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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. GRB060218/SN 2006aj: optical observation
  2. GRB 060121: HST observations
  3. GRB 060218 : GMRT observation [Correction and Improvement]
  4. GRB 060223b: Swift/UVOT Upper Limits
  5. GRB 060218/SN 2006aj: K-380 optical observations
  6. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  7. GRB200618: optical polarimetry and photometry
  8. GRB 060223B: Swift XRT possible afterglow
  9. GRB 060218/SN 2006aj: ABT observations
  10. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  11. GRB 060218 : Radio upper limits from GMRT
  12. GRB 060218/SN 2006aj: WIRO optical observations
  13. GRB 060218/SN 2006aj: RBO optical observations
  14. GRB 060204B: GETS early limit
  15. GRB 060218: Refined analysis of the radio afterglow
  16. GRB 060223A:Xinglong optical limits
  17. GRB 060223B: ART optical limits
  18. GRB 060223B: Swift-BAT refined analysis
  19. GRB 060223a: Swift/UVOT refined analysis
  20. GRB 060223: Swift XRT Team preliminary analysis
  21. GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux
  22. GRB 060223B: Swift detection of a bright burst
  23. GRB 060223: Swift-BAT refined analysis
  24. GRB 060218: rebrightening
  25. Correction to GCN 4816 on GRB060218
  26. GRB 060218/SN 2006aj: optical observations
  27. GRB060218: Optical brightening in V and R
  28. GRB 060223: Keck redshift
  29. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  30. GRB 060223: Swift detection of a burst
  31. Spectral properties of GRB060218/SN2006aj
  32. GRB 060219: Swift-BAT refined analysis
  33. GRB 060218: rebrightening
  34. GRB 060218: emergence of the underlying SN spectrum
  35. GRB 060218: Decline in r-band flux
  36. GRB 060218: spectroscopic observations
  37. GRB 060218: Further refined analysis of the Swift-BAT burst
  38. GRB 060218: Likely an underluminous GRB
  39. GRB060218: Optical Spectroscopy of GRB-SN
  40. GRB060218: VLT spectroscopy
  41. GRB 060218: Optical Observations at Xinglong Obs.
  42. GRB 060219: SDSS galaxy inside XRT error circle
  43. GRB060218: UV Detection and Light Curves
  44. GRB060219: SARA Observations
  45. GRB 060219: Swift/UVOT Upper Limits
  46. GRB 060219: Swift-XRT Team refined analysis
  47. GRB 051221B: Swift-XRT Team Refined Analysis
  48. GRB 060219: Partial refined analysis of the Swift-BAT burst
  49. GRB060218: Radio Afterglow Discovery
  50. GRB 060219: Swift-XRT position typo correction
  51. GRB 060218: MDM Redshift
  52. GRB 060219: Swift-XRT position
  53. GRB 060218: optical/nIR observations at La Palma
  54. GRB060219: SDSS pre-burst observations
  55. GRB 060219: Swift-BAT detection of a weak burst
  56. Oddball GRB 060218, transient or GRB?
  57. GRB060218: Swift/XRT Team preliminary analysis of the possible burst
  58. Brightening of the Optical Counterpart of the Possible GRB 060218
  59. GRB 060218: MDM Observations
  60. GRB 060218: Pre-burst detection of a possible host galaxy
  61. GRB 060218A: ROTSE-III Possible Optical Flare
  62. GRB060218: Swift/XRT refined position of a possible burst
  63. Preliminary refined analysis of the Swift-BAT trigger 191157
  64. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  65. GRB 060211B: Swift/UVOT Upper Limits
  66. GRB060218 : SDSS pre-burst observations
  67. GRB 060218: Swift XRT Position
  68. GRB 060218: Swift-BAT detection of a possible burst
  69. GRB 060213: optical afterglow not confirmed
  70. Swift UVOT observations of GRB060213
  71. GRB 060211B: Skynet Observations
  72. GRB 060213: optical afterglow candidate
  73. GRB060213: Swift XRT observations and possible afterglow candidate
  74. GRB 060213: pseudo-z = 3.5 +/- 0.35 from spectral parameters
  75. GRB 060206: Confirmation of Rapid Fading at Optical Wavelengths
  76. GRB060213: MASTER final result
  77. GRB 060211b: WIRO NIR Observations
  78. GRB060213:_MASTER_optical_observation
  79. GRB060206: Swift XRT observations of an unbroken powerlaw decay
  80. Konus-Wind observation of bright hard GRB 060213
  81. GRB 060213: IPN localization
  82. GRB 060210: Radio Observations
  83. GRB 060211a: WIRO NIR Observations
  84. GRB060211B: REM optical and NIR observations
  85. GRB 060211B: BAT detects no additional burst emission beyond T + 122 sec
  86. GRB 060211A: Further refined analysis of the Swift burst
  87. GRB060121: optical observations
  88. GRB060110: optical observations
  89. GRB060105: optical observations
  90. GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
  91. GRB 060211b: P60 Observations
  92. GRB 060211A: Partial refined analysis on the Swift-BAT burst
  93. GRB 060206: SOAR Detections
  94. GRB 050826: Optical Afterglow and Host Galaxy
  95. GRB 060210: Further refined analysis of the Swift-BAT burst
  96. GRB 060211B: Swift/BAT refined analysis
  97. GRB060210: Swift/UVOT Upper Limits
  98. GRB 060211B: Swift-XRT Team refined analysis
  99. GRB060211b: optical observation
  100. GRB060211B: Swift/XRT position

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