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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. Swift XRT boresight update
  2. GRB 061021, Swift-BAT Lag analysis
  3. Konus-Wind observation of GRB 061021
  4. GRB 061021 - VLT spectrum without lines
  5. GRB 061021: Swift-XRT refined analysis
  6. GRB 061021: Swift/UVOT Observation
  7. GRB 061021, Swift-BAT refined analysis
  8. GRB 061021: Swift detection of a burst
  9. GRB 061019: Super-LOTIS upper limit
  10. GRB060904b: optical observations
  11. GRB061019: optical observations
  12. GRB061019: optical observations
  13. GRB 061019: SARA upper limit
  14. GRB 061019: dust-scattered X-ray halo detected in Swift/XRT
  15. GRB 060930: MARGE Optical Limits
  16. GRB 061019: Swift/UVOT upper limit
  17. GRB 061019: SMARTS afterglow confirmation
  18. GRB061019: Swift XRT refined analysis
  19. GRB 061019, Swift-BAT refined analysis
  20. GRB 061019: TAROT La Silla observatory optical observations
  21. GRB 061019: REM K-band candidate afterglow
  22. GRB061019: Swift/XRT position
  23. GRB 061019: Swift-BAT detection of a burst
  24. GRB 060825: GORT Observations
  25. GRB 061007: Second Epoch ATCA Radio Observations
  26. GRB 061007: RHESSI Spectral Fit
  27. GRB 061007: Suzaku/WAM observation of the prompt emission
  28. GRB 061006: astrometry-corrected XRT position
  29. Konus-Wind observation of GRB 061007
  30. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  31. GRB 061007: ATCA Radio Observations
  32. GRB061007: Swift UVOT followup observations
  33. GRB 061006: optical afterglow
  34. GRB 061006 : Suzaku/WAM observation of the prompt emission
  35. GRB 061007: OA fading and VLT redshift
  36. GRB 061007: Magellan Spectroscopy
  37. GRB 061007: Correction to GCN 5712
  38. GRB 061007: Swift-BAT refined analysis
  39. GRB 061007: Swift XRT refined analysis
  40. GRB 061006: Swift/UVOT optical observations
  41. Konus-Wind observation of the short hard GRB 061006
  42. GRB 061007 - FTS early brightening and power law decay
  43. GRB 061007 - Faulkes Telescope South Afterglow Confirmation
  44. GRB 061007: Swift detection of a burst with an optical counterpart
  45. GRB 061007: ROTSE-III Detection of Optical Counterpart
  46. GRB 061006: VLT observation
  47. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  48. GRB 061006: Swift-XRT Team Refined Analysis
  49. GRB061006 (Swift 232585) might be a short-hard GRB
  50. GRB 060930: near-IR afterglow candidate retraction
  51. GRB061006: Faulkes Telescope South Observations
  52. GRB 061006: Swift detection of a burst
  53. GRB 061004: Optical afterglow candidate and redshift
  54. GRB 061004: Las Campanas Optical/NIR Observations
  55. GRB061004: Swift/UVOT optical observations
  56. GRB 061004: Swift-XRT Team Refined Analysis
  57. GRB 061004, Swift BAT refined analysis
  58. GRB 061004: Nearby 2MASS Galaxy
  59. GRB 060928: Correction to GCN 5690
  60. GRB 061004: Swift detection of a burst
  61. GRB 060928: 2 pseudo-z from 2 detections spectral parameters
  62. Konus-Wind observation of GRB 060928
  63. GRB 060928: Suzaku/WAM observation of the prompt emission
  64. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  65. GRB 060928: Swift observations
  66. GRB 060928: RHESSI Spectral Fit
  67. IPN triangulation of GRB060928 (long, exceptionally bright)
  68. GRB061002: Swift UVOT followup observations
  69. GRB 060930: near-IR afterglow candidate
  70. GRB 061002: Swift-XRT Team Refined Analysis
  71. VLA observations of GRB 060926
  72. GRB061002 - SDSS Pre-Burst Observations
  73. GRB 061002, Swift-BAT refined analysis
  74. GRB061002: MASTER-VWF-Kislovodsk observations
  75. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  76. GRB 061002: Swift detection of a burst
  77. GRB 060908: Detection of a possible host
  78. GRB 060923A: Probable host galaxy in the R-band
  79. GRB 060807: Detection of a possible host galaxy
  80. GRB 060923A: VLA K-band Observations
  81. GRB060930: Faulkes Telescope South observation
  82. GRB 060930: Xinglong TNT optical observations
  83. GRB 060929: Further XRT Refined Analysis
  84. GRB 060929: Swift/UVOT Optical Observations
  85. GRB 060930: ROTSE-III Optical Limits
  86. GRB 060930: A long X-ray rich GRB detected by INTEGRAL
  87. GRB 060927 : GAO 150cm telescope optical observation
  88. GRB060929: Swift-XRT refined analysis.
  89. GRB 060929, Swift-BAT further refined analysis - late-time flare
  90. GRB 060929: TNG K-band observations
  91. GRB 060929, Swift-BAT refined analysis
  92. GRB060929: Optical limit
  93. GRB 060929: BART observation
  94. GRB 060929: MASTER-VWF-Kislovodsk observations
  95. GRB 060929: BOOTES-IR & OSN observations
  96. Liverpool Telescope observations of GRB 060929
  97. GRB 060929: Swift detection of a burst
  98. GRB060908: optical observations
  99. GRB 060729: An update on the late-time Swift observations
  100. GRB 060927: Spectroscopic redshift z=5.6

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