NOAO Annual Report for FY06
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Appendix A NOAO SCIENTIFIC STAFF: FY06 ACCOMPLISHMENTS AND FY07 PLANS ¬New appointment in FY06 S Non-NSF (external) funding ±Term ended in FY06 HELMUT A. ABT, Emeritus Astronomer Research Interests Formation and evolution of double stars; publication statistics FY06 Accomplishments: Abt considered the eccentricities of 553 spectroscopic and 616 visual binaries with known orbital elements and dwarf primaries. These show that for long periods (P>275 yrs), all eccentricities are equally probable, indicating that when wide binaries are formed, no single eccentricity is preferred. For shorter periods due to tidal interactions, the highest eccentricities disappear first until, for the shortest periods, only the zeros remain. Abt also considered the papers published in the major journals in five sciences (physics, astronomy, geophysics, mathematics, and chemistry). The numbers of papers published annually since 1970 divided by the numbers of members of the appropriate scientific society (e.g. American Physical Society) are constants, indicating that the numbers of scientific papers depend only on the numbers of research scientists and not upon the quality, sensitivity, or quantity of the instruments and computers that they used. Abt presented talks in China on “Early Chinese Inventions” and “National Astronomical Productivities” at Nanjing University and the Purple Mountain Observatory in Nanjing; “Stellar Disks and the Interstellar Medium” at National Astronomical Observatory, Beijing; “Early Chinese Inventions” at Beijing Normal Univ. Beijing. Abt attended the Seventh Pacific Rim Conference on Stellar Astrophysics in Seoul, South Korea, in November 2005, and gave talks on “The First Six Pacific Rim Conferences” and “Tidal Effects in Binaries.” He attended the Centennial Celebration for Dorrit Hoffleit at Yale Univ. in April 2006, and gave a talk on “Spectral Classification Surveys.” Abt attended the IAU General Assembly in Prague, Czech Republic, and IAU Symposium No. 240 on “Binary Stars as Critical Tools and Tests in Contemporary Astrophysics,” and gave a talk on “Observed Orbital Eccentricities.” Abt wrote eight papers. FY07 Plans Abt will attend, by invitation, a conference on “Astronomical Communication” in Brussels, Belgium, June 10-13, 2007, and give a paper. He has a tentative invitation to give several talks in China. Abt will do research on binaries among high-velocity stars, on metallic-line (Am) Stars, and on publication statistics. TAFT E. ARMANDROFF, Astronomer (Director, NOAO Gemini Science Center)± JASON P. AUFDENBERG, Research AssociateS± Research Interests Stellar atmospheres; stellar winds; fundamental properties of stars; interferometry; spectroscopy; radiative transfer; modeling FY06 Accomplishments Aufdenberg and colleagues (including S. Ridgway) published their interferometric observations and modeling of the important photometric standard Vega. This work supports the model of Vega as a pole- on rapid rotator. In addition, Aufdenberg was a co-author on three published interferometric studies based on data from the CHARA Array on Mount Wilson: the detection of Vega’s debris disk in the K- band, measurements of M-dwarf angular diameters, and the detection of circumstellar material surrounding delta Cephei and Polaris. Aufdenberg was also a co-author of a study on the limb darkening A-1 NOAO ANNUAL REPORT FY 2006 of the star SV Cam based on a comparison of model atmospheres to precise multi-band photometry from the Hubble Space Telescope. Aufdenberg also contributed models for a published multi-wavelength study of the prototypical symbiotic star Z And. This work puts forth a new, two-stage model for the symbiotic outburst. Aufdenberg collected additional interferometric data on hot stars Rigel and Spica and presented the first results on Spica as an invited talk in a symposium at the International Astronomical Union General Assembly in Prague. Aufdenberg left the NOAO staff in early August 2006. He is now an assistant professor in the Physical Sciences Department at Embry-Riddle Aeronautical University in Daytona Beach, FL. DMITRY BIZYAEV, Research AssociateS Research Interests High-resolution stellar spectroscopy; stellar radial velocities and chemical abundance; star formation in collisional ring galaxies; structure of spiral galaxies; dark halos FY06 Accomplishments Bizyaev and V.V. Smith continued selection of radial velocity stable red giants for the SIM Planet Quest mission (under NASA grant through JPL). During 121 nights (96 observing ones) at the 82–inch telescope (McDonald Observatory, Texas), 2490 spectra were obtained and all spectra were reduced. Parameters and history of star formation in collisional ring galaxy Arp 10 were studied via the modeling of emission and absorption spectral features (in collaboration with the UWO, Canada; SAO RAS, Russia). Development of the bending instability in galactic disks was studied (in collaboration with Volgograd Univ., Russia). Structural parameters of 140 edge-on galaxies, including extinction-free disk thickness, were estimated from 2MASS NIR