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A Z = 5.34 Galaxy Pair in the Hubble Deep Field
Dey, Arjun; Bunker, Andrew; Spinrad, Hyron +5 more
We present spectrograms of the faint V-drop (V_606 = 28.1, I_814 = 25.6) galaxy pair HDF 3-951.1 and HDF 3-951.2 obtained at the Keck II Telescope. In a recent study, Fernández-Soto, Lanzetta, & Yahil derive a photometric redshift of z_ph=5.28^+0.34_-0.41 (2 sigma) for these galaxies; our integrated spectrograms show a large and abrupt discont…
Hubble Space Telescope Wide Field Planetary Camera 2 Observations of eta Carinae
Frank, Adam; Davidson, Kris; Bally, John +3 more
Hubble Space Telescope (HST) continuum and emission-line images of eta Carinae obtained with the Planetary Camera (PC) of the Wide Field Planetary Camera 2 show a startling wealth of detailed structure in the expanding Homunculus Nebula and outer debris field. Using a combination of dithering and image deconvolutions, we have achieved a resolution…
The AC 2000: The Astrographic Catalogue on the System Defined by the HIPPARCOS Catalogue
Urban, S. E.; Wycoff, G. L.; Martin, J. C. +4 more
The AC 2000 is a positional catalog of 4,621,836 stars covering the entire sky. The average epoch of position is 1907. The data are from the images measured and published as part of the Astrographic Catalogue (AC). The positions are on the system defined by the Hipparcos Catalogue, having originally been reduced plate-by-plate using the Astrograph…
The Metallicity and Dust Content of HVC 287.5+22.5+240: Evidence for a Magellanic Clouds Origin
Sembach, Kenneth R.; Savage, Blair D.; Wakker, Bart P. +3 more
We estimate the abundances of S and Fe in the high-velocity cloud HVC 287.5+22.5+240, which has a velocity of 240 km s^-1 with respect to the local standard of rest and Galactic direction l ~ 287 deg and b ~ 23 deg. The measurements are based on UV absorption lines of these elements in the Hubble Space Telescope spectrum of NGC 3783, a background …
A Blind Test of Photometric Redshift Prediction
Dickinson, Mark; Sawicki, Marcin; Hogg, David W. +16 more
Results of a blind test of photometric redshift predictions against spectroscopic galaxy redshifts obtained in the Hubble Deep Field with the Keck Telescope are presented. The best photometric redshift schemes predict spectroscopic redshifts with a redshift accuracy of Deltaz < 0.1 for more than 68% of sources and with Deltaz < 0.3 for 100%,…
Radii and Effective Temperatures for K and M Giants and Supergiants. II.
van Belle, G. T.; Thompson, R. R.; Dyck, H. M.
We present new interferometric observations for 74 luminous red stars, made in the near-infrared. We show that our 2.2 µm uniform-disk diameters agree with other near-infrared diameter determinations (lunar occultations and interferometers) for 22 stars measured in common with ours. From our new data, we derive effective temperatures that ar…
The Recent Star Formation History of GR 8 from Hubble Space Telescope Photometry of the Resolved Stars
Saha, A.; Gallagher, J.; Mateo, Mario +6 more
We have used the Hubble Space Telescope to observe the resolved stars in the dwarf irregular galaxy GR 8 (DDO 155, UGC 8091). The data consisted of dithered Wide Field Planetary Camera 2 images in three bands: F439W (1 hr), F555W (30 minutes), and F814W (30 minutes). The stellar photometry was extracted with a modified version of DoPHOT. Artificia…
Weak and Post-T Tauri Stars around B-Type Members of the Scorpius-Centaurus OB Association
Martín, E. L.
I report medium-resolution (FWHM = 1.9 Å) spectroscopic observations of six Hα emission-line stars proposed in 1993 by Meyer, Wilking, & Zinnecker to be T Tauri stars formed in the vicinity of the B1 giant sigma Sco, a bright member of the Sco-Cen OB association. Using spectroscopic criteria (spectral types, Hα and Li i equivalent widths), whi…
Dwarf Elliptical Galaxies in the M81 Group: The Structure and Stellar Populations of BK5N and F8D1
Da Costa, G. S.; Caldwell, Nelson; Seitzer, Patrick +1 more
The M81 Group is one of the nearest groups of galaxies, but its properties are quite different from those of the Local Group. It has therefore provided a different environment for the evolution of its member galaxies. We have carried out a CCD survey of the M81 Group to search for analogs to Local Group dwarf elliptical (dE) galaxies. All the M81 …
The Radio Properties of NGC 5253 and Its Unusual H II Regions
Turner, Jean L.; Beck, Sara C.; Ho, Paul T. P.
We present VLA images of the radio continuum emission of the starburst in NGC 5253 at wavelengths of 6, 3.6, and 2 cm, with resolutions of 1"-2", and at 20 cm with resolution of ~9". A spectral index map constructed from the 6 and 2 cm images indicates that thermal free-free emission from ionized gas, most of it from a single source, dominates the…