Search Publications
The Mass, Baryonic Fraction, and X-Ray Temperature of the Luminous, High-Redshift Cluster of Galaxies MS 0451.6-0305
Donahue, Megan; Hughes, John P.; Gaskin, Jessica A. +3 more
We present new Chandra X-ray observations of the luminous and cosmologically significant X-ray cluster of galaxies, MS 0451.6-0305, at z=0.5386. Spectral imaging data for the cluster are consistent with an isothermal cluster of (10.0-10.6)+/-1.6 keV, with an intracluster Fe abundance of (0.32-0.40)+/-0.13 solar. The systematic uncertainties, arisi…
Long-duration hectometric type III radio bursts and their association with solar energetic particle (SEP) events
MacDowall, R. J.; Bougeret, J. L.; Lara, A. +3 more
It has recently been suggested by Cane et al. [2002] that a class of type III solar radio bursts, called type III-l, is reliably associated with intense solar energetic particle (SEP) events. They proposed that the causative electrons for these bursts are accelerated in regions of reconnecting magnetic field in the wakes of coronal mass ejections …
A Survey of 557 GHz Water Vapor Emission in the NGC 1333 Molecular Cloud
Bergin, Edwin A.; Kaufman, Michael J.; Melnick, Gary J. +2 more
Using NASA's Submillimeter Wave Astronomy Satellite (SWAS), we have examined the production of water in quiescent and shocked molecular gas through a survey of the 556.936 GHz 110-101 transition of ortho-H2O in the NGC 1333 molecular core. These observations reveal broad emission lines associated with the IRAS 2, I…
Target Selection for SETI. II. Tycho-2 Dwarfs, Old Open Clusters, and the Nearest 100 Stars
Turnbull, Margaret C.; Tarter, Jill C.
We present the full target list and prioritization algorithm developed for use by the microwave search for technological signals at the SETI Institute. We have included the Catalog of Nearby Habitable Stellar Systems (HabCat, described in Paper I), all of the nearest 100 stars and 14 old open clusters. This is further augmented by a subset of the …
Ks Number Counts in the Groth and Coppi Fields
Cardiel, Nicolás; Balcells, Marc; Gallego, Jesús +5 more
We have used William Herschel Telescope/INGRID Ks images on two high-latitude fields, the Coppi and Groth strips, to obtain galaxy number counts over ~180 arcmin2, to a depth of Ks~21.0. Detection efficiency corrections as a function of object size have been calculated on each pointing. We have used a signal-to-noi…
Spectral observations of transient features in the FUV Jovian polar aurora
Clarke, J. T.; Grodent, D.; Gustin, J. +2 more
Images of the Jovian FUV aurora show several morphologically and dynamically different regions. The main oval is usually fairly steady while the high-latitude emission inside the oval can vary over timescales of <1 min. We describe time and spatially resolved spectral observations of the Jovian aurora made with the Space Telescope Imaging Spect…
A Quadruple-Phase Strong Mg II Absorber at z ~ 0.9902 toward PG 1634+706
Charlton, Jane C.; Churchill, Christopher W.; Bond, Nicholas A. +2 more
The z=0.9902 system along the quasar PG 1634+706 line of sight is a strong Mg II absorber [Wr(λ2796)>0.3 Å] with only weak C IV absorption (it is ``C IV-deficient''). To study this system, we used high-resolution spectra from both the Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS) and the Keck I telescope High Res…
The central engines of radio-loud quasars
Ho, L. C.; Staubert, R.; Wang, J. -M.
We have assembled a sample of 37 radio-loud quasars that have been imaged with the Hubble Space Telescope in order to investigate their black hole masses, accretion rates, and the structure of their accretion disks. The black hole masses were estimated from the luminosities of the host galaxies, and the accretion powers were extrapolated from the …
A Point-Source Excess in Abell 1185: Intergalactic Globular Clusters?
Jordán, Andrés; Marzke, Ronald O.; Côté, Patrick +1 more
Deep imaging with WFPC2 and the Hubble Space Telescope has been used to search for a population of intergalactic globular clusters (GCs) belonging to A1185, a richness class I cluster at cz=9800 km s-1. The field is noteworthy in that contains no bright galaxies and yet is centered on the peak of the cluster's X-ray surface brightness d…
Test for Alfvén Wave Signatures in a Solar Coronal Hole
Moran, Thomas G.
Using spectral line observations to study minor ion motions in a solar coronal hole, a test was made for the presence of Alfvén waves. From this we conclude that the Alfvén wave flux into the upper portion of the hole is not significant. The SOHO/SUMER ultraviolet spectrograph was used to observe 22 coronal ions with masses ranging from 14mH<…