Search Publications
The polarized gamma-ray burst GRB 061122
Covino, S.; Götz, D.; Bošnjak, Ž. +2 more
We report on the polarization measure, obtained with IBIS on board INTEGRAL, of the prompt emission of GRB 061122. Over an 8 s interval containing the brightest part of the gamma-ray burst (GRB) we put a lower limit on its polarization fraction of 60 per cent at 68 per cent confidence level (c.l.) and of 33 per cent at 90 per cent c.l. on the 250-…
Population of persistent high-mass X-ray binaries in the Milky Way
Tsygankov, S. S.; Lutovinov, A. A.; Revnivtsev, M. G. +1 more
We present results of the study of persistent high-mass X-ray binaries (HMXBs) in the Milky Way, obtained from the deep INTEGRAL Galactic plane survey. This survey provides us a new insight into the population of HMXBs because almost half of the whole sample consists of sources discovered with INTEGRAL. It is demonstrated for the first time that t…
A low-mass cut-off near the hydrogen burning limit for Salpeter-like initial mass functions in early-type galaxies
Treu, Tommaso; Czoske, Oliver; Koopmans, Léon V. E. +3 more
We conduct a detailed investigation of the properties of the stellar initial mass function (IMF) in two massive early-type lens galaxies with velocity dispersions of σ ≃ 245 and 325 km s-1, for which both Hubble Space Telescope imaging and X-Shooter spectra are available. We compare the inferences obtained from two fully independent met…
Molecular gas in the centre of nearby galaxies from VLT/SINFONI integral field spectroscopy - I. Morphology and mass inventory
Saglia, R. P.; Nowak, N.; Thomas, J. +7 more
We present the first results of an analysis of the properties of the molecular gas in the nuclear regions (r ≲ 300 pc) of a sample of six nearby galaxies, based on new high-spatial-resolution observations obtained in the K-band with the near-infrared integral field spectrograph SINFONI at the Very Large Telescope. We derive 2D distributions of the…
Galaxy Zoo: bulgeless galaxies with growing black holes
Moran, Edward C.; Schawinski, Kevin; Kaviraj, Sugata +8 more
The growth of supermassive black holes appears to be driven by galaxy mergers, violent merger-free processes and/or `secular' processes. In order to quantify the effects of secular evolution on black hole growth, we study a sample of active galactic nuclei (AGN) in galaxies with a calm formation history free of significant mergers, a population th…
X-ray exploration of the outskirts of the nearby Centaurus cluster using Suzaku and Chandra
Simionescu, A.; Fabian, A. C.; Sanders, J. S. +2 more
We present Suzaku observations of the Centaurus cluster out to 0.95r200, taken along a strip to the north-west. We have also used congruent Chandra observations of the outskirts to resolve point sources down to a threshold flux around seven times lower than that achievable with just Suzaku data, considerably reducing the systematic unce…
Discovery of a magnetic field in the rapidly rotating O-type secondary of the colliding-wind binary HD 47129 (Plaskett's star)
Martins, F.; Wade, G. A.; Neiner, C. +14 more
We report the detection of a strong, organized magnetic field in the secondary component of the massive O8III/I+O7.5V/III double-lined spectroscopic binary system HD 47129 (Plaskett's star) in the context of the Magnetism in Massive Stars survey. Eight independent Stokes V observations were acquired using the Echelle SpectroPolarimetric Device for…
Velocity width measurements of the coolest X-ray emitting material in the cores of clusters, groups and elliptical galaxies
Fabian, A. C.; Sanders, J. S.
We examine the velocity width of cool X-ray emitting material using XMM-Newton Reflection Grating Spectrometer (RGS) spectra of a sample of clusters and group of galaxies and elliptical galaxies. Improving on our previous analyses, we apply a spectral model which accounts for broadening due to the spatial extent of the source. With both convention…
An improved model for the infrared emission from the zodiacal dust cloud: cometary, asteroidal and interstellar dust
Rowan-Robinson, M.; May, B.
We model the infrared emission from zodiacal dust detected by the IRAS and COBE missions, with the aim of estimating the relative contributions of asteroidal, cometary and interstellar dust to the zodiacal cloud. Our most important result is the detection of an isotropic component of foreground radiation due to the interstellar dust.
The dust…On the two high-metallicity DLAs at z = 2.412 and 2.583 towards Q 0918+1636
Vestergaard, M.; Fynbo, J. P. U.; Krühler, T. +9 more
The quasar Q0918+1636 (z = 3.07) has two intervening high-metallicity Damped Lyman α Absorbers (DLAs) along the line of sight, at redshifts of z = 2.412 and 2.583. The z = 2.583 DLA is located at a large impact parameter of 16.2 kpc, and despite this large impact parameter it has a very high metallicity (consistent with solar), a substantial fract…