Discovery of VHE Gamma-Ray Emission from the Binary System LMC P3 - PowerPoint PPT Presentation

Discovery of VHE Gamma-Ray Emission from the Binary System LMC P3 Nukri Komin * for the H.E.S.S. Collaboration * Wits University, Johannesburg, South Africa https://www.mpi-hd.mpg.de/hfm/HESS/HESS.shtml

H.E.S.S. Motivation Large Magellanic Cloud in gamma rays  TeV observations with H.E.S.S.  [HESS coll., Science 347:6220 (2015)] N 157B (PWN)  N 132D (SNR)  30 Dor C (superbubble)  MeV/GeV observations with Fermi -LAT optical, 576 – 788 nm (false colour image)  [Fermi coll., A&A 586, A71 (2016)] N 157B, N 132D  Fermi -LAT PSR J0540−6919  LMC P3  LMC P3  unidentified  compatible with 2 SNRs  N. Komin, "VHE emission of the binary LMC P3" 2 ICRC 2017, 2017/07/13, Busan, South Korea.

Motivation LMC P3 is gamma-ray binary  [Corbet et al., ApJ , 829:105 (2016)] blind search for periodic emission  period 10.301 ± 0.002 days  X-ray and radio in anti-phase  binary system  [Seward et al., ApJ , 759:123 (2012)] O5 III(f) companion star  25..42 M ⊙  compact object ?  [Corbet et al. 2016] 6 th gamma-ray binary  SALT only one inside detectable SNR  N. Komin, "VHE emission of the binary LMC P3" 3 ICRC 2017, 2017/07/13, Busan, South Korea.

High Energy Stereoscopic System 5 Imaging Cherenkov Telescopes  record Cherenkov light of air showers  5° field of view (CT 1–4)  100 GeV ... tens of TeV  angular resolution ~0.07°  Namibia → only instrument for TeV observations of  the LMC data presented here: only 4 telescopes  CT5 ignored when present  N. Komin, "VHE emission of the binary LMC P3" 4 ICRC 2017, 2017/07/13, Busan, South Korea.

Data Set optical, 576 – 788 nm (false colour image) LMC observations since 2004  [A. Mellinger, PASP 121, 1180 (2009)] mainly around Tarantula  nebula N 132D  some data on LMC P3  observation time  total 277 h  LMC P3: 100 h  (acceptance corrected) observation conditions  large zenith angle (45° - 52°)  energy threshold ~700 GeV  N. Komin, "VHE emission of the binary LMC P3" 5 ICRC 2017, 2017/07/13, Busan, South Korea.

) 3 0 0 0 0 2 J ( Significant Detection H . E . S . S . - 6 7 ° 1 2 ' n o i t a 2 0 n i l c e D - 6 7 2 4 ' ° 1 0 - 6 7 3 6 ' ° 0 9 0 - 6 7 4 8 ' ° − 1 0 8 0 P S F - 6 8 ° 0 0 ' − 2 0 7 0 h m s h m s 0 5 4 0 0 0 0 5 3 5 0 0 R i g h t A s c e n s i o n ( J 2 0 0 0 ) 6 0 5 0 4 0 3 0 76.3 excess events, 6.4 σ  on = 194, off = 7020 2 0  α = 59.7 1 0  0 0 0 . 0 2 0 . 0 4 0 . 0 6 0 . 0 8 0 . 1 2 2 ( d e g ) θ N. Komin, "VHE emission of the binary LMC P3" 6 ICRC 2017, 2017/07/13, Busan, South Korea.

Folded Light Curve ] 1 − 9 - × 1 0 s 7 . 1 σ 2 - 5 m [ ) V e T 4 1 > ( F 3 2 2 . 5 σ 0 . 7 σ 1 . 0 σ 2 . 4 σ 1 0 0 0 . 2 0 . 4 0 . 6 0 . 8 1 1 . 2 1 . 4 1 . 6 1 . 8 2 o r b i t a l p h a s e folded with 10.301-day orbital period, 0 at GeV maximum  7.1 σ → 6.9 σ post trials  clear phase-locked variability  periodicity search not successful (Lomb-Scargle, zCDF)  N. Komin, "VHE emission of the binary LMC P3" 7 ICRC 2017, 2017/07/13, Busan, South Korea.

