VHE Gamma-Ray Observations of Binary Systems with the MAGIC Telescopes

TeV Particle Astrophysics 2016 CERN, 12-16 Sept 2016

VHE gamma-ray observations of binary systems with the MAGIC telescopes

A. Fernández-Barral

W. Bednarek, O. Blanch, J. Cortina, E. de Oña, D. Hadasch, R. López-Coto, A. López-Oramas, E. Moretti, P. Munar-Adrover, J. M. Paredes, M. A. Pérez- Torres, M. Ribó, J. Sitarek, D. F. Torres and R. Zanin on behalf of the MAGIC Collaboration VHE gamma-ray observations of binary systems with the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 Sept 2016

The MAGIC telescopes

• Stereoscopic system of two 17 m diameter IACTs @ La Palma (Canary Islands)

MAGIC

2004-2009→ Stand-alone MAGIC I

2009→ Construction of MAGIC II

2011-2012→ Major upgrade

2 VHE gamma-ray observations of binary systems with the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 Sept 2016

The MAGIC telescopes

• Integral sensitivity: Stereoscopic mode: 0.67±0.04% Crab Nebula ﬂux (E>290 GeV) in 50 h Stand-alone mode: 1.60±0.03% Crab Nebula ﬂux (E>280 GeV) in 50 h

Aleksić et al. DOI: 10.10161

3 VHE gamma-ray observations of binary systems with the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 Sept 2016

MAGIC observations on binary systems

Gamma-ray binaries X-ray binaries

Cygnus X-1 MWC 656 LS I +61 303 V404 Cygni

Cataclysmic variables

AE Aquarii V339 Del ASASSN-13ax YY Her 4 VHE gamma-ray observations of binary systems with the MAGIC telescopes CataclysmicA. Fernández-Barral, variablesTeVPA, CERN 12-16 Sept 2016

5 VHE gamma-ray observations of binary systems with the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 Sept 2016

Cataclysmic variables

• Classical novae: WD + companion star ﬁlling Roche lobe (late-type for Symbiotic novae) • @ GeV regime: 5 novae detected by Fermi/LAT • Particle acceleration: Leptons (GeV component)→ IC of accelerated e- in the shock on stellar photons (symbiotic) or interstellar medium (classical)

Hadrons (TeV component)→ p-p interaction with stellar wind (symbiotic) or internal shock (classical)

• MAGIC observations: V339 Del (Classical nova) ASASSN-13ax (Dwarf nova) External trigger YY Her (Symbiotic nova) AE Aquarii (nova-like cataclysmic variable) MW campaign

6 VHE gamma-ray observations of binary systems with the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 Sept 2016

Novae & dwarf nova observations Ahnen et al. (MAGIC), A&A 582 (2015) 67

4 4.5 V339 Del • ASASSN-13ax & YY Her: No detection 5 5.5 V Magnitude • V339 Del: 6 6.5 7 ▶︎ Optical outburst in August 16 2013 (V~5 mag) 7.5 ▶︎ Detected @ GeV (Fermi/LAT data) 8 56515 56520 56525 56530 56535 56540 56545 56550 ▶︎ MAGIC observed 8 nights for 11.6 hrs: No detection MJD ×10-6 V339 Del, Fermi-LAT ] 0.7 -1 1 day binning U.L. s

-2 0.6 3 day binning U.L.

] -10 -1 10 0.5 s -2 ASASSN-13ax 0.4 0.3 10-11 0.2

dN/dE [TeV cm dN/dE [TeV 0.1 2 E Flux > 100 MeV [ph cm

] -10 0 -1 10 56515 56520 56525 56530 56535 56540 56545 56550 -12 s MJD 10 -2 YY Her

MAGIC ] -1 s Fermi-LAT -2 10-11 10-13 10-11 -1 2 3 10 1 10 10 10 cm dN/dE [TeV 2

E [GeV] E

10-12 MAGIC 10-12 Fermi-LAT Flux > 300 GeV [ph cm 56515 56520 56525 56530 56535 56540 56545 56550 10-13 MJD 10-1 1 10 102 103 E [GeV] 7 VHE gamma-ray observations of binary systems with the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 Sept 2016

Novae modeling (V339 Del) Ahnen et al. (MAGIC), A&A 582 (2015) 67

• Combination of GeV and TeV observations to limit Lp/Le:

▶︎GeV component: IC with nova photosphere ▶︎Modiﬁed Sitarek & Bednarek model: ▶︎TeV component: Expected p-p (shock+ejecta)

▶︎Evaluation of the photon ﬁeld with optical and UV parameters→ Ep and Ee → Protons up to ~1.6 TeV expected

