APRIL 28 - MAY 2, 2008
MONDAY, APRIL 28
3:00 pm: Joint CfA/MIT Supernova Remnants and Neutron Stars Seminar. "Winds, Bubbles and Supernovae - Tracing the Effects of Massive Stars on their Surroundings," Vikram Dwarkadas, University of Chicago. Phillips Auditorium.
Abstract: As a massive star (> 8 solar masses) evolves, it tends to lose a large amount of mass through winds and outbursts. This material accumulates around the star, forming circumstellar wind-blown "bubbles." The mass-loss rate of the stellar wind, and its velocity, will vary continuously during the various phases of the star's evolution. This gives rise to a complicated circumstellar structure, accompanied by the formation and growth of hydrodynamical instabilities, and the onset of turbulence. When the star ends its life in a spectacular supernova (SN) explosion, the resulting shock wave will interact with this altered medium. The further evolution of the shock wave, and the radiative signatures from the system, will depend on the structure of this medium. In this talk we will investigate these scenarios using analytic and numerical calculations. We first discuss the evolution of the medium around a massive star. We then discuss the evolution of the SN shock wave within this medium, and compare and contrast this with existing models of SN evolution. We will study the particular case of a 35 solar mass star and its effect on the ambient medium. Finally, we will apply our results to understanding one of the most fascinating objects ever, and the closest supernova to us in over 300 years, SN 1987A. Space and ground-based observatories have revealed the unusual nature of the rising X-ray and radio lightcurves from SN 1987A, and the optical appearance of bright "hot-spots" on a circular equatorial ring. We will show how our theories can help us to understand the density structure, morphology and emission from this object.
WEDNESDAY, APRIL 30
2:30 pm: Solar, Stellar, and Planetary Sciences Division Seminar. "Advances in Our Helioseismic View of the Sun," Shravan Hanasoge, Stanford University. Pratt Conference Room.
Abstract: In recent decades, imaging of the solar interior has been made possible through the development and application of techniques of helioseismology which combine mathematical rigour and sophisticated guesswork. Analyses of the high quality observations made by the Michelson Doppler Imager (MDI) instrument onboard the Solar and Heliospheric Observatory (SOHO) satellite have led to continuous progress in our ability to infer subtle aspects of the recondite solar interior. This rush of discoveries has brought with it some skepticism and a need to determine whether the diagnostic agents, namely the waves, indeed behave as we expect them to. Towards this goal, modeling wave behavior in the Sun using either numerical or analytical techniques is a useful way to proceed. Numerical methods are developed to simulate 3D linear wave propagation in magnetic and non-magnetic environments in a solar-like stratified medium. Helioseismic analyses of the simulated data have provided us with startling insights into the nature of wave interactions and scattering. A number of results will be discussed.
4:00 pm: Initiative in Innovative Computing (IIC) Seminar. "DNA I/O: Computing Challenges in Reading Personal Genomes and Writing Synthetic Genomes," George Church, Professor of Genetics, Harvard Medical School; Member of the Affiliated Faculty of the Harvard-MIT Division of Health Sciences and Technology. Preceded by refreshments at 3:45 pm. Room 330, 60 Oxford Street, Cambridge. Event parking is available at the 52 Oxford Street Garage [map]. Please inform the parking attendant you are attending the IIC seminar. (The IIC seminar series schedule is updated often with additional information and seminars.)
Abstract: Due to recent technologies, DNA is yet another digital medium for rapid I/O. Rather than asking DNA to compete with silicon VLSI computers on their own turf or vice versa, we are pursuing hybrid systems, harvesting the fruits of natural past evolution or accelerating it in the lab. As the cost of personal genomes drops, how will we accurately obtain and interpret 6 billion base pairs each for 6 billion people?
THURSDAY, MAY 1
11:00 am: Institute for Theory and Computation (ITC) Colloquium. "Galactic Winds," Crystal Martin, University of California, Santa Barbara. Pratt Conference Room.
Abstract: For some time now, we have seen overwhelming evidence that supernovae explosions in starburst galaxies drive significant amounts of metals out of galactic disks. The difficult question has been determining how far away from a galaxy these metals go. I will present new measurements of the size (and size evolution) of metal-enriched regions in the IGM and discuss their relation to starburst winds. I will attempt to synthesize these results with our direct knowledge of the wind dynamics in local starburst galaxies.
12:30 pm: Optical and Infrared Astronomy Division Lunch Talk. "Mapping Mass in the Local Universe," Dr. Karen Masters, CfA. Pratt Conference Room.
