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

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

A. Fernández-Barral, ICRC 2017, Busan July 12-20 Gamma rays from microquasars Cygnus X-1 and Cygnus X-3 Microquasars 2

A. Fernández-Barral, ICRC 2017, Busan July 12-20 Gamma rays from microquasars Cygnus X-1 and Cygnus X-3 Microquasars: X-ray states SOFT STATE (SS) HARD STATE (HS) INTERMEDIATE Comptonization on thermal photons in the corona 3

A. Fernández-Barral, ICRC 2017, Busan July 12-20 Gamma rays from microquasars Cygnus X-1 and Cygnus X-3 Microquasars: X-ray states SOFT STATE (SS) HARD STATE (HS) INTERMEDIATE Blackbody emission from the disk 4

A. Fernández-Barral, ICRC 2017, Busan July 12-20 Gamma rays from microquasars Cygnus X-1 and Cygnus X-3 Basic information Cygnus X-1 Cygnus X-3 25-35 M ⊙ O9.7 Iab supergiant + 15 M ⊙ BH Wolf Rayet + 1.4 M ⊙ NS or <10 M ⊙ BH Distance ~ 1.86 kpc, R orb ~3x10 12 cm Distance ~ 7 kpc, R orb ~2.5x10 11 cm Orbital period = 5.6 days Orbital period = 4.8 hr X-ray and radio orbital modulation X-ray and HE gamma-ray orbital modulation SUPC @ phase=0 SUPC @ phase=0 5 pc ring-like radio structure (@ 10 19 cm) Unusual high absorption Detected @ HE by AGILE and Fermi -LAT 5

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 ◆ 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, ~4 σ in 80 min, d Φ /dE =(2.3±0.6)x10 -12 ( Ε /1 Τ eV) -3.2±0.6 TeV -1 cm -2 s -1 (Albert+2007) - Simultaneously with hard X-ray flare (seen by INTEGRAL, Swift -BAT and RXTE -ASM) - During HS and SUPC 6

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 Zanin, Fernández-Barral, et al., A&A, 596, A55 (2016) ◆ 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, N 0 =(5.8±0.9)x10 -13 MeV -1 cm -2 s -1 , from 60 MeV up to ~20 GeV HS SS 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 Zanin, Fernández-Barral, et al., A&A, 596, A55 (2016) ◆ Hint of orbital variability: detection only during SUPC (TS=31) using HS data SUPC INFC 0.75< phase <0.25 0.25< phase <0.75 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 VHE MAGIC Collaboration et al., submitted to MNRAS (2017) ◆ MAGIC observations between 15 MAGIC >200 GeV Preliminary 2007-2014, for ~ 100 hr (mainly @ ] -11 10 10 × HS) [ -1 s 5 -2 ph cm 0 ◆ We searched for steady and variable emission >200 GeV, at each X-ray 2 Fermi-LAT 0.1-20GeV ] state (~83 hr HS, ~14 hr SS) -6 10 1.5 × [ -1 s 1 -2 ph cm ◆ No significant excess was found for 0.5 steady, orbital modulated or daily basis 0 emission 5 MAXI 2-20keV RXTE-ASM( 10) 3-5keV ÷ 4 ) -2 Swift-BAT( 10) 15-50keV × (cm 3 -1 ◆ Upper limits (ULs) at 95% CL and cts s 2 1 30% systematics using full likelihood 0 method from Aleksic+2012a 30 AMI 15GHz 25 RATAN 4.6 GHz 20 ◆ Assuming power law with Γ =3.2 mJy 15 10 5 0 9 5 − 54500 55000 55500 56000 56500 57000 MJD

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 Discarded IC on surrounding ◆ To avoid absorption: emission outside the corona (> 10 9 cm) IC on stellar photons ◆ Only during HS: most likely @ jets (photon-photon absorption) ◆ Hint of orbital modulation: jet-medium Discarded interaction discarded (< 10 13 cm) -Expected anisotropic inverse Compton on stellar photons: > 10 11 cm IC on thermal photons (photon-photon absorption) 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 VHE new results 7 − 10 ] -1 s -2 BeppoSax HS (Di Salvo et al.,2001) dN/dE [erg cm INTEGRAL-ISGRI HS (Rodriguez et al.,2015) ◆ Jet-medium interaction discarded: not − 8 10 INTEGRAL-PICsIT HS (Zdziarski et al.,2012) Fermi-LAT HS (Zanin et al.,2016) affected by γ - γ absorption MAGIC HS (This work) CTA 50h-sensitivity 9 − CTA 200h-sensitivity 10 2 E Preliminary ◆ @ binary scale less conclusive: 10 − 10 -Transient event, as reported previously, cannot be ruled out (no observations 11 − 10 simultaneously with hard X-ray flare) 12 − -Radio-emitting-blobs during IS (like in 10 Cygnus X-3) 13 − 10 − 14 10 3 5 6 8 9 10 13 15 4 7 11 12 14 10 10 10 10 10 10 10 10 10 10 10 10 10 Energy [eV] 11

A. Fernández-Barral, ICRC 2017, Busan July 12-20 Gamma rays from microquasars Cygnus X-1 and Cygnus X-3 Cygnus X-3: new results at VHE ◆ 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 12

A. Fernández-Barral, ICRC 2017, Busan July 12-20 Gamma rays from microquasars Cygnus X-1 and Cygnus X-3 Cygnus X-3: new results at VHE ◆ Non-negligible absorption, τ ~ σ γγ · n NIR · R, up to R~10 13 cm - assuming σ γγ ~10 -25 cm, L NIR =10 38 erg/s ◆ VHE emission could be related with HE production site (@ binary scales, R>10 11 cm) ◆ Already very constraining ULs: further investigation with Fermi -LAT data 13

A. Fernández-Barral, ICRC 2017, Busan July 12-20 Gamma rays from microquasars Cygnus X-1 and Cygnus X-3 Conclusions ◆ 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 Cygnus X-1 ◆ Probable mechanism anisotropic IC on stellar photons ◆ HE emission site constrained at 10 11 cm < R < 10 13 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 ◆ MAGIC observed Cygnus X-3 covering a radio and HE flare Cygnus X-3 ◆ 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

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