High-resolution spectra of distant compact narrow emission line galaxies: Progrenitors of spheroidal galaxies
ABSTRACT Emission-line velocity widths have been determined for 17 faint (B approximately 20-23) very blue, compact galaxies whose redshifts range from z = 0.095 to 0.66. The spectra have a resolution of 8 Km/s and were taken with the HIRES echelle spectrograph of the Keck 10 m telescope. The galaxies are luminous with all but two within 1 mag of M(sub B) approximately -21. Yet they exhibit narrow velocity widths between sigma = 28-157 km/s, more consistent with typical values of extreme star-forming galaxies than with those of nearby spiral galaxies of similar luminosity. In particular, objects with sigma is less than or equal to 65 km/s follow the same correlations between sigma and both blue and H beta luminosities as those of nearby H II galaxies. These results strengthen the identification of H II glaxies as thier local counterparts. The blue colors and strong emission lines suggest these compact galaxies are undergoing a recent, strong burst of star formation. Like those which characterize some H II galaxies, this burst could be a nuclear star-forming event within a much larger, older stellar population. If the burst is instead a major episode in the total star-forming history, these distant galaxies could fade enough to match the low luminosities and surface brightnesses typical of nearby spheroidals like NGC 185 or NGC 205. Together with evidence for recent star formation, exponential light profiles, and subsolar metallicities, the postfading correlations between luminosity and velocity width and bewtween luminosity and surface brightness suggest that among the low-sigma galaxies, we may be witnessing, in situ, the progenitors of today's spheroidal galaxies.
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ABSTRACT: In this series of lectures I review recent observational progress in constraining models of galaxy formation and evolution highlighting the importance advances in addressing questions of the assembly history and origin of the Hubble sequence in the context of modern pictures of structure formation.03/2001;
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ABSTRACT: The Near-infrared Integral Field Spectrograph (NIFS) will be Australia's first Gemini instrument. NIFS is a near-infrared, imaging spectrograph that will be used with the ALTAIR facility adaptive optics system on Gemini North to perform near-diffraction-limited imaging spectroscopy over a 3.0'' × 3.0'' field of view with 0.1'' wide slitlets and a spectral resolving power of ~5300. NIFS will operate in the wavelength range from 0.94-2.50 mum where ALTAIR delivers its greatest gains. Its primary purpose is to study moderate-surface-brightness structures around discrete objects that are revealed at high spatial resolution by ALTAIR. NIFS will address a wide range of science from studies of Galactic star formation and the Galactic centre to the nature of disk galaxies at z ~ 1. Studies of the demographics of massive black holes in galactic nuclei and studies of the excitation conditions in the inner narrow-line regions of Seyfert galaxies have been identified as two core NIFS programs. These and other science drivers for NIFS are discussed.Publications of the Astronomical Society of Australia 01/2001; 18:41-57. · 3.12 Impact Factor
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ABSTRACT: We outline the DEEP project, which is a two-part (DEEP1, DEEP2) spectral survey of faint field galaxies with the Keck Telescopes. The data include internal kinematics of galaxies and HST imaging. The scientific goals include tracking galaxy formation and evolution, mapping distant large scale structures, and constraining cosmology. DEEP1 highlights are summarized.05/2003; 17:245-246.