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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. GRB060427: Swift XRT Team refined analysis
  2. GRB060418: Swift XRT Team Further Refined Analysis
  3. GRB060425:MASTER survey observations
  4. GRB 060427, optical observation
  5. GRB 060427: Swift detection of a burst
  6. GRB 060425: IPN localization and KW spectrum of a short, hard burst
  7. An interactive program for GRB pseudo-redshift computations
  8. GRB060424: optical afterglow detection
  9. GRB060418: Further Analysis of MIKE Spectroscopy
  10. GRB 060424: Refined analysis of the Swift-BAT burst
  11. GRB 060424: Swift detection of a burst
  12. GRB 060421: TTT Observations
  13. OT 060420: Likely Not a New Cosmic Transient
  14. No OT 060420 in MASCOT images
  15. Swift-BAT detection of Mrk 421
  16. OT 060420: CONCAM detection of a candidate new magnitude 5 optical
  17. GRB060421: Swift/UVOT observations
  18. GRB 060421: Swift-BAT Refined Analysis
  19. GRB 060421: Swift-XRT refined analysis
  20. GRB 060418: prediction of t_break
  21. GRB060418: optical observations
  22. Konus-Wind observation of GRB 060418
  23. GRB(?)060421:MASTER optical limit
  24. GRB(?)060421 : XRT position
  25. Possible GRB060421: BART limits
  26. GRB(?) 060421: Swift detection of a burst
  27. Erratum of GCN 4983 for GRB 060418 IR follow-up
  28. GRB 060418 : IR afterglow observations
  29. GRB 060418 : Lulin Optical follow-up
  30. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  31. GRB 060418: Radio Observations
  32. GRB060418, BVRcIc field calibration
  33. GRB060418: Swift/UVOT Observations
  34. GRB060418: Optical Observations
  35. GRB 060418: FRAM early afterglow observation
  36. GRB 060418: Refined Analysis of the Swift-BAT burst
  37. VLT/UVES observations of GRB060418
  38. GRB060418: Swift XRT Team Refined Analysis
  39. GRB 060418, SMARTS continuing afterglow observations
  40. GRB 060418: PROMPT Detections
  41. GRB 060418, SMARTS optical/IR afterglow observations
  42. GRB060418: Magellan/MIKE Spectroscopic Redshift
  43. GRB060418 : LT optical afterglow observation
  44. GRB 060418: REM candidate afterglow
  45. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  46. SGR 1900+14: Refined analysis of the Swift-BAT outburst
  47. GRB060413: Swift/UVOT upper limits
  48. GRB 060413: REM NIR Observations
  49. SGR 1900+14: Swift detection of an outburst
  50. GRB 060413: Refined analysis of the Swift-BAT burst
  51. GRB 060413: Watcher UBVR observations
  52. GRB 060413: XRT refined analysis
  53. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  54. GRB 060413: Swift detection of a burst
  55. GRB060403: optical observations
  56. GRB 060403 Optical observations
  57. GRB 060403: MITSuME optical observation
  58. GRB060403: Optical Limit
  59. GRB060403: XRT refined analysis
  60. GRB 060403: Swift/UVOT upper limits
  61. HETE Triggers H4043 and H4044 Not Due to New Cosmic Source
  62. SGR 1900+14: BAT observations
  63. GRB 060403: Refined analysis of the Swift-BAT burst
  64. GRB060403: Swift XRT refined position
  65. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  66. GRB 060403: Swift detection of a burst
  67. HETE trigger H4044: RTT150 optical observations
  68. GRB060331: Swift/UVOT upper limits
  69. H4044, a Repeat Outburst From The Source of H4043 (="GRB060331")
  70. Swift XRT observations of the HETE transient H4043
  71. HETE Trigger 4043: ROTSE-III Optical Limits
  72. Correction to Circular 4938, =H4043, an unusual high energy transient observed by HETE
  73. H4043, an unusual high-energy transient observed by HETE
  74. GRB 060322: LNA optical limit
  75. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  76. INTEGRAL and XMM ToO observations of SGR1900+14
  77. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  78. SGR 1900+14: Swift-BAT detection of a bright outburst
  79. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  80. GRB 060323 : WIDGET simultaneous optical observations
  81. GRB 060323: Early optical observation at Xinglong
  82. GRB060218, optical observations
  83. GRB 060322: Confirmation of Swift XRT afterglow
  84. GRB 060211A: optical observation
  85. GRB060323: optical limit
  86. GRB060211B: optical observation
  87. SGR 1900+14: CORRECTION to GCN 4923
  88. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  89. SGR 1900+14: Swift detection of renewed activity
  90. GRB060323: NOT optical observations
  91. GRB 060322: IAC80 optical observations
  92. GRB 060322: Swift XRT afterglow candidate
  93. GRB060323: P60 Observations
  94. GRB 060323: Swift/UVOT Observations
  95. GRB 060323: optical afterglow confirmed
  96. GRB060323: NOT observations
  97. GRB 060323: Optical Observations
  98. GRB 060323: Tautenburg OT candidate retraction
  99. GRB 060323: Refined analysis of the Swift-BAT burst
  100. GRB 060323: optical observations at TNG

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