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

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