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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. OT 060420: CONCAM detection of a candidate new magnitude 5 optical
  2. GRB060421: Swift/UVOT observations
  3. GRB 060421: Swift-BAT Refined Analysis
  4. GRB 060421: Swift-XRT refined analysis
  5. GRB 060418: prediction of t_break
  6. GRB060418: optical observations
  7. Konus-Wind observation of GRB 060418
  8. GRB(?)060421:MASTER optical limit
  9. GRB(?)060421 : XRT position
  10. Possible GRB060421: BART limits
  11. GRB(?) 060421: Swift detection of a burst
  12. Erratum of GCN 4983 for GRB 060418 IR follow-up
  13. GRB 060418 : IR afterglow observations
  14. GRB 060418 : Lulin Optical follow-up
  15. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  16. GRB 060418: Radio Observations
  17. GRB060418, BVRcIc field calibration
  18. GRB060418: Swift/UVOT Observations
  19. GRB060418: Optical Observations
  20. GRB 060418: FRAM early afterglow observation
  21. GRB 060418: Refined Analysis of the Swift-BAT burst
  22. VLT/UVES observations of GRB060418
  23. GRB060418: Swift XRT Team Refined Analysis
  24. GRB 060418, SMARTS continuing afterglow observations
  25. GRB 060418: PROMPT Detections
  26. GRB 060418, SMARTS optical/IR afterglow observations
  27. GRB060418: Magellan/MIKE Spectroscopic Redshift
  28. GRB060418 : LT optical afterglow observation
  29. GRB 060418: REM candidate afterglow
  30. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  31. SGR 1900+14: Refined analysis of the Swift-BAT outburst
  32. GRB060413: Swift/UVOT upper limits
  33. GRB 060413: REM NIR Observations
  34. SGR 1900+14: Swift detection of an outburst
  35. GRB 060413: Refined analysis of the Swift-BAT burst
  36. GRB 060413: Watcher UBVR observations
  37. GRB 060413: XRT refined analysis
  38. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  39. GRB 060413: Swift detection of a burst
  40. GRB060403: optical observations
  41. GRB 060403 Optical observations
  42. GRB 060403: MITSuME optical observation
  43. GRB060403: Optical Limit
  44. GRB060403: XRT refined analysis
  45. GRB 060403: Swift/UVOT upper limits
  46. HETE Triggers H4043 and H4044 Not Due to New Cosmic Source
  47. SGR 1900+14: BAT observations
  48. GRB 060403: Refined analysis of the Swift-BAT burst
  49. GRB060403: Swift XRT refined position
  50. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  51. GRB 060403: Swift detection of a burst
  52. HETE trigger H4044: RTT150 optical observations
  53. GRB060331: Swift/UVOT upper limits
  54. H4044, a Repeat Outburst From The Source of H4043 (="GRB060331")
  55. Swift XRT observations of the HETE transient H4043
  56. HETE Trigger 4043: ROTSE-III Optical Limits
  57. Correction to Circular 4938, =H4043, an unusual high energy transient observed by HETE
  58. H4043, an unusual high-energy transient observed by HETE
  59. GRB 060322: LNA optical limit
  60. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  61. INTEGRAL and XMM ToO observations of SGR1900+14
  62. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  63. SGR 1900+14: Swift-BAT detection of a bright outburst
  64. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  65. GRB 060323 : WIDGET simultaneous optical observations
  66. GRB 060323: Early optical observation at Xinglong
  67. GRB060218, optical observations
  68. GRB 060322: Confirmation of Swift XRT afterglow
  69. GRB 060211A: optical observation
  70. GRB060323: optical limit
  71. GRB060211B: optical observation
  72. SGR 1900+14: CORRECTION to GCN 4923
  73. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  74. SGR 1900+14: Swift detection of renewed activity
  75. GRB060323: NOT optical observations
  76. GRB 060322: IAC80 optical observations
  77. GRB 060322: Swift XRT afterglow candidate
  78. GRB060323: P60 Observations
  79. GRB 060323: Swift/UVOT Observations
  80. GRB 060323: optical afterglow confirmed
  81. GRB060323: NOT observations
  82. GRB 060323: Optical Observations
  83. GRB 060323: Tautenburg OT candidate retraction
  84. GRB 060323: Refined analysis of the Swift-BAT burst
  85. GRB 060323: optical observations at TNG
  86. GRB 060323: Swift XRT refined analysis
  87. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  88. GRB 060323: Swift/XRT position
  89. GRB 060322: Refined analysis of the Swift-BAT burst
  90. GRB060323, optical observation
  91. GRB060323 - SDSS Pre-Burst Observations
  92. GRB 060323: Swift detection of a burst with a possible optical afterglow
  93. GRB 060322: Swift-BAT detection of a 200-sec burst
  94. GRB060219: optical observation
  95. GRB060206: optical observation
  96. GRB060218/SN2006aj: optical observations
  97. GRB 060218/SN 2006aj, LNA optical observation
  98. GRB060218: Refined photometric calibration of comparison stars
  99. GRB 060319: WHT K-band candidate afterglow
  100. GRB 060319: IAC-80 optical observations

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