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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"

45623 results found.

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

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