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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: Swift-XRT refined analysis
  2. GRB 060418: prediction of t_break
  3. GRB060418: optical observations
  4. Konus-Wind observation of GRB 060418
  5. GRB(?)060421:MASTER optical limit
  6. GRB(?)060421 : XRT position
  7. Possible GRB060421: BART limits
  8. GRB(?) 060421: Swift detection of a burst
  9. Erratum of GCN 4983 for GRB 060418 IR follow-up
  10. GRB 060418 : IR afterglow observations
  11. GRB 060418 : Lulin Optical follow-up
  12. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  13. GRB 060418: Radio Observations
  14. GRB060418, BVRcIc field calibration
  15. GRB060418: Swift/UVOT Observations
  16. GRB060418: Optical Observations
  17. GRB 060418: FRAM early afterglow observation
  18. GRB 060418: Refined Analysis of the Swift-BAT burst
  19. VLT/UVES observations of GRB060418
  20. GRB060418: Swift XRT Team Refined Analysis
  21. GRB 060418, SMARTS continuing afterglow observations
  22. GRB 060418: PROMPT Detections
  23. GRB 060418, SMARTS optical/IR afterglow observations
  24. GRB060418: Magellan/MIKE Spectroscopic Redshift
  25. GRB060418 : LT optical afterglow observation
  26. GRB 060418: REM candidate afterglow
  27. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  28. SGR 1900+14: Refined analysis of the Swift-BAT outburst
  29. GRB060413: Swift/UVOT upper limits
  30. GRB 060413: REM NIR Observations
  31. SGR 1900+14: Swift detection of an outburst
  32. GRB 060413: Refined analysis of the Swift-BAT burst
  33. GRB 060413: Watcher UBVR observations
  34. GRB 060413: XRT refined analysis
  35. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  36. GRB 060413: Swift detection of a burst
  37. GRB060403: optical observations
  38. GRB 060403 Optical observations
  39. GRB 060403: MITSuME optical observation
  40. GRB060403: Optical Limit
  41. GRB060403: XRT refined analysis
  42. GRB 060403: Swift/UVOT upper limits
  43. HETE Triggers H4043 and H4044 Not Due to New Cosmic Source
  44. SGR 1900+14: BAT observations
  45. GRB 060403: Refined analysis of the Swift-BAT burst
  46. GRB060403: Swift XRT refined position
  47. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  48. GRB 060403: Swift detection of a burst
  49. HETE trigger H4044: RTT150 optical observations
  50. GRB060331: Swift/UVOT upper limits
  51. H4044, a Repeat Outburst From The Source of H4043 (="GRB060331")
  52. Swift XRT observations of the HETE transient H4043
  53. HETE Trigger 4043: ROTSE-III Optical Limits
  54. Correction to Circular 4938, =H4043, an unusual high energy transient observed by HETE
  55. H4043, an unusual high-energy transient observed by HETE
  56. GRB 060322: LNA optical limit
  57. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  58. INTEGRAL and XMM ToO observations of SGR1900+14
  59. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  60. SGR 1900+14: Swift-BAT detection of a bright outburst
  61. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  62. GRB 060323 : WIDGET simultaneous optical observations
  63. GRB 060323: Early optical observation at Xinglong
  64. GRB060218, optical observations
  65. GRB 060322: Confirmation of Swift XRT afterglow
  66. GRB 060211A: optical observation
  67. GRB060323: optical limit
  68. GRB060211B: optical observation
  69. SGR 1900+14: CORRECTION to GCN 4923
  70. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  71. SGR 1900+14: Swift detection of renewed activity
  72. GRB060323: NOT optical observations
  73. GRB 060322: IAC80 optical observations
  74. GRB 060322: Swift XRT afterglow candidate
  75. GRB060323: P60 Observations
  76. GRB 060323: Swift/UVOT Observations
  77. GRB 060323: optical afterglow confirmed
  78. GRB060323: NOT observations
  79. GRB 060323: Optical Observations
  80. GRB 060323: Tautenburg OT candidate retraction
  81. GRB 060323: Refined analysis of the Swift-BAT burst
  82. GRB 060323: optical observations at TNG
  83. GRB 060323: Swift XRT refined analysis
  84. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  85. GRB 060323: Swift/XRT position
  86. GRB 060322: Refined analysis of the Swift-BAT burst
  87. GRB060323, optical observation
  88. GRB060323 - SDSS Pre-Burst Observations
  89. GRB 060323: Swift detection of a burst with a possible optical afterglow
  90. GRB 060322: Swift-BAT detection of a 200-sec burst
  91. GRB060219: optical observation
  92. GRB060206: optical observation
  93. GRB060218/SN2006aj: optical observations
  94. GRB 060218/SN 2006aj, LNA optical observation
  95. GRB060218: Refined photometric calibration of comparison stars
  96. GRB 060319: WHT K-band candidate afterglow
  97. GRB 060319: IAC-80 optical observations
  98. GRB060319: Swift XRT refined analysis
  99. GRB060319: Swift/UVOT upper limits
  100. GRB 060319: Re-analysis of TNG data

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