Search Publications
Hubble Space Telescope Imaging Polarimetry of eta Carinae
Hillier, D. J.; Nota, A.; Clampin, M. +3 more
Linear polarization measurements have been a key to our understanding of the massive star system eta Carinae and its surrounding Homunculus nebula. We here present the results of (linear) polarimetric imaging of eta Carinae in the V band (F555W) with the Hubble Space Telescope's Wide Field Planetary Camera 2 (HST/WFPC2). The data agree well with p…
Near-Infrared Observations of Hot Spots in the Circumnuclear Rings of NGC 2997 and NGC 6951
Elmegreen, Debra Meloy; Chromey, Frederick R.; Sawyer, Jessica E. +1 more
Near-infrared observations of NGC 2997 and NGC 6951 reveal complete rings of symmetrically placed hot spots, which are star-forming complexes. The masses of the complexes range from a few times 10^4 to a few times 10^5 M_solar in both galaxies. The regular hot-spot spacings of about 200 pc in a ring 55 pc thick in NGC 2997 and 380 pc in a ring 150…
Deep Hubble Space Telescope Observations of Blue Star Clusters in NGC 3597
Ballester, Gilda E.; Crisp, David; Grillmair, Carl J. +15 more
We have analyzed HST/WFPC2 images of NGC 3597 and find ~700 compact objects surrounding the galaxy with an average (B-R)_0~0.6. We propose that the majority of these objects are young globular clusters. They have a spread in colors that is consistent with that expected for a population of young clusters with a common age and spread induced by phot…
The Integrated Spectra of M32 and of 47 Tucanae: A Comparative Study in the Mid-Ultraviolet With IUE
Rose, James A.; Deng, Shibing
Low-resolution mid-UV spectra of M32 and 47 Tuc have been extracted from the IUE archival database, along with spectra of 41 F and G dwarfs with well-determined atmospheric parameters and integrated spectra of 24 Galactic globular clusters. We have used five mid-UV spectral indices defined by Fanelli et al. to constrain the stellar content of M32 …
ISOCAM 15 Micron Search for Distant Infrared Galaxies Lensed by Clusters
Helou, George; Antonucci, Robert; Barvainis, Richard
In a search for lensed infrared galaxies, ISOCAM images have been obtained toward the rich clusters Abell 2218 and Abell 2219 at 15 mum. Nine galaxies (four in Abell 2218 and five in Abell 2219) were detected with flux levels in the range 530-1100 muJy. Three of the galaxies detected in Abell 2218 have previously known redshifts; of these one is a…
The Fall and Rise of V854 Centauri: Long-Term Ultraviolet Spectroscopy of a Highly Active R Coronae Borealis Star
Marang, Fred; Clayton, Geoffrey C.; Lawson, Warrick A. +6 more
We examine long-term low-dispersion International Ultraviolet Explorer SWP and LWP spectroscopy of the R Coronae Borealis (RCB) star V854 Cen, obtained across the deep (DeltaV>6 mag) 1991, 1992-1993, and 1994 declines. We also report the optical light curve for the star in the interval 1987-1998, including multicolor photometry obtained during …
The Central Regions of M81
Davidge, T. J.; Courteau, S.
High-angular resolution near-infrared images obtained with the Canada-France-Hawaii Telescope adaptive optics system are combined with archival Hubble Space Telescope data to investigate the central regions of the nearby Sb galaxy M81 (NGC 3031). The spectral-energy distribution of the circumnuclear region, which extends out to 1.5" (~24 pc if mu_…
300-580 Nanometer Long-Slit Spectroscopy of Comet Tabur (C/1996 Q1)
Smith, Graeme H.; Turner, Neal J.
Comets Liller (C/1988 A1) and Tabur (C/1996 Q1) have similar orbits and are thought to have been a single comet until they split at a previous perihelion passage. Long-slit spectra of comet Tabur were obtained on consecutive nights around 45 days before perihelion. Nuclear production rate ratios for NH/CN, C3/CN, and C2/CN, d…
The Second Cape Photographic Catalogue on the HIPPARCOS System
Zacharias, N.; Zacharias, M. I.; de Vegt, C.
The Second Cape Photographic Catalogue (CPC2) is an astrometric, photographic catalog covering the entire Southern Hemisphere to a limiting magnitude of about 10.5. The Hipparcos Catalogue has been used for a new, plate-by-plate, rigorous reduction. A significant improvement over the release 1 version of the data was achieved. With an average accu…
UGC 3995: A Close Pair of Spiral Galaxies
Marziani, P.; D'Onofrio, M.; Sulentic, J. W. +1 more
UGC 3995 is a close pair of spiral galaxies whose eastern component hosts a Seyfert 2 nucleus. The object was selected for observation because a bright filamentary structure that apparently connects the nuclei of the two galaxies made it a good candidate to investigate a possible connection between galaxy interactions and active galactic nuclei. W…