The Nature of Optically Dull Active Galactic Nuclei in COSMOS (2009)
Trump, Jonathan R., Impey, Chris D., Taniguchi, Yoshi, Brusa, Marcella, Civano, Francesca, Elvis, Martin, ...
We present infrared, optical, and X-ray data of 48 X-ray bright, optically dull AGNs in the COSMOS field. These objects exhibit the X-ray luminosity of an active galactic nucleus (AGN) but lack broad...
Observational limits on type 1 active galactic nucleus rate in COSMOS (2009)
Trump, Jonathan R., Impey, Chris D., Kelly, Brandon C., Elvis, Martin, Merloni, A., Bongiorno, Angela, ...
We present black hole masses and accretion rates for 182 Type 1 active galactic nuclei (AGNs) in COSMOS. We estimate masses using the scaling relations for the broad H β, Mg ii, and C iv emission...
The COSMOS Active Galactic Nucleus Spectroscopic Survey. I. XMM-Newton Counterparts (2009)
Trump, Jonathan R., Impey, Chris D., Elvis, Martin, McCarthy, Patrick J., Huchra, John P., Brusa, Marcella, ...
We present optical spectroscopy for an X-ray and optical flux-limited sample of 677 XMM-Newton selected targets covering the 2 deg^2 Cosmic Evolution Survey field, with a yield of 485 high-confidence...
Observational Limits on Type 1 AGN Accretion Rate in COSMOS (2009)
Trump, Jonathan R., Impey, Chris D., Kelly, Brandon C., Elvis, Martin, Merloni, Andrea, Bongiorno, Angela, ...
We present black hole masses and accretion rates for 182 Type 1 AGN in COSMOS. We estimate masses using the scaling relations for the broad Hb, MgII, and CIV emission lines in the redshift ranges 0.16
The COSMOS active galactic nucleus spectroscopic survey - I. XMM-Newton counterparts (2009)
Trump, Jonathan R., Impey, Chris D., Elvis, Martin, McCarthy, Patrick J., Huchra, John P., Brusa, Marcella, ...
Observational limits on type 1 active galactic nucleus accretion rate in COSMOS (2009)
Trump, Jonathan R., Impey, Chris D., Kelly, Brandon C., Elvis, Martin, Merloni, Andrea, Bongiorno, Angela, ...
The COSMOS AGN Spectroscopic Survey I: XMM Counterparts (2008)
Trump, Jonathan R., Impey, Chris D., Elvis, Martin, McCarthy, Patrick J., Huchra, John P., Brusa, Marcella, ...
We present optical spectroscopy for an X-ray and optical flux-limited sample of 677 XMM-Newton selected targets covering the 2 deg^2 COSMOS field, with a yield of 485 high-confidence redshifts. The...
2MTF I. The Tully-Fisher Relation in the 2MASS J, H and K Bands (2007)
Masters, Karen L., Springob, Christopher M., Huchra, John P.
The 2 Micron All-Sky Survey (2MASS) Tully-Fisher Survey (2MTF) aims to measure Tully-Fisher (TF) distances to all bright inclined spirals in the 2MASS Redshift Survey (2MRS). Essential to this...
Bas'ilio X. Santiago, 2 (2007)
Sune Hermit, Ofer Lahav, Michael A. Strauss, Alan Dressler, John P. Huchra
T E X style file v1.4) The two-point correlation function and morphological
Anne Turner, Laura Ferrarese, Peter Il. Stetson, John A. Grahan, Ilarry Maclore, N. A. Silbernlann, ...
Received! accepted.—
Sune Hermit, Basílio X. Santiago, Ofer Lahav, Michael A. Strauss, Alan Dressler, John P. Huchra
We study the clustering of galaxies in real and redshift space using the Optical Redshift Survey (ORS). We estimate the two point correlation function in redshift space, ¸(s), for several subsamples...
Basílio X. Santiago, Bas'ilio X. Santiago, Michael A. Strauss, Ofer Lahav, Marc Davis, Alan Dressler, ...
We quantify the effects of Galactic extinction on the derived luminosity and diameter functions and on the density field of a redshift sample. Galaxy magnitudes are more affected by extinction than...
