Selected Papers:

(Observations of Supernovae, External Galaxies and Black Holes)

• Current paper in postscript format DISCOVERY OF A NUCLEAR X-RAY SOURCE IN NGC 7331: EVIDENCE FOR A MASSIVE BLACK HOLE ApJ Letters 508, L33 (1998)
• Current paper in postscript format THE PROBABLE DETECTION OF SN 1923A: THE OLDEST RADIO SUPERNOVA? ApJ, 508, 664 (1998)
• Current paper in postscript format THE FADING RADIO EMISSION FROM SN 1961V: EVIDENCE FOR A TYPE II PECULIAR SUPERNOVA? , astro-ph/0104235, AJ, 122, 283 (2001)
• Current paper in postscript format THE CONTINUING RADIO EVOLUTION OF SUPERNOVA 1970G, astro-ph/0108262, ApJ Letters, 559, L139 (2001)
• Current paper in postscript format THE A SEARCH FOR RADIO EMISSION FROM SUPERNOVAE WITH AGES FROM ABOUT ONE WEEK TO MORE THAN 80 YEARS, astro-ph/0204466, ApJ, 573, 306 (2002)
• Current paper in pdf format THE NATURE OF SN 1961V, astro-ph/0402473, Astron. J., 127, 2850 (2004)
• Current paper in pdf format PRELIMINARY RADIO ANALYSIS FROM AN X-RAY/RADIO SURVEY OF NEARBY SPIRAL GALAXIES, in ``X-Ray and Radio Connections'', eds. Sjouwerman, L.O.& Dyer, K.K., http://www.aoc.nrao.edu/events/xraydio (2005)
• Current paper in pdf format A RADIO AND X-RAY STUDY OF HISTORICAL SUPERNOVAE IN M83, astro-ph/0511202, Astron. J., 131, 889 (2006)
• Current paper in pdf format A STUDY OF COMPACT RADIO SOURCES IN NEARBY FACE-ON SPIRAL GALAXIES. I. LONG TERM EVOLUTION OF M83 astro-ph/0603850, Astron. J., 132, 310 (2006) Radio Image of M83
• Current paper in pdf format A STUDY OF COMPACT RADIO SOURCES IN NEARBY FACE-ON SPIRAL GALAXIES. II. MULTIWAVELENGTH ANALYSES OF SOURCES IN M51, astro-ph/0702310, Astron. J., 133, 2559 (2007) The Cover of the Astronomical Journal, June 2007,

(Abundances, Nucleosynthesis, Stellar Evolution and Ages)

1998:

• Current paper in postscript format R-PROCESS IN COLLAPSING O/NE/MG CORES ApJ Letters, 493, L101 (1998)
• Current paper in postscript format HST OBSERVATIONS OF NEUTRON-CAPTURE ELEMENTS IN VERY METAL-POOR STARS ApJ, 496, 235 (1998)
• Current paper in postscript format STELLAR ABUNDANCE OBSERVATIONS in Stellar Evolution, Stellar Explosions and Galactic Chemical Evolution, ed. A. Metzacappa (Bristol: Institute of Physics), 621 (1998)
• Current paper in postscript format GHRS OBSERVATIONS OF NEUTRON-CAPTURE ELEMENTS IN METAL-POOR HALO STARS In ASP Conf. Ser., The Scientific Impact of the Goddard High-Resolution Spectrograph, ed. J. C. Brandt, T. B. Ake, & C. C. Peterson (San Francisco: ASP), 350 (1998)

1999:

• Current paper in postscript format ``SUPERNOVA BIRTH FOR A BLACK HOLE,'' Nature: News and Views, 401, 124 (September 9, 1999)
• Current paper in postscript format R-PROCESS ABUNDANCES AND CHRONOMETERS IN METAL-POOR STARS ApJ, 521, 194 (1999)

2000:

