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NGC 3603 and Its Wolf-Rayet Stars: Galactic Clone of R136 at the Core of 30 Doradus, but without the Massive Surrounding Cluster Halo
Drissen, Laurent; Moffat, Anthony F. J.; Shara, Michael M.
HST/PC images of the dense stellar cluster at the center of the Galaxy's most massive visible H II region, NGC 3603, reveal remarkable similarity to the dense core R136 in the Local Group's most massive Giant H II region, 30 Dor. The projected star density for stars brighter than M_V_ = -5.0 in both objects increases inwards to the last data bin i…
UBV Stellar Photometry of the 30 Doradus Region of the Large Magellanic Cloud With the Hubble Space Telescope
Heap, Sara R.; Malumuth, Eliot M.
We report on Planetary Camera observations of the central region of 30 Doradus in the Large Magellanic Cloud. These images of 30 Doradus are the first "deep" HST exposures that have appropriate photometric calibration. The B band (F439W) image, which shows RI 36a at the center of the PC6 CCD chip, reveals over 200 stars within 3" of the center of …
Simultaneous observations of Seyfert 1 galaxies with IUE, ROSAT and GINGA
Walter, R.; Wamsteker, W.; Courvoisier, T. J. -L. +4 more
Simultaneous observations of 8 Seyfert 1 type active galactic nuclei (Fairall-9, Mrk 590, NGC 4051, 3C 273, NGC 5548, Mrk 841, Q1821+643 and 3C 390.3) obtained with IUE, ROSAT and, for 5 targets, with Ginga are presented and analysed with the aim to describe the ultraviolet to soft X-ray spectral component in these sources. The unobservable far ul…
The Ultraviolet Pulsations of the Cataclysmic Variable AE Aquarii as Observed with the Hubble Space Telescope
Eracleous, Michael; Horne, Keith; Wood, Janet H. +3 more
We present the results of high time resolution UV spectroscopy and simultaneous high-speed UBVR photometry of AE Aqr. The UV spectra were obtained with the Faint Object Spectrograph aboard the Hubble Space Telescope (HST), and the photometry was carried out with the 82 sec telescope at McDonald Observatory. Our study focuses on the coherent 33 sce…
The Hubble Space Telescope Medium Deep Survey with the Wide Field and Planetary Camera. I. Methodology and Results on the Field near 3C 273
Im, M.; Glazebrook, K.; Illingworth, G. D. +21 more
We present results from the Medium Deep Survey (MDS), a Key Project using the Hubble Space Telescope. Wide Field Camera images of random fields have been taken in "parallel mode" with an effective resolution of 0'2 FWHM in the V(F555W) and I(F785LP) filters. The exposures presented here were targeted on a field 6' away from 3C 273, and resulted in…
Element abundances of classical novae.
Starrfield, S.; Drechsel, H.; Andrea, J.
Physical conditions and element abundances in the optically thin shells of 11 classical novae with outbursts between 1978 and 1989 were determined from an analysis of UV and optical spectra obtained during the nebular stage. Eight novae were studied on the basis of new optical and UV spectra: PW Vul (1984), QU Vul (1984), V842 Cen (1986), V827 Her…
Imaging of Two Damped Lyman Alpha Absorbers at Intermediate Redshifts
Dickinson, Mark; Pettini, Max; Steidel, Charles C. +1 more
By observing the fields of the QSOs 3C 286 and PKS 1229-021 in the I and K_s_ bands under good seeing conditions, we have resolved faint galaxy images close to the QSO sight lines. The sizes, magnitudes, and colors of these objects suggest that they are the galaxies producing 21 cm absorption at z_abs_ = 0.6922 and 0.3950 in the spectra of 3C 286 …
An X-Ray and Optical Study of the Supernova Remnant W44
Rho, Jeonghee; Hester, J. Jeff; Schlegel, Eric M. +1 more
We report the results of a 8000 s observation of the supernova remnant W44 using the ROSAT Position Sensitive Proportional Counter (PSPC). The image shows the same centrally peaked morphology observed by the Einstein IPC and contrasts with the shell-like radio morphology. The eastern limb shows a lack of X-ray emission within the radio shell, prob…
Galaxy Pairs in Deep HST Images: Evidence for Evolution in the Galaxy Merger Rate
Keel, William C.; Windhorst, Rogier A.; Burkey, Jordan M. +1 more
We use four deep serendipitous fields observed with the HST Wide-Field Camera to constrain the rate of galaxy merging between the current epoch and z~0.7. Since most mergers occur between members of bound pairs, the merger rate is given to a good approximation by (half) the rate of disappearance of galaxies in pairs. An objective criterion for pai…
A forward-reverse shock pair in the solar wind driven by over-expansion of a coronal mass ejection: Ulysses observations
Balogh, A.; McComas, D. J.; Goldstein, B. E. +5 more
A previously unidentified type of solar wind forward-reverse shock pair has been observed by Ulysses at 4.64 AU and S32.5°. In contrast to most solar wind forward-reverse shock pairs, which are driven by the speed difference between fast solar wind plasma and slower plasma ahead, this particular shock pair was driven purely by the over-expansion o…