Search Publications
Six millisecond pulsars detected by the Fermi Large Area Telescope and the radio/gamma-ray connection of millisecond pulsars
Camilo, F.; Çelik, Ö.; Guillemot, L. +23 more
We report on the discovery of gamma-ray pulsations from five millisecond pulsars (MSPs) using the Fermi Large Area Telescope (LAT) and timing ephemerides provided by various radio observatories. We also present confirmation of the gamma-ray pulsations from a sixth source, PSR J2051-0827. Five of these six MSPs are in binary systems: PSRs J1713+074…
Optical polarimetry of the inner Crab nebula and pulsar
De Luca, A.; Mignani, R. P.; Laurent, P. +4 more
Time-resolved polarization measurements of pulsars offer a unique insight into the geometry of their emission regions. Such measurements provide observational constraints on the different models proposed for the pulsar emission mechanisms. Optical polarization data of the Crab nebula were obtained from the Hubble Space Telescope (HST) archive. The…
Inferring the mass of submillimetre galaxies by exploiting their gravitational magnification of background galaxies
Pérez-Fournon, I.; Valtchanov, I.; Ivison, R. J. +25 more
Dust emission at submillimetre wavelengths allows us to trace the early phases of star formation in the Universe. In order to understand the physical processes involved in this mode of star formation, it is essential to gain knowledge about the dark matter structures - most importantly their masses - that submillimetre galaxies live in. Here we us…
A tidal flare candidate in Abell 1795
Ho, L. C.; Maksym, W. P.; Ulmer, M. P. +2 more
As part of our ongoing archival X-ray survey of galaxy clusters for tidal flares, we present evidence of an X-ray transient source within 1 arcmin of the core of Abell 1795. The extreme variability (a factor of nearly 50), luminosity (>2 × 1042 erg s-1), long duration (>5 yr) and supersoft X-ray spectrum (<0.1 keV) a…
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…