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Fermi Large Area Telescope Year One Highlights

Fermi Large Area Telescope Year One Highlights. Ronaldo Bellazzini (INFN-Pisa) ronaldo.bellazzini@pi.infn.it Rappresentante nazionale INFN collaborazione Fermi. Riunione Commissione Scientifica Nazionale II INFN Roma, 1 ottobre 2009. initial tuning/calibrations.

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Fermi Large Area Telescope Year One Highlights

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  1. Fermi Large Area TelescopeYear One Highlights Ronaldo Bellazzini (INFN-Pisa) ronaldo.bellazzini@pi.infn.it Rappresentante nazionale INFN collaborazione Fermi Riunione Commissione Scientifica Nazionale II INFN Roma, 1 ottobre 2009

  2. initial tuning/calibrations in-depth instrument studies Release Flaring and Monitored Source Info GBM and LAT GRB Alerts Year 1 Science Operations Timeline Overview August 12, 2009 Start Year 1 Science Ops Start Year 2 Science Ops “first light” whole sky LAT, GBM turn-on check out Observatory renaming spacecraft turn-on checkout sky survey + ~weekly GRB repoints + extraordinary TOOs pointed + sky survey tuning week week week week month 12 m o n t h s LAUNCH L+60 days 2nd Symposium June 11, 2008 1st LAT Catalog 25 august 2009 continuous release of new photon data LAT 6-month high-confidence source release GSSC science tools advance release LAT Year 1 photon data release PLUS Diffuse Model

  3. Smooth Sailing Under Remarkable Skies • Since LAT Activation on 24 June, 2008 • Over 70,000,000,000 hardware triggers • Over 13,000,000,000 events sent to the ground • Over 50,000,000,000,000 bits written to the SSR

  4. Fermi LAT Data Processing • Total events • > 13B evts processed • ~200M photon candidates • Daily rates • 15 GB raw data • 750 GB after recon • 10Kjobs • Processing time • 1-3 hours processing - GRB and flare detections, spectral analysis plus science routine analysis automated (ASP + RSP) • 8 hours (peak) for tinal photon list at FSSC

  5. LAT subsystems response stability CAL Low Energy Trigger threshold - 100 MeV TKR Single Hit efficiency >> 98% (req) CAL High Energy trigger threshold – 1 GeV TKR Strip Noise Occupancy << 10-4 (req)

  6. Detector Stability • We have run the “Routine Calibrations” twice now • December 2008 and June 2009 • No changes to onboard configuration as a result of most recent calibration runs • TKR noise is stable • CAL and ACD pedestals and gains are stable • Last TKR hot strip configuration change was in April 2009 • 325 total strips are disabled • We launched with 201 strips disabled • Two CAL Log Accept Thresholds have been disabled • February and June 2009 • Only one log-end each, so the logs are not lost • The details are being studied by the CAL team

  7. ~64 papers in Year 1 INFN CA in 26% of them

  8. Science impact by citation • “Measurement of the Cosmic Ray e++e- Spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope” (05/2009) • Cited across a broad range - cosmic-ray, astronomy, particle physics (D0, BABAR) • “Fermi/Large Area Telescope Bright Gamma-Ray Source List” (07/2009) • “Fermi Observations of High-Energy Gamma-Ray Emission from GRB 080916C” (03/2009) • “Bright Active Galactic Nuclei Source List from the First Three Months of the Fermi Large Area Telescope All-Sky Survey” (07/2009) • “The Fermi Gamma-Ray Space Telescope Discovers the Pulsar in the Young Galactic Supernova Remnant CTA 1” (11/2008) ~141 ~60 ~50 ~40 ~25

  9. NASA’s Fermi Explores High-energy Space Invaders

  10. Fermi-LAT Cosmic-Ray Electron Spectrum The APS published a total of about 18000 papers last year, but only around 100 Viewpoints will appear each year. This places your paper in an elite subset of our very best papers Gene D. Sprouse, Editor in Chief

  11. Some possible interpretations • Several papers already published to explain electron spectrum • Together with other observations (positron fraction, diffuse g-ray) Dark Matter Pulsars Grasso et al. 2009 Source stocasticity Strumia et al. 2009 Secondary CR acc. Blasi 2009 Grasso et al. 2009

