MARCH 2 - 6, 2015


10:30 am: Atomic and Molecular Physics Division Seminar. "Collisions in Molecular Spectroscopy," Piotr Wcislo, Institute of Physics, Nicolaus Copernicus University. Pratt Conference Room.

Abstract: Ultra-accurate spectroscopic measurements together with appropriate ab initio calculation allows not only to study properties of interaction between molecules in the presence of light, but also to follow interesting dynamics of the molecular gas. Such development is crucial for both optical metrology and fundamental molecular physics studies. Our recent results on an intriguing problem that have remained unsolved for 25 years will be presented. A collisional inhomogeneous broadening of the H2 Q(1) line perturbed by Ar was observed for the first time almost three decades ago. Several attempts were made to explain the line broadening from ab initio calculations, which however resulted in fundamental discrepancies between theory and experiment. Our new approach to this issue properly reconstructs the experimental spectra and shows that the reason of so far discrepancies is completely different from the one suspected in the precedent literature. I will also briefly discuss the physical meaning of the parameters of the Hartmann-Tran profile, which has been recently recommended as a good candidate for H2O spectra analysis and is likely to be adopted as a standard for atmospheric spectra studies.

Noon: Solar, Stellar, and Planetary Sciences Division Seminar. "The Space Photometry Revolution of Asteroseismology and Exoplanets," Dr. Daniel Huber, Sydney Institute for Astronomy. Pratt Conference Room.

Abstract: Asteroseismology - the study of stellar oscillations - is a powerful tool to probe the structure and evolution of stars. In addition to the wealth of newly discovered exoplanets, space-based telescopes such as Kepler have revolutionized asteroseismology by detecting oscillations in thousands of stars from the main sequence to the red-giant branch. In this talk I will highlight the most recent asteroseismic discoveries by Kepler/K2 with a particular focus on exoplanet host stars, and discuss efforts to improve stellar properties of the Kepler parent sample to derive accurate planet occurrence rates. I will also discuss the prospects for asteroseismic studies with TESS, including its role for the synergy of asteroseismology and galactic astronomy to probe the chemo-dynamical evolution of stellar populations in our galaxy (galactic archeology).


1:00 pm: Institute for Theory and Computation (ITC) Pizza Lunch. Speakers: Drs. Lorenzo Sironi and Nick Murphy, CfA. Topics: To be announced. Phillips Auditorium.


4:30 pm: Joint ITAMP/HQOC Quantum Sciences Seminar. "Merging Metamaterials with Quantum Photonics," Vladimir Shalaev, Purdue University. Tea served at 4:00 after short student talk. Jefferson 250, Department of Physics, Harvard University.


11:00 am: Institute for Theory and Computation (ITC) Colloquium. "Magnetars Life Cycle: Birth, Evolution and Death," Dr. Nanda Rea, CSIC-IEEC. Pratt Conference Room.

Abstract: Magnetars are the strongest magnets we know of, and show themselves via powerful X/gamma-ray steady and flaring emission. The energetics of such flares in our Galaxy second only the supernova explosions. In this talk I will first review the observational characteristics of these highly magnetic pulsars, and some recent discoveries in the field. Subsequently, I will present what we currently know about their life-cycle, through detailed simulations of neutron star magneto-thermal evolution and pulsar population synthesis. I will then finish with some considerations on how the study of the Galactic population of magnetars might constrain their possible connection with Gamma Ray Bursts.

4:00 pm: Colloquium. "Magnetism Matters," Dr. Sarah Gibson, National Center for Atmospheric Research/High Altitude Observatory. Preceded by tea at 3:30 pm. Phillips Auditorium.

Abstract: Magnetism defines the complex and dynamic solar corona. Twists and tangles in coronal magnetic fields build up energy and ultimately erupt, hurling plasma into interplanetary space. These coronal mass ejections (CMEs) are transient riders on the ever-outflowing solar wind, which itself possesses a three-dimensional morphology shaped by the global coronal magnetic field. Coronal magnetism is thus at the heart of any understanding of space weather at the Earth. I will describe the current state of the art in coronal magnetometry, and present results from the Coronal Multichannel Polarimeter (CoMP) at Mauna Loa Solar Observatory (MLSO), which since 2011 has taken polarimetric observations of the solar corona in the near-infrared on a near-daily basis. I will discuss work in progress that utilizes forward modeling to synthesize polarimetric data at multiple heights and vantage points, and at wavelengths from radio to infrared to visible to ultraviolet. The goal is to use such synthetic testbeds to determine the ideal set of observations for constraining the coronal magnetic field, and to establish a Data-Optimized Coronal Field Model (DOC-FM) that efficiently incorporates these data into global magnetic models. This work will provide essential tools and motivation for the planning and implementation of future coronal polarimetric projects and missions spanning a broad range of wavelengths.


The CfA will be hosting the 26th International Symposium on Space Terahertz Technology, March 16-18, 2015, at the Knafel Center in the Radcliffe Yard on the Harvard University campus. Additional information can be found here.