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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. GRB060428A: Swift/UVOT observations.
  2. GRB060428B, optical observation
  3. GRB 060428A: Refined analysis of the Swift-BAT burst
  4. GRB 060428b : Kiso R-band limit
  5. GRB060427:MASTER optical limit
  6. GRB 060428b: Optical afterglow candidate
  7. GRB060428A: Swift XRT Team refined analysis
  8. GRB 060428B: Swift detection of a burst
  9. GRB 060427: NIR observations
  10. GRB060427: Xinglong optical Observations
  11. GRB 060428: Swift detection of a burst
  12. GRB 060427: NOT observations
  13. GRB 060427: Swift/UVOT upper limits.
  14. GRB 060427: Refined analysis of the Swift-BAT burst
  15. GRB060427: Swift XRT Team refined analysis
  16. GRB060418: Swift XRT Team Further Refined Analysis
  17. GRB060425:MASTER survey observations
  18. GRB 060427, optical observation
  19. GRB 060427: Swift detection of a burst
  20. GRB 060425: IPN localization and KW spectrum of a short, hard burst
  21. An interactive program for GRB pseudo-redshift computations
  22. GRB060424: optical afterglow detection
  23. GRB060418: Further Analysis of MIKE Spectroscopy
  24. GRB 060424: Refined analysis of the Swift-BAT burst
  25. GRB 060424: Swift detection of a burst
  26. GRB 060421: TTT Observations
  27. OT 060420: Likely Not a New Cosmic Transient
  28. No OT 060420 in MASCOT images
  29. Swift-BAT detection of Mrk 421
  30. OT 060420: CONCAM detection of a candidate new magnitude 5 optical
  31. GRB060421: Swift/UVOT observations
  32. GRB 060421: Swift-BAT Refined Analysis
  33. GRB 060421: Swift-XRT refined analysis
  34. GRB 060418: prediction of t_break
  35. GRB060418: optical observations
  36. Konus-Wind observation of GRB 060418
  37. GRB(?)060421:MASTER optical limit
  38. GRB(?)060421 : XRT position
  39. Possible GRB060421: BART limits
  40. GRB(?) 060421: Swift detection of a burst
  41. Erratum of GCN 4983 for GRB 060418 IR follow-up
  42. GRB 060418 : IR afterglow observations
  43. GRB 060418 : Lulin Optical follow-up
  44. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  45. GRB 060418: Radio Observations
  46. GRB060418, BVRcIc field calibration
  47. GRB060418: Swift/UVOT Observations
  48. GRB060418: Optical Observations
  49. GRB 060418: FRAM early afterglow observation
  50. GRB 060418: Refined Analysis of the Swift-BAT burst
  51. VLT/UVES observations of GRB060418
  52. GRB060418: Swift XRT Team Refined Analysis
  53. GRB 060418, SMARTS continuing afterglow observations
  54. GRB 060418: PROMPT Detections
  55. GRB 060418, SMARTS optical/IR afterglow observations
  56. GRB060418: Magellan/MIKE Spectroscopic Redshift
  57. GRB060418 : LT optical afterglow observation
  58. GRB 060418: REM candidate afterglow
  59. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  60. SGR 1900+14: Refined analysis of the Swift-BAT outburst
  61. GRB060413: Swift/UVOT upper limits
  62. GRB 060413: REM NIR Observations
  63. SGR 1900+14: Swift detection of an outburst
  64. GRB 060413: Refined analysis of the Swift-BAT burst
  65. GRB 060413: Watcher UBVR observations
  66. GRB 060413: XRT refined analysis
  67. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  68. GRB 060413: Swift detection of a burst
  69. GRB060403: optical observations
  70. GRB 060403 Optical observations
  71. GRB 060403: MITSuME optical observation
  72. GRB060403: Optical Limit
  73. GRB060403: XRT refined analysis
  74. GRB 060403: Swift/UVOT upper limits
  75. HETE Triggers H4043 and H4044 Not Due to New Cosmic Source
  76. SGR 1900+14: BAT observations
  77. GRB 060403: Refined analysis of the Swift-BAT burst
  78. GRB060403: Swift XRT refined position
  79. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  80. GRB 060403: Swift detection of a burst
  81. HETE trigger H4044: RTT150 optical observations
  82. GRB060331: Swift/UVOT upper limits
  83. H4044, a Repeat Outburst From The Source of H4043 (="GRB060331")
  84. Swift XRT observations of the HETE transient H4043
  85. HETE Trigger 4043: ROTSE-III Optical Limits
  86. Correction to Circular 4938, =H4043, an unusual high energy transient observed by HETE
  87. H4043, an unusual high-energy transient observed by HETE
  88. GRB 060322: LNA optical limit
  89. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  90. INTEGRAL and XMM ToO observations of SGR1900+14
  91. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  92. SGR 1900+14: Swift-BAT detection of a bright outburst
  93. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  94. GRB 060323 : WIDGET simultaneous optical observations
  95. GRB 060323: Early optical observation at Xinglong
  96. GRB060218, optical observations
  97. GRB 060322: Confirmation of Swift XRT afterglow
  98. GRB 060211A: optical observation
  99. GRB060323: optical limit
  100. GRB060211B: optical observation

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