newton
Schartel, N.; Hasinger, G.; Komossa, S.
Recent XMM-Newton observations of the high-redshift, lensed, broad absorption line (BAL) quasi-stellar object APM 08279+5255, one of the most luminous objects in the universe, allowed the detection of a high column density absorber (NH~1023 cm-2) in the form of a K-shell absorption edge of significantly ionized iro…
Control of Jupiter's radio emission and aurorae by the solar wind
Gurnett, D. A.; Persoon, A. M.; Dougherty, M. K. +14 more
Radio emissions from Jupiter provided the first evidence that this giant planet has a strong magnetic field and a large magnetosphere. Jupiter also has polar aurorae, which are similar in many respects to Earth's aurorae. The radio emissions are believed to be generated along the high-latitude magnetic field lines by the same electrons that produc…
An ISO-SWS survey of molecular hydrogen in starburst and Seyfert galaxies
Lutz, D.; Genzel, R.; Rigopoulou, D. +2 more
We present results from a survey of molecular hydrogen emission from a sample of Starburst and Seyfert galaxies carried out with the Infrared Space Observatory (ISO). Pure rotational H2 emission has been detected in a number of extragalactic objects and a variety of environments. A number of transitions from S(7) to S(0) are detected in…
Variability of Southern T Tauri Stars. II. The Spectral Variability of the Classical T Tauri Star TW Hydrae
Alencar, Silvia H. P.; Batalha, Celso
We present the analysis of 42 spectra of the Classical T Tauri star TW Hya observed with the FEROS echelle spectrograph over 2 yr. We determined the rotational and radial velocities of TW Hya, obtaining vsini=5+/-2 km s-1 and vrad=12.5+/-0.5 km s-1. The star exhibits strong emission lines that show substantial vari…
Far Ultraviolet Spectroscopic Explorer and Space Telescope Imaging Spectrograph Observations of Intervening O VI Absorption Line Systems in the Spectrum of PG 0953+415
Savage, B. D.; Sembach, K. R.; Richter, P. +1 more
We present Far Ultraviolet Spectroscopic Explorer (FUSE) and Space Telescope Imaging Spectrograph (STIS) observations of the intergalactic medium toward the bright QSO PG 0953+415 (zem=0.239). The FUSE spectra extend from 905 to 1187 Å and have a resolution of 25 km s-1, while the STIS spectra cover 1150-1730 Å and have a res…
Chandra observations of the luminous infrared galaxy NGC 3256
Zezas, A.; Ward, M.; Lira, P. +2 more
We present a detailed analysis of high-resolution Chandra observations of the merger system NGC 3256, the most infrared-luminous galaxy in the nearby universe. The X-ray data show that several discrete sources embedded in complex diffuse emission contribute >~20 per cent of the total emission (LtotX\sim 8\times 1041\,erg\,s…