The Updated Zwicky Catalog (UZC) (2007)
Emilio E. Falco, Michael J. Kurtz, Margaret J. Geller, John P. Huchra, James Peters
The Zwicky Catalog of galaxies (ZC), with mZw 15:5, has been the basis for the Center for Astrophysics (CfA) redshift surveys. To date, analyses of the ZC and redshift surveys based on it have relied...
Saurabh Jha, Peter M. Garnavich, Robert P. Kirshner, Peter Challis, Alicia M. Soderberg, Lucas M. Macri, ...
We present optical and near-infrared photometry and spectroscopy of the Type Ia SN 1998bu in the Leo I Group galaxy M96 (NGC 3368). The data set consists of 356 photometric measurements and 29...
Groups of Galaxies in the Two Micron All Sky Redshift Survey (2007)
Crook, Aidan C., Huchra, John P., Martimbeau, Nathalie, Masters, Karen L., Jarrett, Tom, Macri, Lucas M.
We present the results of applying a percolation algorithm to the initial release of the Two Micron All Sky Survey Extended Source Catalog, using subsequently measured redshifts for almost all of the...
Magellan spectroscopy of AGN candidates in the COSMOS field (2007)
Trump, Jonathan R., Impey, Chris D., McCarthy, Patrick J., Elvis, Martin, Huchra, John P., Brusa, Marcella, ...
Magellan spectroscopy of AGN candidates in the COSMOS field (2007)
Trump, Jonathan R., Impey, Chris D., McCarthy, Patrick J., Elvis, Martin, Huchra, John P., Brusa, Marcella, ...
We present spectroscopic redshifts for the first 466 X-ray- and radio-selected AGN targets in the 2 deg2 COSMOS field. Spectra were obtained with the IMACS instrument on the Magellan (Baade)...
A survey of AGN and supermassive black holes in the COSMOS survey (2007)
Impey, Chris D., Trump, Jon R., McCarthy, Pat J., Elvis, Martin, Huchra, John P., Scoville, Nick Z., ...
Not Available
Reconstructed density and velocity fields from the 2MASS Redshift Survey (2006)
Erdoğdu, Pirin, Lahav, Ofer, Huchra, John P., Colless, Matthew, Cutri, Roc M., Falco, Emilio, ...
We present the reconstructed real-space density and the predicted velocity fields from the Two-Micron All-Sky Redshift Survey (2MRS). The 2MRS is the densest all-sky redshift survey to date and...
Reconstructed Density and Velocity Fields from the 2MASS Redshift Survey (2006)
Erdogdu, Pirin, Lahav, Ofer, Huchra, John P., Colless, Matthew, Cutri, Roc M., Falco, Emilio, ...
We present the reconstructed real-space density and the predicted velocity fields from the Two Mass Redshift Survey (2MRS). The 2MRS is the densest all-sky redshift survey to date and includes about...
The ROSAT north ecliptic pole survey: the X-ray catalog (2006)
Henry, J. Patrick, Mullis, Christopher R., Voges, Wolfgang, Böhringer, Hans, Briel, Ulrich G., Gioia, Isabella M., ...
Reconstructed density and velocity fields from the 2MASS Redshift Survey (2006)
Erdoğdu, Pirin, Lahav, Ofer, Mader, Jeff, Martimbeau, Nathalie, Pahre, Michael A, Parker, Quentin A, ...
We present the reconstructed real-space density and the predicted velocity fields from the Two-Micron All-Sky Redshift Survey (2MRS). The 2MRS is the densest all-sky redshift survey to date and...
Reconstructed density and velocity fields from the 2MASS Redshift Survey (2006)
Erdoğdu, Pirin, Lahav, Ofer, Mader, Jeff, Martimbeau, Nathalie, Pahre, Michael A, Parker, Quentin A, ...
We present the reconstructed real-space density and the predicted velocity fields from the Two-Micron All-Sky Redshift Survey (2MRS). The 2MRS is the densest all-sky redshift survey to date and...
Beasley, Michael A., Brodie, Jean P., Strader, Jay, Forbes, Duncan A., Proctor, Robert N., Barmby, Pauline, ...
We derive ages, metallicities, and abundance ratios ([α/Fe]) from the integrated spectra of 23 globular clusters in M31 by employing multivariate fits to two different stellar population models. We...
Beasley, Michael A., Brodie, Jean P., Strader, Jay, Forbes, Duncan A., Proctor, Robert N., Barmby, Pauline, ...
