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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 060313, SMARTS optical counterpart?
  2. GRB 060313: Possible optical counterpart
  3. GRB 060313: Swift XRT position
  4. GRB 060313, SMARTS optical/IR observations
  5. GRB060313: optical and near infrared observations with REM
  6. GRB 060313: Swift-BAT detection of a bright short hard burst
  7. GRB060218: SARA Observations of SN2006aj
  8. GRB060312: Swift UVOT observation
  9. GRB 060312: Refined analysis of the Swift-BAT burst
  10. GRB 060218/SN 2006aj, high resolution spectra
  11. GRB 060312: Swift XRT team refined analysis
  12. GRB060306: APO Ks-band Imaging Observations
  13. GRB 060312: ROTSE-III Optical Limits
  14. GRB 060312: Swift detection of a burst
  15. IBAS Alert n. 3218 : not a real GRB
  16. GRB 060306: SOAR Ks Observations
  17. Bright short hard GRB 060303: IPN localization and Konus spectrum
  18. GRB060219: Liverpool Telescope observations
  19. GRB 060306: MAGNUM observations
  20. GRB060218: analysis of the XMM-Newton observation
  21. Swift/UVOT observations of GRB060306
  22. GRB 060306: Swift-BAT refined analysis
  23. GRB 060306: Swift-XRT team refined analysis
  24. GRB 060306: PROMPT Observations
  25. GRB 060306: Swift detection of a bright burst
  26. GRB 060218: RTT150 optical observations
  27. GRB060218: Ep,i - Eiso correlation
  28. GRB060218: R-band CCD photmetry
  29. GRB060223b: optical limit
  30. GRB060218/SN 2006aj: optical observation in V
  31. GRB060218/SN 2006aj: optical observation
  32. GRB 060121: HST observations
  33. GRB 060218 : GMRT observation [Correction and Improvement]
  34. GRB 060223b: Swift/UVOT Upper Limits
  35. GRB 060218/SN 2006aj: K-380 optical observations
  36. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  37. GRB200618: optical polarimetry and photometry
  38. GRB 060223B: Swift XRT possible afterglow
  39. GRB 060218/SN 2006aj: ABT observations
  40. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  41. GRB 060218 : Radio upper limits from GMRT
  42. GRB 060218/SN 2006aj: WIRO optical observations
  43. GRB 060218/SN 2006aj: RBO optical observations
  44. GRB 060204B: GETS early limit
  45. GRB 060218: Refined analysis of the radio afterglow
  46. GRB 060223A:Xinglong optical limits
  47. GRB 060223B: ART optical limits
  48. GRB 060223B: Swift-BAT refined analysis
  49. GRB 060223a: Swift/UVOT refined analysis
  50. GRB 060223: Swift XRT Team preliminary analysis
  51. GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux
  52. GRB 060223B: Swift detection of a bright burst
  53. GRB 060223: Swift-BAT refined analysis
  54. GRB 060218: rebrightening
  55. Correction to GCN 4816 on GRB060218
  56. GRB 060218/SN 2006aj: optical observations
  57. GRB060218: Optical brightening in V and R
  58. GRB 060223: Keck redshift
  59. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  60. GRB 060223: Swift detection of a burst
  61. Spectral properties of GRB060218/SN2006aj
  62. GRB 060219: Swift-BAT refined analysis
  63. GRB 060218: rebrightening
  64. GRB 060218: emergence of the underlying SN spectrum
  65. GRB 060218: Decline in r-band flux
  66. GRB 060218: spectroscopic observations
  67. GRB 060218: Further refined analysis of the Swift-BAT burst
  68. GRB 060218: Likely an underluminous GRB
  69. GRB060218: Optical Spectroscopy of GRB-SN
  70. GRB060218: VLT spectroscopy
  71. GRB 060218: Optical Observations at Xinglong Obs.
  72. GRB 060219: SDSS galaxy inside XRT error circle
  73. GRB060218: UV Detection and Light Curves
  74. GRB060219: SARA Observations
  75. GRB 060219: Swift/UVOT Upper Limits
  76. GRB 060219: Swift-XRT Team refined analysis
  77. GRB 051221B: Swift-XRT Team Refined Analysis
  78. GRB 060219: Partial refined analysis of the Swift-BAT burst
  79. GRB060218: Radio Afterglow Discovery
  80. GRB 060219: Swift-XRT position typo correction
  81. GRB 060218: MDM Redshift
  82. GRB 060219: Swift-XRT position
  83. GRB 060218: optical/nIR observations at La Palma
  84. GRB060219: SDSS pre-burst observations
  85. GRB 060219: Swift-BAT detection of a weak burst
  86. Oddball GRB 060218, transient or GRB?
  87. GRB060218: Swift/XRT Team preliminary analysis of the possible burst
  88. Brightening of the Optical Counterpart of the Possible GRB 060218
  89. GRB 060218: MDM Observations
  90. GRB 060218: Pre-burst detection of a possible host galaxy
  91. GRB 060218A: ROTSE-III Possible Optical Flare
  92. GRB060218: Swift/XRT refined position of a possible burst
  93. Preliminary refined analysis of the Swift-BAT trigger 191157
  94. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  95. GRB 060211B: Swift/UVOT Upper Limits
  96. GRB060218 : SDSS pre-burst observations
  97. GRB 060218: Swift XRT Position
  98. GRB 060218: Swift-BAT detection of a possible burst
  99. GRB 060213: optical afterglow not confirmed
  100. Swift UVOT observations of GRB060213

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