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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 061028, Swift-BAT refined analysis
  2. GRB 061028: TAROT Calern observatory late optical observations
  3. GRB 061028: TAROT Calern observatory optical observations
  4. GRB 061028: Swift detection of a burst
  5. GRB 061027, Swift refined analysis of a possible burst
  6. GRB 061027: Swift detection of a possible burst
  7. GRB061025: ROTSE-III Confirmation of Optical Counterpart
  8. GRB061025: Swift XRT refined analysis
  9. GRB061025: Swift/UVOT observations
  10. GRB 061019: MITSuME upper limits
  11. GRB 061025: REM observations
  12. GRB 061025: Gemini-S observations
  13. GRB061025: Swift XRT position
  14. GRB 061025: ROTSE-III Optical Limits
  15. GRB 061025: a long GRB detected by INTEGRAL
  16. Swift XRT boresight update
  17. GRB 061021, Swift-BAT Lag analysis
  18. Konus-Wind observation of GRB 061021
  19. GRB 061021 - VLT spectrum without lines
  20. GRB 061021: Swift-XRT refined analysis
  21. GRB 061021: Swift/UVOT Observation
  22. GRB 061021, Swift-BAT refined analysis
  23. GRB 061021: Swift detection of a burst
  24. GRB 061019: Super-LOTIS upper limit
  25. GRB060904b: optical observations
  26. GRB061019: optical observations
  27. GRB061019: optical observations
  28. GRB 061019: SARA upper limit
  29. GRB 061019: dust-scattered X-ray halo detected in Swift/XRT
  30. GRB 060930: MARGE Optical Limits
  31. GRB 061019: Swift/UVOT upper limit
  32. GRB 061019: SMARTS afterglow confirmation
  33. GRB061019: Swift XRT refined analysis
  34. GRB 061019, Swift-BAT refined analysis
  35. GRB 061019: TAROT La Silla observatory optical observations
  36. GRB 061019: REM K-band candidate afterglow
  37. GRB061019: Swift/XRT position
  38. GRB 061019: Swift-BAT detection of a burst
  39. GRB 060825: GORT Observations
  40. GRB 061007: Second Epoch ATCA Radio Observations
  41. GRB 061007: RHESSI Spectral Fit
  42. GRB 061007: Suzaku/WAM observation of the prompt emission
  43. GRB 061006: astrometry-corrected XRT position
  44. Konus-Wind observation of GRB 061007
  45. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  46. GRB 061007: ATCA Radio Observations
  47. GRB061007: Swift UVOT followup observations
  48. GRB 061006: optical afterglow
  49. GRB 061006 : Suzaku/WAM observation of the prompt emission
  50. GRB 061007: OA fading and VLT redshift
  51. GRB 061007: Magellan Spectroscopy
  52. GRB 061007: Correction to GCN 5712
  53. GRB 061007: Swift-BAT refined analysis
  54. GRB 061007: Swift XRT refined analysis
  55. GRB 061006: Swift/UVOT optical observations
  56. Konus-Wind observation of the short hard GRB 061006
  57. GRB 061007 - FTS early brightening and power law decay
  58. GRB 061007 - Faulkes Telescope South Afterglow Confirmation
  59. GRB 061007: Swift detection of a burst with an optical counterpart
  60. GRB 061007: ROTSE-III Detection of Optical Counterpart
  61. GRB 061006: VLT observation
  62. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  63. GRB 061006: Swift-XRT Team Refined Analysis
  64. GRB061006 (Swift 232585) might be a short-hard GRB
  65. GRB 060930: near-IR afterglow candidate retraction
  66. GRB061006: Faulkes Telescope South Observations
  67. GRB 061006: Swift detection of a burst
  68. GRB 061004: Optical afterglow candidate and redshift
  69. GRB 061004: Las Campanas Optical/NIR Observations
  70. GRB061004: Swift/UVOT optical observations
  71. GRB 061004: Swift-XRT Team Refined Analysis
  72. GRB 061004, Swift BAT refined analysis
  73. GRB 061004: Nearby 2MASS Galaxy
  74. GRB 060928: Correction to GCN 5690
  75. GRB 061004: Swift detection of a burst
  76. GRB 060928: 2 pseudo-z from 2 detections spectral parameters
  77. Konus-Wind observation of GRB 060928
  78. GRB 060928: Suzaku/WAM observation of the prompt emission
  79. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  80. GRB 060928: Swift observations
  81. GRB 060928: RHESSI Spectral Fit
  82. IPN triangulation of GRB060928 (long, exceptionally bright)
  83. GRB061002: Swift UVOT followup observations
  84. GRB 060930: near-IR afterglow candidate
  85. GRB 061002: Swift-XRT Team Refined Analysis
  86. VLA observations of GRB 060926
  87. GRB061002 - SDSS Pre-Burst Observations
  88. GRB 061002, Swift-BAT refined analysis
  89. GRB061002: MASTER-VWF-Kislovodsk observations
  90. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  91. GRB 061002: Swift detection of a burst
  92. GRB 060908: Detection of a possible host
  93. GRB 060923A: Probable host galaxy in the R-band
  94. GRB 060807: Detection of a possible host galaxy
  95. GRB 060923A: VLA K-band Observations
  96. GRB060930: Faulkes Telescope South observation
  97. GRB 060930: Xinglong TNT optical observations
  98. GRB 060929: Further XRT Refined Analysis
  99. GRB 060929: Swift/UVOT Optical Observations
  100. GRB 060930: ROTSE-III Optical Limits

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