We derive ages, metallicities, and abundance ratios ([α/Fe]) from the integrated spectra of 23 globular clusters in M31 by employing multivariate fits to two different stellar population models. We...
Beasley, Michael A., Brodie, Jean P., Strader, Jay, Forbes, Duncan A., Proctor, Robert N., Barmby, Pauline, ...
We derive ages, metallicities, and abundance ratios ([α/Fe]) from the integrated spectra of 23 globular clusters in M31 by employing multivariate fits to two different stellar population models. We...
Beasley, Michael A., Brodie, Jean P., Strader, Jay, Forbes, Duncan A., Proctor, Robert N., Barmby, Pauline, ...
We derive ages, metallicities, and abundance ratios ([α/Fe]) from the integrated spectra of 23 globular clusters in M31 by employing multivariate fits to two different stellar population models. We...
The chemical properties of Milky Way and M31 globular clusters I : a comparative study (2004)
Beasley, Michael A., Brodie, Jean P., Strader, Jay, Forbes, Duncan A., Proctor, Robert N., Barmby, Pauline, ...
Abstract not available.
Burstein, David, Li, Yong, Freeman, Ken C., Norris, John, Bessell, Michael S., Bland-Hawthorn, Joss, ...
We find that the globular cluster (GC) systems of the Milky Way and of our neighboring spiral galaxy, M31, comprise two distinct entities, differing in three respects. First, M31 has a set of young...
The chemical properties of Milky Way and M31 globular clusters I : a comparative study (2004)
Beasley, Michael A., Brodie, Jean P., Strader, Jay, Forbes, Duncan A., Proctor, Robert N., Barmby, Pauline, ...
Abstract not available.
Burstein, David, Li, Yong, Freeman, Ken C., Norris, John, Bessell, Michael S., Bland-Hawthorn, Joss, ...
We find that the globular cluster (GC) systems of the Milky Way and of our neighboring spiral galaxy, M31, comprise two distinct entities, differing in three respects. First, M31 has a set of young...
The chemical properties of Milky Way and M31 globular clusters I : a comparative study (2004)
Beasley, Michael A., Brodie, Jean P., Strader, Jay, Forbes, Duncan A., Proctor, Robert N., Barmby, Pauline, ...
Abstract not available.
The chemical properties of Milky Way and M31 globular clusters I : a comparative study (2004)
Beasley, Michael A., Brodie, Jean P., Strader, Jay, Forbes, Duncan A., Proctor, Robert N., Barmby, Pauline, ...
Abstract not available.
Burstein, David, Li, Yong, Freeman, Ken C., Norris, John, Bessell, Michael S., Bland-Hawthorn, Joss, ...
We find that the globular cluster (GC) systems of the Milky Way and of our neighboring spiral galaxy, M31, comprise two distinct entities, differing in three respects. First, M31 has a set of young...
The chemical properties of Milky Way and M31 globular clusters I : a comparative study (2004)
Beasley, Michael A., Brodie, Jean P., Strader, Jay, Forbes, Duncan A., Proctor, Robert N., Barmby, Pauline, ...
Abstract not available.
Burstein, David, Li, Yong, Freeman, Ken C., Norris, John, Bessell, Michael S., Bland-Hawthorn, Joss, ...
We find that the globular cluster (GC) systems of the Milky Way and of our neighboring spiral galaxy, M31, comprise two distinct entities, differing in three respects. First, M31 has a set of young...
Spectroscopy of globular clusters in the Fornax dwarf galaxy (2003)
Strader, Jay, Brodie, Jean P., Forbes, Duncan A., Beasley, Michael A., Huchra, John P.
We present low-resolution, integrated Keck spectra of the five globular clusters (GCs) of the Fornax dwarf spheroidal galaxy. We find a tentative age spread among the clusters, with the GC H5 younger...
Spectroscopy of globular clusters in the Fornax dwarf galaxy (2003)
Strader, Jay, Brodie, Jean P., Forbes, Duncan A., Beasley, Michael A., Huchra, John P.
We present low-resolution, integrated Keck spectra of the five globular clusters (GCs) of the Fornax dwarf spheroidal galaxy. We find a tentative age spread among the clusters, with the GC H5 younger...