▶︎ Assumed power-law Γ=1.5 & cut oﬀ @ Ee and Ep=> Lp ≲ 0.15Le

] -9.5 -2 -1.5 -Ee/10 GeV -1.5 -Ep/1.6 TeV dNe/dE∝ E × e , dN /dE∝ E × e , L =0.10Le cm e p p p -1 -10

-10.5 Photosphere par. from: Metzger et al. (2015) dN/dE ) [erg s 2 -11 log (E -11.5

-12

-12.5

-13 -1 0 1 2 3 4 5 log (Energy / GeV) 8 VHE gamma-ray observations of binary systems with the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 Sept 2016

AE Aquarii Aleksić et al. (MAGIC), A&A 568, A109 (2014)

• WD (T=33.08 s)+ red giant, orbital 11 KVA Skinakas period 9.88 hr Vidojevica 11.5 •

Flares 50% of its time in optical, radio B [mag] 12 and soft and hard X-rays 12.5

• Dubious gamma-ray detection in the 1

] 0.8 Swift -1 90s (observed by Whipple, MAGIC and 0.6 H.E.S.S.) 0.4

• Aim: Conﬁrm or rule out gamma-ray 0.2 XRT [counts s emission within a MWC

] Upper limit above 200 GeV -1

s -10 Upper limit above 1 TeV -2 10

10-11

-12

10VHE Flux [cm

65 70 75 80 85 90 95 100 MJD-56000 9

MJD-56000 VHE gamma-ray observations of binary systems with the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 Sept 2016

AE Aquarii Aleksić et al. (MAGIC), A&A 568, A109 (2014)

• No detection in steady (12 hr) or daily 11 KVA Skinakas basis analysis Vidojevica 11.5 •

Flux UL at the same level B [mag] 12 independently of the source state→ No 12.5 correlation 1

• ] 0.8 Swift

ULs below model predictions -1 0.6 and previous detections 0.4 • Ejection WD model consistent 0.2 with ULs→ CTA XRT [counts s

] Upper limit above 200 GeV -1

s -10 Upper limit above 1 TeV -2 10

10-11

-12

10VHE Flux [cm

65 70 75 80 85 90 95 100 MJD-56000 10

MJD-56000 VHE gamma-ray observations of binary systems with the MAGIC telescopes X-rayA. Fernández-Barral, binaries TeVPA, CERN 12-16 Sept 2016

jets companion star (microquasars)

corona

compact object accretion disk

11 VHE gamma-ray observations of binary systems with the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 Sept 2016

Cygnus X-1 Paper in preparation

• One of the brightest HMXBs: ~15 M⊙ O9.7 Iab + 25-35 M⊙ BH, P = 5.6 d, d=1.86 kpc • @ HE: ▶︎ TS=16 in the HS with 3.8 yr of Fermi/LAT data (Malyshev et al. 2013) -6 -2 -1 ▶︎ Three 1-2 d ﬂaring events with an integral ﬂux 2x10 cm s for E>100 MeV by AGILE (Sabatini et al., 2010, 2013; Bulgarelli et al. 2013) ▶︎ 4σ hint in ~80 min for E>150 GeV with the MAGIC telescopes (Albert et al. 2007)

▶︎ High-signiﬁcance detection (TS=53) for E between 60 MeV and 500 GeV with 7.5 yrs of Fermi/LAT data (Zanin et al. 2016)

(Zanin et al. 2016) Detection only in HS

Hint of orbital modulation (detection @ 0.75-0.25) → If conﬁrmed, anisotropic IC on stellar photons

No daily variability found

Spectrum power-law with Γ=(2.3±0.1) up to ~20 GeV 12 VHE gamma-ray observations of binary systems with the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 Sept 2016

Cygnus X-1: MAGIC observations Paper in preparation

• ~98 hr between 2007 June and 2014 September

• Steady emission: No detected

• Daily basis analysis: No detection or hint • Search in HS & SS:

▶︎~84 hr in HS & ~14 hr in SS + phase-folded analysis

▶︎No evidence of detection @ any X-ray spectral state or phase

• TeV emission cannot be discarded:

▶︎Interaction jets + ISM

▶︎Hadronic origin

▶︎Flare

13 VHE gamma-ray observations of binary systemsISGRI with LC 18-60 the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 SeptISGRI 2016 LC 60-300 18th 19th 20th V404 Cygni Paper in preparation

• LMXB 9-15 M⊙ BH + ~0.7 M⊙ K3 III, P=6.5d, d=2.39±0.14 kpc

• Major outburst in June 2015 26th 27th (quiescent since 1989)

