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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 050525a: ARC 3.5-Meter SPIcam Field Calibration
  2. GRB 050626 optical observations
  3. GRB 050626: Swift XRT observations
  4. GRB 050701
  5. GRB 050701, optical observations
  6. GRB 050408: ARC 3.5-meter NIR Observations
  7. GRB 050701: Refined XRT analysis
  8. Swift UVOT observations of GRB 050701
  9. GRB050701: Swift-BAT Refined analysis
  10. GRB 050701: Swift XRT afterglow position
  11. Swift trigger 143708 is really GRB 050701
  12. GRB 050607, radio observations
  13. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  14. GRB 050626 - Correction to GCN 3552
  15. GRB 050626 - a long GRB detected with INTEGRAL
  16. GRB 050525A: Swift Late-Time Decay Rate
  17. GRB050525a: HST Observations
  18. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  19. H3804: A Possible New XRB Detected by HETE
  20. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  21. XRF 050509c: Optical monitoring
  22. Konus-Wind observation of an intermediate burst from SGR 1806-20
  23. IBAS Alert #2512 is NOT a GRB
  24. XRF050509c: Radio Detection
  25. GRB 050416(a): Host Galaxy Redshift Determination
  26. GRB 050607: MDM Observation
  27. GRB 050607 optical decay
  28. GRB 050607: RTT150 optical observations
  29. GRB050607: refined analysis of prompt REM observations
  30. Swift/UVOT observations of GRB050607
  31. GRB 050607 : Lulin R-band observation
  32. GRB 050607: PROMPT VRcIc Observations
  33. GRB 050607: RAPTOR-S Early Optical Limits
  34. GRB050607: KAIT optical limits
  35. GRB 050525a, Mid-Infrared Observations
  36. GRB 050607: Optical decay and spectral slope
  37. GRB 050607: MDM Observations
  38. GRB050607,optical observation
  39. GRB 050607 - XRT refined data analysis
  40. Optical Afterglow of GRB 050607
  41. GRB050607 optical limit by "Pi of the Sky"
  42. GRB050607: Swift Detection of a long GRB
  43. GRB050607: P60 Observations
  44. GRB050607: prompt REM observations
  45. GRB 050603: prediction of t_break
  46. Limits on a SN in the field of GRB 050509b
  47. GRB 050603: Redshift
  48. GRB 050603 - XRT data analysis of the first day
  49. Konus-Wind observation of GRB 050603
  50. GRB 050603: Analysis of UVOT data
  51. GRB050603: Fading Afterglow observed by Swift UVOT
  52. GRB050603, submillimetre observations
  53. GRB 050603: Swift XRT Position
  54. GRB050603: Radio Detection
  55. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  56. GRB 050603: Afterglow Identification from LCO
  57. GRB 050603: INTEGRAL shows it is not a short GRB
  58. Swift/BAT Detection of GRB050603
  59. GRB 050408: jet break in the XRT light curve
  60. GRB 050525a, infrared observations
  61. GRB 050525a, SMARTS optical/IR afterglow observations
  62. GRB050528, XRT observations
  63. Correction to GCN Circ 3502 on GRB 050528
  64. GRB050528: updated Liverpool Telescope limits
  65. Swift-BAT GRB 050528: a soft burst
  66. Update on Swift-BAT GRB 050528 (Trigger 130679)
  67. GRB050528: BOOTES optical candidate (retraction)
  68. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  69. GRB050528: BOOTES optical candidate
  70. Possible GRB050528: no candidate from Liverpool Telescope
  71. Swift-BAT detection of possible GRB 050528
  72. GRB050525a: Radio Observations
  73. GRB 050509b: refined XRT/Chandra afterglow position analysis
  74. GRB 050525: RTT150, Optical observations
  75. GRB050525a: optical upper limits
  76. GRB 050525a: SARA Observations
  77. GRB 050525B: Swift-BAT observations
  78. GRB 050525: MITSuME Optical Observation in VRI
  79. GRB 050525a: MDM Observations
  80. GRB050525A,optical observation
  81. GRB 050525 : Lulin optical afterglow observations
  82. GRB050525: Super-LOTIS observations
  83. GRB 050525, spectral lag pseudo-redshift
  84. GRB 050525a: Gemini/GMOS Spectra
  85. GRB050306: optical afterglow not confirmed
  86. GRB 050525: BART optical observation
  87. GRB 050525A: BOOTES simultaneous optical observations
  88. GRB 050525A: Swift-BAT refined analysis
  89. GRB050525: Optical observations
  90. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  91. GRB 050525: pseudo-redshift
  92. Swift/UVOT UV and optical detections of GRB 050525
  93. Konus-Wind observation of GRB 050525
  94. GRB 050525: TAROT observations of the early afterglow
  95. INTEGRAL detection of GRB 050525
  96. GRB 050525, infrared observations
  97. GRB 050525: Optical observation
  98. GRB 050525: observatons of the optical afterglow
  99. GRB050525: ROTSE-III Refined Analysis
  100. GRB 050525 - Very Bright, Not Short

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