Search Publications
'Distance mapping' and the 3D structure of BD +30° 3639
Akras, S.; Steffen, W.
BD +30° 3639 is a member of a group of uncommon planetary nebulae with Wolf-Rayet central star and higher expansion velocities in [O III] than in [N II] lines. Images and high-resolution spectra from the literature are used in order to construct a 3D model of the nebula using the morpho-kinematic code SHAPE. We find that two homologous expansion l…
Revised and updated catalogue of the First Byurakan Survey of late-type stars
Gigoyan, K. S.; Mickaelian, A. M.
There have been 15 lists of late-type stars published between 1990 and 2010. These late-type stars have been found in the low-dispersion spectroscopic plates of the First Byurakan Survey (FBS). The systematic search and selection was carried out on a surface ∼16 000 deg2 on almost the whole area of the FBS. As a result, a comprehensive …
Joint spectral-timing modelling of the hard lags in GX 339-4: constraints on reflection models
Wilms, J.; Uttley, P.; Cassatella, P. +1 more
The X-ray variations of hard state black hole X-ray binaries above 2 keV show 'hard lags', in that the variations at harder energies follow variations at softer energies, with a time lag τ depending on frequency ν approximately as τ∝ν-0.7. Several models have so far been proposed to explain this time delay, including fluctuations propag…
Triaxiality, principal axis orientation and non-thermal pressure in Abell 383
Limousin, Marceau; Morandi, Andrea
While clusters of galaxies are regarded as one of the most important cosmological probes, the conventional spherical modelling of the intracluster medium and the dark matter (DM), and the assumption of strict hydrostatic equilibrium (i.e. the equilibrium gas pressure is provided entirely by thermal pressure) are very approximate at best. Extending…
The nuclear polycyclic aromatic hydrocarbon emission of merger system NGC 1614: rings within rings
Reunanen, Juha; Väisänen, Petri; Zijlstra, Albert A. +2 more
It is important to understand the interplay between nuclear star formation and nuclear activity when studying the evolution of gas-rich galaxy mergers. We present here new spatially resolved L-band integral field unit observations of the inner kpc of the luminous infrared galaxy NGC 1614. A broad ring of 3.3-µm polycyclic aromatic hydrocarbo…
The origin of hot white dwarf circumstellar features
Barstow, M. A.; Redfield, S.; Welsh, B. Y. +4 more
We have analysed a sample of 23 hot DAs to better understand the source of the circumstellar features reported in previous work. Unambiguous detections of circumstellar material are again made at eight stars. The velocities of the circumstellar material at three of the white dwarfs are coincident with the radial velocities of interstellar medium (…
A search for pre-substellar cores and proto-brown dwarf candidates in Taurus: multiwavelength analysis in the B213-L1495 clouds
de Gregorio-Monsalvo, I.; Eiroa, C.; Bayo, A. +9 more
In anattempt to study whether the formation of brown dwarfs (BDs) takes place as a scaled-down version of low-mass stars, we conducted Institut de Radioastronomie Millimetrique (IRAM) 30 m/MAMBO-II observations at 1.2 mm in a sample of 12 proto-BD candidates selected from Spitzer/IRAC data in the B213-L1495 clouds in Taurus. Subsequent observation…
Detailed Sunyaev-Zel'dovich study with AMI of 19 LoCuSS galaxy clusters: masses and temperatures out to the virial radius
AMI Consortium; Olamaie, Malak; Rodríguez-Gonzálvez, Carmen +15 more
We present detailed 16-GHz interferometric observations using the Arcminute Microkelvin Imager (AMI) of 19 clusters with LX > 7 × 1037 W (h50 = 1) selected from the Local Cluster Substructure Survey (LoCuSS; 0.142 ≤ z ≤ 0.295) and of Abell 1758b, which is in the field of view of Abell 1758a. We detect and resolv…
The structure of star clusters in the outer halo of M31
Chapman, S.; Davies, M. B.; Mackey, A. D. +11 more
We present a structural analysis of halo star clusters in M31 based on deep Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) imaging. The clusters in our sample span a range in galactocentric projected distance from 13 to 100 kpc and thus reside in rather remote environments. Ten of the clusters are classical globulars, whilst four a…
Galaxy alignments in very X-ray luminous clusters at z > 0.5
Hung, Chao-Ling; Ebeling, Harald
We present the results of a search for galaxy alignments in 12 galaxy clusters at z > 0.5, a statistically complete subset of the very X-ray luminous clusters from the MAssive Cluster Survey (MACS). Using high-quality images taken with the Hubble Space Telescope (HST) that render measurement errors negligible, we find no radial galaxy alignment…