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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"

12376 results found.

  1. GRB 260131A/AT2026bwg: Observations by the Zwicky Transient Facility
  2. GRID detection of GRB 260131A/B
  3. GRB 260131A/B: GTC/OSIRIS+ redshift confimation
  4. GRB 260130A: Insight-HXMT/HE detection
  5. GRB 260130A: GECAM-B observation of a short burst
  6. GRB 260131A/B (AT2026bwg): J-band observations by SYSU 80cm infrared telescope
  7. GRB 260131A/B: EP/FXT X-ray afterglow detection
  8. GRB 260131A/B (AT2026bwg): COLIBRÍ further optical observations
  9. GRB 260127B: Insight-HXMT/HE detection
  10. GRB 260127B: GECAM-B observation of a short burst
  11. GRB 260127A: GECAM-B observation
  12. GRB 260131A: NOT spectroscopic redshift z = 1.434
  13. Konus-Wind detection of GRB 260128A / EP260128a
  14. GRB 260131A: Insight-HXMT/HE detection
  15. Konus-Wind detection of GRB 260131A/B
  16. GRB 260131A/B (AT2026bwg): COLIBRÍ optical observations and confirmation of fading
  17. GRB 260131A/B: GOTO candidate optical counterpart consistent with the MAXI localisation
  18. GRB 260131A/B: Fermi GBM Observation
  19. GRB 260131A: Fermi GBM Final Real-time Localization
  20. GRB 260127B: AstroSat CZTI detection
  21. GRB 260130A: Fermi GBM Detection
  22. GRB 260127B: Fermi GBM Detection
  23. Fermi GRB 260130A: Global MASTER-Net observations report
  24. GRB 260130A: Fermi GBM Final Real-time Localization
  25. Fermi GRB 260129A: Global MASTER-Net observations report
  26. IPN triangulation of GRB 260121A
  27. GRB 260129B: Fermi GBM Final Localization
  28. GRB 260129A: Fermi GBM Final Localization
  29. IPN triangulation of GRB 260127B (short)
  30. GRB 260127B: Swift-XRT observations
  31. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  32. GRB 260128A / EP260128a: Fermi-GBM Sub-Threshold Detection
  33. Fermi GRB 260127A: Global MASTER-Net observations report
  34. IceCube-260125A: No Candidate Transients from the Zwicky Transient Facility
  35. GRB 260127A: Fermi GBM Observation
  36. IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
  37. GRB 260127A: COLIBRÍ optical observations
  38. GRB 260127A: NOT optical observations
  39. GRB 260127B: Swift ToO observations
  40. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  41. GRB 260127B: GOTO candidate optical counterpart
  42. GRB 260127A: SVOM/C-GFT optical observations
  43. Fermi GRB 260127B: Global MASTER-Net observations report
  44. GRB 260127B: Fermi GBM Final Real-time Localization
  45. GRB 260127A: LCO optical afterglow discovery
  46. GRB 260127A: Fermi GBM Final Real-time Localization
  47. GRB 260125A: Swift-XRT observations
  48. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  49. GRB 260125A: NOT optical observations on GOTO26acv / AT 2026bjf
  50. Konus-Wind detection of GRB 260120B
  51. GRB 260125A: Swift ToO observations
  52. GRB 260125A: GOTO candidate optical counterpart
  53. Fermi GRB 260125B: Global MASTER-Net observations report
  54. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  55. GRB 260125B: Fermi GBM Final Real-time Localization
  56. GRB 260125A: Fermi GBM Final Real-time Localization
  57. GRB 260114A: SVOM/VT optical upper limits
  58. GRB 260120A: AstroSat CZTI detection
  59. GRB 260120B: SVOM/GRM observation
  60. GRB 260120A: GECAM-B observation
  61. GRB 260120B: AstroSat CZTI detection
  62. GRB 260114A: Insight-HXMT/HE detection
  63. GRB 260122A: Fermi GBM Final Real-time Localization
  64. IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
  65. Fermi GRB 260120C: Global MASTER-Net observations report
  66. GRB 260120B: Fermi GBM Observation
  67. GRB 260120B: COLIBRÍ optical upper limits
  68. GRB 260120B: SVOM/C-GFT optical counterpart detection
  69. GRB 260120C: Fermi GBM Final Real-time Localization
  70. GRB 260101A: 239Alferov CubeSat detection
  71. GRB 260120B: Fermi GBM Final Real-time Localization
  72. Fermi trigger No 790601190: Global MASTER-Net observations report
  73. Fermi trigger No 790570272: Global MASTER-Net observations report
  74. GRB 251202A: further radio observations with the VLA
  75. GRB 260120A: Fermi GBM Final Real-time Localization
  76. GRB 260115A: AstroSat CZTI detection
  77. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  78. GRB 260115A: GECAM-B observation
  79. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  80. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  81. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  82. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  83. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  84. Fermi GRB 260115A: Global MASTER-Net observations report
  85. GRB 260115A: Fermi GBM Final Real-time Localization
  86. GRB260114A: STEP/T80S optical limits
  87. GRB 251222A: radio detection with the VLA
  88. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  89. Konus-Wind detection of GRB 260114A
  90. GRB 260114A: 6 GHz VLA observations
  91. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  92. GRB 260114A : MITSuME Akeno optical upper limits
  93. GRB 260114A: COLIBRÍ optical upper limits
  94. GRB 260114A: TNG NIR upper limit
  95. GRB 260114A: NOT optical observations
  96. GRB 260114A: SVOM/GRM observation of a short burst
  97. GRB 260114A: GECAM-B observation of a short burst
  98. GRB 260114A: Mondy optical observations
  99. GRB 260114A: Fermi GBM observation
  100. GRB 260112B: GECAM-B observation

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