• Current paper in postscript format NEUTRON CAPTURE NUCLEOSYNTHESIS IN EARLY GALACTIC ENVIRONMENTS in The First Stars, eds. A. Weiss, T. Abel and V. Hill (Berlin: Springer ), 142 (2000)
• Current paper in postscript format EVIDENCE OF MULTIPLE R-PROCESS SITES IN THE EARLY GALAXY: NEW OBSERVATIONS OF CS 22892-052, ApJ, 533, L139 (2000)
• Current paper in postscript format THE R-PROCESS-ENRICHED LOW METALLICITY GIANT HD 115444 ApJ, 530, 783 (2000)
• Current paper in postscript format ABUNDANCES AND AGES IN HALO STARS, in The Tenth Workshop on Nuclear Astrophysics, eds. W. Hillebrandt and E. Muller (Munich: MPI), 64 (2000)
• Current paper in postscript format ON THE SITE OF THE WEAK R-PROCESS COMPONENT, in The Tenth Workshop on Nuclear Astrophysics, eds. W. Hillebrandt and E. Muller (Munich: MPI), 68 (2000)
• Current paper in postscript format NEUTRON CAPTURE ELEMENT ABUNDANCES IN THE GLOBULAR CLUSTER M15, ApJ, 536, L85 (2000)
• Current paper in postscript format NEUTRON-CAPTURE ELEMENTS IN THE EARLY GALAXY: INSIGHTS FROM A LARGE SAMPLE OF METAL-POOR GIANTS, ApJ, 544, 302 (2000)

2001:

• Current paper in postscript format THE AGE OF THE GALAXY FROM THORIUM COSMOCHRONOMETRY, astro-ph/0008185, in The Seventh Texas-Mexico Conference on Astrophysics: Flows, Blows and Glows, Revista Mexicana de Astronomia y Astrofisica, Serie de Conferencias, ed. William Lee and Silvia Torres-Peimbert, 221 (2001)
• Current paper in postscript format NUCLEAR CHRONOMETERS, astro-ph/0101438, in Cosmic Evolution, ed. E. Vangioni-Flam, R. Ferlet and M. Lemoine, (Singapore: World Scientific Publishing), 189 (2001)
• Current paper in postscript format NEUTRON-CAPTURE ELEMENT TRENDS IN THE HALO, astro-ph/0101439, in Cosmic Evolution, ed. E. Vangioni-Flam, R. Ferlet and M. Lemoine, (Singapore: World Scientific Publishing), 179 (2001)
• Current paper in postscript format HALO STAR ABUNDANCES AND R-PROCESS SYNTHESIS, astro-ph/0101440, Nuclear Physics A, 688, 330c (2001)
• Current paper in postscript format THE EARLY FORMATION, EVOLUTION AND AGE OF THE NEUTRON-CAPTURE ELEMENTS IN THE EARLY GALAXY, astro-ph/0103222, in Relativistic Astrophysics: 20th Texas Symposium, eds. C. Wheeler & H. Martel (New York: American Institute of Physics), 337 (2001)
• Current paper in postscript format NEUTRON-CAPTURE ELEMENT ABUNDANCES AND COSMOCHRONOMETRY, astro-ph/0106366, in Astrophysical Ages and Time Scales, eds. T. von Hippel, C. Simpson & N. Manset (San Francisco: ASP), 235, (2001)
• Current paper in postscript format NUCLEOSYNTHESIS CLOCKS AND THE AGE OF THE GALAXY, astro-ph/0109526, in Astrophysical Ages and Time Scales, eds. T. von Hippel, C. Simpson & N. Manset (San Francisco: ASP), 226, (2001)

2002:

• Current paper in postscript format GALACTIC COSMOCHRONOMETRY FROM RADIOACTIVE ELEMENTS IN THE SPECTRA OF VERY OLD METAL-POOR STARS, astro-ph/0109194,Physica Scripta, T100, 15 (2002)
• Current paper in postscript format A SIMPLE MODEL FOR r-PROCESS SCATTER AND HALO EVOLUTION, astro-ph/0103083, ApJ, 575, 845 (2002)
• Current paper in postscript format EUROPIUM ISOTOPIC ABUNDANCES IN VERY METAL-POOR STARS, astro-ph/0201456, ApJ Letters, 566, L25 (2002)
• Current paper in pdf format THE CHEMICAL COMPOSITION AND AGE OF THE METAL-POOR HALO STAR BD +17^\circ 3248, astro-ph/0202429, ApJ, 572, 861 (2002)
• Current paper in postscript format THE R-PROCESS AND CHRONOMETERS, astro-ph/0204294, in The Eleventh Workshop on Nuclear Astrophysics, eds. W. Hillebrandt and E. Muller (Munich: MPI), 176 (2002)
• Current paper in pdf format THORIUM AND URANIUM CHRONOMETERS APPLIED TO CS 31082-001, ApJ, 579, 626 (2002)

BD +17 3248 Recent Results:

Poster and Press Release from Washington AAS Meeting.

2003:

• Pdf version with color figures: The Extremely Metal-Poor, Neutron-Capture Rich Star CS 22892--052: A Comprehensive Abundance Analysis, astro-ph/0303542, Astrophys. J., 591, 936 (2003).