  12. Citations history for PRL102.181101.2009 ~ > 1/day average > 60% related to DM scenarios

  13. NASA’s Fermi telescope reveals best-ever view of the gamma-ray sky 11-3-2009 5 top sources within our Galaxy • the quiet sun (moving in the map) • LSI +61 303 - a high-mass X-ray binary • PSR J1836+5925 – a gamma-ray-only pulsar • 47 Tucanae – a globular cluster of stars • unidentified, new and variable, 0FGL J1813.5-1248 5 top sources beyond our Galaxy • NGC 1275 – the Perseus A galaxy • 3C 454.3 – a wildly flaring blazar • PKS 1502+106 – a flaring 10.1 billion ly away blazar • PKS 0727-115 – a quasar • unidentified known, 0FGL J0614.3-3330

  14. LAT High Confidence Bright Source list 3 months LAT data – 206 sources with > 10 s significance only 60 associated with EGRET sources – variability! Year 1 catalog in preparation  >1000 sources ! 2009, ApJS, 183, 46 arXiv:0902.1340v1 [astro-ph.HE] 8 Feb 2009

  15. NASA's Fermi Telescope Probes Dozens of Pulsars 9 months map in background • Science, 322, 1218, 2008 – Fermi discovery of the first g-ray only pulsar in the SNR CTA1 • Science, 325, 845, 2009 – Fermi detection of 16 g-ray only pulsar • Science, 325, 845, 2009 – A population of ms g-ray pulsars seen with Fermi • Science, 325, 845, 2009 – Fermi detection of high energy g-ray emission in 47 Tuc • Several ApJ papers on specific meaningful pulsars (Vela, J20210, J1028 ….) + PSR catalog

  16. Spectral measurements and emission models • Evidence of g-ray emission in the outer magnetopshere due to absence of super-exponential cutoff • Radio and g-ray fan beams separated • g-ray only PSRs Vela Abdo, A. A. et al. 2009, ApJ, 696, 1084 PSR J2021+3651 ApJ, 700, 1059 arXiv:0905.4400

  17. Fermi Sees Most Extreme Gamma-ray Blast Yet The first burst to be seen in high-res by the Fermi telescope had the greatest total energy, the fastest motions and the highest-energy emissions ever seen Large fluence (2.4×10-4erg/cm2) & redshift (z=4.35±0.15) • record breaking • Eγ,iso ≈ 8.8×1054 erg ≈ 4.9 Mc2 • Γmin≈ 890 ± 20 • MQG > 1.5 x 1018 (GeV) 19-2-2009 located at 12B light years from us using observations of optical afterglow by the GROND observatory

  18. GRB 080916C - Highlights • For the first time, can study time structure > tens of MeV, 14 events above 1 GeV • First low-energy GBM peak is not observed at LAT energies • z = 4.35 +/0.15 8 keV – 260 keV 260 keV – 5 MeV • High energy emission delayed • The bulk of the emission of the 2nd peak is moving toward later times as the energy increases • Clear signature of spectral evolution • Eγ,iso ≈ 8.8×1054 erg ≈ 4.9 Mc2 • Γmin≈ 890 ± 20 • MQG > 1.5 x 1018 (GeV) LAT raw LAT > 100 MeV LAT > 1 GeV T0 Science 323, 1688 (2009)

  19. GRB 090510 – Highlights • LAT emission delayed • Spectral evolution • High energy emission starts at 2° GBM peak • > 1GeV emission starts at 4° GBM peak • Highest energy photon (31 GeV) located on 6° GBM peak • Clear power law spectral component at high energy  deviation from Band function • Powerful outflow • GLorentz ≈ 1000 • Lorentz InVariance test • MQG > several Mplanck ArXiv 0908.1832, submitted to Nature

  20. Fermi GRBs through June 2009 GRB 080825C GRB 080916C – bright, long, z=4.35 GRB 081024B – short GRB 081215A – LAT rate increase GRB 090217 GRB 090323 – ARR, z=3.6 GRB 090328 – ARR, z=0.736 GRB 090510 – short, intense, z=0.903 GRB 090629 GRB 090902B – bright, long, highest photon energy ever at 33 GeV GRB090926 – long, high energy, z=2.106 10 LAT-detected high-energy bursts + 1 last friday

