David Sprayberry - Academia.edu (original) (raw)
Papers by David Sprayberry
The Astrophysical Journal, 1992
Discoveries and Research Prospects from 6- to 10-Meter-Class Telescopes II, 2003
The Keck II Adaptive Optics system and the NIRC2 camera provide a unique facility for high angula... more The Keck II Adaptive Optics system and the NIRC2 camera provide a unique facility for high angular resolution imaging and spectroscopy in the near infrared. In this paper, we present the result of a unique project to map the entire surface of Io in the thermal infrared (Lp band centered at 3.8 mum). This project was undertaken by a team
The Astrophysical Journal, 1992
Astro2010 the Astronomy and Astrophysics Decadal Survey, 2009
Astro2010 White Paper submitted to the State of the Profession Demographics (DEM); Facilities, Fu... more Astro2010 White Paper submitted to the State of the Profession Demographics (DEM); Facilities, Funding and Programs (FFP); and International and Private Partnership (IPP) Infrastructure Study Groups ... Authors: Jay Elias (NOAO), Bob Blum (NOAO), Joan Najita (NOAO), ...
Astrophys J, 1995
We have obtained 21 cm profiles and CCD surface photometry for a subset of field low surface brig... more We have obtained 21 cm profiles and CCD surface photometry for a subset of field low surface brightness (LSB) spiral galaxies found by a large survey using the Automated Plate Measuring (APM) machine. We find that the LSB spirals generally follow the same Tully-Fisher relations defined by a sample of higher surface brightness (HSB) galaxies drawn from the Ursa Major cluster, albeit with a considerably greater scatter. This general trend implies that LSB galaxies of a given total luminosity have mass-to-light ratios (M/L) similar to those of HSB galaxies of comparable total luminosity, despite their differences in luminosity density (i.e., surface brightness). We also find evidence that galaxies with extremely large half-lit radii (the Malin 1 cousins) tend to be excessively luminous for their rotation speeds. We find that, at a given profile width, the luminosity of an LSB galaxy relative to the Tully-Fisher relation seems to be weakly anticorrelated with gas richness, indicating that some of the higher scatter may be associated with the evolutionary status of the LSB galaxies. Finally, we find that the LSB galaxies tend to have higher total atomic gas masses than the Ursa Major comparison galaxies, depsite the genrally comparable optical luminosities between the two sets.
We use the NIRSPEC near-IR spectrometer on Keck II to obtain moderate resolution (R = 1540) spect... more We use the NIRSPEC near-IR spectrometer on Keck II to obtain moderate resolution (R = 1540) spectroscopy that shows conclusively that the C IV emission line in the z = 5.74 quasar SDSSp J104433.04-012502.2 is accompanied by broad, blueshifted C IV absorption. The line has a "balnicity index" of 900 km/s and a rest-frame equivalent width of 13.1 +/- 1.3
Ground-based and Airborne Instrumentation for Astronomy, 2006
ABSTRACT
Ground-based and Airborne Instrumentation for Astronomy, 2006
ABSTRACT
Ground-based and Airborne Instrumentation for Astronomy V, 2014
ABSTRACT The Dark Energy Spectroscopic instrument (DESI) is a 5000 fiber multi-object spectromete... more ABSTRACT The Dark Energy Spectroscopic instrument (DESI) is a 5000 fiber multi-object spectrometer system under development for installation on the National Optical Astronomy Observatory (NOAO) Kitt Peak 4m telescope (the Mayall telescope). DESI is designed to perform a 14,000° (square) galaxy and Quasi-Stellar Object (QSO) redshift survey to improve estimates of the dark energy equation of state. The survey design imposes numerous constraints on a prime focus corrector design, including field of view, geometrical blur, stability, fiber injection efficiency, zenith angle, mass and cost. The DESI baseline wide-field optical design described herein provides a 3.2° diameter field of view with six 0.8- 1.14m diameter lenses and an integral atmospheric dispersion compensator.
