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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"

21525 results found.

  1. GRB 210226A: GIT optical upper limit
  2. GRB 210306A: HCT optical upper limit
  3. Konus-Wind detection of GRB 210308A
  4. Konus-Wind detection of GRB 210306A
  5. Konus-Wind detection of GRB 210305A
  6. GRB 210306A: Early Spectroscopy of the Optical Afterglow
  7. GRB 210306B: Fermi GBM detection
  8. GRB 210306A: Swift/UVOT Detection
  9. GRB 210308A: Swift-BAT refined analysis
  10. GRB 210307A: Swift-BAT refined analysis
  11. GRB 210308A: Swift/UVOT Detection
  12. GRB 210307A: Swift/UVOT Upper Limits
  13. GRB 210305A: Fermi GBM observation
  14. Swift GRB 210308A: Global MASTER-Net observations report
  15. GRB 210308A: Fermi GBM detection
  16. GRB 210305A: Swift-XRT refined Analysis
  17. GRB 210307A: Swift-XRT refined Analysis
  18. GRB 210306A: Swift-XRT refined Analysis
  19. GRB 210308A: MITSuME Okayama optical upper limits
  20. GRB 210308A: Swift detection of a burst with an optical counterpart
  21. GRB 210306A: Swift-BAT refined analysis
  22. GRB 210305A: Swift/UVOT Upper Limits
  23. GRB 210307A: LCO Optical Upper Limits
  24. GRB 210306B: Swift-BAT refined analysis
  25. GRB 210305A: Swift-BAT refined analysis
  26. GRB 210307A: Swift detection of a burst
  27. Swift GRB210307.36: Global MASTER-Net observations report
  28. GRB 210306A: MITSuME Akeno optical observation
  29. Swift GRB 210306A: Global MASTER-Net observations report
  30. GRB 210306A: Fermi GBM observation
  31. GRB 210306A: Fermi-LAT detection
  32. GRB 210306B: Swift detection of a burst
  33. GRB 210306A: LCO Optical Afterglow Detection
  34. GRB 210306A: DDOTI Afterglow Confirmation
  35. GRB 210306A: Swift detection of a burst with a bright optical counterpart
  36. Swift GRB 210305A: Global MASTER-Net observations report
  37. GRB 210305A: Swift detection of a burst
  38. Trigger 1035744: Swift detection of Sco X-1 due to Star Tracker loss of lock
  39. GRB 210226A: Swift/UVOT Upper Limits
  40. GRB 210226A: Swift-BAT refined analysis
  41. GRB 210226A: Fermi GBM detection
  42. GRB 210217A: Mondy optical observations
  43. GRB 210226A: KAIT Optical Upper Limit
  44. GRB 210226A: Swift-XRT refined Analysis
  45. Swift GRB 210226A: Global MASTER-Net observations report
  46. GRB 210218A: Swift-XRT confirmation of afterglow
  47. GRB 210226A: Enhanced Swift-XRT position
  48. GRB 210226A: Ondrejov BART/SBT optical limit
  49. GRB 210222B: 1.3m DFOT Optical upper limit
  50. GRB 210226A: Swift detection of a burst
  51. GRB 210222B: MITSuME Akeno optical upper limits
  52. GRB 210222B: Swift-BAT refined analysis
  53. GRB 210222B: Swift-XRT refined Analysis
  54. GRB 210222B: Swift/UVOT Detection
  55. GRB 210222B: KAIT Optical Upper Limit
  56. GRB 210218A: Swift/UVOT observations
  57. GRB 210217A: Swift/UVOT Detection
  58. GRB 210222B: MASTER OT observation
  59. GRB 210222B: GOTO confirmation of afterglow detection
  60. GRB210222B: LCO Optical Afterglow Detection
  61. GRB210222B: BOOTES-1 optical afterglow detection
  62. GRB 210222B: Swift detection of a burst with an optical counterpart
  63. Swift GRB210222.94: Global MASTER-Net observations report
  64. GRB 210218A: Swift-XRT observations
  65. GRB 210212A: Lowell Discovery Telescope observations
  66. GRB 210217A: 1.3m DFOT optical detection
  67. GRB 210217A: Swift-XRT refined Analysis
  68. GRB 210218A: Swift-BAT refined analysis
  69. Fermi GBM Sub-Threshold Detection of GRB 210217A
  70. GRB 210217A: Liverpool Telescope First Hour Observations
  71. GRB 210217A: Swift-BAT refined analysis
  72. GRB 210217A: KAIT Optical Observations
  73. GRB 210218A: MITSuME Akeno optical upper limits
  74. GRB 210218A： GWAC-F60A optical upper limit
  75. GRB 210218A: NEXT optical upper limit
  76. GRB 210218A: Swift detection of a burst
  77. GRB 210212A: REM early-time optical/NIR upper limits
  78. GRB 210205A: observations with the 3.6m DOT, a potential dark burst?
  79. GRB 210217A: Enhanced Swift-XRT position
  80. Fermi/GBM observation of a burst from SGR 1830-0645
  81. GRB 210217A: NEXT early optical afterglow observations
  82. GRB 210212A: Mondy optical observations
  83. GRB 210217A: Swift detection of a burst with an optical counterpart
  84. GRB 210210A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
  85. Swift Trigger 1033144: Detection of SGR 1830-0645
  86. GRB 210212B: Swift ToO observations
  87. IPN triangulation of GRB 210212B (consistent with ZTF21aakruew/AT2021cwd)
  88. GRB 210212A: 1.3m DFOT Optical upper limit
  89. GRB 210212A: Gemini South optical observations
  90. Swift Trigger 1032350: Detection of SGR 1830-0645
  91. GRB 210212A: Possible host galaxy counterpart with the NOT
  92. Swift GRB 210212A: Global MASTER-Net observations report
  93. GRB 210212A: MITSuME Akeno optical upper limits
  94. GRB 210212A: Swift-XRT refined Analysis
  95. GRB 210212A: BOOTES-4/MET optical upper limit
  96. GRB 210212A: Swift/UVOT Upper Limits
  97. GRB 210212A: Swift-BAT refined analysis
  98. GRB 210212A: Enhanced Swift-XRT position
  99. GRB 210212A: Swift detection of a burst
  100. GRB 210207B: GECAM detection

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