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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. GRB060211B: optical observation
  2. SGR 1900+14: CORRECTION to GCN 4923
  3. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  4. SGR 1900+14: Swift detection of renewed activity
  5. GRB060323: NOT optical observations
  6. GRB 060322: IAC80 optical observations
  7. GRB 060322: Swift XRT afterglow candidate
  8. GRB060323: P60 Observations
  9. GRB 060323: Swift/UVOT Observations
  10. GRB 060323: optical afterglow confirmed
  11. GRB060323: NOT observations
  12. GRB 060323: Optical Observations
  13. GRB 060323: Tautenburg OT candidate retraction
  14. GRB 060323: Refined analysis of the Swift-BAT burst
  15. GRB 060323: optical observations at TNG
  16. GRB 060323: Swift XRT refined analysis
  17. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  18. GRB 060323: Swift/XRT position
  19. GRB 060322: Refined analysis of the Swift-BAT burst
  20. GRB060323, optical observation
  21. GRB060323 - SDSS Pre-Burst Observations
  22. GRB 060323: Swift detection of a burst with a possible optical afterglow
  23. GRB 060322: Swift-BAT detection of a 200-sec burst
  24. GRB060219: optical observation
  25. GRB060206: optical observation
  26. GRB060218/SN2006aj: optical observations
  27. GRB 060218/SN 2006aj, LNA optical observation
  28. GRB060218: Refined photometric calibration of comparison stars
  29. GRB 060319: WHT K-band candidate afterglow
  30. GRB 060319: IAC-80 optical observations
  31. GRB060319: Swift XRT refined analysis
  32. GRB060319: Swift/UVOT upper limits
  33. GRB 060319: Re-analysis of TNG data
  34. GRB060319: MASTER limit
  35. GRB 060319: Swift-BAT refined analysis
  36. GRB 060319 optical observations at TNG
  37. GRB060319 : Liverpool Telescope optical limit
  38. GRB060319: MASTER optical observation
  39. GRB060319 - SDSS Pre-burst Observations
  40. GRB060319: Swift/XRT position
  41. GRB 060319: Swift detection of a burst
  42. GRB060313: Radio Observations
  43. GRB 060313: early afterglow NIR upper limits with REM
  44. IBAS Alert n. 3221: not a GRB
  45. Konus-Wind observation of GRB 060313
  46. GRB060313: SSO 40inch Observations
  47. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  48. GRB 060313: PROMPT Observations
  49. GRB 060313: Swift/UVOT Observations
  50. GRB060313:Gemini South Observations
  51. GRB 060313: Swift-XRT team refined analysis
  52. GRB060313: optical observations of the afterglow candidate
  53. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  54. GRB 060313, SMARTS optical counterpart?
  55. GRB 060313: Possible optical counterpart
  56. GRB 060313: Swift XRT position
  57. GRB 060313, SMARTS optical/IR observations
  58. GRB060313: optical and near infrared observations with REM
  59. GRB 060313: Swift-BAT detection of a bright short hard burst
  60. GRB060218: SARA Observations of SN2006aj
  61. GRB060312: Swift UVOT observation
  62. GRB 060312: Refined analysis of the Swift-BAT burst
  63. GRB 060218/SN 2006aj, high resolution spectra
  64. GRB 060312: Swift XRT team refined analysis
  65. GRB060306: APO Ks-band Imaging Observations
  66. GRB 060312: ROTSE-III Optical Limits
  67. GRB 060312: Swift detection of a burst
  68. IBAS Alert n. 3218 : not a real GRB
  69. GRB 060306: SOAR Ks Observations
  70. Bright short hard GRB 060303: IPN localization and Konus spectrum
  71. GRB060219: Liverpool Telescope observations
  72. GRB 060306: MAGNUM observations
  73. GRB060218: analysis of the XMM-Newton observation
  74. Swift/UVOT observations of GRB060306
  75. GRB 060306: Swift-BAT refined analysis
  76. GRB 060306: Swift-XRT team refined analysis
  77. GRB 060306: PROMPT Observations
  78. GRB 060306: Swift detection of a bright burst
  79. GRB 060218: RTT150 optical observations
  80. GRB060218: Ep,i - Eiso correlation
  81. GRB060218: R-band CCD photmetry
  82. GRB060223b: optical limit
  83. GRB060218/SN 2006aj: optical observation in V
  84. GRB060218/SN 2006aj: optical observation
  85. GRB 060121: HST observations
  86. GRB 060218 : GMRT observation [Correction and Improvement]
  87. GRB 060223b: Swift/UVOT Upper Limits
  88. GRB 060218/SN 2006aj: K-380 optical observations
  89. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  90. GRB200618: optical polarimetry and photometry
  91. GRB 060223B: Swift XRT possible afterglow
  92. GRB 060218/SN 2006aj: ABT observations
  93. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  94. GRB 060218 : Radio upper limits from GMRT
  95. GRB 060218/SN 2006aj: WIRO optical observations
  96. GRB 060218/SN 2006aj: RBO optical observations
  97. GRB 060204B: GETS early limit
  98. GRB 060218: Refined analysis of the radio afterglow
  99. GRB 060223A:Xinglong optical limits
  100. GRB 060223B: ART optical limits

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