Search Publications
The template type Ia supernova 1996X
Turatto, M.; Cappellaro, E.; Benetti, S. +4 more
UBVRIJ photometry and optical spectra of the type Ia SN 1996X obtained at the European Southern Observatory (ESO) during a 1-yr-long observational campaign are presented, and supplemented by late-time Hubble Space Telescope (HST) photometry. Spectroscopically, SN 1996X appears to be a `normal' SN Ia. The apparent magnitude at maximum was B=13.24+/…
Stellar populations and surface brightness fluctuations: new observations and models
Vazdekis, Alexandre; Ajhar, Edward A.; Blakeslee, John P.
We investigate the use of surface brightness fluctuations (SBF) measurements in optical and near-IR bandpasses for both stellar population and distance studies. New V-band SBF data are reported for five galaxies in the Fornax cluster and combined with literature data to define a V-band SBF distance indicator, calibrated against Cepheid distances t…
The star cluster system of the 3-Gyr-old merger remnant NGC 1316: clues from optical and near-infrared photometry
Minniti, Dante; Maraston, Claudia; Goudfrooij, Paul +1 more
The giant merger remnant galaxy NGC 1316 (Fornax A) is an ideal probe for studying the long-term effects of a past major merger on star cluster systems, given its spectroscopically derived merger age of ~3Gyr which we reported in a recent paper. Here we present new ground-based, large-area optical and near-IR imaging of star clusters in NGC 1316. …
Multiwavelength analyses of the extraordinary nova LMC 1991*
Della Valle, M.; Baron, E.; Shore, S. N. +3 more
LMC 91 was a very fast, classical nova and the brightest nova ever observed in the Large Magellanic Cloud. It was extensively observed during both its early optically thick and its nebular evolution in the optical and UV wavelength regions. We successfully fit all the optically thick spectra using a grid of spherically symmetric, non-LTE, line-bla…
The cluster environments of powerful radio-loud and radio-quiet active galactic nuclei
McLure, R. J.; Dunlop, J. S.
The spatial clustering amplitude (Bgq) is determined for a sample of 44 powerful active galactic nuclei (AGN) at z~=0.2. No significant difference is detected in the richness of the cluster environments of the radio-loud and radio-quiet subsamples, both of which typically inhabit environments as rich as Abell class ~=0. Comparison with …
Timing the millisecond pulsars in 47 Tucanae
Camilo, F.; Lorimer, D. R.; Freire, P. C. +3 more
In the last ten years, 20 millisecond pulsars have been discovered in the globular cluster 47 Tucanae. Hitherto, only three of these pulsars had published timing solutions. Here we improve upon these three and present 12 new solutions. These measurements can be used to determine a variety of physical properties of the pulsars and of the cluster. T…
Numerical simulations of weak lensing measurements
Refregier, Alexandre; Ellis, Richard S.; Clowe, Douglas +1 more
Weak gravitational lensing induces distortions on the images of background galaxies, and thus provides a direct measure of mass fluctuations in the Universe. The distortion signature from large-scale structure has recently been detected by several groups for the first time, opening promising prospects for the near future. Since the distortions ind…
NICMOS imaging search for high-redshift damped Lyα galaxies
Jakobsen, P.; Fall, S. M.; Møller, P. +1 more
We are engaged in a programme of imaging with the STIS and NICMOS (NIC2) instruments aboard the Hubble Space Telescope (HST), to search for the galaxy counterparts of 18 high-redshift z>1.75 damped Lyα absorption lines and five Lyman-limit systems seen in the spectra of 16 target quasars. This paper presents the results of the imaging campaign …
Circumstellar structure of RU Lupi down to au scales
Gledhill, T. M.; Hough, J. H.; Chrysostomou, A. +2 more
We have used the technique of spectro-astrometry to study the milliarcsecond scale structure of the emission lines in the T Tauri star RU Lupi. The wings of the Hα emission are found to be displaced from the star towards the south-west (blue wing) and north-east (red wing) with angular scales of 20-30mas. This structure is consistent with a bipola…
Surveying the sky with the Arcminute MicroKelvin Imager: expected constraints on galaxy cluster evolution and cosmology
Lasenby, Anthony N.; Cotter, Garret; Grainge, Keith +4 more
We discuss prospects for cluster detection via the Sunyaev-Zel'dovich (SZ) effect in a blank field survey with the interferometer array, the Arcminute MicroKelvin Imager (AMI). Clusters of galaxies selected in the SZ effect probe cosmology and structure formation with little observational bias, because the effect measures integrated gas pressure d…