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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 060306: Swift-XRT team refined analysis
  2. GRB 060306: PROMPT Observations
  3. GRB 060306: Swift detection of a bright burst
  4. GRB 060218: RTT150 optical observations
  5. GRB060218: Ep,i - Eiso correlation
  6. GRB060218: R-band CCD photmetry
  7. GRB060223b: optical limit
  8. GRB060218/SN 2006aj: optical observation in V
  9. GRB060218/SN 2006aj: optical observation
  10. GRB 060121: HST observations
  11. GRB 060218 : GMRT observation [Correction and Improvement]
  12. GRB 060223b: Swift/UVOT Upper Limits
  13. GRB 060218/SN 2006aj: K-380 optical observations
  14. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  15. GRB200618: optical polarimetry and photometry
  16. GRB 060223B: Swift XRT possible afterglow
  17. GRB 060218/SN 2006aj: ABT observations
  18. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  19. GRB 060218 : Radio upper limits from GMRT
  20. GRB 060218/SN 2006aj: WIRO optical observations
  21. GRB 060218/SN 2006aj: RBO optical observations
  22. GRB 060204B: GETS early limit
  23. GRB 060218: Refined analysis of the radio afterglow
  24. GRB 060223A:Xinglong optical limits
  25. GRB 060223B: ART optical limits
  26. GRB 060223B: Swift-BAT refined analysis
  27. GRB 060223a: Swift/UVOT refined analysis
  28. GRB 060223: Swift XRT Team preliminary analysis
  29. GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux
  30. GRB 060223B: Swift detection of a bright burst
  31. GRB 060223: Swift-BAT refined analysis
  32. GRB 060218: rebrightening
  33. Correction to GCN 4816 on GRB060218
  34. GRB 060218/SN 2006aj: optical observations
  35. GRB060218: Optical brightening in V and R
  36. GRB 060223: Keck redshift
  37. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  38. GRB 060223: Swift detection of a burst
  39. Spectral properties of GRB060218/SN2006aj
  40. GRB 060219: Swift-BAT refined analysis
  41. GRB 060218: rebrightening
  42. GRB 060218: emergence of the underlying SN spectrum
  43. GRB 060218: Decline in r-band flux
  44. GRB 060218: spectroscopic observations
  45. GRB 060218: Further refined analysis of the Swift-BAT burst
  46. GRB 060218: Likely an underluminous GRB
  47. GRB060218: Optical Spectroscopy of GRB-SN
  48. GRB060218: VLT spectroscopy
  49. GRB 060218: Optical Observations at Xinglong Obs.
  50. GRB 060219: SDSS galaxy inside XRT error circle
  51. GRB060218: UV Detection and Light Curves
  52. GRB060219: SARA Observations
  53. GRB 060219: Swift/UVOT Upper Limits
  54. GRB 060219: Swift-XRT Team refined analysis
  55. GRB 051221B: Swift-XRT Team Refined Analysis
  56. GRB 060219: Partial refined analysis of the Swift-BAT burst
  57. GRB060218: Radio Afterglow Discovery
  58. GRB 060219: Swift-XRT position typo correction
  59. GRB 060218: MDM Redshift
  60. GRB 060219: Swift-XRT position
  61. GRB 060218: optical/nIR observations at La Palma
  62. GRB060219: SDSS pre-burst observations
  63. GRB 060219: Swift-BAT detection of a weak burst
  64. Oddball GRB 060218, transient or GRB?
  65. GRB060218: Swift/XRT Team preliminary analysis of the possible burst
  66. Brightening of the Optical Counterpart of the Possible GRB 060218
  67. GRB 060218: MDM Observations
  68. GRB 060218: Pre-burst detection of a possible host galaxy
  69. GRB 060218A: ROTSE-III Possible Optical Flare
  70. GRB060218: Swift/XRT refined position of a possible burst
  71. Preliminary refined analysis of the Swift-BAT trigger 191157
  72. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  73. GRB 060211B: Swift/UVOT Upper Limits
  74. GRB060218 : SDSS pre-burst observations
  75. GRB 060218: Swift XRT Position
  76. GRB 060218: Swift-BAT detection of a possible burst
  77. GRB 060213: optical afterglow not confirmed
  78. Swift UVOT observations of GRB060213
  79. GRB 060211B: Skynet Observations
  80. GRB 060213: optical afterglow candidate
  81. GRB060213: Swift XRT observations and possible afterglow candidate
  82. GRB 060213: pseudo-z = 3.5 +/- 0.35 from spectral parameters
  83. GRB 060206: Confirmation of Rapid Fading at Optical Wavelengths
  84. GRB060213: MASTER final result
  85. GRB 060211b: WIRO NIR Observations
  86. GRB060213:_MASTER_optical_observation
  87. GRB060206: Swift XRT observations of an unbroken powerlaw decay
  88. Konus-Wind observation of bright hard GRB 060213
  89. GRB 060213: IPN localization
  90. GRB 060210: Radio Observations
  91. GRB 060211a: WIRO NIR Observations
  92. GRB060211B: REM optical and NIR observations
  93. GRB 060211B: BAT detects no additional burst emission beyond T + 122 sec
  94. GRB 060211A: Further refined analysis of the Swift burst
  95. GRB060121: optical observations
  96. GRB060110: optical observations
  97. GRB060105: optical observations
  98. GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
  99. GRB 060211b: P60 Observations
  100. GRB 060211A: Partial refined analysis on the Swift-BAT burst

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