• Pdf version with color figures: Binary Blue Metal-Poor Stars: Evidence for AGB Mass Transfer, astro-ph/0304064, Astrophys. J., 592, 504 (2003).

• Pdf version : Elements of Surprise , Nature: News and Views, 423, 29 (May 4, 2003).

  More papers in 2003:

  2003 Papers

2004:

• Pdf version : Galactic Evolution of Sr, Y and Zr: A Multiplicty of Nucleosynthetic Processes, Astrophys. J., 601, 864, (2004).

• Pdf version : Improved Atomic Data for Ho II and New Holmium Abundances for the Sun and Three Metal-Poor Stars, Astrophys. J., 604, 850 (2004).

• Pdf version : A Sprinkling of Stardust, Nature, 428, 369 (2004).

• Pdf version : Stellar Abundances: The r-Process and Supernovae, in 3-D Signatures in Stellar Explosions, ed. P. Kumar, C. Wheeler & P. Hoeflich (Cambridge: Cambridge Univ. Press), 255 (2004).

• Pdf version : Halo Star Abundances and Heavy Element Nucleosynthesis, astro-ph/0405423, in the Proceedings of the 12th Workshop on Nuclear Astrophysics, eds. E. Muller and H. Thomas Janka (Munich: MPI ), 41 (2004).

• Pdf version : The rise of the s-Process in the Galaxy, ApJ, 617, 1091 (2004).

  2005:

• Pdf version : HST Observations of Heavy Elements in Metal-Poor Galactic Halo Stars, astro-ph/0502591, Astrophys. J., 627, 238 (2005).

• Pdf version : Neutron-Capture Element Abundances in Halo Stars, astro-ph/0409552, in ASP Conf. Ser., Cosmic Abundances as Records of Stellar Evolution and Nucleosynthesis ed. T. Barnes and F. Bash (San Francisco: ASP), 313 (2005).

• Pdf version : Near-UV Observations of CS2947-030: New Constraints on Neutron-Capture Nucleosynthesis Processes, astro-ph/0505002, Astrophys. J., 627, L145 (2005).

• Pdf version : Improved Laboratory Transition Probabilities for Pt I and Application to the Platiunum Abundances of BD +17 3248 and the Sun, Astrophys. J., 619, 639 (2005).

  2006:

• Pdf version : Sm Transition Probabilities and Abundances,'' astro-ph/0510585, Astrophys. J. Supp., 162, 227 (2006).

• Pdf version : Near-UV Observations of HD221170: New Insights into the Nature of r-Process-Rich Stars, astro-ph/0604180, Astrophys. J., 645, 613 (2006).

• Pdf version : Nucleosynthesis: Stellar and Solar Abundances and Atomic Data, astro-ph/0605137, in the Proceedings of the NASA Laboratory Astrophysics Workshop (2006).

• Pdf version : Gd Transition Probabilities and Abundances, astro-ph/0609487, Astrohys. J. Supp., 167, 292 (2006).

• Pdf version : In Memory of Al Cameron, arXiv:astro-ph/0611824, http://indico.cern.ch/conferenceTimeTable.py?confId=059, in Nuclei in the Cosmos-IX, 205 (2006)

• Pdf version : r-Process Enhanced Halo Stars, arXiv:astro-ph/0610412, http://indico.cern.ch/conferenceTimeTable. py?confId=059, in Nuclei in the Cosmos-IX, 14 (2006)

  2007:

• Pdf version : Hf Transition Probabilities and Abundances, astro-ph/0611036, Astrophys. J. Supp., 169, 120 (2007).

• Pdf version : Explorations of the r-Processes: Comparisons between Calculations and Observations of Low-Metallicity Stars, astro-ph/0703091, Astrophys. J., 662, 39 (2007).

• Pdf version : Nucleosynthesis in the Early Galaxy, Astrophys. J., 671, 1685 (2007).

  2008:

• Pdf version : Abundance Signatures in Halo Stars, in First Stars III (2008)

• Pdf version : Nucleosynthesis Modes in the High-Entropy-Wind Scenario of Type II Supernovae, in First Stars III (2008)

• Pdf version : Europium, Samarium, and Neodymium Isotopic Fractions in Metal-Poor Stars, in First Stars III (2008)

• Pdf version : Europium, Samarium and Neodymium Isotopic Fractions in Metal-Poor Stars, astro-ph/0712.2473, Astrophys. J., 675, 723 (2008).

• Pdf version : The Hobby-Eberly Telescope "Chemical Abundances of Stars in the Halo" (CASH) Project. I. The Lithium-, s-, and r-Enhanced Metal-Poor Giant HKII 17435-00532, arXiv:0802.3701, Astrophys. J., 679, 1549 (2008).

