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

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