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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"

11099 results found.

  1. GRB 250223A: Fermi GBM Final Real-time Localization
  2. Fermi trigger No 761805304: Global MASTER-Net observations report
  3. Fermi Gamma-ray Burst Monitor trigger 761867337/250221909 is not a GRB
  4. Fermi Gamma-ray Burst Monitor trigger 761788229/250220993 is not a GRB
  5. GRB 250220B: Fermi GBM Final Real-time Localization
  6. Fermi Gamma-ray Burst Monitor trigger 761782146/250220923 is not a GRB
  7. GRB 250220A: Fermi GBM Final Real-time Localization
  8. Konus-Wind detection of GRB 250217C (short)
  9. Konus-Wind detection of GRB 250215A / EP250215a
  10. GRB 250217C: COLIBRÍ/DDRAGO Upper Limits on the Optical Counterpart
  11. GRB 250217C: DDOTI Upper Limits on the Optical Afterglow
  12. GRB 250217C: SVOM/GRM observation
  13. GRB 250217C: Fermi GBM Observation
  14. GRB 250215A / EP250215A: Encouraging Follow-up Observations of a BdHN I with a Rest-Frame Duration 2.3 s at z=4.61
  15. IPN triangulation of GRB 250217C (short)
  16. GRB 250216A: AstroSat CZTI detection
  17. GRB 250217C: AstroSat CZTI detection of a short burst
  18. Fermi GRB 250217C: Global MASTER-Net observations report
  19. GRB 250217C: Fermi GBM Final Real-time Localization
  20. Fermi GRB 250217A: Global MASTER-Net observations report
  21. GRANDMA/OPD observations of GRB250215A
  22. GRB 250217B: Fermi GBM Final Real-time Localization
  23. GRB 250217A: Fermi GBM Final Real-time Localization
  24. Fermi GRB 250216A: Global MASTER-Net observations report
  25. GRB 250215A / EP250215a: LCO detection of the afterglow
  26. GRB 250216A: Fermi GBM Final Real-time Localization
  27. GRB 250215A: Swift/UVOT Upper Limits
  28. GRB 250215A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  29. EP250215a / GRB 250215A : GTC redshift z = 4.61
  30. GRB 250215A: Fermi GBM Observation
  31. EP250215a / GRB 250215A : NOT optical observations
  32. GRB 250215A/EP250215a: 1.6m Mephisto optical observation report
  33. GRB 250215A / EP250215a: Gemini-South optical observation of a likely rebrightening
  34. GRB 250215A: Swift-XRT refined Analysis
  35. GRB 250215A: SVOM/GRM observation
  36. EP250215a / GRB 250215A: AstroSat CZTI detection
  37. GRB 250215A / EP250215a: SVOM/VT optical candidate comfirmation
  38. EP250215A/GRB 250215A: INTEGRAL SPI-ACS detection
  39. EP250215a / GRB 250215A (potentially): NOT likely optical counterpart
  40. Fermi GRB 250215A: Global MASTER-Net observations report
  41. GRB 250215A: Fermi GBM Final Real-time Localization
  42. Fermi trigger No 761206993: Global MASTER-Net observations report
  43. Fermi Gamma-ray Burst Monitor trigger 761206993/250214266 is not a GRB
  44. Fermi GRB 250214A: Global MASTER-Net observations report
  45. GRB 250214A: Fermi GBM Final Real-time Localization
  46. GRB 250210A: GRBAlpha detection
  47. Fermi GRB 250212A: Global MASTER-Net observations report
  48. Fermi trigger No 760945500: Global MASTER-Net observations report
  49. GRB 250212A: Fermi GBM Final Real-time Localization
  50. GRB 250207A: Fermi GBM Observation
  51. GRB 250206A: Fermi GBM Observation
  52. GRB 250205A / EP250205A: radio detection with the VLA
  53. Konus-Wind detection of GRB 250207A
  54. Konus-Wind detection of GRB 250206A
  55. GRB 250210A: SVOM/GRM observation of a long burst
  56. Fermi Gamma-ray Burst Monitor trigger 760945500/250211240 is not a GRB
  57. GRB 250207A: Skynet optical afterglow observations
  58. EP250207A: Upper limits from Fermi-GBM Observations
  59. GRB 250210A: INTEGRAL SPI-ACS detection
  60. GRB 250210A: AstroSat CZTI detection
  61. Fermi GRB 250210A: Global MASTER-Net observations report
  62. GRB 250210A: Fermi GBM Final Real-time Localization
  63. GRB 250204B: GRBAlpha detection
  64. GRB 250204A: GRBAlpha detection
  65. Fermi-LAT Gamma-ray Observations of IceCube-250207A
  66. GRB 250206A: Swift-XRT observations
  67. GRB 250206A: Tiled Swift observations
  68. GRB 250206A: EIRSAT-1 GMOD Detection
  69. GRB 250206A: Fermi-LAT detection
  70. GRB 250208A: Fermi GBM Final Real-time Localization
  71. GRB 250207A: REM IR afterglow detection
  72. GRB 250207A: FRAM-Auger optical detection
  73. Konus-Wind detection of GRB 250204B
  74. IceCube-250207A - IceCube observation of a high-energy neutrino candidate track-like event
  75. GRB 250207A: REM optical afterglow detection
  76. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  77. LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
  78. GRB 250207A: Fermi GBM Final Real-time Localization
  79. Fermi-LAT Gamma-ray Observations of IceCube-250203A
  80. GRB 250206A: BALROG localization (Fermi Trigger 760564296 / GRB 250206827)
  81. GRB 250206A: Fermi GBM Final Real-time Localization
  82. GRB 250205A: Fermi GBM Observation
  83. GRB 250204B: SVOM/GRM observation of a likely short burst
  84. Konus-Wind detection of GRB 250201A
  85. IPN triangulation of GRB 250201A
  86. Konus-Wind detection of GRB 250202B
  87. EP 250108A: Upper limits from Fermi-GBM Observations
  88. IPN triangulation of GRB 250204B (short/hard)
  89. IPN triangulation of GRB 250202B
  90. GRB 250204B: AstroSat CZTI detection of a short burst
  91. GRB 250204B: Fermi GBM Final Localization
  92. GRB 250204A: Fermi GBM Final Real-time Localization
  93. GRB 250202B: NuSTAR detection of the prompt emission
  94. GRB 250202C: GRBAlpha detection
  95. GRB 250202B: Fermi GBM Detection
  96. IceCube-250203A - IceCube observation of a high-energy neutrino candidate track-like event
  97. GRB 250202C: Fermi GBM Final Real-time Localization
  98. GRB 250202B: AstroSat CZTI detection of a bright long GRB
  99. GRB 250202B: Fermi GBM Final Real-time Localization
  100. GRB 250202A: Fermi GBM Final Real-time Localization

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