• Pdf version : Er II Transition Probabilities and Abundances arXiv:0804.4465, Astrophys. J. Supp., in press (2008).

  Recent Reviews, Essays and Journal Article Reviews:

• Postscript manuscript with color figures: Probing the Neutron-Capture Nucleosynthesis History of the Early Galaxy astro-ph/0209308, PASP, 114, 1293 (2002).

• Pdf journal version with black and white figures: Probing the Neutron-Capture Nucleosynthesis History of the Early Galaxy astro-ph/0209308, PASP, 114, 1293 (2002).

• Pdf manuscript with color figures: The Genesis of the Heaviest Elements in the Milky Way Galaxy Science, 299, 70 (2003).

• Pdf manuscript with color figures: Advances in r-Process Nucleosynthesis in Carnegie Observatories Astrophysics Series, Vol. 4: Origin and Evolution of the Elements, ed. A. McWilliam & M. Rauch (Cambridge: Cambridge Univ. Press), 27 (2004)

• Pdf manuscript with color figures: R-Process Nucleosynthesis in Supernovae Physics Today, Volume 57 Number 10, 47 (October, 2004). Copyright (2004) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. Website link to Physics Today

• Pdf manuscript with color figures: Heavy Element Synthesis in the Oldest Stars and the Early Universe Nature, Volume 440, 1151 (April 27, 2006). This article may be downloaded for personal use only. Any other use requires prior permission of the author and Nature Publishing Group. Website link to Nature

• Pdf article: Journal Club: An astronomer invites you to contemplate the history of the some of the oldest stars in the Universe. Nature, Volume 440, 129 (January 11, 2007). This article may be downloaded for personal use only. Any other use requires prior permission of the author and Nature Publishing Group. Website link to Nature

• Pdf article: Essay in Concepts: A Constant Surprise Nature, Volume 448, 29 (July 5, 2007). This article may be downloaded for personal use only. Any other use requires prior permission of the author and Nature Publishing Group. Website link to Nature

Astro-ph preprint link:

• Website link to astro-ph preprints

ADS link:

• Most of my publications as listed on ADS

Recent Meetings:

Germany 2004 (Ringberg Castle and Munich):

Nuclear Astrophysics 12: ``Halo Star Abundances and Heavy Element Nucleosynthesis''

People at Ringberg

Places at Ringberg

People and Places in Munich

SEATTLE (INT) 2004, 2006 (Institute for Nuclear Theory, Univ. of Washington, Seattle):

STAN Meeting 2004 :

The dinner pics

The talk at STAN

FIRST STARS AND THE EVOLUTION OF THE UNIVERSE Meeting 2006 :

On campus pics

The talk at First Stars and the Evolution of the Universe

VISTARS 2005, 2006 (Russbach, Austria):

VISTARS 2005 pics:

JC and FKT hard at work

More Vistars pics:

People and places at Russbach

A trip to Saltzburg, Austria:

People and places in Saltzburg

A trip to FKT's farmhouse, France:

People and places

VISTARS 2006 pics:

People and places at Russbach

Nuclei in the Cosmos IX (Geneva, Switzerland):

NIC 2006 pics:

People and Places

FRANZ 2007 (Karlsruhe and Frankfurt, Germany):

FRANZ and GERMANY pics:

People and Places

Talk at the FRANZ meeting -- PDF version of power point talk: ``Neutron Capture Elements in Ultra-Metal-Poor Stars,''

Recontres de Blois 2007: MATTER AND ENERGY IN THE UNIVERSE: FROM NUCLEOSYNTHESIS TO COSMOLOGY (Blois, France ):

Blois and France pics:

People and Places

Talk at the blois meeting -- PDF version of power point talk: ``The r-Process in Halo Stars,''

First Stars III - 2007 (Santa Fe, NM):

Poster at First Stars III -- PDF version : ``Abundance Signatures in Halo Stars: Clues to Nucleosynthesis in the First Stars,''

Recent Talks:

• Pdf version of power point talk: ``Probing the Nucleosynthesis Producst of the First Stars,'' Meeting on the Chemical Enrichment of the Early Universe, Santa Fe, NM (2004).

• Pdf version of power point talk: ``Stellar Abundance Observations and the R-Process,'' JINA Workshop on the Discussion of the R-Process, Notre Dame, IN (2005).

• Working hard at the JINA meeting:

• Pdf version of power point talk: ``R-Process Signatures in Halo Stars, '' 2nd Vistars Workshop, Russbach, Austria (2005).

