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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 061006: Swift-XRT Team Refined Analysis
  2. GRB061006 (Swift 232585) might be a short-hard GRB
  3. GRB 060930: near-IR afterglow candidate retraction
  4. GRB061006: Faulkes Telescope South Observations
  5. GRB 061006: Swift detection of a burst
  6. GRB 061004: Optical afterglow candidate and redshift
  7. GRB 061004: Las Campanas Optical/NIR Observations
  8. GRB061004: Swift/UVOT optical observations
  9. GRB 061004: Swift-XRT Team Refined Analysis
  10. GRB 061004, Swift BAT refined analysis
  11. GRB 061004: Nearby 2MASS Galaxy
  12. GRB 060928: Correction to GCN 5690
  13. GRB 061004: Swift detection of a burst
  14. GRB 060928: 2 pseudo-z from 2 detections spectral parameters
  15. Konus-Wind observation of GRB 060928
  16. GRB 060928: Suzaku/WAM observation of the prompt emission
  17. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  18. GRB 060928: Swift observations
  19. GRB 060928: RHESSI Spectral Fit
  20. IPN triangulation of GRB060928 (long, exceptionally bright)
  21. GRB061002: Swift UVOT followup observations
  22. GRB 060930: near-IR afterglow candidate
  23. GRB 061002: Swift-XRT Team Refined Analysis
  24. VLA observations of GRB 060926
  25. GRB061002 - SDSS Pre-Burst Observations
  26. GRB 061002, Swift-BAT refined analysis
  27. GRB061002: MASTER-VWF-Kislovodsk observations
  28. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  29. GRB 061002: Swift detection of a burst
  30. GRB 060908: Detection of a possible host
  31. GRB 060923A: Probable host galaxy in the R-band
  32. GRB 060807: Detection of a possible host galaxy
  33. GRB 060923A: VLA K-band Observations
  34. GRB060930: Faulkes Telescope South observation
  35. GRB 060930: Xinglong TNT optical observations
  36. GRB 060929: Further XRT Refined Analysis
  37. GRB 060929: Swift/UVOT Optical Observations
  38. GRB 060930: ROTSE-III Optical Limits
  39. GRB 060930: A long X-ray rich GRB detected by INTEGRAL
  40. GRB 060927 : GAO 150cm telescope optical observation
  41. GRB060929: Swift-XRT refined analysis.
  42. GRB 060929, Swift-BAT further refined analysis - late-time flare
  43. GRB 060929: TNG K-band observations
  44. GRB 060929, Swift-BAT refined analysis
  45. GRB060929: Optical limit
  46. GRB 060929: BART observation
  47. GRB 060929: MASTER-VWF-Kislovodsk observations
  48. GRB 060929: BOOTES-IR & OSN observations
  49. Liverpool Telescope observations of GRB 060929
  50. GRB 060929: Swift detection of a burst
  51. GRB060908: optical observations
  52. GRB 060729: An update on the late-time Swift observations
  53. GRB 060927: Spectroscopic redshift z=5.6
  54. IBAS Alert n.3501: not a GRB
  55. IBAS Alert n.3500: not a GRB
  56. GRB060923C: optical limit
  57. GRB060927: optical observations
  58. test of new software, grb
  59. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  60. GRB 060927: pseudo-z from spectral parameters of the prompt emission
  61. GRB 060927: Swift/UVOT Optical Observations
  62. GRB 060927: Early color
  63. GRB 060927: Swift XRT Team refined analysis
  64. GRB 060927 optical limit
  65. GRB 060927, Swift-BAT refined analysis
  66. GRB 060927: Xinglong TNT optical observations
  67. GRB060926: improved redshift
  68. GRB 060927, optical observation
  69. GRB 060927: Possible host galaxy (star?) in the SDSS
  70. GRB 060927 : Kiso optical observation
  71. GRB060927: Faulkes Telescope South observation
  72. GRB 060926: MASTER: first minutes decay
  73. GRB060927 - SDSS Pre-Burst Observations
  74. GRB 060927: optical afterglow confirmation
  75. GRB 060927A: ROTSE-III Detection of Optical Counterpart
  76. Swift XRT boresight
  77. GRB 060927: Swift detection of a burst
  78. GRB060926: VLT redshift
  79. GRB 060926: Swift-UVOT Detections
  80. GRB 060923A: Schedule of Spitzer Space Telescope Observations
  81. GRB 060926: OPTIMA-Burst -- further observations
  82. GRB 060926: Swift XRT refined analysis
  83. GRB 060926, Swift-BAT refined analysis
  84. GRB 060923A: Radio Observations
  85. GRB 060926: MASTER OT alert observation
  86. GRB 060926: RTT150, UVOT afterglow candidate confirmation
  87. GRB 060912A: Redshift of probable host galaxy
  88. GRB 060926: BOOTES-IR observations
  89. GRB 060926: Watcher observations
  90. GRB060926 OPTIMA-Burst optical observation
  91. GRB 060926: MASTER optical observation
  92. GRB 060926: Swift detection of a burst
  93. GRB 060923C, Swift-BAT refined analysis
  94. GRB 060923C: VLA Observation
  95. GRB 060923C: NIR afterglow confirmed
  96. GRB060923C: AROMA optical obsevation
  97. GRB 060923C: Gemini Observations and Afterglow Candidate
  98. GRB 060923C, optical observation
  99. GRB 060923A: Gemini Second Epoch and Afterglow Confirmation
  100. GRB 060923C: VLT J-band observations

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