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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"

35321 results found.

  1. GRB 060427: NOT observations
  2. GRB 060427: Swift/UVOT upper limits.
  3. GRB 060427: Refined analysis of the Swift-BAT burst
  4. GRB060418: Swift XRT Team Further Refined Analysis
  5. GRB060425:MASTER survey observations
  6. GRB 060427, optical observation
  7. GRB 060427: Swift detection of a burst
  8. GRB 060425: IPN localization and KW spectrum of a short, hard burst
  9. An interactive program for GRB pseudo-redshift computations
  10. GRB060424: optical afterglow detection
  11. GRB060418: Further Analysis of MIKE Spectroscopy
  12. GRB 060424: Refined analysis of the Swift-BAT burst
  13. GRB 060424: Swift detection of a burst
  14. GRB 060421: TTT Observations
  15. GRB 060421: Swift-BAT Refined Analysis
  16. GRB 060421: Swift-XRT refined analysis
  17. GRB 060418: prediction of t_break
  18. GRB060418: optical observations
  19. Konus-Wind observation of GRB 060418
  20. GRB(?)060421:MASTER optical limit
  21. GRB(?)060421 : XRT position
  22. GRB(?) 060421: Swift detection of a burst
  23. Erratum of GCN 4983 for GRB 060418 IR follow-up
  24. GRB 060418 : IR afterglow observations
  25. GRB 060418 : Lulin Optical follow-up
  26. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  27. GRB 060418: Radio Observations
  28. GRB060418, BVRcIc field calibration
  29. GRB060418: Optical Observations
  30. GRB 060418: FRAM early afterglow observation
  31. GRB 060418: Refined Analysis of the Swift-BAT burst
  32. GRB060418: Swift XRT Team Refined Analysis
  33. GRB 060418, SMARTS continuing afterglow observations
  34. GRB 060418: PROMPT Detections
  35. GRB 060418, SMARTS optical/IR afterglow observations
  36. GRB060418: Magellan/MIKE Spectroscopic Redshift
  37. GRB060418 : LT optical afterglow observation
  38. GRB 060418: REM candidate afterglow
  39. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  40. GRB 060413: REM NIR Observations
  41. GRB 060413: Refined analysis of the Swift-BAT burst
  42. GRB 060413: Watcher UBVR observations
  43. GRB 060413: XRT refined analysis
  44. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  45. GRB 060413: Swift detection of a burst
  46. GRB060403: optical observations
  47. GRB 060403 Optical observations
  48. GRB 060403: MITSuME optical observation
  49. GRB060403: XRT refined analysis
  50. GRB 060403: Swift/UVOT upper limits
  51. GRB 060403: Refined analysis of the Swift-BAT burst
  52. GRB 060403: Swift detection of a burst
  53. GRB 060322: LNA optical limit
  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. GRB060323: NOT optical observations
  63. GRB 060322: IAC80 optical observations
  64. GRB 060322: Swift XRT afterglow candidate
  65. GRB 060323: Swift/UVOT Observations
  66. GRB 060323: optical afterglow confirmed
  67. GRB060323: NOT observations
  68. GRB 060323: Optical Observations
  69. GRB 060323: Tautenburg OT candidate retraction
  70. GRB 060323: Refined analysis of the Swift-BAT burst
  71. GRB 060323: optical observations at TNG
  72. GRB 060323: Swift XRT refined analysis
  73. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  74. GRB 060323: Swift/XRT position
  75. GRB 060322: Refined analysis of the Swift-BAT burst
  76. GRB060323 - SDSS Pre-Burst Observations
  77. GRB 060323: Swift detection of a burst with a possible optical afterglow
  78. GRB 060322: Swift-BAT detection of a 200-sec burst
  79. GRB060219: optical observation
  80. GRB060206: optical observation
  81. GRB060218/SN2006aj: optical observations
  82. GRB 060218/SN 2006aj, LNA optical observation
  83. GRB060218: Refined photometric calibration of comparison stars
  84. GRB 060319: WHT K-band candidate afterglow
  85. GRB 060319: IAC-80 optical observations
  86. GRB060319: Swift XRT refined analysis
  87. GRB 060319: Re-analysis of TNG data
  88. GRB060319: MASTER limit
  89. GRB 060319: Swift-BAT refined analysis
  90. GRB 060319 optical observations at TNG
  91. GRB060319 : Liverpool Telescope optical limit
  92. GRB060319: MASTER optical observation
  93. GRB060319 - SDSS Pre-burst Observations
  94. GRB 060319: Swift detection of a burst
  95. GRB060313: Radio Observations
  96. GRB 060313: early afterglow NIR upper limits with REM
  97. IBAS Alert n. 3221: not a GRB
  98. Konus-Wind observation of GRB 060313
  99. GRB060313: SSO 40inch Observations
  100. GRB 060313: Further analysis of the Swift-BAT bright short hard burst

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