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  • high |b|, non pulsar LAT bright source are associated to radio sources - 98/106 (92%) in LBAS have 8.4 GH flux density > 100 mJy - Log of radio luminosity is 39.0 < Log Lr < 45.3 [erg s^-1]

  • radio luminosity distribution is different for BL Lacs and FSRQ:
    • Log Lr, BLL = 42.8 +/- 1.1 [erg s^-1]

    • Log Lr, FSRQ = 44.4 +/- 0.6 [erg s^-1]

    • RG: NGC 1275 similar to BL Lacs (Log Lr = 42.2 [erg s^-1]), Cen A much less luminous (Log Lr = 39.1 [erg s^-1])

  • 8.4 GHz data are representative of radio flux density in general - negligible extended emission - flat spectrum compact cores, overluminous with respect to radio galaxies (except Cen A)
  • We have already a significant improvement over EGRET numbers, so we want to address the existence of actual correlation between radio and gamma ray properites. There's a number of bias/effects that we have to keep in mind, so we tried to look into different pairs of quantities
    • when we have z, we calculate luminosity and K-correct - else we just use S_84. and S_E>100 MeV
    • BL Lacs and FSRQ tend to populate different regions, so we make correlation analysis for full population and single classes separately
    • Spearman rank is used - partial analysis is used as far as luminosity are concerned

Data

Class

n. sources

Correlation coeff.

Chance probability

S_8.4-F_>100 MeV, mean

All

106

0.44

0.000001

S_8.4-F_>100 MeV, peak

All

106

0.38

0.000027

Log L_r-Log L_gamma

All

88

0.48

0.000001

S_8.4-F_>100 MeV, mean

FSRQ

57

0.22

0.050

S_8.4-F_>100 MeV, peak

FSRQ

57

0.21

0.064

Log L_r-Log L_\gamma

FSRQ

57

0.38

0.0021

S_8.4-F_>100 MeV, mean

BL Lacs

42

0.51

0.00036

S_8.4-F_>100 MeV, peak

BL Lacs

42

0.41

0.0039

Log L_r-Log L_gamma

BL Lacs

30

0.53

0.0013

  • peak gamma-ray flux and mean radio flux: hints of a weak correlation, but significativity is not so strong - even more when BL Lacs and FSRQ are considered separately
  • gamma-ray index and radio luminosity: the large energy band of LAT shows a clear difference in gamma-ray index for BL Lacs and FSRQ and this is apparent also in this diagram. Some outliers are also easy to spot: a radio galaxy (Cen A), a low energy peaked/low luminosity FSRQ, PMN J0948+0022

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