Search Publications
Gamma-ray bursts from the early Universe: predictions for present-day and future instruments
Covino, S.; Campana, S.; Tagliaferri, G. +2 more
Long gamma-ray bursts (GRBs) are important for the study of the Universe near and beyond the epoch of reionization. In this paper, we describe the characteristics of an `ideal' instrument that can be used to search for GRBs at z >= 6-10. We find that the detection of these objects requires soft-band detectors with high sensitivity and a moderat…
The molecular polar disc in NGC 2768
Bureau, Martin; Crocker, Alison F.; Young, Lisa M. +1 more
We present CO(1-0) and CO(2-1) maps of the molecular polar disc in the elliptical galaxy NGC 2768 obtained at the Institute de Radioastronomie Millimétrique (IRAM) Plateau de Bure Interferometer. The maps have a resolution of and for the CO(1-0) and CO(2-1) lines, respectively. The CO maps complete the unique picture of the interstellar medium (IS…
Non-parametric strong lens inversion of Cl 0024+1654: illustrating the monopole degeneracy
de Rijcke, S.; Dejonghe, H.; Liesenborgs, J. +1 more
The cluster lens Cl 0024+1654 is undoubtedly one of the most beautiful examples of strong gravitational lensing, providing five large images of a single source with well-resolved substructure. Using the information contained in the positions and the shapes of the images, combined with the null space information, a non-parametric technique is used …
The nature of the ghost cavity in the NGC 741 group
Babul, Arif; Raychaudhury, Somak; Ponman, Trevor J. +4 more
We discuss the effects of energy injection into the intragroup medium of the group of galaxies associated with NGC 741. The X-ray emission reveals a large bubble, which in the absence of a currently bright central radio source may have been inflated by a previous cycle of nuclear activity. If the bubble is filled with a light, relativistic fluid, …
IGRJ16479-4514: the first eclipsing supergiant fast X-ray transient?
Campana, S.; Israel, G.; Stella, L. +2 more
Supergiant fast X-ray transients (SFXTs) are a new class of high-mass X-ray binaries recently discovered with INTEGRAL. Hours-long outbursts from these sources have been observed on numerous occasions at luminosities of ~1036-1037ergs-1, whereas their low-level activity at ~1032-1034ergs-…
A search for the most massive galaxies - II. Structure, environment and formation
Nichol, R. C.; Fritz, A.; Gebhardt, K. +3 more
We study a sample of 43 early-type galaxies, selected from the Sloan Digital Sky Survey (SDSS) because they appeared to have velocity dispersions of σ >= 350 km s-1. High-resolution photometry in the SDSS i passband using the High-Resolution Channel of the Advanced Camera for Surveys on board the Hubble Space Telescope shows that jus…
Earth X-ray albedo for cosmic X-ray background radiation in the 1-1000 keV band
Sunyaev, R.; Revnivtsev, M.; Sazonov, S. +1 more
We present calculations of the reflection of the cosmic X-ray background (CXB) by the Earth's atmosphere in the 1-1000 keV energy range. The calculations include Compton scattering and X-ray fluorescent emission and are based on a realistic chemical composition of the atmosphere. Such calculations are relevant for CXB studies using the Earth as an…
The measurement errors in the Swift-UVOT and XMM-OM
Kuin, N. P. M.; Rosen, S. R.
The probability of photon measurement in some photon-counting instrumentation, such as the Optical Monitor (OM) on the XMM-Newton satellite, and the Ultraviolet/Optical Telescope (UVOT) on the Swift satellite, does not follow a Poisson distribution due to the detector characteristics, but a binomial distribution. For a single-pixel approximation, …
Testing the galaxy cluster mass-observable relations at z = 1 with XMM-Newton and Chandra observations of XLSSJ022403.9-041328
Valtchanov, I.; Pierre, M.; Willis, J. +7 more
We present an analysis of deep XMM-Newton and Chandra observations of the z = 1.05 galaxy cluster XLSSJ022403.9-041328 (hereafter XLSSC029), detected in the XMM-Newton Large Scale Structure survey. Density and temperature profiles of the X-ray emitting gas were used to perform a hydrostatic mass analysis of the system. This allowed us to measure t…
TeV J2032+4130: a not-so-dark accelerator?
Rodriguez, J.; Finley, J. P.; Konopelko, A. +5 more
The HEGRA γ-ray source TeV J2032+4130 is considered the prototypical `dark accelerator', since it was the first TeV source detected with no firm counterparts at lower frequencies. The Whipple collaboration observed this source in 2003-05 and the emission hotspot appears displaced about 9 arcmin to the northeast of the HEGRA position, though given …