Search Publications
Localization of the X-ray source in the globular cluster G1 with Chandra
Barmby, P.; Heinke, C. O.; Cohn, H. N. +5 more
We report the most accurate X-ray position of the X-ray source in the giant globular cluster G1 in M31 by using the Chandra X-ray Observatory, Hubble Space Telescope (HST) and Canada-France-Hawaii Telescope (CFHT). G1 is clearly detected with Chandra and by cross-registering with HST and CFHT images, we derive a 1σ error radius of 0.15arcsec, sign…
The longest observation of a low-intensity state from a supergiant fast X-ray transient: Suzaku observes IGRJ08408-4503
Sidoli, L.; Esposito, P.; Ducci, L.
We report here on the longest deep X-ray observation of a supergiant fast X-ray transient (SFXT) outside outburst, with an average luminosity level of 1033 erg s-1 (assuming 3 kpc distance). This observation was performed with Suzaku in 2009 December and was targeted on IGRJ08408-4503, with a net exposure with the X-ray Imagi…
A blue tilt in the globular cluster system of the Milky Way-like galaxy NGC 5170
Bailin, Jeremy; Spitler, Lee R.; Forbes, Duncan A. +4 more
Here, we present Hubble Space Telescope/Advanced Camera for Surveys (ACS) imaging, in the B and I bands, of the edge-on Sb/Sc galaxy NGC 5170. Excluding the central disc region, we detect 142 objects with colours and sizes typical of globular clusters (GCs). Our main result is the discovery of a `blue tilt' (a mass-metallicity relation), at the 3σ…
Galaxies at a redshift of ~0.5 around three closely spaced quasar sightlines
Bechtold, Jill; Morris, Simon L.; Jannuzi, Buell T. +4 more
We examine the relationship between galaxies and the intergalactic medium at z < 1 using a group of three closely spaced background quasi-stellar objects (QSOs) with zem ~ 1 observed with the Hubble Space Telescope. Using a new grouping algorithm, we identify groups of galaxies and absorbers across the three QSO sightlines that may b…
The nuclear outflow in NGC 2110
Wilson, A. S.; Rosario, D. J.; Nelson, C. H. +1 more
We present a spectroscopic and optical/radio imaging study of the Seyfert NGC 2110 using the Hubble Space Telescope (HST)/Space Telescope Imaging Spectrograph (STIS), aiming to measure the dynamics and understand the nature of the nuclear outflow in the galaxy. Previous HST studies have revealed the presence of a linear structure in the narrow-lin…
The enigmatic young brown dwarf binary FUTau: accretion and activity
Scholz, A.; Micela, G.; Stelzer, B. +1 more
FUTau belongs to a rare class of young, wide brown dwarf binaries. We have resolved the system in a Chandra X-ray observation and detected only the primary, FUTauA. Hard X-ray emission, presumably from a corona, is present but, unexpectedly, we also detect a strong and unusually soft component from FUTauA. Its X-ray properties, so far unique among…
The spectral energy distribution of D-type symbiotic stars: the role of dust shells
Ciroi, S.; Rafanelli, P.; Angeloni, R. +1 more
We have collected continuum data of a sample of D-type symbiotic stars. By modelling their spectral energy distribution in a colliding-wind theoretical scenario we have found characteristics common to all the systems: (1) at least two dust shells are clearly present, one at ~1000K and the other at ~400K they dominate the emission in the infrared; …
Hyperluminous infrared galaxies from IIFSCz
Wang, Lingyu; Rowan-Robinson, Michael
We present a catalogue of 179 hyperluminous infrared galaxies (HLIRGs) from the Imperial IRAS-FSS Redshift (IIFSCz) Catalogue. Of the 92 with detections in at least two far-infrared bands, 62 are dominated by an M82-like starburst, 22 by an Arp 220-like starburst and eight by an active galactic nucleus (AGN) dust torus. On the basis of previous gr…
Spectroscopic identifications of SWIRE sources in ELAIS-N1
Valtchanov, I.; Morrison, G.; Georgakakis, A. +6 more
We present the largest spectroscopic follow-up performed in SWIRE ELAIS-N1. We were able to determine redshifts for 289 extragalactic sources. The values of spectroscopic redshifts of the latter have been compared with the estimated values from our photometric redshift code with very good agreement between the two for both galaxies and quasars. Si…
Infrared laboratory absorbance spectra of olivine: using classical dispersion analysis to extract peak parameters
Speck, A. K.; Dijkstra, C.; Pitman, K. M. +1 more
Laboratory measurements quantifying the effect of Fe substituting for Mg in olivine are needed to distinguish compositional from temperature, grain size and grain shape effects in observational data. To address this need, we study room temperature absorption spectra of a large suite of olivines evenly spaced across Mg and Fe compositions. We apply…