Weekly Calendar of Events

APRIL 20 - 24, 2015


Noon: Solar, Stellar, and Planetary Sciences Division Seminar. "Non-Relativistic and Relativistic Turbulent Reconnection," Prof. Alex Lazarian, University of Wisconsin, Madison. Pratt Conference Room.

Abstract: I shall discuss how the turbulence controls reconnection rates and what is the relation of turbulent reconnection to other reconnection mechanisms. I shall discuss non-relativistic, relativistic reconnection as well as the process of generating of turbulence by turbulence itself. The latter process of self-generated turbulence is of particular interest for different astrophysical phenomena including solar flares, gamma ray bursts etc.

2:00 pm: Special Seminar. "Carrington-L5: The Next Generation Space Weather Operational Mission," Markos Trichas, Airbus Defence and Space, UK. Pratt Conference Room.

Abstract: Airbus Defence and Space have carried out a study to investigate the possibilities for an operational L5 space weather mission, in collaboration with RAL, the UK Met Office, UCL and Imperial College London. The study looked at the user requirements for an operational mission, a model instrument payload, and a mission/spacecraft concept. A particular focus is cost effectiveness and timelineness of the data, suitable for operational forecasting needs. The study focused on a mission at L5 assuming that a US mission to L1 will already occur, on the basis that L5 offers the greatest benefit for SWE predictions. The baseline payload has been selected to address all MOSWOC/SWPC priorities using UK/US instruments, consisting of: a heliospheric imager, coronagraph, EUV imager, magnetograph, magnetometer, solar wind analyser and radiation monitor. The platform is based on extensive re-use from Airbus' past missions to minimize the cost and a Falcon-9 launcher has been selected on the same basis. A schedule analysis shows that the earliest launch could occur in 2020, assuming Phase A KO in 2015. The study team have selected the name "Carrington" for the mission, reflecting the UK's proud history in this domain.


1:00 pm: Institute for Theory and Computation (ITC) Pizza Lunch. "Magnetic Star - Disk Interactions," Prof. Dong Lai, Cornell University, and "Cosmic Ray Acceleration and Propagation in the Presence of Turbulence," Prof. Alex Lazarian, University of Wisconsin, Madison. Phillips Auditorium.


12:30 pm: High Energy Astrophysics Division Lunch Talk. 1) "Wavefront Sensing in the Adjustable X-ray Optics Program," Dr. Ryan Allured, CfA; 2) "Progress in Mapping the Milky Way," Dr. Mark Reid, CfA. Phillips Auditorium.

Abstract: 1) The SMART-X mission concept is a large area, high resolution X-ray observatory promising to usher in the next era of X-ray astronomy. Piezoelectrically adjustable X-ray optics (AXRO) represent a critical technology for the realization of such a mission. The AXRO groups at SAO and Penn State have fabricated and tested both flat and cylindrical piezoelectrically adjustable prototypes. A crucial step in the evaluation of these prototypes has been the development of wavefront sensing metrology for measurement of mirror figure and adjuster influence functions. Full mirror figure measurements and influence functions have been measured on flat prototypes. More recently, a cylindrical metrology system has been developed for the evaluation of Wolter-I optics. I will overview the AXRO concept, recent WFS metrology results, and plans for the future. 2) The BeSSeL Survey uses the VLBA to measure trigonometric parallaxes to hundreds of star forming regions across large portions of the Milky Way. I will show the latest results on tracing spiral structure and estimates of the distance to the Galactic Center and the rotation speed of the Milky Way.

1:00 pm: Institute for Theory and Computation (ITC) Seminar. "Spin Chaos in Hot Jupiter Formation and Planets Around Shrinking Binaries," Prof. Dong Lai, Cornell University, and "High-Energy Emission from Pulsar-Aided Supernovae," Dr. Kohta Murase, Penn State. Pratt Conference Room.


11:00 am: Institute for Theory and Computation (ITC) Colloquium. "The New Magellanic Dwarfs," Dr. Vasily Belokurov, Institute of Astronomy, Cambridge. Pratt Conference Room.

4:00 pm: Colloquium. Clay Lecture: "Gas Flows and Galaxy Evolution: The Wake of the Giants," Dr. Kate Rubin, CfA. Preceded by tea at 3:30 pm. Phillips Auditorium.

Abstract: The environments extending several hundred kiloparsecs from galaxies contain the fuel that feeds galactic star formation, and act as the reservoir into which ejecta from stellar and AGN feedback are driven. Observations of the cool hydrogen and metal content, kinematics, and morphology in these regions (i.e., the circumgalactic medium, or CGM) can therefore provide incisive tests of our understanding of these processes. Focusing at z~2, I will discuss current constraints on the content and kinematic coherence of the CGM around galaxies spanning a broad range of luminosities, including both vigorously star-forming objects and low-mass, sub-L* systems. These measurements reveal a substantial mass in metals in these environments, comparable to the metal mass contained in stellar and interstellar material at the same epoch, and significantly higher than is predicted in state-of-the-art cosmological simulations. This widespread distribution of metals is suggestive of efficient enrichment processes occurring at much earlier times, for example via highly mass-loaded winds from galaxies at z > 3. These observations pose a challenge to current models of stellar feedback in the early Universe.

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


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