We calculate the expected number of strongly lensed radio sources in a sample of ∼ 6500 sources observed with the Very Large Array as part of the Cosmic Lens All Sky Survey (CLASS) during the first two sessions of its observations. A comparison between the predicted and the observed number of lensed radio sources allows a determination of the current value of Ωm − ΩΛ, where Ωm is the cosmologic...

Sky is among the subject matters frequently seen in photographs and useful for image understanding, processing, and retrieval. We propose a novel approach to sky detection based on color classification, region extraction, and physicsmotivated sky signature validation. First, the color classification is performed to generate a belief map of sky colored pixels. Next, connected components are extr...

Context. Several clusters of red supergiants have been discovered in a small region of the Milky Way close to the base of the ScutumCrux Arm and the tip of the Long Bar. Population synthesis models indicate that they must be very massive to harbour so many supergiants. Amongst these clusters, Stephenson 2, with a core grouping of 26 red supergiants, is a strong candidate to be the most massive ...

We have conducted an Hα survey of 38 0.77 z 1 galaxies over ∼100 arcmin2 of the Hubble Deep Field-North and Flanking Fields, to determine star formation rates (SFRs), with the near-IR multi-object spectrograph Cambridge Infrared Panoramic Survey Spectrograph (CIRPASS) on the William Herschel Telescope (WHT). This represents the first successful application of this technique to observing high-re...

We discuss the possibilities of extragalactic large-scale studies behind the Zone of Avoidance (ZOA) using complementary multiwavelength data from optical, systematic blind H I, and near-infrared (NIR) surveys. Applying these data to the NIR Tully –Fisher relation permits the mapping of the peculiar velocity field across the ZOA. Here, we present results of a comparison of galaxies identified i...

We present optical spectroscopy of three brown dwarf candidates identified in the first 1% of the DENIS sky survey. Low resolution spectra from 6430–9150Å show these objects to have similar spectra to the uncertain brown dwarf candidate GD 165B. High resolution spectroscopy shows that one of the objects – DBD 1228-1547 – has a strong 2.3±0.05Å equivalent width absorption line of Li I 6708Å, and...

We present the peculiar near-infrared spectrum of the newly discovered brown dwarf 2MASS J05185995−2828372, identified in the Two Micron All Sky Survey. Features characteristic of both L and T dwarfs are present, namely strong carbon monoxide absorption in K-band, strong methane absorption in Jand H-bands, and red near-infrared colors. We consider several scenarios that could produce these feat...

ALICE S. RYAN,1 DENIS C. MULLER,2 AND DARIUSH ELAHI1 1 Division of Gerontology, Department of Medicine, University of Maryland School of Medicine, and Geriatrics Service/Geriatric Research, Education, and Clinical Center, Baltimore Veterans Affairs Medical Center, Baltimore 21201; and 2Laboratory of Clinical Physiology, Gerontology Research Center, National Institute on Aging, Baltimore, Maryla...