Search Publications
Cepheid Calibration of the Peak Brightness of Type IA Supernovae: Calibration of SN 1990N in NGC 4639 Averaged with Six Earlier Type IA Supernova Calibrations to Give H 0 Directly
Panagia, N.; Saha, A.; Labhardt, Lukas +3 more
Periods and light curves have been measured with the Hubble Space Telescope for 20 Cepheids in NGC 4639, parent galaxy to the Type Ia, prototypical supernova SN 1990N. The periods range from 17 to 69 days. The mean apparent magnitudes, averaged over the light curves, range from <V> = 25.6 to <V> = 27.3. Well-determined period-luminosit…
First Image of the Surface of a Star with the Hubble Space Telescope
Dupree, A. K.; Gilliland, Ronald L.
A direct image of the surface of a star, Betelgeuse (= alpha Ori; M2 Iab), has been obtained with the Faint Object Camera on the Hubble Space Telescope. Images in two ~300 A--wide bands centered at 2550 and 2800 A cover ~10 resolution elements on the stellar disk. The ultraviolet diameter of Betelgeuse of 125 +/- 5 mas at 2500 A (corresponding to …
Hubble Space Telescope Ultraviolet Imaging and Spectroscopy of the Bright Starburst in the Wolf-Rayet Galaxy NGC 4214
Robert, Carmelle; Filippenko, Alexei V.; Leitherer, Claus +3 more
We have obtained an HST Faint Object Camera ultraviolet image and Faint Object Spectrograph ultraviolet spectra of the central starburst region in the nearby amorphous galaxy NGC 4214. The ultraviolet image reveals a bright, compact, starburst knot surrounded by more than 200 fainter pointlike sources. Spectral synthesis modeling of the ultraviole…
The Hubble Space Telescope Quasar Absorption Line Key Project. VII. Absorption Systems at Z abs <= 1.3
Turnshek, David A.; Schneider, Donald P.; Savage, Blair D. +9 more
We present evidence that clumps of Lyα lines are physically associated with about half of the extensive metal-line systems (absorption systems with four or more observed metal-line species) found in this paper, demonstrate that all four Lyman-limit systems discussed here correspond to extensive metal-line absorption systems, and present an extraor…
Parallax Observations with the Hubble Space Telescope Yield the Distance to Geminga
Caraveo, Patrizia A.; Bignami, Giovanni F.; Mignani, Roberto +1 more
Using data from Hubble Space Telescope observations, we report the first optical measurement of the annual parallax of a neutron star. This is the counterpart of the X-ray/ gamma -ray pulsar Geminga, for which strong proper motion has already been reported. Significant displacement from such motion is detected using WFPC2 observations, taken at th…
Cepheid Calibration of the Peak Brightness of SNe Ia. V. SN 1981B in NGC 4536
Panagia, N.; Saha, A.; Labhardt, Lukas +3 more
Observations have been made with the Hubble Space Telescope between 1994 June and August over a 67 day interval, comprising 17 epochs in the F555W band and 5 epochs in the F814W band. The target was a region of an outlying spiral arm of NGC 4536 [Sbc(s)I-II), a galaxy that was parent to the type Ia supernova SN 1981B. Seventy-three Cepheids were f…
The Gas and Dust Abundances of Diffuse Halo Clouds in the Milky Way
Sembach, Kenneth R.; Savage, Blair D.
We present Goddard High-Resolution Spectrograph observations of the interstellar Mg II, Si II, P II, S II, Mn II, Cr II, Fe II, Ni II, Zn II, and Ge II lines toward HD 116852, a star at -1.3 kpc from the Galactic plane and a distance of 4.8 kpc in the direction l = 304°.9, b = -16°.1. The intermediate-resolution (FWHM ≈ 11-18 km s-1) ob…
New Insights into the Physical Nature of LINERs from a Multiwavelength Analysis of the Nucleus of M81
Filippenko, Alexei V.; Ho, Luis C.; Sargent, Wallace L. W.
We discuss the physical conditions and excitation of the nucleus of M81 by combining ground-based optical spectra, archival Hubble Space Telescope (HST) Ultraviolet (UV) and optical spectral, and published X- ray measurements. This well known low-ionization nuclear emission-line region (LINER) is representative of a general class of objects though…
A Comparison between the Narrow-Line Regions of Seyfert 1 and Seyfert 2 Galaxies
Kinney, Anne L.; Schmitt, Henrique R.
We present high-resolution narrow-band [O III] images of Seyfert 1 and Seyfert 2 galaxies, obtained in the Hubble Space Telescope Data Archive. The continuum-subtracted [O III] images were used to measure the narrow- line region (NLR) sizes and compare them with the predictions from the Unified Scheme. This paper shows that the Seyfert 1 NLR sizes…
Hubble Space Telescope Spectroscopic Evidence for a 2 10 9 Msun Black Hole in NGC 3115
Gebhardt, Karl; Richstone, Douglas; Kormendy, John +7 more
The discovery by Kormendy & Richstone of an M• ~= 109 M⊙ massive dark object (MDO) in NGC 3115 is confirmed with higher resolution spectroscopy from the Canada-France-Hawaii Telescope (CFHT) and the Hubble Space Telescope (HST). Measurements with the CFHT and Subarcsecond Imaging Spectrograph improve the resolution from sigma * = 0."44 to sigm…