Spectroscopy of globular clusters in the Fornax dwarf galaxy (2003)
Strader, Jay, Brodie, Jean P., Forbes, Duncan A., Beasley, Michael A., Huchra, John P.
We present low-resolution, integrated Keck spectra of the five globular clusters (GCs) of the Fornax dwarf spheroidal galaxy. We find a tentative age spread among the clusters, with the GC H5 younger...
Spectroscopy of globular clusters in the Fornax dwarf galaxy (2003)
Strader, Jay, Brodie, Jean P., Forbes, Duncan A., Beasley, Michael A., Huchra, John P.
We present low-resolution, integrated Keck spectra of the five globular clusters (GCs) of the Fornax dwarf spheroidal galaxy. We find a tentative age spread among the clusters, with the GC H5 younger...
Final results from the Hubble Space Telescope key project to measure the Hubble Constant (2001)
Freedman, Wendy L., Madore, Barry F., Gibson, Brad K., Ferrarese, Laura, Kelson, Daniel D., Sakai, Shoko, ...
We present here the final results of the Hubble Space Telescope (HST) Key Project to measure the Hubble constant. We summarize our method, the results, and the uncertainties, tabulate our revised...
Macri, Lucas M., Calzetti, Daniela, Freedman, Wendy L., Gibson, Brad K., Graham, John A., Huchra, John P., ...
We present the results of near-infrared observations of extragalactic Cepheids made with the Near-Infrared Camera and Multi-Object Spectrometer on board the Hubble Space Telescope (HST). The...
Final results from the Hubble Space Telescope key project to measure the Hubble Constant (2001)
Freedman, Wendy L., Madore, Barry F., Gibson, Brad K., Ferrarese, Laura, Kelson, Daniel D., Sakai, Shoko, ...
We present here the final results of the Hubble Space Telescope (HST) Key Project to measure the Hubble constant. We summarize our method, the results, and the uncertainties, tabulate our revised...
Macri, Lucas M., Calzetti, Daniela, Freedman, Wendy L., Gibson, Brad K., Graham, John A., Huchra, John P., ...
We present the results of near-infrared observations of extragalactic Cepheids made with the Near-Infrared Camera and Multi-Object Spectrometer on board the Hubble Space Telescope (HST). The...
Final results from the Hubble Space Telescope key project to measure the Hubble Constant (2001)
Freedman, Wendy L., Madore, Barry F., Gibson, Brad K., Ferrarese, Laura, Kelson, Daniel D., Sakai, Shoko, ...
We present here the final results of the Hubble Space Telescope (HST) Key Project to measure the Hubble constant. We summarize our method, the results, and the uncertainties, tabulate our revised...
Macri, Lucas M., Calzetti, Daniela, Freedman, Wendy L., Gibson, Brad K., Graham, John A., Huchra, John P., ...
We present the results of near-infrared observations of extragalactic Cepheids made with the Near-Infrared Camera and Multi-Object Spectrometer on board the Hubble Space Telescope (HST). The...
Final results from the Hubble Space Telescope key project to measure the Hubble Constant (2001)
Freedman, Wendy L., Madore, Barry F., Gibson, Brad K., Ferrarese, Laura, Kelson, Daniel D., Sakai, Shoko, ...
We present here the final results of the Hubble Space Telescope (HST) Key Project to measure the Hubble constant. We summarize our method, the results, and the uncertainties, tabulate our revised...
Macri, Lucas M., Calzetti, Daniela, Freedman, Wendy L., Gibson, Brad K., Graham, John A., Huchra, John P., ...
We present the results of near-infrared observations of extragalactic Cepheids made with the Near-Infrared Camera and Multi-Object Spectrometer on board the Hubble Space Telescope (HST). The...
The 2MASS Luminosity, Velocity, and Mass (2001)
Functions Of Galaxies, Michael A. Pahre, Chris S. Kochanek, Emilio E. Falco, John P. Huchra
The velocity function (VF) of galaxies is analogous to the luminosity function (LF), but a more direct tool for comparing observations and theory. The 2MASS LF is calculated here for a local sample...
Final results from the Hubble Space Telescope key project to measure the Hubble Constant (2001)
Freedman, Wendy L., Madore, Barry F., Gibson, Brad K., Ferrarese, Laura, Kelson, Daniel D., Sakai, Shoko, ...
