Search Publications
H-ATLAS/GAMA: quantifying the morphological evolution of the galaxy population using cosmic calorimetry
Baes, Maarten; Smith, M. W. L.; Graham, Alister W. +28 more
Using results from the Herschel Astrophysical Terrahertz Large-Area Survey (H-ATLAS) and the Galaxy and Mass Assembly (GAMA) project, we show that, for galaxy masses above ≃ 108 M⊙, 51 per cent of the stellar mass-density in the local Universe is in early-type galaxies (ETGs; Sérsic n > 2.5) while 89 per cent of the rate o…
Probing large-scale wind structures in Vela X-1 using off-states with INTEGRAL
Sidoli, L.; Bozzo, E.; Pottschmidt, K. +4 more
Vela X-1 is the prototype of the class of wind-fed accreting pulsars in high-mass X-ray binaries hosting a supergiant donor. We have analysed in a systematic way 10 years of INTEGRAL data of Vela X-1 (22-50 keV) and we found that when outside the X-ray eclipse, the source undergoes several luminosity drops where the hard X-rays luminosity goes bel…
The companion candidate near Fomalhaut - a background neutron star?
Neuhäuser, R.; Schmidt, T. O. B.; Ginski, C. +3 more
The directly detected planetary mass companion candidate close to the young, nearby star Fomalhaut is a subject of intense discussion. While the detection of common proper motion led to the interpretation as Jovian-mass companion, later non-detections in the infrared raised doubts. Recent astrometric measurements indicate a belt crossing or highly…
Discovery of a new bona fide luminous blue variable in Norma
Berdnikov, L. N.; Gvaramadze, V. V.; Kniazev, A. Y.
We report the results of optical spectroscopy of the candidate evolved massive star MN44 revealed via detection of a circular shell with the Spitzer Space Telescope. First spectra taken in 2009 May-June showed the Balmer lines in emission as well as numerous emission lines of iron, which is typical of luminous blue variables (LBVs) near the visual…
Pulse-phase dependence of emission lines in the X-ray pulsar 4U 1626-67
Paul, Biswajit; Beri, Aru; Dewangan, Gulab C.
We present results from a pulse-phase-resolved spectroscopy of the complex emission lines around 1 keV in the unique accretion-powered X-ray pulsar 4U 1626-67, using the observation made with XMM-Newton in 2003. In this source, the redshifted and blueshifted emission lines and the linewidths measured earlier with Chandra suggest their accretion-di…
A Spitzer/IRAC characterization of Galactic AGB and RSG stars
Fazio, Giovanni G.; Reiter, Megan; Marengo, Massimo +1 more
We present new Spitzer/InfraRed Array Camera (IRAC) observations of 55 dusty long-period variables (48 asymptotic giant branch, AGB, and 6 red supergiant stars) in the Galaxy that have different chemistry, variability type, and mass-loss rate. O-rich AGB stars (including intrinsic S-type) tend to have redder [3.6]-[8.0] colours than carbon stars f…
Broad-band spectroscopy of the eclipsing high-mass X-ray binary 4U 1700-37 with Suzaku
Naik, Sachindra; Jaisawal, Gaurava K.
We present the results obtained from broad-band spectroscopy of the high-mass X-ray binary 4U 1700-37 using data from a Suzaku observation in 2006 September 13-14 covering 0.29-0.72 orbital phase range. The light curves showed significant and rapid variation in source flux during entire observation. We did not find any signature of pulsations in t…
Practical cosmology with lenses
Eales, S. A.
Surveys with submillimetre telescopes are revealing large numbers of gravitationally lensed high-redshift sources. I describe how, in practice, these lensed systems could be simultaneously used to estimate the values of cosmological parameters, test models for the evolution of the distribution of dark-matter haloes and investigate the properties o…
Radial alignment of elliptical galaxies by the tidal force of a cluster of galaxies
Rong, Yu; Zhang, Shuang-Nan; Yi, Shu-Xu +1 more
Unlike the random radial orientation distribution of field elliptical galaxies, galaxies in a cluster are expected to point preferentially towards the centre of the cluster, as a result of the cluster's tidal force on its member galaxies. In this work, an analytic model is formulated to simulate this effect. The deformation time-scale of a galaxy …
Discovery of very high energy γ-ray emission from the blazar 1ES 0033+595 by the MAGIC telescopes
Maraschi, L.; Covino, S.; Antonelli, L. A. +159 more
The number of known very high energy (VHE) blazars is ∼50, which is very small in comparison to the number of blazars detected in other frequencies. This situation is a handicap for population studies of blazars, which emit about half of their luminosity in the γ-ray domain. Moreover, VHE blazars, if distant, allow for the study of the environment…