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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 120923A: MITSuME Okayama Optical upper limits
  2. GRB 120916A Suzaku WAM observation of the prompt emission
  3. GRB 120923A: RAPTOR Limits During Gamma-Ray Emitting Interval
  4. GRB 120923A: CARMA Observations
  5. GRB 120923A: EVLA Observations
  6. GRB 120923A: Swift-XRT refined Analysis
  7. GRB 120923A: GROND Upper limits
  8. GRB 120922A: GROND photometric redshift
  9. GRB 120922A: Fermi GBM detection
  10. GRB 120922A: Swift/UVOT Detection
  11. GRB 120923A: Swift-BAT refined analysis
  12. GRB 120922A: Swift-BAT refined analysis
  13. GRB 120923A: Swift/UVOT Upper Limit
  14. GRB 120922A: Swift-XRT refined Analysis
  15. GRB 120922A: Swift/UVOT Observations
  16. GRB 120923A: Gemini afterglow detection, high-z candidate
  17. GRB 120923A: Enhanced Swift-XRT position
  18. GRB 120922A: Enhanced Swift-XRT position
  19. GRB 120922A: TAROT La Silla observatory optical observations
  20. GRB 120923A: TAROT La Silla observatory optical observations
  21. GRB 120923A: ROTSE-III Optical Limits
  22. GRB 120923A: Swift detection of a burst
  23. GRB 120922A: GROND afterglow candidate
  24. GRB 120922A: Prompt enhanced Swift-XRT position
  25. GRB 120922A: Swift detection of a burst
  26. GRB 120919B: MASTER prompt optical observations
  27. GRB 120919A: Swift/UVOT Upper Limits
  28. GRB 120919A: Swift-XRT observations
  29. Konus-Wind observation of GRB 120919B
  30. IPN Triangulation of long GRB 120919B
  31. Konus-Wind observation of GRB 120919A
  32. IPN Triangulation of long GRB 120919A
  33. GRB 120919A: Fermi GBM detection
  34. GRB 120918A: Swift-BAT refined analysis
  35. Swift trigger 534017 was not an astrophysical event
  36. GRB 120916A: Fermi GBM Observation
  37. Konus-Wind observation of GRB 120916A
  38. Swift Trigger 534017 is probably not real.
  39. GRB 120918A: Swift detection of a burst
  40. IPN Triangulation of long GRB 120916A
  41. GRB 120916A: Fermi-LAT detection of a burst
  42. Corrections to the Fermi-LAT upper limits for GRB 120807A, 120908A, 120909A, and 120911A
  43. Swift Transient Swift J174510.8-262411: Swift-BAT refined analysis
  44. Swift Trigger 533836 is a new Galactic transient
  45. GRB 120913B: Fermi GBM observation
  46. GRB 120913B: Swift-BAT refined analysis
  47. GRB 120913A: Fermi GBM observation
  48. GRB 120913B: FRAM early follow up and detection
  49. GRB 120913A: Swift-BAT refined analysis
  50. GRB 120913B: REM NIR early time detection
  51. Continued Skynet/PROMPT observations of GRB120913B
  52. GRB 120913B: TAROT La Silla observatory optical photometry
  53. GRB 120913B: TAROT La Silla observatory optical detection
  54. Skynet/PROMPT observations of GRB120913B
  55. GRB 120913B: Swift detection of a burst
  56. GRB 120913A: Swift detection of a burst
  57. GRB 120907A: optical observations of ISON-Kislovodsk
  58. GRB 120911A: optical upper limit CrAO
  59. GRB 120911A: optical upper limit ISON-NM
  60. Konus-Wind observation of GRB 120911B
  61. GRB 120911B: Fermi GBM observation
  62. GRB 120911B: Fermi-LAT detection of a burst
  63. IPN Triangulation of GRB 120911B (long/bright)
  64. GRB 120911A: Fermi GBM observation
  65. GRB120911A: MITSuME Okayama Optical upper limits
  66. GRB 120911A: Fermi/LAT upper limit
  67. GRB 120911A: Swift/UVOT Upper Limits
  68. GRB 120911A: Swift-XRT refined Analysis
  69. GRB 120911A: Swift-BAT refined analysis
  70. GRB 120911A: Enhanced Swift-XRT position
  71. GRB 120911A: Faulkes Telescope North observations
  72. GRB 120911A: Swift-XRT observations
  73. GRB 120911A: ROTSE-III Optical Limits
  74. GRB 120911A: Swift detection of a burst
  75. GRB 120907A: SMA upper limits
  76. GRB 120908A and GRB 120909A : Fermi/LAT upper limit
  77. GRB 120908A: Fermi GBM detection
  78. GRB 120908A: Swift Observations
  79. GRB 120909A: TAROT La Silla observatory optical observations
  80. GRB 120909A: Pi of the Sky upper limits
  81. GRB 120909A: Fermi GBM observation
  82. Konus-Wind observation of GRB 120909A
  83. GRB 120909A: Swift/UVOT Detection
  84. GRB 120909A: Swift-XRT refined Analysis
  85. GRB 120909A: Swift-BAT refined analysis
  86. GRB 120909A: Enhanced Swift-XRT position
  87. GRB 120908A: MAXI/GSC detection
  88. GRB 120909A: X-Shooter redshift 3.93
  89. GRB 120909A: GROND detection of the afterglow
  90. Skynet/PROMPT Observations of GRB120909A
  91. GRB 120909A: Swift detection of a burst
  92. GRB 120907A: EVLA observations
  93. GRB 120907A: Swift/UVOT Detection
  94. GRB 120907A: Swift-XRT refined Analysis
  95. GRB 120907A: Spectroscopy from OSIRIS/GTC
  96. GRB 120907A: Enhanced Swift-XRT position
  97. GRB 120907A: Fermi GBM detection
  98. GRB 120907A: Swift-BAT refined analysis
  99. GRB 120907A: NOT optical observations
  100. GRB 120907A MASTER optical observations

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