Search Publications
Warm-hot gas in X-ray bright galaxy clusters and the H I-deficient circumgalactic medium in dense environments
Bowen, David V.; Tripp, Todd M.; Jenkins, Edward B. +3 more
We analyse the intracluster medium (ICM) and circumgalactic medium (CGM) in seven X-ray-detected galaxy clusters using spectra of background quasi-stellar objects (QSOs) (HST-COS/STIS), optical spectroscopy of the cluster galaxies (MMT/Hectospec and SDSS), and X-ray imaging/spectroscopy (XMM-Newton and Chandra). First, we report a very low coverin…
The low-luminosity accretion disc wind of the black hole transient V4641 Sagittarii
Garcia, Michael R.; Torres, Manuel A. P.; Muñoz-Darias, Teo
We present an optical spectroscopic study of the black hole X-ray transient V4641 Sgr (=SAX J1819.3-2525) covering the 1999, 2002, and 2004 outbursts. The spectra were taken over 22 different epochs during the low-luminosity phases that follow the sharp and bright outburst peaks displayed by the system. The data reveal the frequent presence of win…
The very young resolved stellar populations around stripped-envelope supernovae
Maund, Justyn R.
The massive star origins for Type IIP supernovae (SNe) have been established through direct detection of their red supergiants progenitors in pre-explosion observations; however, there has been limited success in the detection of the progenitors of H-deficient SNe. The final fate of more massive stars, capable of undergoing a Wolf-Rayet phase, and…
Predicting the hypervelocity star population in Gaia
Rossi, E. M.; Brown, A. G. A.; Marchetti, T. +3 more
Hypervelocity stars (HVSs) are amongst the fastest objects in our Milky Way. These stars are predicted to come from the Galactic centre (GC) and travel along unbound orbits across the Galaxy. In the coming years, the ESA satellite Gaia will provide the most complete and accurate catalogue of the Milky Way, with full astrometric parameters for more…
Growing a 'cosmic beast': observations and simulations of MACS J0717.5+3745
Kneib, J. -P.; Eckert, D.; Jullo, E. +18 more
We present a gravitational lensing and X-ray analysis of a massive galaxy cluster and its surroundings. The core of MACS J0717.5+3745 ($M(R\lt 1\, {\rm Mpc})\sim$ $2 \times 10^{15}\, \, {\rm M}_{\odot }$, $z$ = 0.54) is already known to contain four merging components. We show that this is surrounded by at least seven additional substructures with…
Testing modified-gravity theories via wide binaries and GAIA
Sutherland, Will; Pittordis, Charalambos
The standard Lambda cold dark matter model based on general relativity (GR) including cold dark matter (DM) is very successful at fitting cosmological observations, but recent non-detections of candidate dark matter particles mean that various modified-gravity theories remain of significant interest. The latter generally involve modifications to G…
A new catalogue of Galactic novae: investigation of the MMRD relation and spatial distribution
Güver, Tolga; Özdönmez, Aykut; Ege, Ergün +1 more
In this study, a new Galactic novae catalogue is introduced collecting important parameters of these sources such as their light-curve parameters, classifications, full width half-maximum (FWHM) of Hα line, distances and interstellar reddening estimates. The catalogue is also published on a website with a search option via a SQL query and an onlin…
Fast winds drive slow shells: a model for the circumgalactic medium as galactic wind-driven bubbles
Thompson, Todd A.; Weinberg, David H.; Quataert, Eliot +1 more
Successful models of the low-redshift circumgalactic medium (CGM) must account for (1) a large amount of gas, (2) relatively slow gas velocities, (3) a high degree of metal enrichment, (4) the similar absorption properties around both star-forming and passive galaxies, and (5) the observationally inferred temperature and densities of the CGM gas. …
On the kinematics of a runaway Be star population
Evans, N. W.; Boubert, D.
We explore the hypothesis that B-type emission-line stars (Be stars) have their origin in mass-transfer binaries by measuring the fraction of runaway Be stars. We assemble the largest-to-date catalogue of 632 Be stars with 6D kinematics, exploiting the precise astrometry of the Tycho-Gaia Astrometric Solution from the first Gaia data release. Usin…
A direct calibration of thtae IRX-β relation in Lyman-break Galaxies at z = 3-5
Scott, D.; McLure, R. J.; Dunlop, J. S. +17 more
We use a sample of 4209 Lyman-break galaxies (LBGs) at z ≃ 3, 4, and 5 in the UKIRT Infrared Deep Sky Survey Ultra Deep Survey field to investigate the relationship between the observed slope of the stellar continuum emission in the ultraviolet, β, and the thermal dust emission, as quantified via the so-called 'infrared excess' (IRX ≡ LIR/LUV). Th…