Search Publications
On the effects of clouds and hazes in the atmospheres of hot Jupiters: semi-analytical temperature-pressure profiles
Sing, David K.; Heng, Kevin; Pont, Frédéric +1 more
Motivated by the work of Guillot, we present a semi-analytical formalism for calculating the temperature-pressure profiles in hot Jovian atmospheres which includes the effects of clouds/hazes and collision-induced absorption. Using the dual-band approximation, we assume that stellar irradiation and thermal emission from the hot Jupiter occur at di…
Integral field spectroscopy of 2.0< z<2.7 submillimetre galaxies: gas morphologies and kinematics
Smail, Ian; Alexander, D. M.; Umehata, H. +8 more
We present 2D, integral field spectroscopy covering the rest-frame wavelengths of strong optical emission lines in nine submillimetre luminous galaxies (SMGs) at 2.0 < z < 2.7. The Gemini-North/Near-Infrared Integral Field Spectrograph (NIFS) and Very Large Telescope (VLT) Spectrograph for INtegral Field Observations in the Near Infrared (SI…
On the influence of the companion star in Eta Carinae: 2D radiative transfer modelling of the ultraviolet and optical spectra
Hillier, D. John; Weigelt, Gerd; Madura, Thomas I. +1 more
We present two-dimensional (2D) radiative transfer modelling of the Eta Carinae binary system accounting for the presence of a wind-wind collision (WWC) cavity carved in the optically thick wind of the primary star. By comparing synthetic line profiles with spectra obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph near …
A combined optical and X-ray study of unobscured type 1 active galactic nuclei - II. Relation between X-ray emission and optical spectra
Done, Chris; Ward, Martin; Jin, Chichuan
In this second paper in a series of three, we study the properties of the various emission features and underlying continuum in the optical spectra of type 1 active galactic nuclei (AGNs) by using the unobscured hard X-ray emission as a diagnostic. We introduce the use of the 'correlation spectrum technique' (CST) for the first time. We use this t…
A study of X-ray flares - II. RS CVn-type binaries
Pandey, J. C.; Singh, K. P.
We present an analysis of seven flares detected from five RS CVn-type binaries (UZ Lib, σ Gem, λ And, V711 Tau and EI Eri) observed with XMM-Newton observatory. The quiescent state X-ray luminosities in the energy band of 0.3-10.0 keV of these stars were found to be 1030.7-30.9 erg s-1. The exponential decay time in all the s…
Gas sloshing, cold fronts, Kelvin-Helmholtz instabilities and the merger history of the cluster of galaxies Abell 496
Ghizzardi, S.; Lovisari, L.; Brüggen, M. +4 more
We investigate the origin and nature of the multiple sloshing cold fronts in the core of Abell 496 by direct comparison between observations and dedicated hydrodynamical simulations. Our simulations model a minor merger with a 4 × 1013 M⊙ subcluster crossing A496 from the south-west to the north-north-east, passing the cluste…
HR 5907: Discovery of the most rapidly rotating magnetic early B-type star by the MiMeS Collaboration
Rivinius, Th.; Wade, G. A.; Bohlender, D. A. +14 more
We report the discovery and analysis of a very strong magnetic field in the rapidly rotating early B-type star HR 5907, based on observations obtained as part of the Magnetism in Massive Stars (MiMeS) project. We infer a rotation period of 0.508 276+0.000 015-0.000 012 d from photometric and Hα EW measurements, making this th…
On the masses of OJ287 black holes
Ciprini, S.; Lehto, H. J.; Valtonen, M. J.
Two multifrequency campaigns were carried out on OJ287 in 2005: in April when it was in its pre-outburst state, and in November during the main 12 yr cycle outburst. The wavelength coverage was from radio to X-rays. In the optical-to-ultraviolet range, the differential spectrum between the observations has a bremsstrahlung spectral shape, consiste…
Optical flux and spectral variability of blazars
Gupta, Alok C.; Wiita, Paul J.; Bachev, R. +9 more
We report the results of optical monitoring for a sample of 11 blazars including 10 BL Lacertae objects (BL Lacs) and one flat spectrum radio quasar (FSRQ). We have measured the multiband optical flux and colour variations in these blazars on intraday and short-term time-scales of months and have limited data for two more blazars. These photometri…
A Sunyaev-Zel'dovich take on cluster radio haloes - I. Global scaling and bi-modality using Planck data
Basu, Kaustuv
Giant radio haloes in galaxy clusters are the primary evidence for the existence of relativistic particles (cosmic rays) and magnetic fields over Mpc scales. Observational tests for the different theoretical models explaining their powering mechanism have so far been obtained through X-ray selection of clusters, e.g. by comparing cluster X-ray lum…