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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"

3116 results found.

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

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