Search Publications
The physical properties of the HH 30 jet from HST and ground-based data
Bacciotti, Francesca; Eislöffel, Jochen; Ray, Thomas P.
We investigate the physical properties of the HH 30 jet by applying the spectroscopic diagnostic technique described in Bacciotti & Eislöffel (\cite{be99}) to ground-based spectra and Hubble Space Telescope (HST) calibrated emission-line images. We derive the variation along the beam of the ionization fraction xe, of the total hydro…
Cataclysmic Variables and a Candidate Helium White Dwarf in the Globular Cluster NGC 6397
Edmonds, Peter D.; Grindlay, Jonathan E.; Cool, Adrienne +3 more
We have used the Hubble Space Telescope (HST) and the Faint Object Spectrograph (FOS) to study faint UV stars in the core of the nearby globular cluster NGC 6397. We confirm the presence of a fourth cataclysmic variable (CV) in NGC 6397 (hereafter CV 4), and we use the photometry of Cool et al. to present evidence that CVs 1-4 all have faint disks…
Detection of Evolved High-Redshift Galaxies in Deep NICMOS/VLT Impages
Broadhurst, Tom; Rosati, Piero; Benítez, Narciso +2 more
A substantial population of high-redshift, early-type galaxies is detected in very deep UBVRIJHK images. Four elliptical profile galaxies are identified in the redshift range 1<z<2, with very red spectral energy distributions implying ages of >~2 Gyr for standard passive evolution. We also find later type IR-luminous galaxies at similarly…
Cyclotron resonance in coronal holes: 1. Heating and acceleration of protons, O5+, and Mg9+
Hollweg, Joseph V.
The resonant heating and acceleration of protons and selected heavy ions in coronal holes are investigated by calculating trajectories of individual test particles under the influence of gravity, the electrostatic electric field, the mirror force, and the resonant acceleration due to interaction with dispersive ion cyclotron waves. The transverse …
Optical imaging of the host galaxies of X-ray selected BL Lacertae objects
Falomo, Renato; Kotilainen, Jari K.
We investigate the properties of the host galaxies of X-ray selected (high frequency peaked) BL Lac objects using a large and homogeneous data set of high spatial resolution R-band observations of 52 BL Lacs in the EMSS and Slew samples. The redshift distribution of the BL Lacs ranges from z = 0.04 to z>0.7, with average and median redshifts z …
The chemical composition of the silicate dust around RAFGL7009S and IRAS 19110+1045
Cox, P.; Dartois, E.; Demyk, K. +2 more
We have studied the chemical composition of the silicates around the two massive protostellar objects RAFGL7009S (IRAS 18316-0602) and IRAS 19110+1045. The silicate features of both sources are similar. The position and shape of the 9.6 and 18 mu m silicate bands coincide with those of amorphous pyroxene-type silicates. We find that the silicate f…
Starburst in the Intragroup Medium of Stephan's Quintet
Xu, Cong; Sulentic, Jack W.; Tuffs, Richard
Based on new Infrared Space Observatory midinfrared observations and ground-based Hα and near-infrared observations, we report the detection of a bright starburst in the intragroup medium (IGM) of the famous compact group of galaxies known as Stephan's Quintet (source A in Fig. 1). We demonstrate that this starburst is caused by a colli…
The Host Galaxies of Three Radio-loud Quasars: 3C 48, 3C 345, and B2 1425+267
Schneider, Donald P.; Bahcall, John N.; Kirhakos, Sofia +1 more
Observations with the Wide-Field/Planetary Camera-2 of the Hubble Space Telescope are presented for three radio-loud quasars: 3C 48 (z=0.367), B2 1425+267 (z=0.366), and 3C 345 (z=0.594). All three quasars have luminous (~4×L*) galaxies as hosts, which are either elliptical (B2 1425+267 and 3C345) or interacting (3C 48), and all hosts a…
Quasars and Ultraluminous Infrared Galaxies: At the Limit?
McLeod, K. K.; Rieke, G. H.; Storrie-Lombardi, L. J.
We have detected the host galaxies of 16 nearby, radio-quiet quasars using images obtained with the Near-Infrared Camera and MultiObject Spectrometer. We confirm that these luminous quasars tend to live in luminous, early-type host galaxies, and we use the host-galaxy magnitudes to refine the luminosity/host-mass limit inferred from ground-based s…
Relation between Flare-associated X-Ray Ejections and Coronal Mass Ejections
Akiyama, Sachiko; Nitta, Nariaki
In an attempt to identify the direct signatures of coronal mass ejections (CMEs) in soft X-ray wavelengths, we have searched for plasma ejections in Yohkoh soft X-ray telescope (SXT) images in a total of 17 limb flares, and compared the results with the Solar and Heliospheric Observatory LASCO data. A general correlation exists between the presenc…