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

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