Folded Light Curve ] 1 − 9 - × 1 0 s 7 . 1 σ 2 - 5 m [ ) V e T 4 1 > ( F 3 2 2 . 5 σ 0 . 7 σ 1 . 0 σ 2 . 4 σ 1 0 0 0 . 2 0 . 4 0 . 6 0 . 8 1 1 . 2 1 . 4 1 . 6 1 . 8 2 o r b i t a l p h a s e folded with 10.301-day orbital period, 0 at GeV maximum  7.1 σ → 6.9 σ post trials  clear phase-locked variability  periodicity search not successful (Lomb-Scargle, zCDF)  maximum at GeV minimum  N. Komin, "VHE emission of the binary LMC P3" 8 ICRC 2017, 2017/07/13, Busan, South Korea.

Sky Maps ) ) 0 0 3 0 0 0 0 0 2 2 H . E . S . S . H . E . S . S . J J - 6 7 ° 1 2 ' - 6 7 ° 1 2 ' ( ( n n 2 0 o o i i t t a a n n i i - 6 7 2 4 ' - 6 7 2 4 ' l ° l ° c c e e 1 0 D D - 6 7 ° 3 6 ' - 6 7 ° 3 6 ' 0 - 6 7 ° 4 8 ' - 6 7 ° 4 8 ' − 1 0 P S F P S F - 6 8 ° 0 0 ' - 6 8 ° 0 0 ' 2 0 − s s s s h m h m h m h m 0 5 4 0 0 0 0 5 3 5 0 0 0 5 4 0 0 0 0 5 3 5 0 0 R i g h t A s c e n s i o n ( J 2 0 0 0 ) R i g h t A s c e n s i o n ( J 2 0 0 0 ) on peak off peak 0.2 – 0.4 0.4 – 0.2 41.1 excess events, 7.1 σ 35.0 excess events, 3.3 σ (5 ± 1) x 10 35 erg/s <1.2 x 10 35 erg/s (95% CL) N. Komin, "VHE emission of the binary LMC P3" 9 ICRC 2017, 2017/07/13, Busan, South Korea.

Spectrum E n e r g y [ T e V ] 1 1 0 ] V e power-law spectrum T  1 - s no cut-off detection 2 -  1 2 1 0 m c [ 2 E × x u l 1 3 F 1 0 orbit- on-peak averaged 1 4 1 0 index 2.5 ± 0.2 2.1 ± 0.2 ] 4 χ F (>1 TeV) 1.4 ± 0.4 5 ± 2 ∆ [ s l 2 [10 -13 cm -2 s -1 TeV -1 ] a u d i 0 s e L (1 – 10 TeV) 1.4 ± 0.2 5 ± 1 R 2 [10 35 erg s -1 ] 4 1 1 0 E n e r g y [ T e V ] N. Komin, "VHE emission of the binary LMC P3" 10 ICRC 2017, 2017/07/13, Busan, South Korea.

