MARCH 10 - 14, 2008

MONDAY, MARCH 10

12 noon: Solar, Stellar, and Planetary Sciences Division Seminar. "Monitor: Rotation Periods of Low-Mass Stars in Young Open Clusters," Dr. Jonathan Irwin, CfA. Pratt Conference Room.

Abstract: The rotation rate of a star is one of the few fundamental stellar properties which is directly accessible observationally, by measuring photometric periods. I summarise results from rotation period measurements for F-M stars in a range of clusters spanning ages of ~1 Myr to 250 Myr, including data from the literature, and a sample of new periods from the Monitor project, a large-scale time-domain photometric survey of young open clusters and star-forming regions. The results confirm a strong mass-dependence of the rotational period distributions also seen in v sin i measurements, which appears to persist from the youngest ages in the sample to the zero age main sequence, evolving in a manner which can be approximately reproduced by simple models of rotational evolution. The origin of this mass-dependence is still not clear however. Finally, I summarise prospects for future work in this area, highlighting the lack of measurements for mid to late M-dwarfs at intermediate ages (~500 Myr), which are important for constraining the evolution at the low-mass end.

3:00 pm: Joint CfA/MIT Supernova Remnants and Neutron Stars Seminar. "Chandra Observation of the Mixed-Morphology Remnant Kes 27 & Chandra Observations of Magellanic Cloud Remnants," Dr. Fred Seward, CfA. Pratt Conference Room.

Abstract: Chandra observed Kes 27 and found a unique double-shell structure. There are also many internal unresolved sources. Diffuse emission is interpreted in terms of reflection of a shock from a cavity wall. Upper limits are calculated for internal neutron stars. Chandra has also observed 30 remnants in the Magellanic Clouds. Images and spectra may be inspected at http://hea-www.harvard.edu/ChandraSNR/. Time remaining after any discussion of Kes 27 will be used to show general characteristics derived from this data set.

TUESDAY, MARCH 11

2:00 pm: Special Talk. "CMB Polarimetry and the Search for Inflationary Gravitational Waves," Dr. John Kovac, California Institute of Technology. Phillips Auditorium.

Abstract: Inflation predicts a cosmic gravitational-wave background (CGB), the amplitude of which measures the Inflationary energy scale. The CGB in turn produces a faint but unique signature in the B-mode polarization of the CMB at angular scales between 4 and 2 degrees. Many simple models of Inflation predict the CGB at levels r ~ 0.01 to 0.1. At these levels, the Inflationary B-mode signal should be within experimental reach, leading the 2005 Task Force on CMB Research to identify this search as the number one priority for the field. BICEP, the first CMB polarimeter specifically designed for this search, began operating at South Pole Station in early 2006. BICEP is mapping 2% of the sky that is uniquely free of Galactic confusion. It should reach sensitivity to r 0.1 during 2008, and with planned upgrades should approach r ~ 0.01 in 2011. A sister experiment, QUAD, is pushing the limits of CMB polarimetry at smaller angular scales where measurements of B-modes from lensing promise a sensitive probe of the Dark Energy equation of state, the sum of neutrino masses, and improved constraints on Inflation.

WEDNESDAY, MARCH 12

4:00 pm: Initiative in Innovative Computing (IIC) Seminar. "Making the Sky Searchable," David Hogg, Associate Professor, Department of Physics, New York University. 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: For the purposes of (a) restoring the meta-data of archived astronomical imaging data, (b) adding meta-data to amateur data and thereby bringing them into the professional domain, (c) relieving hardware and software projects from demanding astrometric requirements, and (d) making life better for observers, we have created a web service that automatically calibrates astronomical image coordinate systems. This system makes use only of the information in the image pixels, and needs no prior information about image pointing, rotation, or plate scale. I will demo the system, describe how it works, and summarize future plans for implementation, enhancement, and scientific discovery.

THURSDAY, MARCH 13

11:00 am: Institute for Theory and Computation (ITC) Colloquium. Speaker: Peter Goldreich, School of Natural Sciences, Institute for Advanced Study. Topic: To be announced. Pratt Conference Room.

12:30 pm: Optical and Infrared Astronomy Division Lunch Talk. "Toward a Homogeneous Set of Transiting Planet Parameters," Dr. Willie Torres, CfA. Pratt Conference Room.

Abstract: With 30 transiting exoplanets now known, the time is ripe to seek patterns and correlations among their observed properties, which may give important insights into planet formation, structure, and evolution. This task is made difficult by the widely different methodologies that have been applied in individual cases to measure the planet parameters, which makes the sample inhomogeneous. Furthermore, in many systems our knowledge of the planet properties is limited by the knowledge of the properties of the parent stars. We have undertaken the first comprehensive analysis of the data for all transiting planets using a uniform methodology. I describe this work, along with several correlations that have emerged recently from these data.

4:00 pm: Colloquium. "Alien Communications: Scientists and Science Reporting," Dan Vergano, USA Today; and Nieman Fellow, Harvard. (Anyone wishing to meet with the speaker should contact the host, Dr. Margaret Geller, 5-7409.) Preceded by tea at 3:30 pm. Phillips Auditorium.

FRIDAY, MARCH 14

11:00 am: Special Talk. "Clustering, Quenching and Feedback: Galaxies and AGN at z=1," Dr. Alison Coil, Steward Observatory, University of Arizona. Phillips Auditorium.

Abstract: Roughly half of the red elliptical galaxies observed today have formed since z=1. I will present galaxy clustering results from the DEEP2 Redshift Survey that strongly constrain the mechanism responsible for the quenching or cessation of star formation in these galaxies. I will show where this quenching is occurring on large scales and how it can not be due primarily to cluster-specific physics. I will also present results on the clustering of optically-bright quasars and X- ray selected AGN and show how AGN accretion correlates with the star formation activity in galaxies at z=1. I will also show new results on the prevalence of outflowing galactic winds at z=1 and discuss their role in quenching star formation. Finally, I will present a new wide-area prism survey that will allow further studies of galaxy evolution to z=1 with the largest faint galaxy survey to date.

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