We present here the final results of the Hubble Space Telescope (HST) Key Project to measure the Hubble constant. We summarize our method, the results, and the uncertainties, tabulate our revised...
Macri, Lucas M., Calzetti, Daniela, Freedman, Wendy L., Gibson, Brad K., Graham, John A., Huchra, John P., ...
We present the results of near-infrared observations of extragalactic Cepheids made with the Near-Infrared Camera and Multi-Object Spectrometer on board the Hubble Space Telescope (HST). The...
M31 globular clusters: colors and metallicities (2000)
Barmby, Pauline, Huchra, John P., Brodie, Jean P., Forbes, Duncan A., Schroder, Linda L., Grillmair, Carl J.
We present a new catalog of photometric and spectroscopic data on M31 globular clusters (GCs). The catalog includes new optical and near-infrared photometry for a substantial fraction of the 435...
M31 globular clusters: colors and metallicities (2000)
Barmby, Pauline, Huchra, John P., Brodie, Jean P., Forbes, Duncan A., Schroder, Linda L., Grillmair, Carl J.
We present a new catalog of photometric and spectroscopic data on M31 globular clusters (GCs). The catalog includes new optical and near-infrared photometry for a substantial fraction of the 435...
Mould, Jeremy R, Huchra, John P, Freedman, Wendy L, Kennicutt Jr, Robert C, Ferrarese, Laura, Ford, Holland C, ...
Since the launch of the Hubble Space Telescope nine years ago, Cepheid distances to 25 galaxies have been determined for the purpose of calibrating secondary distance indicators. A variety of these...
The Updated Zwicky Catalog (UZC) (1999)
Falco, Emilio E., Kurtz, Michael J., Geller, Margaret J., Huchra, John P., Peters, James, Berlind, Perry, ...
The Zwicky Catalog of galaxies (ZC), with m_Zw
Tyson, J. Anthony, Fischer, Philippe, Guhathakurta, Puragra, McIlroy, Peter, Wenk, R. A., Huchra, John P., ...
Deep Hubble Space Telescope Wide Field Camera (WFC-1) imaging of a region 3farcm7 east of the V = 13 mag Seyfert galaxy NGC 5548 in the F555W and F785LP bands, and deep ground-based V and I imaging,...
Keck spectroscopy of candidate proto-globular clusters in NGC 1275 (1998)
Brodie, Jean P., Schroder, Linda L., Huchra, John P., Phillips, Andrew C., Kissler-Patig, Markus, Forbes, Duncan A.
Keck spectroscopy of five proto-globular cluster candidates in NGC 1275 has been combined with Hubble Space Telescope Wide Field Planetary Camera 2 photometry to explore the nature and origin of...
Keck spectroscopy of globular clusters around NGC 1399 (1998)
Kissler-Patig, Markus, Brodie, Jean P., Schroder, Linda L., Forbes, Duncan A., Grillmair, Carl J., Huchra, John P.
We report moderate-resolution, high signal-to-noise ratio spectroscopy of globular clusters around NGC 1399, the central cD galaxy in the Fornax Cluster. We address issues as diverse as elemental...
Keck spectroscopy of candidate proto-globular clusters in NGC 1275 (1998)
Brodie, Jean P., Schroder, Linda L., Huchra, John P., Phillips, Andrew C., Kissler-Patig, Markus, Forbes, Duncan A.
Keck spectroscopy of five proto-globular cluster candidates in NGC 1275 has been combined with Hubble Space Telescope Wide Field Planetary Camera 2 photometry to explore the nature and origin of...
Tyson, J. Anthony, Fischer, Philippe, Guhathakurta, Puragra, McIlroy, Peter, Wenk, R. A., Huchra, John P., ...
Deep Hubble Space Telescope Wide Field Camera (WFC-1) imaging of a region 3farcm7 east of the V = 13 mag Seyfert galaxy NGC 5548 in the F555W and F785LP bands, and deep ground-based V and I imaging,...
Keck spectroscopy of globular clusters around NGC 1399 (1998)
Kissler-Patig, Markus, Brodie, Jean P., Schroder, Linda L., Forbes, Duncan A., Grillmair, Carl J., Huchra, John P.
We report moderate-resolution, high signal-to-noise ratio spectroscopy of globular clusters around NGC 1399, the central cD galaxy in the Fornax Cluster. We address issues as diverse as elemental...
