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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"

3028 results found.

  1. GRB 230430A: AstroSat CZTI detection
  2. GRB 230430A: Fermi GBM Final Real-time Localization
  3. Fermi trigger No 704365743: Global MASTER-Net observations report
  4. GRB 230427A : OHP/T193 optical upper limit
  5. GRB 230426A: Fermi GBM Detection
  6. Fermi GRB 230409C: Global MASTER-Net observations report
  7. GRB 230405B: Prompt enhanced Swift-XRT position
  8. GRB 230328B: Fermi GBM Final Real-time Localization
  9. GRB 230325A: X-shooter optical afterglow and redshift
  10. GRB 230325A: Prompt enhanced Swift-XRT position
  11. GRB 230322B: Swift/UVOT Detection
  12. Konus-Wind detection of GRB 230308A
  13. GRB 230322B: Swift detection of a burst with optical counterpart
  14. Fermi trigger No 701058254: Global MASTER-Net observations report
  15. GRB 230314A: TURBO Optical Upper Limit
  16. Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
  17. Fermi trigger No 700976129: Global MASTER-Net observations report
  18. GRB 230314A: Fermi GBM Final Real-time Localization
  19. Fermi GRB 230313A: Global MASTER-Net observations report
  20. GRB 230307A: soft X-ray detection with LEIA
  21. GRB 230307A: Gemini-South Confirmation of the Optical Afterglow
  22. Fermi GRB 230308A: Global MASTER-Net observations report
  23. GRB 230304A: Fermi GBM Final Real-time Localization
  24. Fermi trigger No 699294715: Global MASTER-Net observations report
  25. IceCube-230220A: Upper limits from a search for additional neutrino events in IceCube
  26. Fermi GRB 230220B: Global MASTER-Net observations report
  27. GRB 230217A: Gemini-South Optical Observation
  28. IceCube Alert 230217.87: Global MASTER-Net observations report
  29. Fermi trigger No 697678542: Global MASTER-Net observations report
  30. Fermi GRB 230209B: Global MASTER-Net observations report
  31. Fermi GRB 230207A: Global MASTER-Net observations report
  32. GRB 230205A: BOOTES-5/JGT early optical upper limit
  33. GRB 230204B: Detection by GRBAlpha
  34. GRB 230204B: MAXI/GSC detection
  35. Fermi trigger No 697098930: Global MASTER-Net observations report
  36. GRB 230201A: Fermi GBM Final Real-time Localization
  37. GRB 230130A: Fermi GBM Final Real-time Localization
  38. GRB 230128A: Fermi GBM Final Real-time Localization
  39. GRB 230116D: KGO RC-25 optical observations
  40. GRB 230116D: Sintez-Newton/CrAO optical observations
  41. GRB 230116D: Swift-XRT refined Analysis
  42. IceCube-230112A: No Candidate Counterparts from the Zwicky Transient Facility
  43. Fermi GRB 230112A: Global MASTER-Net observations report
  44. Fermi trigger No 695057654: Global MASTER-Net observations report
  45. IceCube-221223A: No Candidate Counterparts from the Zwicky Transient Facility
  46. Swift GRB221226.95: Global MASTER-Net observations report
  47. Fermi GRB 221226A: Global MASTER-Net observations report
  48. GRB 221226A: Fermi GBM Final Real-time Localization
  49. IceCube-221216A: No Candidate Counterparts from the Zwicky Transient Facility
  50. Integral GRB221218.34: Global MASTER-Net observations report
  51. GRB 221216A: AKO Upper Limit
  52. Fermi trigger No 692713692: Global MASTER-Net observations report
  53. Fermi GRB 221211A: Global MASTER-Net observations report
  54. IceCube Alert 221210.36: Global MASTER-Net observations report
  55. GRB 221206B: Swift/BAT-GUANO candidate arcminute localization
  56. GRB 221206C: Fermi GBM Final Real-time Localization
  57. GRB 221206B: Fermi GBM Final Real-time Localization
  58. Swift GRB221204.45: Global MASTER-Net observations report
  59. Konus-Wind detection of GRB 221124A
  60. Fermi Gamma-ray Burst Monitor trigger 691534074/221130867 is not a GRB
  61. IceCube Alert 221124.66: Global MASTER-Net observations report
  62. GRB 221120A: TURBO Optical Upper Limit
  63. Swift GRB221110.10: Global MASTER-Net observations report
  64. GRB 221107A: Fermi GBM Observation
  65. GRB 221028A: GRANDMA observations
  66. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  67. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  68. GRB 221027B: COATLI Upper Limits
  69. IPN triangulation of GRB 221022C (short)
  70. Konus-Wind detection of GRB 221023A
  71. GRB 221017A: Swift-XRT observations
  72. AGILE detection of short X-ray flaring activity contemporary to SGR J1935+2154 reported bursts
  73. MAXI GRB221017.24: Global MASTER-Net observations report
  74. GRB 221017A: MAXI/GSC detection
  75. GRB 221009A: ATCA radio spectrum
  76. Fermi trigger No 687345829: Global MASTER-Net observations report
  77. Fermi trigger No 687340841: Global MASTER-Net observations report
  78. Fermi trigger No 687337536: Global MASTER-Net observations report
  79. Fermi trigger No 687281393: Global MASTER-Net observations report
  80. Fermi-GBM Observations of High Bursting Activity from SGR J1935+2154
  81. INTEGRAL shows increasing activity in SGR J1935+2154
  82. Fermi GRB 220925A: Global MASTER-Net observations report
  83. GRB 220924A: Fermi GBM Final Real-time Localization
  84. IceCube-220907A: No significant detection in HAWC
  85. Fermi trigger No 684716840: Global MASTER-Net observations report
  86. Fermi GRB 220912A: Global MASTER-Net observations report
  87. IceCube-220907A: One Candidate Counterpart from the Zwicky Transient Facility
  88. Fermi GRB 220902A: Global MASTER-Net observations report
  89. Fermi trigger No 683202084: Global MASTER-Net observations report
  90. Fermi trigger No 683183601: Global MASTER-Net observations report
  91. IceCube-220822A: One Candidate Counterpart from the Zwicky Transient Facility
  92. Fermi trigger No 681890304: Global MASTER-Net observations report
  93. Fermi trigger No 681633544: Global MASTER-Net observations report
  94. Swift GRB220806.76: Global MASTER-Net observations report
  95. Fermi trigger No 680782656: Global MASTER-Net observations report
  96. Fermi GRB 220728A: Global MASTER-Net observations report
  97. GRB 220726A: Fermi GBM Final Real-time Localization
  98. Fermi trigger No 679248723: Global MASTER-Net observations report
  99. Fermi GRB 220711B: Global MASTER-Net observations report
  100. GRB 220702B: AstroSat CZTI detection

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