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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: early Swift XRT analysis results
  2. GRB 050802: Swift/UVOT observations
  3. GRB 050802 : Lulin Optical follow-up observation
  4. GRB 050802: Swift-BAT refined analysis
  5. GRB050801: Optical photometry and decay index
  6. GRB 050802: XRT position
  7. GRB 050802: Swift Gamma-ray Burst
  8. GRB050801: Swift/UVOT Optical and UV detections
  9. GRB 050730: Preliminary Analysis of MIKE Spectrum
  10. GCN 050801: early Swift XRT analysis results
  11. GRB 050801: Swift-BAT refined analysis
  12. GRB 050801, SMARTS optical/IR afterglow observations
  13. GRB 050801, afterglow observations
  14. GRB 050730, corrected photometry and break?
  15. GRB 050801: ROTSE-III Early Afterglow Break
  16. GRB050801: Swift-BAT detection of a burst
  17. GRB050801: GCN XRT position is incorrect
  18. GRB 050801: ROTSE-III Detection of Possible Counterpart
  19. GRB 050730: XRT refined analysis
  20. Correction to GCN Circ 3476 on GRB050525A
  21. GRB 050730: early TAROT optical observations
  22. GRB 050726: PROMPT Rc Observations
  23. GRB 050730: RTT150 optical observations
  24. Swift/UVOT photometry of GRB050730
  25. GRB 050730, spectra and optical photometry
  26. GRB050730: Refined BAT analysis of the Swift-BAT burst
  27. GRB 050730: Swift XRT afterglow observations
  28. GRB 050730 XMM-Newton observation
  29. GRB 050730: PROMPT VRcIc Observations
  30. GRB050730, afterglow observations
  31. GRB050730: confirmation of redshift
  32. GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
  33. GRB 050730, SMARTS optical/IR afterglow observations
  34. GRB 050730 : Planned XMM-Newton observation
  35. GRB050730: Liverpool Telescope optical observations
  36. GRB 050730, optical candidate
  37. GRB050730: Swift-BAT detection of a weak burst
  38. GRB 050713A: Swift XRT extended light curve
  39. GRB 050709: PROMPT Rc Observations
  40. GRB050713b: Maidanak optical observations
  41. GRB 050724: Secure Host Redshift from Keck
  42. GRB 050724: WHT optical observations
  43. GRB050726: Swift UVOT observations
  44. GRB 050724: Chandra Observations of the X-ray Afterglow
  45. GRB050724: Refined Radio Position
  46. GRB050713: analysis of the XMM-Newton observation
  47. GRB 050724, SMARTS optical/IR afterglow observations
  48. GRB 050726, SMARTS optical/IR observations
  49. Swift-BAT trigger 147918 is not a real GRB
  50. GRB 050727: RTT150 optical observations
  51. GRB050724: VLT observations of the variable source
  52. GRB050727: KAIT optical limit
  53. GRB050709: Second Epoch Chandra Observation
  54. GRB 050726: PROMPT Rc Observations
  55. GRB050709: Second Epoch Chandra Observation
  56. GRB 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
  57. GRB050724: Further Radio Observations
  58. GRB 050726: early Swift XRT analysis results
  59. GRB050726: Swift-BAT detection of a weak burst
  60. GRB 050724: Optical Variability in Nearby Galaxy
  61. GRB 050724: J-band observations
  62. GRB 050724: GMOS Imaging and Spectroscopy
  63. GRB 050724: SWIFT XRT refined position
  64. RXTE ASM Detection of GRB050724
  65. GRB050724: Radio Observation
  66. GRB 050724: spectroscopy of object in the XRT error circle
  67. GRB 050724: Optical limit
  68. GRB 050724: optical and near-IR observations
  69. GRB 050724: Optical imaging/astrometry
  70. GRB 050724: RTT150 optical observations
  71. GRB 050724: Swift/UVOT Upper Limit
  72. GRB 050724: early Swift XRT analysis results
  73. GRB 050724 : Lulin early R-band monitoring observations
  74. GRB050724: Refined analysis of the Swift-BAT possible short burst
  75. GRB 050724: possible host galaxy in DSS
  76. GRB050724: a short-burst detected by Swift
  77. Swift-BAT trigger 147325 is not due to a real GRB
  78. GRB050723: XRT distributed coordinates are not related to the burst
  79. GRB 050721: early afterglow light curve
  80. GRB 050721A: Swift-BAT refined analysis
  81. Correction to GCN Circ 3474 on GRB050525A
  82. GRB 050721A: Early Swift XRT analysis results
  83. GRB050721A: optical decay
  84. GRB 050721: optical afterglow confirmed
  85. Swift BAT Trigger 146986 is SWIFT J1753.5-0127
  86. GRB 050721a: Optical Observations
  87. GRB050721A: Swift-BAT detection of a weak burst
  88. GRB 050709: Refined Spectral and Temporal Properties
  89. GRB 050717: PROMPT RcIc Observations
  90. GRB050714b: Radio Observation
  91. GRB050712: Radio Observations
  92. GRB 050714a: Refined XRT analysis and afterglow confirmation
  93. GRB050713a: Radio Observation
  94. Swift-BAT trigger 146731 is not a real GRB
  95. GRB 050712, Tautenburg optical afterglow observations
  96. Swift-BAT detection of a possible GRB
  97. GRB 050714B: VLT R-band observations
  98. GRB 050717: Additional LCO observations
  99. GRB050717
  100. GRB 050716; J-band observations

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