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The Star Cluster System of the Merger Remnant NGC 7252
Whitmore, Bradley C.; Fall, S. Michael; Miller, Bryan W. +1 more
We present new U, B, V, and I images of the prototypical merger remnant NGC 7252 obtained with the WFPC2 instrument of the Hubble Space Telescope. The photometry reaches about 3 mag deeper than the previous observations with WF/PC1 and we detect 499 cluster candidates, most of them previously undiscovered. We can distinguish three populations of s…
Spiral Galaxies with WFPC2.I.Nuclear Morphology, Bulges, Star Clusters, and Surface Brightness Profiles
Carollo, C. M.; Stiavelli, M.; de Zeeuw, P. T. +1 more
We report the analysis of HST WFPC2 F606W images of a sample of 35 spiral galaxies. We describe the optical morphological properties of the galaxies on scales of a few tens of parsecs, derive the surface brightness profiles for 18 of them, and present the results of analytical fits to these profiles. We find that: (I) Several galaxies, despite the…
Dust and Recent Star Formation in the Core of NGC 5253
Meurer, Gerhardt R.; Calzetti, Daniela; Leitherer, Claus +4 more
Ultraviolet and optical narrow and broad band images of NGC 5253 obtained with the Hubble Space Telescope Wide Field and Planetary Camera 2 are used to derive the properties of the dust distribution and the recent star formation history of this metal-poor dwarf galaxy. Corrections for the effects of dust are important in the center of NGC 5253: du…
The Dwarf Irregular Galaxy Sextans A. II. Recent Star Formation History
Skillman, Evan D.; Saha, A.; Gallagher, J. +6 more
We have used the Hubble Space Telescope to obtain photometric data of the resolved stars in the nearby (D = 1.4 Mpc) dwarf irregular galaxy Sextans A (DDO 75, A 1008-04). The data consist of WFPC2 images in 3 bands: F439W (1 hour), F555W (30 minutes), and F814W (30 minutes). We constructed very accurate color-magnitude diagrams (CMDs) in V and I d…
Extraplanar Dust in the Edge-On Spiral NGC 891
Savage, Blair D.; Howk, J. Christopher
We present high-resolution (0.6"-0.65") optical broad-band images of the edge-on Sb galaxy NGC 891 obtained with the WIYN 3.5-m telescope. These BVR images reveal a complex network of hundreds of dust absorbing structures far from the mid-plane of the galaxy. The dust structures have a wide range of morphologies and are clearly visible to [ζ]≤1.5 …
The Evolution of the Final Helium Shell Flash Star V605 Aquilae From 1917 to 1997
De Marco, Orsola; Clayton, Geoffrey C.
Only three stars have been observed going through a final helium shell flash since the advent of modem instrumentation, FG Sagittae (in 1894), V605 Aquilae (in 1919), and Sakurai's Object (in 1996). In this paper, we present for the first time a spectrum taken of V605 Aql, while it was in its cool giant phase in 1921. This spectrum is identical to…
Absorption by Highly Ionized Interstellar Gas Along Extragalactic and Galactic Sight Lines
Sembach, Kenneth R.; Savage, Blair D.; Lu, Limin
We present intermediate resolution (FWHM ∼10-20 km s-1) Goddard High Resolution Spectrograph observations of Galactic C IV and N V absorption along the sight lines to Fairall 9, Mrk 509, PKS 2155-304, and NGC 5548. These observations also provide measures of Si II and S II along the sight lines. Recent measurements of Si IV absorption f…
Planetary Nebulae in the Globular Cluster PAL 6 and NGC 6441
Henry, R. B. C.; Kwitter, K. B.; Morse, Jon A. +2 more
Jacoby & Fullton (1998, in preparation) recently surveyed the Galactic globular cluster system for planetary nebulae and identified excellent candidates in the disk clusters Pal 6 and NGC 6441. Velocities, abundances, and central star properties for these two nebulae are derived. There is a 0.5% probability that the nebula in Pal 6 is a chance…
Hubble Space Telescope Images of the HH 111 Jet.
Hartigan, Patrick; Bally, John; Reipurth, Bo +2 more
We have observed the classic Herbig-Haro jet HH 111 with the Wide Field and Planetary Camera 2 aboard the Hubble Space Telescope (\HST) through narrow-band filters isolating Hα and [S II]lambda lambda6716 ,6731 emission. The new images fully resolve the body of the jet into a series of small bow shocks, which we conclude form as fast jet material …
Resolving the Helium Lyman-alpha Forest: Mapping Intergalactic Gas and Ionizing Radiation at z~3
Anderson, Scott F.; Hogan, Craig J.; Rugers, Martin H.
We present a new, high resolution HST/GHRS spectrum of quasar Q0302-003, and use the He(+) Lyman-alpha absorption, together with a high resolution Keck spectrum of the HI Lyman-alpha forest, to probe the distribution and ionization state of foreground gas just below the quasar redshift z~ 3.3. Within ~ 4000 km/sec of the quasar redshift the spectr…