Search Publications
In search of massive single-population globular clusters
D'Antona, Francesca; Caloi, Vittoria
The vast majority of globular clusters so far examined shows the chemical signatures of hosting (at least) two stellar populations. According to recent ideas, this feature requires a two-step process, in which the nuclearly processed matter from a 'first generation' (FG) of stars gives birth to a 'second generation' (SG), bearing the fingerprint o…
The evolution of stellar structures in dwarf galaxies
Walter, F.; Bastian, N.; Kennicutt, R. C. +8 more
We present a study of the variation of spatial structure of stellar populations within dwarf galaxies as a function of the population age. We use deep Hubble Space Telescope/Advanced Camera for Surveys imaging of nearby dwarf galaxies in order to resolve individual stars and create composite colour-magnitude diagrams (CMDs) for each galaxy. Using …
Ice chemistry in massive young stellar objects: the role of metallicity
van Loon, J. Th.; Indebetouw, R.; Tielens, A. G. G. M. +6 more
We present the comparison of the three most important ice constituents (water, CO and CO2) in the envelopes of massive young stellar objects (YSOs), in environments of different metallicities: the Galaxy, the Large Magellanic Cloud (LMC) and, for the first time, the Small Magellanic Cloud (SMC). We present observations of water, CO and …
Relationship between eruptions of active-region filaments and associated flares and coronal mass ejections
Yan, X. -L.; Qu, Z. -Q.; Kong, D. -F.
To better understand the dynamical process of active-region filament eruptions and associated flares and coronal mass ejections (CMEs), we carried out a statistical study of 120 events observed by Big Bear Solar Observatory (BBSO), Transition Region and Coronal Explorer (TRACE) and the Extreme-ultraviolet Imaging Telescope (EIT) on board Solar and…
Infrared luminosity functions of AKARI Sloan Digital Sky Survey galaxies
Goto, Tomotsugu; Inami, Hanae; Nakagawa, Takao +16 more
By cross-correlating the AKARI all-sky survey in six infrared (IR) bands (9, 18, 65, 90, 140 and 160 µm) with the Sloan Digital Sky Survey (SDSS) galaxies, we identified 2357 IR galaxies with a spectroscopic redshift. This is not just one of the largest samples of local IR galaxies, but AKARI provides crucial far-IR (FIR) bands for accuratel…
Suzaku observation of the transient X-ray pulsar GRO J1008-57
Paul, Biswajit; Naik, Sachindra; Vadawale, Santosh V. +1 more
We report the timing and broad-band spectral properties of the Be transient high-mass X-ray binary pulsar GRO J1008-57 using a Suzaku observation in the declining phase of its 2007 November and December outbursts. Pulsations with a period of 93.737 s were clearly detected in the light curves of the pulsar up to the 80-100 keV energy band. The puls…
The effects of X-ray absorption variability in NGC 4395
Nardini, E.; Risaliti, G.
We present a new X-ray analysis of the dwarf Seyfert galaxy NGC 4395, based on two archival XMM-Newton and Suzaku observations. This source is well known for a series of remarkable properties: one of the smallest estimated black hole masses among active galactic nuclei (AGN) (of the order of ∼105 M⊙), intense flux variability…
Strong-lensing analysis of MS 1358.4+6245: New multiple images and implications for the well-resolved z= 4.92 galaxy
Broadhurst, Tom; Zitrin, Adi; Coe, Dan +5 more
We present a strong-lensing analysis of the galaxy cluster MS 1358.4+6245 (z= 0.33), in deep six-band HST/ACS imaging. In addition to the well-studied system at z= 4.92, our modelling method uncovers 19 new multiply lensed images belonging to seven background sources, so that a total of 23 images and their redshifts are used to accurately constrai…
The scatter in the radial profiles of X-ray luminous galaxy clusters as diagnostic of the thermodynamical state of the ICM
Ettori, S.; Roncarelli, M.; Vazza, F. +1 more
We study the azimuthal scatter in the radial profiles of X-ray luminous galaxy clusters with two sets of high-resolution cosmological re-simulations obtained with the codes ENZO and GADGET2. The average gas profiles are computed for different angular sectors of the cluster projected volume and compared with the mean cluster profiles at each radius…
Revealing O VII from stacked X-ray grating spectra of clusters, groups and elliptical galaxies
Fabian, A. C.; Sanders, J. S.
We stack 4.6 Ms of high spectral resolution XMM-Newton Reflection Grating Spectrometer spectra from galaxy clusters, groups of galaxies and elliptical galaxies. For those objects with a central temperature of less than 1 keV, we detect O VII for the first time, with a probability of false detection of 2.5 × 10-4. The flux ratio of the O…