MAGIC RESULTS ON BINARY SYSTEMS Roberta Zanin (UB-ICC) on behalf of the MAGIC collaboration

the MAGIC telescopes 2

  in La Palma (Canary islands) at 2200 m asl   stereoscopic since Fall 2009   55 GeV (trigger) energy threshold   sensitivity 0.8% Crab flux

in 50 hrs

Outlook 3

  Introduction   Results on gamma-ray binaries

 HESS J0632+057  LS I +61° 303

  Results on microquasars  Cygnus X-3  Scorpius X-1

Wind/wind or jet? 4

F. Mirabel, Science 312 F. Mirabel, Science 312, 2006

GAMMA-RAY BINARIES

HESS J0632+057: a new binary

HESS point-like source variable at TeV X-ray variability and periodicity P = 321 days

coincident with Be star MWC 148

radio extension 30 days after X-ray outburst

6

Moldon et al., A&A, 2011

Bongiorno et al., ApJ, 2011 Aharonian et al., A&A, 2007 Acciari et al., ApJ, 2009

HESS J0632+057: back in Feb. 2011

  increase in the X-ray flux detected by Swift/XRT on Jan.28, 2011 with a peak (factor 3) on Feb. 6, 2011

  significant VHEγ-ray during the X-ray peak by both MAGIC and VERITAS

7

Swift/XRT

Aleksić et al., ApJ, 2012

HESS J0632+057: MAGIC detection

  Oct. 2010-Mar.2011: 10.6 h

  detected only in Feb.2011 ~6σin 5.6 h at ΔΦ=0.3 after periastron

  at 4% Crab flux level (as for previous observations)

  power-law spectrum Γ = 2.6 ± 0.3 ± 0.3

  correlation with X-rays? cannot be proven statistically Aleksić et al., ApJ, 2012

8

LSI +61° 303

•  Be star + unknown compact object •  distance 2 ± 0.2 kpc •  eccentricity e =0.54 •  periodic with P = 26.496 days

complex radio morphology coupled with orbital period in favor of wind/wind interaction

X-ray variability in orbital profiles

9

Moldon, 2012

LSI +61° 303: at VHE

discovered by MAGIC in 2006 as a variable TeV source above 400 GeV: peak at ϕ=0.6-0.7 @ 15% Crab flux

10

Albert et al., Science, 2006

LSI +61° 303: at VHE

discovered by MAGIC in 2006 as a variable TeV source: peak at ϕ=0.6-0.7 @ 15% Crab flux

11

Albert et al., ApJ, 2009 Albert et al., Science, 2006

LSI +61° 303: at VHE

discovered by MAGIC in 2006 as a variable TeV source above 400 GeV: peak at ϕ=0.6-0.7 @ 15% Crab flux

TeV periodicity P=26.5 days

12

Crab-like spectrum

Albert et al., ApJ, 2009

Albert et al., Science, 2012

13

  s

LSI +61° 303: in a multi-wavelength context TeV – X-rays correlation

no radio-TeV correlation

however VERITAS found no such correlation for a different orbit

Anderhub et al., ApJ, 2009

14

  ~50 hrs between Oct.2009-Jan.2010

  overall detection at 6σ   flux variability within

cycles: flux a factor 10 lower than what previously detected at Φ=0.6-0.7

  variable emission peaking at different phases: Φ=0.6-0.7 & Φ=0.9-1

periodicity gone? not possible to tell

LSI +61° 303: much more on TeV variability

Aleksić et al., ApJ, 2012

15

  no spectral variability observed

same process at work   less efficient? due to changes

in the stellar wind density (visible at other wavelengths?)

  more absorption (where the spectral features?)

LSI +61° 303: much more on TeV variability

  in Fall 2010, source is back to 15% Crab-level flux at Φ=0.6-0.7

Γ=2.5±0.6±0.7

Aleksić et al., ApJ, 2012

MICROQUASARS

Cygnus X-3 17

  Wolf-Rayet companion star (HMXB)   distance ~7 kpc   short orbital period of 4.8 hrs   relativistic jets MQ

  X-ray spectral states resemble the canonical states of the BH MQs: soft and hard states

Szostek & Zdziarski 2004

hard state

soft state

Cygnus X-3: at high-energies 18

  Fermi/LAT observed a 29σ signal above 100 MeV in two periods of high activity: MJD 54750-54820 and 54990-55045

HE active periods coincide with the soft state   AGILE detected HE emission above 100 MeV as flaring emission

