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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 060312: Refined analysis of the Swift-BAT burst
  2. GRB 060218/SN 2006aj, high resolution spectra
  3. GRB 060312: Swift XRT team refined analysis
  4. GRB060306: APO Ks-band Imaging Observations
  5. GRB 060312: ROTSE-III Optical Limits
  6. GRB 060312: Swift detection of a burst
  7. IBAS Alert n. 3218 : not a real GRB
  8. GRB 060306: SOAR Ks Observations
  9. Bright short hard GRB 060303: IPN localization and Konus spectrum
  10. GRB060219: Liverpool Telescope observations
  11. GRB 060306: MAGNUM observations
  12. GRB060218: analysis of the XMM-Newton observation
  13. Swift/UVOT observations of GRB060306
  14. GRB 060306: Swift-BAT refined analysis
  15. GRB 060306: Swift-XRT team refined analysis
  16. GRB 060306: PROMPT Observations
  17. GRB 060306: Swift detection of a bright burst
  18. GRB 060218: RTT150 optical observations
  19. GRB060218: Ep,i - Eiso correlation
  20. GRB060218: R-band CCD photmetry
  21. GRB060223b: optical limit
  22. GRB060218/SN 2006aj: optical observation in V
  23. GRB060218/SN 2006aj: optical observation
  24. GRB 060121: HST observations
  25. GRB 060218 : GMRT observation [Correction and Improvement]
  26. GRB 060223b: Swift/UVOT Upper Limits
  27. GRB 060218/SN 2006aj: K-380 optical observations
  28. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  29. GRB200618: optical polarimetry and photometry
  30. GRB 060223B: Swift XRT possible afterglow
  31. GRB 060218/SN 2006aj: ABT observations
  32. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  33. GRB 060218 : Radio upper limits from GMRT
  34. GRB 060218/SN 2006aj: WIRO optical observations
  35. GRB 060218/SN 2006aj: RBO optical observations
  36. GRB 060204B: GETS early limit
  37. GRB 060218: Refined analysis of the radio afterglow
  38. GRB 060223A:Xinglong optical limits
  39. GRB 060223B: ART optical limits
  40. GRB 060223B: Swift-BAT refined analysis
  41. GRB 060223a: Swift/UVOT refined analysis
  42. GRB 060223: Swift XRT Team preliminary analysis
  43. GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux
  44. GRB 060223B: Swift detection of a bright burst
  45. GRB 060223: Swift-BAT refined analysis
  46. GRB 060218: rebrightening
  47. Correction to GCN 4816 on GRB060218
  48. GRB 060218/SN 2006aj: optical observations
  49. GRB060218: Optical brightening in V and R
  50. GRB 060223: Keck redshift
  51. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  52. GRB 060223: Swift detection of a burst
  53. Spectral properties of GRB060218/SN2006aj
  54. GRB 060219: Swift-BAT refined analysis
  55. GRB 060218: rebrightening
  56. GRB 060218: emergence of the underlying SN spectrum
  57. GRB 060218: Decline in r-band flux
  58. GRB 060218: spectroscopic observations
  59. GRB 060218: Further refined analysis of the Swift-BAT burst
  60. GRB 060218: Likely an underluminous GRB
  61. GRB060218: Optical Spectroscopy of GRB-SN
  62. GRB060218: VLT spectroscopy
  63. GRB 060218: Optical Observations at Xinglong Obs.
  64. GRB 060219: SDSS galaxy inside XRT error circle
  65. GRB060218: UV Detection and Light Curves
  66. GRB060219: SARA Observations
  67. GRB 060219: Swift/UVOT Upper Limits
  68. GRB 060219: Swift-XRT Team refined analysis
  69. GRB 051221B: Swift-XRT Team Refined Analysis
  70. GRB 060219: Partial refined analysis of the Swift-BAT burst
  71. GRB060218: Radio Afterglow Discovery
  72. GRB 060219: Swift-XRT position typo correction
  73. GRB 060218: MDM Redshift
  74. GRB 060219: Swift-XRT position
  75. GRB 060218: optical/nIR observations at La Palma
  76. GRB060219: SDSS pre-burst observations
  77. GRB 060219: Swift-BAT detection of a weak burst
  78. Oddball GRB 060218, transient or GRB?
  79. GRB060218: Swift/XRT Team preliminary analysis of the possible burst
  80. Brightening of the Optical Counterpart of the Possible GRB 060218
  81. GRB 060218: MDM Observations
  82. GRB 060218: Pre-burst detection of a possible host galaxy
  83. GRB 060218A: ROTSE-III Possible Optical Flare
  84. GRB060218: Swift/XRT refined position of a possible burst
  85. Preliminary refined analysis of the Swift-BAT trigger 191157
  86. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  87. GRB 060211B: Swift/UVOT Upper Limits
  88. GRB060218 : SDSS pre-burst observations
  89. GRB 060218: Swift XRT Position
  90. GRB 060218: Swift-BAT detection of a possible burst
  91. GRB 060213: optical afterglow not confirmed
  92. Swift UVOT observations of GRB060213
  93. GRB 060211B: Skynet Observations
  94. GRB 060213: optical afterglow candidate
  95. GRB060213: Swift XRT observations and possible afterglow candidate
  96. GRB 060213: pseudo-z = 3.5 +/- 0.35 from spectral parameters
  97. GRB 060206: Confirmation of Rapid Fading at Optical Wavelengths
  98. GRB060213: MASTER final result
  99. GRB 060211b: WIRO NIR Observations
  100. GRB060213:_MASTER_optical_observation

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