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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 060418 : Lulin Optical follow-up
  2. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  3. GRB 060418: Radio Observations
  4. GRB060418, BVRcIc field calibration
  5. GRB060418: Swift/UVOT Observations
  6. GRB060418: Optical Observations
  7. GRB 060418: FRAM early afterglow observation
  8. GRB 060418: Refined Analysis of the Swift-BAT burst
  9. VLT/UVES observations of GRB060418
  10. GRB060418: Swift XRT Team Refined Analysis
  11. GRB 060418, SMARTS continuing afterglow observations
  12. GRB 060418: PROMPT Detections
  13. GRB 060418, SMARTS optical/IR afterglow observations
  14. GRB060418: Magellan/MIKE Spectroscopic Redshift
  15. GRB060418 : LT optical afterglow observation
  16. GRB 060418: REM candidate afterglow
  17. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  18. SGR 1900+14: Refined analysis of the Swift-BAT outburst
  19. GRB060413: Swift/UVOT upper limits
  20. GRB 060413: REM NIR Observations
  21. SGR 1900+14: Swift detection of an outburst
  22. GRB 060413: Refined analysis of the Swift-BAT burst
  23. GRB 060413: Watcher UBVR observations
  24. GRB 060413: XRT refined analysis
  25. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  26. GRB 060413: Swift detection of a burst
  27. GRB060403: optical observations
  28. GRB 060403 Optical observations
  29. GRB 060403: MITSuME optical observation
  30. GRB060403: Optical Limit
  31. GRB060403: XRT refined analysis
  32. GRB 060403: Swift/UVOT upper limits
  33. HETE Triggers H4043 and H4044 Not Due to New Cosmic Source
  34. SGR 1900+14: BAT observations
  35. GRB 060403: Refined analysis of the Swift-BAT burst
  36. GRB060403: Swift XRT refined position
  37. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  38. GRB 060403: Swift detection of a burst
  39. HETE trigger H4044: RTT150 optical observations
  40. GRB060331: Swift/UVOT upper limits
  41. H4044, a Repeat Outburst From The Source of H4043 (="GRB060331")
  42. Swift XRT observations of the HETE transient H4043
  43. HETE Trigger 4043: ROTSE-III Optical Limits
  44. Correction to Circular 4938, =H4043, an unusual high energy transient observed by HETE
  45. H4043, an unusual high-energy transient observed by HETE
  46. GRB 060322: LNA optical limit
  47. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  48. INTEGRAL and XMM ToO observations of SGR1900+14
  49. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  50. SGR 1900+14: Swift-BAT detection of a bright outburst
  51. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  52. GRB 060323 : WIDGET simultaneous optical observations
  53. GRB 060323: Early optical observation at Xinglong
  54. GRB060218, optical observations
  55. GRB 060322: Confirmation of Swift XRT afterglow
  56. GRB 060211A: optical observation
  57. GRB060323: optical limit
  58. GRB060211B: optical observation
  59. SGR 1900+14: CORRECTION to GCN 4923
  60. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  61. SGR 1900+14: Swift detection of renewed activity
  62. GRB060323: NOT optical observations
  63. GRB 060322: IAC80 optical observations
  64. GRB 060322: Swift XRT afterglow candidate
  65. GRB060323: P60 Observations
  66. GRB 060323: Swift/UVOT Observations
  67. GRB 060323: optical afterglow confirmed
  68. GRB060323: NOT observations
  69. GRB 060323: Optical Observations
  70. GRB 060323: Tautenburg OT candidate retraction
  71. GRB 060323: Refined analysis of the Swift-BAT burst
  72. GRB 060323: optical observations at TNG
  73. GRB 060323: Swift XRT refined analysis
  74. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  75. GRB 060323: Swift/XRT position
  76. GRB 060322: Refined analysis of the Swift-BAT burst
  77. GRB060323, optical observation
  78. GRB060323 - SDSS Pre-Burst Observations
  79. GRB 060323: Swift detection of a burst with a possible optical afterglow
  80. GRB 060322: Swift-BAT detection of a 200-sec burst
  81. GRB060219: optical observation
  82. GRB060206: optical observation
  83. GRB060218/SN2006aj: optical observations
  84. GRB 060218/SN 2006aj, LNA optical observation
  85. GRB060218: Refined photometric calibration of comparison stars
  86. GRB 060319: WHT K-band candidate afterglow
  87. GRB 060319: IAC-80 optical observations
  88. GRB060319: Swift XRT refined analysis
  89. GRB060319: Swift/UVOT upper limits
  90. GRB 060319: Re-analysis of TNG data
  91. GRB060319: MASTER limit
  92. GRB 060319: Swift-BAT refined analysis
  93. GRB 060319 optical observations at TNG
  94. GRB060319 : Liverpool Telescope optical limit
  95. GRB060319: MASTER optical observation
  96. GRB060319 - SDSS Pre-burst Observations
  97. GRB060319: Swift/XRT position
  98. GRB 060319: Swift detection of a burst
  99. GRB060313: Radio Observations
  100. GRB 060313: early afterglow NIR upper limits with REM

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