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

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