1. Igor V. Moskalenko Stanford University on behalf of the Fermi LAT Collaboration and the Fermi mission RESULTS FROM THE FIRST MONTHS OF THE FERMI GAMMA-RAY SPACE TELESCOPE MISSION

2. gamma rays provide a direct view into Nature’s largest accelerators (neutron stars, black holes) gamma rays provide a direct view into Nature’s largest accelerators (neutron stars, black holes) gamma rays probe cosmological distances gamma rays probe cosmological distances (e.g.,  +  EBL  e + + e - ) (e.g.,  +  EBL  e + + e - ) huge leap in key capabilities, including a largely unexplored energy range; great potential for discovery: e.g. dark matter huge leap in key capabilities, including a largely unexplored energy range; great potential for discovery: e.g. dark matter Twoinstruments: Large Area Telescope (LAT), 20 MeV - >300 GeV Two instruments: Large Area Telescope (LAT), 20 MeV - >300 GeV Gamma-ray Burst Monitor (GBM), 10 keV - 25 MeV Gamma-ray Burst Monitor (GBM), 10 keV - 25 MeV LAT GBM

3. GLAST renamed Fermi by NASA on August 26, 2008 http://fermi.gsfc.nasa.gov/ “ Enrico Fermi (1901-1954) was an Italian physicist who immigrated to the United States. He was the first to suggest a viable mechanism for astrophysical particle acceleration. This work is the foundation for our understanding of many types of sources to be studied by the Fermi Gamma-ray Space Telescope, formerly known as GLAST. ” DoE – NASA – international partnership

4. Year 1 Science Operations Timeline Overview L AUNCH L +60 days week week week week month 12 m o n t h s spacecraft turn-on checkout LAT, GBM turn-on check out “first light” whole sky initial tuning/calibrations pointed + sky survey tuning Start Year 1 Science Ops Start Year 2 Science Ops in-depth instrument studies sky survey + ~weekly GRB repoints + extraordinary TOOs Release Flaring and Monitored Source Info GBM and LAT GRB Alerts continuous release of new photon data Observatoryrenaming GI Cycle 1 Funds Release Fellows Year 1 Start LAT 6-month high-confidence source release, GSSC science tools advance release GI Cycle 2 Proposals LAT Year 1 photon data release PLUS LAT Year 1 Catalog and Diffuse Model 2ndSymposium June 11, 2008 August 12, 2009

5. > 2000 AGNs blazars and radiogal = f( ,z) evolution z < 5 Sag A* 10-50GRB/year 10-50 GRB/year GeV afterglow spectra to high energy Cosmic rays and clouds acceleration in Supernova remnants OB associations propagation (Milky Way, M31, LMC, SMC) Interstellar mass tracers in galaxies Possibilities starburst galaxies galaxy clusters measure EBL unIDs Dark Matter neutralino lines sub-halo clumps  -ray binaries Pulsar winds  -quasar jets Pulsars emission from radio and X-ray pulsars blind searches for new Gemingas magnetospheric physics pulsar wind nebulae 20 MeV - > 300 GeV CR electrons 20 GeV – a few TeV

6. LAT images the sky one photon at a time:  -ray converts in LAT to an electron and a positron ; direction and energy of these particles tell us the direction and energy of the photon GBM

7.  France  IN2P3, CEA/Saclay  Italy  INFN, ASI, INAF  Japan  Hiroshima University  ISAS/JAXA  RIKEN  Tokyo Institute of Technology  Sweden  Royal Institute of Technology (KTH)  Stockholm University  United States  Stanford University (SLAC and HEPL/Physics)  University of California at Santa Cruz - Santa Cruz Institute for Particle Physics  Goddard Space Flight Center  Naval Research Laboratory  Sonoma State University  Ohio State University  University of Washington Principal Investigator: Peter Michelson (Stanford University) ~270 Members (~90 Affiliated Scientists, 37 Postdocs, and 48 Graduate Students) construction managed by Stanford Linear Accelerator Center (SLAC), Stanford University

8. …. Transient class Source class Diffuse class multiple scattering dominates Finite pitch of Si strips

