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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. GRB 230307A: soft X-ray detection with LEIA
  2. GRB 230307A: Gemini-South Confirmation of the Optical Afterglow
  3. Fermi GRB 230308A: Global MASTER-Net observations report
  4. GRB 230304A: Fermi GBM Final Real-time Localization
  5. Fermi trigger No 699294715: Global MASTER-Net observations report
  6. IceCube-230220A: Upper limits from a search for additional neutrino events in IceCube
  7. Fermi GRB 230220B: Global MASTER-Net observations report
  8. GRB 230217A: Gemini-South Optical Observation
  9. IceCube Alert 230217.87: Global MASTER-Net observations report
  10. Fermi trigger No 697678542: Global MASTER-Net observations report
  11. Fermi GRB 230209B: Global MASTER-Net observations report
  12. Fermi GRB 230207A: Global MASTER-Net observations report
  13. GRB 230205A: BOOTES-5/JGT early optical upper limit
  14. GRB 230204B: Detection by GRBAlpha
  15. GRB 230204B: MAXI/GSC detection
  16. Fermi trigger No 697098930: Global MASTER-Net observations report
  17. GRB 230201A: Fermi GBM Final Real-time Localization
  18. GRB 230130A: Fermi GBM Final Real-time Localization
  19. GRB 230128A: Fermi GBM Final Real-time Localization
  20. GRB 230116D: KGO RC-25 optical observations
  21. GRB 230116D: Sintez-Newton/CrAO optical observations
  22. GRB 230116D: Swift-XRT refined Analysis
  23. IceCube-230112A: No Candidate Counterparts from the Zwicky Transient Facility
  24. Fermi GRB 230112A: Global MASTER-Net observations report
  25. Fermi trigger No 695057654: Global MASTER-Net observations report
  26. IceCube-221223A: No Candidate Counterparts from the Zwicky Transient Facility
  27. Swift GRB221226.95: Global MASTER-Net observations report
  28. Fermi GRB 221226A: Global MASTER-Net observations report
  29. GRB 221226A: Fermi GBM Final Real-time Localization
  30. IceCube-221216A: No Candidate Counterparts from the Zwicky Transient Facility
  31. Integral GRB221218.34: Global MASTER-Net observations report
  32. GRB 221216A: AKO Upper Limit
  33. Fermi trigger No 692713692: Global MASTER-Net observations report
  34. Fermi GRB 221211A: Global MASTER-Net observations report
  35. IceCube Alert 221210.36: Global MASTER-Net observations report
  36. GRB 221206B: Swift/BAT-GUANO candidate arcminute localization
  37. GRB 221206C: Fermi GBM Final Real-time Localization
  38. GRB 221206B: Fermi GBM Final Real-time Localization
  39. Swift GRB221204.45: Global MASTER-Net observations report
  40. Konus-Wind detection of GRB 221124A
  41. Fermi Gamma-ray Burst Monitor trigger 691534074/221130867 is not a GRB
  42. IceCube Alert 221124.66: Global MASTER-Net observations report
  43. GRB 221120A: TURBO Optical Upper Limit
  44. Swift GRB221110.10: Global MASTER-Net observations report
  45. GRB 221107A: Fermi GBM Observation
  46. GRB 221028A: GRANDMA observations
  47. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  48. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  49. GRB 221027B: COATLI Upper Limits
  50. IPN triangulation of GRB 221022C (short)
  51. Konus-Wind detection of GRB 221023A
  52. GRB 221017A: Swift-XRT observations
  53. AGILE detection of short X-ray flaring activity contemporary to SGR J1935+2154 reported bursts
  54. MAXI GRB221017.24: Global MASTER-Net observations report
  55. GRB 221017A: MAXI/GSC detection
  56. GRB 221009A: ATCA radio spectrum
  57. Fermi trigger No 687345829: Global MASTER-Net observations report
  58. Fermi trigger No 687340841: Global MASTER-Net observations report
  59. Fermi trigger No 687337536: Global MASTER-Net observations report
  60. Fermi trigger No 687281393: Global MASTER-Net observations report
  61. Fermi-GBM Observations of High Bursting Activity from SGR J1935+2154
  62. INTEGRAL shows increasing activity in SGR J1935+2154
  63. Fermi GRB 220925A: Global MASTER-Net observations report
  64. GRB 220924A: Fermi GBM Final Real-time Localization
  65. IceCube-220907A: No significant detection in HAWC
  66. Fermi trigger No 684716840: Global MASTER-Net observations report
  67. Fermi GRB 220912A: Global MASTER-Net observations report
  68. IceCube-220907A: One Candidate Counterpart from the Zwicky Transient Facility
  69. Fermi GRB 220902A: Global MASTER-Net observations report
  70. Fermi trigger No 683202084: Global MASTER-Net observations report
  71. Fermi trigger No 683183601: Global MASTER-Net observations report
  72. IceCube-220822A: One Candidate Counterpart from the Zwicky Transient Facility
  73. GRB 220813A: Swift/UVOT Detection
  74. Fermi trigger No 681890304: Global MASTER-Net observations report
  75. Fermi trigger No 681633544: Global MASTER-Net observations report
  76. Swift GRB220806.76: Global MASTER-Net observations report
  77. Fermi trigger No 680782656: Global MASTER-Net observations report
  78. Fermi GRB 220728A: Global MASTER-Net observations report
  79. GRB 220726A: Fermi GBM Final Real-time Localization
  80. Fermi trigger No 679248723: Global MASTER-Net observations report
  81. Fermi GRB 220711B: Global MASTER-Net observations report
  82. GRB 220702B: AstroSat CZTI detection
  83. GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB
  84. Fermi trigger No 678058621: Global MASTER-Net observations report
  85. IceCube Alert 220627.74: Global MASTER-Net observations report
  86. IceCube-220624A: No Candidate Counterparts from the Zwicky Transient Facility
  87. Fermi GRB 220624A: Global MASTER-Net observations report
  88. IceCube Alert 220624.68: Global MASTER-Net observations report
  89. IPN triangulation of GRB 220624A
  90. GRB 220623A: BOOTES-5/JGT optical afterglow detection
  91. Fermi trigger No 677377371: Global MASTER-Net observations report
  92. Fermi GRB 220620A: Global MASTER-Net observations report
  93. GRB 220619A: AstroSat CZTI detection
  94. Fermi GRB 220617A: Global MASTER-Net observations report
  95. Fermi trigger No 676909037: Global MASTER-Net observations report
  96. MAXI GRB220607.31: Global MASTER-Net observations report
  97. MAXI GRB220607.41: Global MASTER-Net observations report
  98. Fermi trigger No 675992935: Global MASTER-Net observations report
  99. IPN triangulation of GRB 220528A (short)
  100. Fermi GRB 220530A: Global MASTER-Net observations report

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