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

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