Diapositive 1

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New insight into Gamma-ray Blazars from the
Fermi-LAT Benoît Lott CEN Bordeaux-Gradignan o
n behalf of the Fermi-LAT collaboration
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Fermi-LAT as an all-sky monitor
OR103 FSRQ z1.83 ATEL 1650 S.Ciprini et al.
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3-month sky survey
TS100, photon index2.2
Flux(Egt100 MeV) ph cm-2s-1
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Two flavors of blazars FSRQs and BLLacs

• Defining property
• strong emission lines
• intense radiation field
• (disk, clouds)
• outside the jet
• High power (1046-48 erg/s)
• Parent population FRII
• Low synchrotron npeak (IR) in SED
• 46 FSRQs in EGRET all-sky survey (18 months)
• high redshift 0.1 lt z lt 2.3

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Two flavors of blazars FSRQs and BLLacs

• from the BL Lacerta archetype
• Defining property nearly lineless
• Low ambient radiation field
• Low power (1045-46 erg/s)
• Parent population FR I
• Low npeak (Opt/IR) LBL
• High npeak (UV/X-rays) HBL (TeV)
• 14 BLLacs in EGRET all-sky survey
• Low redshift 0lt z lt 0.9

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associations
0FGL 132 sources with TSgt100, bgt10
7 pulsars, 125 AGN candidates
BZCat (Massaro et al. 08) Compilation
of 2500 known blazars association based on
spatial coincidence (Mattox et al.,
01) 102 high-conf. (Pgt90) associations
4 low-conf. (40ltPlt90) associations
CGRaBS (Healey et al. 08) 1627 radio
sources from CRATES association based on
Figure-of-Merit (spatial, radio and X spectrum)
established from EGRET 101 high-conf.
(Pgt90) associations 14 low-conf. (40ltPlt90)
associations
celestial
galactic
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LAT Bright AGN Sample (LBAS)
57 FSRQ 42 BLLac 6 of Uncertain class 2 Radio
Galaxies
Preliminary

• 125 non-pulsar sources at bgt10
• 106 high-confidence (Pgt90) associations with
  AGNs (LBAS)
• 10 lower-confidence associations
• FSRQs 57
• BLLacs 42
• Uncertain class 5
• Radiogalaxies Cen A, NGC1275
• 40 BLLacs (23 for EGRET)
• 7 HBLs (31 for EGRET)
• 9 unidentified (3EG 96/181 at bgt10)

Q95 0.14 (EGRET sample 0.62)
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Flux vs index
Preliminary
FSRQ BLLac Uncertain Radio Galaxies
TS100 b20, 80 deg.
TS100 b 20 deg. Elt 3 GeV
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Flux distributions
Preliminary
weekly peak flux
mean flux
Fermi EGRET EGRET mean flux  1234 VP EGRET
peak flux maximum in 2-w VPs Fermi mean
flux 3-m averaged Fermi peak flux maximum in
1-w periods
peak/mean flux ratio
mean vs peak flux
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SED at LAT energies
Preliminary
3C454.3 (FSRQ) AO 0235165 (Int. BL)
Mkn501 (HBL)
Significant departures from pure power-law
distributions for bright blazars!
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Photon index distributions
Preliminary
all
FSRQs
Number of sources
ltGgt 2.330.01
BL Lacs
ltGgt1.990.01
Photon index
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LBAS Sources in 3EG
EGRET vs FERMI photon index
Preliminary
33 AGNs/116 LAT-sources (30) in 3EG catalog
with a comparable flux ? duty cycle Others
are found at lower fluxes FSRQs 20 BLLacs
11 Uncertain 3 Radio galaxy1
FSRQ BLLac Uncertain Radio galaxies
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Redshift distributions
Preliminary
Preliminary
Mukherjee et al. 1999
EGRET
FSRQ BLLac Uncertain Radio galaxies
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Log N - Log S
Preliminary
Preliminary
FSRQs

•  sky coverage  enables the log N-LogS to be
  computed
• Euclidian space slope2.5

BL Lacs
Marco Ajello
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Luminosity vs redshift
Preliminary
FSRQ BLLac Uncertain Radio galaxies
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ltV/Vmaxgt test
ltV/Vmaxgt ratio between the comoving volume
within which the source was detected and the
maximum volume available for its
detection Population uniformly distributed in
Euclidian space, non evolving ltV/Vmaxgt 0.5
Preliminary
Positive evolution for FSRQs (more FSRQs in the
past) Compatible with no evolution for BLLacs
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Perspectives

• Luminosity function
• Contribution of unresolved blazars to
  Extragalactic Diffuse Background
• Variability on different timescales
• Duty cycle of blazars
• Existence of a blazar sequence ?
• (evolutionary link between FSRQs and BLLacs?)
• Gamma-ray radio connection