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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. GRB060602 - SDSS Pre-Burst Observations
  2. GRB 060602: Swift detection of a burst
  3. GRB 060502A: Optical afterglow observations
  4. GRB 060526: Break in X-ray light curve
  5. GRB 060526: RTT150 optical observations
  6. GRB060526, optical observations
  7. GRB 051227 : WIDGET simultaneous optical observations
  8. GRB 051028 : WIDGET pre-trigger limit
  9. GRB 060526: RTT150 optical observations
  10. GRB 060526: Multiple Optical Flares
  11. GRB060526: afterglow fitting and probable jet break
  12. GRB 060526: RTT150 optical observations
  13. GRB060526: Optical counterpart from MIRO
  14. GRB060502b: optical observations
  15. GRB 060526: RTT150 optical observations
  16. GRB 060526: Tautenburg OT observation and light curve fitting
  17. GRB060526: optical observations
  18. GRB 060526: SMARTS optical/IR afterglow observations
  19. GRB060526: possible break in the optical light curve
  20. GRB 060526: REM observations
  21. GRB 060526: RTT150 optical observations, afterglow flattening
  22. GRB 060526: Optical Flare
  23. GRB 060526: MDM-2.4m Observations
  24. GRB 060526: Refined analysis of the Swift-BAT burst
  25. GRB 060526: RTT150 optical observations
  26. GRB060526: Further Swift-UVOT Observations
  27. GRB060526, optical observations
  28. GRB 060526: Magellan Redshift
  29. GRB 060526 Lulin optical observation
  30. GRB 060526: Swift/XRT Team refined analysis
  31. GRB 060526: TNG optical observations
  32. GRB 060526: ROTSE-III Observations of Optical Counterpart
  33. GRB 060526: Watcher Observations
  34. GRB060526 - SDSS Pre-burst Observations
  35. GRB 060526: Continued emission for the Swift burst
  36. GRB 060526: Swift detection of a burst with x-ray and optical afterglow
  37. GRB060505: VLT observations of the optical afterglow
  38. GRB 060413 : WIDGET simultaneous optical observations
  39. GRB 060522: Swift/UVOT Observations: Correction
  40. GRB 060522: Swift/UVOT Observations of the Optical Afterglow
  41. XMM-Newton observation of GRB060510b
  42. GRB060512: Late-Time P200 Observations
  43. GRB060522: z = 5.11 Keck-LRIS Redshift
  44. GRB 060522: Swift/XRT Team refined analysis
  45. GRB 060522: Swift-BAT Refined Analysis
  46. GRB 060522: REM NIR observations
  47. GRB 060522: TNG optical observations
  48. GRB 060522: Swift detection of a burst with possible optical afterglow
  49. GRB 060512: reanalysis of optical spectra
  50. GRB 060515: NIR observation
  51. GRB 060210: Jet Break in the XRT light curve
  52. GRB 060516: Refined analysis of the Swift-BAT burst
  53. GRB 060512: TNG optical spectroscopy
  54. GRB 060516: Swift detection of a burst
  55. GRB060515: P200 NIR Observations
  56. GRB 060505 BAT refined analysis
  57. GRB 060515 BAT refined analysis
  58. GRB 060512: TAROT optical observation
  59. GRB 060515: Swift/XRT Team refined analysis
  60. GRB 060515: Swift/UVOT Upper Limits
  61. GRB 060515: Swift/XRT position
  62. GRB 060515: Super-LOTIS Observations
  63. GRB060515: Swift/UVOT initial observation
  64. GRB 060515: TAROT optical observation
  65. GRB 060515: ROTSE-III Optical Limits
  66. GRB 060515: Swift detection of a burst
  67. VLT optical spectroscopy of GRB 060512
  68. Swift/UVOT observations of GRB060512.
  69. GRB 060512: Subaru NIR observation
  70. GRB060512: Swift XRT Team refined analysis
  71. GRB 060512: 1.54m Kuiper Observations
  72. GRB 060512: Detection of NIR afterglow
  73. GRB 060512: P60 Observations
  74. GRB 060512: Swift-BAT Refined Analysis
  75. GRB 060505 - OT candidate + galaxy spectrum
  76. GRB 060512: optical decay
  77. GRB 060512: REM NIR observations
  78. GRB060512 - SDSS Pre-Burst Observations
  79. GRB060512 Name Correction: LT Afterglow detection
  80. GRB060512: Liverpool Telescope Afterglow detection
  81. GRB 060512: Swift detection of a burst with an optical afterglow
  82. GRB 060510A: Swift/UVOT Detection of an Optical Afterglow
  83. GRB 060505: X-ray afterglow - Correction -
  84. GRB 060505: X-ray afterglow
  85. Konus-Wind observation of GRB 060510A
  86. GRB060418: optical observations
  87. GRB 060428a, SMARTS optical/IR afterglow detection
  88. GRB060510B: Swift XRT refined analysis
  89. GRB 060510B: Swift/UVOT Upper Limits
  90. GRB 060510A: Refined analysis of the Swift-BAT burst
  91. GRB 060510B: Swift-BAT Refined Analysis
  92. GRB060510A: XRT refined analysis
  93. GRB060510 - SDSS Pre-Burst Observations
  94. GRB 060510b: Redshift
  95. GRB060510B : Faulkes North Telescope detection
  96. GRB 060510B : Planned XMM-Newton observation
  97. GRB 060510b: Gemini NIR observations
  98. GRB 060510B: Super-LOTIS Observations
  99. GRB 060510b: NIR observations
  100. GRB 060510B: Coordinate correction

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