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

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