Gamma rays from microquasars Cygnus X-1 and Cygnus X-3 ICRC 2017 - - PowerPoint PPT Presentation

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Gamma rays from microquasars Cygnus X-1 and Cygnus X-3 ICRC 2017 - - PowerPoint PPT Presentation

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Gamma rays from microquasars Cygnus X-1 and Cygnus X-3 ICRC 2017 Busan, 12-20 July 2017 A. Fernndez-Barral ( afernandez@ifae.es ) O. Blanch, E. de Oa Wilhelmi, D. Galindo, J. Herrera, M. Rib, J. Rico, A. Stamerra (for the MAGIC

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SLIDE 1

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

ICRC 2017 Busan, 12-20 July 2017

  • A. Fernández-Barral (afernandez@ifae.es)
  • O. Blanch, E. de Oña Wilhelmi, D. Galindo, J. Herrera, M.

Ribó, J. Rico, A. Stamerra (for the MAGIC Collaboration), F . Aharonian, V. Bosch-Ramon, R. Zanin

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SLIDE 2
  • A. Fernández-Barral, ICRC 2017, Busan July 12-20

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

Microquasars

2

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SLIDE 3
  • A. Fernández-Barral, ICRC 2017, Busan July 12-20

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

SOFT STATE (SS)

Microquasars: X-ray states

3

INTERMEDIATE

HARD STATE (HS)

Comptonization on thermal photons in the corona

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SLIDE 4
  • A. Fernández-Barral, ICRC 2017, Busan July 12-20

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

HARD STATE (HS)

Microquasars: X-ray states

4

SOFT STATE (SS)

INTERMEDIATE

Blackbody emission from the disk

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SLIDE 5
  • A. Fernández-Barral, ICRC 2017, Busan July 12-20

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

Basic information

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25-35 M⊙ O9.7 Iab supergiant + 15 M⊙ BH Distance ~ 1.86 kpc, Rorb~3x1012 cm Orbital period = 5.6 days X-ray and radio orbital modulation SUPC @ phase=0 5 pc ring-like radio structure (@ 1019 cm) Wolf Rayet + 1.4 M⊙ NS or <10 M⊙ BH Distance ~ 7 kpc, Rorb~2.5x1011 cm Orbital period = 4.8 hr X-ray and HE gamma-ray orbital modulation SUPC @ phase=0 Unusual high absorption Detected @ HE by AGILE and Fermi-LAT

Cygnus X-1 Cygnus X-3

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SLIDE 6
  • A. Fernández-Barral, ICRC 2017, Busan July 12-20

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

Cygnus X-1: HE and VHE emission

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◆Three transient episodes (~1-2 d) detected by AGILE (>100 MeV): two first @ HS , one during IS (Bulgarelli+2008;Sabatini+2010, 2013) ◆Hint @ TS=16 with 3.8 yr Fermi-LAT data during HS (Malyshev+2013) ◆Evidence of emission @ VHE with MAGIC (mono): Sept 2006, ~4σ in 80 min, dΦ/dE =(2.3±0.6)x10-12 (Ε/1 ΤeV)-3.2±0.6 TeV-1cm-2s-1 (Albert+2007)

  • Simultaneously with hard X-ray flare (seen by INTEGRAL, Swift-BAT and

RXTE-ASM)

  • During HS and SUPC
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SLIDE 7
  • A. Fernández-Barral, ICRC 2017, Busan July 12-20

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

Cygnus X-1: new results at HE

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◆7.5 yr PASS8 Fermi-LAT data from 60 MeV to 500 GeV => Firmly detection with TS=53 ◆Detection only happens during HS ◆Power-law with Γ=2.3±0.1, N0=(5.8±0.9)x10-13 MeV-1cm-2s-1, from 60 MeV up to ~20 GeV

Zanin, Fernández-Barral, et al., A&A, 596, A55 (2016)

HS SS

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SLIDE 8
  • A. Fernández-Barral, ICRC 2017, Busan July 12-20

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

Cygnus X-1: new results at HE

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◆Hint of orbital variability: detection only during SUPC (TS=31) using HS data SUPC 0.75<phase<0.25 INFC 0.25<phase<0.75

Zanin, Fernández-Barral, et al., A&A, 596, A55 (2016)

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SLIDE 9
  • A. Fernández-Barral, ICRC 2017, Busan July 12-20

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

Cygnus X-1: new results at VHE

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◆MAGIC observations between 2007-2014, for ~ 100 hr (mainly @ HS) ◆We searched for steady and variable emission >200 GeV, at each X-ray state (~83 hr HS, ~14 hr SS) ◆No significant excess was found for steady, orbital modulated or daily basis emission ◆Upper limits (ULs) at 95% CL and 30% systematics using full likelihood method from Aleksic+2012a ◆Assuming power law with Γ=3.2

