NOVEMBER 26 - 30, 2007
MONDAY, NOVEMBER 26
12 noon: Solar, Stellar, and Planetary Sciences Division Seminar. "The Thermal Structure of the Solar Corona," Dr. Enrico Landi, Artep, Inc./Naval Research Laboratory. Pratt Conference Room.
Abstract: The heating of the solar corona, as well as the acceleration of the solar wind, are intimately connected with the thermal structure of the solar corona, i.e. the distribution of coronal plasma with temperature. In this talk I will review 1) the main diagnostic techniques we use to study the thermal structure of the solar corona, and 2) the measurements obtained from the CDS and SUMER spectrometers on board the SOHO satellite. I will use both reviews to discuss the common assumption that the coronal plasma temperature distribution is continuous, and show that such assumption is incorrect. I will present a new picture of the thermal structure of the solar corona based on SOHO measurements, and discuss its implications.
TUESDAY, NOVEMBER 27
2:30 pm: Joint CfA/Tufts/MIT Cosmology Seminar. "Unravelling the Accelerating Universe," Dr. Rachel Bean, Cornell University. Phillips Auditorium.
Abstract: There are a wealth of possible theoretical avenues being explored to explain the recent observations of accelerated expansion in the universe. In this colloquium I'll discuss the current status of some of these theoretical investigations into the nature of dark energy, discussing expected observational implications for matter and gravity based theories and how constraints are being placed on these with current and future data.
WEDNESDAY, NOVEMBER 28
12:30 pm: High Energy Astrophysics Division Lunch Talk. "Cosmological Simulations of Clusters of Galaxies: Status, Problems, Challenges," Dr. Andrey Kravtsov, University of Chicago. Pratt Conference Room.
Abstract: I will describe high-resolution self-consistent cosmological simulations of clusters forming in the concordance Cold Dark Matter model with vacuum energy. The resolution of the simulations is sufficiently high to resolve formation and evolution of cluster galaxies and their impact on cluster gas. We use these simulations to study the effects of galaxy formation on the global properties of clusters, such as the shape of cluster dark matter halo and its density profile, the baryon fractions, gas density and temperature profiles. I will present comparisons of simulations results with the recent X-ray Chandra, Sunyaev-Zeldovich, and optical observations of clusters with highlights of both successes and problems of the models. I will show that despite complexities of their formation and uncertainties in their modeling, clusters of galaxies both in observations and numerical simulations are remarkably regular and consistent outside of their core region (~5% of the virial radius), which holds great promise for their use as cosmological probes.
4:00 pm: Initiative in Innovative Computing (IIC) Seminar. "Parallelism, Distribution, and Scaling On-line Games," Jim Waldo, Distinguished Engineer, Sun Microsystems Labs. 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: This talk will discuss Project Darkstar, a server-side framework for massive multi-player on-line games (MMOs). Darkstar provides a highly concurrent, distributed infrastructure with a programming model that allows the game programmer to write as though he or she was working on a single thread running on a single machine. This can only be done by carefully restricting the programming model; we will discuss the model and how we use that model to hide complexity while giving scalability.
4:30 pm: Joint CfA/Harvard University Atomic Physics Colloquium. "Cooling of Nanoscale Mirrors," Prof. Pierre Meystre, University of Arizona. Preceded by refreshments at 4:00 pm. Room 356, Jefferson Laboratory, Harvard University.
Abstract: The observation of quantum dynamics in truly macroscopic objects appears increasingly feasible as a result of recent experimental advances that include novel cooling techniques and progress in nanofabrication. This is an exciting prospect, as it would enable us to explore the quantum-classical boundary as well as to test quantum mechanics in an entirely new regime. The implementation of characteristically quantum mechanical phenomena at a macroscopic scale also promises technological benefits for areas from quantum measurement to the interferometric detection of gravitational waves and to atomic force microscopy. A promising route to these objectives is through the use of optomechanical systems, particularly optical cavities where the support of one of the mirrors is a nanoscale cantilever. The talk will review recent developments in the optical cooling of these moving mirrors and discuss the prospects for reaching their quantum mechanical ground state of vibration. Future directions, including the realization of quantum entanglement in these systems, will also be touched upon.
THURSDAY, NOVEMBER 29
11:00 am: Science Education Seminar and Open Discussion. Weekly sessions focus on current department programs, literature reviews, and recent trends in science education and assessment. Some sessions feature outside speakers or guests. All members of the CfA community are welcome. Please contact Bruce Ward at bward@cfa, if you wish to attend any session. Phillips Auditorium.
11:00 am: Institute for Theory and Computation (ITC) Seminar. "Numerical Simulations as a Cosmological Tool," Volker Springel, Max-Planck-Institute for Astrophysics. Pratt Conference Room.
Abstract: The standard cold dark matter cosmology provides a highly successful paradigm for cosmological structure growth that is in good agreement with a large array of observational data, especially on large scales. However, there are significant challenges to the theory on small scales, for example in the abundance of dark matter substructures, in the central density profiles of halos, and in the small-scale phase-space structure of dark matter. Also, some peculiar objects, e.g. the 'bullet cluster', seem difficult to reconcile with LCDM. In my talk, I will review current results of numerical cosmological simulations with respect to these problems, and motivate the need for precision calculations in the non-linear regime in order to check our theoretical modeling. Finally, I comment on the current level of accuracy reached in cosmological simulations, and on some of the challenges that lie ahead for future work with simulations.
