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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"

11527 results found.

  1. GRB 260604C: SVOM detection of a long burst
  2. GRB 260604C: Fermi GBM Final Real-time Localization
  3. GRB 260604B: Fermi GBM Final Real-time Localization
  4. GRB 260601A: CALET Gamma-Ray Burst Monitor detection
  5. GRB 260604A: Fermi GBM Final Real-time Localization
  6. GRB 260603B: Fermi GBM Final Localization
  7. Konus-Wind detection of GRB 260601B/EP260601a
  8. Fermi trigger No 802141998: Global MASTER-Net observations report
  9. GRB 260601A: SVOM/GRM observation of a short burst
  10. Fermi GRB 260602B: Global MASTER-Net observations report
  11. Fermi GRB 260602B: Global MASTER-Net observations report
  12. GRB 260602B: Fermi GBM Final Localization
  13. GRB 260601A: GECAM-B observation of a short burst
  14. GRB 260602A: Fermi GBM Final Real-time Localization
  15. GRB 260601B / EP260601a: NuSTAR detection of prompt emission
  16. GRB 260601A: Glowbug gamma-ray detection of a short burst
  17. GRB 260531B: Glowbug gamma-ray detection
  18. GRB 260601A: Fermi GBM Observation
  19. Fermi GRB 260601A: Global MASTER-Net observations report
  20. GRB 260601A: Fermi GBM Final Real-time Localization
  21. GRB 260531B: GECAM-B observation
  22. GRB 260531C: Fermi GBM Final Localization Correction
  23. Fermi Gamma-ray Burst Monitor trigger 801900520/260531256 is not a GRB
  24. Fermi trigger No 801900520: Global MASTER-Net observations report
  25. GRB 260531B: Fermi GBM Final Real-time Localization
  26. AT 2026nuz: COLIBRÍ optical observations
  27. IPN triangulation of GRB 260527A / EP260527a
  28. GRB 260530A: Fermi GBM Final Real-time Localization
  29. GRB 260529A: GOTO tentative optical afterglow candidate
  30. Fermi GRB 260529A: Global MASTER-Net observations report
  31. GRB 260529A: Fermi GBM Final Real-time Localization
  32. GRB 260526A: GECAM-B observation
  33. Fermi trigger No 801580882: Global MASTER-Net observations report
  34. GRB 260525A: AstroSat CZTI detection
  35. Fermi GRB 260526A: Global MASTER-Net observations report
  36. GRB 260526A: Fermi GBM Final Real-time Localization
  37. Fermi GRB 260525A: Global MASTER-Net observations report
  38. GRB 260525A: Fermi GBM Final Real-time Localization
  39. GRB 260523B: AstroSat CZTI detection
  40. GRB 260523B: GECAM-B observation
  41. Fermi GRB 260523A: Global MASTER-Net observations report
  42. GRB 260523B: Fermi GBM Final Real-time Localization
  43. GRB 260523A: Fermi GBM Final Real-time Localization
  44. GRB 260522A: Fermi GBM Observation
  45. GRB 260522B: NuSTAR detection of prompt emission
  46. GRB 260522B: Fermi GBM Final Real-time Localization
  47. GRB 260522A: GOTO optical upper limit
  48. Fermi trigger No 801135305: Global MASTER-Net observations report
  49. Fermi GRB 260522A: Global MASTER-Net observations report
  50. GRB 260522A: Fermi-LAT detection
  51. GRB 260522A: Fermi GBM Final Real-time Localization
  52. GRB 260511A: iTelescope T-75 optical detection
  53. GRB 260520B: SVOM/GRM observation
  54. GRB 260411B: TERI Gamma-ray detection
  55. GRB 260407A: TERI Gamma-ray detection
  56. GRB 260307A: TERI Gamma-ray detection
  57. GRB 251118A: TERI Gamma-ray detection
  58. GRB 251113A: TERI Gamma-ray detection
  59. GRB 260428A: TERI Gamma-ray detection
  60. GRB 260520B: Fermi GBM Final Localization
  61. GRB 260520A: Fermi GBM Final Localization
  62. GRB 260519D: Fermi GBM Final Localization Correction
  63. GRB 260519B: Fermi GBM Final Localization
  64. GRB 260519A: Fermi GBM Final Localization
  65. GRB 260421B: radio detection with the VLA
  66. GRID detection of GRB 260511A
  67. Fermi GRB 260516C: Global MASTER-Net observations report
  68. GRB 260516C: Fermi GBM Final Real-time Localization
  69. Fermi Gamma-ray Burst Monitor trigger 800627191/260516518 is not a GRB
  70. Fermi GRB 260516B: Global MASTER-Net observations report
  71. GRB 260516B: Fermi GBM Final Real-time Localization
  72. Fermi Gamma-ray Burst Monitor trigger 800592653/260516119 is not a GRB
  73. GRB 260516A: Fermi GBM Final Real-time Localization
  74. GRID detection of GRB 260507A
  75. GRB 260510C: Glowbug gamma-ray detection
  76. GRB 260511B: NOT optical observations
  77. Konus-Wind detection of GRB 260512A
  78. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  79. IPN triangulation of GRB 260512A
  80. Fermi GRB 260514A: Global MASTER-Net observations report
  81. GRB 260512A: AstroSat CZTI detection
  82. GRB 260514A: Fermi GBM Final Real-time Localization
  83. Fermi GRB 260513A: Global MASTER-Net observations report
  84. Fermi GRB 260512A: Global MASTER-Net observations report
  85. GRB 260511B: further SAO RAS optical observations
  86. GRB 260513A: Fermi GBM Final Real-time Localization
  87. Konus-Wind detection of GRB 260511B
  88. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  89. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  90. GRB 260512A: NuSTAR detection of prompt emission
  91. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  92. GRB 260512A: Fermi GBM Final Real-time Localization
  93. GRB 260511A: Glowbug gamma-ray detection
  94. Konus-Wind detection of GRB 260511A
  95. MASS-Cube (GRID 2.0) detection of GRB 260511A
  96. MASS-Cube (GRID 2.0) detection of GRB 260507A
  97. GRB 260511B: SAO RAS optical observations
  98. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  99. GRB 260511B: FRAM-ORM optical detection
  100. GRB 260511A: EP-FXT follow-up observation

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