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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 180210A: Tiled Swift observations
  2. GRB 180205A: BAO optical observations
  3. Retraction of Swift trigger 809374
  4. GRB 180210A: Swift ToO observations
  5. GRB 180210A: Fermi-LAT detection
  6. GRB 180210A: Fermi GBM detection
  7. Trigger 809374: Swift detection of a possible non-burst faint source
  8. Trigger 809217: Swift trigger on RS CVn Star HD 8357
  9. GRB180205A: Optical observations with DOAO 1m telescope
  10. GRB 180205A: AbAO optical observations
  11. Fermi-GBM Detection of possible burst from AXP CXOU J164710.2-455216/PSR J1647-4552
  12. GRB 180205A optical observations
  13. GRB 180202A: Insight-HXMT/HE detection
  14. GRB 180204A: MITSuME Okayama optical upper limits
  15. GRB 180205A: confirmation of Swift-BAT trigger time.
  16. GRB 180205A: Optical observations
  17. GRB 180205A: Swift/UVOT Detection
  18. GRB 180205A: Nanshan-1m optical observations
  19. GRB 180205A: Swift-XRT refined Analysis
  20. GRB 180205A: Swift-BAT refined analysis
  21. GRB 180205A: Xinglong TNT optical observation
  22. GRB 180205A: Further GROND Observations reveal Afterglow is still bright
  23. GRB 180205A: Nickel telescope optical observations
  24. Swift Trigger on AXP CXOU J164710.2-455216/PSR J1647-4552
  25. GRB 180205A: VLT polarimetry
  26. GRB 180205A: Mondy optical observations
  27. GRB 180205A: Fermi GBM observation
  28. Konus-Wind observation of GRB 180204A
  29. GRB 180205A: VLT/X-shooter redshift
  30. GRB 180205A: GROND detection of the NIR/optical afterglow
  31. GRB 180205A: KAIT optical afterglow confirmation
  32. GRB 180205A: Swift detection of a burst with a bright optical counterpart
  33. GRB 180204A: Swift-BAT refined analysis
  34. GRB 180204A: Swift/UVOT Upper Limits
  35. GRB 180204A: Fermi GBM detection
  36. GRB 180204A: Enhanced Swift-XRT position
  37. GRB 180204A: Swift-XRT refined Analysis
  38. GRB 180204A: Swift detection of a short burst
  39. GW170817/GRB170817A: Updated results from the full Chandra dataset
  40. GRB 180126A CALET Gamma-Ray Burst Monitor detection
  41. GW170817/GRB170817A: Preliminary results of Chandra monitoring
  42. LIGO/Virgo GW170817: Chandra X-ray Emission Continues to Rise ~156 Days Post-Merger
  43. GRB 180120A: AstroSat CZTI detection
  44. Fermi GBM trigger 538030981/180119210 is not a GRB
  45. LIGO/Virgo G298048 GRAWITA: VST-ESO PARANAL follow up of AT2017gfo
  46. GRB 180120A: Fermi GBM Detection
  47. GRB 180120A CALET Gamma-Ray Burst Monitor detection
  48. Fermi GBM trigger 538316685/180122517 is not a GRB
  49. GRB 180113B: AstroSat CZTI detection
  50. GRB 180113A: AstroSat CZTI detection
  51. GRB 180115A: SEDM Observations
  52. GRB 180116A CALET Gamma-Ray Burst Monitor detection
  53. Konus-Wind observation of GRB 171209A
  54. GRB 180113A CALET Gamma-Ray Burst Monitor detection
  55. GRB 180112A CALET Gamma-Ray Burst Monitor detection
  56. GRB 180115A: Swift/UVOT Detection
  57. GRB 180116A: Fermi GBM Detection
  58. Konus-Wind observation of GRB 180113B
  59. IPN Triangulation of GRB 180113B
  60. GRB 180112A: Insight-HXMT/HE detection/observation
  61. GRB 180111A AROMA-N optical observation
  62. Konus-Wind observation of GRB 180113C
  63. e-MERLIN detection of GRB 171205A
  64. IPN Triangulation of GRB 180113C
  65. GRB 180115A: Swift-BAT refined analysis
  66. GRB 180116A: MAXI/GSC detection
  67. GRB 180115A: Redshift from OSIRIS/GTC
  68. GRB 180115A: NOT detection of optical counterpart
  69. Konus-Wind observation of GRB 180113A
  70. GRB 180113C: Insight-HXMT/HE observation
  71. GRB 180113B: Insight-HXMT/HE observation
  72. GRB 180111A: Insight-HXMT/HE observation
  73. GRB 180115A: MITSuME Akeno optical upper limits
  74. GRB 180113A: Swift ToO observations
  75. GRB 180115A: Swift-XRT refined Analysis
  76. GRB 180115A: Enhanced Swift-XRT position
  77. Konus-Wind observation of GRB 180111A
  78. GRB 180115A: Swift detection of a burst with an optical counterpart.
  79. GRB 180113C: Fermi GBM detection
  80. GRB 180111A CALET Gamma-Ray Burst Monitor detection
  81. GRB 180113A: Swift-BAT refined analysis
  82. GRB 180111A: AbAO optical observations
  83. GRB 180113A: KAIT Optical Observations
  84. GRB 180113B: Fermi GBM detection
  85. GRB 180113A: Fermi GBM observation
  86. GRB 180111A: Swift/UVOT Detection
  87. GRB 180103A: Swift-XRT afterglow detection
  88. GRB 180113A: Swift detection of a burst
  89. GRB 180111A: Swift-BAT refined analysis
  90. GRB 180111A: RATIR Optical and NIR Observations
  91. GRB 180111A: Swift-XRT refined Analysis
  92. GRB 180111A: AGILE/MCAL detection
  93. GRB180111A: Xinglong TNT possible optical detection
  94. GRB 180111A: Enhanced Swift-XRT position
  95. GRB 180111A: Swift detection of a burst with an optical counterpart
  96. Correction to GCN Circular 22316: GRB 171230B: Insight-HXMT detection
  97. GRB 171230B: Insight-HXMT/HE detection
  98. GRB 180103A: LCO Sutherland 1-m telescope observations
  99. Konus-Wind observation of GRB 180103A
  100. GRB 171227A: AstroSat CZTI detection

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