Search Publications
Missions
Journals
Publication Years
The Slowly Expanding Envelope of CRL 618 Probed with HC3N Rotational Ladders
Phillips, T. G.; Cernicharo, J.; Goicoechea, J. R. +1 more
Lines from HC3N and isotopic substituted species in ground and vibrationally excited states produce crowded millimeter and submillimeter wave spectra in the C-rich protoplanetary nebula CRL 618. The complete sequence of HC3N rotational lines from J=9-8 to J=30-29 has been observed with the IRAM 30 m telescope toward this obje…
Solar cycle dependence of the apparent radius of the Sun
Noël, F.
Visual astrometric observations of the Sun covering the second and first part of solar cycles 22 and 23 respectively, have been carried out during the last 13 years with the Danjon astrolabe of Santiago, Chile. These observations give, among other solar parameters, an absolute value of the Sun's apparent radius. We report here the results obtained…
On the Temporal Relationship between Hα Filament Eruptions and Soft X-Ray Emissions
Schuck, P. W.; Chen, J.; Schwartz, I. B. +1 more
A technique for investigating the temporal relationship between Hα filament eruptions and soft X-ray flux is presented. The method is fast, simple, based on statistical measures, and requires no a priori knowledge regarding the location of the filaments on the solar disk. The method is used to study the filament eruption associated with a coronal …
A High-Speed Erupting-Prominence CME: A Bridge Between Types
Feynman, Joan; Ruzmaikin, Alexander
Several studies have indicated that there may be two distinct types of coronal mass ejections (CMEs); a high-velocity bright energetic type associated with flares, and a smaller slower less impressive type associated with erupting prominences. How valid is this distinction? We analyze a CME combining attributes of both types, a high-velocity brigh…
Homologous large-scale activity in solar eruptive events of 24-26 November 2000
Hudson, H. S.; Nitta, N. V.; Grechnev, V. V. +1 more
We study large-scale activity on the solar disk associated with a 24-26 November 2000 series of six recurrent major flares and "halo" coronal mass ejections (CMEs). The analysis is based mainly on the SOHO/EIT data, particularly by using properly rotated difference full-disk images with 12-min intervals at 195 Å as well as with 6-hour intervals at…
Correlation between speeds of coronal mass ejections and the intensity of geomagnetic storms
Wang, Haimin; Yurchyshyn, Vasyl; Abramenko, Valentyna
We studied the relationship between the projected speed of coronal mass ejections (CMEs), determined from a sequence of Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph Experiment (SOHO/LASCO) images, and the hourly averaged magnitude of the Bz component of the magnetic field in an interplanetary ejecta, as m…
Detection of Intergalactic He II Absorption at Redshift 3.5
Anderson, Scott F.; Schneider, Donald P.; York, Donald G. +5 more
The large number of quasars found in the Sloan Digital Sky Survey has allowed searches for elusive, clear lines of sight toward He II Lyα absorption, a sensitive probe of the intergalactic medium. The few known systems indicate that He II reionization occurs at z>3. We report the detection of a He II Lyα absorption edge in a quasar spectrum at …
Discovery of Massive Evolved Galaxies at z > 3 in the Hubble Ultra Deep Field
Chen, Hsiao-Wen; Marzke, Ronald O.
We have identified six early-type galaxies at z>2.8 in the central 5.76 arcmin2 Hubble Ultra Deep Field NICMOS region based on a pronounced broadband discontinuity between the NICMOS F110W and F160W bandpasses. These galaxies have red observed optical and near-infrared colors (ABF775W-ABF160W>=2) that cannot …
A Complete Atlas of Recalibrated Hubble Space Telescope Faint Object Spectrograph Spectra of Active Galactic Nuclei and Quasars. I. Pre-COSTAR Spectra
Koratkar, Anuradha P.; Evans, Ian N.
We have recalibrated all nonpolarimetric, pre-COSTAR, archival Hubble Space Telescope Faint Object Spectrograph UV and optical spectrophotometry of active galaxies and quasars in order to extract uniformly calibrated spectrophotometric data for further detailed scientific investigations. The raw archival spectra have been recalibrated using the la…
Lick Northern Proper Motion Program. III. Lick NPM2 Catalog
Monet, David G.; Hanson, Robert B.; Jones, Burton F. +1 more
The Lick Northern Proper Motion (NPM) program, a two-epoch (1947-1988) photographic survey of the northern two-thirds of the sky (δ>~-23deg), has measured absolute proper motions, on an inertial system defined by distant galaxies, for 378,360 stars in the magnitude range 8<~B<~18. The 1993 NPM1 Catalog contains 148,940 stars in…