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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 220610A: Global MASTER-Net observations report
  2. GRB 220610A: Fermi GBM Final Real-time Localization
  3. Fermi trigger No 676537486: Global MASTER-Net observations report
  4. GRB 220609B: AstroSat CZTI detection
  5. GRB 220609B: CALET Gamma-Ray Burst Monitor detection
  6. Fermi trigger No 676366592: Global MASTER-Net observations report
  7. GRB 220608A: AstroSat CZTI detection
  8. GRB 220609A: Fermi GBM Final Real-time Localization
  9. GRB 220606A: Fermi GBM observation
  10. GRB 220606C: CALET Gamma-Ray Burst Monitor detection
  11. Fermi GRB 220608A: Global MASTER-Net observations report
  12. GRB 220608A: Fermi GBM Final Real-time Localization
  13. GRB 220606B: Gemini South Optical Observations
  14. MAXI GRB220607.31: Global MASTER-Net observations report
  15. MAXI GRB220607.41: Global MASTER-Net observations report
  16. GRB 220606B: Fermi GBM Observation
  17. GRB 220606B: Swift follow-up observations
  18. Konus-Wind detection of GRB 220601A
  19. GRB 220606A: Swift/BAT-GUANO detection
  20. GRB 220606B: GUANO coordinate correction to GCN 32167
  21. GRB 220527A: A BdHN I with a clear UPE phase
  22. GRB 220606B: Swift ToO observations
  23. GRB 220606B: Swift/BAT-GUANO candidate arcminute localization of a short burst
  24. Fermi GRB 220606B: Global MASTER-Net observations report
  25. GRB 220606B: Fermi GBM Final Real-time Localization
  26. GRB 220606A: Fermi GBM Final Real-time Localization
  27. IPN triangulation of GRB 220601A (long)
  28. Fermi trigger No 675992935: Global MASTER-Net observations report
  29. GRB 220603A: Swift/BAT-GUANO detection outside the coded FOV
  30. Fermi-GBM will trial new SAA regions from Tuesday June 7th
  31. GRB 220527A: MITSuME Akeno continued optical observation
  32. GRB 220527A: Lick 3m Optical Observations
  33. Konus-Wind detection of GRB 220528A
  34. IPN triangulation of GRB 220528A (short)
  35. GRB 220528A: Fermi GBM Observation
  36. Trigger 1108538: Swift detection of a burst from SGR J1935+2154
  37. Fermi GRB 220530A: Global MASTER-Net observations report
  38. Konus-Wind observation of GRB 220527A
  39. Swift trigger 1108515 is not an astrophysical event
  40. GRB 220530A: Fermi GBM Final Real-time Localization
  41. Correction to GCN 32148: Should be GRB 220528A
  42. GRB 220528B: Swift/BAT-GUANO detection outside the coded FOV
  43. GRB 220528A: Fermi GBM Final Localization
  44. GRB 220527A: AST3-3 Yaoan Optical Observation
  45. GRB 220527A: REM optical/NIR observations
  46. GRB 220527A: VLT/X-shooter spectroscopic redshift
  47. GRB 220527A: MeerLICHT afterglow observations
  48. Fermi trigger No 675411172: Global MASTER-Net observations report
  49. GRB 220527A: NOT optical photometry and spectroscopic redshift
  50. GRB 220527A: AstroSat CZTI detection
  51. GRB 220527A: CALET Gamma-Ray Burst Monitor detection
  52. GRB 220527A: MITSuME Akeno optical observation
  53. LAT GRB220527.39: Global MASTER-Net observations report
  54. GRB 220527A: Swift/UVOT detection
  55. GRB 220527A: Swift-XRT afterglow detection
  56. Swift trigger 1108208 is not an interesting astrophysical event.
  57. GRB 220527A: Fermi GBM Observation
  58. GRB 220527A: Swift ToO observations
  59. GRB 220527A: Fermi-LAT detection
  60. GRB 220527A: Fermi GBM Final Localization
  61. GRB 220527A: AGILE detection
  62. GRB 220521B: CALET Gamma-Ray Burst Monitor detection
  63. GRB 220525A: Fermi GBM Detection
  64. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 May 25
  65. GRB 220525A: CALET Gamma-Ray Burst Monitor detection
  66. GRB 220523B: CALET Gamma-Ray Burst Monitor detection
  67. Konus-Wind detection of GRB 220524B
  68. Konus-Wind detection of GRB 220525A
  69. Konus-Wind detection of GRB 220524A
  70. Swift GRB220526.48: Global MASTER-Net observations report
  71. Fermi GRB 220525A: Global MASTER-Net observations report
  72. IPN triangulation of GRB 220525A
  73. IPN triangulation of GRB 220524B
  74. Fermi-LAT Gamma-ray Observations of IceCube-220524A
  75. IPN triangulation of GRB 220524A
  76. IceCube-220524A: Upper limits from a search for additional neutrino events in IceCube
  77. GRB 220525A: BALROG localization (Fermi Trigger 675130259 / GRB 220525008)
  78. GRB 220525A: Fermi GBM Final Real-time Localization
  79. GRB 220521A: ATCA detection
  80. GRB 220521A: ALMA detection
  81. Konus-Wind detection of GRB 220522B
  82. IPN triangulation of GRB 220522B
  83. GRB 220521A: BOOTES-2/TELMA and CAHA 2.2m telescope optical upper limit
  84. Konus-Wind detection of GRB 220521B
  85. GRB 220521A: classification and detection by SPI-ACS/INTEGRAL
  86. IPN triangulation of GRB 220521B
  87. GRB 220521A: ISON-Castelgrande observatory optical observations
  88. IceCube-220524A - IceCube observation of a high-energy neutrino candidate track-like event
  89. GRB 220521A: MITSuME Akeno optical upper limits
  90. Fermi GRB 220523B: Global MASTER-Net observations report
  91. GRB 220521A: Gemini Observations
  92. GRB 220523B: Fermi GBM detection
  93. GRB 220521A: MMT Afterglow Imaging
  94. GRB 220521A: REM optical/NIR upper limits
  95. GRB 220514A: Swift/BAT-GUANO detection outside the coded FOV
  96. VLA observations of GW170817 at ~4.8 years after the merger
  97. Fermi GRB 220523A: Global MASTER-Net observations report
  98. GRB 220523A: Fermi GBM Final Real-time Localization
  99. GRB 220521A: LCO Optical Detection
  100. GRB 220521A: Swift-BAT refined analysis

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