Discoveries and Research Prospects from 6- to 10-Meter-Class Telescopes II, 2003
The Keck II Adaptive Optics system and the NIRC2 camera provide a unique facility for high angula... more The Keck II Adaptive Optics system and the NIRC2 camera provide a unique facility for high angular resolution imaging and spectroscopy in the near infrared. In this paper, we present the result of a unique project to map the entire surface of Io in the thermal infrared (Lp band centered at 3.8 mum). This project was undertaken by a team
Ground-based and Airborne Instrumentation for Astronomy, 2006
The High-Resolution Near-InfraRed Spectrograph (HRNIRS) concept for the Gemini telescopes combine... more The High-Resolution Near-InfraRed Spectrograph (HRNIRS) concept for the Gemini telescopes combines a seeing limited R ~ 70000 cross-dispersed mode and an MCAO-fed near diffraction-limited R ~ 20000 multi-object mode into a single compact instrument operating over the 1 -5 µm range. The HRNIRS concept was developed in response to proposals issued through the Aspen instrument process by Gemini. Here we review the science drivers and key functional requirements. We present a general overview of the instrument and estimate the limiting performance.
Modeling, Systems Engineering, and Project Management for Astronomy II, 2006
The High-resolution Near-infrared Spectrograph (HRNIRS) concept for the Gemini telescopes combine... more The High-resolution Near-infrared Spectrograph (HRNIRS) concept for the Gemini telescopes combines a seeing-limited R ~ 7000 cross-dispersed mode and an MCAO-fed near diffraction-limited R ~ 20000 multi-object mode into a single compact instrument operating over the 0.9 - 5.5 mum range. We describe the systems engineering and performance modeling aspects of this study, emphasizing simulations of high-precision radial verlocity measurements
The Astrophysical Journal, 1997
The H I mass function (HiMF) for galaxies in the local universe is constructed from the results o... more The H I mass function (HiMF) for galaxies in the local universe is constructed from the results of the Arecibo H I Strip Survey, a blind extragalactic survey in the 21cm line. The survey consists of two strips covering in total ∼ 65 square degrees of sky, with a depth of cz = 7400 km s −1 and was optimized to detect column densities of neutral gas N HI > 10 18 cm −2 (5σ). The survey yielded 66 significant extragalactic signals of which approximately 50% are cataloged galaxies. No free floating H I clouds without stars are found. VLA follow-up observations of all signals have been used to obtain better measurements of the positions and fluxes and allow an alternate determination of the achieved survey sensitivity. The resulting HiMF has a shallow faint end slope (α ≈ 1.2), and is consistent with earlier estimates computed for the population of optically selected gas rich galaxies. This implies that there is not a large population of gas rich low luminosity or low surface brightness galaxies that has gone unnoticed by optical surveys. The influence of large scale structure on the determination of the HiMF from the Arecibo H I Strip Survey is tested by numerical experiments and was not found to affect the resulting HiMF significantly. The cosmological mass density of H I at the present time determined from the survey, Ω HI (z = 0) = (2.0 ± 0.5) × 10 −4 h −1 , is in good agreement with earlier estimates. We determine lower limits to the average
The Astronomical Journal, 2001
We present Ñux-calibrated spectra in the range 3500 to 8000 for the nuclear regions of 250 galaxi... more We present Ñux-calibrated spectra in the range 3500 to 8000 for the nuclear regions of 250 galaxies Ó and H I 21 cm line proÐles for 238 galaxies selected from the catalog of low surface brightness galaxies identiÐed in Automated Plate Measuring Facility (APM) scans of UK Schmidt Telescope survey plates. For the optical spectra, common nebular absorption-and emission-line equivalent widths and emissionline Ñuxes were measured with typical errors of about 20%. H I mass and velocity widths were measured from the 21 cm line emission, with 15% accuracy. Galaxies in this study span over 6 mag in surface brightness. Only about 20% of these galaxies show spectroscopic evidence of active galactic nuclei. Derived quantities such as synthetic colors, metallicity, star formation rate, the ratio of neutral hydrogen mass to blue light, and gas mass fraction are presented in a companion paper.
