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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

3115 results found.

  1. IceCube-200926A: No Candidate Counterparts from the Zwicky Transient Facility
  2. IceCube Alert 200926.33: Global MASTER-Net observations report
  3. Fermi GRB 200925A: Global MASTER-Net observations report
  4. Fermi GRB 200924A: Global MASTER-Net observations report
  5. Fermi GRB 200923A: Global MASTER-Net observations report
  6. IceCube Alert 200921.80: Global MASTER-Net observations report
  7. GRB 200922A: Swift/UVOT Detection
  8. IceCube-200921A: no significant detection in HAWC observations
  9. Fermi GRB 200922B: Global MASTER-Net observations report
  10. GRB 200922A: LCO observations
  11. GRB 200920A: Fermi GBM Final Real-time Localization
  12. Fermi GRB 200919C: Global MASTER-Net observations report
  13. Fermi GRB 200919B: Global MASTER-Net observations report
  14. IceCube-200916A: Two Candidate Counterparts from the Zwicky Transient Facility
  15. IPN triangulation of GRB 200916B (short)
  16. IceCube Alert 200914.00: Global MASTER-Net observations report
  17. IPN triangulation of GRB 200907A (short)
  18. Fermi GRB 200908A: Global MASTER-Net observations report
  19. Fermi GRB 200907C: Global MASTER-Net observations report
  20. GRB 200906A: Nanshan/NEXT optical upper limit
  21. Fermi GRB 200903B: Global MASTER-Net observations report
  22. GRB 200901A: Fermi GBM observation
  23. GRB 200901A: Swift detection of a burst
  24. GRB 200829A: Koshka Zeiss-1000 optical observations
  25. Fermi trigger No 620402299: Global MASTER-Net observations report
  26. Zwicky Transient Facility discovery of ZTF20abtxwfx/AT2020sev, a fast optical transient and candidate afterglow
  27. IPN triangulation of GRB 200826B
  28. GRB200826A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 620108997)
  29. IPN triangulation of GRB 200815A (short)
  30. GRB 200819A: Kitab, TSHAO optical upper limit
  31. Fermi GRB 200817A: Global MASTER-Net observations report
  32. GRB 200817A: Fermi GBM Final Real-time Localization
  33. Fermi trigger No 619270776: Global MASTER-Net observations report
  34. Fermi GRB 200803A: Global MASTER-Net observations report
  35. Fermi GRB 200802A: Global MASTER-Net observations report
  36. GRB 200802A: Fermi GBM Final Real-time Localization
  37. Fermi GRB 200801A: Global MASTER-Net observations report
  38. Swift Detection of an SGR-like flare from AX J1846.4-0258
  39. Swift GRB200801.84: Global MASTER-Net observations report
  40. Fermi GRB 200716A: Global MASTER-Net observations report
  41. GRB 200716C: Swift detection of a burst with an optical counterpart
  42. Fermi GRB 200714D: Global MASTER-Net observations report
  43. Fermi GRB 200714A: Global MASTER-Net observations report
  44. Fermi trigger No 616370565: Global MASTER-Net observations report
  45. Update of alert from the HAWC Burst Monitor HAWC-200709A
  46. Fermi GRB 200705A: Global MASTER-Net observations report
  47. Trigger 980513: Swift detection of SGR Swift J1818.0-1607
  48. GRB 200630A: Swift detection of a burst
  49. Fermi GRB 200626A: Global MASTER-Net observations report
  50. IceCube-200620A: One Candidate Counterpart from the Zwicky Transient Facility
  51. LIGO/Virgo MS200618aq: Retraction of a test binary neutron star candidate
  52. Fermi trigger No 614103490: Global MASTER-Net observations report
  53. Baksan Neutrino Observatory Alert 200617.47: Global MASTER-Net observations report
  54. GRB 200616B: Fermi GBM Final Real-time Localization
  55. GRB 200615B: MAXI/GSC detection
  56. Baksan Neutrino Observatory Alert 200614.34: Global MASTER-Net observations report
  57. GRB 200614A: Fermi GBM Final Real-time Localization
  58. Swift GRB200612.19: Global MASTER-Net OT detection
  59. Swift GRB200612.19: Global MASTER-Net observations report
  60. Fermi GRB 200604A: Global MASTER-Net observations report
  61. Baksan Neutrino Observatory Alert 200603.12: Global MASTER-Net observations report
  62. GRB 200529A: MITSuME Akeno optical upper limits
  63. Fermi GRB 200601A: Global MASTER-Net observations report
  64. IceCube-200530A: Candidate Counterparts from the Zwicky Transient Facility
  65. Swift GRB 200528A: Global MASTER-Net observations report
  66. GRB 200524A: CrAO optical observations
  67. GRB 171205A: ATCA observations of late-time radio emission
  68. Fermi GRB 200522B: Global MASTER-Net observations report
  69. GRB 200522B: Fermi GBM Final Real-time Localization
  70. Fermi trigger No 611676654: Global MASTER-Net observations report
  71. GRB 200519A: Swift detection of a burst with an optical afterglow
  72. Fermi trigger No 611434353: Global MASTER-Net observations report
  73. GRB 200517A: MAXI/GSC detection
  74. GRB 200514B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 611140062) - More Candidates
  75. GRB 200514A: MITSuME Akeno optical upper limits
  76. GRB200514B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 611140062)
  77. IceCube-200512A: No Candidate Counterparts from the Zwicky Transient Facility
  78. Konus-Wind observation of SGR 1935+2154 activity on 2020 May 10
  79. GRB 200509A: Swift detection of a burst with a possible optical counterpart
  80. Insight-HXMT X-ray and hard X-ray upper limits to the radio burst detected by FAST from SGR 1935+2154
  81. Fermi GBM trigger 200429866/609886052 is not a GRB
  82. Konus-Wind observation of hard X-ray counterpart of the radio burst from SGR 1935+2154
  83. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  84. IceCube-200425A: No significant detection in HAWC
  85. GRB 200423A: Fermi GBM Final Real-time Localization
  86. Fermi GRB 200421A: Global MASTER-Net observations report
  87. GRB 200421A: Fermi GBM Final Real-time Localization
  88. Fermi trigger No 608935505: Global MASTER-Net observations report
  89. GRB 200415A: MASTER imspection and possible localisation
  90. GRB 200416A: Swift detection of a burst with an optical afterglow
  91. Konus-Wind observation of GRB 200412A
  92. Baksan Neutrino Observatory Alert 200408.26: Global MASTER-Net observations report
  93. Swift GRB 200409A: Global MASTER-Net observations report
  94. Fermi GRB 200407A: Global MASTER-Net observations report
  95. Baksan Neutrino Observatory Alert 200406.3: Global MASTER-Net observations report
  96. Fermi GRB 200405A: Global MASTER-Net observations report
  97. Fermi GRB 200403B: Global MASTER-Net observations report
  98. Fermi GRB 200403A: Global MASTER-Net observations report
  99. Fermi GRB 200402C: Global MASTER-Net observations report
  100. Fermi GRB 200401A: Global MASTER-Net observations report

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