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

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