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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"

29093 results found.

  1. Fermi GRB 260130A: Global MASTER-Net observations report
  2. EP260128a / GRB 260128A: NOT and TNG optical and NIR upper limits
  3. GRB 260130A: Fermi GBM Final Real-time Localization
  4. Fermi GRB 260129A: Global MASTER-Net observations report
  5. GRB 260128B: LCO optical upper limits
  6. GRB 260128B: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  7. EP260128a: J band upper limit by SYSU 80cm infrared telescope
  8. IPN triangulation of GRB 260121A
  9. GRB 260127A: Swift-BAT refined analysis
  10. GRB 260129B: Fermi GBM Final Localization
  11. GRB 260128B: SVOM detection of a burst through offline search
  12. GRB 260129A: Fermi GBM Final Localization
  13. IPN triangulation of GRB 260127B (short)
  14. GRB 260127B: Swift-XRT observations
  15. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  16. GRB 260128A / EP260128a: Fermi-GBM Sub-Threshold Detection
  17. EP260128a: NOT optical counterpart candidate
  18. EP260128a: LCO optical upper limits
  19. EP260126a: SVOM/VT optical upperlimit
  20. EP260128a: Global MASTER-Net observations report
  21. Fermi GRB 260127A: Global MASTER-Net observations report
  22. GRB 260127A: Fermi GBM Observation
  23. GRB 260127A: COLIBRÍ optical observations
  24. GRB 260127A: NOT optical observations
  25. GRB 260127B: Swift ToO observations
  26. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  27. GRB 260127A: Swift-XRT refined Analysis
  28. GRB 260127B: GOTO candidate optical counterpart
  29. GRB 260127A: SVOM/C-GFT optical observations
  30. The EP-WXT trigger 01709253145 is likely a flaring star
  31. Fermi GRB 260127B: Global MASTER-Net observations report
  32. GRB 260127B: Fermi GBM Final Real-time Localization
  33. Swift GRB 260127A: Global MASTER-Net observations report
  34. GRB 260127A: LCO optical afterglow discovery
  35. GRB 260127A: Swift detection of a burst
  36. GRB 260127A: Fermi GBM Final Real-time Localization
  37. GRB 260125A: Swift-XRT observations
  38. EP260126a: Optical upper limit with Kinder observations
  39. EP260126a: Further NOT optical upper limits
  40. EP260126a: COLIBRÍ optical upper limits
  41. EP260126a: NOT optical observations
  42. EP260126a: Einstein Probe detection of a fast X-ray transient
  43. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  44. GRB 260125A: NOT optical observations on GOTO26acv / AT 2026bjf
  45. Konus-Wind detection of GRB 260120B
  46. GRB 260125A: Swift ToO observations
  47. GRB 260125A: GOTO candidate optical counterpart
  48. Fermi GRB 260125B: Global MASTER-Net observations report
  49. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  50. GRB 260125B: Fermi GBM Final Real-time Localization
  51. GRB 260125A: Fermi GBM Final Real-time Localization
  52. GRB 260114A: SVOM/VT optical upper limits
  53. GRB 260120A: AstroSat CZTI detection
  54. GRB 260122B: Swift-BAT refined analysis
  55. GRB 260120B: SVOM/GRM observation
  56. GRB 260120A: GECAM-B observation
  57. GRB 260120B: AstroSat CZTI detection
  58. GRB 260114A: Insight-HXMT/HE detection
  59. GRB 260122B: Swift detection of a burst
  60. Swift GRB260122.97: Global MASTER-Net observations report
  61. GRB 260122A: Fermi GBM Final Real-time Localization
  62. EP260119a: Xinglong optical upper limit
  63. The EP-WXT trigger 01709251871 is likely a flaring star
  64. Fermi GRB 260120C: Global MASTER-Net observations report
  65. GRB 260120B: Swift-BAT refined analysis
  66. GRB 260120B: Swift-XRT refined Analysis
  67. EP260116a: COLIBRÍ further observations
  68. GRB 260120B: Fermi GBM Observation
  69. EP260105a: GTC/HiPERCAM optical observations
  70. GRB 260120B: Swift/UVOT Detection
  71. GRB 260120B: COLIBRÍ optical upper limits
  72. SVOM GRB260121.06: Global MASTER-Net observations report
  73. GRB 260120B: SVOM/C-GFT optical counterpart detection
  74. GRB 260120C: Fermi GBM Final Real-time Localization
  75. GRB 260101A: 239Alferov CubeSat detection
  76. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  77. GRB 260120B: Swift detection of a burst
  78. Swift GRB260120B: Global MASTER-Net observations report
  79. GRB 260120B: Fermi GBM Final Real-time Localization
  80. Fermi trigger No 790601190: Global MASTER-Net observations report
  81. Fermi trigger No 790570272: Global MASTER-Net observations report
  82. GRB 260114A: Swift/UVOT Upper Limits
  83. EP260119a: Liverpool Telescope optical follow-up observations
  84. GRB 251202A: further radio observations with the VLA
  85. Trigger 1442421: Swift detection of HMXB 1A 1118-61
  86. EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
  87. GRB 260120A: Fermi GBM Final Real-time Localization
  88. EP260119a: SVOM/VT optical observation
  89. EP260119a: NOT optical observations
  90. SVOM GRB260119.92: Global MASTER-Net observations report
  91. SVOM GRB260119.92: Global MASTER-Net observations report
  92. SVOM GRB260119.90: Global MASTER-Net observations report
  93. EP260116a: COLIBRÍ detection of a fading optical source
  94. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  95. EP260119a: Global MASTER-Net observations report
  96. GRB 260115A: AstroSat CZTI detection
  97. EP260119a: LCO optical observations
  98. EP260119a: COLIBRÍ optical counterpart candidate
  99. GRB 260110A: SVOM detection of a burst through offline search
  100. EP260119a: EP-WXT detection of a fast X-ray transient

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