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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 121017A: Enhanced Swift-XRT position
  2. GRB 121017A: 1.23m CAHA R-band observations
  3. GRB 121017A optical observations
  4. GRB 121017A: BOOTES-2/TELMA observations
  5. GRB 121017A: Swift detection of a burst
  6. GRB 121011B: Suzaku WAM observation of the prompt emission
  7. GRB 121011A Suzaku WAM observation of the prompt emission
  8. GRB 121012A: Fermi GBM detection
  9. PdB IRAM observation of GRB 121011A
  10. Konus-Wind observation of GRB 121011B
  11. GRB 121014A: Swift-BAT refined analysis
  12. GRB 121011A: WSRT radio observation
  13. GRB 121014A: Swift detection of a burst
  14. INTEGRAL Alert n.6678: NOT A GRB
  15. GRB 121011A: optical observations
  16. GRB 121011A: Swift/UVOT Detection
  17. IPN Triangulation of short hard GRB 121011B
  18. GRB 121011A: NOT redshift retraction
  19. GRB 121011A: misprint in GCNC 13854
  20. GRB 121011A: Fermi GBM observation
  21. GRB 121011A: Fermi-LAT detection of a burst
  22. Swift-BAT trigger 535733 is not astrophysical
  23. GRB 121011A: Swift-XRT refined Analysis
  24. GRB 121011A: NOT optical observations
  25. GRB 121011A: optical observations
  26. GRB 121011A: MASTER-Net bell light curve
  27. GRB 121011A: TNG optical observations
  28. GRB 121011A, Swift-BAT refined analysis
  29. Swift-BAT refined analysis of the SGR 1806-20 outburst (trigger 535747)
  30. GRB 121011A: Enhanced Swift-XRT position
  31. Planned XMM-Newton and IRAM observation of GRB 121011A
  32. GRB 121011A: MASTER-Net early OT light curve
  33. GRB121011A : Xinglong TNT optical observation
  34. GRB 121011A: MITSuME Okayama Optical Observation
  35. GRB 121011A: Swift detection of a burst with optical afterglow
  36. Trigger 535747: Swift detection of an outburst from SGR1806-20
  37. Trigger 535733: Swift possible detection of SAX J1828.5-1037
  38. GRB 120927A: optical upper limit
  39. GRB 120804A: Late-time Chandra observation
  40. GRB 121001A: GROND Afterglow Confirmation
  41. GRB 121001A: Swift/UVOT Upper Limits
  42. GRB 121001A: Swift-XRT refined Analysis
  43. GRB 121001A: Enhanced Swift-XRT Position
  44. Swift Trigger 535026 is GRB 121001A: Swift-BAT refined analysis
  45. Swift Trigger 535026: Optical decay confirmation with IAC80 and BOOTES-2/TELMA.
  46. GRB 121001A: MASTER optical observations
  47. GRB 121001A: possible optical counterpart
  48. Swift Trigger 535026: ROTSE-III Optical Limits
  49. Swift Trigger 535026: Galactic Transient or possible GRB
  50. GRB 120927A: Swift/UVOT Upper Limits
  51. GRB 120927A, Swift-BAT refined analysis
  52. GRB 120927A: GROND upper limits
  53. GRB 120927A: Swift-XRT refined Analysis
  54. GRB 120923A: Correction to GCN 13823
  55. GRB 120927A: Enhanced Swift-XRT position
  56. GRB 120923A: JHK Observation
  57. GRB 120927A: Swift detection of a burst
  58. Further Swift-XRT observations of the GRB 120919A field.
  59. GRB 120923A: optical upper limit
  60. GRB 120921A: Fermi GBM detection of its 1000th GRB
  61. GRB 120923A: RAPTOR Early Afterglow Limits
  62. GRB 120923A: MITSuME Okayama Optical upper limits
  63. GRB 120916A Suzaku WAM observation of the prompt emission
  64. GRB 120923A: RAPTOR Limits During Gamma-Ray Emitting Interval
  65. GRB 120923A: CARMA Observations
  66. GRB 120923A: EVLA Observations
  67. GRB 120923A: Swift-XRT refined Analysis
  68. GRB 120923A: GROND Upper limits
  69. GRB 120922A: GROND photometric redshift
  70. GRB 120922A: Fermi GBM detection
  71. GRB 120922A: Swift/UVOT Detection
  72. GRB 120923A: Swift-BAT refined analysis
  73. GRB 120922A: Swift-BAT refined analysis
  74. GRB 120923A: Swift/UVOT Upper Limit
  75. GRB 120922A: Swift-XRT refined Analysis
  76. GRB 120922A: Swift/UVOT Observations
  77. GRB 120923A: Gemini afterglow detection, high-z candidate
  78. GRB 120923A: Enhanced Swift-XRT position
  79. GRB 120922A: Enhanced Swift-XRT position
  80. GRB 120922A: TAROT La Silla observatory optical observations
  81. GRB 120923A: TAROT La Silla observatory optical observations
  82. GRB 120923A: ROTSE-III Optical Limits
  83. GRB 120923A: Swift detection of a burst
  84. GRB 120922A: GROND afterglow candidate
  85. GRB 120922A: Prompt enhanced Swift-XRT position
  86. GRB 120922A: Swift detection of a burst
  87. GRB 120919B: MASTER prompt optical observations
  88. GRB 120919A: Swift/UVOT Upper Limits
  89. GRB 120919A: Swift-XRT observations
  90. Konus-Wind observation of GRB 120919B
  91. IPN Triangulation of long GRB 120919B
  92. Konus-Wind observation of GRB 120919A
  93. IPN Triangulation of long GRB 120919A
  94. GRB 120919A: Fermi GBM detection
  95. GRB 120918A: Swift-BAT refined analysis
  96. Swift trigger 534017 was not an astrophysical event
  97. GRB 120916A: Fermi GBM Observation
  98. Konus-Wind observation of GRB 120916A
  99. Swift Trigger 534017 is probably not real.
  100. GRB 120918A: Swift detection of a burst

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