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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. GRB060211: Faulkes North observation
  2. GRB 060211: ROTSE-III Optical Limits
  3. GRB 060211: Swift detection of a long burst
  4. GRB 060210: Refined analysis of the Swift-BAT burst
  5. GRB060210: Swift XRT Refined Analysis
  6. GRB060206, optical observations
  7. GRB 060210 : Xinglong and Lulin optical limit
  8. GRB060210: Optical Observations
  9. GRB060210: Gemini absorption spectroscopy
  10. GRB060210: Early Optical Observations
  11. GRB 060210: optical evolution
  12. GRB060210:Faulkes Telescope North Afterglow Confirmation
  13. GRB 060210: candidate afterglow
  14. GRB 060210: Swift detection of a burst
  15. GRB060210: Optical afterglow
  16. GRB 060206: Swift/UVOT Observations
  17. Swift-BAT trigger 180931 is not a GRB
  18. GRB060209: RTT150 optical observations
  19. GRB 060209 : TAROT optical observation
  20. GRB060209A: MASTER optical observation
  21. GRB 060209(?): Swift-BAT detection of a possible burst
  22. GRB 060206: near-infrared observations (JK' imaging)
  23. GRB 060206: WSRT Radio Observations
  24. GRB 060203: Swift/UVOT upper limits
  25. GRB 060206: TTT Observations
  26. GRB 060206: More PROMPT Detections
  27. GRB 060121 : WIDGET Pre-trigger limit
  28. GRB 060206: Tenagra II Observations
  29. GRB 060206: PROMPT Detections
  30. Retraction of orphan GRB afterglow candidate
  31. GRB060204a: Swift XRT Source is not GRB Afterglow
  32. GRB 060206: optical observations at Asiago
  33. Orphan GRB Afterglow candidate
  34. GRB 060204b: pseudo-z from spectral parameters of the prompt emission
  35. GRB 060206: Subaru/FOCAS optical spectroscopy
  36. GRB 060206: IR Detection of the Afterglow
  37. GRB 060206: Lick 3m Spectroscopy
  38. GRB 060204A: ROSAT Pointing
  39. GRB 060206: Super-LOTIS observations
  40. GRB060204A: Swift/UVOT observations
  41. GRB 060206: Swift-BAT refined analysis
  42. GRB 060206 : Lulin optical observations
  43. GRB060206: SDSS Pre-Burst Observations
  44. GRB060206: Swift XRT Refined Analysis
  45. GRB060206: Liverpool Telescope observation
  46. GRB 060206: Spectroscopic Redshift
  47. GRB060206: P60 Optical Observations
  48. GRB 060206: KAIT observations
  49. GRB060206: Swift XRT Position
  50. GRB060206: SARA Detection
  51. GRB 060206: RAPTOR observations of afterglow candidate variability.
  52. GRB 060206: High redshift burst
  53. GRB060204a: Swift XRT Detection of an Afterglow Candidate
  54. GRB060206 - Swift UVOT Confirmation of Optical Afterglow
  55. GRB060206: Optical afterglow
  56. GRB060206: Swift-BAT detection of a burst
  57. GRB 060204C: XRT analysis of Swift J061223.0+701243.9
  58. GRB060203: WHT Z-band observations
  59. BAT GRB 060204C is probably not a GRB
  60. GRB060204C: optical observation
  61. GRB 060204B: BVRi-band detections of optical afterglow
  62. GRB 060204A: Swift XRT upper limit
  63. GRB 060204A: FRAM optical observations
  64. GRB060204B: Swift/UVOT refined analysis
  65. GRB 060204C: optical observations
  66. Swift XRT Observation of GRB 060204C
  67. GRB 060204B: Swift-BAT refined analysis
  68. GRB 060204B: ART early limit
  69. GRB060204B: Swift XRT Team Refined Analysis
  70. GRB 060204C: OSN limits
  71. GRB 060204b: Keck/LRIS Afterglow Confirmation
  72. GRB 060204C: BOOTES-IR optical limits
  73. GRB 060204C: Liverpool Telescopes optical limit
  74. GRB 060204C: ROTSE-III Optical Limits
  75. GRB 060204C: Swift-BAT detection of a burst
  76. GRB 060124: Radio Observations
  77. GRB060204B: Faulkes OT candidate
  78. GRB 060204B: ART optical limit
  79. GRB 060204A: further INTEGRAL results
  80. GRB060204B, optical observation
  81. GRB060204B - SDSS pre-burst observations
  82. GRB 060203: Swift-BAT refined analysis
  83. GRB 060204B: Swift detection of a burst
  84. GRB 060204: a long GRB detected by INTEGRAL
  85. GRB 060202: UKIRT/WFCAM K-band and KeckI/LRIS I-band Observation
  86. GRB 060203: RTT150 optical observations
  87. GRB060203: Swift XRT Team Refined Analysis
  88. GRB060203 - Swift UVOT observation
  89. Swift-BAT trigger is GRB 060203
  90. GRB 060203: IR Counterpart
  91. GRB060203: Observations with SARA
  92. GRB 060203: P60 Confirmation of Optical Afterglow
  93. Possible GRB 060203: candidate optical counterpart
  94. Swift BAT Trigger 180151: Swift XRT source detection
  95. Possible GRB 060203: optical observations at Asiago
  96. GRB 060202: PROMPT Observations
  97. Swift-BAT trigger 180151 is unknown origin at this time
  98. GRB 060202: GETS observation
  99. GRB 060202: Gemini-N J, H, K_s observations
  100. GRB 060202 : Kiso B and R band limit

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