Search Publications
Is There a 1998bw-like Supernova in the Afterglow of Gamma-Ray Burst 011121?
Dar, Arnon; Dado, Shlomo; De Rújula, A.
We use the very simple and successful cannonball model of gamma-ray bursts (GRBs) and their afterglows (AGs) to analyze the observations of the strongly extinct optical AG of the relatively nearby GRB 011121; these observations were made with ground-based telescopes at early times and with the Hubble Space Telescope at later times. We show that GR…
A Proper-Motion Survey for White Dwarfs with the Wide Field Planetary Camera 2
Alcock, C.; Axelrod, T. S.; Cook, K. H. +2 more
We have performed a search for halo white dwarfs as high proper motion objects in a second-epoch Wide Field Planetary Camera 2 image of the Groth-Westphal strip. The survey covers 74.8 arcmin2 and is complete to V~26.5. We identify 24 high proper motion objects with µ>0.014" yr-1. Five of these high proper motion obj…
Detection of Two Binary Trans-Neptunian Objects, 1997 CQ29 and 2000 CF105, with the Hubble Space Telescope
Buie, Marc W.; Noll, Keith S.; Stephens, Denise C. +6 more
Images of the trans-Neptunian objects 1997 CQ29 and 2000 CF105 obtained with the Hubble Space Telescope WFPC2 camera show them to be binary. The two components of 1997 CQ29 were separated in our images by 0.20"+/-0.03" in 2001 November and by 0.33"+/-0.01" in 2002 June/July. The corresponding minimum physical dista…
Sungrazing Comets: Properties of Nuclei and in Situ Detectability of Cometary Ions at 1 AU
Bochsler, P.; Küppers, M.; Benz, W. +1 more
A one-dimensional sublimation model for cometary nuclei is used to derive size limits for the nuclei of sungrazing comets and to estimate oxygen ion fluxes at 1 AU from their evaporation. Given that none of the ≈300 sungrazers detected by the SOlar and Heliospheric Observatory (SOHO) was observed after disappearing behind the sun, and that small n…
BL Lac identification for the ultraluminous X-ray source observed in the direction of NGC 4698
Palazzi, E.; Cappi, M.; Martini, P. +11 more
We report the identification of the optical and radio counterparts of the ultraluminous X-ray (ULX) source XMMU J124825.9+083020 (NGC 4698-ULX1). The optical spectrum taken with the VLT yields a redshift of z=0.43, which implies that the ULX is not associated with the nearby galaxy NGC 4698. The spectral energy distribution calculated from the ava…
Observations of Core Fallback during Coronal Mass Ejections
Sheeley, N. R., Jr.; Wang, Y. -M.
White-light observations made with the Large Angle and Spectrometric Coronagraph (LASCO) during the present solar maximum have revealed a multitude of faint, inward-moving features at heliocentric distances of r~2-6 Rsolar. Most of these structures appear to originate above r~3 Rsolar and may be signatures of the closing-down…
Solar Subsurface Flow Inferred Directly from Frequency-Wavenumber Correlations in the Seismic Velocity Field
Woodard, M. F.
We describe a general strategy for inverting helioseismic data for laterally inhomogeneous (aspherical) structure, in which the physical state of the solar interior is compared directly with inhomogeneity-induced correlations in the observable seismic wave field. The method was used to invert for subsurface supergranular-scale flow using Solar and…
Exploring the spectral properties of faint hard X-ray sources with XMM-Newton
Fiore, F.; Cappi, M.; Piconcelli, E. +3 more
We present a spectroscopic study of 41 hard X-ray sources detected serendipitously with high significance (>5sigma in the 2-10 keV band) in seven EPIC performance/verification phase observations. The large collecting area of EPIC allows us to explore the spectral properties of these faint hard X-ray sources with 2 < F2-10 < 80 …
On the X-Ray Source Luminosity Distributions in the Bulge and Disk of M31: First Results from the XMM-Newton Survey
Mason, Keith O.; Cordova, France A.; Trudolyubov, Sergey P. +2 more
We present luminosity distributions for the X-ray sources detected with XMM-Newton in the bulge and disk of the Andromeda galaxy (M31). The disk is clearly lacking the bright sources that dominate X-ray emission from the bulge. This is the first convincing evidence of a difference between bulge and disk X-ray populations in M31. Our results are in…
Properties of ultraviolet lines observed with the Coronal Diagnostic Spectrometer (CDS/SOHO) in coronal holes and the quiet Sun
Solanki, S. K.; Brković, A.; Schühle, U. +4 more
We present an analysis of 14 ultraviolet emission lines belonging to different atoms and ions observed inside polar coronal holes and in the normal quiet Sun. The observations were made with the Coronal Diagnostic Spectrometer (CDS) onboard the Solar and Heliospheric Observatory (SOHO). This study extends previous investigations made with the Sola…