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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"

21772 results found.

  1. GRB 091208A: Swift-XRT observations
  2. GRB091208B: NOT optical observations
  3. GRB 091208A, RIMOTS optical upper limits
  4. GRB 091208B: MITSuME Akeno Optical Observation
  5. GRB 091208B: Enhanced Swift-XRT position
  6. GRB 091208B: MITSuME Okayama Optical Observation
  7. GRB 091208B, RIMOTS optical upper limits
  8. GRB 091208B: Swift detection of a burst with an optical afterglow
  9. GRB 091208B: BOOTES-3 optical afterglow
  10. GRB 091208: ROTSE-III Optical Limits
  11. GRB 091123: Suzaku WAM observation of the prompt emission
  12. GRB 091127: GAO 150cm telescope Optical Observation
  13. GRB 091202: GTC & CAHA optical/nIR afterglow candidate
  14. GRB 091109A: GROND confirmation of redshift z = 3.5
  15. GRB 091127, SMARTS optical/IR afterglow observations
  16. GRB 091202: Swift/UVOT Upper Limits
  17. GRB 091202 - UVOT-enhanced XRT position
  18. GRB 091127: Zadko Telescope Observations
  19. GRB 091126A: Suzaku WAM observation of the prompt emission
  20. GRB 091202: TAROT Calern observatory optical observations
  21. GRB 091117: Chandra Observations
  22. Konus-Wind observation of very long GRB 091123
  23. GRB 091123: Fermi GBM detection of a very long burst
  24. GRB 091127: Suzaku WAM observation of the prompt emission
  25. GRB 091130B: Swift/UVOT Upper Limits
  26. GRB 091130B: Enhanced Swift-XRT position
  27. Swift trigger 377436 (possible GRB 091130A) is not a burst
  28. GRB 091130B: Swift detection of a burst
  29. GRB 091127: Radio observations
  30. Konus-Wind observation of GRB 091127
  31. GRB 091127: TAROT La Silla observatory optical observations
  32. GRB 091127: LABOCA/APEX submm observations
  33. GRB 091127: Further NOT optical observations
  34. GRB 091127: Swift-XRT afterglow detection and analysis
  35. GRB 091127: TAROT La Silla observatory optical decay
  36. GRB 091127: Swift/UVOT observations
  37. GRB 091127: NOT observations
  38. GRB 091127 : GROND observations
  39. GRB 091127: REM NIR afterglow detection
  40. Konus-Wind observation of GRB 091120
  41. GRB 091120: Fermi GBM observation
  42. GRB 091117A: Suzaku WAM observation of the prompt emission
  43. GRB 091117: TNG optical observations
  44. GRB 091117A: Swift/UVOT followup observations
  45. GRB 091117: Evidence for Variability of XRT Source #1
  46. GRB091117: Gemini South Observations
  47. GRB 091117: Swift XRT refined analysis
  48. Konus-Wind observations of GRB 091117A
  49. GRB 091112: Suzaku WAM observation of the prompt emission
  50. GRB 091102A: Suzaku WAM observation of the prompt emission
  51. GRB 091109B: Suzaku WAM observation of the prompt emission
  52. GRB091111: Swift XRT refined analysis
  53. Konus-Wind and Konus-RF observations of GRB 091031
  54. GRB 091031: Fermi LAT detection of a faint burst
  55. GRB 091112: Swift detection of a possible burst
  56. GRB 091111: BOOTES-3 contemporaneous imaging
  57. GRB 091111: BOOTES-3 observations
  58. GRB 091109A: GROND and VLT observations
  59. GRB 091109B: Swift/UVOT Upper Limits
  60. GRB 091109B: Enhanced Swift-XRT position
  61. GRB 091109B: Optical limits from Watcher
  62. GRB 091109B: ROTSE-III Optical Limits
  63. GRB 091109B: Swift detection of a short burst
  64. GRB 091030: Fermi GBM detection
  65. GRB 091109: BOOTES-3 observations
  66. GRB 091109: Swift/UVOT observations
  67. GRB 091109: Enhanced Swift-XRT position
  68. GRB091109: REM detection of the NIR afterglow
  69. GRB 091109: Swift detection of a burst with optical afterglow
  70. GRB 091029: Observations from Stardome Observatory
  71. GRB 091104: Swift/UVOT Upper Limits
  72. GRB091026 : IRSF NIR upper limit
  73. GRB091102 : MOA optical upper limit
  74. GRB 091104: Enhanced Swift-XRT position
  75. GRB 091104: Swift detection of a burst
  76. GRB 091102: LABOCA/APEX submm observations
  77. Fermi LAT Upper Limits on GRB 091010
  78. GRB 091102 : Faulkes Telescope South Upper Limits
  79. GRB 091102: Swift/UVOT Upper Limits
  80. GRB 091102: GROND Upper Limits
  81. GRB 091102: BOOTES-3 observations
  82. GRB 091102: Swift/XRT localization
  83. GRB 091102: ROTSE-III Optical Limits
  84. GRB 091024: optical observations
  85. GRB 091024: Fermi LAT upper limits
  86. GRB 091018, SMARTS optical/IR afterglow observations
  87. GRB091029: Swift/UVOT observations
  88. GRB 091029: Skynet/PROMPT Continued Observations of Fading
  89. GRB 091029: Swift-BAT refined analysis
  90. GRB 091029: Enhanced Swift-XRT position
  91. GRB091024 optical observations
  92. GRB 091029: Skynet/PROMPT Observations of Peak and Fading
  93. GRB 091029: GROND Detection of the Optical/NIR Afterglow
  94. GRB 091029: Swift detection of a burst with an optical counterpart
  95. GRB 091026: Suzaku WAM observation of the prompt emission
  96. GRB 091026: GROND Upper Limits
  97. GRB 091026: Swift-BAT refined analysis
  98. Radio afterglow detection from GRB 091020
  99. GRB 091026: Swift/UVOT Upper Limits
  100. GRB 091024: Burst was outside the Swift-BAT FOV after T0(BAT)+460sec

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