Events Calendar

JSI Colloquium - Shawhan, Christe, and Zhang
Monday 05 December 2016, 15:30 - 16:30
Contact Susan Lehr
Location Room 1136 Physical Sciences Complex

Speakers: Peter Shawhan (UMD), Steven Christe (NASA/GSFC), and Will Zhang (NASA/GSFC) 
Date:  Monday, December 5th, 2016
Time: 3:30 PM - 4:30 PM (Refreshments @ 3:00 pm)
Location:  Physical Sciences Complex Room 1136, University of Maryland, College Park

This month’s JSI colloquium will feature three short talks on new mission concepts being proposed to recent and upcoming NASA SMEX, MoO, and MidEx mission opportunities that involve members of JSI.  Please join us in learning about the instruments, mission concepts, and their science menus.

"TAO-ISS: a Transient Astronomy Observatory with a Focus on X-rays”
Peter Shawhan (UMD Physics)
We present the design of a mission with new capabilities for time-domain astronomy in the X-ray band.  The primary instrument is a Wide-Field Imager (WFI) which uses a "lobster-eye" microchannel plate to focus soft X-rays, achieving good sensitivity with a field of view of nearly 400 square degrees.  This is supplemented by a Gamma-ray Transient Monitor (GTM) to detect gamma-ray bursts over much of the sky.  With a 3-axis pointing system and an active control link, the WFI is capable of responding promptly to triggers from the GTM and/or external triggers.  This will provide exciting capabilities for rapidly following up LIGO/Virgo event candidates as well as surveying and studying other astrophysical transients in the soft X-ray band.

"The Focusing Optics X-ray Solar Imager Small Explorer Mission”
Steven Christe (GSFC Heliophysics)

FOXSI, the first ever solar-dedicated, direct-imaging, hard X-ray (HXR) telescope, detects hot plasma and energetic electrons in and near energy release sites in the solar corona via bremsstrahlung emission, measuring both spatial structure and particle energy distributions. FOXSI provides two orders of magnitude faster imaging spectroscopy than previously available, probing physically relevant timescales (1s) never before accessible. These observations address fundamental questions of energy release and efficient particle acceleration that have importance far beyond their solar application (e.g., planetary magnetospheres, flaring stars, accretion disks). FOXSI will measure not only the bright X ray emission where electrons lose most of their energy at chromospheric footpoints, but also simultaneous emissio from electrons as they are accelerated in the corona and propagate along magnetic field lines. FOXSI detects emission from high in the tenuous corona, where previous instruments have been blinded by nearby bright features. Consequently, for the first time, FOXSI fully characterizes the accelerated electrons and hottest plasmas as they evolve in energy, space, and time. With its low background and high sensitivity, FOXSI tests models proposed to explain the puzzle of coronal heating by detecting the X-ray emission from hot plasma and accelerated electrons in quiescent or non-flaring active regions that is considered to be the “smoking gun” of coronal heating by small, unresolvable, impulsive heating events (nanoflares).  FOXSI makes hard X-ray observations in the photon energy range 5–50 keV with high spatial and spectral resolution, supported by soft X-ray (1–15 keV) observations with high spectral resolution, to address fundamental science goals from the NASA Heliophysics Roadmap. An instrument concept like FOXSI was recommended by the Heliophysics Decadal Survey as part of the SEE 2020 mission.  FOXSI's new observations, using proven technology, enables revolutionary advancements over the pioneering work of the Ramaty High Energy Solar Spectrographic Imager (RHESSI) by surpassing the limitations of indirect Fourier-transform imaging. FOXSI's use of direct imaging provides orders-of-magnitude improvement in dynamic range and sensitivity by focusing X-rays over large collecting areas onto small pixelated detectors with low background. The Nuclear Spectroscopic Telescope Array (NuSTAR) mission has already demonstrated the power of direct HXR imaging for astrophysics, and FOXSI builds on NuSTAR's few capability-limited observations of the Sun Unlike NuSTAR, FOXSI can handle fluxes over 8 orders of magnitude including from large X-class flares, and has the angular resolution required to separate coronal and chromospheric sources in solar flares. FOXSI is the culmination of a series of successful projects and missions. High-resolution focusing optics flew on the FOXSI-1 and -2 sounding rockets in 2012 and 2014, after earlier development on five flights of the High Energy Replicated Optics (HERO).

"The Survey and Time-domain Astrophysical Explorer (STAR-X)"
Will Zhang (GSFC Astrophysics)
STAR-X is an X-ray telescope with the following characteristics: (1) large field of view; (2) excellent uniform PSF in the entire FOV; and (3) large effective area. STAR-X will catch and study transients, including those resulting from mergers of compact objects, supernova explosions, tidal disruptions, and gamma ray bursts. STAR-X will also conduct surveys to study the growth of compact objects, including stellar mass black holes in the Milky Way and nearby galaxies as well as distant, high-redshift supermassive black holes. The capabilities of STAR-X also enable the study of hot, low surface brightness diffuse emission from galaxy clusters and supernova remnants. STAR-X is facilitated by a spacecraft bus capable of autonomous and fast slewing to targets of opportunity.

Parking:  You may park in the Regents Drive Parking Garage located directly across from the Physical Sciences Complex.  All Pay Station Parking is now located on the top floor of the garage.  Look for the green signs and park in any numbered lot.  Please use parking code 883-95508 for this event.  This parking code is good for 12/05/16 only.

Suggestions for colloquium speakers are welcome.  Please contact the JSI Colloquium committee:  This email address is being protected from spambots. You need JavaScript enabled to view it. (NASA/GSFC)  /  This email address is being protected from spambots. You need JavaScript enabled to view it. (UMD Astronomy)  /  This email address is being protected from spambots. You need JavaScript enabled to view it. (UMD Physics)