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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 050607: PROMPT VRcIc Observations
  2. GRB 050607: RAPTOR-S Early Optical Limits
  3. GRB050607: KAIT optical limits
  4. GRB 050525a, Mid-Infrared Observations
  5. GRB 050607: Optical decay and spectral slope
  6. GRB 050607: MDM Observations
  7. GRB050607,optical observation
  8. GRB 050607 - XRT refined data analysis
  9. Optical Afterglow of GRB 050607
  10. GRB050607 optical limit by "Pi of the Sky"
  11. GRB050607: Swift Detection of a long GRB
  12. GRB050607: P60 Observations
  13. GRB050607: prompt REM observations
  14. GRB 050603: prediction of t_break
  15. Limits on a SN in the field of GRB 050509b
  16. GRB 050603: Redshift
  17. GRB 050603 - XRT data analysis of the first day
  18. Konus-Wind observation of GRB 050603
  19. GRB 050603: Analysis of UVOT data
  20. GRB050603: Fading Afterglow observed by Swift UVOT
  21. GRB050603, submillimetre observations
  22. GRB 050603: Swift XRT Position
  23. GRB050603: Radio Detection
  24. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  25. GRB 050603: Afterglow Identification from LCO
  26. GRB 050603: INTEGRAL shows it is not a short GRB
  27. Swift/BAT Detection of GRB050603
  28. GRB 050408: jet break in the XRT light curve
  29. GRB 050525a, infrared observations
  30. GRB 050525a, SMARTS optical/IR afterglow observations
  31. GRB050528, XRT observations
  32. Correction to GCN Circ 3502 on GRB 050528
  33. GRB050528: updated Liverpool Telescope limits
  34. Swift-BAT GRB 050528: a soft burst
  35. Update on Swift-BAT GRB 050528 (Trigger 130679)
  36. GRB050528: BOOTES optical candidate (retraction)
  37. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  38. GRB050528: BOOTES optical candidate
  39. Possible GRB050528: no candidate from Liverpool Telescope
  40. Swift-BAT detection of possible GRB 050528
  41. GRB050525a: Radio Observations
  42. GRB 050509b: refined XRT/Chandra afterglow position analysis
  43. GRB 050525: RTT150, Optical observations
  44. GRB050525a: optical upper limits
  45. GRB 050525a: SARA Observations
  46. GRB 050525B: Swift-BAT observations
  47. GRB 050525: MITSuME Optical Observation in VRI
  48. GRB 050525a: MDM Observations
  49. GRB050525A,optical observation
  50. GRB 050525 : Lulin optical afterglow observations
  51. GRB050525: Super-LOTIS observations
  52. GRB 050525, spectral lag pseudo-redshift
  53. GRB 050525a: Gemini/GMOS Spectra
  54. GRB050306: optical afterglow not confirmed
  55. GRB 050525: BART optical observation
  56. GRB 050525A: BOOTES simultaneous optical observations
  57. GRB 050525A: Swift-BAT refined analysis
  58. GRB050525: Optical observations
  59. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  60. GRB 050525: pseudo-redshift
  61. Swift/UVOT UV and optical detections of GRB 050525
  62. Konus-Wind observation of GRB 050525
  63. GRB 050525: TAROT observations of the early afterglow
  64. INTEGRAL detection of GRB 050525
  65. GRB 050525, infrared observations
  66. GRB 050525: Optical observation
  67. GRB 050525: observatons of the optical afterglow
  68. GRB050525: ROTSE-III Refined Analysis
  69. GRB 050525 - Very Bright, Not Short
  70. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  71. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  72. XRF050522: NIR observations of XRT candidate
  73. XRF 050522: Swift XRT refined analysis
  74. XRF050522: Radio Observations
  75. Swift/UVOT observation of XRF 050522
  76. GRB 050509A: Further I-band imaging
  77. GRB050522,optical observation
  78. GRB050520,optical observation
  79. XRF 050522: Continued NIR P200 Monitoring
  80. RBO Observations of GRB050522
  81. GRB050509b: optical observations
  82. Recent GRB BVRcIc field photometry
  83. GRB050520: Radio Observations
  84. XRF 050522: Swift XRT observation
  85. XRF050522, BVRcIc field photometry
  86. XRF 050522 : Lulin observations
  87. XRF050522: Optical Observations
  88. XRF050522: Near-infrared Observations
  89. XRF 050522: KAIT observations
  90. XRF 050522 detected with INTEGRAL
  91. GRB 050520: VLT/ULTRACAM observations
  92. Swift UVOT Observations of GRB 050520
  93. GRB 050520: Swift XRT refined analysis
  94. XRF050509C: Chandra Afterglow Detection
  95. XRF 050509c: Swift XRT Upper Limit
  96. XRF050509c: Radio Observations
  97. RBO Observations of GRB050520
  98. GRB 050520: P200 Observations
  99. GRB050520: Liverpool Telescope follow-up
  100. RBO Observations of GRB050520

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