Abstract: We only see a small fraction of the matter in the universe, but the rest gives itself away by the impact of its gravity. The amount and distribution of this unseen mass provides information about the basic cosmology of the universe and helps to tell a story about how galaxies, stars and eventually planets were formed. On the largest scales galaxies seem to trace a "cosmic web". Their so-called "peculiar motions" (under the influence of gravity) have painted a picture of an underlying web of unseen mass (or "dark matter"), but previous "peculiar velocity" surveys have struggled to meet their full potential because of the large errors on individual measurements, poor statistics and uneven sky coverage. I am working on a new survey to measure the motions of thousands of galaxies and map the cosmic web with unprecedented detail. This survey makes use of both optical/near infra-red and radio observations of spiral galaxies to measure their distances and peculiar velocities. It will provide significant improvements in sky coverage especially near the obscuring plane of our Galaxy which crosses the poorly understood "great attractor" region towards which the whole local universe appears to be moving. I will give a progress report on the survey including a look at almost 400 hours of neutral hydrogen (21cm) observations from the Green Bank Telescope as well as Southern hemisphere observations with the Parkes Radio Telescope.
1130 am: Visualizing Astronomy at the CfA. "The World Wide Telescope Project," Curtis Wong, Microsoft Research. The purpose of this lecture series is to engage the CfA community in how to best bring astronomical images, data, and concepts to the multitude of interested audiences, which ranges from the scientific community to the media and ultimately the general public. Phillips Auditorium.
4:00 pm: Colloquium. pH Lecture: "Fishing for Planets with HATNet," Dr. Gaspar Bakos, CfA. Preceded by tea at 3:30 pm. Phillips Auditorium.
Abstract: Within planetary science, the first decade of the 21st century is arguably that of transiting extrasolar planets, standing on the shoulders of the very successful radial velocity searches. If we rewind our clocks just ten years, we had scarce information on exoplanets; their masses were incompletely known, and we had no information at all on their radii, chemical composition, or atmospheric characteristics; the related astrophysics was based mainly on theoretical speculation. The situation has changed dramatically, and by now we have a sample of forty transiting planets with most of the above properties well characterized. I will help the audience to glimpse the continuous excitement and surprises provided by the exponential boom in transit numbers. With more transiting planets definite relations and trends are emerging, but this field is still suffering from small number statistics. Thus a number of projects are searching for the elusive transit signatures. One of them, HATNet at the CfA, has contributed quite significantly through finding seven (or more?) planets. I will give some background information on HATNet, describe how we search for planets, and comment on some of our more interesting detections.
8:00 pm: Kids Academy. "Do-It-Yourself Astronomy," Meredith Hughes, CfA. Kids Academy features a fun, interactive program followed by telescopic observing from the observatory roof, if weather permits. Children ages 8 to 13 are welcome to attend. No reservations or tickets are required. Doors open at 7:30 pm. Phillips Auditorium.
Abstract: Here's your chance to practice using binoculars and telescopes to explore the wonders of the night sky. Learn where in the sky to find the jewels of binocular astronomy and the basics of how to use a telescope to navigate through the heavens. Cloudy or clear, get hands-on experience with some of our telescopes, and see for yourself how lenses and mirrors work to make the universe come into focus.
SAO HUMAN RESOURCES NOTES
2008 Pre-Retirement Series for CSRS and FERS Employees
The Greater Boston Federal Executive Board has announced their 2008 Pre-Retirement Series. This year, for the first time, they will offer a 1-full day program for CSRS employees and 1-full day program for FERS employees, both featuring consultant Steve Marder and both will be held at the Volpe Center in Cambridge. The cost is $50 per person and registration is on a first-come first-served basis.
The following links provide details and online registration.
Directions to the Volpe Center are available here.
Training Registration Instructions
Complete the newly simplified Request & Authorization for External Training/Tuition Reimbursement form, obtain the required department/division approvals and send the completed, signed form to the SAO Benefits Office in Human Resources, MS17. Approved participants will then be registered for this training by Procurement. Please note: if you register yourself for this training online, you will be required to provide payment via credit card and you may not receive reimbursement.
The new training form is a fillable Word document. If you should have any questions about completing this form or the enrollment process, please don't hesitate to contact Linda McDonald, ext. 6-7605 (e-mail: lmcdonald@cfa), or Anne LeBlanc, ext. 5-7371 (e-mail: aleblanc@cfa).
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.