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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"

11514 results found.

  1. Konus-Wind detection of GRB 250202B
  2. EP 250108A: Upper limits from Fermi-GBM Observations
  3. IPN triangulation of GRB 250204B (short/hard)
  4. IPN triangulation of GRB 250202B
  5. GRB 250204B: AstroSat CZTI detection of a short burst
  6. GRB 250204B: Fermi GBM Final Localization
  7. GRB 250204A: Fermi GBM Final Real-time Localization
  8. GRB 250202B: NuSTAR detection of the prompt emission
  9. GRB 250202C: GRBAlpha detection
  10. GRB 250202B: Fermi GBM Detection
  11. IceCube-250203A - IceCube observation of a high-energy neutrino candidate track-like event
  12. GRB 250202C: Fermi GBM Final Real-time Localization
  13. GRB 250202B: AstroSat CZTI detection of a bright long GRB
  14. GRB 250202B: Fermi GBM Final Real-time Localization
  15. GRB 250202A: Fermi GBM Final Real-time Localization
  16. GRB 250201A: INTEGRAL SPI/ACS detection
  17. GRB 250201A: BALROG localization (Fermi Trigger 760096791 / GRB 250201417)
  18. GRB 250201A: Fermi GBM Final Real-time Localization
  19. GRB 250128B: VLA possible radio detection
  20. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  21. GRB 250128B: VLA radio upper limit
  22. GRB 250128B: TNG optical upper limit
  23. GRB 250128B: NOT optical upper limit
  24. GRB 250128B: OHP/T193 optical upper limit
  25. Fermi GRB 250128B: Global MASTER-Net observations report
  26. GRB 250128B: Fermi GBM Observation
  27. GRB 250128B: GOTO optical upper limit
  28. GRB 250128B: Fermi GBM Final Real-time Localization
  29. GRB 250127B: DDOTI Upper Limit on the Afterglow
  30. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  31. Fermi GRB 250128A: Global MASTER-Net observations report
  32. GRB 250128A: Fermi GBM Final Real-time Localization
  33. GRB 250117A: Fermi GBM Observation
  34. Fermi GRB 250127B: Global MASTER-Net observations report
  35. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  36. GRB 250127B: Fermi GBM Final Real-time Localization
  37. IPN triangulation of GRB 250119C
  38. GRB 241223A: cubesat Avion detection
  39. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  40. EP250125A: Non-detection from Fermi-GBM Observations
  41. GRB 250126A: BALROG localization (Fermi Trigger 759560335 / GRB 250126208)
  42. GRB 250126A: Fermi GBM Final Real-time Localization
  43. GECAM-A detection of a bright burst from SGR 1E1841-045
  44. GRB 250118A: Fermi GBM Observation
  45. GRB 250119C: Fermi GBM Observation
  46. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  47. IPN triangulation of a bright burst from SGR 1E1841-045
  48. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  49. GRB 250121A: Fermi GBM Observation
  50. Konus-Wind detection of GRB 250119B
  51. IPN triangulation of GRB 250119B
  52. GRB 250122A: Fermi GBM Final Real-time Localization
  53. Improved IPN triangulation of GRB 250107C
  54. GRB 250121A: INTEGRAL/SPI-ACS detection
  55. GRB 250121A: Fermi-LAT detection
  56. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  57. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  58. GRB 250121A: Fermi GBM Final Real-time Localization
  59. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  60. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  61. GRB 250119B: Fermi GBM Observation
  62. IPN triangulation of GRB 250117A (short)
  63. GRB 250119B: INTEGRAL/SPI-ACS detection
  64. GRB 250117A: SVOM/GRM observation of a short burst
  65. GRB 250119C: Fermi GBM Final Real-time Localization
  66. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  67. GRB 250117A: GECAM observation of a short burst
  68. GRB 250119B: BALROG localization (Fermi Trigger 758968026 / GRB 250119352)
  69. GRB 250119B: Fermi GBM Final Real-time Localization
  70. GRB 250119A: Fermi GBM Final Real-time Localization
  71. GRB 250118A: Fermi GBM Final Real-time Localization
  72. Fermi Gamma-ray Burst Monitor trigger 758829338/250117747 is not a GRB
  73. Konus-Wind detection of GRB 250116A
  74. GRB 250116A: GECAM-B detection of a long burst
  75. GRB 241217A / EP241217B: radio detection with the VLA
  76. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  77. GRB 250116A: Fermi-LAT detection
  78. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  79. Fermi Gamma-ray Burst Monitor trigger 758659047/250115776 is not a GRB
  80. GRB 250107A: VZLUSAT-2 detection
  81. GRB 250109A / EP250109a: GRBAlpha detection
  82. Fermi trigger No 758442826: Global MASTER-Net observations report
  83. GRB 250109A / EP250109a: Mephisto optical upper limits
  84. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  85. GRB 250101B: Fermi GBM Observation
  86. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  87. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  88. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  89. GRB 250109A: Fermi GBM Observation
  90. GRB 250109a: GMG Optical Upper Limit
  91. IPN triangulation of GRB 250107C
  92. GRB 250109A /EP250109a: Fermi GBM Final Localization
  93. Fermi Gamma-ray Burst Monitor trigger 758061038/250108855 is not a GRB
  94. LIGO/Virgo/KAGRA S250108ha: Retraction of GW compact binary merger candidate
  95. GRB 250107A: Fermi GBM Observation
  96. GRB 241228B: Fermi-LAT detection
  97. Fermi GRB 250107B: Global MASTER-Net observations report
  98. GRB 250107A: Swift/BAT-GUANO arcminute localization of a burst
  99. GRB 250107B: Fermi GBM Final Real-time Localization
  100. GRB 250107A: Fermi GBM Final Real-time Localization

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