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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"

12383 results found.

  1. GRB 260204A: SVOM/VT confirms fading of the optical afterglow
  2. GRB 260204A : MASTER Global robotic net optical observations
  3. Fermi GBM Sub-Threshold Detection of GRB 260204A
  4. GRB 260204B: Fermi GBM Final Real-time Localization
  5. GRB 260131A/B: OHP/T193 optical observations
  6. GRB 260131A: KAIT optical observations
  7. GRB 260131A: FTW optical and NIR observations
  8. GRB 260131A/AT2026bwg: Observations by the Zwicky Transient Facility
  9. GRID detection of GRB 260131A/B
  10. GRB 260131A/B: GTC/OSIRIS+ redshift confimation
  11. GRB 260130A: Insight-HXMT/HE detection
  12. GRB 260130A: GECAM-B observation of a short burst
  13. GRB 260131A/B (AT2026bwg): J-band observations by SYSU 80cm infrared telescope
  14. GRB 260131A/B: EP/FXT X-ray afterglow detection
  15. GRB 260131A/B (AT2026bwg): COLIBRÍ further optical observations
  16. GRB 260127B: Insight-HXMT/HE detection
  17. GRB 260127B: GECAM-B observation of a short burst
  18. GRB 260127A: GECAM-B observation
  19. GRB 260131A: NOT spectroscopic redshift z = 1.434
  20. Konus-Wind detection of GRB 260128A / EP260128a
  21. GRB 260131A: Insight-HXMT/HE detection
  22. Konus-Wind detection of GRB 260131A/B
  23. GRB 260131A/B (AT2026bwg): COLIBRÍ optical observations and confirmation of fading
  24. GRB 260131A/B: GOTO candidate optical counterpart consistent with the MAXI localisation
  25. GRB 260131A/B: Fermi GBM Observation
  26. GRB 260131A: Fermi GBM Final Real-time Localization
  27. GRB 260127B: AstroSat CZTI detection
  28. GRB 260130A: Fermi GBM Detection
  29. GRB 260127B: Fermi GBM Detection
  30. Fermi GRB 260130A: Global MASTER-Net observations report
  31. GRB 260130A: Fermi GBM Final Real-time Localization
  32. Fermi GRB 260129A: Global MASTER-Net observations report
  33. IPN triangulation of GRB 260121A
  34. GRB 260129B: Fermi GBM Final Localization
  35. GRB 260129A: Fermi GBM Final Localization
  36. IPN triangulation of GRB 260127B (short)
  37. GRB 260127B: Swift-XRT observations
  38. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  39. GRB 260128A / EP260128a: Fermi-GBM Sub-Threshold Detection
  40. Fermi GRB 260127A: Global MASTER-Net observations report
  41. IceCube-260125A: No Candidate Transients from the Zwicky Transient Facility
  42. GRB 260127A: Fermi GBM Observation
  43. IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
  44. GRB 260127A: COLIBRÍ optical observations
  45. GRB 260127A: NOT optical observations
  46. GRB 260127B: Swift ToO observations
  47. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  48. GRB 260127B: GOTO candidate optical counterpart
  49. GRB 260127A: SVOM/C-GFT optical observations
  50. Fermi GRB 260127B: Global MASTER-Net observations report
  51. GRB 260127B: Fermi GBM Final Real-time Localization
  52. GRB 260127A: LCO optical afterglow discovery
  53. GRB 260127A: Fermi GBM Final Real-time Localization
  54. GRB 260125A: Swift-XRT observations
  55. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  56. GRB 260125A: NOT optical observations on GOTO26acv / AT 2026bjf
  57. Konus-Wind detection of GRB 260120B
  58. GRB 260125A: Swift ToO observations
  59. GRB 260125A: GOTO candidate optical counterpart
  60. Fermi GRB 260125B: Global MASTER-Net observations report
  61. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  62. GRB 260125B: Fermi GBM Final Real-time Localization
  63. GRB 260125A: Fermi GBM Final Real-time Localization
  64. GRB 260114A: SVOM/VT optical upper limits
  65. GRB 260120A: AstroSat CZTI detection
  66. GRB 260120B: SVOM/GRM observation
  67. GRB 260120A: GECAM-B observation
  68. GRB 260120B: AstroSat CZTI detection
  69. GRB 260114A: Insight-HXMT/HE detection
  70. GRB 260122A: Fermi GBM Final Real-time Localization
  71. IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
  72. Fermi GRB 260120C: Global MASTER-Net observations report
  73. GRB 260120B: Fermi GBM Observation
  74. GRB 260120B: COLIBRÍ optical upper limits
  75. GRB 260120B: SVOM/C-GFT optical counterpart detection
  76. GRB 260120C: Fermi GBM Final Real-time Localization
  77. GRB 260101A: 239Alferov CubeSat detection
  78. GRB 260120B: Fermi GBM Final Real-time Localization
  79. Fermi trigger No 790601190: Global MASTER-Net observations report
  80. Fermi trigger No 790570272: Global MASTER-Net observations report
  81. GRB 251202A: further radio observations with the VLA
  82. GRB 260120A: Fermi GBM Final Real-time Localization
  83. GRB 260115A: AstroSat CZTI detection
  84. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  85. GRB 260115A: GECAM-B observation
  86. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  87. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  88. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  89. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  90. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  91. Fermi GRB 260115A: Global MASTER-Net observations report
  92. GRB 260115A: Fermi GBM Final Real-time Localization
  93. GRB260114A: STEP/T80S optical limits
  94. GRB 251222A: radio detection with the VLA
  95. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  96. Konus-Wind detection of GRB 260114A
  97. GRB 260114A: 6 GHz VLA observations
  98. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  99. GRB 260114A : MITSuME Akeno optical upper limits
  100. GRB 260114A: COLIBRÍ optical upper limits

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