Search Publications
Basic parameters and properties of the rapidly rotating magnetic helium-strong B star HR 7355
Štefl, S.; Baade, D.; Kochukhov, O. +4 more
The spectral and magnetic properties and variability of the B2Vnp emission-line magnetosphere star HR 7355 were analysed. The object rotates at almost 90 per cent of the critical value, meaning it is a magnetic star for which oblateness and gravity darkening effects cannot be ignored any longer. A detailed modelling of the photospheric parameters …
The ages, masses and star formation rates of spectroscopically confirmed z ∼ 6 galaxies in CANDELS
Dickinson, M.; Ferguson, H. C.; Finkelstein, S. L. +22 more
We report the results of a study exploring the stellar populations of 13 luminous (L > 1.2L*), spectroscopically confirmed, galaxies in the redshift interval 5.5 < z < 6.5, all with Hubble Space Telescope (HST) Wide Field Camera 3/infrared and Spitzer Infrared Array Camera imaging from the HST/Cosmic Assembly Near-infrared Deep Survey and…
Growth of brightest cluster galaxies via mergers since z=1
Collins, Chris A.; Burke, Claire
Hierarchical assembly within clusters of galaxies is tied directly to the evolution of the brightest cluster galaxies (BCGs), which dominate the stellar light in the centres of rich clusters. In this paper, we investigate the number of mergers on to BCGs in 14 X-ray-selected clusters over the redshift range 0.8 < z < 1.4 using HST imaging da…
A high Eddington-ratio, true Seyfert 2 galaxy candidate: implications for broad-line region models
Read, A. M.; Esquej, P.; Rodríguez-Pascual, P. M. +5 more
A bright, soft X-ray source was detected on 2010 July 14 during an XMM-Newton slew at a position consistent with the galaxy GSN 069 (z = 0.018). Previous ROSAT observations failed to detect the source and imply that GSN 069 is now ≥240 times brighter than it was in 1994 in the soft X-ray band. Optical spectra (from 2001 to 2003) are dominated by u…
Intranight optical variability of γ-ray-loud narrow-line Seyfert 1 galaxies
Stalin, C. S.; Yadav, R. K. S.; Pandey, S. B. +4 more
The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope has detected γ-ray emission in about half a dozen narrow-line Seyfert 1 (NLSy1) galaxies. This indicates the presence of relativistic jets in these sources similar to blazars and radio galaxies. In an attempt to have an idea of the intranight optical variability (INOV) cha…
Radio observations of extreme ULXs: revealing the most powerful ULX radio nebula ever or the jet of an intermediate-mass black hole?
Roberts, T. P.; Mezcua, M.; Sutton, A. D. +1 more
The most extreme ultraluminous X-ray sources (ULXs), with LX > 5 × 1040 erg s-1, are amongst the best candidates for hosting intermediate-mass black holes (IMBHs) in the haloes of galaxies. Jet radio emission is expected from a sub-Eddington accreting IMBH in the low/hard (radio bright) state. In a search for su…
Is the black hole in NGC 1277 really overmassive?
Emsellem, Eric
A recent claim has been made by van den Bosch et al. that the fast-rotator galaxy NGC 1277 hosts an overmassive black hole with a mass (1.7 × 1010 M⊙) larger than half its (central) stellar spheroid mass. We revisit this claim here by examining the predictions from simple dynamical realizations based on new multi-Gaussian exp…
First X-ray evidence for a shock at the Coma relic
Brüggen, M.; Ogrean, G. A.
The Coma cluster is one of the nearest galaxy clusters, and the first one in which a peripheral radio relic was discovered. However, X-ray observations of the plasma near the relic have been scarce. Here, we present results from a re-analysis of a 22 ks archival XMM-Newton observation. Across the relic, we detect a temperature discontinuity indica…
Herschel reveals the obscured star formation in HiZELS Hα emitters at z = 1.47
Smail, I.; Berta, S.; Magnelli, B. +28 more
We describe the far-infrared (far-IR; rest-frame 8-1000-µm) properties of a sample of 443 Hα-selected star-forming galaxies in the Cosmic Evolution Survey (COSMOS) and Ultra Deep Survey (UDS) fields detected by the High-redshift Emission Line Survey (HiZELS) imaging survey. Sources are identified using narrow-band filters in combination with…
H-ATLAS: estimating redshifts of Herschel sources from sub-mm fluxes
Valtchanov, I.; Ivison, R. J.; Scott, D. +29 more
Upon its completion, the Herschel Astrophysics Terahertz Large Area Survey (H-ATLAS) will be the largest sub-millimetre survey to date, detecting close to half-a-million sources. It will only be possible to measure spectroscopic redshifts for a small fraction of these sources. However, if the rest-frame spectral energy distribution (SED) of a typi…