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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. GRB060602A: Bootes-IR observations
  2. GRB 060602B: Swift detection of a burst
  3. GRB060602B: Watcher observations - no OT candidate
  4. GRB060602B: BOOTES-IR candidate afterglow
  5. GRB060602 - SDSS Pre-Burst Observations
  6. GRB 060602: Swift detection of a burst
  7. GRB 060502A: Optical afterglow observations
  8. GRB 060526: Break in X-ray light curve
  9. GRB 060526: RTT150 optical observations
  10. GRB060526, optical observations
  11. GRB 051227 : WIDGET simultaneous optical observations
  12. GRB 051028 : WIDGET pre-trigger limit
  13. GRB 060526: RTT150 optical observations
  14. GRB 060526: Multiple Optical Flares
  15. GRB060526: afterglow fitting and probable jet break
  16. GRB 060526: RTT150 optical observations
  17. GRB060526: Optical counterpart from MIRO
  18. GRB060502b: optical observations
  19. GRB 060526: RTT150 optical observations
  20. GRB 060526: Tautenburg OT observation and light curve fitting
  21. GRB060526: optical observations
  22. GRB 060526: SMARTS optical/IR afterglow observations
  23. GRB060526: possible break in the optical light curve
  24. GRB 060526: REM observations
  25. GRB 060526: RTT150 optical observations, afterglow flattening
  26. GRB 060526: Optical Flare
  27. GRB 060526: MDM-2.4m Observations
  28. GRB 060526: Refined analysis of the Swift-BAT burst
  29. GRB 060526: RTT150 optical observations
  30. GRB060526: Further Swift-UVOT Observations
  31. GRB060526, optical observations
  32. GRB 060526: Magellan Redshift
  33. GRB 060526 Lulin optical observation
  34. GRB 060526: Swift/XRT Team refined analysis
  35. GRB 060526: TNG optical observations
  36. GRB 060526: ROTSE-III Observations of Optical Counterpart
  37. GRB 060526: Watcher Observations
  38. GRB060526 - SDSS Pre-burst Observations
  39. GRB 060526: Continued emission for the Swift burst
  40. GRB 060526: Swift detection of a burst with x-ray and optical afterglow
  41. GRB060505: VLT observations of the optical afterglow
  42. GRB 060413 : WIDGET simultaneous optical observations
  43. GRB 060522: Swift/UVOT Observations: Correction
  44. GRB 060522: Swift/UVOT Observations of the Optical Afterglow
  45. XMM-Newton observation of GRB060510b
  46. GRB060512: Late-Time P200 Observations
  47. GRB060522: z = 5.11 Keck-LRIS Redshift
  48. GRB 060522: Swift/XRT Team refined analysis
  49. GRB 060522: Swift-BAT Refined Analysis
  50. GRB 060522: REM NIR observations
  51. GRB 060522: TNG optical observations
  52. GRB 060522: Swift detection of a burst with possible optical afterglow
  53. GRB 060512: reanalysis of optical spectra
  54. GRB 060515: NIR observation
  55. GRB 060210: Jet Break in the XRT light curve
  56. GRB 060516: Refined analysis of the Swift-BAT burst
  57. GRB 060512: TNG optical spectroscopy
  58. GRB 060516: Swift detection of a burst
  59. GRB060515: P200 NIR Observations
  60. GRB 060505 BAT refined analysis
  61. GRB 060515 BAT refined analysis
  62. GRB 060512: TAROT optical observation
  63. GRB 060515: Swift/XRT Team refined analysis
  64. GRB 060515: Swift/UVOT Upper Limits
  65. GRB 060515: Swift/XRT position
  66. GRB 060515: Super-LOTIS Observations
  67. GRB060515: Swift/UVOT initial observation
  68. GRB 060515: TAROT optical observation
  69. GRB 060515: ROTSE-III Optical Limits
  70. GRB 060515: Swift detection of a burst
  71. VLT optical spectroscopy of GRB 060512
  72. Swift/UVOT observations of GRB060512.
  73. GRB 060512: Subaru NIR observation
  74. GRB060512: Swift XRT Team refined analysis
  75. GRB 060512: 1.54m Kuiper Observations
  76. GRB 060512: Detection of NIR afterglow
  77. GRB 060512: P60 Observations
  78. GRB 060512: Swift-BAT Refined Analysis
  79. GRB 060505 - OT candidate + galaxy spectrum
  80. GRB 060512: optical decay
  81. GRB 060512: REM NIR observations
  82. GRB060512 - SDSS Pre-Burst Observations
  83. GRB060512 Name Correction: LT Afterglow detection
  84. GRB060512: Liverpool Telescope Afterglow detection
  85. GRB 060512: Swift detection of a burst with an optical afterglow
  86. GRB 060510A: Swift/UVOT Detection of an Optical Afterglow
  87. GRB 060505: X-ray afterglow - Correction -
  88. GRB 060505: X-ray afterglow
  89. Konus-Wind observation of GRB 060510A
  90. GRB060418: optical observations
  91. GRB 060428a, SMARTS optical/IR afterglow detection
  92. GRB060510B: Swift XRT refined analysis
  93. GRB 060510B: Swift/UVOT Upper Limits
  94. GRB 060510A: Refined analysis of the Swift-BAT burst
  95. GRB 060510B: Swift-BAT Refined Analysis
  96. GRB060510A: XRT refined analysis
  97. GRB060510 - SDSS Pre-Burst Observations
  98. GRB 060510b: Redshift
  99. GRB060510B : Faulkes North Telescope detection
  100. GRB 060510B : Planned XMM-Newton observation

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