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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 060602B: XMM-Newton Survey Source
  2. GRB 060602B: Swift-XRT Refined Analysis
  3. GRB 060602B: Swift-BAT Refined Analysis
  4. GRB 060602B: Swift/UVOT observations
  5. GRB 060602A: Swift-BAT Refined Analysis
  6. GRB 060602B: RTT150 optical observations
  7. GRB 060211A : WIDGET simultaneous optical observations
  8. GRB060602A: optical observations(/transient?)
  9. GRB 060526: Tautenburg Second Epoch Observations
  10. GRB060602A: Bootes-IR observations
  11. GRB 060602B: Swift detection of a burst
  12. GRB060602B: Watcher observations - no OT candidate
  13. GRB060602B: BOOTES-IR candidate afterglow
  14. GRB060602 - SDSS Pre-Burst Observations
  15. GRB 060602: Swift detection of a burst
  16. GRB 060502A: Optical afterglow observations
  17. GRB 060526: Break in X-ray light curve
  18. GRB 060526: RTT150 optical observations
  19. GRB060526, optical observations
  20. GRB 051227 : WIDGET simultaneous optical observations
  21. GRB 051028 : WIDGET pre-trigger limit
  22. GRB 060526: RTT150 optical observations
  23. GRB 060526: Multiple Optical Flares
  24. GRB060526: afterglow fitting and probable jet break
  25. GRB 060526: RTT150 optical observations
  26. GRB060526: Optical counterpart from MIRO
  27. GRB060502b: optical observations
  28. GRB 060526: RTT150 optical observations
  29. GRB 060526: Tautenburg OT observation and light curve fitting
  30. GRB060526: optical observations
  31. GRB 060526: SMARTS optical/IR afterglow observations
  32. GRB060526: possible break in the optical light curve
  33. GRB 060526: REM observations
  34. GRB 060526: RTT150 optical observations, afterglow flattening
  35. GRB 060526: Optical Flare
  36. GRB 060526: MDM-2.4m Observations
  37. GRB 060526: Refined analysis of the Swift-BAT burst
  38. GRB 060526: RTT150 optical observations
  39. GRB060526: Further Swift-UVOT Observations
  40. GRB060526, optical observations
  41. GRB 060526: Magellan Redshift
  42. GRB 060526 Lulin optical observation
  43. GRB 060526: Swift/XRT Team refined analysis
  44. GRB 060526: TNG optical observations
  45. GRB 060526: ROTSE-III Observations of Optical Counterpart
  46. GRB 060526: Watcher Observations
  47. GRB060526 - SDSS Pre-burst Observations
  48. GRB 060526: Continued emission for the Swift burst
  49. GRB 060526: Swift detection of a burst with x-ray and optical afterglow
  50. GRB060505: VLT observations of the optical afterglow
  51. GRB 060413 : WIDGET simultaneous optical observations
  52. GRB 060522: Swift/UVOT Observations: Correction
  53. GRB 060522: Swift/UVOT Observations of the Optical Afterglow
  54. XMM-Newton observation of GRB060510b
  55. GRB060512: Late-Time P200 Observations
  56. GRB060522: z = 5.11 Keck-LRIS Redshift
  57. GRB 060522: Swift/XRT Team refined analysis
  58. GRB 060522: Swift-BAT Refined Analysis
  59. GRB 060522: REM NIR observations
  60. GRB 060522: TNG optical observations
  61. GRB 060522: Swift detection of a burst with possible optical afterglow
  62. GRB 060512: reanalysis of optical spectra
  63. GRB 060515: NIR observation
  64. GRB 060210: Jet Break in the XRT light curve
  65. GRB 060516: Refined analysis of the Swift-BAT burst
  66. GRB 060512: TNG optical spectroscopy
  67. GRB 060516: Swift detection of a burst
  68. GRB060515: P200 NIR Observations
  69. GRB 060505 BAT refined analysis
  70. GRB 060515 BAT refined analysis
  71. GRB 060512: TAROT optical observation
  72. GRB 060515: Swift/XRT Team refined analysis
  73. GRB 060515: Swift/UVOT Upper Limits
  74. GRB 060515: Swift/XRT position
  75. GRB 060515: Super-LOTIS Observations
  76. GRB060515: Swift/UVOT initial observation
  77. GRB 060515: TAROT optical observation
  78. GRB 060515: ROTSE-III Optical Limits
  79. GRB 060515: Swift detection of a burst
  80. VLT optical spectroscopy of GRB 060512
  81. Swift/UVOT observations of GRB060512.
  82. GRB 060512: Subaru NIR observation
  83. GRB060512: Swift XRT Team refined analysis
  84. GRB 060512: 1.54m Kuiper Observations
  85. GRB 060512: Detection of NIR afterglow
  86. GRB 060512: P60 Observations
  87. GRB 060512: Swift-BAT Refined Analysis
  88. GRB 060505 - OT candidate + galaxy spectrum
  89. GRB 060512: optical decay
  90. GRB 060512: REM NIR observations
  91. GRB060512 - SDSS Pre-Burst Observations
  92. GRB060512 Name Correction: LT Afterglow detection
  93. GRB060512: Liverpool Telescope Afterglow detection
  94. GRB 060512: Swift detection of a burst with an optical afterglow
  95. GRB 060510A: Swift/UVOT Detection of an Optical Afterglow
  96. GRB 060505: X-ray afterglow - Correction -
  97. GRB 060505: X-ray afterglow
  98. Konus-Wind observation of GRB 060510A
  99. GRB060418: optical observations
  100. GRB 060428a, SMARTS optical/IR afterglow detection

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