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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 121212A: PdBI mm observations
  2. GRB121212A: NOT optical imaging
  3. GRB 121209A: Early CARMA Observations
  4. GRB 121211A: Continued RATIR Optical and NIR Observations, Fading
  5. GRB 121212A: Maidanak optical observations
  6. GRB 121211A: Fermi GBM observation
  7. GRB 121211A: RATIR Optical and NIR Observations
  8. GRB 121212A: RAPTOR Limits During Gamma-Ray Emitting Interval
  9. GRB 121211A: RAPTOR Limits During Gamma-Ray Emitting Interval
  10. GRB 121212A: PAIRITEL NIR Observations
  11. GRB 121212A: Swift-XRT refined Analysis
  12. GRB 121212A: P60 Observations
  13. GRB 121212A: optical observations in ISON-NM observatory
  14. GRB 121212A: Keck observations
  15. GRB121212A: Swift/UVOT Detection
  16. GRB 121212A: Swift-BAT refined analysis
  17. GRB 121211A: Swift-BAT refined analysis
  18. GRB 121212A: Enhanced Swift-XRT position
  19. GRB 121212A: A long GRB detected by INTEGRAL
  20. GRB 121212A: Swift detection of a burst
  21. GRB 121211A: Swift/UVOT Detection
  22. GRB 121211A: MITSuME Okayama Optical Observation
  23. GRB 121211A: Swift-XRT refined Analysis
  24. GRB 121211A: Enhanced Swift-XRT position
  25. GRB 121211A: Keck/LRIS redshift
  26. GRB 121211A - Faulkes Telescope North afterglow confirmation
  27. GRB 121211A: Swift detection of a burst with an optical counterpart
  28. GRB 121209A: Keck observations
  29. GRB 121209A: CARMA 3mm Observations
  30. GRB 121209A: EVLA Observations
  31. GRB 121209A: Swift-XRT refined Analysis
  32. GRB 121209A: Swift-BAT refined analysis
  33. GRB 121209A: Enhanced Swift-XRT position
  34. GRB121209A: RATIR Optical and NIR Upper Limits
  35. GRB 121209A: GROND optical afterglow candidate
  36. GRB 121209A: Gemini-South imaging
  37. GRB 121209A: PAIRITEL NIR Observations
  38. GRB 121209A: UVOT Observation
  39. GRB 121209A: Swift detection of a burst
  40. GRB 121127A: Suzaku WAM observation of the prompt emission
  41. GRB 121128A: Optical Observations
  42. GRB 121122A: Suzaku WAM observation of the prompt emission
  43. GRB 121202A: Swift/UVOT Upper Limits
  44. GRB 121202A: Swift-XRT refined Analysis
  45. GRB 121202A: Fermi GBM observation
  46. GRB 121202A: Enhanced Swift-XRT position
  47. GRB 121202A: Swift-BAT refined analysis
  48. GRB 121202A: Swift-XRT observations
  49. GRB 121201A: X-shooter redshift
  50. GRB121202A: Swift/UVOT Observations
  51. GRB 121202A: TAROT Calern observatory optical observations
  52. GRB 121202A: Swift detection of a burst
  53. GRB 121201A: GROND afterglow observations and photometric redshift
  54. GRB 121201A: Swift/UVOT Detection
  55. GRB 121201A: Swift-XRT refined Analysis
  56. GRB 121201A: Swift-BAT refined analysis
  57. GRB 121201A: Enhanced Swift-XRT position
  58. GRB 121201A: BOOTES-4 optical observations
  59. GRB 121201A: a GRB with an optical counterpart
  60. GRB 121128A: optical observation in Mondy observatory
  61. GRB 121128A: MITSuME Akeno Optical upper limits
  62. Konus-Wind observation of GRB 121127A
  63. IPN Triangulation of GRB 121127A (short/hard)
  64. GRB 121125A: optical upper limit
  65. GRB 121128A: optical observation in Mondy observatory
  66. GRB 121128A: WSRT radio observation
  67. GRB 121128A: Swift/UVOT Detection
  68. GRB 121128A: Swift-XRT refined Analysis
  69. GRB 121128A: Enhanced Swift-XRT position
  70. GRB 121122A: Fermi GBM observation
  71. GRB 121128A: RAPTOR Detection During Gamma-Ray Emitting Interval
  72. GRB 121128A: Fermi GBM observation
  73. GRB 121128A, Swift-BAT refined analysis
  74. Konus-Wind observation of GRB 121128A
  75. GRB 121128A - Gemini North redshift
  76. GRB 121128A: FTN optical afterglow confirmation
  77. GRB 121128A: Swift detection of a burst with an optical counterpart
  78. GRB 121123A: Suzaku WAM observation of the prompt emission
  79. Konus-Wind observation of GRB 121122A
  80. GRB 121117A: Terskol obseravtions
  81. GRB 121123A: Swift/UVOT Observations
  82. GRB 121125A: Swift/UVOT Detection
  83. IPN Triangulation of GRB 121122A (long/intense)
  84. GRB 121118B: Suzaku WAM observation of the prompt emission
  85. GRB 121125A: Swift-XRT refined Analysis
  86. GRB 121125A: Enhanced Swift-XRT position
  87. GRB 121125A: Fermi GBM Observation
  88. GRB 121125A: Swift-BAT refined analysis
  89. GRB 121125A: LOAO Observation
  90. GRB 121125A: MASTER-NET optical observations
  91. GRB 121125A: Swift detection of a burst with optical counterpart
  92. GRB 121123A: GROND observations
  93. GRB 121123A: Enhanced Swift-XRT position
  94. GRB 121123A: Swift-BAT refined analysis
  95. GRB 121123A: Swift-XRT refined Analysis
  96. GRB 121123A: optical observations
  97. GRB 121123A: BOOTES-4 and IAC80 optical observations
  98. GRB 121123A: NOT optical observations
  99. GRB 121123A: Fermi GBM observation
  100. GRB 121123A: MASTER-NET optical limit

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