MJD

54500 55000 55500 56000 56500 57000

mJy

5 − 5 10 15 20 25 30

RATAN 4.6 GHz AMI 15GHz

)

  • 2

(cm

  • 1

cts s

1 2 3 4 5 MAXI 2-20keV 10) 3-5keV ÷ RXTE-ASM( 10) 15-50keV × Swift-BAT(

]

  • 6

10 × [

  • 1

s

  • 2

ph cm

0.5 1 1.5 2

Fermi-LAT 0.1-20GeV

]

  • 11

10 × [

  • 1

s

  • 2

ph cm

5 10 15

MAGIC >200 GeV

MAGIC Collaboration et al., submitted to MNRAS (2017)

Preliminary

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SLIDE 10
  • A. Fernández-Barral, ICRC 2017, Busan July 12-20

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

Cygnus X-1: implications of HE new results

◆To avoid absorption: emission outside the corona (> 109 cm) ◆Only during HS: most likely @ jets ◆Hint of orbital modulation: jet-medium interaction discarded (< 1013 cm)

  • Expected anisotropic inverse

Compton on stellar photons: > 1011 cm IC on thermal photons IC on stellar photons IC on surrounding (photon-photon absorption)

Discarded

(photon-photon absorption)

Discarded

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SLIDE 11
  • A. Fernández-Barral, ICRC 2017, Busan July 12-20

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

Energy [eV]

3

10

4

10

5

10

6

10

7

10

8

10

9

10

10

10

11

10

12

10

13

10

14

10

15

10 ]

  • 1

s

  • 2

dN/dE [erg cm

2

E

14 −

10

13 −

10

12 −

10

11 −

10

10 −

10

9 −

10

8 −

10

7 −

10

BeppoSax HS (Di Salvo et al.,2001) INTEGRAL-ISGRI HS (Rodriguez et al.,2015) INTEGRAL-PICsIT HS (Zdziarski et al.,2012) Fermi-LAT HS (Zanin et al.,2016) MAGIC HS (This work) CTA 50h-sensitivity CTA 200h-sensitivity

Cygnus X-1: implications of VHE new results

◆Jet-medium interaction discarded: not affected by γ-γ absorption ◆@ binary scale less conclusive:

  • Transient event, as reported previously,

cannot be ruled out (no observations simultaneously with hard X-ray flare)

  • Radio-emitting-blobs during IS (like in

Cygnus X-3)

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Preliminary

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SLIDE 12
  • A. Fernández-Barral, ICRC 2017, Busan July 12-20

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

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◆Radio and HE gamma-ray flare in Aug-Sept 2016 ◆MAGIC observations between Aug 23rd and Sept 22nd: ~70 hr during SS ◆Searches for steady, orbital modulated and daily basis analysis: no significant excess

  • ULs at 95% CL assuming

power law with Γ=2.6

Cygnus X-3: new results at VHE

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SLIDE 13
  • A. Fernández-Barral, ICRC 2017, Busan July 12-20

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

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◆Non-negligible absorption, τ~σγγ·nNIR·R, up to R~1013 cm

  • assuming σγγ~10-25 cm, LNIR=1038 erg/s

◆VHE emission could be related with HE production site (@ binary scales, R>1011 cm) ◆Already very constraining ULs: further investigation with Fermi-LAT data

Cygnus X-3: new results at VHE

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SLIDE 14
  • A. Fernández-Barral, ICRC 2017, Busan July 12-20

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

◆Cygnus X-1 firmly detected in the HE regime. No significant excess found @ VHE ◆HE emission up to ~20 GeV, most likely related to relativistic jets ◆Probable mechanism anisotropic IC on stellar photons ◆HE emission site constrained at 1011 cm < R < 1013 cm from the BH ◆No HE cutoff detected => TeV component not excluded, but expected @ binary scales ◆VHE transient event, as previously reported by MAGIC, cannot be ruled out

Conclusions

Cygnus X-1 Cygnus X-3

◆MAGIC observed Cygnus X-3 covering a radio and HE flare ◆VHE gamma rays not detected (neither steady or variable emission) ◆TeV emission could be produced inside the system, where high absorption would avoid detection with current IACTs

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SLIDE 15

Thanks for your attention

ICRC 2017 Busan, 12-20 July 2017

  • A. Fernández-Barral (afernandez@ifae.es)
  • O. Blanch, E. de Oña Wilhelmi, D. Galindo, J. Herrera, M.

Ribó, J. Rico, A. Stamerra (for the MAGIC Collaboration), F . Aharonian, V. Bosch-Ramon, R. Zanin