Search Publications
What powers luminous infrared galaxies?
Lutz, D.; Genzel, R.; Sturm, E. +8 more
Based on the initial data sets taken with the ISO short wavelength spectrometer (SWS) we present a first discussion of the source of luminosity of (ultra-)luminous infrared galaxies (ULIRGs). By comparison of observations of 2.5-45µm lines to classical starbursts and active galactic nuclei and by modelling of the line emission we show that t…
Astrometric Analysis of the Homunculus of eta Carinae With the Hubble Space Telescope
Currie, Douglas G.; Lynds, Roger; Groth, Edward J. +6 more
Images of η Carinae, obtained with the HST Wide Field/Planetary Camera in 1990 October (WFl), 1991 April (PC 1), and 1992 December (WF2) have been used to perform a detailed study of the proper motion of the homunculus of η Carinae. This analysis yields the plane-of-the-sky astrometric velocities which range from tens of kilometers per second to o…
The 6.0 and 6.8µm absorption features in the spectrum of NGC 7538: IRS9.
Prusti, T.; de Graauw, T.; van Dishoeck, E. F. +6 more
Short Wavelength Spectrometer observations of the 6.0 and 6.8µm absorption features towards the obscured young stellar object NGC 7538: IRS9 are presented and compared to the features of a number of species measured in the solid phase. It is found that while solid H_2_O provides the bulk of the 6µm band, additional absorption is requir…
Hubble Space Telescope Ultraviolet Spectroscopy of NGC 1741: A Nearby Template for Distant Energetic Starbursts
Leitherer, Claus; Vacca, William D.; Conti, Peter S.
We have obtained a Hubble Space Telescope ultraviolet image and spectrum of the nearby Wolf-Rayet galaxy NGC 1741. The spatial morphology from the Faint Object Camera image is dominated by two main starburst centers, each being about 100 times as luminous as 30 Doradus. Both starburst centers are composed of several intense knots of recent star fo…
Pulsation models of δ Scuti variables. I. The high-amplitude double-mode stars.
Christensen-Dalsgaard, J.; Petersen, J. O.
The relations between high-amplitude δ Scuti stars and the much more abundant low-amplitude δ Sct variables are not clear. Both groups have similar periods and seem to have almost the same basic physical properties, although their light-curve characteristics are very different. In the last few years much improved observational data have been publi…
Detection of the Tip of the Red Giant Branch in NGC 5128
Soria, Roberto; Casertano, Stefano; Ballester, Gilda E. +14 more
We present a color-magnitude diagram of more than 10,000 stars in the halo of the galaxy NGC 5128 (Centaurus A), based on WFPC2 images through V-band and I-band filters. The position of the red giant branch (RGB) stars is compared with the loci of the red giant branch in six well- studied globular clusters and in the dwarf elliptical galaxy NGC 18…
On the Nature of the Faint Compact Narrow Emission-Line Galaxies: The Half-Light Radius--Velocity Width Diagram
Illingworth, Garth D.; Bershady, Matthew A.; Faber, S. M. +4 more
We present new measurements of emission-line velocity widths for five faint compact narrow emission-line galaxies (CNELGs) with 20.5 <= B <= 21.5 and redshifts z ~ 0.19 to 0.35. The spectra were taken at the Keck telescope using the HIRES spectrograph with a resolution of 8 km s-1 (FWHM). Emission-line profiles are roughly Gaussian with velo…
On the Morphology of the HST Faint Galaxies
Giavalisco, Mauro; Livio, Mario; Bohlin, Ralph C. +2 more
Deep imaging with the Hubble Space Telescope (HST) has revealed a population of rapidly evolving galaxies, which account for < 50% of the total counts at I <~ 22.5, are well distinct from the passively evolving normal ellipticals and spirals, and have morphologies that elude the traditional Hubble classification scheme. This classification h…
Ellipticals with Kinematically Distinct Cores: WFPC2 Imaging of Globular Clusters
Franx, Marijn; Illingworth, Garth D.; Forbes, Duncan A. +1 more
New globular clusters may form in the merger of two galaxies. Perhaps the best examples of merger remnants are the set of ellipticals with kinematically distinct cores. Here we present Hubble Space Telescope (HST) Wide Field and Planetary Camera 2 (WFPC2) imaging of 14 kinematically distinct core ellipticals to examine their globular cluster syste…
The Hubble Space Telescope Key Project on the Extragalactic Distance Scale. VI. The Cepheids in NGC 925
Illingworth, Garth D.; Madore, Barry F.; Freedman, Wendy L. +18 more
We report the detection of Cepheid variable stars in the barred spiral galaxy NGC 925, using the Hubble Space Telescope (HST) Wide-Field and Planetary Camera 2 (WFPC2). Twelve V (F555W) and four I (F814W) epochs of cosmic-ray split observations were obtained. Eighty Cepheids were discovered, with periods from 6 to ~80 days. Light curves of the Cep…