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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"

11529 results found.

  1. GRB 250206A: Fermi GBM Final Real-time Localization
  2. GRB 250205A: Fermi GBM Observation
  3. GRB 250204B: SVOM/GRM observation of a likely short burst
  4. Konus-Wind detection of GRB 250201A
  5. IPN triangulation of GRB 250201A
  6. Konus-Wind detection of GRB 250202B
  7. EP 250108A: Upper limits from Fermi-GBM Observations
  8. IPN triangulation of GRB 250204B (short/hard)
  9. IPN triangulation of GRB 250202B
  10. GRB 250204B: AstroSat CZTI detection of a short burst
  11. GRB 250204B: Fermi GBM Final Localization
  12. GRB 250204A: Fermi GBM Final Real-time Localization
  13. GRB 250202B: NuSTAR detection of the prompt emission
  14. GRB 250202C: GRBAlpha detection
  15. GRB 250202B: Fermi GBM Detection
  16. IceCube-250203A - IceCube observation of a high-energy neutrino candidate track-like event
  17. GRB 250202C: Fermi GBM Final Real-time Localization
  18. GRB 250202B: AstroSat CZTI detection of a bright long GRB
  19. GRB 250202B: Fermi GBM Final Real-time Localization
  20. GRB 250202A: Fermi GBM Final Real-time Localization
  21. GRB 250201A: INTEGRAL SPI/ACS detection
  22. GRB 250201A: BALROG localization (Fermi Trigger 760096791 / GRB 250201417)
  23. GRB 250201A: Fermi GBM Final Real-time Localization
  24. GRB 250128B: VLA possible radio detection
  25. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  26. GRB 250128B: VLA radio upper limit
  27. GRB 250128B: TNG optical upper limit
  28. GRB 250128B: NOT optical upper limit
  29. GRB 250128B: OHP/T193 optical upper limit
  30. Fermi GRB 250128B: Global MASTER-Net observations report
  31. GRB 250128B: Fermi GBM Observation
  32. GRB 250128B: GOTO optical upper limit
  33. GRB 250128B: Fermi GBM Final Real-time Localization
  34. GRB 250127B: DDOTI Upper Limit on the Afterglow
  35. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  36. Fermi GRB 250128A: Global MASTER-Net observations report
  37. GRB 250128A: Fermi GBM Final Real-time Localization
  38. GRB 250117A: Fermi GBM Observation
  39. Fermi GRB 250127B: Global MASTER-Net observations report
  40. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  41. GRB 250127B: Fermi GBM Final Real-time Localization
  42. IPN triangulation of GRB 250119C
  43. GRB 241223A: cubesat Avion detection
  44. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  45. EP250125A: Non-detection from Fermi-GBM Observations
  46. GRB 250126A: BALROG localization (Fermi Trigger 759560335 / GRB 250126208)
  47. GRB 250126A: Fermi GBM Final Real-time Localization
  48. GECAM-A detection of a bright burst from SGR 1E1841-045
  49. GRB 250118A: Fermi GBM Observation
  50. GRB 250119C: Fermi GBM Observation
  51. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  52. IPN triangulation of a bright burst from SGR 1E1841-045
  53. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  54. GRB 250121A: Fermi GBM Observation
  55. Konus-Wind detection of GRB 250119B
  56. IPN triangulation of GRB 250119B
  57. GRB 250122A: Fermi GBM Final Real-time Localization
  58. Improved IPN triangulation of GRB 250107C
  59. GRB 250121A: INTEGRAL/SPI-ACS detection
  60. GRB 250121A: Fermi-LAT detection
  61. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  62. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  63. GRB 250121A: Fermi GBM Final Real-time Localization
  64. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  65. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  66. GRB 250119B: Fermi GBM Observation
  67. IPN triangulation of GRB 250117A (short)
  68. GRB 250119B: INTEGRAL/SPI-ACS detection
  69. GRB 250117A: SVOM/GRM observation of a short burst
  70. GRB 250119C: Fermi GBM Final Real-time Localization
  71. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  72. GRB 250117A: GECAM observation of a short burst
  73. GRB 250119B: BALROG localization (Fermi Trigger 758968026 / GRB 250119352)
  74. GRB 250119B: Fermi GBM Final Real-time Localization
  75. GRB 250119A: Fermi GBM Final Real-time Localization
  76. GRB 250118A: Fermi GBM Final Real-time Localization
  77. Fermi Gamma-ray Burst Monitor trigger 758829338/250117747 is not a GRB
  78. Konus-Wind detection of GRB 250116A
  79. GRB 250116A: GECAM-B detection of a long burst
  80. GRB 241217A / EP241217B: radio detection with the VLA
  81. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  82. GRB 250116A: Fermi-LAT detection
  83. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  84. Fermi Gamma-ray Burst Monitor trigger 758659047/250115776 is not a GRB
  85. GRB 250107A: VZLUSAT-2 detection
  86. GRB 250109A / EP250109a: GRBAlpha detection
  87. Fermi trigger No 758442826: Global MASTER-Net observations report
  88. GRB 250109A / EP250109a: Mephisto optical upper limits
  89. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  90. GRB 250101B: Fermi GBM Observation
  91. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  92. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  93. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  94. GRB 250109A: Fermi GBM Observation
  95. GRB 250109a: GMG Optical Upper Limit
  96. IPN triangulation of GRB 250107C
  97. GRB 250109A /EP250109a: Fermi GBM Final Localization
  98. Fermi Gamma-ray Burst Monitor trigger 758061038/250108855 is not a GRB
  99. LIGO/Virgo/KAGRA S250108ha: Retraction of GW compact binary merger candidate
  100. GRB 250107A: Fermi GBM Observation

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