The Astronomical Journal, 1995
The Astronomical Journal, 2001
The Astronomical Journal, 1993
Publications of the Astronomical Society of Australia, 1997
Results from the Arecibo Hi Strip Survey, an unbiased extragalactic Hi survey, combined with opti... more Results from the Arecibo Hi Strip Survey, an unbiased extragalactic Hi survey, combined with optical and 21cm follow-up observations, determine the Hi Mass Function and the cosmological mass density of Hi at the present epoch. Both are consistent with earlier estimates, computed for the population of optically selected galaxies. This consistency occurs because, although the distribution of optical central surface brightnesses among galaxies is flat, we fail to find a population of galaxies with central surface brightnesses fainter than 24 B-mag arcsec −2 , even though there is no observational selection against them.
Monthly Notices of the Royal Astronomical Society, 2001
We measure the z = 0 B-band optical luminosity function (LF) for galaxies selected in a blind H i... more We measure the z = 0 B-band optical luminosity function (LF) for galaxies selected in a blind H i survey. The total LF of the H i selected sample is flat, with Schechter parameters M * = −19.38 +1.02 −0.62 + 5 log h 100 mag and α = −1.03 +0.25 −0.15 , in good agreement with LFs of optically selected late-type galaxies. Bivariate distribution functions of several galaxy parameters show that the H i density in the local Universe is more widely spread over galaxies of different size, central surface brightness, and luminosity than is the optical luminosity density. The number density of very low surface brightness (> 24.0 mag arcsec −2 ) gas-rich galaxies is considerably lower than that found in optical surveys designed to detect dim galaxies. This suggests that only a part of the population of LSB galaxies is gas rich and that the rest must be gas poor. However, we show that this gas-poor population must be cosmologically insignificant in baryon content. The contribution of gas-rich LSB galaxies (> 23.0 mag arcsec −2 ) to the local cosmological gas and luminosity density is modest (18 +6 −5 and 5 +2 −2 per cent respectively); their contribution to Ω matter is not well-determined, but probably < 11 per cent. These values are in excellent agreement with the low redshift results from the Hubble Deep Field.
The Astrophysical Journal, 1992
Discoveries and Research Prospects from 6- to 10-Meter-Class Telescopes II, 2003
The Keck II Adaptive Optics system and the NIRC2 camera provide a unique facility for high angula... more The Keck II Adaptive Optics system and the NIRC2 camera provide a unique facility for high angular resolution imaging and spectroscopy in the near infrared. In this paper, we present the result of a unique project to map the entire surface of Io in the thermal infrared (Lp band centered at 3.8 mum). This project was undertaken by a team
The Astrophysical Journal, 1992
Astro2010 the Astronomy and Astrophysics Decadal Survey, 2009
Astro2010 White Paper submitted to the State of the Profession Demographics (DEM); Facilities, Fu... more Astro2010 White Paper submitted to the State of the Profession Demographics (DEM); Facilities, Funding and Programs (FFP); and International and Private Partnership (IPP) Infrastructure Study Groups ... Authors: Jay Elias (NOAO), Bob Blum (NOAO), Joan Najita (NOAO), ...
Astrophys J, 1995
We have obtained 21 cm profiles and CCD surface photometry for a subset of field low surface brig... more We have obtained 21 cm profiles and CCD surface photometry for a subset of field low surface brightness (LSB) spiral galaxies found by a large survey using the Automated Plate Measuring (APM) machine. We find that the LSB spirals generally follow the same Tully-Fisher relations defined by a sample of higher surface brightness (HSB) galaxies drawn from the Ursa Major cluster, albeit with a considerably greater scatter. This general trend implies that LSB galaxies of a given total luminosity have mass-to-light ratios (M/L) similar to those of HSB galaxies of comparable total luminosity, despite their differences in luminosity density (i.e., surface brightness). We also find evidence that galaxies with extremely large half-lit radii (the Malin 1 cousins) tend to be excessively luminous for their rotation speeds. We find that, at a given profile width, the luminosity of an LSB galaxy relative to the Tully-Fisher relation seems to be weakly anticorrelated with gas richness, indicating that some of the higher scatter may be associated with the evolutionary status of the LSB galaxies. Finally, we find that the LSB galaxies tend to have higher total atomic gas masses than the Ursa Major comparison galaxies, depsite the genrally comparable optical luminosities between the two sets.
