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

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