• MAGIC observations triggered by INTEGRAL:

▶︎Observed in GRB mode

▶︎From June 18 to 27 for ~11 hr

▶︎Dedicated bayesian blocks selection upon INTEGRAL data → 7 hr with an overall 0.08σ

UL of 4.8x10-12 cm-2s-1(E=150-950 GeV)

14 VHE gamma-ray observations of binary systems with the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 Sept 2016

MWC 656 Aleksić et al. (MAGIC), A&A 576, A36 (2015)

• From optical spectroscopy classified as the first BH + Be star system (Casares et al. 2014) • P=60.37±0.04 d, d=2.6±0.6kpc • Gamma-ray detection by AGILE in July 2010 (Lucarelli et al. 2010) • Observed 21.3 hr in stand-alone mode (2012) and 3.3 hr in stereoscopic mode (2013). No steady or periodic detection: Integral UL of 2.0x10-12 -2 -1 cm s (E>300 GeV, Γ=2.5) 39 10 Radio EVN, 2011 January-February X-ray, 2013 June 37 AGILE, 2010 July ▶︎Differential ULs from 245 GeV to 6.3 10 ] Fermi/LAT, 2010 July 1 35 TeV, Γ=2.5 (2013 campaign) − 10 Fermi/LAT, 3.5 years MAGIC, 2013 June 1033

1031

dF/dE [ erg s 29 2 10 E 1027

1025 10−6 10−4 10−2 100 102 104 106 108 1010 1012 E[eV] 15 VHE gamma-ray observations of binary systems with the MAGIC telescopes Gamma-rayA. Fernández-Barral, binaries TeVPA, CERN 12-16 Sept 2016 VHE gamma-ray observations of binary systems with the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 Sept 2016

LS I +61º 303 Ahnen et al. (MAGIC), A&A 591, A76 (2016)

• Be star with circumstellar disk + NS or BH

• Discovered @ TeV by MAGIC (Albert et al. 2006) ; followed-up by MAGIC and VERITAS

• Eccentricity of 0.54±0.03, P=26.4969(28) d, Φper=0.23±0.03

• Periodic outburst @ 0.5-0.75, sporadic emission @ 0.75-1.0 (once seen by VERITAS @ 0.081)

• Superorbital variability of 1667±8d (optical, radio and HE)

• Unknown nature of VHE emission→ ﬂip-ﬂop magnetar model (Torres et al. 2012)

▶︎Could explain Superorbital variability

▶︎Expected anticorrelation between Size of the disk and VHE emission

17 VHE gamma-ray observations of binary systems with the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 Sept 2016

LS I +61º 303 Ahnen et al. (MAGIC), A&A 591, A76 (2016)

] 40 -1 MAGIC s 17 -2 35 VERITAS Nightly 16 cm Constant Contemporary -12 30 Sinusoidal 15 Step function 14 Simultaneous 25 13 12 20 EW [A] 11 15 10 10 9 8 5

0 850

Integral Flux Peak (E>300 GeV) [10 −5 800 −10 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 750 Superorbital Phase

FWHM [km/s] 700 ▶︎Superorbital signature found @ TeV 650 compatible with radio 40

▶︎Monitoring program MAGIC + VERITAS 30

on going 20 10

0 ▶︎No (anti-)correlation found vel Halpha [km/s] −10

▶︎Diﬀerent timescales between optical −20 0 2 4 6 8 10 18 and TeV might blur its existence TeV flux (E>300GeV) [10-12 cm-2 s-1] VHE gamma-ray observations of binary systems with the MAGIC telescopes A. Fernández-Barral, TeVPA, CERN 12-16 Sept 2016

Summary

• MAGIC performed a dedicated running program to detect Cataclysmic variables (V339 Del, YY Her, ASASSN-13ax and AE Aquarii)

▶︎ No detection in the TeV regime ▶︎ Modeling classical novae through V339 Del ▶︎ Most stringent ULs on AE Aquarii with the current instruments

• Deep observations of X-ray binaries: ▶︎ No detection of Cygnus X-1 at TeV energies: ULs for steady, daily and separated X-ray states (including phase-folded analysis) ▶︎ ULs on the LMXB V404 Cygni during the June 2015 outburst ▶︎ ULs on the ﬁrst known Be+BH binary, MWC 656

• Study of gamma-ray binaries: ▶︎ Long-term campaign of LS I 61º +303: superorbital modulation found at TeV. On-going campaign with VERITAS

19 TeV Particle Astrophysics 2016 CERN, 12-16 Sept 2016 Thank you

A. Fernández-Barral