  21. GRB 090902B observation sequence • 11:05:15 UT – GBM GCN alert notice – ARR triggered • 15:05 UT – GBM human-in-the-loop localization • LAT datamon and processing • 14:44 UT – GRB is seen in the telemetry • 18:24 UT – data ingest • 19:54 UT – GRB is seen in datamon plots • 20:59:48 UT – FT1 file available • ASP results ~20 min later, human-in-the-loop localization • Swift ToO request issued at ~21:30 UT, begins at 23:36 UT (12.5 hr after the GBM trigger)‏ • 21:19:03 UT – 1st GBM circular (GCN 9866)‏ • 22:48:18 UT – 1st LAT circular (GCN 9867)‏ • (RA,Dec=265.00, 27.33) with a 90% containment radius of 0.06 deg (statistical; 68% containment radius: 0.04 deg, preliminary systematic error is less than 0.1 deg) • 03:00:57 UT – Swift/XRT afterglow candidate (GCN 9868)‏ • Estimated uncertainty of 4.2 arcseconds radius (90% confidence).Position is 3.2 arcmin from the reported LAT position, inside the LAT error radius. • 04:57:44 UT – Swift/UVOT observations, no afterglow confirmation (GCN 9869)‏ • 04:57:44 UT – enhanced Swift/XRT position (GCN 9871)‏ • 07:36:42 UT – Fermi LAT and GBM refined analysis (GCN 9872)‏ • 08:23:17 UT – Gemini-N absorption redshift (GCN 8973) z=1.822 (GMOS spectrograph)‏

  22. GRB 090902B - Autonomous Repoint Request • LAT pointing in celestial coordinates from -120 s to 2000 s • Red cross = GRB 090902B • Dark region = occulted by Earth (z>113°)‏ • White line = LAT FoV (±66°)‏ • Blue lines = 20° (Earth avoidance angle) / 50° above horizon • White points = LAT transient events (no cut on zenith angle) Public data  GRB090902B paper to be submitted to ApjL an arXiv this weekend

  23. Fermi LAT Science Working Groups • Analysis coordination • Nicola Omodei, S.Digel (deputy) • Science Working Groups • Calibration and Analysis Methods (L.Latronico/R.Rando, A. Borgland) • Beam Test (Latronico, Bruel) • IRF development (Rando), IRF monitoring (Cecchi) • Blazars and other AGNs (G.Tosti, E. Cavazzuti, B.Lott) • Diffuse and Molecular Clouds (T.Porter, A. Strong) • Catalogs (D.Thompson, J.Ballet) • Pulsars, SNR and Plerions (D.Smith, E.J.Grove) • GRB (F.Piron, V.Connaughton) • Sources in the Solar System (F.Longo, I. Moskalenko) • Dark Matter and new physics (S.Murgia, S.Ritz) • Satellite groups • Multiwavelength • GeV-TeV connection

  24. Fermi Year 1 Science Highlights • The Fermi Gamma-Ray Space Telescope successfully completed its first year of operation • Instrument performing very well and stable • Lots of exciting results ranging from astrophysics to fundamental physics • Data (and science analysis tools) are now public • Wealth of results in g-ray astrophysics • comprehensive g-ray sky catalogs • >60 pulsars detected, many only in g-rays; • many flaring active galaxies observed • 11 GRB • evidence of delayed and extended emission above 100MeV • some deviations from single Band function • Constraints on quantum gravity mass • no confirmation of the EGRET GeV-excess in diffuse emission • First high statistics measurement of CR electron spectrum (20 GeV – 1 TeV) • Harder wrt pre-Fermi conventional diffusive models • Improved conventional model • local sources, Pulsars or Dark Matter

  25. BACKUP

  26. A selection of g-ray pulsar light curves Blind search pulsars Abdo et al 2009 Science 325 840 Millisecond pulsars Abdo et al 2009 Science 325 848

  27. Globular Clusters: detection of 47 Tucanae Abdo, et al 2009 Science 325 845 energy spectrum well fitted by power law with exponential cutoff G = 1.3 ± 0.3; Ec = 2.5 GeV +1.6 - 0.8 LAT g-ray image (200 MeV – 10 GeV) of region centered on 47 Tuc. black contours: stellar density white circle: 95% confidence region for location of g-ray source Spectral shape and lack of observed time variability consistent with g-ray emission from population of millisecond pulsars

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