images. FY07 Plans Bizyaev will continue the observations of SIM reference stars. He and V.V. Smith expect to estimate radial velocity variation and abundances [Fe/H] for most objects from their sample (about 1400 stars). Studies of propagating star formation in collisional ring galaxies will be continued. Connection between dark halos and stellar disks properties will be studied with the help of edge-on spiral galaxies. ROBERT BLUM, Associate Astronomer, NOAO/NGSC Research Interests The Galactic Center; massive star formation; resolved stellar populations FY06 Accomplishments Blum, in collaboration with PI Meixner (STScI) and colleagues, continued as lead of the evolved stars group (one of three science groups) on the Spitzer Space Telescope SAGE survey. This second generation Legacy program surveyed the LMC in all IRAC and MIPS bands. Two papers were accepted in refereed journals of which Blum was lead author on one. Blum is funding postdoc. Sean Points at CTIO through a sizable Spitzer grant related to the SAGE project (with Co-I Olsen of CTIO). Blum continued his collaboration with Conti (JILA) and Damineli (U. Sao Paulo) to investigate Galactic Giant HII regions with a five-night run on the CTIO 4-m. Blum participated in first science use of the new integral field spectrometer, NIFS, at Gemini North as a member of PI McGregor’s (ANU) NIFS science team. FY07 Plans Blum will continue exploiting the SAGE data set. His evolved star group should produce several more papers this year including a first author for postdoc. Points on the properties of LMC clusters as seen A-2 NOAO SCIENTIFIC STAFF: FY06 ACCOMPLISHMENTS AND FY07 PLANS through SAGE. Blum will continue the program to investigate Galactic Giant HII region stellar content. His group’s ninth paper in this effort is nearly ready to be submitted (lead author Lys Figueredo, a former student of Damineli and now at Open University in the UK). This program seeks to understand massive star formation and Galactic structure and uses the NOAO 4-meters and both Gemini 8-meter telescopes. Blum is reducing a NIFS data set on two Galactic Giant HII regions taken during the 2006 PI time of McGregor at Gemini North. This data set will result in a first author paper for Blum this year. TODD BOROSON Astronomer (Deputy Director, NOAO) Research Interests Structural and physical properties of active galactic nuclei; stellar populations and their evolution; O/IR instrumentation; analysis and mining of large astronomical data sets FY06 Accomplishments Boroson continued to work on reduction of the Gemini IR spectra of QSOs obtained in the previous year. For the automatic measurement of QSO spectral properties, he has developed tools that utilize K-L transforms to produce relatively noise-free versions of the many thousands of SDSS QSO spectra. A number of new correlations among spectral properties are seen in the resulting database. In addition, in collaboration with D. Schneider and M. Eracleous (Penn State U.), he has begun a study of possible binary black hole AGN, in which the H-beta line peak is offset from the systemic velocity by thousands of km/s. FY07 Plans Boroson plans a 6-month sabbatical in FY07, during which he will use the automatic tools developed in the past year to complete the analysis of the low-redshift SDSS QSO spectra and interpret the observed characteristics in terms of physical parameters. Spectra of the sample of possible binary black hole AGN will be analyzed in search of evidence that the offset H-beta peaks are shifting. KATHERINE J. BRAND, Research Associate± SEAN D. BRITTAIN, Research Associate (Michelson Fellow, NASA)± CHRISTINE CHEN, Research Associate (Spitzer Fellow, NASA)S Research Interests Star and planet formation FY06 Accomplishments Chen, in collaboration with the IRS Disks team (led by D. Watson, University of Rochester), modeled Spitzer IRS 5–35-micron spectra of ~60 nearby IRAS-discovered debris disks. She assumed that circumstellar dust was either located in (1) a ring around the star, or (2) a continuous disk that is produced as particles spiral into the central star under the Poynting-Robertson effect. Chen found that the spectra are better fit by a single temperature black body, suggesting that the inner regions of the disks have been cleared and that the disks are collisionally dominated. In collaboration with A. Li and the Fab4 team (led by K. Stapelfeldt, JPL), Chen modeled the Spitzer IRS 5–35-micron spectrum of beta Pictoris. She reported: (1) the first detection of weak crystalline silicate emission features at wavelengths lambda > 20 microns, (2) upper limits on the atomic and molecular gas masses, and (3) that photon-stimulated desorption may produce the observed atomic Na I gas seen in Keplerian rotation. A-3 NOAO ANNUAL REPORT FY 2006 FY07 Plans Chen hopes to continue to study the dust and gas around young stars in Sco-Cen. In collaboration with M. Jura (UCLA), she hopes to complete a Spitzer MIPS search for 24- and 70-micron excesses around 100 solar-like stars in ScoCen, and, in collaboration with the IRS Disks team, to use Spitzer IRS and MIPS SED mode observations to follow up discoveries of debris disks.