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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"

43658 results found.

  1. GRB 120804A: Late-time Chandra observation
  2. GRB 121001A: GROND Afterglow Confirmation
  3. GRB 121001A: Swift-XRT refined Analysis
  4. GRB 121001A: Enhanced Swift-XRT Position
  5. Swift Trigger 535026 is GRB 121001A: Swift-BAT refined analysis
  6. Swift Trigger 535026: Optical decay confirmation with IAC80 and BOOTES-2/TELMA.
  7. GRB 121001A: MASTER optical observations
  8. GRB 121001A: possible optical counterpart
  9. Swift Trigger 535026: ROTSE-III Optical Limits
  10. Swift Trigger 535026: Galactic Transient or possible GRB
  11. GRB 120927A: Swift/UVOT Upper Limits
  12. GRB 120927A, Swift-BAT refined analysis
  13. GRB 120927A: GROND upper limits
  14. GRB 120927A: Swift-XRT refined Analysis
  15. GRB 120927A: Enhanced Swift-XRT position
  16. GRB 120923A: JHK Observation
  17. GRB 120927A: Swift detection of a burst
  18. Further Swift-XRT observations of the GRB 120919A field.
  19. GRB 120923A: optical upper limit
  20. GRB 120921A: Fermi GBM detection of its 1000th GRB
  21. GRB 120916A Suzaku WAM observation of the prompt emission
  22. GRB 120923A: RAPTOR Limits During Gamma-Ray Emitting Interval
  23. GRB 120923A: CARMA Observations
  24. GRB 120923A: EVLA Observations
  25. GRB 120923A: Swift-XRT refined Analysis
  26. GRB 120923A: GROND Upper limits
  27. GRB 120922A: GROND photometric redshift
  28. GRB 120922A: Fermi GBM detection
  29. GRB 120922A: Swift/UVOT Detection
  30. GRB 120923A: Swift-BAT refined analysis
  31. GRB 120922A: Swift-BAT refined analysis
  32. GRB 120923A: Swift/UVOT Upper Limit
  33. GRB 120922A: Swift-XRT refined Analysis
  34. GRB 120922A: Swift/UVOT Observations
  35. GRB 120923A: Gemini afterglow detection, high-z candidate
  36. GRB 120923A: Enhanced Swift-XRT position
  37. GRB 120922A: Enhanced Swift-XRT position
  38. GRB 120922A: TAROT La Silla observatory optical observations
  39. GRB 120923A: TAROT La Silla observatory optical observations
  40. GRB 120923A: ROTSE-III Optical Limits
  41. GRB 120923A: Swift detection of a burst
  42. GRB 120922A: GROND afterglow candidate
  43. GRB 120922A: Prompt enhanced Swift-XRT position
  44. GRB 120922A: Swift detection of a burst
  45. GRB 120919B: MASTER prompt optical observations
  46. GRB 120919A: Swift/UVOT Upper Limits
  47. GRB 120919A: Swift-XRT observations
  48. Konus-Wind observation of GRB 120919B
  49. IPN Triangulation of long GRB 120919B
  50. Konus-Wind observation of GRB 120919A
  51. IPN Triangulation of long GRB 120919A
  52. GRB 120919A: Fermi GBM detection
  53. GRB 120918A: Swift-BAT refined analysis
  54. GRB 120916A: Fermi GBM Observation
  55. Konus-Wind observation of GRB 120916A
  56. Swift Trigger 534017 is probably not real.
  57. GRB 120918A: Swift detection of a burst
  58. IPN Triangulation of long GRB 120916A
  59. GRB 120916A: Fermi-LAT detection of a burst
  60. Corrections to the Fermi-LAT upper limits for GRB 120807A, 120908A, 120909A, and 120911A
  61. Swift Transient Swift J174510.8-262411: Swift-BAT refined analysis
  62. Swift Trigger 533836 is a new Galactic transient
  63. GRB 120913B: Fermi GBM observation
  64. GRB 120913B: Swift-BAT refined analysis
  65. GRB 120913A: Fermi GBM observation
  66. GRB 120913B: FRAM early follow up and detection
  67. GRB 120913A: Swift-BAT refined analysis
  68. GRB 120913B: REM NIR early time detection
  69. Continued Skynet/PROMPT observations of GRB120913B
  70. GRB 120913B: TAROT La Silla observatory optical photometry
  71. GRB 120913B: TAROT La Silla observatory optical detection
  72. Skynet/PROMPT observations of GRB120913B
  73. GRB 120913B: Swift detection of a burst
  74. GRB 120913A: Swift detection of a burst
  75. GRB 120907A: optical observations of ISON-Kislovodsk
  76. GRB 120911A: optical upper limit CrAO
  77. GRB 120911A: optical upper limit ISON-NM
  78. Konus-Wind observation of GRB 120911B
  79. GRB 120911B: Fermi GBM observation
  80. GRB 120911B: Fermi-LAT detection of a burst
  81. IPN Triangulation of GRB 120911B (long/bright)
  82. GRB 120911A: Fermi GBM observation
  83. GRB 120911A: Fermi/LAT upper limit
  84. GRB 120911A: Swift-XRT refined Analysis
  85. GRB 120911A: Swift-BAT refined analysis
  86. GRB 120911A: Enhanced Swift-XRT position
  87. GRB 120911A: Faulkes Telescope North observations
  88. GRB 120911A: Swift-XRT observations
  89. GRB 120911A: ROTSE-III Optical Limits
  90. GRB 120911A: Swift detection of a burst
  91. GRB 120907A: SMA upper limits
  92. GRB 120908A and GRB 120909A : Fermi/LAT upper limit
  93. GRB 120908A: Fermi GBM detection
  94. GRB 120908A: Swift Observations
  95. GRB 120909A: TAROT La Silla observatory optical observations
  96. GRB 120909A: Pi of the Sky upper limits
  97. GRB 120909A: Fermi GBM observation
  98. Konus-Wind observation of GRB 120909A
  99. GRB 120909A: Swift/UVOT Detection
  100. GRB 120909A: Swift-XRT refined Analysis

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