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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. GRB061102B: Super-LOTIS observations
  2. GRB 061028: Optical R passband observations
  3. GRB 061102B: Swift detection of a possible burst
  4. GRB 061102, Swift-BAT refined analysis
  5. GRB 061102: Swift detection of a burst
  6. GRB 061028: VLA Observation
  7. GRB 061004: Swift/XRT Astrometry Correction
  8. GRB 060801: Swift/XRT Astrometry Correction
  9. GRB 061028: Futher P200 Observations
  10. GRB 061028: MDM Observations
  11. GRB 061028: P200 Observations
  12. GRB 061028: SARA upper limit
  13. GRB 061028: z band imaging
  14. GRB061028: XRT refined analysis
  15. GRB 061028: Swift/UVOT Observations
  16. GRB 061028, Swift-BAT refined analysis
  17. GRB 061028: TAROT Calern observatory late optical observations
  18. GRB 061028: TAROT Calern observatory optical observations
  19. GRB 061028: Swift detection of a burst
  20. GRB 061027, Swift refined analysis of a possible burst
  21. GRB 061027: Swift detection of a possible burst
  22. GRB061025: ROTSE-III Confirmation of Optical Counterpart
  23. GRB061025: Swift XRT refined analysis
  24. GRB061025: Swift/UVOT observations
  25. GRB 061019: MITSuME upper limits
  26. GRB 061025: REM observations
  27. GRB 061025: Gemini-S observations
  28. GRB061025: Swift XRT position
  29. GRB 061025: ROTSE-III Optical Limits
  30. GRB 061025: a long GRB detected by INTEGRAL
  31. Swift XRT boresight update
  32. GRB 061021, Swift-BAT Lag analysis
  33. Konus-Wind observation of GRB 061021
  34. GRB 061021 - VLT spectrum without lines
  35. GRB 061021: Swift-XRT refined analysis
  36. GRB 061021: Swift/UVOT Observation
  37. GRB 061021, Swift-BAT refined analysis
  38. GRB 061021: Swift detection of a burst
  39. GRB 061019: Super-LOTIS upper limit
  40. GRB060904b: optical observations
  41. GRB061019: optical observations
  42. GRB061019: optical observations
  43. GRB 061019: SARA upper limit
  44. GRB 061019: dust-scattered X-ray halo detected in Swift/XRT
  45. GRB 060930: MARGE Optical Limits
  46. GRB 061019: Swift/UVOT upper limit
  47. GRB 061019: SMARTS afterglow confirmation
  48. GRB061019: Swift XRT refined analysis
  49. GRB 061019, Swift-BAT refined analysis
  50. GRB 061019: TAROT La Silla observatory optical observations
  51. GRB 061019: REM K-band candidate afterglow
  52. GRB061019: Swift/XRT position
  53. GRB 061019: Swift-BAT detection of a burst
  54. GRB 060825: GORT Observations
  55. GRB 061007: Second Epoch ATCA Radio Observations
  56. GRB 061007: RHESSI Spectral Fit
  57. GRB 061007: Suzaku/WAM observation of the prompt emission
  58. GRB 061006: astrometry-corrected XRT position
  59. Konus-Wind observation of GRB 061007
  60. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  61. GRB 061007: ATCA Radio Observations
  62. GRB061007: Swift UVOT followup observations
  63. GRB 061006: optical afterglow
  64. GRB 061006 : Suzaku/WAM observation of the prompt emission
  65. GRB 061007: OA fading and VLT redshift
  66. GRB 061007: Magellan Spectroscopy
  67. GRB 061007: Correction to GCN 5712
  68. GRB 061007: Swift-BAT refined analysis
  69. GRB 061007: Swift XRT refined analysis
  70. GRB 061006: Swift/UVOT optical observations
  71. Konus-Wind observation of the short hard GRB 061006
  72. GRB 061007 - FTS early brightening and power law decay
  73. GRB 061007 - Faulkes Telescope South Afterglow Confirmation
  74. GRB 061007: Swift detection of a burst with an optical counterpart
  75. GRB 061007: ROTSE-III Detection of Optical Counterpart
  76. GRB 061006: VLT observation
  77. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  78. GRB 061006: Swift-XRT Team Refined Analysis
  79. GRB061006 (Swift 232585) might be a short-hard GRB
  80. GRB 060930: near-IR afterglow candidate retraction
  81. GRB061006: Faulkes Telescope South Observations
  82. GRB 061006: Swift detection of a burst
  83. GRB 061004: Optical afterglow candidate and redshift
  84. GRB 061004: Las Campanas Optical/NIR Observations
  85. GRB061004: Swift/UVOT optical observations
  86. GRB 061004: Swift-XRT Team Refined Analysis
  87. GRB 061004, Swift BAT refined analysis
  88. GRB 061004: Nearby 2MASS Galaxy
  89. GRB 060928: Correction to GCN 5690
  90. GRB 061004: Swift detection of a burst
  91. GRB 060928: 2 pseudo-z from 2 detections spectral parameters
  92. Konus-Wind observation of GRB 060928
  93. GRB 060928: Suzaku/WAM observation of the prompt emission
  94. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  95. GRB 060928: Swift observations
  96. GRB 060928: RHESSI Spectral Fit
  97. IPN triangulation of GRB060928 (long, exceptionally bright)
  98. GRB061002: Swift UVOT followup observations
  99. GRB 060930: near-IR afterglow candidate
  100. GRB 061002: Swift-XRT Team Refined Analysis

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