• Pdf version of power point talk: ``Stellar Abundance Observations and Heavy Element Formation, '' AAS Meeting, Minneapolis, MN (2005).

• Pdf version of power point talk: ``The Age of the Oldest Stars as a Constraint on Cosmological Models,'' Meeting on Outstanding Questions for the Standard Cosmological Model, London, England (2007).

  Recent Video Interview with the OU Daily:

• ``Five Minutes with Dr. Cowan - A Star is Born ''

  Figures and Transparencies:

• Color Figure in postscript format Figure 2 from Sneden et al. (2000)
• Color Figure in postcript format  Total Abundances in CS 22892-052
• Color Figure in postcript format  New Total Abundance Figure:
• Color Figure in postscript format  r-Process Abundances in Halo Stars
• Color Figure in postcript format  r-Process Abundances in BD+17 3248
• Color Figure in postscript format  r-Process Abundances in BD+17 3248 With Model SS Fit
• Color Figure in postscript format  Solar System Isotopic Breakdown after Cowan & Thielemann 2004, Physics Today
• Color Figure in jpeg format  Solar System Isotopic Breakdown after Cowan & Thielemann 2004, Physics Today
• Color Figure in postscript format  Chart of the Nuclides after Sneden & Cowan 2003, Science (with thanks to Peter Moeller)
• Color Figure in jpeg format  Chart of the Nuclides after Sneden & Cowan 2003, Science (with thanks to Peter Moeller)

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Internet 2 :

We show in the following images how we are using the capabilities of the Internet 2.
In particular we are accessing  large amounts of
astronomical data that require high-speed transmission.

1. The first image shows actual stellar spectra taken with the Hubble Space Telescope, HST. (The data are transmitted from the satellite to the computers at the Space Telescope Science Institute and then sent over the Internet 2 to our computers here at OU.) The spectral lines are in the ultraviolet portion of the spectra and are not visible on the ground - only space telescopes, like the HST are capable of such observations. These observations are the first to ever detect gold (Au) in old stars, thousands of light years from earth.

HST SPECTRA OF STARS IN THE GALACTIC HALO

2. Abundance observations - note elements such as Barium (Ba), Europium (Eu), and the radioactive element Thorium (Th) - of the star CS 22892-052, which is one of the oldest stars in the universe and located approximately 6,000 light years away. The observations were obtained using both ground-based (Keck and McDonald) and Space-Based (HST) Telescopes:

ABUNDANCES IN CS 22892--052, ONE OF THE OLDEST STARS IN THE UNIVERSE

Images of galaxies taken with the Radio Telescopes  of the Very Large Array (VLA) near Socorro, New Mexico:

3.  Galaxy NGC 7331,  located approximately 30 million light years away,  appears to contain a
Massive Black Hole. This black hole was detected by researchers here at OU (see ``Discovery of a Nuclear X-ray
Source in NGC 7331:'')    A GALAXY WITH A MASSIVE BLACK HOLE -- A GALAXY WITH A MASSIVE BLACK HOLE (jpeg format)

4. Galaxy M83, located approximately 20 million light years away, contains a number of exploding stars
known as supernovae. These include supernovae 1957D, 1950B and 1923A still radiating in the radio,
and detected by OU researchers, almost 80 years after it exploded.
  A GALAXY WITH A NUMBER OF SUPERNOVAE OR EXPLODING STARS

X-Ray Images of External Galaxies:

An XMM image of a massive black hole in an AGN

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Biographical Information:


MY RESEARCH INTERESTS: A BRIEF DESCRIPTION

CURRICULUM VITA: PUBLICATIONS, ETC.

MY ACTIVITIES AT THE UNIVERSITY OF OKLAHOMA: TEACHING, ADVISING, ETC.

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Astronomical Data:


Radio FITS DATA 6 CM FITS file for G25.5.

Radio FITS DATA 20 CM FITS file for M83.

Radio FITS DATA 20 CM FITS file for NGC 7331.

Radio FITS DATA 6 CM FITS file for NGC 7331.

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Assorted Pictures:

London (2007) at the Conference on Outstanding Questions for the Standard Cosmological Model

The boys at CES in Vegas (Venetian)

Linda's trip to South Africa

Linda's trip to Bellagio

Linda's trip to Bellagio in 2006

Linda's trip to Burkina Faso

Linda's trip to Mexico

Winter in Norman

Mom and Meg and Family pictures

Carmen Pantoja and JC at the Washington AAS meeting in January of 2006

Birthday Celebrations

Last Updated 06/20/08

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