Search Publications
Deep galaxy counts, extragalactic background light and the stellar baryon budget
Madau, Piero; Pozzetti, Lucia
We assess the constraints imposed by the observed extragalactic background light (EBL) on the cosmic history of star formation and the stellar-mass density today. The logarithmic slope of the galaxy number-magnitude relation from the Southern Hubble Deep Field imaging survey is flatter than 0.4 in all seven UBVIJHK optical bandpasses, i.e. the lig…
NGC 6153: a super-metal-rich planetary nebula?
Barlow, M. J.; Cohen, M.; Liu, X. -W. +3 more
We have obtained deep optical spectra of the planetary nebula NGC 6153, both along its minor axis and by uniformly scanning a long slit across the whole nebula. The scanned spectra, when combined with the nebular total Hβ flux, yield integrated fluxes for all the lines (~400) in our spectra, which are rich in strong recombination lines from C, N, …
Hubble Space Telescope imaging of the CFRS and LDSS redshift surveys - IV. Influence of mergers in the evolution of faint field galaxies from z~1
Glazebrook, K.; Le Fèvre, O.; Brinchmann, J. +9 more
Hubble Space Telescope images of a sample of 285 galaxies with measured redshifts from the Canada-France Redshift Survey (CFRS) and Autofib-Low Dispersion Spectrograph Survey (LDSS) redshift surveys are analysed to derive the evolution of the merger fraction out to redshifts z~1. We have performed visual and machine-based merger identifications, a…
The local density of matter mapped by Hipparcos
Flynn, Chris; Holmberg, Johan
We determine the velocity distribution and space density of a volume-complete sample of A and F stars, using parallaxes and proper motions from the Hipparcos satellite. We use these data to solve for the gravitational potential vertically in the local Galactic disc, by comparing the Hipparcos measured space density with predictions from various di…
The European Large Area ISO Survey - I. Goals, definition and observations
Elbaz, D.; Genzel, R.; Omont, A. +67 more
We describe the European Large Area ISO Survey (ELAIS). ELAIS was the largest single Open Time project conducted by ISO, mapping an area of 12deg2 at 15µm with ISOCAM and at 90µm with ISOPHOT. Secondary surveys in other ISO bands were undertaken by the ELAIS team within the fields of the primary survey, with 6deg2…
Infrared colours for Mira-like long-period variables found in the (M⊙<~10-7 Msolar yr-1) Hipparcos Catalogue
Feast, Michael; Whitelock, Patricia; Marang, Freddy
Near-infrared, JHKL, photometry is presented for 193 Mira and semi-regular variables that were observed by Hipparcos; periods, bolometric magnitudes and amplitudes are derived for 92 of them. Because of the way in which the Hipparcos targets were selected, this group of stars provides a useful data base of Miras with low mass-loss rates (M⊙
The age of the solar neighbourhood
Binney, James; Dehnen, Walter; Bertelli, Gianpaolo
High-quality Hipparcos data for a complete sample of nearly 12000 main-sequence and subgiant stars, together with Padua isochrones, are used to constrain the star formation history of the solar neigbourhood and the processes that stochastically accelerate disc stars. The velocity dispersion of a coeval group of stars is found to increase with time…
Non-parametric star formation histories for four dwarf spheroidal galaxies of the Local Group
Gilmore, Gerard; Valls-Gabaud, David; Hernandez, X.
We use recent Hubble Space Telescope colour-magnitude diagrams of the resolved stellar populations of a sample of local dSph galaxies (Carina, Leo I, Leo II and Ursa Minor) to infer the star formation histories of these systems, SFR(t). Applying a new variational calculus maximum likelihood method, which includes a full Bayesian analysis and allow…
Testing the connection between the X-ray and submillimetre source populations using Chandra
Kneib, J. -P.; Ivison, R. J.; Smail, Ian +8 more
The powerful combination of the Chandra X-ray telescope, the SCUBA submillimetre-wave camera and the gravitational lensing effect of the massive galaxy clusters A2390 and A1835 has been used to place stringent X-ray flux limits on six faint submillimetre SCUBA sources and deep submillimetre limits on three Chandra sources which lie in fields commo…
Quantitative analysis of WC stars: constraints on neon abundances from ISO-SWS spectroscopy
Hillier, D. John; Morris, Patrick W.; Crowther, Paul A. +3 more
Neon abundances are derived in four Galactic WC stars - γ2Vel (WR11, WC8+O7.5III), HD156385 (WR90, WC7), HD192103 (WR135, WC8) and WR146 (WC5+O8) - using mid-infrared fine-structure lines obtained with ISO-SWS. Stellar parameters for each star are derived using the non-local thermodynamic equilibrium model atmospheric code of Hillier &a…