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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. GRB 170728B: LT afterglow confirmation
  2. GRB 170728B: NOT optical afterglow confirmation
  3. GRB 170728B: position of the TNG optical counterpart
  4. GRB 170728B: TNG optical afterglow candidate
  5. GRB 170728B: Swift detection of a short burst
  6. GRB 170728A: Swift-BAT refined analysis
  7. Swift triggers on a new galactic source: Swift J181723.1-164300
  8. GRB 170728A: Enhanced Swift-XRT position
  9. GRB 170728A: Swift detection of a burst
  10. GRB 170726A: Insight-HXMT detection
  11. GRB 170724A, Swift-BAT refined analysis
  12. GRB 170724A: Swift detection of a burst
  13. Fermi GBM trigger 522477026/170723188 is not a GRB
  14. Fermi GBM trigger 522470841/170723116 is not a GRB
  15. Fermi GBM trigger 522334209/170721535 is not a GRB
  16. GRB170714A: ATCA observation
  17. GRB 170714A: Bastille Day Burst redshift from OSIRIS/GTC
  18. Trigger 763539 from Swift is probably not astrophysical
  19. Fermi GBM trigger 522048561/170718229 is not a GRB
  20. GRB 170714A: NOEMA non-detection of the Bastille Day Burst
  21. LIGO/Virgo G275697: LOFAR follow-up
  22. GRB 170710B: Further Swift-XRT observations
  23. Correction to GCN Circular 21351: GRB 170714A: Swift/UVOT Observations
  24. GRB170714A: VLA Observations of the Bastille Day Ultra-long Burst
  25. GRB 170714A: Swift/UVOT Observations
  26. GRB 170714A: TNG NIR observations
  27. Fermi GBM trigger 521905898/170716577 is not a GRB
  28. GRB 170702A: AstroSat CZTI detection
  29. GRB 170714A, Swift-BAT refined analysis
  30. GRB 170714A: z-band afterglow candidate for OSIRIS/GTC
  31. GRB 170714A: Bastille Day Burst: ULGRB or RTDE?
  32. GRB 170714B: Insight-HXMT detection
  33. GRB 170714A: Swift-XRT refined Analysis
  34. Fermi GBM Detection of possible burst from AXP 4U 0142+61
  35. GRB 170714A: Enhanced Swift-XRT position
  36. GRB 170714A: Swift detection of a burst
  37. GRB 170712A: AstroSat CZTI detection
  38. Correction to GCN Circular 21337: GRB 170710D CALET Gamma-Ray Burst Monitor detection
  39. GRB 170710D CALET Gamma-Ray Burst Monitor detection
  40. GRB 170708B CALET Gamma-Ray Burst Monitor detection
  41. GRB 170703A CALET Gamma-Ray Burst Monitor detection
  42. GRB 170702A CALET Gamma-Ray Burst Monitor detection
  43. GRB 170711A: ISON/Terskol and AbAO optical observations
  44. GRB 170712A: Insight-HXMT detection
  45. GRB 170711A: Swift-BAT refined analysis
  46. Konus-Wind observation of GRB 170708A
  47. GRB 170711A: Swift/UVOT Upper Limits
  48. GRB 170711A: RATIR Optical and NIR Observations
  49. GRB 170705A: AstroSat CZTI detection
  50. GRB 170710C: a long GRB detected by INTEGRAL
  51. GRB 170711A: Swift-XRT refined Analysis
  52. GRB 170711A: Fermi GBM observation
  53. GRB 170711A: Enhanced Swift-XRT position
  54. GRB 170711A: Prompt enhanced Swift-XRT position
  55. GRB 170711A: Swift detection of a burst
  56. GRB 170705A: TShAO optical observations
  57. GRB 170710B: Fermi GBM observation
  58. GRB 170710B: Swift-XRT and UVOT observations
  59. GRB 170710B: Swift ToO observations
  60. GRB 170710B: Swift detection of a burst
  61. GRB170710A: Swift/UVOT detection
  62. IPN Triangulation of GRB 170708A (short)
  63. GRB 170710A: Swift-BAT refined analysis
  64. GRB 170710A: Swift-XRT refined Analysis
  65. GRB 170710A: Gemini-S candidate counterpart
  66. GRB 170710A: Enhanced Swift-XRT position
  67. GRB 170710A: Prompt enhanced Swift-XRT position
  68. GRB 170710A: Swift detection of a burst
  69. GRB 170708A: Insight-HXMT detection
  70. Correction to GCN Circular 21305: Trigger 760835: Swift misidentification of GRS1716-249
  71. Trigger 760835: Swift misidentification of GRS1716-249
  72. LIGO/Virgo G288732: Konus-Wind observations
  73. GRB 170705A: Further RATIR Optical and NIR Observations and Steepening of Fading
  74. GRB 170705A: KAIT Optical Observations
  75. GRB 170705A: Insight-HXMT observation
  76. GRB 170705A: ISON/Terskol optical observations
  77. Konus-Wind observation of GRB 170705A
  78. GRB 170705A: Redshift from 10.4m GTC/OSIRIS
  79. GRB 170705A: Fermi GBM observation
  80. GRB 170705A: Swift-BAT refined analysis
  81. GRB 170705A: MITSuME Akeno Optical Observation
  82. GRB 170705A: Swift/UVOT Detection
  83. GRB 170705A: RATIR Optical and NIR Observations
  84. GRB 170705A: Swift-XRT refined Analysis
  85. GRB 170705A: MASTER-OAFA early OT observations
  86. GRB 170705A: Enhanced Swift-XRT position
  87. GRB 170705A: Swift detection of a burst with an optical counterpart
  88. GRB 170629A: Swift-XRT refined Analysis
  89. GRB 170629A: Swift-BAT refined analysis
  90. GRB 170629A: Enhanced Swift-XRT position
  91. GRB 170629A: Fermi GBM observation
  92. LIGO/Virgo G274296: Updated localization from LIGO data
  93. GRB 170629A: Swift detection of a burst
  94. GRB 170626B CALET Gamma-Ray Burst Monitor detection
  95. LIGO/Virgo G270580: Candidate retracted due to H1 data quality
  96. Konus-Wind observation of GRB 170626B
  97. IPN Triangulation of GRB 170626B
  98. Konus-Wind observation of GRB 170626A
  99. GRB 170626A: SAO RAS confirmation of OT fading
  100. GRB 170626A: TShAO optical observations

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