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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"

2925 results found.

  1. GRB 230427A : OHP/T193 optical upper limit
  2. GRB 230426A: Fermi GBM Detection
  3. Fermi GRB 230409C: Global MASTER-Net observations report
  4. GRB 230405B: Prompt enhanced Swift-XRT position
  5. GRB 230328B: Fermi GBM Final Real-time Localization
  6. GRB 230325A: X-shooter optical afterglow and redshift
  7. GRB 230325A: Prompt enhanced Swift-XRT position
  8. GRB 230322B: Swift/UVOT Detection
  9. Konus-Wind detection of GRB 230308A
  10. GRB 230322B: Swift detection of a burst with optical counterpart
  11. Fermi trigger No 701058254: Global MASTER-Net observations report
  12. GRB 230314A: TURBO Optical Upper Limit
  13. Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
  14. Fermi trigger No 700976129: Global MASTER-Net observations report
  15. GRB 230314A: Fermi GBM Final Real-time Localization
  16. Fermi GRB 230313A: Global MASTER-Net observations report
  17. GRB 230307A: soft X-ray detection with LEIA
  18. GRB 230307A: Gemini-South Confirmation of the Optical Afterglow
  19. Fermi GRB 230308A: Global MASTER-Net observations report
  20. GRB 230304A: Fermi GBM Final Real-time Localization
  21. Fermi trigger No 699294715: Global MASTER-Net observations report
  22. IceCube-230220A: Upper limits from a search for additional neutrino events in IceCube
  23. Fermi GRB 230220B: Global MASTER-Net observations report
  24. GRB 230217A: Gemini-South Optical Observation
  25. IceCube Alert 230217.87: Global MASTER-Net observations report
  26. Fermi trigger No 697678542: Global MASTER-Net observations report
  27. Fermi GRB 230209B: Global MASTER-Net observations report
  28. Fermi GRB 230207A: Global MASTER-Net observations report
  29. GRB 230205A: BOOTES-5/JGT early optical upper limit
  30. GRB 230204B: Detection by GRBAlpha
  31. GRB 230204B: MAXI/GSC detection
  32. Fermi trigger No 697098930: Global MASTER-Net observations report
  33. GRB 230201A: Fermi GBM Final Real-time Localization
  34. GRB 230130A: Fermi GBM Final Real-time Localization
  35. GRB 230128A: Fermi GBM Final Real-time Localization
  36. GRB 230116D: KGO RC-25 optical observations
  37. GRB 230116D: Sintez-Newton/CrAO optical observations
  38. GRB 230116D: Swift-XRT refined Analysis
  39. IceCube-230112A: No Candidate Counterparts from the Zwicky Transient Facility
  40. Fermi GRB 230112A: Global MASTER-Net observations report
  41. Fermi trigger No 695057654: Global MASTER-Net observations report
  42. IceCube-221223A: No Candidate Counterparts from the Zwicky Transient Facility
  43. Swift GRB221226.95: Global MASTER-Net observations report
  44. Fermi GRB 221226A: Global MASTER-Net observations report
  45. GRB 221226A: Fermi GBM Final Real-time Localization
  46. IceCube-221216A: No Candidate Counterparts from the Zwicky Transient Facility
  47. Integral GRB221218.34: Global MASTER-Net observations report
  48. GRB 221216A: AKO Upper Limit
  49. Fermi trigger No 692713692: Global MASTER-Net observations report
  50. Fermi GRB 221211A: Global MASTER-Net observations report
  51. IceCube Alert 221210.36: Global MASTER-Net observations report
  52. GRB 221206B: Swift/BAT-GUANO candidate arcminute localization
  53. GRB 221206C: Fermi GBM Final Real-time Localization
  54. GRB 221206B: Fermi GBM Final Real-time Localization
  55. Swift GRB221204.45: Global MASTER-Net observations report
  56. Konus-Wind detection of GRB 221124A
  57. Fermi Gamma-ray Burst Monitor trigger 691534074/221130867 is not a GRB
  58. IceCube Alert 221124.66: Global MASTER-Net observations report
  59. GRB 221120A: TURBO Optical Upper Limit
  60. Swift GRB221110.10: Global MASTER-Net observations report
  61. GRB 221107A: Fermi GBM Observation
  62. GRB 221028A: GRANDMA observations
  63. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  64. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  65. GRB 221027B: COATLI Upper Limits
  66. IPN triangulation of GRB 221022C (short)
  67. Konus-Wind detection of GRB 221023A
  68. GRB 221017A: Swift-XRT observations
  69. AGILE detection of short X-ray flaring activity contemporary to SGR J1935+2154 reported bursts
  70. MAXI GRB221017.24: Global MASTER-Net observations report
  71. GRB 221017A: MAXI/GSC detection
  72. GRB 221009A: ATCA radio spectrum
  73. Fermi trigger No 687345829: Global MASTER-Net observations report
  74. Fermi trigger No 687340841: Global MASTER-Net observations report
  75. Fermi trigger No 687337536: Global MASTER-Net observations report
  76. Fermi trigger No 687281393: Global MASTER-Net observations report
  77. Fermi-GBM Observations of High Bursting Activity from SGR J1935+2154
  78. INTEGRAL shows increasing activity in SGR J1935+2154
  79. Fermi GRB 220925A: Global MASTER-Net observations report
  80. GRB 220924A: Fermi GBM Final Real-time Localization
  81. IceCube-220907A: No significant detection in HAWC
  82. Fermi trigger No 684716840: Global MASTER-Net observations report
  83. Fermi GRB 220912A: Global MASTER-Net observations report
  84. IceCube-220907A: One Candidate Counterpart from the Zwicky Transient Facility
  85. Fermi GRB 220902A: Global MASTER-Net observations report
  86. Fermi trigger No 683202084: Global MASTER-Net observations report
  87. Fermi trigger No 683183601: Global MASTER-Net observations report
  88. IceCube-220822A: One Candidate Counterpart from the Zwicky Transient Facility
  89. Fermi trigger No 681890304: Global MASTER-Net observations report
  90. Fermi trigger No 681633544: Global MASTER-Net observations report
  91. Swift GRB220806.76: Global MASTER-Net observations report
  92. Fermi trigger No 680782656: Global MASTER-Net observations report
  93. Fermi GRB 220728A: Global MASTER-Net observations report
  94. GRB 220726A: Fermi GBM Final Real-time Localization
  95. Fermi trigger No 679248723: Global MASTER-Net observations report
  96. Fermi GRB 220711B: Global MASTER-Net observations report
  97. GRB 220702B: AstroSat CZTI detection
  98. GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB
  99. Fermi trigger No 678058621: Global MASTER-Net observations report
  100. IceCube Alert 220627.74: Global MASTER-Net observations report

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