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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"

2722 results found.

  1. GRB 201013A: TSHAO and AbAO optical observations, afterglow confirmation
  2. GRB 201013A: FRAM-ORM possible afterglow candidate
  3. IceCube-201007A: No candidate counterparts from the Zwicky Transient Facility
  4. GRB 201013A: Swift detection of a burst
  5. GRB 201008A: Swift-XRT observations
  6. Fermi trigger No 623470566: Global MASTER-Net observations report
  7. Fermi trigger No 623493962: Global MASTER-Net observations report
  8. IceCube-200926A: No candidate counterparts from the Zwicky Transient Facility
  9. IceCube-200929A: No significant detection in HAWC
  10. IceCube-200929A: No neutrino counterpart candidates in ANTARES search
  11. IceCube-200926B: No significant detection in HAWC
  12. IceCube-200926A: No Candidate Counterparts from the Zwicky Transient Facility
  13. IceCube Alert 200926.33: Global MASTER-Net observations report
  14. Fermi GRB 200925A: Global MASTER-Net observations report
  15. Fermi GRB 200924A: Global MASTER-Net observations report
  16. Fermi GRB 200923A: Global MASTER-Net observations report
  17. IceCube Alert 200921.80: Global MASTER-Net observations report
  18. GRB 200922A: Swift/UVOT Detection
  19. IceCube-200921A: no significant detection in HAWC observations
  20. Fermi GRB 200922B: Global MASTER-Net observations report
  21. GRB 200922A: LCO observations
  22. GRB 200920A: Fermi GBM Final Real-time Localization
  23. Fermi GRB 200919C: Global MASTER-Net observations report
  24. Fermi GRB 200919B: Global MASTER-Net observations report
  25. IceCube-200916A: Two Candidate Counterparts from the Zwicky Transient Facility
  26. IPN triangulation of GRB 200916B (short)
  27. IceCube Alert 200914.00: Global MASTER-Net observations report
  28. IPN triangulation of GRB 200907A (short)
  29. Fermi GRB 200908A: Global MASTER-Net observations report
  30. Fermi GRB 200907C: Global MASTER-Net observations report
  31. GRB 200906A: Nanshan/NEXT optical upper limit
  32. Fermi GRB 200903B: Global MASTER-Net observations report
  33. GRB 200901A: Fermi GBM observation
  34. GRB 200901A: Swift detection of a burst
  35. GRB 200829A: Koshka Zeiss-1000 optical observations
  36. Fermi trigger No 620402299: Global MASTER-Net observations report
  37. Zwicky Transient Facility discovery of ZTF20abtxwfx/AT2020sev, a fast optical transient and candidate afterglow
  38. IPN triangulation of GRB 200826B
  39. GRB200826A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 620108997)
  40. IPN triangulation of GRB 200815A (short)
  41. GRB 200819A: Kitab, TSHAO optical upper limit
  42. Fermi GRB 200817A: Global MASTER-Net observations report
  43. GRB 200817A: Fermi GBM Final Real-time Localization
  44. Fermi trigger No 619270776: Global MASTER-Net observations report
  45. Fermi GRB 200803A: Global MASTER-Net observations report
  46. Fermi GRB 200802A: Global MASTER-Net observations report
  47. GRB 200802A: Fermi GBM Final Real-time Localization
  48. Fermi GRB 200801A: Global MASTER-Net observations report
  49. Swift Detection of an SGR-like flare from AX J1846.4-0258
  50. Swift GRB200801.84: Global MASTER-Net observations report
  51. Fermi GRB 200716A: Global MASTER-Net observations report
  52. GRB 200716C: Swift detection of a burst with an optical counterpart
  53. Fermi GRB 200714D: Global MASTER-Net observations report
  54. Fermi GRB 200714A: Global MASTER-Net observations report
  55. Fermi trigger No 616370565: Global MASTER-Net observations report
  56. Update of alert from the HAWC Burst Monitor HAWC-200709A
  57. Fermi GRB 200705A: Global MASTER-Net observations report
  58. Trigger 980513: Swift detection of SGR Swift J1818.0-1607
  59. GRB 200630A: Swift detection of a burst
  60. Fermi GRB 200626A: Global MASTER-Net observations report
  61. IceCube-200620A: One Candidate Counterpart from the Zwicky Transient Facility
  62. LIGO/Virgo MS200618aq: Retraction of a test binary neutron star candidate
  63. Fermi trigger No 614103490: Global MASTER-Net observations report
  64. Baksan Neutrino Observatory Alert 200617.47: Global MASTER-Net observations report
  65. GRB 200616B: Fermi GBM Final Real-time Localization
  66. GRB 200615B: MAXI/GSC detection
  67. Baksan Neutrino Observatory Alert 200614.34: Global MASTER-Net observations report
  68. GRB 200614A: Fermi GBM Final Real-time Localization
  69. Swift GRB200612.19: Global MASTER-Net OT detection
  70. Swift GRB200612.19: Global MASTER-Net observations report
  71. Fermi GRB 200604A: Global MASTER-Net observations report
  72. Baksan Neutrino Observatory Alert 200603.12: Global MASTER-Net observations report
  73. GRB 200529A: MITSuME Akeno optical upper limits
  74. Fermi GRB 200601A: Global MASTER-Net observations report
  75. IceCube-200530A: Candidate Counterparts from the Zwicky Transient Facility
  76. Swift GRB 200528A: Global MASTER-Net observations report
  77. GRB 200524A: CrAO optical observations
  78. GRB 171205A: ATCA observations of late-time radio emission
  79. Fermi GRB 200522B: Global MASTER-Net observations report
  80. GRB 200522B: Fermi GBM Final Real-time Localization
  81. Fermi trigger No 611676654: Global MASTER-Net observations report
  82. GRB 200519A: Swift detection of a burst with an optical afterglow
  83. Fermi trigger No 611434353: Global MASTER-Net observations report
  84. GRB 200517A: MAXI/GSC detection
  85. GRB 200514B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 611140062) - More Candidates
  86. GRB 200514A: MITSuME Akeno optical upper limits
  87. GRB200514B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 611140062)
  88. IceCube-200512A: No Candidate Counterparts from the Zwicky Transient Facility
  89. Konus-Wind observation of SGR 1935+2154 activity on 2020 May 10
  90. GRB 200509A: Swift detection of a burst with a possible optical counterpart
  91. Insight-HXMT X-ray and hard X-ray upper limits to the radio burst detected by FAST from SGR 1935+2154
  92. Fermi GBM trigger 200429866/609886052 is not a GRB
  93. Konus-Wind observation of hard X-ray counterpart of the radio burst from SGR 1935+2154
  94. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  95. IceCube-200425A: No significant detection in HAWC
  96. GRB 200423A: Fermi GBM Final Real-time Localization
  97. Fermi GRB 200421A: Global MASTER-Net observations report
  98. GRB 200421A: Fermi GBM Final Real-time Localization
  99. Fermi trigger No 608935505: Global MASTER-Net observations report
  100. GRB 200415A: MASTER imspection and possible localisation

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