We use the NIRSPEC near-IR spectrometer on Keck II to obtain moderate resolution (R = 1540) spect... more We use the NIRSPEC near-IR spectrometer on Keck II to obtain moderate resolution (R = 1540) spectroscopy that shows conclusively that the C IV emission line in the z = 5.74 quasar SDSSp J104433.04-012502.2 is accompanied by broad, blueshifted C IV absorption. The line has a "balnicity index" of 900 km/s and a rest-frame equivalent width of 13.1 +/- 1.3
Ground-based and Airborne Instrumentation for Astronomy, 2006
ABSTRACT
Ground-based and Airborne Instrumentation for Astronomy, 2006
ABSTRACT
Ground-based and Airborne Instrumentation for Astronomy V, 2014
ABSTRACT The Dark Energy Spectroscopic instrument (DESI) is a 5000 fiber multi-object spectromete... more ABSTRACT The Dark Energy Spectroscopic instrument (DESI) is a 5000 fiber multi-object spectrometer system under development for installation on the National Optical Astronomy Observatory (NOAO) Kitt Peak 4m telescope (the Mayall telescope). DESI is designed to perform a 14,000° (square) galaxy and Quasi-Stellar Object (QSO) redshift survey to improve estimates of the dark energy equation of state. The survey design imposes numerous constraints on a prime focus corrector design, including field of view, geometrical blur, stability, fiber injection efficiency, zenith angle, mass and cost. The DESI baseline wide-field optical design described herein provides a 3.2° diameter field of view with six 0.8- 1.14m diameter lenses and an integral atmospheric dispersion compensator.
Discoveries and Research Prospects from 6- to 10-Meter-Class Telescopes II, 2003
The Keck II Adaptive Optics system and the NIRC2 camera provide a unique facility for high angula... more The Keck II Adaptive Optics system and the NIRC2 camera provide a unique facility for high angular resolution imaging and spectroscopy in the near infrared. In this paper, we present the result of a unique project to map the entire surface of Io in the thermal infrared (Lp band centered at 3.8 mum). This project was undertaken by a team
Ground-based and Airborne Instrumentation for Astronomy, 2006
The High-Resolution Near-InfraRed Spectrograph (HRNIRS) concept for the Gemini telescopes combine... more The High-Resolution Near-InfraRed Spectrograph (HRNIRS) concept for the Gemini telescopes combines a seeing limited R ~ 70000 cross-dispersed mode and an MCAO-fed near diffraction-limited R ~ 20000 multi-object mode into a single compact instrument operating over the 1 -5 µm range. The HRNIRS concept was developed in response to proposals issued through the Aspen instrument process by Gemini. Here we review the science drivers and key functional requirements. We present a general overview of the instrument and estimate the limiting performance.
