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The variable CRAB Nebula E . Striani, INAF-IAPS, University of Rome Tor Vergata (on behalf of the AGILE team) Fermi Symposium, Monterey 30 Nov. 2012

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Page 1: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

The variable CRAB Nebula E . Striani, INAF-IAPS, University of Rome Tor Vergata (on behalf of the AGILE team)

Fermi Symposium, Monterey 30 Nov. 2012

Page 2: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

Crab Nebula spectrum

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Unpulsed (nebular) gamma-ray spectrum (Abdo et al 2010)

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The Crab Nebula

1.  Stable (Standard candle)

2.  Cut-off in the spectrum around 150 MeV

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AGILE,    26  Nov.  –  13  Oct.  2007   Fermi-­‐LAT,  26  Jan.  –  11  Feb.  2009  

2000  

1000  

   500  

Fermi-­‐AGILE,  12  –  20  Apr.  2011  AGILE,    20-­‐22  Sept.  2010  

major flare rate: 1-2/year

Page 6: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

Agile Spectrum at the peak (12 hr) (Striani et al. 2011)

Superflare Apr. 2011

Page 7: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

Overview of the main gamma-ray flares

Page 8: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ
Page 9: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ
Page 10: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ
Page 11: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

Striani et al., submitted to ApJ

Page 12: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

The 2007 AGILE event

Page 13: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

AGILE 1-day bin lightcurve of the 2007 event

Striani et al., submitted to ApJ

Page 14: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

AGILE 12-hr bin lightcurve of the 2007 event

Striani et al., submitted to ApJ

Page 15: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

Striani et al., submitted to ApJ

Page 16: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

Fermi Data

Page 17: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

Fermi Atel # 4239 (July 2012, during the Flaring Crab meeting in Frascati) (data from the Fermi-LAT monitored source list page)

1-day bin

Page 18: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

Gamma-ray 2-day binned lightcurve (Fermi data)

Page 19: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

The Crab •  A standard candle

•  Strong and impulsive flares (12-24 hr), ∼1/year

•  Slower, less intense variability, and rather more frequent (waves)

Page 20: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

•     

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Modelling of the April 2011 super-flare

AGILE Fermi

Maxwellian γmin = 7·108, B = 1mG

power-law dN(γ)/dγ = γ-p1, p1 = 2.1, γb = 6·108

Page 22: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

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• No smoking gun

• No apparent relation between X-ray and gamma emission

• Mono-energetic (relativ. Maxwellian) distribution is favored

(M. Weisskopf, 2012)

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already several models, many ideas… •  Tavani et al. (2011, 2012) •  Abdo et al. (2011, 2012) •  Bednarek & Idec (2011) •  Komissarov & Lyutikov (2011) •  Vittorini et al., Striani et al. (2011) •  Lyutikov, Balsara, Matthews (2011) •  Bykov, Pavlov, Artemyev, Uvanov (2011) •  Cerutti, Uzdensky, Begelman (2012) •  Arons (2012) •  Lyubarsky (2012) •  Sturrock & Aschwanden (2012) •  Kommissarov (2012) •  Blandford & Li (2012) •  Mignone et al. (2012, in prep.) •  Striani el al. (2012, in prep.)

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Page 24: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

•     

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Conclusions •  Four major flares from the Crab Nebula, that

challenged previous theoretical models of particle acceleration in PWN

•  evidence for 2 types of enhanced emission, fast (flares) and slow (“waves”)

•  Gamma-ray continuous monitoring of the Crab is really crucial: flares discovered because of this capability by AGILE and Fermi

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Thank You

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backup

Page 33: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

•     

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Flare 2011 (Fermi data)

Agile  Spectrum  at  the  peak  (12  hr)  (Striani  et  al.  2011)  

Page 35: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

Super Flare 2011 Fermi data

Page 36: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

CRAB Nebula Superflare (R. Buehler et al. 2011)

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The Crab major gamma-ray flare in April 2011

Page 38: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

The Crab major gamma-ray flare in April 2011

1  

(R.  Buehler  et  al.  2011,  elaborated  by  E.  S.)  

Page 39: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

The Crab major gamma-ray flare in April 2011

2  

(R.  Buehler  et  al.  2011,  elaborated  by  E.  S.)  

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The Crab major gamma-ray flare in April 2011 (R.  Buehler  et  al.  2011,  elaborated  by  E.  S.)  

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The Crab major gamma-ray flare in April 2011 (R.  Buehler  et  al.  2011,  elaborated  by  E.  S.)  

Page 42: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

The Crab major gamma-ray flare in April 2011

5

(R.  Buehler  et  al.  2011,  elaborated  by  E.  S.)  

Page 43: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

The Crab major gamma-ray flare in April 2011

5

(R.  Buehler  et  al.  2011,  elaborated  by  E.  S.)  

Page 44: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

The Crab major gamma-ray flare in April 2011

6  

(R.  Buehler  et  al.  2011,  elaborated  by  E.  S.)  

Page 45: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

The Crab major gamma-ray flare in April 2011

7  7  

(R.  Buehler  et  al.  2011,  elaborated  by  E.  S.)  

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The Crab major gamma-ray flare in April 2011 (R.  Buehler  et  al.  2011,  elaborated  by  E.  S.)  

Page 47: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

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The Crab major gamma-ray flare in April 2011 (R.  Buehler  et  al.  2011,  elaborated  by  E.  S.)  

Page 48: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

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The Crab major gamma-ray flare in April 2011 (R.  Buehler  et  al.  2011,  elaborated  by  E.  S.)  

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The Crab major gamma-ray flare in April 2011 (R.  Buehler  et  al.  2011,  elaborated  by  E.  S.)  

Page 50: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

Striani  et  al.,  submiBed  to  ApJ  

Page 51: The variable CRAB Nebula · Agile Spectrum at the peak (12 hr) (Striani et al. 2011) Superflare Apr. 2011 . Overview of the main gamma-ray flares . Striani et al., submitted to ApJ

Striani  et  al.,  submiBed  to  ApJ  

AGILE observations of the Crab Nebula in pointing mode (Sept. 2007 - Oct. 2009)

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The CRAB •