Search Publications
SWIFT view of the 2015 outburst of GS 2023+338 (V404 Cyg): complex evolution of spectral and temporal characteristics
Nandi, A.; Mandal, S.; Agrawal, V. K. +1 more
We study the spectral and temporal characteristics of the source GS 2023+338 (V404 Cyg) during the initial phase of its 2015 June outburst, over the energy range of 0.5-150 keV. This is the first detailed study of the characteristics of this source based on SWIFT observations, being reported. Based on our analysis, we understand that the source ex…
Studying the evolution of AGB stars in the Gaia epoch
Di Criscienzo, M.; Dell'Agli, F.; Ventura, P. +6 more
We present asymptotic giant branch (AGB) models of solar metallicity, to allow the interpretation of observations of Galactic AGB stars, whose distances should be soon available after the first release of the Gaia catalogue. We find an abrupt change in the AGB physical and chemical properties, occurring at the threshold mass to ignite hot bottom b…
Giant scattering cones in obscured quasars
Zakamska, Nadia L.; Wylezalek, Dominika; Obied, Georges +1 more
We analyse Hubble Space Telescope observations of scattering regions in 20 luminous obscured quasars at 0.24 < z < 0.65 (11 new observations and nine archival ones) observed at rest frame ∼3000 Å. We find spectacular 5-10 kpc-scale scattering regions in almost all cases. The median scattering efficiency at this wavelength (the ratio of obser…
Updated measurements of the dark matter halo masses of obscured quasars with improved WISE and Planck data
Hickox, R. C.; DiPompeo, M. A.; Myers, A. D.
Using the most recent releases of WISE and Planck data, we perform updated measurements of the bias and typical dark matter halo mass of infrared (IR)-selected obscured and unobscured quasars, using the angular autocorrelation function and cosmic microwave background lensing cross-correlations. Since our recent work of this kind, the WISE ALLWISE …
Local SDSS galaxies in the Herschel Stripe 82 survey: a critical assessment of optically derived star formation rates
Lutz, D.; Trump, J. R.; Mendel, J. T. +2 more
We study a set of 3319 galaxies in the redshift interval 0.04 < z < 0.15 with far-infrared (FIR) coverage from the Herschel Stripe 82 survey (HerS), and emission-line measurements, redshifts, stellar masses and star formation rates (SFRs) from the Sloan Digital Sky Survey (SDSS) (DR7) MPA/JHU data base. About 40 per cent of the sample are de…
Soft γ-ray selected radio galaxies: favouring giant size discovery
Venturi, T.; Dallacasa, D.; Ubertini, P. +5 more
Using the recent INTEGRAL/IBIS and Swift/BAT surveys we have extracted a sample of 64 confirmed plus three candidate radio galaxies selected in the soft gamma-ray band. The sample covers all optical classes and is dominated by objects showing a Fanaroff-Riley type II radio morphology; a large fraction (70 per cent) of the sample is made of `radiat…
A variable ULX and possible IMBH candidate in M51a
Done, Chris; Middleton, Matthew J.; Sutton, Andrew D. +7 more
Ultraluminous X-ray source (ULX)-7, in the northern spiral arm of M51, demonstrates unusual behaviour for an ULX, with a hard X-ray spectrum but very high short-term variability. This suggests that it is not in a typical ultraluminous state. We analyse the source using archival data from XMM-Newton, Chandra and NuSTAR, and by examining optical and…
The binary populations of eight globular clusters in the outer halo of the Milky Way
Milone, A. P.; Marino, A. F.; Bedin, L. R. +6 more
We analyse colour-magnitude diagrams of eight globular clusters (GCs) in the outer Galactic halo. Images were taken with the Wide Field Channel of the Advanced Camera for Survey and the Ultraviolet and Visual Channel of the Wide Field Camera 3 on board of the Hubble Space Telescope. We have determined the fraction of binary stars along the main se…
Acceleration of cometary dust near the nucleus: application to 67P/Churyumov-Gerasimenko
Hartogh, Paul; Skorov, Yuri; Reshetnyk, Volodymyr +2 more
We present a model of cometary dust capable of simulating the dynamics within the first few tens of km of the comet surface. Recent measurements by the Grain Impact Analyser and Dust Accumulator and Cometary Secondary Ion Mass Analyser instruments on Rosetta show that the nucleus emits fluffy dust particles with porosities above 50 per cent and si…
The multiplicity of 250-µm Herschel sources in the COSMOS field
Griffin, Matt; Oliver, Seb; Wang, Lingyu +5 more
We investigate the multiplicity of extragalactic sources detected by the Herschel Space Observatory in the COSMOS field. Using 3.6- and 24-µm catalogues, in conjunction with 250-µm data from Herschel, we seek to determine if a significant fraction of Herschel sources are composed of multiple components emitting at 250 µm. We use …