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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"

26127 results found.

  1. GRB 210504A: update on the BAT trigger time and burst duration
  2. GRB 210504A: Swift detection of a burst
  3. Swift GRB210502.74: Global MASTER-Net observations report
  4. Swift Detection of MAXI J1803-298 including an optical counterpart
  5. GRB 210430A: BOOTES-1 optical limit
  6. GRB 210430A: Swift-BAT refined analysis
  7. Swift GRB210430.45: Global MASTER-Net observations report
  8. GRB 210430A: Swift detection of a burst
  9. GRB 210413B: Swift/UVOT Observations
  10. Delayed GRB GCN Notices from Swift
  11. GRB 210323B: Swift-XRT observations
  12. Swift Trigger 1045571 is not a GRB
  13. GRB 210420B: Assy optical observations
  14. GRB 210424.694: DDOTI Upper Limits on the Afterglow
  15. GRB 210422A: Swift-BAT refined analysis
  16. GRB 210420B: follow-up photometry of optical afterglow at INASAN/Simeiz
  17. GRB 210420B: Zeiss-1000 of Koshka optical observations
  18. GRB 210421A: Swift-BAT refined analysis
  19. GRB 210421B: Swift-XRT observations
  20. GRB 210421B: AstroSat CZTI detection
  21. GRB 210420B: continued Tautenburg observations
  22. GRB 210421A: GECAM detection
  23. GRB 210421B: AstroSat CZTI detection
  24. Swift GRB210422.74: Global MASTER-Net observations report
  25. GRB 210422A: Swift detection of a burst
  26. GRB 210421A: Swift/UVOT Upper Limits
  27. GRB 210420B: follow-up photometry of the optical afterglow at Konkoly
  28. GRB 210421A: MITSuME Akeno optical upper limits
  29. GRB 210420B: Swift-BAT refined analysis
  30. GRB 210421B: Swift ToO observations
  31. GRB 210421B: Swift/BAT-GUANO detection and arcminute localization
  32. GRB 210420B: Swift-XRT refined Analysis
  33. GRB 210421A: Swift-XRT refined Analysis
  34. GRB 210420B: Montarrenti Observatory follow-up observations
  35. GRB 210419C: Swift/UVOT Upper Limits
  36. GRB 210420B: Ondrejov D50 optical afterglow detection
  37. GRB 210421A: Enhanced Swift-XRT position
  38. GRB 210420B: Tautenburg observations
  39. GRB 210420B: Swift/UVOT Detection
  40. GRB 210420B: KAIT Optical Observations
  41. GRB 210419C: MITSuME Akeno optical upper limits
  42. GRB 210420B: DDOTI Detection of the Afterglow
  43. GRB 210421A: DDOTI Upper Limit
  44. GRB 210419C: Swift-BAT refined analysis
  45. GRB 210420B: update on the BAT trigger time
  46. GRB 210420B: Redshift from GTC
  47. GRB 210420B: Multiband photometry from NOT
  48. GRB 210420B: Montarrenti Observatory optical afterglow detection
  49. Swift GRB 210421A: Global MASTER-Net observations report
  50. GRB 210421A: Swift detection of a burst
  51. GRB 210420B: AST3-3 YaoAn Optical Observation
  52. GRB 210420B: BOOTES-4/MET optical afterglow detection
  53. GRB 210420B: Optical observations
  54. GRB 210420B: MASTER optical counterpart detection
  55. GRB 210420B: Swift detection of a burst
  56. GRB 210419C: RATIR Optical and NIR Upper Limits
  57. GRB 210419C: Montarrenti Observatory Upper Limit
  58. GRB 210419A: Swift/UVOT Upper Limits
  59. GRB 210419C: KAIT Optical Upper Limit
  60. GRB 210419C: Enhanced Swift-XRT position
  61. GRB 210419A: Swift-BAT refined analysis
  62. Swift GRB210419.98: Global MASTER-Net observations report
  63. GRB 210419A: Swift-XRT refined Analysis
  64. GRB 210419C: Swift detection of a burst
  65. Swift GRB 210419A: Global MASTER-Net observations report
  66. GRB 210419A: Enhanced Swift-XRT position
  67. GRB 210419A: LCO Optical Upper Limit
  68. GRB 210419A: Swift detection of a burst
  69. GRB 210413B: Swift-XRT observations
  70. GRB 210413B: LOAO optical upper limit
  71. GRB 210411C: A very significant early X-ray afterglow
  72. GRB 210413B: Swift ToO observations
  73. GRB 210413B: Swift/BAT detection and probable localization of a short burst
  74. GRB 210410A: AstroSat CZTI detection
  75. GRB 210410A: A twin of short GRB 090510 with complementary observations
  76. GRB 210410A: Swift/UVOT Upper Limits (revision)
  77. GRB 210411C: Swift/UVOT Detection
  78. GRB 210411C: Swift-BAT refined analysis
  79. GRB 210411C: Chilescope optical observations
  80. GRB 210411C: ePESSTO+ NTT optical observations
  81. GRB 210411C: Swift-XRT refined Analysis
  82. GRB 210411C: VLT/X-shooter redshift
  83. GRB 210410A: MITSuME Akeno optical upper limits
  84. Swift GRB 210411C: Global MASTER-Net observations report
  85. GRB 210411C: BOOTES-4/MET optical upper limit
  86. GRB 210411C: LCO Optical Afterglow Candidate
  87. GRB 210411C: Enhanced Swift-XRT position
  88. GRB 210406A: 10.4m GTC follow-up observation
  89. Konus-Wind detection of GRB 210410A
  90. GRB 210411C: Swift detection of a burst with an optical counterpart
  91. GRB 210410A: Swift-BAT refined analysis
  92. GRB 210410A: Swift-XRT refined Analysis
  93. GRB 210410A: Fermi GBM detection
  94. GRB 210410A: Swift/UVOT Upper Limits
  95. GRB210410A: Joint inspection of RATIR and D50 data
  96. GRB 210406A: Swift-XRT observations
  97. GRB 210410A: RATIR Optical and NIR Observations
  98. GRB 210410A: AGILE detection of a burst
  99. GRB 210410A: Fermi-LAT detection
  100. GRB210410A: Candidate optical afterglow by Ondrejov D50

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