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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 061004: Las Campanas Optical/NIR Observations
  2. GRB061004: Swift/UVOT optical observations
  3. GRB 061004: Swift-XRT Team Refined Analysis
  4. GRB 061004, Swift BAT refined analysis
  5. GRB 061004: Nearby 2MASS Galaxy
  6. GRB 060928: Correction to GCN 5690
  7. GRB 061004: Swift detection of a burst
  8. GRB 060928: 2 pseudo-z from 2 detections spectral parameters
  9. Konus-Wind observation of GRB 060928
  10. GRB 060928: Suzaku/WAM observation of the prompt emission
  11. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  12. GRB 060928: Swift observations
  13. GRB 060928: RHESSI Spectral Fit
  14. IPN triangulation of GRB060928 (long, exceptionally bright)
  15. GRB061002: Swift UVOT followup observations
  16. GRB 060930: near-IR afterglow candidate
  17. GRB 061002: Swift-XRT Team Refined Analysis
  18. VLA observations of GRB 060926
  19. GRB061002 - SDSS Pre-Burst Observations
  20. GRB 061002, Swift-BAT refined analysis
  21. GRB061002: MASTER-VWF-Kislovodsk observations
  22. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  23. GRB 061002: Swift detection of a burst
  24. GRB 060908: Detection of a possible host
  25. GRB 060923A: Probable host galaxy in the R-band
  26. GRB 060807: Detection of a possible host galaxy
  27. GRB 060923A: VLA K-band Observations
  28. GRB060930: Faulkes Telescope South observation
  29. GRB 060930: Xinglong TNT optical observations
  30. GRB 060929: Further XRT Refined Analysis
  31. GRB 060929: Swift/UVOT Optical Observations
  32. GRB 060930: ROTSE-III Optical Limits
  33. GRB 060930: A long X-ray rich GRB detected by INTEGRAL
  34. GRB 060927 : GAO 150cm telescope optical observation
  35. GRB060929: Swift-XRT refined analysis.
  36. GRB 060929, Swift-BAT further refined analysis - late-time flare
  37. GRB 060929: TNG K-band observations
  38. GRB 060929, Swift-BAT refined analysis
  39. GRB060929: Optical limit
  40. GRB 060929: BART observation
  41. GRB 060929: MASTER-VWF-Kislovodsk observations
  42. GRB 060929: BOOTES-IR & OSN observations
  43. Liverpool Telescope observations of GRB 060929
  44. GRB 060929: Swift detection of a burst
  45. GRB060908: optical observations
  46. GRB 060729: An update on the late-time Swift observations
  47. GRB 060927: Spectroscopic redshift z=5.6
  48. IBAS Alert n.3501: not a GRB
  49. IBAS Alert n.3500: not a GRB
  50. GRB060923C: optical limit
  51. GRB060927: optical observations
  52. test of new software, grb
  53. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  54. GRB 060927: pseudo-z from spectral parameters of the prompt emission
  55. GRB 060927: Swift/UVOT Optical Observations
  56. GRB 060927: Early color
  57. GRB 060927: Swift XRT Team refined analysis
  58. GRB 060927 optical limit
  59. GRB 060927, Swift-BAT refined analysis
  60. GRB 060927: Xinglong TNT optical observations
  61. GRB060926: improved redshift
  62. GRB 060927, optical observation
  63. GRB 060927: Possible host galaxy (star?) in the SDSS
  64. GRB 060927 : Kiso optical observation
  65. GRB060927: Faulkes Telescope South observation
  66. GRB 060926: MASTER: first minutes decay
  67. GRB060927 - SDSS Pre-Burst Observations
  68. GRB 060927: optical afterglow confirmation
  69. GRB 060927A: ROTSE-III Detection of Optical Counterpart
  70. Swift XRT boresight
  71. GRB 060927: Swift detection of a burst
  72. GRB060926: VLT redshift
  73. GRB 060926: Swift-UVOT Detections
  74. GRB 060923A: Schedule of Spitzer Space Telescope Observations
  75. GRB 060926: OPTIMA-Burst -- further observations
  76. GRB 060926: Swift XRT refined analysis
  77. GRB 060926, Swift-BAT refined analysis
  78. GRB 060923A: Radio Observations
  79. GRB 060926: MASTER OT alert observation
  80. GRB 060926: RTT150, UVOT afterglow candidate confirmation
  81. GRB 060912A: Redshift of probable host galaxy
  82. GRB 060926: BOOTES-IR observations
  83. GRB 060926: Watcher observations
  84. GRB060926 OPTIMA-Burst optical observation
  85. GRB 060926: MASTER optical observation
  86. GRB 060926: Swift detection of a burst
  87. GRB 060923C, Swift-BAT refined analysis
  88. GRB 060923C: VLA Observation
  89. GRB 060923C: NIR afterglow confirmed
  90. GRB060923C: AROMA optical obsevation
  91. GRB 060923C: Gemini Observations and Afterglow Candidate
  92. GRB 060923C, optical observation
  93. GRB 060923A: Gemini Second Epoch and Afterglow Confirmation
  94. GRB 060923C: VLT J-band observations
  95. GRB060923B: Swift/UVOT upper limits
  96. GRB 060923B: Swift XRT Refined Analysis
  97. GRB 060923C: Swift XRT refined analysis
  98. GRB 060923C, Swift-BAT partial refined analysis
  99. GRB 060923A: Swift XRT refined analysis
  100. GRB 060923C: Keck Observations

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