9. Years Ang. Res. (100 MeV) Ang. Res. (10 GeV) Eng. Rng. (GeV) A eff Ω (cm 2 sr) #  -rays EGRET1991–005.8°0.5°0.03–10750 1.4 × 10 6 /yr AGILE2007–4.7°0.2°0.03–501,500 4 × 10 6 /yr Fermi LAT 2008–3.5°0.1°0.02–30025,0001 × 10 8 /yr AGILE (ASI) EGRET Fermi / LAT LAT has already surpassed EGRET and AGILE celestial gamma-ray totals Unlike EGRET and AGILE, LAT is an effective All-Sky Monitor whole sky every ~3 hours CGRO EGRET

12. June 11, 2008 12:05 pm (EDT)

14. GLAST Large Area Telescope GLAST First Light Seminar, 26 Aug 2008 14

17. 205 sources - based on first 3 months of sky-survey arXiv:0902.1340v1 [astro-ph.HE] 8 Feb 2009

18. 205 Preliminary LAT Bright Sources Census of Associations (not Identifications) ClassNumber Radio/X-ray pulsar 15 LAT pulsar 14 Globular cluster (pulsars?) 1 HMXB2 LMC1 Flat Spectrum Radio Quasars 62 Bl Lac Objects 46 Blazar, uncertain type 11 Radio galaxies 2 Special cases (under study) 14 Unassociated37

19. EGRET pulsars young pulsars discovered using radio ephemeris pulsars discovered in blind search 33 gamma-ray and radio pulsars (including nine ms psrs) 16 gamma-ray only pulsars High-confidence detections through 2/28/2009 millisecond pulsars discovered using radio ephemeris Pulses at 1/10 th real rate

20. LAT has reported 6 high-energy bursts since launch LAT has reported 6 high-energy bursts since launch long-duration bursts First detection of short-duration burst at high energy Z = 4.35 ± 0.15

21.  For the first time, can study time structure > tens of MeV.  Feature in the LC: — pulse in interval “a” disappears at LAT energies. Science Express, 19 Feb 2009, pg 1 For this burst,  absorption arguments provide a stringent lower limit of  min = 860

22. August 3 – October 30, 2008

23. July 1 – Sept 24, 2008

24. August 3 – August 7, 2008

25. EGRET observations showed excess emission > 1 GeV when compared with conventional model tuned to reproduce local cosmic-ray nuclei and electron spectra Variety of explanations Variations in cosmic-ray spectra over Galaxy Unresolved sources (pulsars, SNRs, …) Dark matter Instrumental ~100% discrepancy > 1 GeV

26.  Spectra shown for mid-latitude range → EGRET GeV excess in this region of the sky is not confirmed  Sources are not subtracted but are a minor component  LAT errors are systematics dominated and estimated ~10% → this is preliminary  Work to analyse and understand diffuse emission over the entire sky is in progress

27. 27 ► origin is a mystery; either sources there for Fermi to resolve (and study!) OR there is a truly diffuse flux from the early Universe EGRET constrains blazars to be > 25% of diffuse; annihilation of cosmological neutralinos has, in principle, a distinctive spectral signature LAT baseline background limit Energy (keV) E 2 dJ/dE (keV/(cm2-s-keV-sr) EGRET steep- spectrum quasars Seyfert II galaxies Seyfert I galaxies Type 1a Supernovae discovery space blazars normal galaxies cluster mergers primordial diffuse new physics EGRET

28.  Fermi LAT is expected to detect ~10 7 electrons/yr above 20 GeV, 4×10 5 electrons/yr above 100 GeV, and ~2,500 electrons/yr above 500 GeV assuming a steep power law electron spectrum with power index -3.3.  Energy range ~20 GeV--2 TeV  Features associated with local CR sources (pulsars, SNRs)  Diffuse emission & CR propagation  IC scattering in the heliosphere Stay tuned! CR electron spectrum will be released on May 2 (APS meeting)

29.  Fermi Gamma-ray Space Telescope fully operational..  In first few days of sky survey, the LAT corroborated many of the great discoveries of EGRET; now finding new sources as well;  With 3 months of the 1 st year all-sky survey phase;  large number of pulsars detected, some only in  -rays;  many flaring active galaxies observed; about half not seen by EGRET;  Flaring sources observed along the galactic plane;  High-energy emission seen from 3 GRBs; first time seen from short-duration burst;  Quiescent sun detected at high energies;  Major progress in understanding galactic diffuse emission  With time, Fermi will probe deeper and deeper into the high-energy Universe