Документ взят из кэша поисковой машины. Адрес оригинального документа : http://hea.iki.rssi.ru/conf/hea2010/Presentations/22/Shtern.pdf Дата изменения: Wed Jan 26 13:25:08 2011 Дата индексирования: Tue Oct 2 00:44:52 2012 Кодировка: Поисковые слова: arp 220

Stern & Poutanen 2011

A very preliminary statistical study of blazar spectra
Spectral breaks in GeV range: Abdo et al. 2010 (Fermi collaboration): breaks are in the range 1 GeV and 10 GeV Poutanen & Stern 2010: significant breaks are in the range 2 ­ 4 GeV We extend the sample to see: - Are spectral breaks in GeV range a typical feature and how typical? - Can be all/most of breaks be explained by photon-photon absorption? (Are they in the correct place?) - Do we sense z-dependence?






Fermi catalog Blazars & AGNs 274 FSRQs 295 BL Lacs


3C454.3

Mrk501


Counts > 300 Mev/ 2 days

p3 3c454a p

n k l o

Days from the start of records Start 239557419 seconds from what? End 313035889 seconds (850-th day from the start)


Spectra: 1. Photon filtering: only class 3 (now 4), zenith angle < 105o 1. Exposure from spacecraft data (angular dependence) 2. Photon counts in a circle of energy dependent radius 0.5o ­ 10 according to the point spread function 3. Background measurement in a separated window 4. Normalisation to exposure and effective area
o


Log(erg/cm2/s)

3C 454a

Log (E,MeV)


2 = 11.8/9 2 = 7.8/9 2 = 2.6/9 2 = 5.6/9


He, H 2 = 18.2 BPL 2 = 16.7

3C 454A

3C 454a: significant correlation: hardness - brightness Marginally significant anticorrelation: optical depthbrightness


FSRQs with breaks

BL Lacs, HSP


FSRQs without breaks


BL Lacs with breaks (Low energy synchrotron peak)


3C 66a

2: 35

11


31 objects
Log(2) 11 DOF

2 = 20 (95%)

83 FSRQs 17 BLLs

Log (flux3GeV, erg/s/cm2)

Power law fit


Double absorber 2

Pks 0447 1ES 1011

3C 279(2) pks2023
Pks 2155 3C 66A

Pks0235, z=0.94, LSP Pks0537, z=0.89 LSP

Pks0426, z= 1.02, LSP

Power law 2


1. "good significant breaks" (21) z 3C454.3 PKS0537 Pks1502 PKS 0426 4C21 Pks 0454 AO 0235 S5 0716 Pks1424 4C 55 Pks 1124 3C66A PKS0244 Txs 1520 Oc457 Pks1510 Pks0716 4C38 Pks 1329 B1310 4C14 0.86 0.89 1.84 1.03 0.43 1. 0.94 0.31 1.52 0.89 1.05 0.44 1. 1.48 0.859 0.36 0.779 1.8 2.15 ? 1.04 2 PL 2HeH (11 dof) (9 dof) >200 3 - 18 105 21.1 81 9.7 67 13.8 67 9. 54 13.6 54 11. 53 8.3 49 18. 49. 7.3 48 17.5 33 11. 33. 9.1 33. 12.4 30. 6.0 28 10.8 28 13.7 25 11.6 24. 4.5 22 7.2 21 12

2. no significant breaks (40) z 3c279 3c273 Txs 1520 RGB 0920 PMN 2345 BL Lac Mrk 421 1ES1959 Mrk 501 Pks1244 Pks1454 Pks0208 Pks0402 Pks0301 0.54 0.16 1.49 2.19 0.62 0.07 0.03 0.05 0.63 1.4 1.0 1.4 0.26 2 PL 2 HeH 11 10 12.8 11 15.5 14.4 9. 15. 10 7.2 18. 15

10.4

5.4 4.4

+other nearby BL Lacs


Bad 2
PKS0537

Pks 0537

PKS1424 Background?

Breaks are still in the correct place!


Fit, z+1

Real z+1


Summary 1. A large fraction of spectra of bright blazars have a break at a few GeV 2. This half includes FSRQs and low synchrotron peak BL Lacs (probably misidentified) and does not include nearby (weak) classic BL Lacs 3. Some bright FSRQ does not show a break 4. Almost all breaks can be described by absorption by He II and H. Sometimes works only H. 5. Z-dependence is still not significant.