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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"

11511 results found.

  1. GRB 260531B: Glowbug gamma-ray detection
  2. GRB 260601A: Fermi GBM Observation
  3. Fermi GRB 260601A: Global MASTER-Net observations report
  4. GRB 260601A: Fermi GBM Final Real-time Localization
  5. GRB 260531B: GECAM-B observation
  6. GRB 260531C: Fermi GBM Final Localization Correction
  7. Fermi Gamma-ray Burst Monitor trigger 801900520/260531256 is not a GRB
  8. Fermi trigger No 801900520: Global MASTER-Net observations report
  9. GRB 260531B: Fermi GBM Final Real-time Localization
  10. AT 2026nuz: COLIBRÍ optical observations
  11. IPN triangulation of GRB 260527A / EP260527a
  12. GRB 260530A: Fermi GBM Final Real-time Localization
  13. GRB 260529A: GOTO tentative optical afterglow candidate
  14. Fermi GRB 260529A: Global MASTER-Net observations report
  15. GRB 260529A: Fermi GBM Final Real-time Localization
  16. GRB 260526A: GECAM-B observation
  17. Fermi trigger No 801580882: Global MASTER-Net observations report
  18. GRB 260525A: AstroSat CZTI detection
  19. Fermi GRB 260526A: Global MASTER-Net observations report
  20. GRB 260526A: Fermi GBM Final Real-time Localization
  21. Fermi GRB 260525A: Global MASTER-Net observations report
  22. GRB 260525A: Fermi GBM Final Real-time Localization
  23. GRB 260523B: AstroSat CZTI detection
  24. GRB 260523B: GECAM-B observation
  25. Fermi GRB 260523A: Global MASTER-Net observations report
  26. GRB 260523B: Fermi GBM Final Real-time Localization
  27. GRB 260523A: Fermi GBM Final Real-time Localization
  28. GRB 260522A: Fermi GBM Observation
  29. GRB 260522B: NuSTAR detection of prompt emission
  30. GRB 260522B: Fermi GBM Final Real-time Localization
  31. GRB 260522A: GOTO optical upper limit
  32. Fermi trigger No 801135305: Global MASTER-Net observations report
  33. Fermi GRB 260522A: Global MASTER-Net observations report
  34. GRB 260522A: Fermi-LAT detection
  35. GRB 260522A: Fermi GBM Final Real-time Localization
  36. GRB 260511A: iTelescope T-75 optical detection
  37. GRB 260520B: SVOM/GRM observation
  38. GRB 260411B: TERI Gamma-ray detection
  39. GRB 260407A: TERI Gamma-ray detection
  40. GRB 260307A: TERI Gamma-ray detection
  41. GRB 251118A: TERI Gamma-ray detection
  42. GRB 251113A: TERI Gamma-ray detection
  43. GRB 260428A: TERI Gamma-ray detection
  44. GRB 260520B: Fermi GBM Final Localization
  45. GRB 260520A: Fermi GBM Final Localization
  46. GRB 260519D: Fermi GBM Final Localization Correction
  47. GRB 260519B: Fermi GBM Final Localization
  48. GRB 260519A: Fermi GBM Final Localization
  49. GRB 260421B: radio detection with the VLA
  50. GRID detection of GRB 260511A
  51. Fermi GRB 260516C: Global MASTER-Net observations report
  52. GRB 260516C: Fermi GBM Final Real-time Localization
  53. Fermi Gamma-ray Burst Monitor trigger 800627191/260516518 is not a GRB
  54. Fermi GRB 260516B: Global MASTER-Net observations report
  55. GRB 260516B: Fermi GBM Final Real-time Localization
  56. Fermi Gamma-ray Burst Monitor trigger 800592653/260516119 is not a GRB
  57. GRB 260516A: Fermi GBM Final Real-time Localization
  58. GRID detection of GRB 260507A
  59. GRB 260510C: Glowbug gamma-ray detection
  60. GRB 260511B: NOT optical observations
  61. Konus-Wind detection of GRB 260512A
  62. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  63. IPN triangulation of GRB 260512A
  64. Fermi GRB 260514A: Global MASTER-Net observations report
  65. GRB 260512A: AstroSat CZTI detection
  66. GRB 260514A: Fermi GBM Final Real-time Localization
  67. Fermi GRB 260513A: Global MASTER-Net observations report
  68. Fermi GRB 260512A: Global MASTER-Net observations report
  69. GRB 260511B: further SAO RAS optical observations
  70. GRB 260513A: Fermi GBM Final Real-time Localization
  71. Konus-Wind detection of GRB 260511B
  72. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  73. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  74. GRB 260512A: NuSTAR detection of prompt emission
  75. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  76. GRB 260512A: Fermi GBM Final Real-time Localization
  77. GRB 260511A: Glowbug gamma-ray detection
  78. Konus-Wind detection of GRB 260511A
  79. MASS-Cube (GRID 2.0) detection of GRB 260511A
  80. MASS-Cube (GRID 2.0) detection of GRB 260507A
  81. GRB 260511B: SAO RAS optical observations
  82. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  83. GRB 260511B: FRAM-ORM optical detection
  84. GRB 260511A: EP-FXT follow-up observation
  85. GRB 260511B: EP-FXT follow-up observation
  86. GRB 260511B: LCO optical counterpart detection
  87. GRB260511B: MAO/AZT-22 optical observations
  88. GRB 260511A: SVOM/VT optical observations
  89. GRB 260511B: LCO optical observations
  90. GRB 260511B: OHP/T193 spectroscopic observations
  91. GRB 260511B: GOTO optical counterpart detection
  92. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation
  93. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  94. GRB 260511B: SVOM/VT optical observations
  95. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  96. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  97. GRB 260510C: Fermi GBM Observation
  98. GRB 260511A: REM near-infrared detection
  99. GRB 260511B: GROWTH-India Telescope optical observations
  100. GRB 260511B: AstroSat CZTI detection

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