Search Publications
The surprising magnetic topology of τ Sco: fossil remnant or dynamo output?
Bouret, J. -C.; Donati, J. -F.; Howarth, I. D. +9 more
We report the discovery of a medium-strength (~0.5 kG) magnetic field on the young, massive star τ Sco (B0.2V), which becomes the third-hottest magnetic star known. Circularly polarized Zeeman signatures are clearly detected in observations collected mostly with the ESPaDOnS spectropolarimeter, recently installed on the 3.6-m Canada-France-Hawaii …
On the reliability of CIVλ1549 as an abundance indicator for high-redshift star-forming galaxies
Pettini, Max; Steidel, Charles C.; Crowther, Paul A. +1 more
We reconsider the use of the equivalent width of CIVλ1549, EW(CIV), as an indicator of the oxygen abundance in star-forming galaxies, as proposed by Heckman et al. for nearby starbursts. We refine the local calibration of EW(CIV) versus log(O/H) by using a restricted wavelength window which minimizes blending with interstellar absorption lines. Wh…
A data-driven Bayesian approach for finding young stellar populations in early-type galaxies from their ultraviolet-optical spectra
Raychaudhury, Somak; Nolan, Louisa A.; Harva, Markus O. +1 more
Efficient predictive models and data analysis techniques for the analysis of photometric and spectroscopic observations of galaxies are not only desirable, but also required, in view of the overwhelming quantities of data becoming available. We present the results of a novel application of Bayesian latent variable modelling techniques, where we ha…
Ultraviolet variability of the magnetic chemically peculiar star 56 Arietis
Sokolov, N. A.
The spectrophotometric variability of the magnetic chemically peculiar star 56 Arietis (56 Ari) in the far-ultraviolet spectral region from 1150 to 1980 Å is investigated. This study is based on the archival International Ultraviolet Explorer data obtained at different phases of the rotational cycle. The brightness of 56 Ari is not constant in the…
Composite spectra Paper 14: HR 1129, a long-period binary showing evidence of circumbinary material
Stickland, D. J.; Griffin, R. E. M.; Griffin, R. F.
HR 1129 is a 4.8-mag star in the constellation Camelopardus, strangely (in view of its brightness) lacking a constellation designation. It has long been known to exhibit a composite spectrum consisting of a late-type primary and an early-type secondary. The radial velocity of the primary is easily measured, and was announced as variable nearly 100…