Modeling, Systems Engineering, and Project Management for Astronomy II, 2006
The High-resolution Near-infrared Spectrograph (HRNIRS) concept for the Gemini telescopes combine... more The High-resolution Near-infrared Spectrograph (HRNIRS) concept for the Gemini telescopes combines a seeing-limited R ~ 7000 cross-dispersed mode and an MCAO-fed near diffraction-limited R ~ 20000 multi-object mode into a single compact instrument operating over the 0.9 - 5.5 mum range. We describe the systems engineering and performance modeling aspects of this study, emphasizing simulations of high-precision radial verlocity measurements
The Astrophysical Journal, 1997
The H I mass function (HiMF) for galaxies in the local universe is constructed from the results o... more The H I mass function (HiMF) for galaxies in the local universe is constructed from the results of the Arecibo H I Strip Survey, a blind extragalactic survey in the 21cm line. The survey consists of two strips covering in total ∼ 65 square degrees of sky, with a depth of cz = 7400 km s −1 and was optimized to detect column densities of neutral gas N HI > 10 18 cm −2 (5σ). The survey yielded 66 significant extragalactic signals of which approximately 50% are cataloged galaxies. No free floating H I clouds without stars are found. VLA follow-up observations of all signals have been used to obtain better measurements of the positions and fluxes and allow an alternate determination of the achieved survey sensitivity. The resulting HiMF has a shallow faint end slope (α ≈ 1.2), and is consistent with earlier estimates computed for the population of optically selected gas rich galaxies. This implies that there is not a large population of gas rich low luminosity or low surface brightness galaxies that has gone unnoticed by optical surveys. The influence of large scale structure on the determination of the HiMF from the Arecibo H I Strip Survey is tested by numerical experiments and was not found to affect the resulting HiMF significantly. The cosmological mass density of H I at the present time determined from the survey, Ω HI (z = 0) = (2.0 ± 0.5) × 10 −4 h −1 , is in good agreement with earlier estimates. We determine lower limits to the average
The Astronomical Journal, 2001
We present Ñux-calibrated spectra in the range 3500 to 8000 for the nuclear regions of 250 galaxi... more We present Ñux-calibrated spectra in the range 3500 to 8000 for the nuclear regions of 250 galaxies Ó and H I 21 cm line proÐles for 238 galaxies selected from the catalog of low surface brightness galaxies identiÐed in Automated Plate Measuring Facility (APM) scans of UK Schmidt Telescope survey plates. For the optical spectra, common nebular absorption-and emission-line equivalent widths and emissionline Ñuxes were measured with typical errors of about 20%. H I mass and velocity widths were measured from the 21 cm line emission, with 15% accuracy. Galaxies in this study span over 6 mag in surface brightness. Only about 20% of these galaxies show spectroscopic evidence of active galactic nuclei. Derived quantities such as synthetic colors, metallicity, star formation rate, the ratio of neutral hydrogen mass to blue light, and gas mass fraction are presented in a companion paper.
The Astronomical Journal, 1995
The Astronomical Journal, 2001
The Astronomical Journal, 1993
Publications of the Astronomical Society of Australia, 1997
Results from the Arecibo Hi Strip Survey, an unbiased extragalactic Hi survey, combined with opti... more Results from the Arecibo Hi Strip Survey, an unbiased extragalactic Hi survey, combined with optical and 21cm follow-up observations, determine the Hi Mass Function and the cosmological mass density of Hi at the present epoch. Both are consistent with earlier estimates, computed for the population of optically selected galaxies. This consistency occurs because, although the distribution of optical central surface brightnesses among galaxies is flat, we fail to find a population of galaxies with central surface brightnesses fainter than 24 B-mag arcsec −2 , even though there is no observational selection against them.
Monthly Notices of the Royal Astronomical Society, 2001
We measure the z = 0 B-band optical luminosity function (LF) for galaxies selected in a blind H i... more We measure the z = 0 B-band optical luminosity function (LF) for galaxies selected in a blind H i survey. The total LF of the H i selected sample is flat, with Schechter parameters M * = −19.38 +1.02 −0.62 + 5 log h 100 mag and α = −1.03 +0.25 −0.15 , in good agreement with LFs of optically selected late-type galaxies. Bivariate distribution functions of several galaxy parameters show that the H i density in the local Universe is more widely spread over galaxies of different size, central surface brightness, and luminosity than is the optical luminosity density. The number density of very low surface brightness (> 24.0 mag arcsec −2 ) gas-rich galaxies is considerably lower than that found in optical surveys designed to detect dim galaxies. This suggests that only a part of the population of LSB galaxies is gas rich and that the rest must be gas poor. However, we show that this gas-poor population must be cosmologically insignificant in baryon content. The contribution of gas-rich LSB galaxies (> 23.0 mag arcsec −2 ) to the local cosmological gas and luminosity density is modest (18 +6 −5 and 5 +2 −2 per cent respectively); their contribution to Ω matter is not well-determined, but probably < 11 per cent. These values are in excellent agreement with the low redshift results from the Hubble Deep Field.