FEBRUARY 8 - 12, 2010

TUESDAY, FEBRUARY 9

11:00 am: Atomic and Molecular Physics Division Informal Seminar. "Atomic Data of Heavy Elements for Magnetically Confined Fusion Plasma Studies, Dr. Adam Foster, CfA. Phillips Auditorium.

Abstract: Radiation from impurities in magnetically confined fusion devices is regularly utilized on existing tokamaks for both diagnostic purposes (to reveal plasma conditions) and to estimate the impurity content itself to detect any detrimentally high radiation power losses. For the light elements (Z < 18) commonly found in tokamaks the atomic physics infrastructure to allow such observations and model the results is well developed. The proposed design for ITER calls for a partially tungsten divertor. This has led to a resurgence of interest in the behavior of heavy impurities in plasma. Many codes for generating fundamental atomic data and for modeling plasma behavior encounter significant difficulties when dealing with heavy elements. I will describe methods developed and employed during my work for the ADAS group during my PhD to enable the generation of a baseline quality of data for all ions of all heavy elements, and subsequent data reduction techniques to allow this to be used in MHD modeling of fusion plasmas. I will also briefly outline my current work on the AtomDB/APED/APEC suite here at the CfA.

2:30 pm: MIT/CfA/Tufts Cosmology Seminar. "Galaxy Formation under the Halo Occupation Ansatz," Jeremy Tinker, University of California, Berkeley. Phillips Auditorium.

Abstract: Spatial clustering provides a window into galaxy formation and evolution that is not often looked through. The halo model of bias provides a method to create a mapping between galaxy properties and dark matter halo properties that can provide telling insights and tests of galaxy formation models. In my talk I will use color- dependent galaxy clustering out to redshift z less than 2 to constrain the processes by which galaxies cease their star formation and enter the red sequence. In the local universe, I will probe the relationship between halos and galaxies directly through group catalogs created from DR7 of the SDSS. These catalogs provide strong tests of the halo model ansatz and demonstrate that correlations between star formation and environment can be almost fully explained by the correlations between star formation and halo mass.

WEDNESDAY, FEBRUARY 10

12:30 pm: High Energy Astrophysics Division Lunch Talk. "The Solar Moreton wave of 6 December 2006: Evidence for a CME Driver," Dr. Ed Cliver, Hanscom Air Force Base. Pratt Conference Room.

Abstract: We analyzed ground- and space-based observations of the eruptive flare (3B/X6.5) and associated Moreton wave (~850 km/s, ~270 degree azimuthal span) of 6 December 2006 to determine the wave driver - either flare pressure pulse or coronal mass ejection (CME). While the Moreton wave observations themselves are excellent, there are key gaps in coronagraph and EIT/SXR coverage. Thus kinematic arguments cannot rule out either a flare or CME origin, although they are less constraining for the CME scenario. Support for a CME driver is based primarily on the correspondence between wave evolution and the inferred eruption of a coronal arcade overlying a region of weak magnetic field to the west of the principal flare. -alpha footpoint brightenings, disturbance contours in off-band images, and He I 10830 flare ribbons are used to trace the development of the eruption from 18:42-18:45 UT as it moved southwest along the arcade. At 18:45 UT, the Moreton wave exhibited two separate arcs, one off each flank of the tip of the arcade, that merged and coalesced by 18:47 UT to form a single smooth wave front having its maximum amplitude in the direction of the arcade central axis. We suggest that the erupting arcade (i.e., CME) expanded laterally to drive the coronal shock responsible for the Moreton wave. We attribute a darkening in H-alpha from a region underlying the arcade to absorption by faint unresolved post-eruption loops.

4:30 pm: Joint CfA/Harvard University Atomic Physics Colloquium. ""Few-Body Physics with Ultracold Atoms," Dr. Selim Jochim, Max Planck Institute for Nuclear Physics. Preceded by tea at 4:00 pm. Room 356, Jefferson Laboratory, Harvard University.

Abstract: During the past years, ultracold atoms have been a fantastic playground to study few-body physics in the universal regime, in which the properties of bound states do not depend on particular details of the interatomic potential, but only on a few numbers, such as the scattering length. The major ingredient in current experiments is the tunabilty of the scattering length using an externally applied magnetic field using Feshbach resonances. In 2003, this allowed the creation of diatomic Feshbach-molecules, which have been an important starting point for many important milestones, such as the realization of the BEC-BCS crossover, or the controlled preparation of ultracold ground state molecules. Associated with every universal two-body bound state is an infinite series of three-body bound states, as was predicted in 1970 by Vitaly Efimov. Such Efimov states have first been observed in 2006 with ultracold bosonic Cs atoms in the form of three-body scattering resonances. More recently, our group has found evidence for universal three-body bound states between three distinguishable fermionic 6Lithium atoms. Such a three-component system offers the possibility to study many body physics which because of its SU(3)-symmetry could resemble the simplest models of QCD.

THURSDAY, FEBRUARY 11

11:00 am: Institute for Theory and Computation (ITC) Colloquium. "Characterizing Exoplanet Atmospheres: Modeling the Transmission Spectrum of Transiting Planets Large and Small," Jonathan Fortney, University of California, Santa Cruz. Pratt Conference Room.

4:00 pm: Colloquium. "Images and Spectra of an Extrasolar Planetary System," Dr. Bruce Macintosh, Lawrence Livermore National Laboratory. (Anyone wishing to meet with the speaker should contact the host, Ruth Murray-Clay, ext. 5-7184.) Preceded by tea at 3:30 pm. Phillips Auditorium.

