Search Publications
Suzaku and SWIFT-BAT observations of a newly discovered Compton-thick AGN
Moretti, A.; Vignali, C.; La Parola, V. +4 more
Context. Obscured AGN are fundamental to understand the history of supermassive black hole growth and their influence on galaxy formation. However, the Compton-thick AGN (NH > 1024 cm-2) population is basically unconstrained, with less than a few dozen confirmed Compton-thick AGN found and studied so far. A way …
The initial conditions of high-mass star formation: radiative transfer models of IRDCs seen in the Herschel Hi-GAL survey
Griffin, M.; Peretto, N.; Ward-Thompson, D. +13 more
The densest infrared dark clouds (IRDCs) may represent the earliest observable stage of high-mass star formation. These clouds are very cold, hence they emit mainly at far-infrared and sub-mm wavelengths. For the first time, Herschel has provided multi-wavelength, spatially resolved observations of cores within IRDCs, which, when combined with rad…
Evidence for a resonant cyclotron line in IGR J16493-4348 from the Swift-BAT hard X-ray survey
Cusumano, G.; Robba, N. R.; La Parola, V. +4 more
Context. Resonant absorption cyclotron features are a key diagnostic tool to directly measure the strength of the magnetic field of accreting neutron stars. However, typical values of cyclotron features lie in the high-energy part of the spectrum between 20 keV and 50 keV, where detection is often damped by the low quality statistics of results de…
Evolution of the fundamental plane of 0.2 < z < 1.2 early-type galaxies in the EGS
Cepa, J.; Bongiovanni, A.; Pérez García, A. M. +5 more
Context. The fundamental plane links the structural properties of early-type galaxies such as its surface brightness and effective radius with its dynamics. The study of the fundamental plane evolution therefore has important implications for models of galaxy formation and evolution.
Aims: This work aims to identify signs of evolution of earl…
Optical and infrared properties of active galactic nuclei in the Lockman Hole
Burwitz, V.; Salvato, M.; Rovilos, E. +4 more
We present the observed-frame optical, near-, and mid-infrared properties of X-ray-selected active galactic nuclei (AGN) in the Lockman Hole. Using a likelihood ratio method on optical, near-infrared or mid-infrared catalogues, we assigned counterparts to 401 out of the 409 X-ray sources of the XMM-Newton catalogue. Accurate photometry was collect…
Modelling solar irradiance variability on time scales from minutes to months
Solanki, S. K.; Krivova, N. A.; Seleznyov, A. D.
We analyze and model total solar irradiance variability on time scales from minutes to months, excluding variations due to p-mode oscillations, using a combination of convective and magnetic components. These include granulation, the magnetic network, faculae and sunspots. Analysis of VIRGO data shows that on periods of a day or longer solar varia…
Intercomparison of SCIAMACHY and SIM vis-IR irradiance over several solar rotational timescales
Weber, M.; Pagaran, J.; Harder, J. W. +2 more
The two satellite spectrometers SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) aboard ENVISAT (Environmental Satellite), and SIM (Spectral Irradiance Monitor) aboard SORCE (Solar Radiation and Climate Experiment) observe since 2002 and 2003, respectively, daily solar spectral irradiance (SSI) not only in UV but e…
IGR J11014-6103: a newly discovered pulsar wind nebula?
Walter, R.; Ferrigno, C.; Bozzo, E. +3 more
Context. IGR J11014-6103 is one of the still unidentified hard X-ray INTEGRAL sources, reported for the first time in the 4th IBIS/ISGRI catalog.
Aims: We investigated the nature of IGR J11014-6103 by carrying out a multiwavelength analysis of the available archival observations performed in the direction of the source.
Methods: We prese…
Detecting emission lines with XMM-Newton in 4U 1538-52
Torrejón, J. M.; Osborne, J. P.; Page, K. L. +2 more
Context. The properties of the X-ray emission lines are a fundamental tool for studying the nature of the matter surrounding the neutron star and the phenomena that produce these lines.
Aims: The aim of this work is to analyse the X-ray spectrum of 4U 1538-52 obtained by the XMM-Newton observatory and to look for the presence of diagnostic li…
VLT optical BVR observations of two bright supernova Ia hosts in the Virgo cluster. Surface brightness fluctuation analysis
Cantiello, M.; Brocato, E.; Raimondo, G. +1 more
Aims: We study the characteristics of field stars in the two bright ellipticals NGC 4621 and NGC 4374 in the Virgo cluster to derive accurate distances and stellar population properties. Moreover, since the target galaxies have hosted three type Ia supernova events, we investigate the possible correlations between the SNe Ia properties and th…