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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 060323: Swift/UVOT Observations
  2. GRB 060323: optical afterglow confirmed
  3. GRB060323: NOT observations
  4. GRB 060323: Optical Observations
  5. GRB 060323: Tautenburg OT candidate retraction
  6. GRB 060323: Refined analysis of the Swift-BAT burst
  7. GRB 060323: optical observations at TNG
  8. GRB 060323: Swift XRT refined analysis
  9. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  10. GRB 060323: Swift/XRT position
  11. GRB 060322: Refined analysis of the Swift-BAT burst
  12. GRB060323, optical observation
  13. GRB060323 - SDSS Pre-Burst Observations
  14. GRB 060323: Swift detection of a burst with a possible optical afterglow
  15. GRB 060322: Swift-BAT detection of a 200-sec burst
  16. GRB060219: optical observation
  17. GRB060206: optical observation
  18. GRB060218/SN2006aj: optical observations
  19. GRB 060218/SN 2006aj, LNA optical observation
  20. GRB060218: Refined photometric calibration of comparison stars
  21. GRB 060319: WHT K-band candidate afterglow
  22. GRB 060319: IAC-80 optical observations
  23. GRB060319: Swift XRT refined analysis
  24. GRB060319: Swift/UVOT upper limits
  25. GRB 060319: Re-analysis of TNG data
  26. GRB060319: MASTER limit
  27. GRB 060319: Swift-BAT refined analysis
  28. GRB 060319 optical observations at TNG
  29. GRB060319 : Liverpool Telescope optical limit
  30. GRB060319: MASTER optical observation
  31. GRB060319 - SDSS Pre-burst Observations
  32. GRB060319: Swift/XRT position
  33. GRB 060319: Swift detection of a burst
  34. GRB060313: Radio Observations
  35. GRB 060313: early afterglow NIR upper limits with REM
  36. IBAS Alert n. 3221: not a GRB
  37. Konus-Wind observation of GRB 060313
  38. GRB060313: SSO 40inch Observations
  39. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  40. GRB 060313: PROMPT Observations
  41. GRB 060313: Swift/UVOT Observations
  42. GRB060313:Gemini South Observations
  43. GRB 060313: Swift-XRT team refined analysis
  44. GRB060313: optical observations of the afterglow candidate
  45. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  46. GRB 060313, SMARTS optical counterpart?
  47. GRB 060313: Possible optical counterpart
  48. GRB 060313: Swift XRT position
  49. GRB 060313, SMARTS optical/IR observations
  50. GRB060313: optical and near infrared observations with REM
  51. GRB 060313: Swift-BAT detection of a bright short hard burst
  52. GRB060218: SARA Observations of SN2006aj
  53. GRB060312: Swift UVOT observation
  54. GRB 060312: Refined analysis of the Swift-BAT burst
  55. GRB 060218/SN 2006aj, high resolution spectra
  56. GRB 060312: Swift XRT team refined analysis
  57. GRB060306: APO Ks-band Imaging Observations
  58. GRB 060312: ROTSE-III Optical Limits
  59. GRB 060312: Swift detection of a burst
  60. IBAS Alert n. 3218 : not a real GRB
  61. GRB 060306: SOAR Ks Observations
  62. Bright short hard GRB 060303: IPN localization and Konus spectrum
  63. GRB060219: Liverpool Telescope observations
  64. GRB 060306: MAGNUM observations
  65. GRB060218: analysis of the XMM-Newton observation
  66. Swift/UVOT observations of GRB060306
  67. GRB 060306: Swift-BAT refined analysis
  68. GRB 060306: Swift-XRT team refined analysis
  69. GRB 060306: PROMPT Observations
  70. GRB 060306: Swift detection of a bright burst
  71. GRB 060218: RTT150 optical observations
  72. GRB060218: Ep,i - Eiso correlation
  73. GRB060218: R-band CCD photmetry
  74. GRB060223b: optical limit
  75. GRB060218/SN 2006aj: optical observation in V
  76. GRB060218/SN 2006aj: optical observation
  77. GRB 060121: HST observations
  78. GRB 060218 : GMRT observation [Correction and Improvement]
  79. GRB 060223b: Swift/UVOT Upper Limits
  80. GRB 060218/SN 2006aj: K-380 optical observations
  81. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  82. GRB200618: optical polarimetry and photometry
  83. GRB 060223B: Swift XRT possible afterglow
  84. GRB 060218/SN 2006aj: ABT observations
  85. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  86. GRB 060218 : Radio upper limits from GMRT
  87. GRB 060218/SN 2006aj: WIRO optical observations
  88. GRB 060218/SN 2006aj: RBO optical observations
  89. GRB 060204B: GETS early limit
  90. GRB 060218: Refined analysis of the radio afterglow
  91. GRB 060223A:Xinglong optical limits
  92. GRB 060223B: ART optical limits
  93. GRB 060223B: Swift-BAT refined analysis
  94. GRB 060223a: Swift/UVOT refined analysis
  95. GRB 060223: Swift XRT Team preliminary analysis
  96. GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux
  97. GRB 060223B: Swift detection of a bright burst
  98. GRB 060223: Swift-BAT refined analysis
  99. GRB 060218: rebrightening
  100. Correction to GCN 4816 on GRB060218

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