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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. IPN triangulation of GRB 250202B
  2. GRB 250204B: AstroSat CZTI detection of a short burst
  3. GRB 250204B: Fermi GBM Final Localization
  4. GRB 250204A: Fermi GBM Final Real-time Localization
  5. GRB 250202B: NuSTAR detection of the prompt emission
  6. GRB 250202C: GRBAlpha detection
  7. GRB 250202B: Fermi GBM Detection
  8. IceCube-250203A - IceCube observation of a high-energy neutrino candidate track-like event
  9. GRB 250202C: Fermi GBM Final Real-time Localization
  10. GRB 250202B: AstroSat CZTI detection of a bright long GRB
  11. GRB 250202B: Fermi GBM Final Real-time Localization
  12. GRB 250202A: Fermi GBM Final Real-time Localization
  13. GRB 250201A: INTEGRAL SPI/ACS detection
  14. GRB 250201A: BALROG localization (Fermi Trigger 760096791 / GRB 250201417)
  15. GRB 250201A: Fermi GBM Final Real-time Localization
  16. GRB 250128B: VLA possible radio detection
  17. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  18. GRB 250128B: VLA radio upper limit
  19. GRB 250128B: TNG optical upper limit
  20. GRB 250128B: NOT optical upper limit
  21. GRB 250128B: OHP/T193 optical upper limit
  22. Fermi GRB 250128B: Global MASTER-Net observations report
  23. GRB 250128B: Fermi GBM Observation
  24. GRB 250128B: GOTO optical upper limit
  25. GRB 250128B: Fermi GBM Final Real-time Localization
  26. GRB 250127B: DDOTI Upper Limit on the Afterglow
  27. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  28. Fermi GRB 250128A: Global MASTER-Net observations report
  29. GRB 250128A: Fermi GBM Final Real-time Localization
  30. GRB 250117A: Fermi GBM Observation
  31. Fermi GRB 250127B: Global MASTER-Net observations report
  32. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  33. GRB 250127B: Fermi GBM Final Real-time Localization
  34. IPN triangulation of GRB 250119C
  35. GRB 241223A: cubesat Avion detection
  36. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  37. EP250125A: Non-detection from Fermi-GBM Observations
  38. GRB 250126A: BALROG localization (Fermi Trigger 759560335 / GRB 250126208)
  39. GRB 250126A: Fermi GBM Final Real-time Localization
  40. GECAM-A detection of a bright burst from SGR 1E1841-045
  41. GRB 250118A: Fermi GBM Observation
  42. GRB 250119C: Fermi GBM Observation
  43. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  44. IPN triangulation of a bright burst from SGR 1E1841-045
  45. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  46. GRB 250121A: Fermi GBM Observation
  47. Konus-Wind detection of GRB 250119B
  48. IPN triangulation of GRB 250119B
  49. GRB 250122A: Fermi GBM Final Real-time Localization
  50. Improved IPN triangulation of GRB 250107C
  51. GRB 250121A: INTEGRAL/SPI-ACS detection
  52. GRB 250121A: Fermi-LAT detection
  53. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  54. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  55. GRB 250121A: Fermi GBM Final Real-time Localization
  56. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  57. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  58. GRB 250119B: Fermi GBM Observation
  59. IPN triangulation of GRB 250117A (short)
  60. GRB 250119B: INTEGRAL/SPI-ACS detection
  61. GRB 250117A: SVOM/GRM observation of a short burst
  62. GRB 250119C: Fermi GBM Final Real-time Localization
  63. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  64. GRB 250117A: GECAM observation of a short burst
  65. GRB 250119B: BALROG localization (Fermi Trigger 758968026 / GRB 250119352)
  66. GRB 250119B: Fermi GBM Final Real-time Localization
  67. GRB 250119A: Fermi GBM Final Real-time Localization
  68. GRB 250118A: Fermi GBM Final Real-time Localization
  69. Fermi Gamma-ray Burst Monitor trigger 758829338/250117747 is not a GRB
  70. Konus-Wind detection of GRB 250116A
  71. GRB 250116A: GECAM-B detection of a long burst
  72. GRB 241217A / EP241217B: radio detection with the VLA
  73. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  74. GRB 250116A: Fermi-LAT detection
  75. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  76. Fermi Gamma-ray Burst Monitor trigger 758659047/250115776 is not a GRB
  77. GRB 250107A: VZLUSAT-2 detection
  78. GRB 250109A / EP250109a: GRBAlpha detection
  79. Fermi trigger No 758442826: Global MASTER-Net observations report
  80. GRB 250109A / EP250109a: Mephisto optical upper limits
  81. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  82. GRB 250101B: Fermi GBM Observation
  83. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  84. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  85. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  86. GRB 250109A: Fermi GBM Observation
  87. GRB 250109a: GMG Optical Upper Limit
  88. IPN triangulation of GRB 250107C
  89. GRB 250109A /EP250109a: Fermi GBM Final Localization
  90. Fermi Gamma-ray Burst Monitor trigger 758061038/250108855 is not a GRB
  91. LIGO/Virgo/KAGRA S250108ha: Retraction of GW compact binary merger candidate
  92. GRB 250107A: Fermi GBM Observation
  93. GRB 241228B: Fermi-LAT detection
  94. Fermi GRB 250107B: Global MASTER-Net observations report
  95. GRB 250107A: Swift/BAT-GUANO arcminute localization of a burst
  96. GRB 250107B: Fermi GBM Final Real-time Localization
  97. GRB 250107A: Fermi GBM Final Real-time Localization
  98. Fermi trigger No 757753930: Global MASTER-Net observations report
  99. GRB 241228B: 1.3m DFOT Optical observations
  100. GRB 250103A: NOT spectroscopic redshift

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