Search Publications
Probing isotopic ratios at z = 0.89: molecular line absorption in front of the quasar PKS 1830-211
Combes, F.; Muller, S.; Guélin, M. +2 more
With the Plateau de Bure interferometer, we have measured the C, N, O and S isotopic abundance ratios in the arm of a spiral galaxy with a redshift of 0.89. The galaxy is seen face-on according to HST images. Its bulge intercepts the line of sight to the radio-loud quasar
The host galaxy/AGN connection in nearby early-type galaxies. A new view of the origin of the radio-quiet/radio-loud dichotomy?
Capetti, A.; Balmaverde, B.
This is the third in a series of three papers exploring the connection between the multiwavelength properties of AGN in nearby early-type galaxies and the characteristics of their hosts. Starting from an initial sample of 332 galaxies, we selected 116 AGN candidates requiring the detection of a radio source with a flux limit of ~1 mJy, as measured…
The UV spectrum of HS 1700+6416. II. FUSE observations of the He II Lyman alpha forest
Shull, J. M.; Zheng, W.; Moos, H. W. +11 more
Aims.We present the far-UV spectrum of the quasar
INTEGRAL observation of the high-mass X-ray transient V 0332+53 during the 2005 outburst decline
Rodriguez, J.; Mowlavi, N.; Wilms, J. +7 more
The decline of the high mass X-ray transient V 0332+53 during the Dec. 2004 to Feb. 2005 outburst is analysed from the data recorded by INTEGRAL. The flux is shown to decrease exponentially until 2005 Feb. 10, with a decay time scale of ~30 days above 20 keV and ~20 days at lower energies, and to decrease linearly thereafter. The energy spectrum i…
Testing the inverse-Compton catastrophe scenario in the intra-day variable blazar S5 0716+71 . I. Simultaneous broadband observations during November 2003
Lähteenmäki, A.; Smith, N.; Chen, W. P. +72 more
Context.Some intra-day variable, compact extra-galactic radio sources show brightness temperatures severely exceeding 1012 K, the limit set by catastrophic inverse-Compton (IC) cooling in sources of incoherent synchrotron radiation. The violation of the IC limit, actually possible under non-stationary conditions, would lead to IC avalan…
The XMM-Newton survey of the ELAIS-S1 field. I. Number counts, angular correlation function and X-ray spectral properties
Berta, S.; D'Elia, V.; Fiore, F. +16 more
Aims.The formation and evolution of cosmic structures can be probed by studying the evolution of the luminosity function of the Active Galactic Nuclei (AGNs), galaxies and clusters of galaxies and of the clustering of the X-ray active Universe, compared to the IR-UV active Universe.
Methods: .To this purpose, we have surveyed with XMM-Newton t…
The supermassive black hole in Centaurus A: a benchmark for gas kinematical measurements
Marconi, A.; Capetti, A.; Koekemoer, A. M. +5 more
We present new HST Space Telescope Imaging Spectrograph observations of the nearby radio galaxy NGC 5128 (Centaurus A). The bright emission line with longest wavelength accessible from HST, [S III]λ 9533 Å, was used to study the kinematics of the ionized gas in the nuclear region with a 0.1 arcsec spatial resolution. The STIS data were analized in…
Multifrequency variability of the blazar AO 0235+164 . The WEBT campaign in 2004-2005 and long-term SED analysis
Lee, C. -U.; Ilyin, I.; Lähteenmäki, A. +58 more
Aims.A huge multiwavelength campaign targeting the blazar
Methods: .Monitoring observations were carried out at cm and mm wavelengths, and in the near-IR and optical bands, while three pointing…
Planetary nebulae abundances and stellar evolution
Pottasch, S. R.; Bernard-Salas, J.
A summary is given of planetary nebulae abundances from ISO measurements. It is shown that these nebulae show abundance gradients (with galactocentric distance), which in the case of neon, argon, sulfur and oxygen (with four exceptions) are the same as HII regions and early type star abundance gradients. The abundance of these elements predicted f…
Non-thermal cosmic backgrounds from blazars: the contribution to the CMB, X-ray and γ-ray backgrounds
Cavazzuti, E.; Colafrancesco, S.; Giommi, P. +2 more
We present a new assessment of the contribution of the blazar population to the extragalactic background radiation across the electromagnetic spectrum. Our calculations rely on deep blazar radio counts that we have derived by combining several radio and multi-frequency surveys. We show that blazar emission integrated over cosmic time gives rise to…