Search Publications
A Strong Jet-Cloud Interaction in the Seyfert Galaxy IC 5063: VLBI Observations
Tsvetanov, Z.; Morganti, R.; Oosterloo, T. A. +4 more
We present 21 cm H I line and 13 cm continuum observations, obtained with the Australian Long Baseline Array, of the Seyfert 2 galaxy IC 5063. This object appears to be one of the best examples of Seyfert galaxies where shocks produced by the radio plasma jet influence both the radio and the near-infrared emission. The picture resulting from the n…
The Morphology of the Emission-Line Region Of Compact Steep-Spectrum Radio Sources
Capetti, A.; Morganti, R.; Axon, D. J. +3 more
We present the results of HST narrowband imaging of 11 compact steep-spectrum (CSS) radio sources. Five of them (3C 48, 3C 147, 3C303.1, 3C 277.1, and 4C 12.50) were observed as part of a dedicated ``pointed'' program of deep line imaging, at the redshifted wavelength of the [O III] λ5007 emission line. For six additional sources (3C 49, 3C 93.1, …
The Halo Stars in NGC 5128. II. An Outer Halo Field and a New Metallicity Distribution
Harris, William E.; Harris, Gretchen L. H.
We present new Hubble Space Telescope WFPC2 (V, I) photometry for stars in NGC 5128 at a projected distance more than 30 kpc from the galaxy center. The color-magnitude diagram shows an old red-giant branch which is extremely broad in color, identical in its characteristics with our previously observed 20 kpc halo field (Harris et al.). To derive …
UBVRI and Hα Photometry of the Young Open Cluster NGC 6530
Bessell, Michael S.; Sung, Hwankyung; Chun, Moo-Young
New UBVRI and Hα photometry has been obtained for the young open cluster NGC 6530 located 10' east of the Lagoon Nebula (M8). We found 37 pre-main-sequence (PMS) stars with Hα emission and nine PMS candidates using the R-Hα color, a measure of Hα emission. From this new photometry we derived the cluster parameters (V0-MV=11.2…
Star Formation in Galaxies between Redshifts of 0.7 and 1.8
Hopkins, A. M.; Connolly, A. J.; Szalay, A. S.
We present an analysis of the star formation rate in galaxies with redshifts in the range 0.7<z<1.8 using Near Infrared Camera and Multi-Object Spectrograph (NICMOS) grism spectral observations. We detect 163 galaxies in an area of ~4.4 arcmin2, 37 of which show possible Hα emission. We extend the observed Hα luminosity function (…
ISO Mid-Infrared Observations of Normal Star-Forming Galaxies: The Key Project Sample
Beichman, Charles A.; Dale, Daniel A.; Dinerstein, Harriet L. +17 more
We present mid-infrared maps and preliminary analysis for 61 galaxies observed with the ISOCAM instrument aboard the Infrared Space Observatory. Many of the general features of galaxies observed at optical wavelengths-spiral arms, disks, rings, and bright knots of emission-are also seen in the mid-infrared, except the prominent optical bulges are …
Metal Abundances in the Magellanic Stream
Shull, J. Michael; Stocke, John T.; Gibson, Brad K. +3 more
We report on the first metallicity determination for gas in the Magellanic Stream, using archival Hubble Space Telescope (HST) GHRS data for the background targets Fairall 9, III Zw 2, and NGC 7469. For Fairall 9, using two subsequent HST revisits and new Parkes multibeam narrowband observations, we have unequivocally detected the MS I H I compone…
Radial Velocity Studies of Close Binary Stars. III
Rucinski, Slavek M.; Lu, Wenxian; Mochnacki, Stefan W.
Radial velocity measurements and simple sine-curve fits to the orbital velocity variations are presented for the third set of 10 close binary systems: CN And, HV Aqr, AO Cam, YY CrB, FU Dra, RZ Dra, UX Eri, RT LMi, V753 Mon, and OU Ser. All systems except two (CN And and RZ Dra) are contact, double-line spectroscopic binaries, with four of them (Y…
High Angular Resolution Determination of Extinction in the Orion Nebula
O'Dell, C. R.; Yusef-Zadeh, F.
The optical appearance of the Orion Nebula is significantly altered by the presence of interstellar extinction. Since Orion is high above the Galactic plane and is nearby, most of this extinction is due to material immediately in front of the associated star cluster. This extinction fundamentally alters the optical appearance of the Orion Nebula. …
The DIRECT Project: Influence of Blending on the Cepheid Distance Scale. I. Cepheids in M31
Stanek, K. Z.; Macri, L. M.; Mochejska, B. J. +1 more
We investigate the influence of blending on the Cepheid distance scale. Blending is the close association of a Cepheid with one or more intrinsically luminous stars. High-resolution HST images are compared with our ground-based data, obtained as part of the DIRECT project, for a sample of 22 Cepheids in the M31 galaxy. The average (median) V-band …