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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"

20366 results found.

  1. GRB 091221: Enhanced Swift-XRT position
  2. GRB 091221: UVOT Confirmation of an Optical Afterglow
  3. GRB 091221: Swift detection of a burst
  4. Swift trigger 379449 (possible GRB) is not a burst
  5. GRB 091215: Faulkes Telescope North observations
  6. Trigger 379449: Swift detection of a possible burst
  7. GRB 091208A: GAO 150cm telescope Optical Observation
  8. GRB091208A: Swift/UVOT refined analysis
  9. GRB 091208B: optical observations
  10. GRB 091208B: GROND observations
  11. GRB 091208A: Swift-XRT observations
  12. GRB091208B: NOT optical observations
  13. GRB 091208A, RIMOTS optical upper limits
  14. GRB 091208B: MITSuME Akeno Optical Observation
  15. GRB 091208B: Enhanced Swift-XRT position
  16. GRB 091208B: MITSuME Okayama Optical Observation
  17. GRB 091208B, RIMOTS optical upper limits
  18. GRB 091208B: Swift detection of a burst with an optical afterglow
  19. GRB 091208B: BOOTES-3 optical afterglow
  20. GRB 091202: GTC & CAHA optical/nIR afterglow candidate
  21. GRB 091109A: GROND confirmation of redshift z = 3.5
  22. GRB 091127, SMARTS optical/IR afterglow observations
  23. GRB 091202: Swift/UVOT Upper Limits
  24. GRB 091202 - UVOT-enhanced XRT position
  25. GRB 091127: Zadko Telescope Observations
  26. GRB 091202: TAROT Calern observatory optical observations
  27. GRB 091117: Chandra Observations
  28. GRB 091020: MASTER-Net optical polarization observations
  29. GRB 091123: Fermi GBM detection of a very long burst
  30. GRB 091130B: Swift/UVOT Upper Limits
  31. GRB 091127: Skynet/PROMPT Observations of Fading
  32. GRB 091130B: Enhanced Swift-XRT position
  33. GRB 091130B: Swift detection of a burst
  34. GRB 091127: Radio observations
  35. Konus-Wind observation of GRB 091127
  36. GRB 091127: TAROT La Silla observatory optical observations
  37. GRB 091127: LABOCA/APEX submm observations
  38. GRB 091127: Further NOT optical observations
  39. GRB 091127: MASTER early optical transient polarimetry
  40. GRB 091127: Swift-XRT afterglow detection and analysis
  41. GRB 091127: TAROT La Silla observatory optical decay
  42. GRB 091127: Swift/UVOT observations
  43. GRB 091127: Swift-BAT refined analysis
  44. GRB 091127: NOT observations
  45. GRB 091127 : GROND observations
  46. GRB 091127: REM NIR afterglow detection
  47. GRB 091120: Fermi GBM observation
  48. GRB 091117: TNG optical observations
  49. GRB 091117A: Swift/UVOT followup observations
  50. GRB 091117: Evidence for Variability of XRT Source #1
  51. GRB091117: Gemini South Observations
  52. GRB 091117: Swift XRT refined analysis
  53. GRB091111: Swift XRT refined analysis
  54. GRB 091112: Swift-BAT refined analysis
  55. GRB 091031: Fermi LAT detection of a faint 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 091109: BOOTES-3 observations
  65. GRB 091109: Swift/UVOT observations
  66. GRB 091109: Enhanced Swift-XRT position
  67. GRB091109: REM detection of the NIR afterglow
  68. GRB 091109: Swift detection of a burst with optical afterglow
  69. GRB 091029: Observations from Stardome Observatory
  70. GRB 091104: Swift XRT Refined Analysis
  71. GRB 091104: Swift/UVOT Upper Limits
  72. GRB 091104: Enhanced Swift-XRT position
  73. GRB 091104: Swift detection of a burst
  74. GRB 091102: LABOCA/APEX submm observations
  75. Fermi LAT Upper Limits on GRB 091010
  76. GRB 091102 : Faulkes Telescope South Upper Limits
  77. GRB 091102: Swift/UVOT Upper Limits
  78. GRB 091102: GROND Upper Limits
  79. GRB 091102: BOOTES-3 observations
  80. GRB 091102: Swift/XRT localization
  81. GRB 091024: optical observations
  82. GRB 091024: Fermi LAT upper limits
  83. GRB 091018, SMARTS optical/IR afterglow observations
  84. GRB091029: Swift/UVOT observations
  85. GRB 091029: Enhanced Swift-XRT position
  86. GRB091024 optical observations
  87. GRB 091029: GROND Detection of the Optical/NIR Afterglow
  88. GRB 091029: Swift detection of a burst with an optical counterpart
  89. GRB 091026: GROND Upper Limits
  90. Radio afterglow detection from GRB 091020
  91. GRB 091026: Swift/UVOT Upper Limits
  92. GRB 091026: Enhanced Swift-XRT position
  93. Konus-Wind and Konus-RF observations of GRB 091024
  94. GRB 091026: Swift detection of a Gamma Ray Burst
  95. GRB091024 Swift/UVOT Upper Limits
  96. GRB 091024: Super-LOTIS early observations
  97. GRB 091024: Fermi GBM Observations
  98. GRB 091024: Swift-XRT team refined analysis
  99. GRB 091024 : Faulkes Telescope North - Afterglow Confirmation
  100. GRB 091024: GRAS004 optical observations

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