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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 060526: RTT150 optical observations
  2. GRB060526, optical observations
  3. GRB 051227 : WIDGET simultaneous optical observations
  4. GRB 051028 : WIDGET pre-trigger limit
  5. GRB 060526: RTT150 optical observations
  6. GRB 060526: Multiple Optical Flares
  7. GRB060526: afterglow fitting and probable jet break
  8. GRB 060526: RTT150 optical observations
  9. GRB060526: Optical counterpart from MIRO
  10. GRB060502b: optical observations
  11. GRB 060526: RTT150 optical observations
  12. GRB 060526: Tautenburg OT observation and light curve fitting
  13. GRB060526: optical observations
  14. GRB 060526: SMARTS optical/IR afterglow observations
  15. GRB060526: possible break in the optical light curve
  16. GRB 060526: REM observations
  17. GRB 060526: RTT150 optical observations, afterglow flattening
  18. GRB 060526: Optical Flare
  19. GRB 060526: MDM-2.4m Observations
  20. GRB 060526: Refined analysis of the Swift-BAT burst
  21. GRB 060526: RTT150 optical observations
  22. GRB060526: Further Swift-UVOT Observations
  23. GRB060526, optical observations
  24. GRB 060526: Magellan Redshift
  25. GRB 060526 Lulin optical observation
  26. GRB 060526: Swift/XRT Team refined analysis
  27. GRB 060526: TNG optical observations
  28. GRB 060526: ROTSE-III Observations of Optical Counterpart
  29. GRB 060526: Watcher Observations
  30. GRB060526 - SDSS Pre-burst Observations
  31. GRB 060526: Continued emission for the Swift burst
  32. GRB 060526: Swift detection of a burst with x-ray and optical afterglow
  33. GRB060505: VLT observations of the optical afterglow
  34. GRB 060413 : WIDGET simultaneous optical observations
  35. GRB 060522: Swift/UVOT Observations: Correction
  36. GRB 060522: Swift/UVOT Observations of the Optical Afterglow
  37. XMM-Newton observation of GRB060510b
  38. GRB060512: Late-Time P200 Observations
  39. GRB060522: z = 5.11 Keck-LRIS Redshift
  40. GRB 060522: Swift/XRT Team refined analysis
  41. GRB 060522: Swift-BAT Refined Analysis
  42. GRB 060522: REM NIR observations
  43. GRB 060522: TNG optical observations
  44. GRB 060522: Swift detection of a burst with possible optical afterglow
  45. GRB 060512: reanalysis of optical spectra
  46. GRB 060515: NIR observation
  47. GRB 060210: Jet Break in the XRT light curve
  48. GRB 060516: Refined analysis of the Swift-BAT burst
  49. GRB 060512: TNG optical spectroscopy
  50. GRB 060516: Swift detection of a burst
  51. GRB060515: P200 NIR Observations
  52. GRB 060505 BAT refined analysis
  53. GRB 060515 BAT refined analysis
  54. GRB 060512: TAROT optical observation
  55. GRB 060515: Swift/XRT Team refined analysis
  56. GRB 060515: Swift/UVOT Upper Limits
  57. GRB 060515: Swift/XRT position
  58. GRB 060515: Super-LOTIS Observations
  59. GRB060515: Swift/UVOT initial observation
  60. GRB 060515: TAROT optical observation
  61. GRB 060515: ROTSE-III Optical Limits
  62. GRB 060515: Swift detection of a burst
  63. VLT optical spectroscopy of GRB 060512
  64. Swift/UVOT observations of GRB060512.
  65. GRB 060512: Subaru NIR observation
  66. GRB060512: Swift XRT Team refined analysis
  67. GRB 060512: 1.54m Kuiper Observations
  68. GRB 060512: Detection of NIR afterglow
  69. GRB 060512: P60 Observations
  70. GRB 060512: Swift-BAT Refined Analysis
  71. GRB 060505 - OT candidate + galaxy spectrum
  72. GRB 060512: optical decay
  73. GRB 060512: REM NIR observations
  74. GRB060512 - SDSS Pre-Burst Observations
  75. GRB060512 Name Correction: LT Afterglow detection
  76. GRB060512: Liverpool Telescope Afterglow detection
  77. GRB 060512: Swift detection of a burst with an optical afterglow
  78. GRB 060510A: Swift/UVOT Detection of an Optical Afterglow
  79. GRB 060505: X-ray afterglow - Correction -
  80. GRB 060505: X-ray afterglow
  81. Konus-Wind observation of GRB 060510A
  82. GRB060418: optical observations
  83. GRB 060428a, SMARTS optical/IR afterglow detection
  84. GRB060510B: Swift XRT refined analysis
  85. GRB 060510B: Swift/UVOT Upper Limits
  86. GRB 060510A: Refined analysis of the Swift-BAT burst
  87. GRB 060510B: Swift-BAT Refined Analysis
  88. GRB060510A: XRT refined analysis
  89. GRB060510 - SDSS Pre-Burst Observations
  90. GRB 060510b: Redshift
  91. GRB060510B : Faulkes North Telescope detection
  92. GRB 060510B : Planned XMM-Newton observation
  93. GRB 060510b: Gemini NIR observations
  94. GRB 060510B: Super-LOTIS Observations
  95. GRB 060510b: NIR observations
  96. GRB 060510B: Coordinate correction
  97. GRB 060510B: MDM Observations and candidate OT
  98. GRB 060510B: Swift detection of a burst
  99. GRB 060510: Swift detection of a burst with optical transient
  100. GRB060507: optical afterglow detection

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