Abstract: Although more than 400 extrasolar planets are now known, almost all have been detected indirectly - through radial velocity measurements or eclipses of their parent star. Direct detection - spatially resolving the planet from the star - opens up new areas of exoplanet phase space and new avenues for planet characterization. It is also extremely challenging, since a mature Jupiter-like planet is 10^9 times fainter than its host star. The promise of this approach was recently demonstrated with HST images of a planet orbiting Fomalhaut and adaptive optics images of a three-planet system orbiting the young A star HR8799. I will discuss the HR8799 system in detail, including photometry, properties of the host star, astrometry and orbital stability. We have also now obtained a spectrum of the outermost planet in the system - the coolest exoplanet ever studied spectroscopically - and these are showing an atmosphere very different from a brown dwarf. The HR8799 planets were detectable because they are extremely young (60 Myr) and massive (5-10 Jupiter masses.) To next major step in direct detection will be dedicated instruments such as the Gemini Planet Imager (GPI). GPI will use a 4000-actuator MEMS deformable mirror, an advanced coronagraph, and nanometer-precision wavefront sensing to achieve contrasts 1-2 orders of magnitude better than any current ground or space facility. I will briefly discuss the design and scientific capabilities of GPI, which is planned to have first light in 2011 on the Gemini South 8-m telescope.

FRIDAY, FEBRUARY 12

12 noon: Optical and Infrared Astronomy Division Lunch Talk. "Lessons Learned from the Balloon-borne Large Aperture Submillimeter Telescope, BLAST," Marco Viero, University of Toronto. Phillips Auditorium.

Abstract: BLAST was a balloon-born pathfinder for the SPIRE instrument on the Herschel space observatory. Its successful 2006 flight produced numerous Galactic and extragalactic scientific results, albeit after two years of often difficult analyses. I will focus on selected extragalactic results, and the lessons learned in preparation for similar analyses with Herschel.

12:30 pm: Radio and Geoastronomy Division Lunch Talk. "Disks and Binaries: Studying Intermediate and Massive Star Formation at Small Angular Scales," Hugh Wheelwright, University of Leeds. Room M-340, 160 Concord Ave.

Abstract: Massive stars play a fundamental role in many areas of astrophysics. However, despite their importance, the process by which massive stars form is still not certain. Intermediate mass, Pre Main Sequence stars (Herbig Ae/Be stars) offer an insight. Most reside in binary systems,and as these objects are young their binary properties are imprints of the star formation process. I will present a spectro-astrometric studyof Herbig Ae/Be stars and discuss their binary properties, which suggest that these systems form via disk fragmentation. This has been proposed for massive stars, although we still lack a detection of asmall scale disk around a massive young stellar object. Indirect evidence of such disks is provided by CO first overtone bandhead emission. I will present the largest velocity resolved spectraldata-set around CO for this type of object. Modeling indicates thatthe line profiles can indeed be attributed to disks. Milli-arcsecond precision, velocity-resolved spectro-astrometry of this emission willbe presented, and discussed with reference to the properties obtained via modeling. Finally, I will present a study of Be stars. It has long been known that Be stars are surrounded by equatorial disks, but the formation mechanism of these disks is still unknown. To understand how such disks form it is important to determine their kinematics. I will present sub milli-arcsecond precision spectro-astrometry of Be star disks, which directly constrains their kinematical structure.

2:00 pm: Special Talk. "Globular Clusters and their Galaxies," Dr. Jay Strader, CfA. Phillips Auditorium.

Abstract: Globular clusters are fossils of star formation at all epochs. I will discuss how new photometric and spectroscopic surveys of globular cluster systems are providing important constraints on the formation of early-type galaxies, stellar halos, and the distribution of dark matter in the local universe. In addition, observations of individual clusters in nearby galaxies are turning up unexpected wrinkles, with potentially far-reaching implications for stellar populations.

SAO HUMAN RESOURCES NOTES

Trust Fund Leave Donations Needed

Meredith Wills-Davey, a Trust Fund employee of the High Energy Astrophysics Division, has been approved as a leave recipient under the Leave Transfer Program. Any Trust employee wishing to donate their annual leave to Meredith during her medical emergency may do so by completing a leave donor form. Please send your completed form to Linda McDonald at MS 17. Leave Transfer Program details can be accessed at http://www.cfa.harvard.edu/hr/handbook/leaves.html. Please note that Trust Fund employees may donate annual leave only to other Trust employees. Federal employees may only donate annual leave to other Federal employees.

Federal Leave Donations Needed

Julius Cesar Lopez, a Federal employee at the Whipple Observatory, has been approved as a leave recipient under the Leave Transfer Program. Any Federal employee wishing to donate their annual leave to Cesar during his medical emergency may do so by completing a leave donor form. Please send your completed form to Linda McDonald at MS 17. Leave Transfer Program details can be accessed at http://www.cfa.harvard.edu/hr/handbook/leaves.html. Please note that Federal employees may donate annual leave only to other Federal employees. Trust employees may only donate annual leave to other Trust employees.

Job Vacancies

An online listing of all current SAO job openings is available. For more information, please call Human Resources, ext. 5-7371, or view your nearest bulletin board.

The Calendar is prepared by the Web Services Group. Entries may be submitted via email to weekly_cal@cfa.