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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 060605: RTT150 optical observations
  2. GRB 060607: REM NIR afterglow
  3. GRB 060607: Swift detection of a burst with bright optical counterpart
  4. GRB 060522: PROMPT Optical Limits
  5. GRB 060605 BAT refined analysis
  6. GRB 060605: Xinglong TNT optical observations
  7. GRB060602B : REM infrared observations
  8. GRB060605: Swift/UVOT detections
  9. GRB 060605: Swift-XRT Team refined analysis
  10. SALT spectroscopy of GRB 060605
  11. GRB 060605: TNG optical observations
  12. GRB 060605: RTT150 optical observations
  13. GRB060605: Spectral Observations and Redshift
  14. GRB 060605: ROTSE-III Optical Counterpart
  15. GRB 060605: Swift detection of a burst with optical counterpart
  16. GRB 060605: ROTSE-III Detection of Optical Counterpart
  17. GRB060604: Swift/UVOT detections
  18. GRB 060604: redshift
  19. GRB 060512: Keck Redshift
  20. GRB 060604 optical photometry
  21. GRB 060604: Swift-XRT Team refined analysis
  22. GRB 060604: BAT refined analysis
  23. GRB 060604A: ROTSE-III Optical Limits
  24. GRB 060604: Swift detection of a burst with possible optical counterpart
  25. GRB 060602A: Swift-BAT Refined Analysis: Correction
  26. GRB 060602B: XMM-Newton Survey Source
  27. GRB 060602B: Swift-XRT Refined Analysis
  28. GRB 060602B: Swift-BAT Refined Analysis
  29. GRB 060602B: Swift/UVOT observations
  30. GRB 060602A: Swift-BAT Refined Analysis
  31. GRB 060602B: RTT150 optical observations
  32. GRB 060211A : WIDGET simultaneous optical observations
  33. GRB060602A: optical observations(/transient?)
  34. GRB 060526: Tautenburg Second Epoch Observations
  35. GRB060602A: Bootes-IR observations
  36. GRB 060602B: Swift detection of a burst
  37. GRB060602B: Watcher observations - no OT candidate
  38. GRB060602B: BOOTES-IR candidate afterglow
  39. GRB060602 - SDSS Pre-Burst Observations
  40. GRB 060602: Swift detection of a burst
  41. GRB 060502A: Optical afterglow observations
  42. GRB 060526: Break in X-ray light curve
  43. GRB 060526: RTT150 optical observations
  44. GRB060526, optical observations
  45. GRB 051227 : WIDGET simultaneous optical observations
  46. GRB 051028 : WIDGET pre-trigger limit
  47. GRB 060526: RTT150 optical observations
  48. GRB 060526: Multiple Optical Flares
  49. GRB060526: afterglow fitting and probable jet break
  50. GRB 060526: RTT150 optical observations
  51. GRB060526: Optical counterpart from MIRO
  52. GRB060502b: optical observations
  53. GRB 060526: RTT150 optical observations
  54. GRB 060526: Tautenburg OT observation and light curve fitting
  55. GRB060526: optical observations
  56. GRB 060526: SMARTS optical/IR afterglow observations
  57. GRB060526: possible break in the optical light curve
  58. GRB 060526: REM observations
  59. GRB 060526: RTT150 optical observations, afterglow flattening
  60. GRB 060526: Optical Flare
  61. GRB 060526: MDM-2.4m Observations
  62. GRB 060526: Refined analysis of the Swift-BAT burst
  63. GRB 060526: RTT150 optical observations
  64. GRB060526: Further Swift-UVOT Observations
  65. GRB060526, optical observations
  66. GRB 060526: Magellan Redshift
  67. GRB 060526 Lulin optical observation
  68. GRB 060526: Swift/XRT Team refined analysis
  69. GRB 060526: TNG optical observations
  70. GRB 060526: ROTSE-III Observations of Optical Counterpart
  71. GRB 060526: Watcher Observations
  72. GRB060526 - SDSS Pre-burst Observations
  73. GRB 060526: Continued emission for the Swift burst
  74. GRB 060526: Swift detection of a burst with x-ray and optical afterglow
  75. GRB060505: VLT observations of the optical afterglow
  76. GRB 060413 : WIDGET simultaneous optical observations
  77. GRB 060522: Swift/UVOT Observations: Correction
  78. GRB 060522: Swift/UVOT Observations of the Optical Afterglow
  79. XMM-Newton observation of GRB060510b
  80. GRB060512: Late-Time P200 Observations
  81. GRB060522: z = 5.11 Keck-LRIS Redshift
  82. GRB 060522: Swift/XRT Team refined analysis
  83. GRB 060522: Swift-BAT Refined Analysis
  84. GRB 060522: REM NIR observations
  85. GRB 060522: TNG optical observations
  86. GRB 060522: Swift detection of a burst with possible optical afterglow
  87. GRB 060512: reanalysis of optical spectra
  88. GRB 060515: NIR observation
  89. GRB 060210: Jet Break in the XRT light curve
  90. GRB 060516: Refined analysis of the Swift-BAT burst
  91. GRB 060512: TNG optical spectroscopy
  92. GRB 060516: Swift detection of a burst
  93. GRB060515: P200 NIR Observations
  94. GRB 060505 BAT refined analysis
  95. GRB 060515 BAT refined analysis
  96. GRB 060512: TAROT optical observation
  97. GRB 060515: Swift/XRT Team refined analysis
  98. GRB 060515: Swift/UVOT Upper Limits
  99. GRB 060515: Swift/XRT position
  100. GRB 060515: Super-LOTIS Observations

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