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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 060505: X-ray afterglow - Correction -
  2. GRB 060505: X-ray afterglow
  3. Konus-Wind observation of GRB 060510A
  4. GRB060418: optical observations
  5. GRB 060428a, SMARTS optical/IR afterglow detection
  6. GRB060510B: Swift XRT refined analysis
  7. GRB 060510B: Swift/UVOT Upper Limits
  8. GRB 060510A: Refined analysis of the Swift-BAT burst
  9. GRB 060510B: Swift-BAT Refined Analysis
  10. GRB060510A: XRT refined analysis
  11. GRB060510 - SDSS Pre-Burst Observations
  12. GRB 060510b: Redshift
  13. GRB060510B : Faulkes North Telescope detection
  14. GRB 060510B : Planned XMM-Newton observation
  15. GRB 060510b: Gemini NIR observations
  16. GRB 060510B: Super-LOTIS Observations
  17. GRB 060510b: NIR observations
  18. GRB 060510B: Coordinate correction
  19. GRB 060510B: MDM Observations and candidate OT
  20. GRB 060510B: Swift detection of a burst
  21. GRB 060510: Swift detection of a burst with optical transient
  22. GRB060507: optical afterglow detection
  23. GRB060502B: improvement in the XRT afterglow position
  24. GRB 060507: BART limit
  25. GRB 060507: Final Refined analysis of the Swift-BAT burst
  26. GRB 060507: Swift-BAT Refined Analysis
  27. GRB 060505: PROMPT Observations
  28. GRB 060507: Swift/UVOT Upper Limits
  29. GRB 060507: Swift XRT Team Refined Analysis
  30. GRB 060507: MDM Optical Upper Limit
  31. GRB060507: Swift XRT position
  32. GRB 060507: Swift detection of a burst
  33. GRB 060429: Suzaku WAM observation
  34. GRB060505: Swift/UVOT Observations
  35. GRB 060505: Swift XRT Team Refined Analysis
  36. GRB060425: new MASTER survey method
  37. GRB 060306: Further Analysis of SOAR and APO NIR Observations
  38. GRB 060505: Swift XRT afterglow canditate position
  39. GRB 060502b: Second epoch Gemini observations
  40. GRB 060505: Swift-BAT detection of a weak burst
  41. GRB 060428B: spectroscopy
  42. GRB 060502B: optical observations
  43. GRB 060502B: AROMA refined photometric calibration
  44. GRB 060502B MDM Follow-up Observation
  45. GRB 060502b: Gemini imaging and spectroscopy
  46. GRB060502A, optical observation
  47. GRB 060502B: Swift/UVOT upper limits
  48. GRB 060502A: Swift/UVOT source detection
  49. GRB 060429: Refined IPN error box and Konus-Wind spectrum
  50. GRB 060502B: MDM Optical Observation
  51. GRB 060502B: AROMA optical observations
  52. GRB 060502B: Refined analysis of the Swift-BAT short burst
  53. GRB060502B: Swift XRT Team refined analysis
  54. Short GRB 060502B: Tautenburg Observation
  55. GRB 060427B Milagro GeV/TeV Observations
  56. GRB 060502A: TTT Observations
  57. GRB060502B: correction to XRT position
  58. GRB 060501: P60 Observations and Candidate Retraction
  59. GRB 060502B: Xinglong optical observation
  60. GRB 060502B: MASTER optical observations
  61. GRB 060502B: Swift detection of a short burst
  62. GRB060502: Swift-XRT refined analysis
  63. GRB 060502: Swift-BAT refined analysis
  64. GRB060502: Gemini spectroscopy
  65. GRB 060502: APO Spectroscopic Observations
  66. GRB060501: Swift UVOT followup observations
  67. GRB060502: Super-LOTIS Observations
  68. GRB 060502: P60 Afterglow Confirmation
  69. GRB 060502: Swift detection of a burst with an optical counterpart
  70. GRB 060501: MDM Observations
  71. GRB060501: Super-LOTIS observations
  72. GRB060501: P60 imaging and afterglow candidate
  73. GRB 060501: Refined analysis of the Swift-BAT burst
  74. GRB060501: Swift XRT position
  75. GRB 060501: ROTSE-III Optical Limits
  76. GRB 060501: Swift detection of a burst
  77. IPN triangulation of GRB060429 (short/hard)
  78. Konus-Wind observation of GRB 060427B
  79. GRB060428B - SDSS Pre-Burst Observations
  80. GRB060428B: optical observation
  81. GRB060428B: possible detection of an optical counterpart by Swift/UVOT.
  82. GRB 060428B: MDM Observations
  83. GRB 060428A: PROMPT Observations
  84. GRB 060427B: MASTER optical observations
  85. GRB060428B: Swift XRT Team refined analysis
  86. GRB 060427B: IPN localization of a short hard burst
  87. GRB 060428B: Refined analysis of the Swift-BAT burst
  88. GRB 060428B: Xinglong I-band limit
  89. GRB 060428B: KAIT observations
  90. GRB060425:MASTER optical limit
  91. GRB 051117A: Bright host galaxy not confirmed
  92. GRB060428A: Swift/UVOT observations.
  93. GRB060428B, optical observation
  94. GRB 060428A: Refined analysis of the Swift-BAT burst
  95. GRB 060428b : Kiso R-band limit
  96. GRB060427:MASTER optical limit
  97. GRB 060428b: Optical afterglow candidate
  98. GRB060428A: Swift XRT Team refined analysis
  99. GRB 060428B: Swift detection of a burst
  100. GRB 060427: NIR observations

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