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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

26042 results found.

  1. GRB 220427A: VLT/X-shooter photometry
  2. GRB 220426A: Swift-XRT and UVOT observations
  3. GRB 220423A: Detection by VZLUSAT-2
  4. Konus-Wind detection of GRB 220427A
  5. GRB 220427A: Swift-XRT refined Analysis
  6. GRB 220427A: Enhanced Swift-XRT position
  7. GRB 220426A: Tiled Swift observations
  8. GRB 220427A: Swift detection of a burst with an optical counterpart
  9. Konus-Wind detection of GRB 220426A
  10. IPN triangulation of GRB 220426A
  11. GRB 220426C: Swift/BAT-GUANO detection outside the coded FOV (short)
  12. GRB 220426A: Swift/BAT-GUANO detection outside the coded FOV
  13. GRB 220423A: Swift/BAT-GUANO detection outside the coded FOV
  14. GRB 220421A: Fermi GBM observation
  15. GRB 220421A: Swift/BAT-GUANO detection outside the coded FOV
  16. GRB 220418B: Swift-XRT observations
  17. GRB 220418B Fermi GBM observation
  18. GRB 220420A: Swift/BAT-GUANO detection outside the coded FOV
  19. GRB 220403C: Further Swift-XRT observations
  20. GRB 220418B: Swift ToO observations
  21. GRB 220417A: Fermi GBM detection
  22. GRB 220418B: Swift/BAT-GUANO refined location of a short burst
  23. GRB 220418B: Swift/BAT-GUANO candidate arcminute localization of a short burst
  24. GRB 220417A: Swift/BAT-GUANO detection outside the coded FOV
  25. GRB 220412B: Swift/UVOT Upper Limits
  26. GRB 220412B: Swift-BAT refined analysis
  27. Konus-Wind detection of GRB 220412B
  28. GRB 220412B: Fermi GBM observation
  29. Konus-Wind detection of GRB 220403C
  30. GRB 220412B: TNG optical observations
  31. GRB 220412A: GRANDMA observations
  32. GRB 220412A: Continued RATIR Observations and Steepening of the Light Curve
  33. GRB 220412A: BOOTES-network optical upper limits
  34. GRB 220412B: BOOTES-1 optical upper limit
  35. GRB 220412A: Swift-BAT refined analysis
  36. GRB 220412A: RATIR Observations of the Fading Afterglow
  37. GRB 220412B: Swift-XRT observations
  38. IPN triangulation of short/soft GRB 220406A
  39. Swift GRB 220412B: Global MASTER-Net observations report
  40. GRB 220408A: HCT optical upper limit
  41. GRB 220412B: GIT optical upper limit
  42. GRB 220412A: MITSuME Akeno optical upper limits
  43. Correction to GCN 31888: GRB 220412A: Swift-XRT refined Analysis
  44. GRB 220412B: MITSuME Akeno optical upper limits
  45. GRB 220412A: Swift-XRT refined Analysis
  46. GRB 220412A: Enhanced Swift-XRT position
  47. GRB 220412B: Swift detection of a short burst
  48. GRB 220412A: Swift/UVOT Upper Limits
  49. GRB 220408A: GRANDMA observations
  50. GRB 220403B: GRANDMA observations
  51. GRB 220412A: RATIR Afterglow Candidate
  52. GRB 220412A: Swift detection of a burst
  53. Swift GRB220412.28: Global MASTER-Net observations report
  54. IPN triangulation of GRB 220403C
  55. GRB 220403B: Swift/UVOT Detection
  56. GRB 220408A: Swift-BAT refined analysis
  57. GRB 220408A: RATIR Optical and NIR Observations
  58. GRB 220403B: 1.3m DFOT Optical upper limit
  59. GRB 220408A: 1.3m DFOT Optical upper limit
  60. GRB 220403C: Swift-XRT observations
  61. GRB 220408A: redshift lower limit estimating
  62. GRB 220408A: NOT optical observations and archival detection
  63. GRB 220408A: LCO Optical Afterglow Detection
  64. GRB 220408A: Swift-XRT refined Analysis
  65. GRB 220403C: Swift ToO observations
  66. GRB 220408A: BOOTES-5/JGT optical afterglow detection
  67. GRB 220408A: GIT optical upper limit
  68. GRB 220408A: Fermi GBM observation
  69. GRB 220408A: Swift/UVOT Detection
  70. GRB 220408A: Xinglong-2.16m optical upper limit
  71. GRB 220408A: Enhanced Swift-XRT position
  72. GRB 220408A: KAIT Optical Observations
  73. GRB 220408A: Swift detection of a burst with an optical counterpart, possibly associated with M51
  74. GRB 220403B: Mondy optical upper limit
  75. GRB 220403B: 1.5m OSN optical observation
  76. GRB 220404A: Swift-BAT refined analysis
  77. GRB 220403B: Kitab optical observations
  78. GRB 220403B: Swift-BAT refined analysis
  79. GRB 220403B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  80. GRB 220403B: Fermi GBM detection
  81. GRB 220404A: Swift detection of a burst
  82. GRB 220403B: Swift-XRT refined Analysis
  83. GRB 220403B: LBT observations
  84. Swift GRB 220403B: Global MASTER-Net observations report
  85. GRB 220403C (or A): Swift/BAT-GUANO detection outside the coded FOV
  86. GRB 220403B: Nanshan/NEXT optical afterglow power-law decay
  87. GRB 220403A: Tautenburg observations
  88. GRB 220403B: optical detection by D50
  89. GRB 220403B: Swift detection of a burst with an optical counterpart
  90. GRB 220401A: Swift/BAT-GUANO detection outside the coded FOV
  91. Swift Trigger 1100848 is likely not a GRB
  92. Swift GRB220402.16: Global MASTER-Net observations report
  93. GRB 220325A: GRANDMA observations
  94. GRB 220325A: Swift/UVOT Upper Limits
  95. GRB 211024B: Host galaxy redshift from X-shooter/VLT
  96. GRB 220325A: Swift-BAT refined analysis
  97. GRB 220325A: Tautenburg observations
  98. GRB 220325A: LCO Optical Upper Limits
  99. GRB 220325A: Swift-XRT refined Analysis
  100. GRB 220325A: 1.3m DFOT Optical upper limit

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