Search Publications
Temporal Variations of the Solar Rotation Rate at High Latitudes
Basu, Sarbani; Antia, H. M.
Frequency splitting coefficients from Global Oscillation Network Group and Michelson Doppler Imager observations covering the period 1995-2001 are used to study temporal variations in the solar rotation rate at high latitudes. The torsional oscillation pattern in the Sun is known to penetrate to a depth of about 0.1 Rsolar with alternat…
Physical Parameters of Erupting Luminous Blue Variables: NGC 2363-V1 Caught in the Act
Drissen, Laurent; Robert, Carmelle; Smith, Linda J. +3 more
A quantitative study of the luminous blue variable NGC 2363-V1 in the Magellanic galaxy NGC 2366 (D=3.44 Mpc) is presented, based on ultraviolet and optical Hubble Space Telescope STIS spectroscopy. Contemporary WFPC2 and William Herschel Telescope imaging reveals a modest V-band brightness increase of ~0.2 mag per year between 1996 January-1997 N…
Locating the Starburst in the SCUBA Galaxy SMM J14011+0252
Kneib, J. -P.; Ivison, R. J.; Frayer, D. T. +2 more
We present new, multiwavelength, high-resolution imaging of the luminous, submillimeter galaxy SMM J14011+0252, an interacting starburst at z=2.56. Our observations comprise optical imaging from the Hubble Space Telescope, sensitive radio mapping from the Very Large Array, and CO observations from the Owens Valley Radio Observatory and Berkeley-Il…
Absorption and Reddening in the Seyfert Galaxy NGC 3227
Kraemer, S. B.; Crenshaw, D. M.; Bruhweiler, F. C. +1 more
We have obtained low-dispersion spectra of NGC 3227 with the Space Telescope Imaging Spectrograph (STIS) to study the intrinsic UV absorption and the reddening of the nucleus in this Seyfert 1 galaxy. The UV spectra show a wealth of absorption lines at the systemic redshift that span a wide range in ionization state (Mg I to N V). The equivalent w…
A Possible Massive Asteroid Belt around ζ Leporis
Jura, M.; Chen, C. H.
We have used the Keck I telescope to image at 11.7 and 17.9 µm the dust emission around ζ Leporis, a main-sequence A-type star at 21.5 pc from the Sun with an infrared excess. The excess is at most marginally resolved at 17.9 µm. The dust distance from the star is probably <=6 AU, although some dust may extend to 9 AU. The mass of o…
Structure and Mass of a Young Globular Cluster in NGC 6946
Brodie, Jean P.; Elmegreen, Bruce G.; Hodge, Paul W. +3 more
Using the Wide Field Planetary Camera 2 on board the Hubble Space Telescope, we have imaged a luminous young star cluster in the nearby spiral galaxy NGC 6946. Within a radius of 65 pc, the cluster has an absolute visual magnitude, MV=-13.2, comparable to the most luminous young ``super star clusters'' in the Antennae merger galaxy. UBV…
Hubble Space Telescope Optical-Near-Infrared Colors of Nearby R1/4 and Exponential Bulges
Stiavelli, Massimo; de Zeeuw, P. Tim; Carollo, C. Marcella +2 more
We have analyzed V, H, and J Hubble Space Telescope (HST) images for a sample of early- to late-type spiral galaxies and have reported elsewhere the statistical frequency of R1/4-law and exponential bulges in our sample as a function of Hubble type and the frequency of occurrence and structural properties of the resolved central nuclei …
Unusual Depletions toward the SMC Star SK 155-Differences in Dust Composition in the SMC Interstellar Medium?
York, Donald G.; Blades, J. Chris; Welty, Daniel E. +2 more
We report initial results from an analysis of Hubble Space Telescope/Space Telescope Imaging Spectrograph echelle spectra of interstellar absorption toward Sk 155, located in the ``wing'' region of the SMC. There are at least 12 Milky Way (disk and halo) and at least 25 SMC components discernible in the profiles of various neutral and singly ioniz…
Structure of Protostellar Collapse Candidate B335 Derived from Near-Infrared Extinction Maps
Wilner, David J.; Myers, Philip C.; Lada, Charles J. +3 more
We present a near-infrared extinction study of the dark globule B335, a protostellar collapse candidate, using data from the Hubble Space Telescope/Near Infrared Camera and Multi-Object Spectrometer and the W. M. Keck Observatory. These data allow a new quantitative test of the ``inside-out'' collapse model previously proposed to explain molecular…
Evidence of a Supermassive Black Hole in the Galaxy NGC 1023 from the Nuclear Stellar Dynamics
Nelson, C.; Bender, R.; Green, R. F. +13 more
We analyze the nuclear stellar dynamics of the SB0 galaxy NGC 1023, utilizing observational data both from the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope and from the ground. The stellar kinematics measured from these long-slit spectra show rapid rotation (V~70 km s-1 at a distance of 0.1"=4.9 pc from the nuc…