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Far-Ultraviolet Spectra of Starburst Galaxies: Stellar Population and the Kinematics of the Interstellar Medium
Ferguson, Henry C.; Robert, Carmelle; Heckman, Timothy +3 more
The far-ultraviolet spectra of the four starburst galaxies NGC 6090, Mrk 66, Mrk 1267, and IRAS 0833+6517 were observed with the Hopkins Ultraviolet Telescope during the Astro-2 mission. Additional data were obtained for IRAS 0833+6517 with the Goddard High-Resolution Spectrograph (GHRS) on the Hubble Space Telescope. We analyze the observations i…
Measurements of Solar Magnetic Element Dispersal
Berger, Thomas E.; Shine, Richard A.; Title, Alan M. +1 more
The dispersal of magnetic elements in the solar photospheric flow field is studied by tracking individual ``magnetic bright points'' (MBPs) identified in a G-band 4305 Å filtergram time series obtained at the 50 cm Swedish Vacuum Solar Telescope on La Palma, Spain. The time series spans approximately 70 minutes with a field of view of 29" × 29" ne…
A Wide Field Planetary Camera 2 Study of the Resolved Stellar Population of the Pegasus Dwarf Irregular Galaxy (DDO 216)
Saha, A.; Mateo, M.; Gallagher, J. S. +5 more
The stellar population of the Pegasus dwarf irregular galaxy is investigated in images taken in the F439W (B), F555W (V), and F814W (I) bands with the Wide Field Planetary Camera 2 (WFPC2) on the Hubble Space Telescope. With WFPC2 the Pegasus dwarf is highly resolved into individual stars to limiting magnitudes of about 25.5 in B and V and 25 in I…
IRAS 23385+6053: A Prototype Massive Class 0 Object
Testi, Leonardo; Molinari, Sergio; Brand, Jan +2 more
IRAS 23385+6053 is a young stellar object with a luminosity of ~1.6×104 Lsolar at a kinematic distance of 4.9 kpc. This candidate precursor of an ultracompact H II region is associated with a millimeter source detected at the James Clerk Maxwell Telescope but is undetected at centimeter wavelengths with the VLA. We observed t…
The art of fitting p-mode spectra. I. Maximum likelihood estimation
Appourchaux, T.; Gizon, L.; Rabello-Soares, M. -C.
In this article we present our state of the art of fitting helioseismic p-mode spectra. We give a step by step recipe for fitting the spectra: statistics of the spectra both for spatially unresolved and resolved data, the use of Maximum Likelihood estimates, the statistics of the p-mode parameters, the use of Monte-Carlo simulation and the signifi…
Dust Emission and Molecular Depletion in L1498
Langer, W. D.; Velusamy, T.; Willacy, K.
We present 100 and 200 µm ISOPHOT observations of the dense core L1498. We have mapped the central core by using ΔI200=I200-I100/Θ, where ΔI200 is a measure of the emission from the cold dust and Θ=I100/I200 in the outer regions. The dust continuum emission provides informatio…
Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XIII. Ultraviolet Observations of the Broad-Line Radio Galaxy 3C 390.3
Shull, J. M.; Malkan, M. A.; Martin, P. G. +44 more
As part of an extensive multiwavelength monitoring campaign, the International Ultraviolet Explorer satellite was used to observe the broad-line radio galaxy 3C 390.3 during the period 1994 December 31-1996 March 5. Spectra were obtained every 6-10 days. The UV continuum varied by a factor of 7 through the campaign, while the broad emission lines …
Deep Hubble Space Telescope Observations of Star Clusters in NGC 1275
Ballester, Gilda E.; Crisp, David; Grillmair, Carl J. +15 more
We present an analysis of compact star clusters in deep Hubble Space Telescope Wide Field Planetary Camera 2 images of NGC 1275. B- and R-band photometry of roughly 3000 clusters shows a bimodality in the B - R colors, suggesting that distinct old and young cluster populations are present. The small spread in the colors of the blue clusters is con…
HST Planetary Camera images of quasar host galaxies
Boksenberg, A.; Macchetto, F. D.; Crane, P. +6 more
We present Hubble Space Telescope (HST) images of seven low-redshift quasars (six taken with the Planetary Camera, one with the Wide Field Camera). These complete the sample of 14 quasars observed by the Faint Object Camera Investigation Definition Team (FOC IDT). Following subtraction of the quasar nuclear light, host galaxies can be seen in all …
ISO-SWS observations of infrared absorption bands of the diffuse interstellar medium: The 6.2 MU M feature of aromatic compounds
de Graauw, Th.; Morris, P. W.; van Dishoeck, E. F. +8 more
We present ISO-SWS spectroscopy of eight strong infrared sources with large extinction through the diffuse interstellar medium. These are five late-type Wolf-Rayet stars, the blue hypergiant Cyg OB2 #12 and the Galactic Center Sources 3 and 4. The spectra show a number of absorption features that can be ascribed to interstellar dust and gas. Featu…