Search Publications
On the void explanation of the Cold Spot
Martínez-González, E.; Vielva, P.; Marcos-Caballero, A. +1 more
The integrated Sachs-Wolfe (ISW) contribution induced on the cosmic microwave background by the presence of a supervoid as the one detected by Szapudi et al. (2015) is reviewed in this letter in order to check whether it could explain the Cold Spot (CS) anomaly. Two different models, previously used for the same purpose, are considered to describe…
The JCMT Gould Belt Survey: evidence for radiative heating and contamination in the W40 complex
White, G. J.; Marsh, K.; Ward-Thompson, D. +56 more
We present SCUBA-2 450 µm and 850 µm observations of the W40 complex in the Serpens-Aquila region as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) of nearby star-forming regions. We investigate radiative heating by constructing temperature maps from the ratio of SCUBA-2 fluxes using a fixed dust opacity spect…
Observational aspects of galactic accretion at redshift 3.3
Rauch, Michael; Haehnelt, Martin G.; Becker, George D.
We investigate the origin of extragalactic continuum emission and its relation to the stellar population of a recently discovered peculiar z = 3.344 Ly α emitter. Based on an analysis of the broad-band colours and morphology, we find further support for the idea that the underlying galaxy is being fed by a large-scale (L ≥ 35 kpc) accretion stream…
Accretion disc/corona emission from a radio-loud narrow-line Seyfert 1 galaxy PKS 0558-504
Dewangan, G. C.; Ghosh, R.; Raychaudhuri, B.
Approximately 10-20 per cent of active galactic nuclei (AGN) are known to eject powerful jets from the innermost regions. There is very little observational evidence if the jets are powered by spinning black holes and if the accretion discs extend to the innermost regions in radio-loud AGN. Here, we study the soft X-ray excess, the hard X-ray spec…
Comparing Dark Energy Survey and HST-CLASH observations of the galaxy cluster RXC J2248.7-4431: implications for stellar mass versus dark matter
Benoit-Lévy, A.; D'Andrea, C. B.; Abbott, T. M. C. +66 more
We derive the stellar mass fraction in the galaxy cluster RXC J2248.7-4431 observed with the Dark Energy Survey (DES) during the Science Verification period. We compare the stellar mass results from DES (five filters) with those from the Hubble Space Telescope Cluster Lensing And Supernova Survey (CLASH; 17 filters). When the cluster spectroscopic…
Probing dark energy via galaxy cluster outskirts
Sun, Ming; Morandi, Andrea
We present a Bayesian approach to combine Planck data and the X-ray physical properties of the intracluster medium in the virialization region of a sample of 320 galaxy clusters (0.056 < z < 1.24, kT ≳ 3 keV) observed with Chandra. We exploited the high level of similarity of the emission measure in the cluster outskirts as cosmology proxy. …
A deep Chandra observation of the interacting star-forming galaxy Arp 299
Zezas, A.; Ballo, L.; Della Ceca, R. +1 more
We present results from a 90 ks Chandra ACIS-S observation of the X-ray luminous interacting galaxy system Arp 299 (NGC 3690/IC 694). We detect 25 discrete X-ray sources with luminosities above ∼4.0 × 1038 erg s-1 covering the entire Ultra Luminous X-ray source (ULX) regime. Based on the hard X-ray spectra of the non-nuclear …
The supermassive black hole and double nucleus of the core elliptical NGC 5419
Bender, Ralf; Thomas, Jens; Fabricius, Maximilian H. +5 more
We obtained adaptive-optics assisted SINFONI observations of the central regions of the giant elliptical galaxy NGC 5419 with a spatial resolution of 0.2 arcsec (≈55 pc). NGC 5419 has a large depleted stellar core with a radius of 1.58 arcsec (430 pc). HST and SINFONI images show a point source located at the galaxy's photocentre, which is likely …
X-rays beware: the deepest Chandra catalogue of point sources in M31
Barmby, P.; Vulic, N.; Gallagher, S. C.
This study represents the most sensitive Chandra X-ray point source catalogue of M31. Using 133 publicly available Chandra ACIS-I/S observations totalling ∼1 Ms, we detected 795 X-ray sources in the bulge, north-east, and south-west fields of M31, covering an area of ≈0.6 deg2, to a limiting unabsorbed 0.5-8.0 keV luminosity of ∼10…
The distribution of dark and luminous matter in the unique galaxy cluster merger Abell 2146
McNamara, Brian R.; Fabian, Andrew C.; Santana, Rebecca +9 more
Abell 2146 (z = 0.232) consists of two galaxy clusters undergoing a major merger. The system was discovered in previous work, where two large shock fronts were detected using the Chandra X-ray Observatory, consistent with a merger close to the plane of the sky, caught soon after first core passage. A weak gravitational lensing analysis of the tota…