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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 detection of a burst
  2. GRB 061027, Swift refined analysis of a possible burst
  3. GRB 061027: Swift detection of a possible burst
  4. GRB061025: ROTSE-III Confirmation of Optical Counterpart
  5. GRB061025: Swift XRT refined analysis
  6. GRB061025: Swift/UVOT observations
  7. GRB 061019: MITSuME upper limits
  8. GRB 061025: REM observations
  9. GRB 061025: Gemini-S observations
  10. GRB061025: Swift XRT position
  11. GRB 061025: ROTSE-III Optical Limits
  12. GRB 061025: a long GRB detected by INTEGRAL
  13. Swift XRT boresight update
  14. GRB 061021, Swift-BAT Lag analysis
  15. Konus-Wind observation of GRB 061021
  16. GRB 061021 - VLT spectrum without lines
  17. GRB 061021: Swift-XRT refined analysis
  18. GRB 061021: Swift/UVOT Observation
  19. GRB 061021, Swift-BAT refined analysis
  20. GRB 061021: Swift detection of a burst
  21. GRB 061019: Super-LOTIS upper limit
  22. GRB060904b: optical observations
  23. GRB061019: optical observations
  24. GRB061019: optical observations
  25. GRB 061019: SARA upper limit
  26. GRB 061019: dust-scattered X-ray halo detected in Swift/XRT
  27. GRB 060930: MARGE Optical Limits
  28. GRB 061019: Swift/UVOT upper limit
  29. GRB 061019: SMARTS afterglow confirmation
  30. GRB061019: Swift XRT refined analysis
  31. GRB 061019, Swift-BAT refined analysis
  32. GRB 061019: TAROT La Silla observatory optical observations
  33. GRB 061019: REM K-band candidate afterglow
  34. GRB061019: Swift/XRT position
  35. GRB 061019: Swift-BAT detection of a burst
  36. GRB 060825: GORT Observations
  37. GRB 061007: Second Epoch ATCA Radio Observations
  38. GRB 061007: RHESSI Spectral Fit
  39. GRB 061007: Suzaku/WAM observation of the prompt emission
  40. GRB 061006: astrometry-corrected XRT position
  41. Konus-Wind observation of GRB 061007
  42. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  43. GRB 061007: ATCA Radio Observations
  44. GRB061007: Swift UVOT followup observations
  45. GRB 061006: optical afterglow
  46. GRB 061006 : Suzaku/WAM observation of the prompt emission
  47. GRB 061007: OA fading and VLT redshift
  48. GRB 061007: Magellan Spectroscopy
  49. GRB 061007: Correction to GCN 5712
  50. GRB 061007: Swift-BAT refined analysis
  51. GRB 061007: Swift XRT refined analysis
  52. GRB 061006: Swift/UVOT optical observations
  53. Konus-Wind observation of the short hard GRB 061006
  54. GRB 061007 - FTS early brightening and power law decay
  55. GRB 061007 - Faulkes Telescope South Afterglow Confirmation
  56. GRB 061007: Swift detection of a burst with an optical counterpart
  57. GRB 061007: ROTSE-III Detection of Optical Counterpart
  58. GRB 061006: VLT observation
  59. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  60. GRB 061006: Swift-XRT Team Refined Analysis
  61. GRB061006 (Swift 232585) might be a short-hard GRB
  62. GRB 060930: near-IR afterglow candidate retraction
  63. GRB061006: Faulkes Telescope South Observations
  64. GRB 061006: Swift detection of a burst
  65. GRB 061004: Optical afterglow candidate and redshift
  66. GRB 061004: Las Campanas Optical/NIR Observations
  67. GRB061004: Swift/UVOT optical observations
  68. GRB 061004: Swift-XRT Team Refined Analysis
  69. GRB 061004, Swift BAT refined analysis
  70. GRB 061004: Nearby 2MASS Galaxy
  71. GRB 060928: Correction to GCN 5690
  72. GRB 061004: Swift detection of a burst
  73. GRB 060928: 2 pseudo-z from 2 detections spectral parameters
  74. Konus-Wind observation of GRB 060928
  75. GRB 060928: Suzaku/WAM observation of the prompt emission
  76. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  77. GRB 060928: Swift observations
  78. GRB 060928: RHESSI Spectral Fit
  79. IPN triangulation of GRB060928 (long, exceptionally bright)
  80. GRB061002: Swift UVOT followup observations
  81. GRB 060930: near-IR afterglow candidate
  82. GRB 061002: Swift-XRT Team Refined Analysis
  83. VLA observations of GRB 060926
  84. GRB061002 - SDSS Pre-Burst Observations
  85. GRB 061002, Swift-BAT refined analysis
  86. GRB061002: MASTER-VWF-Kislovodsk observations
  87. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  88. GRB 061002: Swift detection of a burst
  89. GRB 060908: Detection of a possible host
  90. GRB 060923A: Probable host galaxy in the R-band
  91. GRB 060807: Detection of a possible host galaxy
  92. GRB 060923A: VLA K-band Observations
  93. GRB060930: Faulkes Telescope South observation
  94. GRB 060930: Xinglong TNT optical observations
  95. GRB 060929: Further XRT Refined Analysis
  96. GRB 060929: Swift/UVOT Optical Observations
  97. GRB 060930: ROTSE-III Optical Limits
  98. GRB 060930: A long X-ray rich GRB detected by INTEGRAL
  99. GRB 060927 : GAO 150cm telescope optical observation
  100. GRB060929: Swift-XRT refined analysis.

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