Search Publications
Observational Constraints on Coronal Heating Models Using Coronal Diagnostics Spectrometer and Soft X-Ray Telescope Data
Schmelz, J. T.; Scopes, R. T.; Cirtain, J. W. +2 more
We have constructed a multithermal differential emission measure distribution for several pixels along a relatively isolated coronal loop on the southwest limb of the solar disk using spectral line data from the Solar and Heliospheric Observatory coronal diagnostics spectrometer (CDS) and broadband data from the Yohkoh soft X-ray telescope. The te…
Source Regions of Coronal Mass Ejections
Dere, K. P.; Subramanian, Prasad
Observations of the solar corona with the Large Angle and Spectrometric Coronagraph Experiment (LASCO) and EUV Imaging Telescope (EIT) instruments on the Solar and Heliospheric Observatory (SOHO) provide an unprecedented opportunity to study coronal mass ejections (CMEs) from their initiation through their evolution out to 30 Rsolar. Th…
SOHO Observations of a Coronal Mass Ejection
Vourlidas, Angelos; Wu, R.; Raymond, John C. +5 more
We describe a coronal mass ejection (CME) observed on 1999 April 23 by the Ultraviolet Coronagraph Spectrometer (UVCS), the Extreme-Ultraviolet Imaging Telescope (EIT), and the Large-Angle and Spectrometric Coronagraphs (LASCO) aboard the Solar and Heliospheric Observatory (SOHO). In addition to the O VI and C III lines typical of UVCS spectra of …
Detection of Cosmic Shear with the Hubble Space Telescope Survey Strip
Refregier, Alexandre; Rhodes, Jason; Groth, Edward J.
Weak lensing by large-scale structure provides a unique method to directly measure matter fluctuations in the universe and has recently been detected from the ground. Here we report the first detection of this ``cosmic shear'' based on space-based images. The detection was derived from the Hubble Space Telescope (HST) Survey Strip (or ``Groth Stri…
The Proper Motion, Parallax, and Origin of the Isolated Neutron Star RX J185635-3754
Walter, Frederick M.
The isolated neutron star RX J185635-3754 is the closest known neutron star to the Sun. Based on Hubble Space Telescope Wide Field Planetary Camera 2 observations over a 3 yr baseline, I report its proper motion (332+/-1 mas yr-1 at a position angle of 100.3d+/-0.1d) and parallax (16.5+/-2.3 mas, 61 pc). This proper motion brings the ne…
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