Search Publications
Constraints on the abundance of solid O_2 in dense clouds from ISO-SWS and ground-based observations
Burgdorf, M.; van Dishoeck, E. F.; Whittet, D. C. B. +9 more
The Short Wavelength Spectrometer (SWS) on-board the Infrared Space Observatory (ISO) has been used to search for solid O_2 in cold dense clouds at 6.45 mu m. Additional constraints on the O_2 abundance are obtained from analysis of the 4.67 mu m solid CO absorption profile observed from the ground. We derive upper limits of 50% and 100% of solid …
Coronagraph observations of inflows during high solar activity
Simnett, G. M.; Howard, R. A.; Sheeley, N. R., Jr. +2 more
Since the start of the SOHO mission three years ago, the Large Angle Spectrometric Coronagraph (LASCO) has recorded numerous examples of small, faint features moving inward through the corona. The inflows are observed at heliocentric distances of 2-4 Rs and became increasingly common during 1998, as solar and coronal mass ejection (CME)…
The pattern speed of the bar in NGC 4596
Gerssen, Joris; Kuijken, Konrad; Merrifield, Michael R.
The pattern speed is a defining parameter of any barred galaxy. A large number of model-dependent techniques have therefore been developed to derive the pattern speed. However, the only model-independent technique for measuring this quantity - the Tremaine-Weinberg method - has hitherto been applied to just one case, the SB0 galaxy NGC 936. In thi…
GHRS Observations of the White Dwarf in U Geminorum
Gilliland, Ronald L.; Long, Knox S.
We have observed the dwarf nova U Geminorum while it was in quiescence in the wavelength range 1162-1448 Å using the GHRS on Hubble Space Telescope. The time-resolved (λ/δλ=2000) spectra are dominated by the white dwarf in the system. By analyzing the Doppler shifts of the photospheric metal absorption lines that punctuate the spectrum, we have ac…
Radio signatures of a fast coronal mass ejection development on November 6, 1997
Schwenn, R.; Pick, M.; Vourlidas, A. +3 more
The Oporto radiospectrograph and the Nançay radioheliograph recorded a radio event on November 6, 1997, closely related in time with a flare on National Oceanic and Atmospheric Administration (NOAA) active region 8100. At the beginning of the event the radio sources are located on a rather small volume in the vicinity of the flare site. In a times…
NICMOS and VLA Observations of the Gravitationally Lensed Ultraluminous BAL Quasar APM 08279+5255: Detection of a Third Image
Lewis, Geraint F.; Ibata, Rodrigo A.; Irwin, Michael J. +2 more
We present a suite of observations of the recently identified ultraluminous BAL quasar APM 08279+5255, taken both in the infrared with the NICMOS high-resolution camera on board the Hubble Space Telescope and at 3.5 cm with the Very Large Array. With an inferred luminosity of ~5x1015 Lsolar, APM 08279+5255 is apparently the m…
Infrared spectroscopy of young supernova remnants heavily interacting with the interstellar medium. I. Ionized species in RCW 103
Lutz, D.; Sturm, E.; Oliva, E. +2 more
ISO spectral observations of the supernova remnant RCW103 are presented. This object is the prototype of relatively young remnants ( ~ 10(3) yr) with fast shocks (v_s ~ 1000 km s(-1) ) interacting with dense interstellar medium. The spectrum is dominated by prominent lines of [NeII], [SiII], [FeII] and other low excitation species which provide, f…
Indications on the binary nature of individual stars derived from a comparison of their HIPPARCOS proper motions with ground-based data. I. Basic principles
Wielen, R.; Dettbarn, C.; Jahreiß, H. +2 more
We present a method which provides some information on the possible binary nature of an apparently single star. The method compares the instantaneously measured HIPPARCOS proper motion with the long-term averaged, ground-based proper motion or with the proper motion derived from old ground-based positions and the HIPPARCOS position. Good sources f…
Molecular Gas in the Powerful Radio Nucleus of the Ultraluminous Infrared Galaxy PKS 1345+12
Sanders, D. B.; Scoville, N. Z.; Evans, A. S. +2 more
Millimeter CO (1 --> 0) interferometry and high-resolution, Hubble Space Telescope 1.1, 1.6, and 2.2 µm imaging of the radio compact galaxy PKS 1345+12 are presented. With an infrared luminosity of ~2×1012 Lsolar, PKS 1345+12 is a prime candidate for studying the link between the ultraluminous infrared galaxy phenome…
A study of extreme ultraviolet blinker activity
Harrison, R. A.; Innes, D. E.; Brooks, D. H. +1 more
In a previous paper (Harrison, 1997a), we reported on the existence of extreme ultraviolet (EUV) flashes, known as blinkers, which were identified in the quiet Sun network using the CDS instrument on board the Solar and Heliospheric Observatory. Since then a number of dedicated observations have been made and we report here on an analysis of 97 bl…