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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 060421: TTT Observations
  2. OT 060420: Likely Not a New Cosmic Transient
  3. No OT 060420 in MASCOT images
  4. Swift-BAT detection of Mrk 421
  5. OT 060420: CONCAM detection of a candidate new magnitude 5 optical
  6. GRB060421: Swift/UVOT observations
  7. GRB 060421: Swift-BAT Refined Analysis
  8. GRB 060421: Swift-XRT refined analysis
  9. GRB 060418: prediction of t_break
  10. GRB060418: optical observations
  11. Konus-Wind observation of GRB 060418
  12. GRB(?)060421:MASTER optical limit
  13. GRB(?)060421 : XRT position
  14. Possible GRB060421: BART limits
  15. GRB(?) 060421: Swift detection of a burst
  16. Erratum of GCN 4983 for GRB 060418 IR follow-up
  17. GRB 060418 : IR afterglow observations
  18. GRB 060418 : Lulin Optical follow-up
  19. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  20. GRB 060418: Radio Observations
  21. GRB060418, BVRcIc field calibration
  22. GRB060418: Swift/UVOT Observations
  23. GRB060418: Optical Observations
  24. GRB 060418: FRAM early afterglow observation
  25. GRB 060418: Refined Analysis of the Swift-BAT burst
  26. VLT/UVES observations of GRB060418
  27. GRB060418: Swift XRT Team Refined Analysis
  28. GRB 060418, SMARTS continuing afterglow observations
  29. GRB 060418: PROMPT Detections
  30. GRB 060418, SMARTS optical/IR afterglow observations
  31. GRB060418: Magellan/MIKE Spectroscopic Redshift
  32. GRB060418 : LT optical afterglow observation
  33. GRB 060418: REM candidate afterglow
  34. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  35. SGR 1900+14: Refined analysis of the Swift-BAT outburst
  36. GRB060413: Swift/UVOT upper limits
  37. GRB 060413: REM NIR Observations
  38. SGR 1900+14: Swift detection of an outburst
  39. GRB 060413: Refined analysis of the Swift-BAT burst
  40. GRB 060413: Watcher UBVR observations
  41. GRB 060413: XRT refined analysis
  42. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  43. GRB 060413: Swift detection of a burst
  44. GRB060403: optical observations
  45. GRB 060403 Optical observations
  46. GRB 060403: MITSuME optical observation
  47. GRB060403: Optical Limit
  48. GRB060403: XRT refined analysis
  49. GRB 060403: Swift/UVOT upper limits
  50. HETE Triggers H4043 and H4044 Not Due to New Cosmic Source
  51. SGR 1900+14: BAT observations
  52. GRB 060403: Refined analysis of the Swift-BAT burst
  53. GRB060403: Swift XRT refined position
  54. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  55. GRB 060403: Swift detection of a burst
  56. HETE trigger H4044: RTT150 optical observations
  57. GRB060331: Swift/UVOT upper limits
  58. H4044, a Repeat Outburst From The Source of H4043 (="GRB060331")
  59. Swift XRT observations of the HETE transient H4043
  60. HETE Trigger 4043: ROTSE-III Optical Limits
  61. Correction to Circular 4938, =H4043, an unusual high energy transient observed by HETE
  62. H4043, an unusual high-energy transient observed by HETE
  63. GRB 060322: LNA optical limit
  64. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  65. INTEGRAL and XMM ToO observations of SGR1900+14
  66. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  67. SGR 1900+14: Swift-BAT detection of a bright outburst
  68. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  69. GRB 060323 : WIDGET simultaneous optical observations
  70. GRB 060323: Early optical observation at Xinglong
  71. GRB060218, optical observations
  72. GRB 060322: Confirmation of Swift XRT afterglow
  73. GRB 060211A: optical observation
  74. GRB060323: optical limit
  75. GRB060211B: optical observation
  76. SGR 1900+14: CORRECTION to GCN 4923
  77. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  78. SGR 1900+14: Swift detection of renewed activity
  79. GRB060323: NOT optical observations
  80. GRB 060322: IAC80 optical observations
  81. GRB 060322: Swift XRT afterglow candidate
  82. GRB060323: P60 Observations
  83. GRB 060323: Swift/UVOT Observations
  84. GRB 060323: optical afterglow confirmed
  85. GRB060323: NOT observations
  86. GRB 060323: Optical Observations
  87. GRB 060323: Tautenburg OT candidate retraction
  88. GRB 060323: Refined analysis of the Swift-BAT burst
  89. GRB 060323: optical observations at TNG
  90. GRB 060323: Swift XRT refined analysis
  91. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  92. GRB 060323: Swift/XRT position
  93. GRB 060322: Refined analysis of the Swift-BAT burst
  94. GRB060323, optical observation
  95. GRB060323 - SDSS Pre-Burst Observations
  96. GRB 060323: Swift detection of a burst with a possible optical afterglow
  97. GRB 060322: Swift-BAT detection of a 200-sec burst
  98. GRB060219: optical observation
  99. GRB060206: optical observation
  100. GRB060218/SN2006aj: optical observations

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