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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"

26042 results found.

  1. VLT/UVES observations of GRB060418
  2. GRB060418: Swift XRT Team Refined Analysis
  3. GRB 060418, SMARTS continuing afterglow observations
  4. GRB 060418: PROMPT Detections
  5. GRB 060418, SMARTS optical/IR afterglow observations
  6. GRB060418: Magellan/MIKE Spectroscopic Redshift
  7. GRB060418 : LT optical afterglow observation
  8. GRB 060418: REM candidate afterglow
  9. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  10. SGR 1900+14: Refined analysis of the Swift-BAT outburst
  11. GRB060413: Swift/UVOT upper limits
  12. GRB 060413: REM NIR Observations
  13. SGR 1900+14: Swift detection of an outburst
  14. GRB 060413: Refined analysis of the Swift-BAT burst
  15. GRB 060413: Watcher UBVR observations
  16. GRB 060413: XRT refined analysis
  17. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  18. GRB 060413: Swift detection of a burst
  19. GRB060403: optical observations
  20. GRB 060403 Optical observations
  21. GRB 060403: MITSuME optical observation
  22. GRB060403: Optical Limit
  23. GRB060403: XRT refined analysis
  24. GRB 060403: Swift/UVOT upper limits
  25. SGR 1900+14: BAT observations
  26. GRB 060403: Refined analysis of the Swift-BAT burst
  27. GRB060403: Swift XRT refined position
  28. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  29. GRB 060403: Swift detection of a burst
  30. GRB060331: Swift/UVOT upper limits
  31. Swift XRT observations of the HETE transient H4043
  32. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  33. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  34. SGR 1900+14: Swift-BAT detection of a bright outburst
  35. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  36. GRB 060323 : WIDGET simultaneous optical observations
  37. GRB 060322: Confirmation of Swift XRT afterglow
  38. GRB 060211A: optical observation
  39. GRB060323: optical limit
  40. GRB060211B: optical observation
  41. SGR 1900+14: CORRECTION to GCN 4923
  42. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  43. SGR 1900+14: Swift detection of renewed activity
  44. GRB060323: NOT optical observations
  45. GRB 060322: IAC80 optical observations
  46. GRB 060322: Swift XRT afterglow candidate
  47. GRB060323: P60 Observations
  48. GRB 060323: Swift/UVOT Observations
  49. GRB 060323: optical afterglow confirmed
  50. GRB060323: NOT observations
  51. GRB 060323: Optical Observations
  52. GRB 060323: Tautenburg OT candidate retraction
  53. GRB 060323: Refined analysis of the Swift-BAT burst
  54. GRB 060323: optical observations at TNG
  55. GRB 060323: Swift XRT refined analysis
  56. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  57. GRB 060323: Swift/XRT position
  58. GRB 060322: Refined analysis of the Swift-BAT burst
  59. GRB060323 - SDSS Pre-Burst Observations
  60. GRB 060323: Swift detection of a burst with a possible optical afterglow
  61. GRB 060322: Swift-BAT detection of a 200-sec burst
  62. GRB060219: optical observation
  63. GRB060206: optical observation
  64. GRB 060319: WHT K-band candidate afterglow
  65. GRB 060319: IAC-80 optical observations
  66. GRB060319: Swift XRT refined analysis
  67. GRB060319: Swift/UVOT upper limits
  68. GRB060319: MASTER limit
  69. GRB 060319: Swift-BAT refined analysis
  70. GRB 060319 optical observations at TNG
  71. GRB060319 : Liverpool Telescope optical limit
  72. GRB060319: Swift/XRT position
  73. GRB 060319: Swift detection of a burst
  74. GRB060313: Radio Observations
  75. GRB 060313: early afterglow NIR upper limits with REM
  76. Konus-Wind observation of GRB 060313
  77. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  78. GRB 060313: PROMPT Observations
  79. GRB 060313: Swift/UVOT Observations
  80. GRB 060313: Swift-XRT team refined analysis
  81. GRB060313: optical observations of the afterglow candidate
  82. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  83. GRB 060313, SMARTS optical counterpart?
  84. GRB 060313: Possible optical counterpart
  85. GRB 060313: Swift XRT position
  86. GRB060313: optical and near infrared observations with REM
  87. GRB 060313: Swift-BAT detection of a bright short hard burst
  88. GRB060312: Swift UVOT observation
  89. GRB 060312: Refined analysis of the Swift-BAT burst
  90. GRB 060312: Swift XRT team refined analysis
  91. GRB060306: APO Ks-band Imaging Observations
  92. GRB 060312: ROTSE-III Optical Limits
  93. GRB 060312: Swift detection of a burst
  94. GRB 060306: SOAR Ks Observations
  95. Bright short hard GRB 060303: IPN localization and Konus spectrum
  96. GRB060219: Liverpool Telescope observations
  97. GRB 060306: MAGNUM observations
  98. GRB060218: analysis of the XMM-Newton observation
  99. Swift/UVOT observations of GRB060306
  100. GRB 060306: Swift-BAT refined analysis

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