F.Fuschino, F.Longo et al. -- 1 AGILE view on TGF F. Fuschino, F. Longo, M. Marisaldi, C. Labanti,...

F.Fuschino, F.Longo et al. -- 1

AGILE view on TGF AGILE view on TGF

F. Fuschino, F. Longo, M. Marisaldi, C. Labanti, M. Galli, G. Barbiellini

on behalf of the AGILE team


OutlineOutline

• The AGILE satellite– Brief introduction

• The AGILE Mini Calorimeter (MCAL)– Burst Trigger Mode– Gamma-ray Burst detection

• Terrestrial Gamma Flashes – Detection by AGILE-MCAL

The AGILE first photon – May 10, 2007


AGILEAGILE

AGILE AGILE


Detection TechniqueDetection Technique


AGILE instrumentAGILE instrument


AGILE: inside the cube…

ANTICOINCIDENCE

INAF-IASF-Mi (F.Perotti)

HARD X-RAY IMAGER (SUPER-AGILE)

INAF-IASF-Rm (E.Costa, M. Feroci)

GAMMA-RAY IMAGER

SILICON TRACKER

INFN-Trieste

(G.Barbiellini, M. Prest)

(MINI) CALORIMETER

INAF-IASF-Bo, Thales-Alenia Space (LABEN)

(G. Di Cocco, C. Labanti)


Sriharikota launch base (India)

PSLV-C8 launch, April 23, 2007

The AGILE instrumentThe AGILE instrument


• Vela, Geminga, Crab PSR timing• Monitoring of many Galactic hard X-ray sources• Blazar detections

– 3C 279– 3C 273– 3C 454.3 (repeated gamma-ray flares)– PKS1510-089– 0716+714 – W Comae, Mkn 421

• Several GRBs detected by SuperAGILE and MCAL (MCAL detects ~ 1/week)

• Discovery of transient gamma-ray sources in the Galactic plane.

AGILE resultsAGILE results


3C 454.3

Cygnus region

AGILE gamma-ray sky: 22 Nov. 2007


AGILE view of the skyAGILE view of the sky

http://agile.iasf-roma.inaf.it

http://agile.asdc.asi.it


The AGILE MCALThe AGILE MCAL


The Mini-Calorimeter (MCAL)The Mini-Calorimeter (MCAL)

30 CsI(Tl) bars with Photodiode readout 1400 cm2 geometrical area ~360 cm2 effective area @ 1 MeV 330 keV – 100 MeV energy range 14% energy resolution FWHM @ 1.3 MeV 2 ms timing accuracy in photon-by-photon mode Clever, fully-programmable GRB trigger logic

40 cm


On Board AGILE TriggerOn Board AGILE Trigger

BURST-GRB SEARCH-SA IMAGEDECONVOLUTION

TELEMETRY



MCAL Trigger LogicMCAL Trigger Logic

MCAL Burst Search logic: 1ms, 16ms, 64ms, 256ms, 1.024s, 8.192s Search Integration Time (SIT) 4 spatial zones and 3 energy ranges (<700 keV, 700-1400 keV, >1400 keV) static and dinamic thresholds for start and stop generation dedicated look-up tables to accept/reject triggers very flexible: more than 2000 parameters for full configuration

Configured in November 2007, steadily active since February 2008


MCAL GRB search testing MCAL GRB search testing (Tortona, June 2006)(Tortona, June 2006)



MCAL and its partners in spaceMCAL and its partners in space

49 cosmic GRBs detected by AGILE-MCAL between 22nd June '07 - 11th June. '08. Most of them confirmed by other InterPlanetary Network (IPN) spacecrafts

Detectors with spectral capabilities in the MeV range

Detector with photon-by-photon microsecond timing accuracy in the MeV range

Detector with superposition > 80% with the MCAL sample and good spectral capabilities: cross-calibration activity ongoing

A warm welcome to GLAST-GBM!


Latest news: GRB 080609Latest news: GRB 080609

25 s

long, bright GRB, multipeaked,out of FOV


Latest news: GRB 080611Latest news: GRB 080611

100 ms

short/hard, very bright


Terrestrial Gamma Flashes by AGILETerrestrial Gamma Flashes by AGILE


Terrestrial Gamma-ray Flashes (TGF)Terrestrial Gamma-ray Flashes (TGF)

Gamma-ray flashes with incoming direction compatible with the Earth surface. Few millisecond typical duration; hard spectrum (detected up to 20 MeV) Discovered by BATSE (1994) and confirmed by RHESSI (2006) Possibly associated to lightning during thunderstorms by means of correlation with VLF spheric waves detection on ground

Serendipitous detection of candidate TGF by MCAL after the onset of the onboard trigger logic Undetectable without small “search integration times” (<=64 ms) and photon-by-photon data download About 20 candidates in 5 months operation


MCAL candidate TGFMCAL candidate TGF

10 ms

trigger date and time

temporal bin: 100 s! time scale: < 5 ms


TGF energy/position distributionTGF energy/position distribution

AGILE position at trigger time

AGILE pointing at trigger time

FOVCandidate TGF on 2007-12-11 00:03: 42 UT

Light curves in 2 energy bands

Events distribution in 2 energy bands

The position distribution pattern is compatible with incoming direction from the Earth surface

Earth


TGF energy/position distributionTGF energy/position distribution

AGILE position at trigger time

AGILE pointing at trigger time

EarthCandidate TGF on 25/3/08 15:00:02

Light curves in 3 energy bands

Events distribution in 3 energy bands

The position distribution pattern is compatible with incoming direction from the Earth surface


Geographycal distributionGeographycal distribution


EnergeticsEnergetics

Are the observed MCAL events compatible with RHESSI spectra?

Smith et al. 2005

Considering RHESSI and MCAL effective area ~12 counts/ms are expected in MCAL in the 500 – 700 keV band ~16 counts/ms are found: quite good agreement, refinement are expected with better calibration possibly selection effect toward bright events due to the trigger time window (64ms): expected improvements with <=16ms time windows


ConclusionsConclusions

• AGILE-MCAL is the 3rd instrument (after BATSE and RHESSI) that observed TGF from space. Serendipity: from astrophysics to geophysics!

• Observation of such fast events is only possible thanks to the clever trigger logic (~ms time scale) and photon-by-photon data download with ms time resolution.

• The energetics of observed events is compatible with that reported by RHESSI.

• Definitive proof needed: search for spheric waves correlation

• Calibration activity ongoing: better spectral characterization

• Last week: enabling <16 ms time window: new discovery space opening!

• HW trigger 1, 16 ms + 293 s (<1 ms)


The endThe end

thank you !


BackUp SlidesBackUp Slides


BATSE TGF

~ 70 TGF detected on 9 life-Years typically 100 counts/TGFOn-Board Trigger Logic performances:Shorter timescale => 64msSignificance => 40 sigma above the background on two separate detector

Fishman et al. 1994Ostgaard et al. 08


RHESSI TGFRHESSI TGF

TGF Distributionwith lighting frequencyper km2 per Year

Continuous time-tagged event list NO ON-BOARD TRIGGER LOGIC10– 20 TGF per monthTypically 20-30 counts/TGF

Distribution of average energy for theRHESSI TGFs (histogram) along with a simulated brehmstrahlung spectra. Smith et al. 2005

F.Fuschino, F.Longo et al. -- 1 AGILE view on TGF F. Fuschino, F. Longo, M. Marisaldi, C. Labanti,...

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