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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 180624A: Swift detection of a burst
  2. GRB 180623A: Swift/UVOT Detection
  3. GRB 180623A: Swift-XRT refined Analysis
  4. GRB 180623A: Enhanced Swift-XRT position
  5. GRB 180623A: Swift detection of a burst
  6. GRB 180620B: Swift/UVOT Detection
  7. GRB 180620A iTelescope observation
  8. Konus-Wind observation of GRB 180620B
  9. Konus-Wind observation of GRB 180620A
  10. GRB 180620B: VLT/X-shooter redshift
  11. Konus-Wind observation of GRB 180618A (a short GRB with extended emission)
  12. GRB 180620B: Swift-BAT refined analysis
  13. GRB 180613A: Afterglow confirmation and added photometry
  14. GROND observations of GRB 180620B
  15. GROND observations of GRB 180620A
  16. GRB 180620B: Swift-XRT refined Analysis
  17. GRB 180618B: CALET Gamma-Ray Burst Monitor detection
  18. GRB 180620A: Swift-BAT refined analysis
  19. GRB 180620B: Enhanced Swift-XRT position
  20. GRB 180620B: Fermi GBM detection
  21. GRB 180620A: KAIT Optical Observations
  22. GRB 180620A: Xinglong-2.16m optical observations
  23. GRB 180618A: Swift/UVOT Detection
  24. GRB 180618A: TSHAO optical upper limit
  25. GRB 180620A: Swift-XRT refined Analysis
  26. GRB 180620B: Swift detection of a burst with an optical counterpart
  27. GRB 180620A: COATLI Detection and Light Curve
  28. GRB 180620A: Swift/UVOT Detection
  29. GRB 180618A: Xinglong-2.16m optical upper limit
  30. GRB 180620A: LCO McDonald observations
  31. GRB 180620A: Enhanced Swift-XRT position
  32. GRB 180620A: MASTER OT observation
  33. GRB 180620A: ISON-MN afterglow confirmation
  34. GRB 180620A: RATIR Optical Afterglow Detection
  35. GRB 180620A: Swift detection of a burst with an optical counterpart
  36. GRB 180618A: MASTER OT observation (a short GRB with extended emission)
  37. GRB 180618A: Swift-BAT refined analysis (a short GRB with extended emission)
  38. GRB 180611A: AstroSat CZTI detection
  39. GRB 180618A: Fermi GBM detection
  40. GRB 180618A: Swift-XRT refined Analysis
  41. GRB 180618A: LT prompt observations
  42. GRB 180618A: Enhanced Swift-XRT position
  43. GRB 180618A: Swift detection of a burst with an optical counterpart
  44. GRB 180614A: AbAO optical observations
  45. GRB 180614A: 1.5m OSN I-band observation
  46. GRB 180614A: Swift/UVOT Upper Limits
  47. GRB 180614A: Swift-BAT refined analysis
  48. GRB 180529A: AstroSat CZTI detection
  49. GRB 180614A: NOT optical upper limits
  50. GRB 180614A: MASTER observation
  51. GRB 180614A: Swift-XRT refined Analysis
  52. GRB 180614A: Enhanced Swift-XRT position
  53. GRB 180614A: Swift detection of a burst
  54. GRB 180613A: Swift/UVOT Upper Limits
  55. GRB 180613A GROND observations: correction
  56. GRB 180613A GROND observations
  57. GRB 180613A, Swift-BAT refined analysis
  58. GRB 180613A: Possible IR afterglow
  59. GRB 180613A: Swift-XRT refined Analysis
  60. GRB 180613A: Enhanced Swift-XRT position
  61. GRB 180613A: Possible host galaxy at XRT position, or star
  62. GRB 180613A: Prompt enhanced Swift-XRT position
  63. Konus-Wind observation of GRB 180611A
  64. GRB 180613A: Swift detection of a burst
  65. GRB 180611A: Fermi GBM observation
  66. IPN Triangulation of GRB 180611A (long)
  67. GRB 180605A: Fermi GBM observation
  68. GRB 180605A: AstroSat CZTI detection
  69. IPN Triangulation of GRB 180605A (long)
  70. GW170817/GRB170817A: LBT optical detection
  71. GRB 180603A: AstroSat CZTI detection
  72. Fermi GBM trigger 180604900/549840956 likely not a GRB
  73. GRB 180602A: MITSuME Ishigakijima optical upper limits
  74. GRB 180602B: Fermi GBM detection
  75. GRB 180602A: Swift/UVOT Upper Limits
  76. GRB 180602A: MITSuME Akeno optical upper limits
  77. GRB 180602A: Swift-XRT refined Analysis
  78. GRB 180602A: Swift-BAT refined analysis
  79. GRB 180602A: MITSuME Okayama optical upper limits
  80. GRB 180602A: Enhanced Swift-XRT position
  81. GRB 180602A: Swift detection of a burst
  82. Fermi GBM trigger 549533811/180601345 is not a GRB
  83. Konus-Wind observation of GRB 180529A
  84. GRB 180529A: CALET Gamma-Ray Burst Monitor detection
  85. IPN Triangulation of GRB 180529A (short/hard)
  86. Swift Trigger 834937 is not a GRB
  87. Konus-Wind observation of GRB 180526A
  88. IPN Triangulation of GRB 180526A (long)
  89. GRB 180526A: CALET Gamma-Ray Burst Monitor detection
  90. Konus-Wind observation of GRB 180523A
  91. GRB 180526A: AstroSat CZTI detection
  92. AGILE/MCAL detection of GRB 180529 and a possible precursor
  93. IPN Triangulation of GRB 180523A
  94. GRB180523B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 548793993)
  95. GRB 180523A: CALET Gamma-Ray Burst Monitor detection
  96. Fermi GBM trigger 548829437/180524192 is not a GRB
  97. GRB 180514A: MITSuME Ishigakijima optical upper limits
  98. GRB 180514A: CrAO/ZTSH optical observations and afterglow candidate
  99. GRB 180505A: AstroSat CZTI detection
  100. GRB 180514A: Swift/UVOT Upper Limits

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