Search Publications
Accretion disc-corona and jet emission from the radio-loud narrow-line Seyfert 1 galaxy RX J1633.3+4719
Misra, R.; Dewangan, G. C.; Gandhi, P. +2 more
We perform X-ray/ultraviolet (UV) spectral and X-ray variability studies of the radio-loud narrow-line Seyfert 1 (NLS1) galaxy RX J1633.3+4719 using XMM-Newton and Suzaku observations from 2011 and 2012. The 0.3-10 keV spectra consist of an ultrasoft component described by an accretion disc blackbody (kT_in = 39.6^{+11.2}_{-5.5} eV) and a power la…
The XMM Cluster Survey: evolution of the velocity dispersion-temperature relation over half a Hubble time
Hilton, Matt; Stott, John P.; Thomas, Peter A. +26 more
We measure the evolution of the velocity dispersion-temperature (σv-TX) relation up to z = 1 using a sample of 38 galaxy clusters drawn from the XMM Cluster Survey. This work improves upon previous studies by the use of a homogeneous cluster sample and in terms of the number of high-redshift clusters included. We present here…
The spatially resolved dynamics of dusty starburst galaxies in a z ∼ 0.4 cluster: beginning the transition from spirals to S0s
Smail, Ian; Swinbank, A. M.; Bower, R. G. +4 more
To investigate what drives the reversal of the morphology-density relation at intermediate/high redshift, we present a multiwavelength analysis of 27 dusty starburst galaxies in the massive cluster Cl 0024+17 at z = 0.4. We combine Hα dynamical maps from the VLT/FLAMES multi-IFU system with far-infrared imaging using Herschel/SPIRE and millimetre …
Gaia transient detection efficiency: hunting for nuclear transients
Harrison, D. L.; Walton, N. A.; Wyrzykowski, Ł. +5 more
We present a study of the detectability of transient events associated with galaxies for the Gaia European Space Agency astrometric mission. We simulated the on-board detections, and on-ground processing for a mock galaxy catalogue to establish the properties required for the discovery of transient events by Gaia, specifically tidal disruption eve…
Reconstruction of small-scale galaxy cluster substructure with lensing flexion
Bradač, Maruša; Cain, Benjamin; Levinson, Rebecca
We present reconstructions of galaxy-cluster-scale mass distributions from simulated gravitational lensing data sets including strong lensing, weak lensing shear, and measurements of quadratic image distortions - flexion. The lensing data is constructed to make a direct comparison between mass reconstructions with and without flexion. We show that…
Improved orbits and parallaxes for eight visual binaries with unrealistic previous masses using the Hipparcos parallax
Docobo, J. A.; Malkov, O. Yu.; Tamazian, V. S. +2 more
Improved orbits are presented for the visual binaries WDS 02366+1227, WDS 02434-6643, WDS 03244-1539, WDS 08507+1800, WDS 09128-6055, WDS 11532-1540, WDS 17375+2419, and WDS 22408-0333. The latest orbits for these binaries were demonstrating a great inconsistency between the systemic mass obtained through Kepler's Third Law and that calculated as …
A far-ultraviolet variable with an 18-minute period in the globular cluster NGC 1851
Maccarone, T. J.; Knigge, C.; Sarajedini, A. +5 more
We present the detection of a variable star with an 18.05 min period in far-ultraviolet (FUV) images of the globular cluster NGC 1851 taken with the Hubble Space Telescope (HST). A candidate optical counterpart lies on the red horizontal branch or the asymptotic giant branch star of the cluster, but it is statistically possible that this is a chan…
Dependence of the broad Fe Kα line on the physical parameters of AGN
Lu, Youjun; Liu, Zhu; Yuan, Weimin +3 more
In this paper, the dependence of the broad Fe Kα line on the physical parameters of AGN, such as the black hole mass MBH, accretion rate (equivalently represented by Eddington ratio λEdd) and optical classification is investigated by applying the X-ray spectra stacking method to a large sample of AGN which have well measured …
Tidal bridge and tidal dwarf candidates in the interacting system Arp194
Egorov, Oleg V.; Zasov, Anatoly V.; Saburova, Anna S. +1 more
Arp194 is a system of recently collided galaxies, where the southern galaxy (S) passed through the gaseous disc of the northern galaxy (N) which in turn consists of two close components. This system is of special interest due to the presence of regions of active star formation in the bridge between galaxies, the brightest of which (the region A) h…
The young nuclear stellar disc in the SB0 galaxy NGC 1023
Morelli, L.; Dalla Bontà, E.; Corsini, E. M. +3 more
Small kinematically decoupled stellar discs with scalelengths of a few tens of parsec are known to reside in the centre of galaxies. Different mechanisms have been proposed to explain how they form, including gas dissipation and merging of globular clusters. Using archival Hubble Space Telescope imaging and ground-based integral-field spectroscopy…