Search Publications
The mosaic multiple stellar populations in ω Centauri: the horizontal branch and the main sequence
Di Criscienzo, M.; D'Antona, F.; Tailo, M. +2 more
We interpret the stellar population of ω Centauri by means of a population synthesis analysis, following the most recent observational guidelines for input metallicities, helium and [(C+N+O)/Fe] contents. We deal at the same time with the main sequences, sub-giant and horizontal branch (HB) data. The reproduction of the observed colour-magnitude f…
Deep Chandra observation and numerical studies of the nearest cluster cold front in the sky
Simionescu, A.; Fabian, A. C.; Markevitch, M. +9 more
We present the results of a very deep (500 ks) Chandra observation, along with tailored numerical simulations, of the nearest, best resolved cluster cold front in the sky, which lies 90 kpc (19 arcmin) to the north-west of M 87. The northern part of the front appears the sharpest, with a width smaller than 2.5 kpc (1.5 Coulomb mean free paths; at …
Herschel protocluster survey: a search for dusty star-forming galaxies in protoclusters at z = 2-3
Lehmer, B. D.; Smail, Ian; Alexander, D. M. +15 more
We present a Herschel/Spectral and Photometric Imaging Receiver (SPIRE) survey of three protoclusters at z = 2-3 (2QZCluster, HS1700, SSA22). Based on the SPIRE colours (S350/S250 and S500/S350) of 250 µm sources, we selected high-redshift dusty star-forming galaxies potentially associated with the…
The Hubble Space Telescope UV Legacy Survey of Galactic globular clusters - X. The radial distribution of stellar populations in NGC 2808
Milone, A. P.; Bedin, L. R.; Piotto, G. +4 more
Due to their extreme helium abundance, the multiple stellar populations of the globular cluster NGC 2808 have been widely investigated from a photometric, spectroscopic, and kinematic perspective. The most striking feature of the colour-magnitude diagram of NGC 2808 is the triple main sequence (MS), with the red MS corresponding to a stellar popul…
Extreme star formation events in quasar hosts over 0.5 < z < 4
Wang, L.; Feltre, A.; Hatziminaoglou, E. +7 more
We explore the relationship between active galactic nuclei (AGN) and star formation in a sample of 513 optically luminous type 1 quasars up to redshifts of ∼4 hosting extremely high star formation rates (SFRs). The quasars are selected to be individually detected by the Herschel SPIRE instrument at >3σ at 250 µm, leading to typical SFRs o…
Towards the statistical detection of the warm-hot intergalactic medium in intercluster filaments of the cosmic web
Prochaska, J. Xavier; Tejos, Nicolas; Morris, Simon L. +6 more
Modern analyses of structure formation predict a universe tangled in a `cosmic web' of dark matter and diffuse baryons. These theories further predict that at low z, a significant fraction of the baryons will be shock-heated to T ∼ 105-107 K yielding a warm-hot intergalactic medium (WHIM), but whose actual existence has elude…
H2S in the L1157-B1 bow shock
Viti, Serena; Bachiller, Rafael; Ceccarelli, Cecilia +8 more
Sulphur-bearing molecules are highly reactive in the gas phase of the interstellar medium. However, the form in which most of the sulphur is locked on to interstellar dust grains is unknown. By taking advantage of the short time-scales of shocks in young molecular outflows, one could track back the main form of sulphur in the ices. In this paper, …
Abundance stratification in Type Ia supernovae - V. SN 1986G bridging the gap between normal and subluminous SNe Ia
Pian, E.; Ashall, C.; Mazzali, P. A. +1 more
A detailed spectroscopic analysis of SN 1986G has been performed. SN 1986G `bridges the gap' between normal and subluminous Type Ia supernovae (SNe Ia). The abundance tomography technique is used to determine the abundance distribution of the elements in the ejecta. SN 1986G was found to be a low-energy Chandrasekhar mass explosion. Its kinetic en…
Explaining the reportedly overmassive black holes in early-type galaxies with intermediate-scale discs
Graham, Alister W.; Savorgnan, Giulia A. D.
The classification `early-type' galaxy includes both elliptically and lenticular-shaped galaxies. Theoretically, the spheroid-to-disc flux ratio of an early-type galaxy can assume any positive value, but in practice studies often consider only spheroid/disc decompositions in which the disc neatly dominates over the spheroid at large galaxy radii, …
The formation of bulges, discs and two-component galaxies in the CANDELS Survey at z < 3
Conselice, Christopher J.; Mortlock, Alice; Dekel, Avishai +5 more
We examine a sample of 1495 galaxies in the CANDELS fields to determine the evolution of two-component galaxies, including bulges and discs, within massive galaxies at the epoch 1 < z < 3 when the Hubble sequence forms. We fit all of our galaxies' light profiles with a single Sérsic fit, as well as with a combination of exponential and Sérsi…