1. Fermi Large Area Telescope Year One Highlights
Ronaldo Bellazzini (INFN-Pisa)
Rappresentante nazionale INFN
collaborazione Fermi
Riunione Commissione Scientifica Nazionale II INFN
Roma, 1 ottobre 2009

3. Year 1 Science Operations Timeline Overview
August 12, 2009
Start Year 1
Science Ops
Start Year 2
Science Ops
LAT, GBM
turn-on check out
“first light”
whole sky
Observatory
renaming
spacecraft
turn-on checkout
sky survey + ~weekly GRB repoints + extraordinary TOOs
pointed + sky survey tuning
week week week week month m o n t h s
LAUNCH L+60 days
2nd
Symposium
June 11, 2008
initial tuning/calibrations
in-depth instrument studies
1st LAT Catalog
Release Flaring and Monitored Source Info
GBM and LAT GRB Alerts
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

4. 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

5. 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

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

7. 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

8. ~ 64 papers in Year 1
INFN CA in 26% of them

9. 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 C” (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

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

11. Fermi-LAT Cosmic-Ray Electron Spectrum
The APS published a total of about 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

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

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

14. NASA’s Fermi telescope reveals best-ever view of the gamma-ray sky
5 top sources within our Galaxy
the quiet sun (moving in the map)
LSI a high-mass X-ray binary
PSR J – a gamma-ray-only pulsar
47 Tucanae – a globular cluster of stars
unidentified, new and variable, 0FGL J
5 top sources beyond our Galaxy
NGC 1275 – the Perseus A galaxy
3C – a wildly flaring blazar
PKS – a flaring 10.1 billion ly away blazar
PKS – a quasar
unidentified known, 0FGL J

15. 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: v1 [astro-ph.HE] 8 Feb 2009

17. 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, – Fermi detection of 16 g-ray only pulsar
Science, 325, 845, – A population of ms g-ray pulsars seen with Fermi
Science, 325, 845, – Fermi detection of high energy g-ray emission in 47 Tuc
Several ApJ papers on specific meaningful pulsars (Vela, J20210, J1028 ….) + PSR catalog

18. Spectral measurements and emission models
Vela
Abdo, A. A. et al. 2009, ApJ, 696, 1084
PSR J
ApJ, 700, 1059
arXiv:
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

19. 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 (2.4×10-4 erg/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)
located at 12B light years from us using observations of optical afterglow by the GROND observatory

20. GRB 080916C - Highlights For the first time, can study time structure
8 keV – 260 keV
260 keV – 5 MeV
LAT raw
LAT > 100 MeV
LAT > 1 GeV T0
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 = /0.15
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)
Science 323, 1688 (2009)

21. 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 , submitted to Nature

22. Fermi GRBs through June 2009
10 LAT-detected high-energy bursts
+ 1 last friday
GRB C
GRB C – bright, long, z=4.35
GRB B – short
GRB A – LAT rate increase
GRB
GRB – ARR, z=3.6
GRB – ARR, z=0.736
GRB – short, intense, z=0.903
GRB
GRB B – bright, long, highest photon energy ever at 33 GeV
GRB – long, high energy, z=2.106

23. 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: 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)‏

24. GRB 090902B - Autonomous Repoint Request
LAT pointing in celestial coordinates from -120 s to 2000 s
Red cross = GRB B
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

25. 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

26. 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

27. BACKUP

28. A selection of g-ray pulsar light curves
Blind search pulsars
Abdo et al 2009 Science
Millisecond pulsars
Abdo et al 2009 Science

29. Globular Clusters: detection of 47 Tucanae
Abdo, et al 2009 Science
energy spectrum well fitted by power law with exponential cutoff
G = 1.3 ± 0.3; Ec = 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