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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. GRB060319: Swift/UVOT upper limits
  2. GRB 060319: Re-analysis of TNG data
  3. GRB060319: MASTER limit
  4. GRB 060319: Swift-BAT refined analysis
  5. GRB 060319 optical observations at TNG
  6. GRB060319 : Liverpool Telescope optical limit
  7. GRB060319: MASTER optical observation
  8. GRB060319 - SDSS Pre-burst Observations
  9. GRB060319: Swift/XRT position
  10. GRB 060319: Swift detection of a burst
  11. GRB060313: Radio Observations
  12. GRB 060313: early afterglow NIR upper limits with REM
  13. IBAS Alert n. 3221: not a GRB
  14. Konus-Wind observation of GRB 060313
  15. GRB060313: SSO 40inch Observations
  16. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  17. GRB 060313: PROMPT Observations
  18. GRB 060313: Swift/UVOT Observations
  19. GRB060313:Gemini South Observations
  20. GRB 060313: Swift-XRT team refined analysis
  21. GRB060313: optical observations of the afterglow candidate
  22. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  23. GRB 060313, SMARTS optical counterpart?
  24. GRB 060313: Possible optical counterpart
  25. GRB 060313: Swift XRT position
  26. GRB 060313, SMARTS optical/IR observations
  27. GRB060313: optical and near infrared observations with REM
  28. GRB 060313: Swift-BAT detection of a bright short hard burst
  29. GRB060218: SARA Observations of SN2006aj
  30. GRB060312: Swift UVOT observation
  31. GRB 060312: Refined analysis of the Swift-BAT burst
  32. GRB 060218/SN 2006aj, high resolution spectra
  33. GRB 060312: Swift XRT team refined analysis
  34. GRB060306: APO Ks-band Imaging Observations
  35. GRB 060312: ROTSE-III Optical Limits
  36. GRB 060312: Swift detection of a burst
  37. IBAS Alert n. 3218 : not a real GRB
  38. GRB 060306: SOAR Ks Observations
  39. Bright short hard GRB 060303: IPN localization and Konus spectrum
  40. GRB060219: Liverpool Telescope observations
  41. GRB 060306: MAGNUM observations
  42. GRB060218: analysis of the XMM-Newton observation
  43. Swift/UVOT observations of GRB060306
  44. GRB 060306: Swift-BAT refined analysis
  45. GRB 060306: Swift-XRT team refined analysis
  46. GRB 060306: PROMPT Observations
  47. GRB 060306: Swift detection of a bright burst
  48. GRB 060218: RTT150 optical observations
  49. GRB060218: Ep,i - Eiso correlation
  50. GRB060218: R-band CCD photmetry
  51. GRB060223b: optical limit
  52. GRB060218/SN 2006aj: optical observation in V
  53. GRB060218/SN 2006aj: optical observation
  54. GRB 060121: HST observations
  55. GRB 060218 : GMRT observation [Correction and Improvement]
  56. GRB 060223b: Swift/UVOT Upper Limits
  57. GRB 060218/SN 2006aj: K-380 optical observations
  58. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  59. GRB200618: optical polarimetry and photometry
  60. GRB 060223B: Swift XRT possible afterglow
  61. GRB 060218/SN 2006aj: ABT observations
  62. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  63. GRB 060218 : Radio upper limits from GMRT
  64. GRB 060218/SN 2006aj: WIRO optical observations
  65. GRB 060218/SN 2006aj: RBO optical observations
  66. GRB 060204B: GETS early limit
  67. GRB 060218: Refined analysis of the radio afterglow
  68. GRB 060223A:Xinglong optical limits
  69. GRB 060223B: ART optical limits
  70. GRB 060223B: Swift-BAT refined analysis
  71. GRB 060223a: Swift/UVOT refined analysis
  72. GRB 060223: Swift XRT Team preliminary analysis
  73. GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux
  74. GRB 060223B: Swift detection of a bright burst
  75. GRB 060223: Swift-BAT refined analysis
  76. GRB 060218: rebrightening
  77. Correction to GCN 4816 on GRB060218
  78. GRB 060218/SN 2006aj: optical observations
  79. GRB060218: Optical brightening in V and R
  80. GRB 060223: Keck redshift
  81. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  82. GRB 060223: Swift detection of a burst
  83. Spectral properties of GRB060218/SN2006aj
  84. GRB 060219: Swift-BAT refined analysis
  85. GRB 060218: rebrightening
  86. GRB 060218: emergence of the underlying SN spectrum
  87. GRB 060218: Decline in r-band flux
  88. GRB 060218: spectroscopic observations
  89. GRB 060218: Further refined analysis of the Swift-BAT burst
  90. GRB 060218: Likely an underluminous GRB
  91. GRB060218: Optical Spectroscopy of GRB-SN
  92. GRB060218: VLT spectroscopy
  93. GRB 060218: Optical Observations at Xinglong Obs.
  94. GRB 060219: SDSS galaxy inside XRT error circle
  95. GRB060218: UV Detection and Light Curves
  96. GRB060219: SARA Observations
  97. GRB 060219: Swift/UVOT Upper Limits
  98. GRB 060219: Swift-XRT Team refined analysis
  99. GRB 051221B: Swift-XRT Team Refined Analysis
  100. GRB 060219: Partial refined analysis of the Swift-BAT burst

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