Search Publications
Characterizing the Adaptive Optics Off-Axis Point-Spread Function. II. Methods for Use in Laser Guide Star Observations
Faber, S. M.; Gates, E. L.; Macintosh, B. A. +2 more
Most current astronomical adaptive optics (AO) systems rely on the availability of a bright star to measure the distortion of the incoming wave front. Replacing the guide star with an artificial laser beacon alleviates this dependency on bright stars and therefore increases sky coverage, but it does not eliminate another serious problem for AO obs…
Near-Infrared Properties of Faint X-Ray Sources from NICMOS Imaging in the Chandra Deep Fields
Teplitz, Harry I.; McCarthy, Patrick J.; Malkan, Matthew A. +2 more
We measure the near-infrared properties of 42 X-ray-detected sources from the Chandra Deep Fields North and South, the majority of which lie within the NICMOS Hubble Deep Field-North and Ultra Deep Field. We detect all 42 Chandra sources with NICMOS, with 95% brighter than H160=24.5. We find that X-ray sources are most often in the brig…
Hubble Space Telescope Imaging of the Ultracompact Blue Dwarf Galaxy HS 0822+3542: An Assembling Galaxy in a Local Void?
Somerville, Rachel S.; Windhorst, Rogier A.; Vacca, William D. +2 more
We present deep U-band, narrow V-band, and I-band images and photometry of the ultracompact blue dwarf galaxy HS 0822+3542 obtained with the Advanced Camera for Surveys/High Resolution Channel of the Hubble Space Telescope. This object is also extremely metal-poor [12+log(O/H)=7.45] and resides in a nearby void. The images resolve it into two phys…
Signs of warm-hot intergalactic medium in the soft X-ray background
Sołtan, A. M.; Freyberg, M. J.; Hasinger, G.
Small angular scale structure of the soft X-ray background correlated with the galaxy distribution is investigated. An extensive data sample from the ROSAT and XMM-Newton archives are used. Excess emission below 1 keV extending up to at least several hundred kpc around galaxies is detected. The relative amplitude of the excess emission in the 0.3-…
Chandra and HST Study of a New Transient X-Ray Source in M31
Williams, Benjamin F.; McClintock, Jeffrey E.; Murray, Stephen S. +2 more
We present X-ray and optical observations of a new transient X-ray source in M31 first detected 2004 May 23 at R.A.=00h43m09.940s+/-0.65", decl.=41deg23'32.49"+/-0.66". The X-ray light curve shows two peaks separated by several months, reminiscent of many Galactic X-ray novae. The location and X-ray spec…
Late Stages of Stellar Evolution
Blommaert, Joris A. D. L.; Cami, Jan; Szczerba, Ryszard +1 more
A large fraction of ISO observing time was used to study the late stages of stellar evolution. Many molecular and solid state features, including crystalline silicates and the rotational lines of water vapour, were detected for the first time in the spectra of (post-)Asymptotic Giant Branch (AGB) stars. Their analysis has greatly improved our know…
Kinematics of ionized gas in the barred Seyfert galaxy NGC 4151
Mundell, C. G.; Pedlar, A.; Asif, M. W.
We have determined the structure and kinematics of ionized gas in the weak oval bar of the archetypal Seyfert 1 galaxy, NGC 4151, using the TAURUS Fabry-Perot interferometer to simultaneously map the distribution and kinematics of Hβ emission. We also present broad-band ultraviolet imaging of the host galaxy, obtained with XMM-Newton, which shows …
XMM-Newton observations of the Mouse, SLX 1744 299 and SLX 1744 300
Maeda, Yoshitomo; Pavlov, George G.; Mori, Hideyuki +2 more
We observed the radio and X-ray source G359.23-0.82, also known as "the Mouse", with XMM-Newton. The X-ray image of this object shows a point-like source at the Mouse's "head", accompanied by a "tail" that extends for about 40″ westward. The morphology is consistent with that observed recently with Chandra [Gaensler, B.M., van der Swaluw, E., Cami…
Cold dust in (some) high-z supernova host galaxies
Clements, D. L.; Farrah, D.; Fox, M. +3 more
We present deep submillimetre photometry for 14 galaxies at z= 0.5 that are hosts of Type Ia supernovae, with the aim of examining the evolution of dust mass and extinction in normal galaxies. We combine these results with our previous observations of 17 z~ 0.5 SN1a hosts to look for any evolution in the dust content of normal galaxies between z= …
Sub-arcsecond imaging of the radio continuum and neutral hydrogen in the Medusa merger
Aalto, S.; Beswick, R. J.; Hüttemeister, S. +1 more
We present sub-arcsecond, Multi-Element Radio Linked Interferometer (MERLIN) observations of the decimetre radio continuum structure and neutral hydrogen (Hi) absorption from the nuclear region of the starburst galaxy NGC 4194 (the Medusa Merger). The continuum structure of the central kiloparsec of the Medusa has been imaged, revealing a pair of …