Search Publications
SN 1987A's Circumstellar Envelope. II. Kinematics of the Three Rings and the Diffuse Nebula
Crotts, Arlin P. S.; Heathcote, Stephen R.
We present several different measurements of the velocities of structures within the circumstellar envelope of SN 1987A, including the inner, equatorial ring (ER), the outer rings (ORs), and the diffuse nebulosity at radii <~5 pc, based on CTIO 4 m and Hubble Space Telescope (HST) data. A comparison of STIS and WFPC2 [N II] λ6583 loci for the r…
O-bearing Molecules in Carbon-rich Proto-Planetary Objects
Cernicharo, J.; Herpin, F.
We present Infrared Space Observatory long-wavelength spectrometer observations of the proto-planetary nebula CRL 618, a star evolving very fast toward the planetary nebula stage. In addition to the lines of 12CO, 13CO, HCN, and HNC, we report on the detection of H2O and OH emission together with the fine-structure…
Multiwavelength observations of N 66 in the SMC: unveiling photodissociation interfaces and star formation
Boulanger, F.; Contursi, A.; Maoli, R. +5 more
We present new observations of the major star-forming region N 66 in the Small Magellanic Cloud and of its surroundings, which add to those presented in Contursi et al. (\cite{Contursi99}, Paper I). High-sensitivity CO observations allowed the detection of molecular gas associated with the H i I region, for which a high-resolution image in [O iii …
A NICMOS Survey of Early-Type Galaxy Centers: The Relation Between Core Properties, Gas and Dust Content, and Environment
Bower, Gary A.; Quillen, A. C.; Stritzinger, M.
We present a NICMOS 1.6 µm imaging isophotal study of 27 early-type galaxies. Core galaxies have reduced ellipticity and boxiness near and within their core or break radius. This supports a core formation mechanism that mixes or scatters stars such as scattering caused by a binary black hole. We find the same trends between central surface b…
Chromospheric and Transition Region Internetwork Oscillations: A Signature of Upward-propagating Waves
Judge, P. G.; Hansteen, V. H.; Carlsson, M. +1 more
We analyze spectral time series obtained on 1997 April 25 with the SUMER instrument on SOHO. Line and continuum data near 1037 Å were acquired at a cadence of 16 s. This spectral region was chosen because it contains strong emission lines of C II, formed in the upper chromosphere/lower transition region; O VI, formed in the upper transition region…
Evaluation of solar energetic Fe charge states: effect of proton-impact ionization
Torsti, J.; Kocharov, L.; Kovaltsov, G. A. +1 more
We present the energy-dependent rates of ionization and recombination of energetic Fe ions in solar coronal plasma for the energy range from 0.01 to above 100 MeV nucleon-1. For the > 0.1 MeV n-1 ions, the energy dependencies become essential for both ionization and recombination processes. Ionization of the Fe projectile …
The Central Gas Systems of Early-Type Galaxies Traced by Dust Features, Based on the Hubble Space Telescope WFPC2 Archival Images
Takata, Tadafumi; Aoki, Kentaro; Watanabe, Masaru +2 more
We investigated the central gas systems of E/S0 galaxies by making use of the WFPC2 images in the Hubble Space Telescope archive. We searched for gas systems that were traced by the dust with a new method of making color excess images in F555W-F814W (V-I). Of 25 sample galaxies, we detected gas systems in 14 galaxies. The dust was newly detected i…
Luminous Infrared Galaxies. III. Multiple Merger, Extended Massive Star Formation, Galactic Wind, and Nuclear Inflow in NGC 3256
Taniguchi, Y.; Terlevich, R.; Lípari, S. +3 more
We report detailed evidence for multiple merger, extended massive star formation, galactic wind, and circular/noncircular motions in the luminous infrared galaxy NGC 3256, based on observations of high-resolution imaging (Hubble Space Telescope, ESO NTT), and extensive spectroscopic data (more than 1000 spectra, collected at Estación Astrofísica d…
Hubble Space Telescope Observations of the Large Magellanic Cloud Field around SN 1987A: Distance Determination with Red Clump and Tip of the Red Giant Branch Stars
Panagia, N.; Salaris, M.; Cassisi, S. +1 more
We have used Hubble Space Telescope (HST) WFPC2 multiband observations of a field around SN 1987A in the Large Magellanic Cloud to measure its distance from the Sun. The observations allowed us to carefully determine the interstellar extinction along the line of sight to a large number of stars and to measure the LMC distance by using two stellar …
The far-infrared emission of radio loud and radio quiet quasars
Wilkes, B. J.; Polletta, M.; Courvoisier, T. J. -L. +1 more
Continuum observations at radio, millimetre, infrared and soft X-ray energies are presented for a sample of 22 quasars, consisting of flat and steep spectrum radio loud, radio intermediate and radio quiet objects. The primary observational distinctions, among the different kinds of quasars in the radio and IR energy domains are studied using large…