Search Publications
On-the-Disk Development of the Halo Coronal Mass Ejection on 1998 May 2
Thompson, B. J.; Pick, M.; Maia, D. +7 more
A halo coronal mass ejection (CME) was observed at 15:03 UT on 1998 May 2 by the Solar and Heliospheric Observatory Large-Angle Spectrometric Coronagraph. The observation of the CME was preceded by a major soft X-ray flare in NOAA Active Region 8210, characterized by a delta spot magnetic configuration and some activity in region 8214. A large tra…
Cepheid Calibration of the Peak Brightness of Type Ia Supernovae. XI. SN 1998aq in NGC 3982
Panagia, N.; Saha, A.; Macchetto, F. D. +4 more
Repeated imaging observations have been made of NGC 3982 with the Hubble Space Telescope between 2000 March and May, over an interval of 53 days. Images were obtained on 12 epochs in the F555W band and on five epochs in the F814W band. The galaxy hosted the Type Ia supernova (SN Ia) SN 1998aq. A total of 26 Cepheid candidates were identified, with…
Chandra Detection of a Hot Gaseous Corona around the Edge-on Galaxy NGC 4631
Lauroesch, James T.; Walterbos, Rene; Wang, Q. Daniel +2 more
We present a Chandra X-ray observation that shows, unambiguously for the first time, the presence of a giant diffuse X-ray-emitting corona around the edge-on disk galaxy NGC 4631. This corona, with a characteristic thermal temperature of (2-7)×106 K, extends as far as 8 kpc away from the galactic plane. The X-ray morphology resembles th…
The Ionization and Metallicity of the Intervening O VI Absorber at z=0.1212 in the Spectrum of H1821+643
Tripp, Todd M.; Stocke, John T.; Tumlinson, Jason +2 more
We use high-resolution UV spectra of the radio-quiet quasar (QSO) H1821+643 (zem=0.297), obtained with the Space Telescope Imaging Spectrograph (STIS) and the Far Ultraviolet Spectroscopic Explorer (FUSE), to study the ionization and metallicity of an intervening O VI absorption line system at zabs=0.1212. This absorber has t…
A Pair of Compact Red Galaxies at Redshift 2.38, Immersed in a 100 Kiloparsec Scale Lyα Nebula
Teplitz, Harry I.; Kimble, Randy A.; Sutherland, Ralph S. +12 more
We present Hubble Space Telescope and ground-based observations of a pair of galaxies at a redshift of 2.38, which are collectively known as 2142-4420 B1. Both galaxies are luminous extremely red objects (EROs) and are separated by 0.8". They are embedded within a 100 kpc scale diffuse Lyα nebula (or blob) of luminosity ~1044 ergs s
Chandra Reveals the X-Ray Glint in the Cat's Eye
Guerrero, Martín A.; Chu, You-Hua; Gruendl, Robert A. +2 more
We have obtained Chandra ACIS-S observations of NGC 6543, the Cat's Eye Nebula. The X-ray emission from NGC 6543 is clearly resolved into a point source at the central star and diffuse emission confined within the central elliptical shell and two extensions along the major axis. Spectral analysis of the diffuse component shows that the abundances …
Blue Stragglers, Young White Dwarfs, and UV-Excess Stars in the Core of 47 Tucanae
Ferraro, Francesco R.; Paltrinieri, Barbara; Possenti, Andrea +2 more
We used a set of archived Hubble Space Telescope/WFPC2 images to probe the stellar population in the core of the nearby galactic globular cluster (GGC) 47 Tuc. From the ultraviolet (UV) color magnitude diagrams (CMDs) obtained for ~4000 stars detected within the Planetary Camera (PC) field of view we have pinpointed a number of interesting objects…
The White Dwarf Distance to the Globular Cluster 47 Tucanae and its Age
Zoccali, M.; Bragaglia, A.; Rich, R. M. +9 more
We present a new determination of the distance (and age) of the Galactic globular cluster 47 Tucanae (NGC 104) based on the fit of its white dwarf (WD) cooling sequence with the empirical fiducial sequence of local WD with known trigonometric parallax, following the method described by Renzini and collaborators. Both the cluster and the local WDs …
Proper Motions of the HH 111 Jet Observed with the Hubble Space Telescope
Hartigan, Patrick; Bally, John; Reipurth, Bo +2 more
New Hα and [S II] images of the HH 111 jet taken with the Hubble Space Telescope reveal marked proper motions and morphological changes when compared with similar images obtained 4 years earlier. Knots in the jet, which are dominated by emission from nested bow shocks, generally move ballistically, with no evidence for turbulent motions even in re…
A Hubble Space Telescope Lensing Survey of X-Ray Luminous Galaxy Clusters. I. A383
Smith, Graham P.; Smail, Ian; Kneib, Jean-Paul +2 more
We present an analysis of the mass distribution in the core of A383 (z=0.188), one of 12 X-ray luminous galaxy clusters at z~0.2 selected for a comprehensive and unbiased study of the mass distribution in massive galaxy clusters. Deep optical imaging performed by the Hubble Space Telescope (HST) reveals a wide variety of gravitationally lensed fea…