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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"

11519 results found.

  1. GRB 260601A: SVOM/GRM observation of a short burst
  2. Fermi GRB 260602B: Global MASTER-Net observations report
  3. Fermi GRB 260602B: Global MASTER-Net observations report
  4. GRB 260602B: Fermi GBM Final Localization
  5. GRB 260601A: GECAM-B observation of a short burst
  6. GRB 260602A: Fermi GBM Final Real-time Localization
  7. GRB 260601B / EP260601a: NuSTAR detection of prompt emission
  8. GRB 260601A: Glowbug gamma-ray detection of a short burst
  9. GRB 260531B: Glowbug gamma-ray detection
  10. GRB 260601A: Fermi GBM Observation
  11. Fermi GRB 260601A: Global MASTER-Net observations report
  12. GRB 260601A: Fermi GBM Final Real-time Localization
  13. GRB 260531B: GECAM-B observation
  14. GRB 260531C: Fermi GBM Final Localization Correction
  15. Fermi Gamma-ray Burst Monitor trigger 801900520/260531256 is not a GRB
  16. Fermi trigger No 801900520: Global MASTER-Net observations report
  17. GRB 260531B: Fermi GBM Final Real-time Localization
  18. AT 2026nuz: COLIBRÍ optical observations
  19. IPN triangulation of GRB 260527A / EP260527a
  20. GRB 260530A: Fermi GBM Final Real-time Localization
  21. GRB 260529A: GOTO tentative optical afterglow candidate
  22. Fermi GRB 260529A: Global MASTER-Net observations report
  23. GRB 260529A: Fermi GBM Final Real-time Localization
  24. GRB 260526A: GECAM-B observation
  25. Fermi trigger No 801580882: Global MASTER-Net observations report
  26. GRB 260525A: AstroSat CZTI detection
  27. Fermi GRB 260526A: Global MASTER-Net observations report
  28. GRB 260526A: Fermi GBM Final Real-time Localization
  29. Fermi GRB 260525A: Global MASTER-Net observations report
  30. GRB 260525A: Fermi GBM Final Real-time Localization
  31. GRB 260523B: AstroSat CZTI detection
  32. GRB 260523B: GECAM-B observation
  33. Fermi GRB 260523A: Global MASTER-Net observations report
  34. GRB 260523B: Fermi GBM Final Real-time Localization
  35. GRB 260523A: Fermi GBM Final Real-time Localization
  36. GRB 260522A: Fermi GBM Observation
  37. GRB 260522B: NuSTAR detection of prompt emission
  38. GRB 260522B: Fermi GBM Final Real-time Localization
  39. GRB 260522A: GOTO optical upper limit
  40. Fermi trigger No 801135305: Global MASTER-Net observations report
  41. Fermi GRB 260522A: Global MASTER-Net observations report
  42. GRB 260522A: Fermi-LAT detection
  43. GRB 260522A: Fermi GBM Final Real-time Localization
  44. GRB 260511A: iTelescope T-75 optical detection
  45. GRB 260520B: SVOM/GRM observation
  46. GRB 260411B: TERI Gamma-ray detection
  47. GRB 260407A: TERI Gamma-ray detection
  48. GRB 260307A: TERI Gamma-ray detection
  49. GRB 251118A: TERI Gamma-ray detection
  50. GRB 251113A: TERI Gamma-ray detection
  51. GRB 260428A: TERI Gamma-ray detection
  52. GRB 260520B: Fermi GBM Final Localization
  53. GRB 260520A: Fermi GBM Final Localization
  54. GRB 260519D: Fermi GBM Final Localization Correction
  55. GRB 260519B: Fermi GBM Final Localization
  56. GRB 260519A: Fermi GBM Final Localization
  57. GRB 260421B: radio detection with the VLA
  58. GRID detection of GRB 260511A
  59. Fermi GRB 260516C: Global MASTER-Net observations report
  60. GRB 260516C: Fermi GBM Final Real-time Localization
  61. Fermi Gamma-ray Burst Monitor trigger 800627191/260516518 is not a GRB
  62. Fermi GRB 260516B: Global MASTER-Net observations report
  63. GRB 260516B: Fermi GBM Final Real-time Localization
  64. Fermi Gamma-ray Burst Monitor trigger 800592653/260516119 is not a GRB
  65. GRB 260516A: Fermi GBM Final Real-time Localization
  66. GRID detection of GRB 260507A
  67. GRB 260510C: Glowbug gamma-ray detection
  68. GRB 260511B: NOT optical observations
  69. Konus-Wind detection of GRB 260512A
  70. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  71. IPN triangulation of GRB 260512A
  72. Fermi GRB 260514A: Global MASTER-Net observations report
  73. GRB 260512A: AstroSat CZTI detection
  74. GRB 260514A: Fermi GBM Final Real-time Localization
  75. Fermi GRB 260513A: Global MASTER-Net observations report
  76. Fermi GRB 260512A: Global MASTER-Net observations report
  77. GRB 260511B: further SAO RAS optical observations
  78. GRB 260513A: Fermi GBM Final Real-time Localization
  79. Konus-Wind detection of GRB 260511B
  80. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  81. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  82. GRB 260512A: NuSTAR detection of prompt emission
  83. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  84. GRB 260512A: Fermi GBM Final Real-time Localization
  85. GRB 260511A: Glowbug gamma-ray detection
  86. Konus-Wind detection of GRB 260511A
  87. MASS-Cube (GRID 2.0) detection of GRB 260511A
  88. MASS-Cube (GRID 2.0) detection of GRB 260507A
  89. GRB 260511B: SAO RAS optical observations
  90. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  91. GRB 260511B: FRAM-ORM optical detection
  92. GRB 260511A: EP-FXT follow-up observation
  93. GRB 260511B: EP-FXT follow-up observation
  94. GRB 260511B: LCO optical counterpart detection
  95. GRB260511B: MAO/AZT-22 optical observations
  96. GRB 260511A: SVOM/VT optical observations
  97. GRB 260511B: LCO optical observations
  98. GRB 260511B: OHP/T193 spectroscopic observations
  99. GRB 260511B: GOTO optical counterpart detection
  100. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation

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