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

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