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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 050802: Swift/UVOT optical and UV detections
  2. GRB050802: CrAO optical observations
  3. GRB050801: Unchanged decay slope
  4. GRB050802 radio non-detection
  5. GRB 050730: OHP optical observations
  6. GRB 050802: early Swift XRT analysis results
  7. GRB 050802: Swift/UVOT observations
  8. GRB 050802 : Lulin Optical follow-up observation
  9. GRB 050802: Swift-BAT refined analysis
  10. GRB050801: Optical photometry and decay index
  11. GRB 050802: XRT position
  12. GRB 050802: Swift Gamma-ray Burst
  13. GRB050801: Swift/UVOT Optical and UV detections
  14. GRB 050730: Preliminary Analysis of MIKE Spectrum
  15. GCN 050801: early Swift XRT analysis results
  16. GRB 050801: Swift-BAT refined analysis
  17. GRB 050801, SMARTS optical/IR afterglow observations
  18. GRB 050801, afterglow observations
  19. GRB 050730, corrected photometry and break?
  20. GRB 050801: ROTSE-III Early Afterglow Break
  21. GRB050801: Swift-BAT detection of a burst
  22. GRB050801: GCN XRT position is incorrect
  23. GRB 050801: ROTSE-III Detection of Possible Counterpart
  24. GRB 050730: XRT refined analysis
  25. Correction to GCN Circ 3476 on GRB050525A
  26. GRB 050730: early TAROT optical observations
  27. GRB 050726: PROMPT Rc Observations
  28. GRB 050730: RTT150 optical observations
  29. Swift/UVOT photometry of GRB050730
  30. GRB 050730, spectra and optical photometry
  31. GRB050730: Refined BAT analysis of the Swift-BAT burst
  32. GRB 050730: Swift XRT afterglow observations
  33. GRB 050730 XMM-Newton observation
  34. GRB 050730: PROMPT VRcIc Observations
  35. GRB050730, afterglow observations
  36. GRB050730: confirmation of redshift
  37. GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
  38. GRB 050730, SMARTS optical/IR afterglow observations
  39. GRB 050730 : Planned XMM-Newton observation
  40. GRB050730: Liverpool Telescope optical observations
  41. GRB 050730, optical candidate
  42. GRB050730: Swift-BAT detection of a weak burst
  43. GRB 050713A: Swift XRT extended light curve
  44. GRB 050709: PROMPT Rc Observations
  45. GRB050713b: Maidanak optical observations
  46. GRB 050724: Secure Host Redshift from Keck
  47. GRB 050724: WHT optical observations
  48. GRB050726: Swift UVOT observations
  49. GRB 050724: Chandra Observations of the X-ray Afterglow
  50. GRB050724: Refined Radio Position
  51. GRB050713: analysis of the XMM-Newton observation
  52. GRB 050724, SMARTS optical/IR afterglow observations
  53. GRB 050726, SMARTS optical/IR observations
  54. Swift-BAT trigger 147918 is not a real GRB
  55. GRB 050727: RTT150 optical observations
  56. GRB050724: VLT observations of the variable source
  57. GRB050727: KAIT optical limit
  58. GRB050709: Second Epoch Chandra Observation
  59. GRB 050726: PROMPT Rc Observations
  60. GRB050709: Second Epoch Chandra Observation
  61. GRB 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
  62. GRB050724: Further Radio Observations
  63. GRB 050726: early Swift XRT analysis results
  64. GRB050726: Swift-BAT detection of a weak burst
  65. GRB 050724: Optical Variability in Nearby Galaxy
  66. GRB 050724: J-band observations
  67. GRB 050724: GMOS Imaging and Spectroscopy
  68. GRB 050724: SWIFT XRT refined position
  69. RXTE ASM Detection of GRB050724
  70. GRB050724: Radio Observation
  71. GRB 050724: spectroscopy of object in the XRT error circle
  72. GRB 050724: Optical limit
  73. GRB 050724: optical and near-IR observations
  74. GRB 050724: Optical imaging/astrometry
  75. GRB 050724: RTT150 optical observations
  76. GRB 050724: Swift/UVOT Upper Limit
  77. GRB 050724: early Swift XRT analysis results
  78. GRB 050724 : Lulin early R-band monitoring observations
  79. GRB050724: Refined analysis of the Swift-BAT possible short burst
  80. GRB 050724: possible host galaxy in DSS
  81. GRB050724: a short-burst detected by Swift
  82. Swift-BAT trigger 147325 is not due to a real GRB
  83. GRB050723: XRT distributed coordinates are not related to the burst
  84. GRB 050721: early afterglow light curve
  85. GRB 050721A: Swift-BAT refined analysis
  86. Correction to GCN Circ 3474 on GRB050525A
  87. GRB 050721A: Early Swift XRT analysis results
  88. GRB050721A: optical decay
  89. GRB 050721: optical afterglow confirmed
  90. Swift BAT Trigger 146986 is SWIFT J1753.5-0127
  91. GRB 050721a: Optical Observations
  92. GRB050721A: Swift-BAT detection of a weak burst
  93. GRB 050709: Refined Spectral and Temporal Properties
  94. GRB 050717: PROMPT RcIc Observations
  95. GRB050714b: Radio Observation
  96. GRB050712: Radio Observations
  97. GRB 050714a: Refined XRT analysis and afterglow confirmation
  98. GRB050713a: Radio Observation
  99. Swift-BAT trigger 146731 is not a real GRB
  100. GRB 050712, Tautenburg optical afterglow observations

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