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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"
  1. Fermi GRB 220617A: Global MASTER-Net observations report
  2. GRB 220617A: Fermi GBM Final Real-time Localization
  3. GRB 220611A: Gemini Ks counterpart detection
  4. Fermi trigger No 677174940: Global MASTER-Net observations report
  5. Konus-Wind detection of GRB 220613A
  6. IPN triangulation of GRB 220613A
  7. Konus-Wind detection of an intermediate flare from SGR 1935+2154 on June 16
  8. GRB 220611A: Gemini South Infrared Detection
  9. IPN triangulation of GRB 220606C
  10. GRB 220611A: Swift/UVOT Upper Limits
  11. Fermi trigger No 676909037: Global MASTER-Net observations report
  12. GRB 220612A: CALET Gamma-Ray Burst Monitor detection
  13. GRB 220612A: Swift/BAT-GUANO detection
  14. GRB 220611A: Swift-BAT refined analysis
  15. GRB 220608B: Detection by VZLUSAT-2
  16. Swift GRB 220611A: Global MASTER-Net observations report
  17. GRB 220611A: Swift-XRT refined Analysis
  18. GRB 220610B: AstroSat CZTI detection
  19. GRB 220611A: Enhanced Swift-XRT position
  20. GRB 220611A: Swift detection of a burst
  21. IPN triangulation of GRB 220609B
  22. Fermi GRB 220610A: Global MASTER-Net observations report
  23. GRB 220610A: Fermi GBM Final Real-time Localization
  24. Fermi trigger No 676537486: Global MASTER-Net observations report
  25. GRB 220609B: AstroSat CZTI detection
  26. GRB 220609B: CALET Gamma-Ray Burst Monitor detection
  27. Fermi trigger No 676366592: Global MASTER-Net observations report
  28. GRB 220608A: AstroSat CZTI detection
  29. GRB 220609A: Fermi GBM Final Real-time Localization
  30. GRB 220606A: Fermi GBM observation
  31. GRB 220606C: CALET Gamma-Ray Burst Monitor detection
  32. Fermi GRB 220608A: Global MASTER-Net observations report
  33. GRB 220608A: Fermi GBM Final Real-time Localization
  34. GRB 220606B: Gemini South Optical Observations
  35. MAXI GRB220607.31: Global MASTER-Net observations report
  36. MAXI GRB220607.41: Global MASTER-Net observations report
  37. GRB 220606B: Fermi GBM Observation
  38. GRB 220606B: Swift follow-up observations
  39. Konus-Wind detection of GRB 220601A
  40. GRB 220606A: Swift/BAT-GUANO detection
  41. GRB 220606B: GUANO coordinate correction to GCN 32167
  42. GRB 220527A: A BdHN I with a clear UPE phase
  43. GRB 220606B: Swift ToO observations
  44. GRB 220606B: Swift/BAT-GUANO candidate arcminute localization of a short burst
  45. Fermi GRB 220606B: Global MASTER-Net observations report
  46. GRB 220606B: Fermi GBM Final Real-time Localization
  47. GRB 220606A: Fermi GBM Final Real-time Localization
  48. IPN triangulation of GRB 220601A (long)
  49. Fermi trigger No 675992935: Global MASTER-Net observations report
  50. GRB 220603A: Swift/BAT-GUANO detection outside the coded FOV
  51. Fermi-GBM will trial new SAA regions from Tuesday June 7th
  52. GRB 220527A: MITSuME Akeno continued optical observation
  53. GRB 220527A: Lick 3m Optical Observations
  54. Konus-Wind detection of GRB 220528A
  55. IPN triangulation of GRB 220528A (short)
  56. GRB 220528A: Fermi GBM Observation
  57. Trigger 1108538: Swift detection of a burst from SGR J1935+2154
  58. Fermi GRB 220530A: Global MASTER-Net observations report
  59. Konus-Wind observation of GRB 220527A
  60. Swift trigger 1108515 is not an astrophysical event
  61. GRB 220530A: Fermi GBM Final Real-time Localization
  62. Correction to GCN 32148: Should be GRB 220528A
  63. GRB 220528B: Swift/BAT-GUANO detection outside the coded FOV
  64. GRB 220528A: Fermi GBM Final Localization
  65. GRB 220527A: AST3-3 Yaoan Optical Observation
  66. GRB 220527A: REM optical/NIR observations
  67. GRB 220527A: VLT/X-shooter spectroscopic redshift
  68. GRB 220527A: MeerLICHT afterglow observations
  69. Fermi trigger No 675411172: Global MASTER-Net observations report
  70. GRB 220527A: NOT optical photometry and spectroscopic redshift
  71. GRB 220527A: AstroSat CZTI detection
  72. GRB 220527A: CALET Gamma-Ray Burst Monitor detection
  73. GRB 220527A: MITSuME Akeno optical observation
  74. LAT GRB220527.39: Global MASTER-Net observations report
  75. GRB 220527A: Swift/UVOT detection
  76. GRB 220527A: Swift-XRT afterglow detection
  77. Swift trigger 1108208 is not an interesting astrophysical event.
  78. GRB 220527A: Fermi GBM Observation
  79. GRB 220527A: Swift ToO observations
  80. GRB 220527A: Fermi-LAT detection
  81. GRB 220527A: Fermi GBM Final Localization
  82. GRB 220527A: AGILE detection
  83. GRB 220521B: CALET Gamma-Ray Burst Monitor detection
  84. GRB 220525A: Fermi GBM Detection
  85. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 May 25
  86. GRB 220525A: CALET Gamma-Ray Burst Monitor detection
  87. GRB 220523B: CALET Gamma-Ray Burst Monitor detection
  88. Konus-Wind detection of GRB 220524B
  89. Konus-Wind detection of GRB 220525A
  90. Konus-Wind detection of GRB 220524A
  91. Swift GRB220526.48: Global MASTER-Net observations report
  92. Fermi GRB 220525A: Global MASTER-Net observations report
  93. IPN triangulation of GRB 220525A
  94. IPN triangulation of GRB 220524B
  95. Fermi-LAT Gamma-ray Observations of IceCube-220524A
  96. IPN triangulation of GRB 220524A
  97. IceCube-220524A: Upper limits from a search for additional neutrino events in IceCube
  98. GRB 220525A: BALROG localization (Fermi Trigger 675130259 / GRB 220525008)
  99. GRB 220525A: Fermi GBM Final Real-time Localization
  100. GRB 220521A: ATCA detection

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