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

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