Context 1FGL J1018.6−5856 [HESS, A&A, 577 (2015) A131] 3 . 5 3 . 0 0.35 TeV) 1 ] 2 s − 2 . 5 6 th TeV gamma-ray binary  12 ph cm − 2 . 0 O-type star, no  Flux (E > 1 . 5 circumstellar disk 1 . 0 [10 − → similar to LS 5039  and 0 . 5 1FGL J1018.6−5856 0 . 0 0 . 0 0 . 2 0 . 4 0 . 6 0 . 8 1 . 0 1 . 2 1 . 4 1 . 6 1 . 8 2 . 0 but earlier, giant star  Orbital Phase short peak of emission of  about 20% LS 5039 [HESS, A&A, 460 (2006) 743] ) 4 1 - s as 1FGL J1018.6−5856 n n n n  2 n r o o r o o - n n i i i i r o r 3 . 5 o t o t o t t r o m i o i o r c i c t c r c r r i t t r c s r e n n e n n s s e a e u u u u p a f i p f j j j a j 1 GeV and TeV in anti-phase r u u - p n p n n n n n 3 I I  V e S S o A o o A o P e C C C C T 2 . 5 2 as LS 5039 1 -  0 1 ( 2 ) V e 1 . 5 T 1 ( N E 1 d d 0 . 5 0 0 0 . 2 0 . 4 0 . 6 0 . 8 1 1 . 2 1 . 4 1 . 6 1 . 8 2 O r b i t a l p h a s e N. Komin, "VHE emission of the binary LMC P3" 11 ICRC 2017, 2017/07/13, Busan, South Korea.

Energy Budget by far most luminous gamma-ray binary  10 35 erg/s rather than 10 33 erg/s  pulsar driven?  similar luminosity as pulsar wind nebula N 157B in LMC  PSR J0537-6910 (in N 157B): Ė = 4.9x10 38 erg/s  putative pulsar in LMC P3 needs about the same Ė  would make it top-four luminous pulsar  non-detection of such luminous pulsar may be due to absorption  accretion of stellar wind?  mass loss ~10 -6 M ⊙ /year (~6x10 40 erg/s)  → ~10 -5 of mass loss  N. Komin, "VHE emission of the binary LMC P3" 12 ICRC 2017, 2017/07/13, Busan, South Korea.

Light Curve light curve driven by shape of orbit  conjunctions  MeV/GeV and TeV emission is inverse  Compton emission IC production favoured in head-on collisions  → gamma-ray maximum at superior  conjunction gamma-gamma absorption disfavoured in  tail-on collisions → TeV maximum at inferior conjunction  periastron  MeV/GeV emission is synchrotron of highly  relativistic electrons ] 1 − 9 - 1 0 × periastron: cooling increased, s 7 . 1 σ  2 - 5 m [ electron cut-off energy reduced ) V e T 4 1 → MeV/GeV minimum at periastron > (  F 3 high-density stellar photon field  2 2 . 5 σ 0 . 7 σ 1 . 0 σ 2 . 4 σ → TeV IC emission maximum at  1 periastron 0 0 0 . 2 0 . 4 0 . 6 0 . 8 1 1 . 2 1 . 4 1 . 6 1 . 8 2 o r b i t a l p h a s e N. Komin, "VHE emission of the binary LMC P3" 13 ICRC 2017, 2017/07/13, Busan, South Korea.

Summary LMC P3 6 th gamma-ray binary  similar to LS 5039 and 1FGL J1018.6−5856  most luminous: 10 35 erg/s  requires highly luminous pulsar or strong stellar wind  observations and understanding of many different binaries needed to  understand underlying acceleration mechanism orbital parameters? → optical observations  emission during off-peak? → Cherenkov Telescope Array  ) ) 0 0 3 0 0 0 0 0 2 2 H . E . S . S . H . E . S . S . J J - 6 7 ° 1 2 ' - 6 7 ° 1 2 ' ( ( n n 2 0 o o i i t t a a n n i i - 6 7 2 4 ' - 6 7 2 4 ' l ° l ° c c e e 1 0 D D - 6 7 ° 3 6 ' - 6 7 ° 3 6 ' 0 - 6 7 ° 4 8 ' - 6 7 ° 4 8 ' 1 0 − P S F P S F - 6 8 0 0 ' - 6 8 0 0 ' ° ° − 2 0 s s s s h m h m h m h m 0 5 4 0 0 0 0 5 3 5 0 0 0 5 4 0 0 0 0 5 3 5 0 0 R i g h t A s c e n s i o n ( J 2 0 0 0 ) R i g h t A s c e n s i o n ( J 2 0 0 0 ) N. Komin, "VHE emission of the binary LMC P3" 14 ICRC 2017, 2017/07/13, Busan, South Korea.