Search Publications
The soft X-ray/NLR connection: a single photoionized medium?
Bianchi, S.; Guainazzi, M.; Chiaberge, M.
We present a sample of 8 nearby Seyfert 2 galaxies observed by HST and Chandra. All of the sources present soft X-ray emission which is coincident in extension and overall morphology with the [O iii] emission. The spectral analysis reveals that the soft X-ray emission of all the objects is likely to be dominated by a photoionized gas. This is stro…
X-ray spectral survey with XMM-Newton of a complete sample of nearby Seyfert galaxies
Cappi, M.; Filippenko, A. V.; Piconcelli, E. +15 more
Results obtained from an X-ray spectral survey of nearby Seyfert galaxies using XMM-Newton are reported. The sample was optically selected, well defined, complete in B magnitude, and distance limited: it consists of the nearest (D ⪉22 Mpc) 27 Seyfert galaxies (9 of type 1, 18 of type 2) taken from the Ho et al. (1997a, ApJS, 112, 315) sample. This…
2MASS wide field extinction maps. I. The Pipe nebula
Alves, J.; Lombardi, M.; Lada, C. J.
Context: .
Aims: . We present a 8°×6°, high resolution extinction map of the Pipe nebula using 4.5 million stars from the Two Micron All Sky Survey (2MASS) point source catalog.
Methods: . The use of Nicer (Lombardi & Alves 2001, A&A, 377, 1023), a robust and optimal technique to map the dust column density, allows us to detect a…
Keplerian discs around post-AGB stars: a common phenomenon?
Waters, L. B. F. M.; Dejonghe, H.; de Ruyter, S. +3 more
Aims.We aim at showing that the broad-band SED characteristics of our sample of post-AGB stars are best interpreted, assuming the circumstellar dust is stored in Keplerian rotating passive discs.Methods.We present a homogeneous and systematic study of the Spectral Energy Distributions (SEDs) of a sample of 51 post-AGB objects. The selection criter…
Evolutionary state of magnetic chemically peculiar stars
Kochukhov, O.; Bagnulo, S.
Context: .The photospheres of about 5-10% of the upper main sequence stars exhibit remarkable chemical anomalies. Many of these chemically peculiar (CP) stars have a global magnetic field, the origin of which is still a matter of debate.
Aims: .We present a comprehensive statistical investigation of the evolution of magnetic CP stars, aimed at…
Spectral analysis of the Galactic e+e- annihilation emission
Knödlseder, J.; Marcowith, A.; Guessoum, N. +5 more
We present a spectral analysis of the e+e- annihilation emission from the Galactic Centre region based on the first year of measurements made with the spectrometer SPI of the INTEGRAL mission. We have found that the annihilation spectrum can be modelled by the sum of a narrow and a broad 511 keV line plus an ortho-positronium…
Effective temperature scale and bolometric corrections from 2MASS photometry
Ribas, I.; Jordi, C.; Masana, E.
We present a method to determine effective temperatures, angular semi-diameters and bolometric corrections for population I and II FGK type stars based on V and 2MASS IR photometry. Accurate calibration is accomplished by using a sample of solar analogues, whose average temperature is assumed to be equal to the solar effective temperature of 5777 …
The great observatories origins deep survey. VLT/FORS2 spectroscopy in the GOODS-South Field: Part II
Popesso, P.; Cesarsky, C.; Stern, D. +16 more
Aims.We present the second campaign of the ESO/GOODS program of spectroscopy of faint galaxies in the GOODS-South field.
Methods: .Objects were selected as candidates for VLT/FORS2 observations primarily based on the expectation that the detection and measurement of their spectral features would benefit from the high throughput and spectral re…
Origin of the Galactic ridge X-ray emission
Sunyaev, R.; Revnivtsev, M.; Sazonov, S. +2 more
We analyze a map of the Galactic ridge X-ray emission (GRXE) constructed in the 3-20 keV energy band from RXTE/PCA scan and slew observations. We show that the GRXE intensity follows the Galactic near-infrared surface brightness closely and thus traces the Galactic stellar mass distribution. The GRXE consists of two spatial components that can be …
The unprecedented optical outburst of the quasar 3C 454.3 . The WEBT campaign of 2004-2005
Lee, C. -U.; Lähteenmäki, A.; Umana, G. +85 more
Context: .The radio quasar
Aims: .In order to follow the emission behaviour of the …