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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. GRB061025: Swift XRT refined analysis
  2. GRB061025: Swift/UVOT observations
  3. GRB 061019: MITSuME upper limits
  4. GRB 061025: REM observations
  5. GRB 061025: Gemini-S observations
  6. GRB061025: Swift XRT position
  7. GRB 061025: ROTSE-III Optical Limits
  8. GRB 061025: a long GRB detected by INTEGRAL
  9. Swift XRT boresight update
  10. GRB 061021, Swift-BAT Lag analysis
  11. Konus-Wind observation of GRB 061021
  12. GRB 061021 - VLT spectrum without lines
  13. GRB 061021: Swift-XRT refined analysis
  14. GRB 061021: Swift/UVOT Observation
  15. GRB 061021, Swift-BAT refined analysis
  16. GRB 061021: Swift detection of a burst
  17. GRB 061019: Super-LOTIS upper limit
  18. GRB060904b: optical observations
  19. GRB061019: optical observations
  20. GRB061019: optical observations
  21. GRB 061019: SARA upper limit
  22. GRB 061019: dust-scattered X-ray halo detected in Swift/XRT
  23. GRB 060930: MARGE Optical Limits
  24. GRB 061019: Swift/UVOT upper limit
  25. GRB 061019: SMARTS afterglow confirmation
  26. GRB061019: Swift XRT refined analysis
  27. GRB 061019, Swift-BAT refined analysis
  28. GRB 061019: TAROT La Silla observatory optical observations
  29. GRB 061019: REM K-band candidate afterglow
  30. GRB061019: Swift/XRT position
  31. GRB 061019: Swift-BAT detection of a burst
  32. GRB 060825: GORT Observations
  33. GRB 061007: Second Epoch ATCA Radio Observations
  34. GRB 061007: RHESSI Spectral Fit
  35. GRB 061007: Suzaku/WAM observation of the prompt emission
  36. GRB 061006: astrometry-corrected XRT position
  37. Konus-Wind observation of GRB 061007
  38. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  39. GRB 061007: ATCA Radio Observations
  40. GRB061007: Swift UVOT followup observations
  41. GRB 061006: optical afterglow
  42. GRB 061006 : Suzaku/WAM observation of the prompt emission
  43. GRB 061007: OA fading and VLT redshift
  44. GRB 061007: Magellan Spectroscopy
  45. GRB 061007: Correction to GCN 5712
  46. GRB 061007: Swift-BAT refined analysis
  47. GRB 061007: Swift XRT refined analysis
  48. GRB 061006: Swift/UVOT optical observations
  49. Konus-Wind observation of the short hard GRB 061006
  50. GRB 061007 - FTS early brightening and power law decay
  51. GRB 061007 - Faulkes Telescope South Afterglow Confirmation
  52. GRB 061007: Swift detection of a burst with an optical counterpart
  53. GRB 061007: ROTSE-III Detection of Optical Counterpart
  54. GRB 061006: VLT observation
  55. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  56. GRB 061006: Swift-XRT Team Refined Analysis
  57. GRB061006 (Swift 232585) might be a short-hard GRB
  58. GRB 060930: near-IR afterglow candidate retraction
  59. GRB061006: Faulkes Telescope South Observations
  60. GRB 061006: Swift detection of a burst
  61. GRB 061004: Optical afterglow candidate and redshift
  62. GRB 061004: Las Campanas Optical/NIR Observations
  63. GRB061004: Swift/UVOT optical observations
  64. GRB 061004: Swift-XRT Team Refined Analysis
  65. GRB 061004, Swift BAT refined analysis
  66. GRB 061004: Nearby 2MASS Galaxy
  67. GRB 060928: Correction to GCN 5690
  68. GRB 061004: Swift detection of a burst
  69. GRB 060928: 2 pseudo-z from 2 detections spectral parameters
  70. Konus-Wind observation of GRB 060928
  71. GRB 060928: Suzaku/WAM observation of the prompt emission
  72. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  73. GRB 060928: Swift observations
  74. GRB 060928: RHESSI Spectral Fit
  75. IPN triangulation of GRB060928 (long, exceptionally bright)
  76. GRB061002: Swift UVOT followup observations
  77. GRB 060930: near-IR afterglow candidate
  78. GRB 061002: Swift-XRT Team Refined Analysis
  79. VLA observations of GRB 060926
  80. GRB061002 - SDSS Pre-Burst Observations
  81. GRB 061002, Swift-BAT refined analysis
  82. GRB061002: MASTER-VWF-Kislovodsk observations
  83. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  84. GRB 061002: Swift detection of a burst
  85. GRB 060908: Detection of a possible host
  86. GRB 060923A: Probable host galaxy in the R-band
  87. GRB 060807: Detection of a possible host galaxy
  88. GRB 060923A: VLA K-band Observations
  89. GRB060930: Faulkes Telescope South observation
  90. GRB 060930: Xinglong TNT optical observations
  91. GRB 060929: Further XRT Refined Analysis
  92. GRB 060929: Swift/UVOT Optical Observations
  93. GRB 060930: ROTSE-III Optical Limits
  94. GRB 060930: A long X-ray rich GRB detected by INTEGRAL
  95. GRB 060927 : GAO 150cm telescope optical observation
  96. GRB060929: Swift-XRT refined analysis.
  97. GRB 060929, Swift-BAT further refined analysis - late-time flare
  98. GRB 060929: TNG K-band observations
  99. GRB 060929, Swift-BAT refined analysis
  100. GRB060929: Optical limit

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