Search Publications
The column density distribution of hard X-ray radio galaxies
Venturi, T.; Dallacasa, D.; Ubertini, P. +6 more
In order to investigate the role of absorption in active galactic nuclei (AGN) with jets, we have studied the column density distribution of a hard X-ray selected sample of radio galaxies, derived from the INTEGRAL/Imager on Board the Integral Satellite (IBIS) and Swift/The Burst Alert Telescope (BAT) AGN catalogues (∼7-10 per cent of the total AG…
Accurate parameters for HD 209458 and its planet from HST spectrophotometry
del Burgo, C.; Allende Prieto, C.
We present updated parameters for the star HD 209458 and its transiting giant planet. The stellar angular diameter θ = 0.2254 ± 0.0017 mas is obtained from the average ratio between the absolute flux observed with the Hubble Space Telescope and that of the best-fitting Kurucz model atmosphere. This angular diameter represents an improvement in pre…
Spectral and timing evolution of the bright failed outburst of the transient black hole Swift J174510.8-262411
Sbarufatti, B.; Homan, J.; Tomsick, J. A. +13 more
We studied time variability and spectral evolution of the Galactic black hole transient Swift J174510.8-262411 during the first phase of its outburst. INTEGRAL and Swift observations collected from 2012 September 16 until October 30 have been used. The total squared fractional rms values did not drop below 5 per cent and quasi-periodic oscillation…
The X-ray dust-scattered rings of the black hole low-mass binary V404 Cyg
Vasilopoulos, G.; Petropoulou, M.
We report on the first detection of X-ray dust-scattered rings from the Galactic low-mass X-ray binary V404 Cyg. The observation of the system with Swift/XRT on 2015 June 30 revealed the presence of five concentric ring-like structures centred at the position of V404 Cyg. Follow-up Swift/XRT observations allowed a time-dependent study of the X-ray…
Geomorphological mapping of comet 67P/Churyumov-Gerasimenko's Southern hemisphere
Bertaux, Jean-Loup; Da Deppo, Vania; Naletto, Giampiero +49 more
In 2015 May, the Southern hemisphere of comet 67P/Churyumov-Gerasimenko became visible by the OSIRIS cameras on-board the Rosetta spacecraft. The resolution was high enough to carry out a detailed analysis of the surface morphology, which is quite different from the Northern hemisphere. Previous works show that fine particle deposits are the most …
The perihelion activity of comet 67P/Churyumov-Gerasimenko as seen by robotic telescopes
Meech, Karen J.; Snodgrass, Colin; Lister, Tim +13 more
Around the time of its perihelion passage, the observability of 67P/Churyumov-Gerasimenko from Earth was limited to very short windows each morning from any given site, due to the low solar elongation of the comet. The peak in the comet's activity was therefore difficult to observe with conventionally scheduled telescopes, but was possible where s…
Properties of the cluster population of NGC 1566 and their implications
Bastian, N.; Ryon, J. E.; Adamo, A. +2 more
We present results of a photometric study into the cluster population of NGC 1566, a nearby grand design spiral galaxy, sampled out to a Galactocentric radius of ≈5.5 kpc. The shape of the mass-limited age distribution shows negligible variation with radial distance from the centre of the galaxy, and demonstrates three separate sections, with a st…
Searching in the dark: the dark mass content of the Milky Way globular clusters NGC288 and NGC6218
Dalessandro, E.; Mucciarelli, A.; Origlia, L. +8 more
We present an observational estimate of the fraction and distribution of dark mass in the innermost region of the two Galactic globular clusters NGC 6218 (M12) and NGC 288. Such an assessment has been made by comparing the dynamical and luminous mass profiles derived from an accurate analysis of the most extensive spectroscopic and photometric sur…
Distance and extinction determination for APOGEE stars with Bayesian method
Shi, Jianrong; Pan, Kaike; Chen, Bingqiu +3 more
Using a Bayesian technology, we derived distances and extinctions for over 100 000 red giant stars observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey by taking into account spectroscopic constraints from the APOGEE stellar parameters and photometric constraints from Two Micron All-Sky Survey, as well as a prior …
Rings and arcs around evolved stars - I. Fingerprints of the last gasps in the formation process of planetary nebulae
Guerrero, M. A.; Toalá, J. A.; Santamaría, E. +3 more
Evolved stars such as asymptotic giant branch stars (AGB), post-AGB stars, proto-planetary nebulae (proto-PNe), and planetary nebulae (PNe) show rings and arcs around them and their nebular shells. We have searched for these morphological features in optical Hubble Space Telescope and mid-infrared Spitzer Space Telescope images of ∼650 proto-PNe a…