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

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