Search Publications
Weak- and strong-lensing analyses of the triaxial matter distribution of Abell 1689
Umetsu, Keiichi; Sereno, Mauro
Haloes formed in the standard Λ cold dark matter framework should follow a universal mass density profile and fit a well-defined mass-concentration relation. Lensing analyses of clusters with a large Einstein radius seem to contradict this scenario, with the massive cluster Abell 1689 being often claimed as a notable example of a highly over-conce…
Modelling galaxy and AGN evolution in the infrared: black hole accretion versus star formation activity
Pozzi, F.; Vignali, C.; Gruppioni, C. +1 more
We present a new backward evolution model for galaxies and active galactic nuclei (AGNs) in the infrared (IR). What is new in this model is the separate study of the evolutionary properties of different IR populations (i.e. spiral galaxies, starburst galaxies, low-luminosity AGNs, 'unobscured' type 1 AGNs and 'obscured' type 2 AGNs) defined throug…
Simulated spectral states of active galactic nuclei and observational predictions
Gierliński, Marek; Siemiginowska, Aneta; Sobolewska, Małgorzata A.
Active galactic nuclei (AGN) and galactic black hole binaries (GBHs) represent two classes of accreting black holes. They both contain an accretion disc emitting a thermal radiation, and a non-thermal X-ray emitting 'corona'. GBHs exhibit state transitions, and the spectral states are characterized by different luminosity levels and shapes of the …
The star formation history of the Large Magellanic Cloud star cluster NGC 1751
Goudfrooij, Paul; Kozhurina-Platais, Vera; Rubele, Stefano +2 more
The HST/ACS colour-magnitude diagrams (CMDs) of the populous Large Magellanic Cloud (LMC) star cluster NGC 1751 present both a broad main-sequence turn-off and a dual clump of red giants. We show that the latter feature is real and associate it to the first appearance of electron degeneracy in the H-exhausted cores of the cluster stars. We then ap…
Herschel-ATLAS: statistical properties of Galactic cirrus in the GAMA-9 Hour Science Demonstration Phase Field
Rodighiero, G.; Ivison, R. J.; Clements, D. L. +35 more
We study the spectral energy distribution (SED) and the power spectrum of Galactic cirrus emission observed in the 14 deg2 Science Demonstration Phase field of the Herschel-ATLAS using Herschel and IRAS data from 100 to 500 µm. We compare the Spectral and Photometric Imaging Receiver (SPIRE) 250, 350 and 500 µm maps with IRA…
Spatially resolved kinematics of an ultracompact dwarf galaxy
Infante, L.; Grebel, E. K.; Hilker, M. +3 more
We present the internal kinematics of UCD3, the brightest known ultracompact dwarf galaxy (UCD) in the Fornax cluster, making this the first UCD with spatially resolved spectroscopy. Our study is based on seeing-limited observations obtained with the ARGUS Integral Field Unit of the VLT/FLAMES spectrograph under excellent seeing conditions (0.5-0.…
An analytic model for blue straggler formation in globular clusters
Sills, Alison; Knigge, Christian; Leigh, Nathan
We present an analytic model for blue straggler formation in globular clusters. We assume that blue stragglers are formed only through stellar collisions and binary star evolution, and compare our predictions to observed blue straggler numbers. We can summarize our key results as follows. (1) Binary star evolution consistently dominates blue strag…
PTF10ops - a subluminous, normal-width light curve Type Ia supernova in the middle of nowhere
Cenko, S. B.; Bloom, J. S.; Gal-Yam, A. +26 more
PTF10ops is a Type Ia supernova (SN Ia), whose light curve and spectral properties place it outside the current SN Ia subtype classifications. Its spectra display the characteristic lines of subluminous SNe Ia, but it has a normal-width light curve with a long rise time, typical of normal-luminosity SNe Ia. The early-time optical spectra of PTF10o…
Radio to infrared spectra of late-type galaxies with Planck and Wilkinson Microwave Anisotropy Probe data
Clements, D. L.; Davies, R. D.; Dickinson, C. +2 more
We use the Planck Early Release Compact Source Catalogue combined with Wilkinson Microwave Anisotropy Probe (WMAP) and other archival measurements to construct continuum spectra of three nearby dusty star-forming galaxies: Messier 82, NGC 253 and NGC 4945. We carry out a least-squares fit to the spectra using a combination of simple synchrotron, f…
Herschel observations of the Centaurus cluster - the dynamics of cold gas in a cool core
Böhringer, H.; Fabian, A. C.; Combes, F. +15 more
Brightest cluster galaxies (BCGs) in the cores of galaxy clusters have distinctly different properties from other low-redshift massive ellipticals. The majority of the BCGs in cool-core clusters show signs of active star formation. We present observations of NGC 4696, the BCG of the Centaurus galaxy cluster, at far-infrared (FIR) wavelengths with …