Search Publications
The Discovery of Circumstellar Arcs around Two Bipolar Proto-planetary Nebulae
Kwok, Sun; Hrivnak, Bruce J.; Su, Kate Y. L.
Circumstellar arcs have been discovered using the Hubble Space Telescope in two proto-planetary nebulae (PPNs), IRAS 16594-4656, and IRAS 20028+3910. This raises to five the number of PPNs in which such arcs have been detected and suggests that they are not rare and may even be common features. All five of these PPNs display a bipolar morphology, …
The Nuclear Cusp Slopes of Dwarf Elliptical Galaxies
Ferguson, Henry C.; Mack, Jennifer; Stiavelli, Massimo +3 more
We derive the light profiles for a sample of 25 dwarf elliptical galaxies observed by us with Hubble Space Telescope's Wide Field and Planetary Camera 2 in F555W and F814W. These profiles are fitted with Nuker, R1/4, exponential, and Sersic laws and are also used to derive the nuclear cusp slopes γ. We discuss the correlation of nuclear…
Star Formation History in the Solar Vicinity
Bertelli, G.; Nasi, E.
The star formation history in the solar neighborhood is inferred by comparing a sample of field stars from the Hipparcos catalog with synthetic color-magnitude diagrams. We consider separately the main sequence and the red giant region of the H-R diagram. The criteria for our best solutions are based on the χ2 minimization of star distr…
Kinematics of the Narrow-Line Region in the Seyfert 2 Galaxy Markarian 3
Gull, T. R.; Kraemer, S. B.; Crenshaw, D. M. +5 more
We present measurements of radial velocities for the narrow-line region gas in the Seyfert 2 galaxy Mrk 3 out to ~1 kpc from the nucleus. The observations consist of two data sets, both using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope: (1) an [O III] slitless spectrum with the G430M grating of the inner 3" around …
Caltech Faint Galaxy Redshift Survey. XIII. Spectral Energy Distributions for Galaxies in the Region of the Hubble Deep Field North
Cohen, Judith G.
We introduce a new empirical function for modeling the spectral energy distributions (SEDs) of galaxies. We apply it to a sample of 590 galaxies in the region of the Hubble Deep Field (HDF) with z<1.5 using multicolor photometry with wide wavelength coverage combined with spectroscopic redshifts from our 93% complete R-selected redshift survey …
2 Micron Narrowband Adaptive Optics Imaging in the Arches Cluster
Schaerer, D.; Schmutz, W.; Heydari-Malayeri, M. +3 more
Canada-France-Hawaii-Telescope adaptive optics bonnette images through narrowband filters in the K band are presented for the Arches cluster. Continuum fluxes, line fluxes, and equivalent widths are derived from high angular resolution images, some nearly diffraction limited, for the well-known massive stars in the Arches cluster. Images were obta…
A Near-Infrared Stellar Census of Blue Compact Dwarf Galaxies: The Wolf-Rayet Galaxy I Zw 36
Greggio, Laura; Hopp, Ulrich; Schulte-Ladbeck, Regina E. +2 more
We report the results of near-IR imaging in J and H, of I Zw 36 (~Zsolar/14) with the Hubble Space Telescope. Whereas imaging with the pre-COSTAR Faint Object Camera (FOC) previously resolved hot and massive stars in the near-UV, the NICMOS data furnish a census of the cool, intermediate- and low-mass stars. There clearly was star forma…
The Interaction between the Interstellar Medium and Star Formation in the Dwarf Starburst Galaxy NGC 4214
Scoville, Nick; Walter, Fabian; Taylor, Christopher L. +2 more
We present the first interferometric study of the molecular gas in the metal-poor dwarf starburst galaxy NGC 4214. Our map of the 12CO (1-0) emission, obtained at the Owens Valley Radio Observatory's millimeter array, reveals an unexpected structural wealth. We detected three regions of molecular emission in the northwest, southeast, an…
Interstellar Bubbles in Two Young H II Regions
Danforth, Charles W.; Nazé, Yaël; Chu, You-Hua +3 more
Massive stars are expected to produce wind-blown bubbles in the interstellar medium; however, ring nebulae, suggesting the existence of bubbles, are rarely seen around main-sequence O stars. To search for wind-blown bubbles around main-sequence O stars, we have obtained high-resolution Hubble Space Telescope WFPC2 images and high-dispersion echell…
Are There Blue, Massive E/S0 Galaxies at z<1? Kinematics of Blue Spheroidal Galaxy Candidates
Gebhardt, Karl; Faber, S. M.; Willmer, Christopher N. A. +5 more
Several recent studies find that 10%-50% of morphologically selected field early-type galaxies at redshifts z<~1 have blue colors indicative of recent star formation. Such ``blue spheroids'' might be massive early-type galaxies with active star formation, perhaps induced by recent merger events. Alternatively, they could be starbursting, low-ma…