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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"

34115 results found.

  1. GRB 220426A: BALROG localization (Fermi Trigger 672648596/ GRB 220426285)
  2. Correction to 31937: GRB 220421B: Detection by VZLUSAT-2
  3. GRB 220423A: Swift/BAT-GUANO detection outside the coded FOV
  4. On the AGILE detection of GRB 220423A
  5. GRB 220423A: AGILE detection
  6. GRB 220421B: Detection by VZLUSAT-2
  7. GRB 220421A: Fermi GBM observation
  8. GRB 220421A: Swift/BAT-GUANO detection outside the coded FOV
  9. Fermi GBM trigger 672128054/220420260 is not a GRB
  10. GRB 220418B: Swift-XRT observations
  11. GRB 220418B Fermi GBM observation
  12. “GRB 220420A” is not a GRB
  13. GRB 220420A: Swift/BAT-GUANO detection outside the coded FOV
  14. GRB 220403C: Further Swift-XRT observations
  15. GRB 220418B: Swift ToO observations
  16. GRB 220417A: Fermi GBM detection
  17. GRB 220418B: Swift/BAT-GUANO refined location of a short burst
  18. IPN triangulation of GRB 220411A
  19. GRB 220418B: Swift/BAT-GUANO candidate arcminute localization of a short burst
  20. GRB 220417A: Swift/BAT-GUANO detection outside the coded FOV
  21. GRB 220412B: Swift/UVOT Upper Limits
  22. Fermi GRB 220418A: Global MASTER-Net observations report
  23. GRB 220418B: Fermi GBM Final Real-time Localization
  24. GRB 220418A: Fermi GBM Final Real-time Localization
  25. Fermi GRB 220417A: Global MASTER-Net observations report
  26. GRB 220417A: Fermi GBM Final Real-time Localization
  27. GRB 220412B: Swift-BAT refined analysis
  28. Konus-Wind detection of GRB 220412B
  29. GRB 220412B: Fermi GBM observation
  30. Konus-Wind detection of GRB 220403C
  31. GRB 220408B: Fermi GBM observation
  32. Konus-Wind detection of GRB 220408B
  33. GRB 220412B: TNG optical observations
  34. GRB 220412A: GRANDMA observations
  35. GRB 220412A: Continued RATIR Observations and Steepening of the Light Curve
  36. GRB 220412A: BOOTES-network optical upper limits
  37. GRB 220412B: BOOTES-1 optical upper limit
  38. GRB 220412A: Swift-BAT refined analysis
  39. GRB 220412A: RATIR Observations of the Fading Afterglow
  40. GRB 220412B: Swift-XRT observations
  41. GRB 220408B: Fermi-LAT detection
  42. IPN triangulation of short/soft GRB 220406A
  43. Swift GRB 220412B: Global MASTER-Net observations report
  44. GRB 220408A: HCT optical upper limit
  45. GRB 220412B: GIT optical upper limit
  46. GRB 220412A: MITSuME Akeno optical upper limits
  47. Correction to GCN 31888: GRB 220412A: Swift-XRT refined Analysis
  48. GRB 220412B: MITSuME Akeno optical upper limits
  49. GRB 220412A: Swift-XRT refined Analysis
  50. GRB 220412A: Enhanced Swift-XRT position
  51. GRB 220412B: Swift detection of a short burst
  52. GRB 220412A: Swift/UVOT Upper Limits
  53. GRB 220408A: GRANDMA observations
  54. GRB 220403B: GRANDMA observations
  55. GRB 220412A: RATIR Afterglow Candidate
  56. GRB 220412A: Swift detection of a burst
  57. GRB 220411A: AstroSat CZTI detection
  58. IPN triangulation of GRB 220408B
  59. IPN triangulation of GRB 220403C
  60. GRB 220403B: Swift/UVOT Detection
  61. GRB 220408A: Lowell Discovery Telescope Optical Observations
  62. GRB 220408A: Swift-BAT refined analysis
  63. Fermi GRB 220411A: Global MASTER-Net observations report
  64. GRB 220411A: BALROG localization (Fermi Trigger 671354405/ GRB 220411306)
  65. GRB 220411A: Fermi GBM Final Real-time Localization
  66. GRB 220408A: RATIR Optical and NIR Observations
  67. GRB 220403B: 1.3m DFOT Optical upper limit
  68. GRB 220408A: 1.3m DFOT Optical upper limit
  69. GRB 220408A: LOAO, DOAO, and, SAO optical upper limit
  70. GRB 220403C: Swift-XRT observations
  71. GRB 220408A: redshift lower limit estimating
  72. GRB 220408A: NOT optical observations and archival detection
  73. GRB 220408B: AstroSat CZTI detection
  74. GRB 220408A: LCO Optical Afterglow Detection
  75. GRB 220408A: Swift-XRT refined Analysis
  76. GRB 220403C: Swift ToO observations
  77. GRB 220408A: BOOTES-5/JGT optical afterglow detection
  78. Fermi GRB 220408B: Global MASTER-Net observations report
  79. GRB 220408A: GIT optical upper limit
  80. GRB 220408A: Fermi GBM observation
  81. GRB 220408A: Swift/UVOT Detection
  82. GRB 220408B: Fermi GBM Final Localization
  83. GRB 220408A: Xinglong-2.16m optical upper limit
  84. GRB 220408A: Enhanced Swift-XRT position
  85. Chandra upper limit at the location of GRB 220408A
  86. GRB 220408A: KAIT Optical Observations
  87. Fermi GRB 220408A: Global MASTER-Net observations report
  88. GRB 220408A: Swift detection of a burst with an optical counterpart, possibly associated with M51
  89. GRB 220408A: Fermi GBM Final Real-time Localization
  90. ZTF22aaajecp/AT2022cmc: continued optical observations (Mondy, SAO RAS, CrAO)
  91. GRB 220403B: Mondy optical upper limit
  92. GRB 220403B: 1.5m OSN optical observation
  93. GRB 220404A: Swift-BAT refined analysis
  94. GRB 220403B: Kitab optical observations
  95. GRB 220405A: Fermi GBM Final Localization
  96. GRB 220403B: Swift-BAT refined analysis
  97. GRB 220404B: Fermi GBM Final Real-time Localization
  98. GRB 220403B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  99. GRB 220403B: Fermi GBM detection
  100. GRB 220404A: Swift detection of a burst

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