Oct. 2008 Dic. 2008 Jun. 2009 Jul. 2009

Cygnus X-3: at VHE 19

  56 hrs between Mar. 2006 and Aug. 2009 (MAGIC single telescope)

  no VHE signal found above 250 GeV F (E > 250 GeV) < 2.2 x 10-12 photons cm-2 s-1

(1.3% Crab flux) @95% CL

  phase-folded analysis yielded no significant signal Aleksić et al., ApJ, 2010

Cygnus X-3: MAGIC observations 20

[% C

rab

units

]-12

F(E>

250

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)x10

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-2[p

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m

-6F(

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ount

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Radi

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x de

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[Jy]

Time [MJD]

cycle I cycle II cycle III cycle IV cycle V

0

20

40

60

80MAGIC

0

10

20

30

40

50

0

1

2

3AGILE

Fermi/LAT

0

0.05

Swift/BAT

0

5

10

15 RXTE/ASM

53800 54000 54200 54400 54600 54800 55000 55200

-210

-110

1

10RATAN 2.15 GHzRATAN 4.8 GHzRATAN 11.2 GHz

RT / AMI 15 GHzOVRO 15 GHz

Aleksić et al., ApJ, 2010

Cygnus X-3: simultaneously to HE detection 21

  Fermi/LAT above 100 MeV   average flux: 1.2x10-6 ph.cm-2s-1

  Γav = 2.7 ± 0.05 ± 0.20

  peak flux > 2x10-6 ph.cm-2s-1

  AGILE above 100 MeV   peak flux 1.9x10-6 ph.cm-2s-1

  Γ = 1.8 ± 0.2

  MAGIC ULs still compatible with the extrapolation of a power-law with Γav = 2.7, but not with the extrapolation of AGILE’s one (Γ=1.8)

Aleksić et al., ApJ, 2010

Conclusions on Cygnus X-3 22

  Non-detection of Cygnus X-3 at VHE: ULs at 1.3% crab flux above 250 GeV

  No VHE signal either from persistent (hard state) or transient (soft state) jets

  No VHE detection during the period of enhanced activity in the GeV band

Scorpius X-1 23

  neutron star and M-type star

  distance 2.8 ± 0.3 kpc

  circular orbit with P=0.787 days

  radio relativistic jets

Z-type LMXB:   X-ray intensity and color variability   X-ray spectral states based on the

color-color diagram (CCD)

Migliari & Fender, MNRAS, 2006

Scorpius X-1 24

  neutron star and M-star   distance 2.8 ± 0.3 kpc   circular orbit with

P=0.787 days

  more double banana than Z-track

  X-ray spectral states have no orbital dependence

  radio emission & non-thermal X-ray tail in the HB

NORMAL BRANCH

Z-type LMXB:   X-ray intensity and color variability   X-ray spectral states based on the

color-color diagram (CCD)

FLARING BRANCH

HORIZONTAL BRANCH

Di Salvo et al., ApJ, 2006

Scorpius X-1: MAGIC/RXTE observations 25

  simultaneous campaign with MAGIC and RXTE/PCA in May 2010

  8 hrs spread in 6 nights

  X-ray data used to define X-ray spectral states (soft/hard colors follow definition in D’Ai et al 2007)

  3 nights in the HB

  no detection at VHEs above 300 GeV when in HB: F(E>300 GeV) < 3.4 x 10-12 photons cm-2 s-1 @ 95% CL

(2.7% Crab flux)

Aleksić et al., ApJ, 2011

Conclusions on Scorpius X-1 26

  MAGIC did not detect Sco X-1 above 300 GeV

  No Sco X-1 detection even in the HB state (where non-thermal emission has been detected in other wavelengths)

  The ULs to the VHE integral flux set ULs to the VHE luminosity to jet power ratio: LVHE/Ljet < 10-3

Conclusions 27

  MAGIC was successfully detecting the two known gamma-ray binaries which are visible on the Northern hemisphere: LS I °61+303 and HESS J0632+057.

  Discovery of LS I °61+303 in 2006 followed by several campaigns: VHE periodicity, possible correlation between X-ray and VHE, no VHE-radio correlation, intra-cycle variability...

  HESS J0632+057 detected simultaneously to Feb. 2011 X-ray outburst at 4% Crab flux level above 200 GeV

  MAGIC did not detected any VHE signal from well-established microquasars

  Cygnus X-3 did not show VHE emission above 250 GeV either in soft or in hard state, or during the period of high-activity in the high-energy band

  MAGIC did not detect Scorpius X-1 above 300 GeV during the HB state (where non-thermal X-ray emission has been detected).