Igor V. MoskalenkoIgor V. MoskalenkoStanford UniversityStanford University

on behalf of the Fermi LAT on behalf of the Fermi LAT Collaboration Collaboration and the Fermi missionand the Fermi mission

RESULTS FROM THE RESULTS FROM THE FIRST MONTHS OF THE FIRST MONTHS OF THE FERMI GAMMA-RAY FERMI GAMMA-RAY SPACE TELESCOPE SPACE TELESCOPE MISSIONMISSION

• gamma rays provide a direct view into Nature’s largest gamma rays provide a direct view into Nature’s largest accelerators (neutron stars, black holes)accelerators (neutron stars, black holes)

• gamma rays probe cosmological distancesgamma rays probe cosmological distances (e.g., (e.g., + + EBLEBL e e++ + e + e--))

• huge leap in key capabilities, including a largely unexplored huge leap in key capabilities, including a largely unexplored energy range; great potential for discovery: e.g. dark energy range; great potential for discovery: e.g. dark mattermatter

TwoTwo instruments: Large Area Telescope (LAT), 20 MeV - >300 GeVinstruments: Large Area Telescope (LAT), 20 MeV - >300 GeV

Gamma-ray Burst Monitor (GBM), 10 keV - 25 MeVGamma-ray Burst Monitor (GBM), 10 keV - 25 MeV

LAT

GBM

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

Year 1 Science Operations Timeline Year 1 Science Operations Timeline OverviewOverview

LLAUNCH AUNCH LL+60 days+60 days

week week week week month 12 m o n t h s week week week week month 12 m o n t h s

spacecraftspacecraftturn-on checkoutturn-on checkout

LAT, LAT, GBMGBMturn-on turn-on check check outout

““first light”first light”whole skywhole sky

initial tuning/calibrations

pointed + sky pointed + sky survey tuningsurvey tuning

Start Year 1 Start Year 1 Science OpsScience Ops

Start Year 2 Start Year 2 Science OpsScience Ops

in-depth instrument studies

sky surveysky survey + ~weekly GRB + ~weekly GRB repoints + extraordinary TOOsrepoints + extraordinary TOOs

Release Flaring and Monitored Source Info

GBM and LAT GRB Alerts

continuousrelease of new

photon data

ObservatoryObservatoryrenamingrenaming

GI Cycle 1 GI Cycle 1 Funds ReleaseFunds Release

Fellows Year 1Fellows Year 1StartStart

LAT 6-monthLAT 6-monthhigh-confidencehigh-confidencesource release, GSSC source release, GSSC science tools advance science tools advance releaserelease

GI Cycle 2GI Cycle 2ProposalsProposals LAT Year 1 photonLAT Year 1 photon

data release PLUSdata release PLUSLAT Year 1 CatalogLAT Year 1 Catalogand Diffuse Modeland Diffuse Model

2nd2ndSymposiumSymposiumJune 11, 2008June 11, 2008

August 12, 2009August 12, 2009

> 2000 AGNs> 2000 AGNsblazars and radiogal = f(,z)

evolution z < 5Sag A*

10-5010-50 GRB/yearGRB/yearGeV afterglow

spectra to high energy

Cosmic rays and cloudsCosmic rays and cloudsacceleration in Supernova remnants

OB associationspropagation (Milky Way, M31, LMC, SMC)

Interstellar mass tracers in galaxies

PossibilitiesPossibilitiesstarburst galaxies

galaxy clustersmeasure EBL

unIDs

Dark MatterDark Matterneutralino lines

sub-halo clumps

-ray binaries-ray binariesPulsar winds-quasar jets

PulsarsPulsarsemission from radio and X-ray pulsars

blind searches for new Gemingasmagnetospheric physics

pulsar wind nebulae

20 MeV - > 300 GeV20 MeV - > 300 GeV

CR electronsCR electrons20 GeV – a few TeV

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

FranceFrance IN2P3, CEA/Saclay

ItalyItaly INFN, ASI, INAF

JapanJapan Hiroshima University ISAS/JAXA RIKEN Tokyo Institute of Technology

SwedenSweden Royal Institute of Technology (KTH) Stockholm University

United StatesUnited 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

…. Transient class

Source class

Diffuse class

multiple scattering dominates

Finite pitch of Si strips

  YearsYears Ang. Res.Ang. Res.(100 MeV)(100 MeV)

Ang. Res. Ang. Res. (10 GeV)(10 GeV)

Eng. Rng. Eng. Rng. (GeV)(GeV)

AAeffeff Ω Ω

(cm(cm22 sr) sr)# # -rays-rays

EGRETEGRET 1991–001991–00 5.8°5.8° 0.5°0.5° 0.03–100.03–10 750750 1.4 × 101.4 × 1066/yr/yr

