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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. GRB060312: Swift UVOT observation
  2. GRB 060312: Refined analysis of the Swift-BAT burst
  3. GRB 060218/SN 2006aj, high resolution spectra
  4. GRB 060312: Swift XRT team refined analysis
  5. GRB060306: APO Ks-band Imaging Observations
  6. GRB 060312: ROTSE-III Optical Limits
  7. GRB 060312: Swift detection of a burst
  8. IBAS Alert n. 3218 : not a real GRB
  9. GRB 060306: SOAR Ks Observations
  10. Bright short hard GRB 060303: IPN localization and Konus spectrum
  11. GRB060219: Liverpool Telescope observations
  12. GRB 060306: MAGNUM observations
  13. GRB060218: analysis of the XMM-Newton observation
  14. Swift/UVOT observations of GRB060306
  15. GRB 060306: Swift-BAT refined analysis
  16. GRB 060306: Swift-XRT team refined analysis
  17. GRB 060306: PROMPT Observations
  18. GRB 060306: Swift detection of a bright burst
  19. GRB 060218: RTT150 optical observations
  20. GRB060218: Ep,i - Eiso correlation
  21. GRB060218: R-band CCD photmetry
  22. GRB060223b: optical limit
  23. GRB060218/SN 2006aj: optical observation in V
  24. GRB060218/SN 2006aj: optical observation
  25. GRB 060121: HST observations
  26. GRB 060218 : GMRT observation [Correction and Improvement]
  27. GRB 060223b: Swift/UVOT Upper Limits
  28. GRB 060218/SN 2006aj: K-380 optical observations
  29. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  30. GRB200618: optical polarimetry and photometry
  31. GRB 060223B: Swift XRT possible afterglow
  32. GRB 060218/SN 2006aj: ABT observations
  33. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  34. GRB 060218 : Radio upper limits from GMRT
  35. GRB 060218/SN 2006aj: WIRO optical observations
  36. GRB 060218/SN 2006aj: RBO optical observations
  37. GRB 060204B: GETS early limit
  38. GRB 060218: Refined analysis of the radio afterglow
  39. GRB 060223A:Xinglong optical limits
  40. GRB 060223B: ART optical limits
  41. GRB 060223B: Swift-BAT refined analysis
  42. GRB 060223a: Swift/UVOT refined analysis
  43. GRB 060223: Swift XRT Team preliminary analysis
  44. GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux
  45. GRB 060223B: Swift detection of a bright burst
  46. GRB 060223: Swift-BAT refined analysis
  47. GRB 060218: rebrightening
  48. Correction to GCN 4816 on GRB060218
  49. GRB 060218/SN 2006aj: optical observations
  50. GRB060218: Optical brightening in V and R
  51. GRB 060223: Keck redshift
  52. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  53. GRB 060223: Swift detection of a burst
  54. Spectral properties of GRB060218/SN2006aj
  55. GRB 060219: Swift-BAT refined analysis
  56. GRB 060218: rebrightening
  57. GRB 060218: emergence of the underlying SN spectrum
  58. GRB 060218: Decline in r-band flux
  59. GRB 060218: spectroscopic observations
  60. GRB 060218: Further refined analysis of the Swift-BAT burst
  61. GRB 060218: Likely an underluminous GRB
  62. GRB060218: Optical Spectroscopy of GRB-SN
  63. GRB060218: VLT spectroscopy
  64. GRB 060218: Optical Observations at Xinglong Obs.
  65. GRB 060219: SDSS galaxy inside XRT error circle
  66. GRB060218: UV Detection and Light Curves
  67. GRB060219: SARA Observations
  68. GRB 060219: Swift/UVOT Upper Limits
  69. GRB 060219: Swift-XRT Team refined analysis
  70. GRB 051221B: Swift-XRT Team Refined Analysis
  71. GRB 060219: Partial refined analysis of the Swift-BAT burst
  72. GRB060218: Radio Afterglow Discovery
  73. GRB 060219: Swift-XRT position typo correction
  74. GRB 060218: MDM Redshift
  75. GRB 060219: Swift-XRT position
  76. GRB 060218: optical/nIR observations at La Palma
  77. GRB060219: SDSS pre-burst observations
  78. GRB 060219: Swift-BAT detection of a weak burst
  79. Oddball GRB 060218, transient or GRB?
  80. GRB060218: Swift/XRT Team preliminary analysis of the possible burst
  81. Brightening of the Optical Counterpart of the Possible GRB 060218
  82. GRB 060218: MDM Observations
  83. GRB 060218: Pre-burst detection of a possible host galaxy
  84. GRB 060218A: ROTSE-III Possible Optical Flare
  85. GRB060218: Swift/XRT refined position of a possible burst
  86. Preliminary refined analysis of the Swift-BAT trigger 191157
  87. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  88. GRB 060211B: Swift/UVOT Upper Limits
  89. GRB060218 : SDSS pre-burst observations
  90. GRB 060218: Swift XRT Position
  91. GRB 060218: Swift-BAT detection of a possible burst
  92. GRB 060213: optical afterglow not confirmed
  93. Swift UVOT observations of GRB060213
  94. GRB 060211B: Skynet Observations
  95. GRB 060213: optical afterglow candidate
  96. GRB060213: Swift XRT observations and possible afterglow candidate
  97. GRB 060213: pseudo-z = 3.5 +/- 0.35 from spectral parameters
  98. GRB 060206: Confirmation of Rapid Fading at Optical Wavelengths
  99. GRB060213: MASTER final result
  100. GRB 060211b: WIRO NIR Observations

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