The HST Medium Deep Survey: progress towards resolution of the faint blue galaxy problem (1997)
Griffiths, Richard, Ratnatunga, Kavan U., Casertano, Stefano, Im, Myungshin, Neuschaefer, Lyman W., Ostrander, Eric J., ...
WFPC2 on HST has provided the means to make rapid progress towards solving a long-standing problem in observational cosmology, viz. the nature of the objects contributing to the faint blue galaxy...
Hubble Space Telescope imaging of the globular cluster system around NGC 5846 (1997)
Forbes, Duncan A., Brodie, Jean P., Huchra, John P.
Bimodal globular cluster metallicity distributions have now been seen in a handful of large ellipticals. Here we report the discovery of a bimodal distribution in the dominant group elliptical NGC...
Daya Rawson, Lucas M. Macri, Jeremy R. Mould, John P. Huchra, Wendy L. Freedman, Robert C. Kennicutt, ...
We report on the discovery of Cepheids in the field spiral galaxy NGC 3621, based on observations made with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope (HST). NGC 3621...
The HST Medium Deep Survey: progress towards resolution of the faint blue galaxy problem (1997)
Griffiths, Richard, Ratnatunga, Kavan U., Casertano, Stefano, Im, Myungshin, Neuschaefer, Lyman W., Ostrander, Eric J., ...
WFPC2 on HST has provided the means to make rapid progress towards solving a long-standing problem in observational cosmology, viz. the nature of the objects contributing to the faint blue galaxy...
Hubble Space Telescope imaging of the globular cluster system around NGC 5846 (1997)
Forbes, Duncan A., Brodie, Jean P., Huchra, John P.
Bimodal globular cluster metallicity distributions have now been seen in a handful of large ellipticals. Here we report the discovery of a bimodal distribution in the dominant group elliptical NGC...
The morphology of faint galaxies in medium deep survey images using WFPC2 (1994)
Griffiths, Richard, Casertano, Stefano, Ratnatunga, Kavan U., Neuschaefer, Lyman W., Ellis, Richard S., Gilmore, Gerard F., ...
First results from HST Medium Deep Survey images taken with WFPC2 demonstrate that galaxy classifications can be reliably performed to magnitudes I814 less-than-or-similar-to 22.0 in the F815W band....
Windhorst, Rogier A., Schmidtke, Paul C., Pascarelle, Sebastian M., Gordon, J. M., Griffiths, Richard, Ratnatunga, Kavan U., ...
We present isophotal profiles of six faint field galaxies from some of the first deep images taken for the Hubble Space Telescope (HST) Medium Deep Survey (MDS). These have redshifts in the range...
Griffiths, Richard, Ratnatunga, Kavan U., Neuschaefer, Lyman W., Casertano, Stefano, Im, Myungshin, Wyckoff, Eric W., ...
We present results from the Medium Deep Survey (MDS), a Key Project using the Hubble Space Telescope. Wide Field Camera images of random fields have been taken in "parallel mode" with an effective...
The morphology of faint galaxies in medium deep survey images using WFPC2 (1994)
Griffiths, Richard, Casertano, Stefano, Ratnatunga, Kavan U., Neuschaefer, Lyman W., Ellis, Richard S., Gilmore, Gerard F., ...
First results from HST Medium Deep Survey images taken with WFPC2 demonstrate that galaxy classifications can be reliably performed to magnitudes I814 less-than-or-similar-to 22.0 in the F815W band....
Windhorst, Rogier A., Schmidtke, Paul C., Pascarelle, Sebastian M., Gordon, J. M., Griffiths, Richard, Ratnatunga, Kavan U., ...
We present isophotal profiles of six faint field galaxies from some of the first deep images taken for the Hubble Space Telescope (HST) Medium Deep Survey (MDS). These have redshifts in the range...
Griffiths, Richard, Ratnatunga, Kavan U., Neuschaefer, Lyman W., Casertano, Stefano, Im, Myungshin, Wyckoff, Eric W., ...
We present results from the Medium Deep Survey (MDS), a Key Project using the Hubble Space Telescope. Wide Field Camera images of random fields have been taken in "parallel mode" with an effective...
The nature of Markarian galaxies and studies of star formation in blue galaxies. (1977)
Thesis (Ph. D.)--California Institute of Technology, 1977.