Search Publications
3D mapping of the dense interstellar gas around the Local Bubble
Crifo, F.; Lallement, R.; Welsh, B. Y. +2 more
We present intermediate results from a long-term program of mapping the neutral absorption characteristics of the local interstellar medium, motivated by the availability of accurate and consistent parallaxes from the Hipparcos satellite. Equivalent widths of the interstellar NaI D-line doublet at 5890 Å are presented for the lines-of-sight toward…
A Wide-Field Hubble Space Telescope Study of the Cluster Cl 0024+16 at z = 0.4. I. Morphological Distributions to 5 Mpc Radius
Treu, Tommaso; Smail, Ian; Ellis, Richard S. +5 more
We describe a new wide-field Hubble Space Telescope survey of the galaxy cluster Cl 0024+16 (z~0.4) consisting of a sparsely sampled mosaic of 39 Wide Field Planetary Camera 2 images that extends to a cluster radius of ~5 Mpc. Together with extensive ground-based spectroscopy taken from the literature, augmented with over a hundred newly determine…
The INTEGRAL Science Data Centre (ISDC)
Strong, A. W.; Mereghetti, S.; Paltani, S. +17 more
The INTEGRAL Science Data Centre (ISDC) provides the INTEGRAL data and means to analyse them to the scientific community. The ISDC runs a gamma ray burst alert system that provides the position of gamma ray bursts on the sky within seconds to the community. It operates a quick-look analysis of the data within few hours that detects new and unexpec…
A Low-Mass Central Black Hole in the Bulgeless Seyfert 1 Galaxy NGC 4395
Filippenko, Alexei V.; Ho, Luis C.
NGC 4395 is one of the least luminous and nearest known type 1 Seyfert galaxies, and it also lacks a bulge. We present a Hubble Space Telescope (HST) I-band image of its nuclear region and Keck high-resolution (~8 km s-1) echelle spectra containing the Ca II near-infrared triplet. In addition to the unresolved point source, there is a n…
Prominence Eruptions and Coronal Mass Ejection: A Statistical Study Using Microwave Observations
Howard, R. A.; Gopalswamy, N.; Shibasaki, K. +3 more
We present the results of a statistical study of a large number of solar prominence events (PEs) observed by the Nobeyama Radioheliograph. We studied the association rate, relative timing, and spatial correspondence between PEs and coronal mass ejections (CMEs). We classified the PEs as radial and transverse, depending on whether the prominence mo…
Early SPI/INTEGRAL measurements of 511 keV line emission from the 4th quadrant of the Galaxy
Strong, A. W.; Gehrels, N.; Knödlseder, J. +18 more
We report the first measurements of the 511 keV line emission from the Galactic Centre (GC) region performed with the spectrometer SPI on the space observatory INTEGRAL (International Gamma-Ray Astrophysics Laboratory). Taking into account the range of spatial distribution models which are consistent with the data, we derive a flux of 9.9+4.7…
The Cosmic Lens All-Sky Survey - II. Gravitational lens candidate selection and follow-up
Pearson, T. J.; McKean, J. P.; Blandford, R. D. +19 more
We report the final results of the search for gravitationally lensed flat-spectrum radio sources found in the combination of CLASS (Cosmic Lens All-Sky Survey) and JVAS (Jodrell Bank VLA Astrometric Survey). VLA (Very Large Array) observations of 16503 sources have been made, resulting in the largest sample of arcsec-scale lens systems available. …
Evidence for the Formation of a Large-Scale Current Sheet in a Solar Flare
Holman, Gordon D.; Sui, Linhui
We present X-ray evidence for the formation of a large-scale current sheet in a flare observed by the Ramaty High-Energy Solar Spectroscopic Imager on 2002 April 15. The flare occurred on the northwest limb, showing a cusp-shaped flare loop in the rise phase. When the impulsive rise in hard X-rays (>25 keV) began, the cusp part of the coronal s…
Detection of Nine M8.0-L0.5 Binaries: The Very Low Mass Binary Population and Its Implications for Brown Dwarf and Very Low Mass Star Formation
Close, Laird M.; Biller, Beth; Siegler, Nick +1 more
Use of the highly sensitive Hokupa'a/Gemini curvature wave front sensor has allowed direct adaptive optics (AO) guiding on very low mass (VLM) stars with SpT = M8.0-L0.5. A survey of 39 such objects detected nine VLM binaries (seven of which were discovered for the first time to be binaries). Most of these systems are tight (separation <5 AU) a…
Shapelets - I. A method for image analysis
Refregier, Alexandre
We present a new method for the analysis of images, a fundamental task in observational astronomy. It is based on the linear decomposition of each object in the image into a series of localized basis functions of different shapes, which we call `shapelets'. A particularly useful set of complete and orthonormal shapelets is that consisting of weigh…