Search Publications
Luminosity Functions of Elliptical Galaxies at Z <1.2
Im, Myungshin; Griffiths, Richard E.; Ratnatunga, Kavan U. +1 more
The luminosity functions of E/S0 galaxies are constructed in three different redshift bins (0.2 < z < 0.55, 0.55 < z < 0.8, 0.8 < z < 1.2), using the data from the Hubble Space Telescope (HST) Medium Deep Survey and other HST surveys. These independent luminosity functions show the brightening in the luminosity of E/S0s by about …
SWS spectroscopy of the starburst galaxy NGC 3256.
Lutz, D.; Genzel, R.; Sturm, E. +10 more
We present 2.5-40µm ISO SWS spectra of the starburst galaxy NGC 3256. We have observed many fine-structure lines of various atomic species as well as three rotational transitions of molecular hydrogen. From the [SIII] 18µm/33µm line ratio we infer low electron densities of =~300cm^-3^ in the HII regions. The observed [NeIII]/[NeI…
Intercombinations and Allowed Transitions in O IV
Judge, P. G.; Brekke, P.; Brage, Tomas
We report on large-scale ab initio multiconfiguration Hartree-Fock calculations for important multiplets including the UV 0.01 multiplet, 2s22p2PJ-2s2p2 4Pj', in O IV. The resulting transition probabilities should be accurate to ±5%-10% for intersystem lines and 1% or better for per…
On the Nature of the Outer Rings around SN 1987A
Panagia, N.; Kirshner, R. P.; Garnavich, P. M. +3 more
We present recent Hubble Space Telescope (HST) Faint Object Spectrograph and ground-based spectroscopic observations of SN 1987A and its surroundings and discuss them in conjunction with HST Faint Object Camera and Wide Field Planetary Camera 2 narrowband imaging. We have determined the following properties of the outer rings around SN 1987A: (1) …
Detection of far-infrared rotational lines of water vapour toward W Hydrae.
Lutz, D.; de Graauw, T.; Feuchtgruber, H. +5 more
We report the first detection of thermal water vapour emission from a circumstellar outflow. We have observed four far-infrared rotational emission lines of water vapour and one water absorption feature toward the evolved star W Hydrae, using the Short Wavelength Spectrometer (SWS) of the Infrared Space Observatory (ISO). Three of the emission lin…
Spatial variation of >106 Mev proton fluxes observed during the Ulysses rapid latitude scan: Ulysses COSPIN/KET results
Kunow, H.; Wibberenz, G.; Heber, B. +5 more
The basic physical processes that lead to the long-term modulation of cosmic rays in the heliosphere have been known for many years. However, our knowledge of the relative importance of the various processes is still incomplete. Observations of cosmic rays at high latitudes can be used to improve our understanding of modulation processes. In this …
Star counts in the Hubble Deep Field: constraining galactic structure models.
Minniti, D.; de Marchi, G.; Méndez, R. A. +2 more
Stellar sources are identified in the Hubble Deep Field, and accurate colours and magnitudes are presented. The predictions of a Galactic star counts model are compared with the faint stellar counts in this field. The model reproduces the observations very well in the magnitude range 21.0 < V ≤ 26.4, while it overpredicts the counts by a factor…
Hourly variances of fluctuations in the heliospheric magnetic field out of the ecliptic plane
Balogh, A.; Horbury, T. S.; Forsyth, R. J. +1 more
Magnetic field fluctuations at high heliographic latitudes are discussed in terms of the latitude and radial dependence of their variances, as observed by the Ulysses spacecraft. The increased level of transverse fluctuations in fast solar wind flows from the polar coronal holes is similar to that found in high speed streams near the ecliptic. How…
Measurement of T Tauri Binaries Using the Hubble Space Telescope Fine Guidance Sensors
Simon, M.; Taff, L. G.; Holfeltz, S. T.
We report measurements of young star multiples in the Taurus star-forming region using the Fine Guidance Sensors (FGS) of the HST. Of the eight confirmed IR-discovered multiples, the FGS detected six in visible light: DF Tau, ZZ Tau, V928 Tau, Elias 12, HV Tau, and GN Tau. The V-band magnitudes of the components range from 12.1 to 16.4 mag, and th…
The interstellar D/H ratio toward G191-B2B from GHRS observations.
Ferlet, R.; Vidal-Madjar, A.; Lallement, R. +3 more
We have observed the DA white dwarf G191-B2B using HST-GHRS to measure the interstellar D/H ratio. In order to derive an accurate structure of the line of sight, we have observed and analysed using a profile fitting procedure the interstellar lines of MgII (2800. and FeII (2344. high resolution using the Echelle B grating, and SiII (1190... (1206.…