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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 091231: GROND NIR observations
  2. Swift Trigger 381591: Uncatalogued UVOT Source
  3. GRB 091230: Swift/UVOT Observations
  4. Trigger 381591: Swift detection of a possible burst
  5. GRB 091230: Swift-XRT observation
  6. GRB 091230: GROND optical/NIR afterglow candidate
  7. GRB 091230: a long GRB detected by INTEGRAL
  8. Swift Trigger 381434 is not a GRB
  9. Trigger 381434: Swift detection of a possible burst
  10. GRB 091221 : IRSF NIR upper limit
  11. GRB 091221: Skynet/PROMPT Detections
  12. GRB 091221: Fermi GBM Observation
  13. GRB 091117: Swift-XRT late time observations
  14. GRB 091221 Swift-BAT refined analysis
  15. GRB091221: Swift/UVOT refined analysis, correction.
  16. GRB 091221: Swift/UVOT refined analysis
  17. GRB 091221: Swift-XRT refined analysis
  18. GRB 091221: Enhanced Swift-XRT position
  19. GRB 091221, GROND observations
  20. GRB 091221: UVOT Confirmation of an Optical Afterglow
  21. GRB 091221: ROTSE-III Detection of Optical Counterpart
  22. GRB 091221: Swift detection of a burst
  23. Swift trigger 379449 (possible GRB) is not a burst
  24. GRB 091215: Faulkes Telescope North observations
  25. Trigger 379449: Swift detection of a possible burst
  26. GRB 091208B: Xinglong TNT optical observation
  27. GRB 091208A: Suzaku WAM observation of the prompt emission
  28. GRB 091208A: GAO 150cm telescope Optical Observation
  29. Konus-Wind observation of GRB 091208A
  30. GRB 091208B: GAO 150cm telescope Optical Observation
  31. GRB091208A: Swift/UVOT refined analysis
  32. GRB 091208B: optical observations
  33. GRB 091208B: Keck HIRES redshift confirmation
  34. GRB 091208B: GROND observations
  35. GRB 091208A: Swift-XRT observations
  36. GRB091208B: NOT optical observations
  37. GRB 091208B: Swift-XRT refined analysis
  38. GRB091208B: Swift/UVOT refined analysis
  39. GRB 091208B: Fermi GBM observation
  40. GRB 091208B, Swift-BAT refined analysis
  41. GRB 091208A Swift-BAT refined analysis
  42. GRB 091208B: Gemini-North redshift
  43. GRB 091208B: Faulkes Telescope North and South Optical Afterglow
  44. GRB 091208A, RIMOTS optical upper limits
  45. GRB 091208B: MITSuME Akeno Optical Observation
  46. GRB 091208B: Enhanced Swift-XRT position
  47. GRB 091208B: MITSuME Okayama Optical Observation
  48. GRB 091208B, RIMOTS optical upper limits
  49. GRB 091208B: Swift detection of a burst with an optical afterglow
  50. GRB 091208B: BOOTES-3 optical afterglow
  51. GRB 091208: ROTSE-III Optical Limits
  52. GRB 091208: Swift detection of a burst
  53. Short X-ray Transient, RIMOTS optical upper limits
  54. A small revision to the GRB-naming convention
  55. GRB 091123: Suzaku WAM observation of the prompt emission
  56. GRB 091127: Skynet/PROMPT Observations of Possible Host Galaxy
  57. GRB 091127: GAO 150cm telescope Optical Observation
  58. GRB 091202: GTC & CAHA optical/nIR afterglow candidate
  59. GRB 091109A: GROND confirmation of redshift z = 3.5
  60. GRB091127: Continuing Swift/UVOT Observations
  61. GRB 091127, SMARTS optical/IR afterglow observations
  62. GRB091202: Swift-XRT refined analysis
  63. GRB 091202: Swift/UVOT Upper Limits
  64. GRB 091202: Liverpool Telescope observations
  65. GRB 091202: Optical and NIR observations
  66. GRB 091202 - UVOT-enhanced XRT position
  67. GRB 091127: Zadko Telescope Observations
  68. GRB 091126A: Suzaku WAM observation of the prompt emission
  69. GRB 091202: TAROT Calern observatory optical observations
  70. GRB 091202: Liverpool Telescope Observations
  71. GRB 091202: a long GRB detected by INTEGRAL
  72. GRB 091127: redshift confirmation with X-shooter
  73. GRB 091117: Chandra Observations
  74. GRB 091020: MASTER-Net optical polarization observations
  75. GRB 091127: Skynet/PROMPT Continued Observations of Fading
  76. Short X-ray Transient Detection by MAXI/GSC
  77. Konus-Wind observation of very long GRB 091123
  78. GRB 091130A: Xinglong TNT upper limit
  79. GRB 091123: Fermi GBM detection of a very long burst
  80. GRB 091126B: Fermi GBM detection
  81. GRB 091127: Suzaku WAM observation of the prompt emission
  82. GRB 091126: Fermi GBM detection
  83. GRB 091130B: Swift-XRT team refined analysis
  84. GRB 091130B: Swift-BAT refined analysis
  85. GRB 091130B: Swift/UVOT Upper Limits
  86. GRB 091127: Skynet/PROMPT Observations of Fading
  87. GRB 091130B: Enhanced Swift-XRT position
  88. Swift trigger 377436 (possible GRB 091130A) is not a burst
  89. GRB 091130B: MASTER observations
  90. GRB 091130B: SDSS galaxy at XRT location
  91. GRB 091130B: Swift detection of a burst
  92. GRB 091130: MASTER observations
  93. GRB 091130: Swift detection of a possible burst
  94. GRB 091127: Radio observations
  95. GRB 091128: Fermi GBM detection
  96. Konus-Wind observation of GRB 091127
  97. GRB 091127: TAROT La Silla observatory optical observations
  98. GRB 091127: optical observations
  99. GRB 091127: LABOCA/APEX submm observations
  100. GRB 091127: Further NOT optical observations

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