Notes

Talk: Extragalactic B-fields from Gamma Rays

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Speaker: Tom Weisgarber (Chicago)
  • Voids: <1nG; filaments: ~0.3 µG; galaxies: ~1 µG; clusters: 10 µG.  No detections of B-fields in voids.
  • Gamma rays interact with the extragalactic background light (EBL) and create electron-positron pairs, which then cascade down to create more gamma rays. This cascade is then observed with some opening angle.  Pair production and inverse Compton … Continue Reading ››
News

New members and computer update

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We have four new members to our group, starting in the Spring semester.  Chao Shi, a second-year graduate student, will be focusing on black hole growth from both stellar-sized and massive seeds.  Three undergraduate students, Erin Caldwell, Vasiliy Demchenko, and Martin Halicek, will be joining the group, obtaining valuable experience in astrophysics research and learning … Continue Reading ››
Notes

JSI Dwarf Galaxy Conference (Day 3)

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Annapolis, Maryland Joe Silk, "DM Annihilations as a Probe of CDM Substructure"
  • Proposing to use the Sun as a WIMP detector above 4 GeV (less massive ones are evaporated).
  • If WIMPs are low-mass (5-10 GeV) and trapped, they will lower the central temperature of the Sun.
  • Energetic neutrinos from WIMPs trapped in the Sun?  Detectable by AMANDA or IceCube?
  • Sommerfeld effect: boosting … Continue Reading ››
Notes

JSI Dwarf Galaxy Conference (Day 2)

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Annapolis, Maryland – Today's talks focus on dwarf galaxy formation Volker Bromm (UT-Austin), "The First Stars and Galaxies"
  • Discussed Clark+ (2010), Greif+ (2011) simulations, looking at disk fragmentation in the case without radiation feedback.  Points to a flat IMF.
  • Stacy+ (2011) included proto-stellar radiative feedback and found that the final mass was 30-40 Msun in a binary.  Hosogawa+ … Continue Reading ››