AGILEAGILE 2007–2007– 4.7°4.7° 0.2°0.2° 0.03–500.03–50 1,5001,500 4 × 104 × 1066/yr/yr

Fermi LAT

2008– 3.5° 0.1° 0.02–300 25,000 1 × 108/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 Monitorwhole sky every ~3 hours

CGRO EGRET

June 11, 200812:05 pm (EDT)

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

14

205 sources

- based on first 3 months of sky-survey- based on first 3 months of sky-survey

arXiv:0902.1340v1 [astro-ph.HE] 8 Feb 2009

205 Preliminary LAT Bright Sources 205 Preliminary LAT Bright Sources

Census of Associations (not Identifications) Census of Associations (not Identifications)

ClassClass NumberNumber

Radio/X-ray pulsarRadio/X-ray pulsar 1515

LAT pulsarLAT pulsar 1414

Globular cluster (pulsars?)Globular cluster (pulsars?) 11

HMXBHMXB 22

LMC LMC 11

Flat Spectrum Radio QuasarsFlat Spectrum Radio Quasars 6262

Bl Lac ObjectsBl Lac Objects 4646

Blazar, uncertain typeBlazar, uncertain type 1111

Radio galaxiesRadio galaxies 22

Special cases (under study)Special cases (under study) 1414

UnassociatedUnassociated 3737

EGRET pulsarsEGRET pulsars

young pulsars discovered using radio ephemerisyoung pulsars discovered using radio ephemeris

pulsars discovered in blind searchpulsars discovered in blind search

33 gamma-ray and radio pulsars (including nine ms psrs)33 gamma-ray and radio pulsars (including nine ms psrs)

16 gamma-ray only pulsars16 gamma-ray only pulsars

High-confidence detections through 2/28/2009

millisecond pulsars discovered using radio ephemerismillisecond pulsars discovered using radio ephemeris

Pulses at 1/10th real rate

• LAT has reported 6 high-energy bursts since LAT has reported 6 high-energy bursts since launchlaunch

long-duration bursts

First detection of short-duration burst at high energy

Z = 4.35 ± 0.15Z = 4.35 ± 0.15

For the first time, For the first time, can study time can study time structure > tens of structure > tens of MeV.MeV.

Feature in the LC:Feature in the LC:— pulse in interval pulse in interval

“a” disappears “a” disappears at LAT energies.at LAT energies.

Science Express, 19 Feb 2009, pg 1

For this burst, For this burst, absorption arguments absorption arguments provide a stringent provide a stringent lower limit of lower limit of minmin = 860 = 860

August 3 – October 30, 2008August 3 – October 30, 2008

July 1 – Sept 24, 2008

August 3 – August 7, 2008

EGRET observations showed excess emission > 1 GeV when compared with conventional model tuned to reproduce local cosmic-ray nuclei and electron spectra

• Variety of explanationsVariations in cosmic-ray

spectra over Galaxy

Unresolved sources (pulsars, SNRs, …)

Dark matter

Instrumental~100% discrepancy > 1 GeV~100% discrepancy > 1 GeV

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

► 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)

E2 d

J/dE

(keV

/(cm

2-s

-keV

-sr)

EGRET

steep-spectrum quasars

Seyfert II galaxies

Seyfert I galaxies

Type 1a Supernovae

discovery spacediscovery space• blazars• normal galaxies• cluster mergers• primordial diffuse• new physics

EGRET

Fermi LAT is expected to detect ~107 electrons/yr above 20 GeV, 4×105 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 heliosphereStay tuned! CR electron spectrum will be released on May 2 (APS meeting)

Fermi Gamma-ray Space TelescopeFermi Gamma-ray Space Telescope fully fully operational.. operational..

In first few days of sky survey, the LAT In first few days of sky survey, the LAT corroborated many of the great discoveries of corroborated many of the great discoveries of EGRET; now finding new sources as well;EGRET; now finding new sources as well;

With 3 months of the 1With 3 months of the 1stst year all-sky survey year all-sky survey phase;phase; large number of pulsars detected, some only in large number of pulsars detected, some only in --

rays;rays; many flaring active galaxies observed; about half many flaring active galaxies observed; about half

not seen by EGRET;not seen by EGRET; Flaring sources observed along the galactic plane;Flaring sources observed along the galactic plane; High-energy emission seen from 3 GRBs; first time High-energy emission seen from 3 GRBs; first time

seen from short-duration burst;seen from short-duration burst; Quiescent sun detected at high energies;Quiescent sun detected at high energies; Major progress in understanding galactic diffuse Major progress in understanding galactic diffuse

emissionemission

With time, With time, FermiFermi will probe deeper and deeper will probe deeper and deeper into the high-energy Universe into the high-energy Universe