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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"

42935 results found.

  1. IPN triangulation of GRB 260207B (short/hard with EE)
  2. GRB 260210C: Fermi GBM Final Real-time Localization
  3. GRB 260210A: Glowbug gamma-ray detection
  4. GRB 260210B: Fermi GBM Final Real-time Localization
  5. EP260210a: SVOM/VT optical upper limit
  6. GRB 260210A: AstroSat CZTI detection
  7. GRB 260208C: AstroSat CZTI detection
  8. EP260210a: COLIBRÍ optical upper limit
  9. EP260210a: SVOM/C-GFT upper limit
  10. GRB 260208B: refined analysis of the EP-FXT observation
  11. EP260210a: Einstein Probe detection of an X-ray transient
  12. GRB 260207B: AstroSat CZTI detection
  13. GRB 260208C: SVOM/GRM observation
  14. GRB 260204A: Swift-XRT afterglow detection
  15. GRB 260208B: AstroSat CZTI detection of a bright long burst
  16. GRB260208A: Liverpool Telescope optical follow-up observations
  17. GRB 260208A: Glowbug gamma-ray detection
  18. GRB 260208A: NuSTAR detection of prompt emission
  19. GRB 260208A: Fermi GBM Observation
  20. Fermi GRB 260209A: Global MASTER-Net observations report
  21. GRB 260208B: Swift-XRT observations
  22. GRB 260131A/B: continued Mondy optical observations
  23. GRB 260204A: Swift/UVOT Upper Limits
  24. GRB 260208B: COLIBRÍ optical observations
  25. GRB 260208A: Mondy optical observations
  26. GRB 260208A: 1.3m DFOT optical detection
  27. GRB 260208A: COLIBRÍ optical observations
  28. GRB 260208B: EP-FXT observation
  29. GRB 260208A: NOT spectroscopic redshift z = 2.36
  30. GRB 260208A: Liverpool Telescope optical detection
  31. Fermi GRB 260208C: Global MASTER-Net observations report
  32. GRB 260208B: SVOM/VT optical candidate
  33. GRB 260208A: GECAM-B observation of a bright burst
  34. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)
  35. GRB 260209A: Fermi GBM Final Real-time Localization
  36. GRB 260208A: SVOM/VT optical observation
  37. Fermi GRB 260208D: Global MASTER-Net observations report
  38. GRB 260208D: Fermi GBM Final Real-time Localization
  39. GRB 260208A: Swift-XRT observations
  40. GRB 260208B: Swift ToO observations
  41. GRB 260208B: SVOM/GRM observation of a bright burst
  42. GRB 260208B: Fermi GBM Detection
  43. LAT GRB 260208B: Global MASTER-Net observations report
  44. GRB 260208B: Fermi-LAT detection
  45. GRB 260208C: Fermi GBM Final Real-time Localization
  46. GRB 260208A: Fermi-LAT detection
  47. GRB 260207B: GECAM-B observation
  48. GRB 260208A: Swift ToO observations
  49. GRB 260208A: Fermi GBM Classification Correction
  50. GRB 260208A: GOTO detection of a potential optical counterpart (GOTO26aob)
  51. GRB 260208A : MASTER bright optical transient inside retracted Fermi error-box
  52. GRB 260208B: BALROG localization (Fermi Trigger 792237169 / GRB 260208412)
  53. GRB 260208B: Fermi GBM Final Real-time Localization
  54. Fermi GRB 260208A: Global MASTER-Net observations report
  55. GRB 260208A: Fermi GBM Final Real-time Localization
  56. GRB 260207B: Fermi GBM Detection of a Short Burst with Extended Emission
  57. GRB 260207A : MASTER optical counterpart discovery
  58. GRB 260131A/B: Mondy and Terskol optical observations
  59. Fermi GRB 260207B: Global MASTER-Net observations report
  60. GRB 260206A: Swift-XRT observations
  61. GRB 260207B: Fermi GBM Final Real-time Localization
  62. GRB 260207A: Fermi GBM Final Localization
  63. Fermi trigger No 792135758: Global MASTER-Net observations report
  64. EP260131a: VLA detection
  65. GRB 260206A: Tiled Swift observations
  66. GRB 260206A (or XRB from 4U 0513-40): MAXI/GSC detection
  67. GRB 260204A: SVOM/VT confirms fading of the optical afterglow
  68. GRB 260204A: Swift-XRT observations
  69. GRB 260204A: LCO optical afterglow detection
  70. GRB 260204A: SVOM/VT optical candidate
  71. GRB 260204A : MASTER Global robotic net optical observations
  72. Fermi GBM Sub-Threshold Detection of GRB 260204A
  73. GRB 260204A: GOTO optical upper limit
  74. GRB 260204A: LCO optical upper limits
  75. EP260110a: Late GTC/EMIR near-infrared observations
  76. GRB 260204B: Fermi GBM Final Real-time Localization
  77. GRB 260204A: SVOM detection of a burst
  78. GRB 260121A: 239Alferov CubeSat detection
  79. Konus-Wind detection of GRB 260121A
  80. GRB 260131A/B: OHP/T193 optical observations
  81. GRB 260131A: KAIT optical observations
  82. GRB 251230A: MeerLICHT afterglow detection
  83. GRB 260131A: FTW optical and NIR observations
  84. GRB 260131A/AT2026bwg: Observations by the Zwicky Transient Facility
  85. GRID detection of GRB 260131A/B
  86. GRB 260131A/B: GTC/OSIRIS+ redshift confimation
  87. GRB 260130A: Insight-HXMT/HE detection
  88. GRB 260130A: GECAM-B observation of a short burst
  89. GRB 260131A/B (AT2026bwg): J-band observations by SYSU 80cm infrared telescope
  90. GRB 260131A/B: EP/FXT X-ray afterglow detection
  91. GRB 260131A/B (AT2026bwg): COLIBRÍ further optical observations
  92. GRB 260127B: Insight-HXMT/HE detection
  93. GRB 260127B: GECAM-B observation of a short burst
  94. GRB 260127A: GECAM-B observation
  95. GRB 260131A: NOT spectroscopic redshift z = 1.434
  96. EP260131a: Liverpool Telescope optical upper limits
  97. EP260131a: COLIBRÍ further observations
  98. Konus-Wind detection of GRB 260128A / EP260128a
  99. GRB 260131A: Insight-HXMT/HE detection
  100. Konus-Wind detection of GRB 260131A/B

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