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

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