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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"

27970 results found.

  1. ZTF21aayokph (AT2021lfa): Redshift from Gemini South
  2. GRB 210504A: VLT X-shooter redshift
  3. GRB 210424B: AstroSat CZTI detection
  4. GRB 210504A: Swift-XRT refined Analysis
  5. GRB 210504A: Swift-BAT refined analysis
  6. ZTF and LT observations of ZTF21aayokph (AT2021lfa), a fast-fading red transient
  7. GRB 210504A: NOT optical afterglow detection
  8. GRB 210504A: AST3-3 YaoAn Optical Upper Limit
  9. GRB 210504A: Swift/UVOT Detection
  10. GRB 210504A: BOOTES-4/MET optical upper limit
  11. Swift GRB210504.58: Global MASTER-Net observations report
  12. GRB 210504A: update on the BAT trigger time and burst duration
  13. GRB 210504A: Swift detection of a burst
  14. GRB 210503A: Fermi GBM Final Real-time Localization
  15. Swift GRB210502.74: Global MASTER-Net observations report
  16. Swift Detection of MAXI J1803-298 including an optical counterpart
  17. GRB 210430A: BOOTES-1 optical limit
  18. GRB 210424B: MITSuME Akeno optical upper limits
  19. GRB 210501A: Fermi GBM Final Real-time Localization
  20. GRB 210430A: Swift-BAT refined analysis
  21. GRB 210430B: Fermi GBM Final Real-time Localization
  22. Swift GRB210430.45: Global MASTER-Net observations report
  23. GRB 210430A: Swift detection of a burst
  24. GRB 210424B: CALET Gamma-Ray Burst Monitor detection
  25. GRB 210413B: Swift/UVOT Observations
  26. Konus-Wind detection of GRB 210424B
  27. Delayed GRB GCN Notices from Swift
  28. GRB 210323B: Swift-XRT observations
  29. Swift Trigger 1045571 is not a GRB
  30. GRB 210427A: GECAM detection
  31. GRB 210427A: Fermi GBM Final Real-time Localization
  32. GRB 210422B: Fermi GBM Final Localization
  33. GRB 210425A: GECAM detection
  34. GRB 210422A: Swift-BAT refined analysis
  35. GRB 210424A: Fermi GBM Final Real-time Localization
  36. GRB 210421A: Swift-BAT refined analysis
  37. GRB 210421B: Swift-XRT observations
  38. GRB 210421B: AstroSat CZTI detection
  39. GRB 210421A: GECAM detection
  40. GRB 210421B: AstroSat CZTI detection
  41. Swift GRB210422.74: Global MASTER-Net observations report
  42. GRB 210422A: Swift detection of a burst
  43. GRB 210421A: Swift/UVOT Upper Limits
  44. GRB 210421A: MITSuME Akeno optical upper limits
  45. GRB 210419B: AstroSat CZTI detection
  46. GRB 210420B: Swift-BAT refined analysis
  47. GRB 210421B: Swift ToO observations
  48. GRB 210421B: Swift/BAT-GUANO detection and arcminute localization
  49. GRB 210420B: Swift-XRT refined Analysis
  50. GRB 210421A: Swift-XRT refined Analysis
  51. GRB 210421C: Fermi GBM Final Real-time Localization
  52. GRB 210421B: Fermi GBM Final Localization
  53. GRB 210419C: Swift/UVOT Upper Limits
  54. GRB 210420B: Ondrejov D50 optical afterglow detection
  55. GRB 210421A: Enhanced Swift-XRT position
  56. GRB 210420B: Swift/UVOT Detection
  57. GRB 210420B: KAIT Optical Observations
  58. GRB 210419C: MITSuME Akeno optical upper limits
  59. GRB 210420B: DDOTI Detection of the Afterglow
  60. GRB 210421A: DDOTI Upper Limit
  61. GRB 210419C: Swift-BAT refined analysis
  62. GRB 210420B: update on the BAT trigger time
  63. GRB 210420B: Montarrenti Observatory optical afterglow detection
  64. Swift GRB 210421A: Global MASTER-Net observations report
  65. GRB 210421A: Swift detection of a burst
  66. GRB 210420B: AST3-3 YaoAn Optical Observation
  67. GRB 210420B: BOOTES-4/MET optical afterglow detection
  68. GRB 210420B: Optical observations
  69. GRB 210420B: MASTER optical counterpart detection
  70. GRB 210420B: Swift detection of a burst
  71. GRB 210419C: Montarrenti Observatory Upper Limit
  72. GRB 210419A: Swift/UVOT Upper Limits
  73. GRB 210419C: KAIT Optical Upper Limit
  74. GRB 210419C: Enhanced Swift-XRT position
  75. GRB 210419A: Swift-BAT refined analysis
  76. GRB 210420A: Fermi GBM Final Real-time Localization
  77. Swift GRB210419.98: Global MASTER-Net observations report
  78. GRB 210419A: Swift-XRT refined Analysis
  79. GRB 210419C: Swift detection of a burst
  80. Swift GRB 210419A: Global MASTER-Net observations report
  81. GRB 210419B: Fermi GBM Final Real-time Localization
  82. GRB 210419A: Enhanced Swift-XRT position
  83. GRB 210419A: LCO Optical Upper Limit
  84. GRB 210419A: Swift detection of a burst
  85. GRB 210413B: Swift-XRT observations
  86. GRB 210413B: LOAO optical upper limit
  87. GRB 210411C: A very significant early X-ray afterglow
  88. GRB 210413B: Swift ToO observations
  89. GRB 210413B: Swift/BAT detection and probable localization of a short burst
  90. GRB 210411B: AstroSat CZTI detection
  91. GRB 210410A: AstroSat CZTI detection
  92. GRB 210410A: A twin of short GRB 090510 with complementary observations
  93. GRB 210415A: Fermi GBM Final Real-time Localization
  94. GRB 210413A: GECAM detection
  95. GRB 210410A: Swift/UVOT Upper Limits (revision)
  96. GRB 210411C: Swift/UVOT Detection
  97. GRB 210411C: Swift-BAT refined analysis
  98. GRB 210411C: Chilescope optical observations
  99. GRB 210411C: Swift-XRT refined Analysis
  100. GRB 210411C: VLT/X-shooter redshift

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