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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. GRB060206, optical observations
  2. GRB 060210 : Xinglong and Lulin optical limit
  3. GRB060210: Optical Observations
  4. GRB060210: Gemini absorption spectroscopy
  5. GRB060210: Early Optical Observations
  6. GRB 060210: optical evolution
  7. GRB060210:Faulkes Telescope North Afterglow Confirmation
  8. GRB 060210: candidate afterglow
  9. GRB 060210: Swift detection of a burst
  10. GRB060210: Optical afterglow
  11. GRB 060206: Swift/UVOT Observations
  12. Swift-BAT trigger 180931 is not a GRB
  13. GRB060209: RTT150 optical observations
  14. GRB 060209 : TAROT optical observation
  15. GRB060209A: MASTER optical observation
  16. GRB 060209(?): Swift-BAT detection of a possible burst
  17. GRB 060206: near-infrared observations (JK' imaging)
  18. GRB 060206: WSRT Radio Observations
  19. GRB 060203: Swift/UVOT upper limits
  20. GRB 060206: TTT Observations
  21. GRB 060206: More PROMPT Detections
  22. GRB 060121 : WIDGET Pre-trigger limit
  23. GRB 060206: Tenagra II Observations
  24. GRB 060206: PROMPT Detections
  25. Retraction of orphan GRB afterglow candidate
  26. GRB060204a: Swift XRT Source is not GRB Afterglow
  27. GRB 060206: optical observations at Asiago
  28. Orphan GRB Afterglow candidate
  29. GRB 060204b: pseudo-z from spectral parameters of the prompt emission
  30. GRB 060206: Subaru/FOCAS optical spectroscopy
  31. GRB 060206: IR Detection of the Afterglow
  32. GRB 060206: Lick 3m Spectroscopy
  33. GRB 060204A: ROSAT Pointing
  34. GRB 060206: Super-LOTIS observations
  35. GRB060204A: Swift/UVOT observations
  36. GRB 060206: Swift-BAT refined analysis
  37. GRB 060206 : Lulin optical observations
  38. GRB060206: SDSS Pre-Burst Observations
  39. GRB060206: Swift XRT Refined Analysis
  40. GRB060206: Liverpool Telescope observation
  41. GRB 060206: Spectroscopic Redshift
  42. GRB060206: P60 Optical Observations
  43. GRB 060206: KAIT observations
  44. GRB060206: Swift XRT Position
  45. GRB060206: SARA Detection
  46. GRB 060206: RAPTOR observations of afterglow candidate variability.
  47. GRB 060206: High redshift burst
  48. GRB060204a: Swift XRT Detection of an Afterglow Candidate
  49. GRB060206 - Swift UVOT Confirmation of Optical Afterglow
  50. GRB060206: Optical afterglow
  51. GRB060206: Swift-BAT detection of a burst
  52. GRB 060204C: XRT analysis of Swift J061223.0+701243.9
  53. GRB060203: WHT Z-band observations
  54. BAT GRB 060204C is probably not a GRB
  55. GRB060204C: optical observation
  56. GRB 060204B: BVRi-band detections of optical afterglow
  57. GRB 060204A: Swift XRT upper limit
  58. GRB 060204A: FRAM optical observations
  59. GRB060204B: Swift/UVOT refined analysis
  60. GRB 060204C: optical observations
  61. Swift XRT Observation of GRB 060204C
  62. GRB 060204B: Swift-BAT refined analysis
  63. GRB 060204B: ART early limit
  64. GRB060204B: Swift XRT Team Refined Analysis
  65. GRB 060204C: OSN limits
  66. GRB 060204b: Keck/LRIS Afterglow Confirmation
  67. GRB 060204C: BOOTES-IR optical limits
  68. GRB 060204C: Liverpool Telescopes optical limit
  69. GRB 060204C: ROTSE-III Optical Limits
  70. GRB 060204C: Swift-BAT detection of a burst
  71. GRB 060124: Radio Observations
  72. GRB060204B: Faulkes OT candidate
  73. GRB 060204B: ART optical limit
  74. GRB 060204A: further INTEGRAL results
  75. GRB060204B, optical observation
  76. GRB060204B - SDSS pre-burst observations
  77. GRB 060203: Swift-BAT refined analysis
  78. GRB 060204B: Swift detection of a burst
  79. GRB 060204: a long GRB detected by INTEGRAL
  80. GRB 060202: UKIRT/WFCAM K-band and KeckI/LRIS I-band Observation
  81. GRB 060203: RTT150 optical observations
  82. GRB060203: Swift XRT Team Refined Analysis
  83. GRB060203 - Swift UVOT observation
  84. Swift-BAT trigger is GRB 060203
  85. GRB 060203: IR Counterpart
  86. GRB060203: Observations with SARA
  87. GRB 060203: P60 Confirmation of Optical Afterglow
  88. Possible GRB 060203: candidate optical counterpart
  89. Swift BAT Trigger 180151: Swift XRT source detection
  90. Possible GRB 060203: optical observations at Asiago
  91. GRB 060202: PROMPT Observations
  92. Swift-BAT trigger 180151 is unknown origin at this time
  93. GRB 060202: GETS observation
  94. GRB 060202: Gemini-N J, H, K_s observations
  95. GRB 060202 : Kiso B and R band limit
  96. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  97. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  98. GRB 060202: Refined analysis of the Swift-BAT burst
  99. GRB060202, optical observation
  100. GRB 060202: Swift/UVOT upper limits

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