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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 060319: WHT K-band candidate afterglow
  2. GRB 060319: IAC-80 optical observations
  3. GRB060319: Swift XRT refined analysis
  4. GRB060319: Swift/UVOT upper limits
  5. GRB 060319: Re-analysis of TNG data
  6. GRB060319: MASTER limit
  7. GRB 060319: Swift-BAT refined analysis
  8. GRB 060319 optical observations at TNG
  9. GRB060319 : Liverpool Telescope optical limit
  10. GRB060319: MASTER optical observation
  11. GRB060319 - SDSS Pre-burst Observations
  12. GRB060319: Swift/XRT position
  13. GRB 060319: Swift detection of a burst
  14. GRB060313: Radio Observations
  15. GRB 060313: early afterglow NIR upper limits with REM
  16. IBAS Alert n. 3221: not a GRB
  17. Konus-Wind observation of GRB 060313
  18. GRB060313: SSO 40inch Observations
  19. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  20. GRB 060313: PROMPT Observations
  21. GRB 060313: Swift/UVOT Observations
  22. GRB060313:Gemini South Observations
  23. GRB 060313: Swift-XRT team refined analysis
  24. GRB060313: optical observations of the afterglow candidate
  25. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  26. GRB 060313, SMARTS optical counterpart?
  27. GRB 060313: Possible optical counterpart
  28. GRB 060313: Swift XRT position
  29. GRB 060313, SMARTS optical/IR observations
  30. GRB060313: optical and near infrared observations with REM
  31. GRB 060313: Swift-BAT detection of a bright short hard burst
  32. GRB060218: SARA Observations of SN2006aj
  33. GRB060312: Swift UVOT observation
  34. GRB 060312: Refined analysis of the Swift-BAT burst
  35. GRB 060218/SN 2006aj, high resolution spectra
  36. GRB 060312: Swift XRT team refined analysis
  37. GRB060306: APO Ks-band Imaging Observations
  38. GRB 060312: ROTSE-III Optical Limits
  39. GRB 060312: Swift detection of a burst
  40. IBAS Alert n. 3218 : not a real GRB
  41. GRB 060306: SOAR Ks Observations
  42. Bright short hard GRB 060303: IPN localization and Konus spectrum
  43. GRB060219: Liverpool Telescope observations
  44. GRB 060306: MAGNUM observations
  45. GRB060218: analysis of the XMM-Newton observation
  46. Swift/UVOT observations of GRB060306
  47. GRB 060306: Swift-BAT refined analysis
  48. GRB 060306: Swift-XRT team refined analysis
  49. GRB 060306: PROMPT Observations
  50. GRB 060306: Swift detection of a bright burst
  51. GRB 060218: RTT150 optical observations
  52. GRB060218: Ep,i - Eiso correlation
  53. GRB060218: R-band CCD photmetry
  54. GRB060223b: optical limit
  55. GRB060218/SN 2006aj: optical observation in V
  56. GRB060218/SN 2006aj: optical observation
  57. GRB 060121: HST observations
  58. GRB 060218 : GMRT observation [Correction and Improvement]
  59. GRB 060223b: Swift/UVOT Upper Limits
  60. GRB 060218/SN 2006aj: K-380 optical observations
  61. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  62. GRB200618: optical polarimetry and photometry
  63. GRB 060223B: Swift XRT possible afterglow
  64. GRB 060218/SN 2006aj: ABT observations
  65. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  66. GRB 060218 : Radio upper limits from GMRT
  67. GRB 060218/SN 2006aj: WIRO optical observations
  68. GRB 060218/SN 2006aj: RBO optical observations
  69. GRB 060204B: GETS early limit
  70. GRB 060218: Refined analysis of the radio afterglow
  71. GRB 060223A:Xinglong optical limits
  72. GRB 060223B: ART optical limits
  73. GRB 060223B: Swift-BAT refined analysis
  74. GRB 060223a: Swift/UVOT refined analysis
  75. GRB 060223: Swift XRT Team preliminary analysis
  76. GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux
  77. GRB 060223B: Swift detection of a bright burst
  78. GRB 060223: Swift-BAT refined analysis
  79. GRB 060218: rebrightening
  80. Correction to GCN 4816 on GRB060218
  81. GRB 060218/SN 2006aj: optical observations
  82. GRB060218: Optical brightening in V and R
  83. GRB 060223: Keck redshift
  84. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  85. GRB 060223: Swift detection of a burst
  86. Spectral properties of GRB060218/SN2006aj
  87. GRB 060219: Swift-BAT refined analysis
  88. GRB 060218: rebrightening
  89. GRB 060218: emergence of the underlying SN spectrum
  90. GRB 060218: Decline in r-band flux
  91. GRB 060218: spectroscopic observations
  92. GRB 060218: Further refined analysis of the Swift-BAT burst
  93. GRB 060218: Likely an underluminous GRB
  94. GRB060218: Optical Spectroscopy of GRB-SN
  95. GRB060218: VLT spectroscopy
  96. GRB 060218: Optical Observations at Xinglong Obs.
  97. GRB 060219: SDSS galaxy inside XRT error circle
  98. GRB060218: UV Detection and Light Curves
  99. GRB060219: SARA Observations
  100. GRB 060219: Swift/UVOT Upper Limits

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