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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"
  1. GRB 231205B : MITSuME Akeno optical upper limits
  2. GRB 231206A: GECAM-B detection of a short burst
  3. GRB 231205B: Zadko observatory - Gingin optical observations
  4. GRB 231205B: Gaoyazi/GOT optical upper limit
  5. GRB 231205B: Nanshan/HMT optical upper limit
  6. GRB 231205B: GECAM-B detection of a long burst
  7. GRB 231205B: LCOGT Optical Upper Limits
  8. GRB 231205A: DDOTI Upper Limits on the Afterglow
  9. LIGO/Virgo/KAGRA S231205c: One counterpart neutrino candidate event from an IceCube neutrino search
  10. GRB 231205B: Enhanced Swift-XRT position
  11. GRB 231204A: Glowbug gamma-ray detection
  12. Swift GRB231205.70: Global MASTER-Net observations report
  13. GRB 231204A: CALET Gamma-Ray Burst Monitor detection
  14. Fermi-LAT daily aperture light curve of T CrB now available
  15. GRB 231205B: AKO Optical Upper Limit
  16. GRB 231205B: Swift detection of a burst
  17. GRB 231205A: joint location of multiple instruments by ETJASMIN
  18. GRB 231204A: AstroSat CZTI detection
  19. GRB 231205A: GECAM-B detection of a short burst
  20. Fermi trigger No 723435916: Global MASTER-Net observations report
  21. Fermi trigger No 723326169: Global MASTER-Net observations report
  22. GRB 231205A: Fermi GBM Final Real-time Localization
  23. LIGO/Virgo/KAGRA S231129ac: Upper limits from Swift/BAT-GUANO
  24. IceCube-231202A: Upper limits from a search for additional neutrino events in IceCube
  25. Fermi trigger No 723412808: Global MASTER-Net observations report
  26. GRB 231203A: Fermi GBM Observation
  27. GRB 231204A: Fermi GBM Final Real-time Localization
  28. GRB 231203A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  29. Konus-Wind detection of GRB 231129C
  30. IceCube-231202A - IceCube observation of a high-energy neutrino candidate track-like event
  31. Fermi trigger No 723279695: Global MASTER-Net observations report
  32. The Fermi GBM team reports the detection of a likely SHORT GRB
  33. GRB 231203A: Fermi GBM Final Real-time Localization
  34. GRB 231129C: Swift-XRT afterglow detection
  35. Fermi trigger No 723149952: Global MASTER-Net observations report
  36. GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
  37. GRB 231129A: VZLUSAT-2 detection
  38. GRB 231129B: Swift-XRT observations
  39. GRB 231128A: VZLUSAT-2 detection
  40. Optical transient in the field of Messier 31, likely a new blazar: back to bright state
  41. GRB 231129C: AGILE detection
  42. GRB 231129A : MITSuME Akeno optical upper limits
  43. GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
  44. GRB 231129A: Swift-BAT refined analysis
  45. GRB 231129C: MASTER OT detection
  46. GRB 231129A: BOOTES-5/JGT optical upper limit
  47. GRB 231129C: Fermi-LAT detection
  48. GRB 231129A: JinShan optical upper limit
  49. GRB 231129C: GRBAlpha detection
  50. GRB 231129C: Glowbug gamma-ray detection
  51. GRB 231129C: Swift-XRT observations
  52. GRB 231129A: Swift/UVOT Upper Limits
  53. GRB 231129A: optical upper limit in Mondy observatory
  54. GRB 231129C: GECAM-B detection of a bright burst
  55. GRB 231129C: AstroSat CZTI detection
  56. GRB 231129C: iTelescope OT retraction
  57. GRB 231129C: CALET Gamma-Ray Burst Monitor detection
  58. GRB 231129C: Fermi GBM Observation of a very bright GRB
  59. GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
  60. GRB 231129C: Tiled Swift observations
  61. GRB 231127A: GRBAlpha detection
  62. GRB 231129C: MAXI/GSC detection
  63. GRB 231129C: BALROG localization (Fermi Trigger / GRB 231129799)
  64. GRB 231129C: Fermi GBM detection of a very bright burst
  65. GRB 231129A: Enhanced Swift-XRT position
  66. LIGO/Virgo/KAGRA S231129ac: Updated Sky localization
  67. GRB 231129A: Swift-XRT refined Analysis
  68. GRB 231129C: Fermi GBM Final Real-time Localization
  69. Fermi trigger No 722977823: Global MASTER-Net observations report
  70. GRB 231129B: Tiled Swift observations
  71. GRB 231129B: MAXI/GSC detection
  72. Fermi-LAT gamma-ray observations of IceCube-231125A
  73. Integral GRB231129.21: Global MASTER-Net observations report
  74. LIGO/Virgo/KAGRA S231129ac: Identification of a GW compact binary merger candidate
  75. GRB 231129A: GECAM-C detection of a long burst
  76. GRB 231129A: INTEGRAL detection of a long GRB
  77. GRB 231129A: Swift detection of a burst
  78. LIGO/Virgo/KAGRA S231127cg: Updated Sky localization
  79. GRB 231128A: Fermi GBM Final Real-time Localization
  80. GRB 231123C: Fermi GBM Observation
  81. GRB 231123B: Fermi GBM Observation
  82. IceCube-231125A: Upper limits from a search for additional neutrino events in IceCube
  83. LIGO/Virgo/KAGRA S231127cg: Identification of a GW compact binary merger candidate
  84. GRB 231117A: MeerKAT 1.3GHz detection
  85. GRB 231127A: CALET Gamma-Ray Burst Monitor detection
  86. GRB 231125A: GRBAlpha detection
  87. GRB 231125A: CALET Gamma-Ray Burst Monitor detection
  88. GRB 231127A: AstroSat CZTI detection
  89. GRB 231125A (short): Glowbug gamma-ray detection
  90. GRB 231123B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  91. Update of IceCube-231125A - Corrected errors
  92. GRB 231124A: GRBAlpha detection
  93. IceCube-231125A - IceCube observation of a high-energy neutrino candidate track-like event
  94. Fermi trigger No 722653947: Global MASTER-Net observations report
  95. GRB 231125A: AstroSat CZTI detection of a short burst
  96. GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
  97. GRB 231126A: Fermi GBM Final Real-time Localization
  98. GRB 231123C: Insight-HXMT/HE detection
  99. Fermi trigger No 722460326: Global MASTER-Net observations report
  100. Fermi trigger No 722507896: Global MASTER-Net observations report

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