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

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