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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 060501: Swift detection of a burst
  2. IPN triangulation of GRB060429 (short/hard)
  3. Konus-Wind observation of GRB 060427B
  4. GRB060428B - SDSS Pre-Burst Observations
  5. GRB060428B: optical observation
  6. GRB060428B: possible detection of an optical counterpart by Swift/UVOT.
  7. GRB 060428B: MDM Observations
  8. GRB 060428A: PROMPT Observations
  9. GRB 060427B: MASTER optical observations
  10. GRB060428B: Swift XRT Team refined analysis
  11. GRB 060427B: IPN localization of a short hard burst
  12. GRB 060428B: Refined analysis of the Swift-BAT burst
  13. GRB 060428B: Xinglong I-band limit
  14. GRB 060428B: KAIT observations
  15. GRB060425:MASTER optical limit
  16. GRB 051117A: Bright host galaxy not confirmed
  17. GRB060428A: Swift/UVOT observations.
  18. GRB060428B, optical observation
  19. GRB 060428A: Refined analysis of the Swift-BAT burst
  20. GRB 060428b : Kiso R-band limit
  21. GRB060427:MASTER optical limit
  22. GRB 060428b: Optical afterglow candidate
  23. GRB060428A: Swift XRT Team refined analysis
  24. GRB 060428B: Swift detection of a burst
  25. GRB 060427: NIR observations
  26. GRB060427: Xinglong optical Observations
  27. GRB 060428: Swift detection of a burst
  28. GRB 060427: NOT observations
  29. GRB 060427: Swift/UVOT upper limits.
  30. GRB 060427: Refined analysis of the Swift-BAT burst
  31. GRB060427: Swift XRT Team refined analysis
  32. GRB060418: Swift XRT Team Further Refined Analysis
  33. GRB060425:MASTER survey observations
  34. GRB 060427, optical observation
  35. GRB 060427: Swift detection of a burst
  36. GRB 060425: IPN localization and KW spectrum of a short, hard burst
  37. An interactive program for GRB pseudo-redshift computations
  38. GRB060424: optical afterglow detection
  39. GRB060418: Further Analysis of MIKE Spectroscopy
  40. GRB 060424: Refined analysis of the Swift-BAT burst
  41. GRB 060424: Swift detection of a burst
  42. GRB 060421: TTT Observations
  43. OT 060420: Likely Not a New Cosmic Transient
  44. No OT 060420 in MASCOT images
  45. Swift-BAT detection of Mrk 421
  46. OT 060420: CONCAM detection of a candidate new magnitude 5 optical
  47. GRB060421: Swift/UVOT observations
  48. GRB 060421: Swift-BAT Refined Analysis
  49. GRB 060421: Swift-XRT refined analysis
  50. GRB 060418: prediction of t_break
  51. GRB060418: optical observations
  52. Konus-Wind observation of GRB 060418
  53. GRB(?)060421:MASTER optical limit
  54. GRB(?)060421 : XRT position
  55. Possible GRB060421: BART limits
  56. GRB(?) 060421: Swift detection of a burst
  57. Erratum of GCN 4983 for GRB 060418 IR follow-up
  58. GRB 060418 : IR afterglow observations
  59. GRB 060418 : Lulin Optical follow-up
  60. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  61. GRB 060418: Radio Observations
  62. GRB060418, BVRcIc field calibration
  63. GRB060418: Swift/UVOT Observations
  64. GRB060418: Optical Observations
  65. GRB 060418: FRAM early afterglow observation
  66. GRB 060418: Refined Analysis of the Swift-BAT burst
  67. VLT/UVES observations of GRB060418
  68. GRB060418: Swift XRT Team Refined Analysis
  69. GRB 060418, SMARTS continuing afterglow observations
  70. GRB 060418: PROMPT Detections
  71. GRB 060418, SMARTS optical/IR afterglow observations
  72. GRB060418: Magellan/MIKE Spectroscopic Redshift
  73. GRB060418 : LT optical afterglow observation
  74. GRB 060418: REM candidate afterglow
  75. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  76. SGR 1900+14: Refined analysis of the Swift-BAT outburst
  77. GRB060413: Swift/UVOT upper limits
  78. GRB 060413: REM NIR Observations
  79. SGR 1900+14: Swift detection of an outburst
  80. GRB 060413: Refined analysis of the Swift-BAT burst
  81. GRB 060413: Watcher UBVR observations
  82. GRB 060413: XRT refined analysis
  83. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  84. GRB 060413: Swift detection of a burst
  85. GRB060403: optical observations
  86. GRB 060403 Optical observations
  87. GRB 060403: MITSuME optical observation
  88. GRB060403: Optical Limit
  89. GRB060403: XRT refined analysis
  90. GRB 060403: Swift/UVOT upper limits
  91. HETE Triggers H4043 and H4044 Not Due to New Cosmic Source
  92. SGR 1900+14: BAT observations
  93. GRB 060403: Refined analysis of the Swift-BAT burst
  94. GRB060403: Swift XRT refined position
  95. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  96. GRB 060403: Swift detection of a burst
  97. HETE trigger H4044: RTT150 optical observations
  98. GRB060331: Swift/UVOT upper limits
  99. H4044, a Repeat Outburst From The Source of H4043 (="GRB060331")
  100. Swift XRT observations of the HETE transient H4043

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