Search Publications
ISOCAM in flight.
Altieri, B.; Aussel, H.; Elbaz, D. +63 more
ISOCAM, the camera on-board ISO, takes images of the sky in the wavelength range 2.5 to 18µm. It features two independent channels, containing each a 32x32 pixel detector: the short wavelength channel, 2.5 to 5.5µm, and the long wavelength channel, 4 to 18µm. Each channel features 10 or 11 discrete band pass filters and CVFs with…
Hubble Space Telescope Observations of the Lensing Cluster Abell 2218
Smail, I.; Kneib, J. -P.; Ellis, R. S. +2 more
We present a striking new Hubble Space Telescope (HST) observation of the rich cluster Abell 2218 taken with the Wide Field Planetary Camera 2. HST's restored image quality reveals a sizable number of gravitationally lensed features in this cluster, significantly more than bad been identified by using ground-based telescopes. The brightest arcs ar…
Hubble Space Telescope Observations of the Disk and Jet of HH 30
Ballester, Gilda E.; Krist, John E.; Crisp, David +13 more
HH 30 in Taurus has been imaged with the Hubble Space Telescope WFPC2. The images show in reflected light a flared disk with a radius of about 250 AU that obscures the protostar. The disk resembles detailed accretion disk models that constrain its density distribution and show that its inclination is less than 100. There are bipolar emission-line …
The ISO Long-Wavelength Spectrometer.
Omont, A.; Ade, P. A. R.; Liseau, R. +60 more
The Long-Wavelength Spectrometer (LWS) is one of two complementary spectrometers aboard the European Space Agency's Infrared Space Observatory (ISO) (Kessler et al., 1996A&A...315L..49D). It operates over the wavelength range 43-196.9µm at either medium (about 150 to 200) or high (6800 to 9700) spectral resolving power. This Letter descr…
On the Automatic Determination of Light-Curve Parameters for Cepheid Variables
Stetson, Peter B.
A computerized algorithm for the automatic detection of Cepheid variables and for the estimation of their periods, amplitudes, and mean magnitudes from sparse data sets is presented. It is intended to be suitable for use in such programs as the measurement of Cepheid distances to external galaxies, for example with the Hubble Space Telescope. The …
The Morphologies of Distant Galaxies. II. Classifications from the Hubble Space Telescope Medium Deep Survey
Glazebrook, Karl; Ellis, Richard S.; Abraham, Roberto G. +4 more
The morphological properties of high-redshift galaxies are investigated using a sample of 507 objects (I < 22.0 mag) from the Hubble Space Telescope (HST) Medium Deep Survey. Independent visual morphological classifications for each galaxy are used to quantify the statistical uncertainties in the galaxy classifications. Visual classifications a…
Comparative Analysis of the High- and Low-Ionization Lines in the Broad-Line Region of Active Galactic Nuclei
Marziani, P.; Moles, M.; Sulentic, J. W. +2 more
We present the first comparative study of high- and low-ionization lines in a large sample of active galactic nuclei (AGNs). We report measurements of C IV λ1549, HeII λ1640, and O III] λ1663 paired to measurements of Hβ, HeII λ4686, and Fe II_opt_ in 52 low-redshift AGNs (z <~0.8). Ultraviolet archival spectra covering the region of C IV λ1549…
Interstellar pickup ions and quasi-perpendicular shocks: Implications for the termination shock and interplanetary shocks
Zank, G. P.; Webb, G. M.; Pauls, H. L. +1 more
A new mechanism for the acceleration of pickup ions by repeated reflections from the electrostatic cross shock potential of a quasi-perpendicular shock is presented. The acceleration mechanism, multiply reflected ion (MRI) acceleration, offers a resolution to the issue of injecting pickup ions into an efficient particle energization scheme, and th…
Hubble Space Telescope WFPC2 Imaging of M16: Photoevaporation and Emerging Young Stellar Objects
Holtzman, J. A.; Faber, S. M.; Ewald, S. P. +20 more
We present Hubble Space Telescope WFPC2 images of elephant trunks in the H II region M16. There are three principle results of this study. First, the morphology and stratified ionization structure of the interface between the dense molecular material and the interior of the H II region is well understood in terms of photoionization of a photoevapo…
Direct Imaging of Circumstellar Disks in the Orion Nebula
McCaughrean, Mark J.; O'Dell, C. Robert
Recent surveys of the Orion Nebula with the Hubble Space Telescope have revealed a number of stars surrounded by dark silhouettes seen projected against the bright background H II region. In this paper, we present a detailed analysis of HST and ground-based observations of the six most distinct silhouettes. We find a variety of morphologies, all c…