Search Publications
What obscures low-X-ray-scattering active galactic nuclei
Hönig, S. F.; Gandhi, P.; Asmus, D. +4 more
X-ray surveys have revealed a new class of active galactic nuclei (AGN) with a very low observed fraction of scattered soft X-rays, fscat <0.5 per cent. Based on X-ray modelling, these `X-ray new-type', or low observed X-ray-scattering (hereafter, `low-scattering') sources have been interpreted as deeply buried AGN with a high coveri…
The Galactic plane at faint X-ray fluxes - II. Stacked X-ray spectra of a sample of serendipitous XMM-Newton sources
Pérez-Ramírez, D.; Warwick, R. S.; Byckling, K.
We have investigated the X-ray spectral properties of a sample of 138 X-ray sources detected serendipitously in XMM-Newton observations of the Galactic plane, at an intermediate to faint flux level. We divide our sample into five subgroups according to the spectral hardness of the sources, and stack (i.e. co-add) the individual source spectra with…
Photometric studies of Abell 1664: the subtle effect a minor merger has on cluster galaxies
Pimbblet, Kevin A.; Owers, Matt S.; Jones, D. Heath +2 more
A combination of BRI photometry and archival Chandra X-ray data have been used to analyse the effects a minor merger has on the galaxy population of A1664. We utilize adaptive smoothing techniques in the 2D spatial distribution of cluster galaxies to reveal substructure ∼800 kpc south of the cluster core. We identify this substructure as most like…
Colour matters: the effects of lensing on the positional offsets between optical and submillimetre galaxies in Herschel-ATLAS
Ivison, R. J.; de Zotti, G.; González-Nuevo, J. +9 more
We report an unexpected variation in the positional offset distributions between Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) submillimetre (submm) sources and their optical associations, depending on both 250-µm signal-to-noise ratio and 250/350-µm colour. We show that redder and brighter submm sources have optical ass…
Discovery of a new Wolf-Rayet star and a candidate star cluster in the Large Magellanic Cloud with Spitzer
Gruendl, R. A.; Sander, A.; Hamann, W. -R. +8 more
We report the first-ever discovery of a Wolf-Rayet (WR) star in the Large Magellanic Cloud via detection of a circular shell with the Spitzer Space Telescope. Follow-up observations with Gemini-South resolved the central star of the shell into two components separated from each other by ≈2 arcsec (or ≈0.5 pc in projection). One of these components…
Revealing a new symbiotic X-ray binary with Gemini Near-infrared Integral Field Spectrograph
Bahramian, Arash; Heinke, Craig O.; Wijnands, Rudy +3 more
We use K-band spectroscopy of the counterpart to the rapidly variable X-ray transient XMMU J174445.5-295044 to identify it as a new symbiotic X-ray binary. XMMU J174445.5-295044 has shown a hard X-ray spectrum (we verify its association with an INTEGRAL/Imager on-Board the INTEGRAL Satellite 18-40 keV detection in 2013 using a short Swift/X-Ray Te…
Multiscale analysis of Galactic dust emission using complex wavelet transforms - I. Separation of Gaussian and non-Gaussian fluctuations in Herschel observations
Miville-Deschênes, M. -A.; Joncas, G.; Robitaille, J. -F.
We use anisotropic complex wavelet transforms to make a multiscale analysis of the distribution of fluctuations of dust emission at 250 µm from the Herschel infrared Galactic Plane Survey of the Herschel Space Observatory. By reproducing the Fourier power spectrum with complex wavelet transforms we show that different power distributions at …
Extended star clusters in NGC 1023 from HST/ACS mosaic imaging
Spitler, Lee R.; Forbes, Duncan A.; Pota, Vincenzo +1 more
Faint fuzzies (FFs) are a relatively new class of star cluster, first found in the nearby S0 galaxy NGC 1023 by Larsen & Brodie using Wide Field Planetary Camera 2 (WFPC2) images from the Hubble Space Telescope (HST). Here, we investigate the star cluster system of NGC 1023 using an eight pointing mosaic of Advanced Camera for Surveys (ACS) im…
GRB 051008: a long, spectrally hard dust-obscured GRB in a Lyman-break galaxy at z ≈ 2.8
Klose, S.; Stecklum, B.; Kann, D. A. +17 more
We present observations of the dark gamma-ray burst GRB 051008 provided by Swift/BAT, Swift/XRT, Konus-WIND, INTEGRAL/SPI-ACS in the high-energy domain and the Shajn, Swift/UVOT, Tautenburg, NOT, Gemini and Keck I telescopes in the optical and near-infrared bands. The burst was detected only in gamma- and X-rays and neither a prompt optical nor a …
The first source counts at 18 µm from the AKARI NEP Survey
Im, M.; Lee, H. M.; Serjeant, S. +9 more
We present the first galaxy counts at 18 µm using the Japanese AKARI satellite's survey at the North Ecliptic Pole (NEP), produced from the images from the NEP-Deep and NEP-Wide surveys covering 0.6 and 5.8 deg2, respectively. We describe a procedure using a point source filtering algorithm to remove background structure and a min…