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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 061019: Swift-BAT detection of a burst
  2. GRB 060825: GORT Observations
  3. GRB 061007: Second Epoch ATCA Radio Observations
  4. GRB 061007: RHESSI Spectral Fit
  5. GRB 061007: Suzaku/WAM observation of the prompt emission
  6. GRB 061006: astrometry-corrected XRT position
  7. Konus-Wind observation of GRB 061007
  8. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  9. GRB 061007: ATCA Radio Observations
  10. GRB061007: Swift UVOT followup observations
  11. GRB 061006: optical afterglow
  12. GRB 061006 : Suzaku/WAM observation of the prompt emission
  13. GRB 061007: OA fading and VLT redshift
  14. GRB 061007: Magellan Spectroscopy
  15. GRB 061007: Correction to GCN 5712
  16. GRB 061007: Swift-BAT refined analysis
  17. GRB 061007: Swift XRT refined analysis
  18. GRB 061006: Swift/UVOT optical observations
  19. Konus-Wind observation of the short hard GRB 061006
  20. GRB 061007 - FTS early brightening and power law decay
  21. GRB 061007 - Faulkes Telescope South Afterglow Confirmation
  22. GRB 061007: Swift detection of a burst with an optical counterpart
  23. GRB 061007: ROTSE-III Detection of Optical Counterpart
  24. GRB 061006: VLT observation
  25. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  26. GRB 061006: Swift-XRT Team Refined Analysis
  27. GRB061006 (Swift 232585) might be a short-hard GRB
  28. GRB 060930: near-IR afterglow candidate retraction
  29. GRB061006: Faulkes Telescope South Observations
  30. GRB 061006: Swift detection of a burst
  31. GRB 061004: Optical afterglow candidate and redshift
  32. GRB 061004: Las Campanas Optical/NIR Observations
  33. GRB061004: Swift/UVOT optical observations
  34. GRB 061004: Swift-XRT Team Refined Analysis
  35. GRB 061004, Swift BAT refined analysis
  36. GRB 061004: Nearby 2MASS Galaxy
  37. GRB 060928: Correction to GCN 5690
  38. GRB 061004: Swift detection of a burst
  39. GRB 060928: 2 pseudo-z from 2 detections spectral parameters
  40. Konus-Wind observation of GRB 060928
  41. GRB 060928: Suzaku/WAM observation of the prompt emission
  42. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  43. GRB 060928: Swift observations
  44. GRB 060928: RHESSI Spectral Fit
  45. IPN triangulation of GRB060928 (long, exceptionally bright)
  46. GRB061002: Swift UVOT followup observations
  47. GRB 060930: near-IR afterglow candidate
  48. GRB 061002: Swift-XRT Team Refined Analysis
  49. VLA observations of GRB 060926
  50. GRB061002 - SDSS Pre-Burst Observations
  51. GRB 061002, Swift-BAT refined analysis
  52. GRB061002: MASTER-VWF-Kislovodsk observations
  53. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  54. GRB 061002: Swift detection of a burst
  55. GRB 060908: Detection of a possible host
  56. GRB 060923A: Probable host galaxy in the R-band
  57. GRB 060807: Detection of a possible host galaxy
  58. GRB 060923A: VLA K-band Observations
  59. GRB060930: Faulkes Telescope South observation
  60. GRB 060930: Xinglong TNT optical observations
  61. GRB 060929: Further XRT Refined Analysis
  62. GRB 060929: Swift/UVOT Optical Observations
  63. GRB 060930: ROTSE-III Optical Limits
  64. GRB 060930: A long X-ray rich GRB detected by INTEGRAL
  65. GRB 060927 : GAO 150cm telescope optical observation
  66. GRB060929: Swift-XRT refined analysis.
  67. GRB 060929, Swift-BAT further refined analysis - late-time flare
  68. GRB 060929: TNG K-band observations
  69. GRB 060929, Swift-BAT refined analysis
  70. GRB060929: Optical limit
  71. GRB 060929: BART observation
  72. GRB 060929: MASTER-VWF-Kislovodsk observations
  73. GRB 060929: BOOTES-IR & OSN observations
  74. Liverpool Telescope observations of GRB 060929
  75. GRB 060929: Swift detection of a burst
  76. GRB060908: optical observations
  77. GRB 060729: An update on the late-time Swift observations
  78. GRB 060927: Spectroscopic redshift z=5.6
  79. IBAS Alert n.3501: not a GRB
  80. IBAS Alert n.3500: not a GRB
  81. GRB060923C: optical limit
  82. GRB060927: optical observations
  83. test of new software, grb
  84. GRB 060926: Swift-UVOT UVW1 Detection Retraction
  85. GRB 060927: pseudo-z from spectral parameters of the prompt emission
  86. GRB 060927: Swift/UVOT Optical Observations
  87. GRB 060927: Early color
  88. GRB 060927: Swift XRT Team refined analysis
  89. GRB 060927 optical limit
  90. GRB 060927, Swift-BAT refined analysis
  91. GRB 060927: Xinglong TNT optical observations
  92. GRB060926: improved redshift
  93. GRB 060927, optical observation
  94. GRB 060927: Possible host galaxy (star?) in the SDSS
  95. GRB 060927 : Kiso optical observation
  96. GRB060927: Faulkes Telescope South observation
  97. GRB 060926: MASTER: first minutes decay
  98. GRB060927 - SDSS Pre-Burst Observations
  99. GRB 060927: optical afterglow confirmation
  100. GRB 060927A: ROTSE-III Detection of Optical Counterpart

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