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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"

11522 results found.

  1. IPN triangulation of GRB 250204B (short/hard)
  2. IPN triangulation of GRB 250202B
  3. GRB 250204B: AstroSat CZTI detection of a short burst
  4. GRB 250204B: Fermi GBM Final Localization
  5. GRB 250204A: Fermi GBM Final Real-time Localization
  6. GRB 250202B: NuSTAR detection of the prompt emission
  7. GRB 250202C: GRBAlpha detection
  8. GRB 250202B: Fermi GBM Detection
  9. IceCube-250203A - IceCube observation of a high-energy neutrino candidate track-like event
  10. GRB 250202C: Fermi GBM Final Real-time Localization
  11. GRB 250202B: AstroSat CZTI detection of a bright long GRB
  12. GRB 250202B: Fermi GBM Final Real-time Localization
  13. GRB 250202A: Fermi GBM Final Real-time Localization
  14. GRB 250201A: INTEGRAL SPI/ACS detection
  15. GRB 250201A: BALROG localization (Fermi Trigger 760096791 / GRB 250201417)
  16. GRB 250201A: Fermi GBM Final Real-time Localization
  17. GRB 250128B: VLA possible radio detection
  18. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  19. GRB 250128B: VLA radio upper limit
  20. GRB 250128B: TNG optical upper limit
  21. GRB 250128B: NOT optical upper limit
  22. GRB 250128B: OHP/T193 optical upper limit
  23. Fermi GRB 250128B: Global MASTER-Net observations report
  24. GRB 250128B: Fermi GBM Observation
  25. GRB 250128B: GOTO optical upper limit
  26. GRB 250128B: Fermi GBM Final Real-time Localization
  27. GRB 250127B: DDOTI Upper Limit on the Afterglow
  28. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  29. Fermi GRB 250128A: Global MASTER-Net observations report
  30. GRB 250128A: Fermi GBM Final Real-time Localization
  31. GRB 250117A: Fermi GBM Observation
  32. Fermi GRB 250127B: Global MASTER-Net observations report
  33. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  34. GRB 250127B: Fermi GBM Final Real-time Localization
  35. IPN triangulation of GRB 250119C
  36. GRB 241223A: cubesat Avion detection
  37. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  38. EP250125A: Non-detection from Fermi-GBM Observations
  39. GRB 250126A: BALROG localization (Fermi Trigger 759560335 / GRB 250126208)
  40. GRB 250126A: Fermi GBM Final Real-time Localization
  41. GECAM-A detection of a bright burst from SGR 1E1841-045
  42. GRB 250118A: Fermi GBM Observation
  43. GRB 250119C: Fermi GBM Observation
  44. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  45. IPN triangulation of a bright burst from SGR 1E1841-045
  46. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  47. GRB 250121A: Fermi GBM Observation
  48. Konus-Wind detection of GRB 250119B
  49. IPN triangulation of GRB 250119B
  50. GRB 250122A: Fermi GBM Final Real-time Localization
  51. Improved IPN triangulation of GRB 250107C
  52. GRB 250121A: INTEGRAL/SPI-ACS detection
  53. GRB 250121A: Fermi-LAT detection
  54. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  55. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  56. GRB 250121A: Fermi GBM Final Real-time Localization
  57. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  58. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  59. GRB 250119B: Fermi GBM Observation
  60. IPN triangulation of GRB 250117A (short)
  61. GRB 250119B: INTEGRAL/SPI-ACS detection
  62. GRB 250117A: SVOM/GRM observation of a short burst
  63. GRB 250119C: Fermi GBM Final Real-time Localization
  64. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  65. GRB 250117A: GECAM observation of a short burst
  66. GRB 250119B: BALROG localization (Fermi Trigger 758968026 / GRB 250119352)
  67. GRB 250119B: Fermi GBM Final Real-time Localization
  68. GRB 250119A: Fermi GBM Final Real-time Localization
  69. GRB 250118A: Fermi GBM Final Real-time Localization
  70. Fermi Gamma-ray Burst Monitor trigger 758829338/250117747 is not a GRB
  71. Konus-Wind detection of GRB 250116A
  72. GRB 250116A: GECAM-B detection of a long burst
  73. GRB 241217A / EP241217B: radio detection with the VLA
  74. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  75. GRB 250116A: Fermi-LAT detection
  76. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  77. Fermi Gamma-ray Burst Monitor trigger 758659047/250115776 is not a GRB
  78. GRB 250107A: VZLUSAT-2 detection
  79. GRB 250109A / EP250109a: GRBAlpha detection
  80. Fermi trigger No 758442826: Global MASTER-Net observations report
  81. GRB 250109A / EP250109a: Mephisto optical upper limits
  82. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  83. GRB 250101B: Fermi GBM Observation
  84. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  85. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  86. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  87. GRB 250109A: Fermi GBM Observation
  88. GRB 250109a: GMG Optical Upper Limit
  89. IPN triangulation of GRB 250107C
  90. GRB 250109A /EP250109a: Fermi GBM Final Localization
  91. Fermi Gamma-ray Burst Monitor trigger 758061038/250108855 is not a GRB
  92. LIGO/Virgo/KAGRA S250108ha: Retraction of GW compact binary merger candidate
  93. GRB 250107A: Fermi GBM Observation
  94. GRB 241228B: Fermi-LAT detection
  95. Fermi GRB 250107B: Global MASTER-Net observations report
  96. GRB 250107A: Swift/BAT-GUANO arcminute localization of a burst
  97. GRB 250107B: Fermi GBM Final Real-time Localization
  98. GRB 250107A: Fermi GBM Final Real-time Localization
  99. Fermi trigger No 757753930: Global MASTER-Net observations report
  100. GRB 241228B: 1.3m DFOT Optical observations

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