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Yuna Dan Mieko Takamura Momotaro Nakamura Masaaki Murata Spring School 2018 March 10 2018/3/10 1 Index 1.Introduction 2.How to analyze 3.Result 4.Discussion


  1. ����� ������ ����������� Yuna Dan Mieko Takamura Momotaro Nakamura Masaaki Murata Spring School 2018 March 10 2018/3/10 1

  2. Index 1.Introduction 2.How to analyze 3.Result 4.Discussion 5.Summary 2018/3/10 2

  3. 1.Introduction 2018/3/10 3

  4. Neutron stars • Typical radius: 10 km • Typical mass: 1 solar mass • Density:10 17 kg/m 3 • Magnetic field: 10 4 – 10 11 T Credit: NASA Neutron stars are really extreme objects! Credit: NASA’s Goddard Space Flight Center 2018/3/10 4

  5. Pulsar • Very fast rotating neutron stars • Extraction and acceleration of particles by the powerful magnetic field • Production of pulsed electromagnetic emission • Loss of energy due to radiation emission: rotational spindown 2018/3/10 5

  6. We analyze THE CRAB VELA GEMINGA 964 Age (Supernova in ~10.000 ~300.000 [years] 1054 A.D.) Distance ~7180 ~960 ~800 [ly] Rotational period ~33 89 237 [ms] Credit: JAXA Credit: NASA Credit: NASA 2018/3/10 6

  7. The Fermi Gamma-ray Space Telescope • Mission type: Gamma-ray observatory • Launch date: 11 June 2008, 16:05 UTC • Atitude: 525.9 - 543.6 km • Period: 95.33 min It is the most sensitive gamma-ray observatory in orbit! 2018/3/10 7

  8. What’s phaseogram? • Phaseogram: Sum up events that happen at the same phase • Phase: Physical information on the pulsar! 2018/3/10 8

  9. Our mission 1. Learn about pulsar, Fermi, the way to analyze and etc… 2. Produce a phaseogram 3. Decide frequencies and frequencies derivatives 4. Analyze something strange 2018/3/10 9

  10. 2.How to analyze 2018/3/10 10

  11. How to analyze Make The Count Map Download selection of of Each Data exact The Crab, photons VELA and Geminga Energy -43:00:00.0 range -45:00:00.0 300 � 30000MeV 45:00.0 40:00.0 35:00.0 30:00.0 25:00.0 5 0 : 0 0 . 0 20:00.0 55:00.0 15:00.0 9:00:00.0 8 : 1 0 : 0 0 . 0 2018/3/10 11 0 187 374 563 750 939 1126 1313 1502 1689 1876

  12. How to get data Fermi LAT What can we get? � The direction from which photons come. � To measure amount of energy of one photon. 2018/3/10 12

  13. How to define the time • What should we think about to define the correct time: • → Barycentric Collection 2018/3/10 13

  14. 3.Result 2018/3/10 14

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  22. ��4��482��6���42�41�68��� Observation Time is for a bout 10 Year !! �4�68�1 �����(����� � �����.1��� ��4��4 82�� ���0 �.�) 2018/3/10 22

  23. �������2�����3�2��0������ (�01 ������0��� � �������7������ ������ �2�� .��� �-�) 2018/3/10 23

  24. )������3�������3��1������ .�81 �����-����� � ������)�2�� )������3�� ���0 ���( 2018/3/10 24

  25. �������������71������� )�12 �����(���� � ����� ������ ���� ���0 MJD 58051~60 MJD 58061~70 �.-� MJD 58071~ 80 2018/3/10 25

  26. �������������������� � MJD 58071~ 80 2018/3/10 26

  27. 4.Discussion 2018/3/10 27

  28. Chi-Square test • Evaluation of deviation between experimental data and model x x i Event number • N: Number of bins • x i : Counts of photons (experimental data) • X: Counts of photons (model data) 0 1 ��� i N ��� Number of bins 2018/3/10 28

  29. Statistical test of pulsation ! " ~1 ! " ≫ 1 Count of photons Count of photons ↑Model 0 1 Phase Phase 2018/3/10 29

  30. How to fit We tried to know when the event happened with chi square statistics. We discovered the edge in graph. →It is possible that at this time, the event occurred. 2018/3/10 30

  31. Decide when the event happened We investigated the edge’s time by changing two line. →The event happened at “58064.503 � 0.066”. 2018/3/10 31

  32. Compare with other wave area We checked “The Jodrell Bank Observatory with the 42-ft Lovell Telescope(1400 MHz)” . Reference: Shaw+2017(Atel#10939) →The event happened at 58064.555(3)(MJD) (58064.503(66)) https://en.wikipedia.org/wiki/Lovell_Telescope#/media/File:Lovell_Telescope_5.jpg ⇒ The two data are consistent within a statistical error. 2018/3/10 32

  33. What was the event? We discovered the two things. 1. The gamma ray from the Crab pulsar changed and the time is consistent in two wave areas. 2. The pulsar’s frequency increased after the event. ⇒ We expected that the event was “GLITCH”. 2018/3/10 33

  34. What is happened on the CRAB? • We think … STARQUAKE!!!! Starquake on the CRAB. • If we assume that the preservation of angular moment is valid… ∆" " ∼ ∆$ ≒ 10km $ ∆" =5 � 10mm Sedimentation 2018/3/10 34

  35. 5.Summary 2018/3/10 35

  36. How much did the frequency change? We investigated how much the frequency changed. →The frequency increased by 14μHz. Question? : We need more study !! ? 2018-01-02 2018/3/10 36

  37. We made a histogram of Δν/ν. It shows that the Glitch we discovered is the biggest one. JODRELL BANK 2018/3/10 37 Log 10 ( ∆"/"×10 ' )

  38. 0.01m Sedimentation 2m Uplift Radius of neutron star Earth radius ≒ 10 6 m ≒ 10 4 m Magnitude = 9.0Mw Magnitude = 23.5Mw 2018/3/10 38

  39. Thank you for your attention 2018/3/10 39

  40. Back up 2018/3/10 42

  41. ������ delta_nu v.s. MJD 2018/3/10 43

  42. ��������� ������������� Cumlative chi2 v.s. MJD 2018/3/10 44

  43. �������������� Glitch recovery (exponential decay in nu- MJD plot) 2018/3/10 45

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