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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 120911A: Swift-BAT refined analysis
  2. GRB 120911A: Enhanced Swift-XRT position
  3. GRB 120911A: Faulkes Telescope North observations
  4. GRB 120911A: Swift-XRT observations
  5. GRB 120911A: ROTSE-III Optical Limits
  6. GRB 120911A: Swift detection of a burst
  7. GRB 120907A: SMA upper limits
  8. GRB 120908A and GRB 120909A : Fermi/LAT upper limit
  9. GRB 120908A: Fermi GBM detection
  10. GRB 120908A: Swift Observations
  11. GRB 120909A: TAROT La Silla observatory optical observations
  12. GRB 120909A: Pi of the Sky upper limits
  13. GRB 120909A: Fermi GBM observation
  14. Konus-Wind observation of GRB 120909A
  15. GRB 120909A: Swift/UVOT Detection
  16. GRB 120909A: Swift-XRT refined Analysis
  17. GRB 120909A: Swift-BAT refined analysis
  18. GRB 120909A: Enhanced Swift-XRT position
  19. GRB 120908A: MAXI/GSC detection
  20. GRB 120909A: X-Shooter redshift 3.93
  21. GRB 120909A: GROND detection of the afterglow
  22. Skynet/PROMPT Observations of GRB120909A
  23. GRB 120909A: Swift detection of a burst
  24. GRB 120907A: EVLA observations
  25. GRB 120907A: Swift/UVOT Detection
  26. GRB 120907A: Swift-XRT refined Analysis
  27. GRB 120907A: Spectroscopy from OSIRIS/GTC
  28. GRB 120907A: Enhanced Swift-XRT position
  29. GRB 120907A: Fermi GBM detection
  30. GRB 120907A: Swift-BAT refined analysis
  31. GRB 120907A: NOT optical observations
  32. GRB 120907A MASTER optical observations
  33. GRB 120907A: ROTSE-III Optical Limits
  34. GRB 120907A: Swift detection of a burst with optical counterpart
  35. XMM observations of the short GRB120804A
  36. GRB 120819A: optical upper limit
  37. GRB 120802A: optical observations in CrAO
  38. GRB 120830A: Further Swift Observations
  39. GRB 120830A: catalog source at Uvot position
  40. GRB 120830A: Swift-XRT and UVOT observations
  41. GRB 120830A: Fermi GBM observation
  42. Konus-Wind observation of GRB 120830A
  43. GRB 120830A: early MASTER optical limit
  44. IPN Triangulation of short GRB 120830A
  45. GRB 120830A: Fermi-LAT detection of a short burst
  46. Fermi trigger 368003226 : MASTER optical observations
  47. GRB 120819A: Swift/UVOT Upper Limits
  48. GRB 120817A: Swift/UVOT Upper Limits
  49. GRB 120817B: Deep limit on the optical afterglow from du Pont and Magellan observations
  50. GRB 120821A: Swift/XRT observations
  51. GRB 120821A: Swift/UVOT Upper Limits
  52. GRB 120821A: GROND upper limits
  53. GRB 120821A: a long GRB detected by INTEGRAL
  54. GRB 120817B - PTF Observations
  55. GRB 120817A: RAPTOR Limits During Gamma-Ray Emitting Interval
  56. GRB 120811C: optical observations
  57. GRB 120817B: BAT location in ground analysis and refined analysis
  58. GRB 120819A: MASTER final limits
  59. GRB 120819A: Bassano Bresciano Observatory optical observations
  60. GRB 120819A: Swift-BAT refined analysis
  61. GRB 120819A: GROND afterglow confirmation
  62. GRB 120819A: Swift-XRT refined Analysis
  63. GRB 120819A: MITSuME Ishigakijima upper limits
  64. GRB 120819A: MITSuME Okayama Optical upper limits
  65. GRB 120819A: Enhanced Swift-XRT position
  66. GRB 120819A: afterglow candidate from NOT
  67. GRB 120819A: MASTER optical observations
  68. GRB 120819A: Swift detection of a burst
  69. GRB 120817B: Swift-XRT observations
  70. GRB 120811C: optical observations
  71. GRB 120816A: Swift/UVOT Detection of the Optical Afterglow
  72. GRB 120815A: MASTER-ICATE observations
  73. Konus-Wind observation of GRB 120816B
  74. IPN Triangulation of GRB 120816B (short/exceptionally intense)
  75. Konus-Wind observation of GRB 120817B
  76. GRB 120817A: Swift-XRT refined Analysis
  77. GRB 120817B: LCO Optical Observations
  78. GRB 120817B: Fermi GBM detection
  79. IPN Triangulation of GRB 120817B (short/very intense)
  80. GRB 120817A: Swift-BAT refined analysis
  81. GRB 120816A: optical upper limit
  82. GRB 120817A: Enhanced Swift-XRT position
  83. GRB 120815A: Swift/UVOT Detection of the Optical Afterglow
  84. GRB 120816A: Bassano Bresciano Observatory optical observations
  85. GRB 120817A: FTN and FTS observations
  86. GRB 120816A: Swift-XRT refined Analysis
  87. GRB 120817A: Swift-XRT observations
  88. GRB 120817A: Swift detection of a burst
  89. GRB 120816A: Enhanced Swift-XRT position
  90. GRB 120816A: Swift-BAT refined analysis
  91. GRB 120816A: BOOTES-2 observations
  92. GRB120816A: OPTIMA discovery of optical counterpart
  93. GRB 120816A: TAROT Calern observatory optical observations
  94. GRB 120816A: ROTSE-III Optical Limits
  95. GRB 120816A: Swift detection of a burst
  96. GRB 120815A: Swift-XRT refined Analysis
  97. GRB 120815A: Swift-BAT refined analysis
  98. GRB 120805A: Liverpool Telescope optical candidate detection
  99. GRB 120815A: Enhanced Swift-XRT position
  100. GRB 120815A: VLT/X-shooter redshift

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