12:30 pm: Optical and Infrared Astronomy Division Lunch Talk. "Galaxy Evolution with the Far Infrared Deep Extragalactic Legacy Survey," Dr. Minh Huynh, IPAC. Pratt Conference Room.
Abstract: The study of LIRGs and ULIRGs is important for understanding galaxy formation and evolution because they contribute the majority of the cosmic IR luminosity budget at high redshifts. Ultra-deep 70 micron imaging can detect LIRGs and ULIRGs out to redshifts of 1 to 2. Preliminary results from the Far Infrared Deep Extragalactic Legacy (FIDEL) survey with the Spitzer Space Telescope will be presented. This is the deepest survey ever made at 70 micron, with a sensitivity of ~0.6 mJy rms achieved in the deepest region, and it will cover roughly 6 times the area of the combined GOODS fields. I will present 70 micron source counts, infrared colours, redshifts and submm counterparts. The luminosity function for infrared galaxies is derived, which shows strong luminosity evolution in LIRGS between 0 < z < 1.
4:00 pm: Colloquium. "The Dirt on Dust Composition: An X-ray Perspective," Prof. Julia Lee, CfA. Preceded by tea at 3:30 pm. Phillips Auditorium.
Abstract: There is a multi-wavelength (radio-IR) industry focused on the problem of astrophysical dust. Yet, despite extensive studies, and good progress, there remains much to understand of dust properties (size, composition, and distribution) in astrophysical environments, from the colder ISM environs to the hotter environments near the disks and envelopes of young stars and compact sources. If nothing else, dust is everywhere, and for many astrophysical topics, its presence hinders our studies in some way, be it to extinguish a UV part of a spectrum, or possibly affect Cosmology results. I will discuss the program we have developed to determine grain composition using combined X-ray laboratory+space efforts. Specifically, I will discuss how we can apply experimental solid state physics techniques to the study of astrophysical dust (as facilitated by Chandra HETGS Composition towards luminous accretion systems in Galactic X-ray binaries and supermassive black holes in extragalactic AGN) to possibly probe grain/molecule types missed by non-X-ray efforts. I will also show our initial results which hint at different dust composition along different lines-of-sight, and in different environments ranging from X-ray binaries (e.g. GRS 1915+105, Cygnus X-1) to dusty AGN (e.g. MCG -6-30-15, IRAS 13349+2438). Together, with Spitzer efforts, we anticipate a unique probe of dust location and properties.
SAO HUMAN RESOURCES NOTES
SI Employee Assistance Program Information Sessions
The SI Employee Assistance Program offers problem-focused counseling and referral services for virtually any personal problem which could affect an individuals work performance. Program staff are also available to provide counseling to management and supervisory staff regarding workplace conflict. The services are available free of charge to all SAO employees.
Steve Neslen of the SI Employee Assistance Program staff will visit SAO on Wednesday, November 28. Information sessions will be conducted at CDP and at 60 Garden Street. Please join Steve to learn about all that the EAP has to offer, as well as how to deal with workplace stress, change management, and how to deal with/prevent workplace and domestic violence.
PLEASE NOTE: There will be a special briefing offered to supervisors, How to Assist Troubled Employees, during the afternoon session.
The schedule for the visit is as follows:
Session I: November 28, 2007, Cambridge Discovery Park, Room 483
Session II: November 28, 2007, Phillips Auditorium, 60 Garden Street
Steve will also be available to provide individual counseling. If you wish to meet with Steve, please contact him ahead of time to make an appointment. Steve may be reached at neslent@si.edu.
Be sure to take advantage of this training opportunity. To learn more about the SI EAP, please refer to http://wohr.si.edu/EAPT/EAPhomeT.htm.
Open Season Reminder
The 2008 Health Benefits Open Season for both Federal and Trust Fund employees is from November 12 to December 10, 2007. During this period, employees eligible for health benefits have an opportunity to enroll in a plan if not currently enrolled, change to a new provider, or make changes to their current coverage. If you do not wish to make changes during this open enrollment period, your current coverage will remain in force through the 2008 health plan year.
In addition, two Flexible Spending Accounts (FSAs) - a Health Care FSA and a Dependent Care FSA - are available for the first time to Trust Fund employees in 2008. For information about these new benefit options, go to the HR Homepage and click on the What's New link.
Plan changes and new enrollments for Federal employees will become effective on January 6, 2008. For Trust Fund employees, 2008 health plan changes and new enrollments will be effective on January 1, 2008.
Please note that Human Resources must receive your plan change forms or new enrollments by close of business on December 10, 2007.
If you have questions or need a health plan brochure, please contact Anne LeBlanc, ext. 5-7371, or Linda McDonald, ext. 6-7605.
Leave Donations Requested
Due to a medical emergency, Joyce Janjigian of the Solar, Stellar and Planetary Science Division has been approved as a leave donor recipient in the Leave Transfer Program. Donna Coletti of the Library is also an approved leave donor recipient. Any SAO Trust Fund employee who wishes to donate annual leave to Joyce and/or Donna should complete a Leave Donor Form and send it to MS 17.
Under the Leave Transfer Program, Trust Fund employees may only donate annual leave to other Trust Fund employees and Federal employees may donate annual leave only to other Federal employees. If you should have any questions or are not able to access the form, please contact Anne LeBlanc, ext. 5-7371.
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.