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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 180620A: Swift-XRT refined Analysis
  2. GRB 180620B: Swift detection of a burst with an optical counterpart
  3. GRB 180620A: COATLI Detection and Light Curve
  4. GRB 180620A: Swift/UVOT Detection
  5. GRB 180618A: Xinglong-2.16m optical upper limit
  6. GRB 180620A: LCO McDonald observations
  7. GRB 180620A: Enhanced Swift-XRT position
  8. GRB 180620A: MASTER OT observation
  9. GRB 180620A: ISON-MN afterglow confirmation
  10. GRB 180620A: RATIR Optical Afterglow Detection
  11. GRB 180620A: Swift detection of a burst with an optical counterpart
  12. GRB 180618A: MASTER OT observation (a short GRB with extended emission)
  13. GRB 180618A: Swift-BAT refined analysis (a short GRB with extended emission)
  14. GRB 180611A: AstroSat CZTI detection
  15. GRB 180618A: Fermi GBM detection
  16. GRB 180618A: Swift-XRT refined Analysis
  17. GRB 180618A: LT prompt observations
  18. GRB 180618A: Enhanced Swift-XRT position
  19. GRB 180618A: Swift detection of a burst with an optical counterpart
  20. GRB 180614A: AbAO optical observations
  21. GRB 180614A: 1.5m OSN I-band observation
  22. GRB 180614A: Swift/UVOT Upper Limits
  23. GRB 180614A: Swift-BAT refined analysis
  24. GRB 180529A: AstroSat CZTI detection
  25. GRB 180614A: NOT optical upper limits
  26. GRB 180614A: MASTER observation
  27. GRB 180614A: Swift-XRT refined Analysis
  28. GRB 180614A: Enhanced Swift-XRT position
  29. GRB 180614A: Swift detection of a burst
  30. GRB 180613A: Swift/UVOT Upper Limits
  31. GRB 180613A GROND observations: correction
  32. GRB 180613A GROND observations
  33. GRB 180613A, Swift-BAT refined analysis
  34. GRB 180613A: Possible IR afterglow
  35. GRB 180613A: Swift-XRT refined Analysis
  36. GRB 180613A: Enhanced Swift-XRT position
  37. GRB 180613A: Possible host galaxy at XRT position, or star
  38. GRB 180613A: Prompt enhanced Swift-XRT position
  39. Konus-Wind observation of GRB 180611A
  40. GRB 180613A: Swift detection of a burst
  41. GRB 180611A: Fermi GBM observation
  42. IPN Triangulation of GRB 180611A (long)
  43. GRB 180605A: Fermi GBM observation
  44. GRB 180605A: AstroSat CZTI detection
  45. IPN Triangulation of GRB 180605A (long)
  46. GW170817/GRB170817A: LBT optical detection
  47. GRB 180603A: AstroSat CZTI detection
  48. Fermi GBM trigger 180604900/549840956 likely not a GRB
  49. GRB 180602A: MITSuME Ishigakijima optical upper limits
  50. GRB 180602B: Fermi GBM detection
  51. GRB 180602A: Swift/UVOT Upper Limits
  52. GRB 180602A: MITSuME Akeno optical upper limits
  53. GRB 180602A: Swift-XRT refined Analysis
  54. GRB 180602A: Swift-BAT refined analysis
  55. GRB 180602A: MITSuME Okayama optical upper limits
  56. GRB 180602A: Enhanced Swift-XRT position
  57. GRB 180602A: Swift detection of a burst
  58. Fermi GBM trigger 549533811/180601345 is not a GRB
  59. Konus-Wind observation of GRB 180529A
  60. GRB 180529A: CALET Gamma-Ray Burst Monitor detection
  61. IPN Triangulation of GRB 180529A (short/hard)
  62. Swift Trigger 834937 is not a GRB
  63. Konus-Wind observation of GRB 180526A
  64. IPN Triangulation of GRB 180526A (long)
  65. GRB 180526A: CALET Gamma-Ray Burst Monitor detection
  66. Konus-Wind observation of GRB 180523A
  67. GRB 180526A: AstroSat CZTI detection
  68. AGILE/MCAL detection of GRB 180529 and a possible precursor
  69. IPN Triangulation of GRB 180523A
  70. GRB180523B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 548793993)
  71. GRB 180523A: CALET Gamma-Ray Burst Monitor detection
  72. Fermi GBM trigger 548829437/180524192 is not a GRB
  73. GRB 180514A: MITSuME Ishigakijima optical upper limits
  74. GRB 180514A: CrAO/ZTSH optical observations and afterglow candidate
  75. GRB 180505A: AstroSat CZTI detection
  76. GRB 180514A: Swift/UVOT Upper Limits
  77. GRB 180514A: MITSuME Akeno optical upper limits
  78. GRB 180514A: Detection limits from 2.5m NOT
  79. GRB 180510A: MITSuME Ishigakijima optical upper limits
  80. GRB 180514A: 1.5m OSN optical observations
  81. GRB 180514A: GOTO Optical Observations
  82. GRB 180514A: Swift-BAT refined analysis
  83. GRB 180514A: Swift-XRT refined Analysis
  84. GRB 180514A: Enhanced Swift-XRT position
  85. GRB 180512A: VLT/HAWK-I NIR Observations
  86. GRB 180514A: Swift detection of a burst
  87. Konus-Wind observation of GRB 180510A
  88. GRB 180512A: Swift-XRT refined Analysis
  89. GRB 180512A: Swift-BAT refined analysis
  90. GRB 180512A: RATIR Optical Observations
  91. GRB 180512A: LBT optical detection
  92. GRB 180512A: Swift/UVOT Upper Limits
  93. GRB 180512A: LT prompt observations
  94. GRB 180512A: Enhanced Swift-XRT position
  95. GRB 180512A: GROND upper limits
  96. GRB 180512A: NOT upper limits
  97. GRB 180512A: OASDG optical observations
  98. GRB 180512A: Upper limits from OSN
  99. GRB 180512A: Swift detection of a burst
  100. GRB 180510A: Swift/UVOT followup observations

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