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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 071010B: TLS 3rd Epoch - finally a break??
  2. GRB 071011: MITSuME Optical Observations
  3. GRB 070920A: deep optical observations at the NOT
  4. GRB 071010B: Photometry after 1.6 days
  5. GRB 071010B: Keck/LRIS Photometry
  6. GRB 071010B: TLS 2nd Epoch, refined analysis
  7. GRB 071013: TLS Upper Limit
  8. Correction to GCN circular no. # 6915 for GRB 071010B
  9. VLA detection of radio afterglow of GRB 071010B
  10. VLA non-detection of GRB 071011
  11. GRB 071013: Optical observations
  12. GRB 071013: optical observations at NOT
  13. GRB 071013, Swift-BAT refined analysis
  14. GRB071013: optical limit
  15. GRB071010B, BVRcIc field calibration
  16. GRB 20071013: Xinglong TNT optical Upper Limit
  17. GRB 071013: Swift detection of a burst
  18. GRB 071010C Swift-BAT detection of a burst
  19. GRB 071011: Optical Limit after 13.95hrs
  20. GRB 071011: Xinglong TNT Optical afterglow observations
  21. GRB 071010B correction to GCN 6892 optical observations
  22. GRB 071011: Swift-XRT refined analysis
  23. VLA non-detection of GRB 071010A
  24. GRB 071011: NAYUTA Optical Observation, correction to GCN6886
  25. GRB 071011, Optical afterglow
  26. GRB 071011: Confirmation of P60 optical afterglow
  27. GRB 071010B: Optical Detection
  28. GRB 071011: Kanazawa Optical limits
  29. GRB 071011: P60 Optical Afterglow Candidate
  30. GRB 071011: MARGE Optical Limits
  31. GRB 071010B: Super-LOTIS upper limit
  32. GRB 071010B optical photometry
  33. GRB 071011: XRT afterglow detection
  34. GRB 071010B: Keck/LRIS Spectroscopy
  35. GRB 071011, Swift-BAT refined analysis
  36. GRB 071010B: Gemini Spectroscopic Observations
  37. GRB 071011: Early Super-LOTIS Observations
  38. GRB 071011: NAYUTA Optical Observation
  39. GRB 071010A: Continued Keck Imaging
  40. GRB 071010B: Bright OT confirmed with TLS
  41. GRB 071011: Optical afterglow candidate
  42. GRB 071011: Swift detection of a burst
  43. Optical Observation: GRB 071010
  44. Optical observations: GRB 071010A
  45. Konus-Wind observation of GRB 071010B
  46. GRB071010B: Swift/XRT detection
  47. GRB 071010B, Swift-BAT refined analysis
  48. GRB 071010A: bright NIR afterglow
  49. GRB 071006, Swift-BAT refined analysis
  50. GRB071008: optical observations
  51. GRB 071010B possible optical transient
  52. GRB 071010A: Keck/LRIS Photometry
  53. GRB 071010B: Swift detection of a burst
  54. GRB 071010: Swift-XRT observation
  55. GRB 071008, Swift-BAT refined analysis
  56. GRB 071010, Swift-BAT refined analysis
  57. Konus-Wind observation of GRB 071006
  58. GRB071008: Swift-XRT observation
  59. GRB 071010 REM NIR observations
  60. GRB 071010: Keck/LRIS Spectroscopy
  61. GRB 071010: TAROT La Silla observatory photometry of the afterglow
  62. GRB 071010: Rapid PROMPT Detections
  63. GRB 071010: Keck Observations of the Afterglow
  64. GRB 071010: TAROT La Silla observatory detection of the afterglow
  65. GRB 071010: Swift detection of a burst
  66. GRB 071006 Swift-BAT detection of a burst
  67. GRB071008: IAC80 observation
  68. GRB 071008: Swift detection of a burst
  69. GRB 071003: XRT refined analysis
  70. GRB070920A: MAGIC telescope GeV observation
  71. Radio detection of GRB 071003 with the VLA
  72. GRB 070810B: further XRT analysis
  73. GRB 071003: VLT spectroscopy
  74. GRB 071003: Keck spectroscopy
  75. Konus-Wind observation of GRB 071003
  76. GRB071003: Faulkes Telescope North observations
  77. GRB 071003: Possible rebrightening
  78. GRB 071003 : Lulin R-band observations
  79. GRB 071003: Swift XRT position
  80. GRB 071003: OA power-law decay indices from KAIT
  81. GRB 071003: Keck HIRES spectroscopy
  82. GRB 071003, Swift-BAT refined analysis
  83. GRB 071003: MARGE Observations
  84. GRB 071003 Optical observations
  85. GRB 071003: P60 Confirmation of Optical Afterglow
  86. GRB 071003: KAIT optical afterglow observations
  87. GRB 071003: Swift detection of a bright burst
  88. GRB 070714B: host galaxy spectroscopic redshift
  89. GRB 071001: Swift-XRT Team refined analysis
  90. GRB 071001, Swift-BAT refined analysis
  91. Faulkes Telescope South observations of GRB 071001
  92. GRB 071001: Swift detection of a burst
  93. VLA observation of GRB 070923
  94. Disregard the Swift-XRT Notices today
  95. GRB 070911, SMARTS optical/IR afterglow observations
  96. GRB070925: Swift-XRT Afterglow confirmation
  97. GRB 070925: Gemini South Imaging
  98. GRB070925: Swift-XRT Position
  99. Update on Swift Status
  100. GRB 070920B: ROTSE-III Early Optical Limits

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