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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"

37518 results found.

  1. GCN GRB observation 050713A
  2. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  3. GRB 050802: Swift/UVOT optical and UV detections
  4. GRB050802: CrAO optical observations
  5. GRB050801: Unchanged decay slope
  6. GRB 050730: OHP optical observations
  7. GRB 050802: early Swift XRT analysis results
  8. GRB 050802: Swift/UVOT observations
  9. GRB 050802 : Lulin Optical follow-up observation
  10. GRB 050802: Swift-BAT refined analysis
  11. GRB050801: Optical photometry and decay index
  12. GRB 050802: XRT position
  13. GRB 050802: Swift Gamma-ray Burst
  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. GRB 050801: ROTSE-III Detection of Possible Counterpart
  23. GRB 050730: XRT refined analysis
  24. Correction to GCN Circ 3476 on GRB050525A
  25. GRB 050730: early TAROT optical observations
  26. GRB 050726: PROMPT Rc Observations
  27. GRB 050730: RTT150 optical observations
  28. GRB 050730, spectra and optical photometry
  29. GRB050730: Refined BAT analysis of the Swift-BAT burst
  30. GRB 050730: Swift XRT afterglow observations
  31. GRB 050730 XMM-Newton observation
  32. GRB 050730: PROMPT VRcIc Observations
  33. GRB050730, afterglow observations
  34. GRB050730: confirmation of redshift
  35. GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
  36. GRB 050730, SMARTS optical/IR afterglow observations
  37. GRB 050730 : Planned XMM-Newton observation
  38. GRB050730: Liverpool Telescope optical observations
  39. GRB 050730, optical candidate
  40. GRB050730: Swift-BAT detection of a weak burst
  41. GRB 050713A: Swift XRT extended light curve
  42. GRB 050709: PROMPT Rc Observations
  43. GRB050713b: Maidanak optical observations
  44. GRB 050724: Secure Host Redshift from Keck
  45. GRB 050724: WHT optical observations
  46. GRB 050724: Chandra Observations of the X-ray Afterglow
  47. GRB050713: analysis of the XMM-Newton observation
  48. GRB 050724, SMARTS optical/IR afterglow observations
  49. GRB 050726, SMARTS optical/IR observations
  50. Swift-BAT trigger 147918 is not a real GRB
  51. GRB 050727: RTT150 optical observations
  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. GRB 050726: early Swift XRT analysis results
  58. GRB 050724: Optical Variability in Nearby Galaxy
  59. GRB 050724: J-band observations
  60. GRB 050724: GMOS Imaging and Spectroscopy
  61. GRB 050724: SWIFT XRT refined position
  62. GRB 050724: spectroscopy of object in the XRT error circle
  63. GRB 050724: Optical limit
  64. GRB 050724: optical and near-IR observations
  65. GRB 050724: Optical imaging/astrometry
  66. GRB 050724: RTT150 optical observations
  67. GRB 050724: Swift/UVOT Upper Limit
  68. GRB 050724: early Swift XRT analysis results
  69. GRB 050724 : Lulin early R-band monitoring observations
  70. GRB050724: Refined analysis of the Swift-BAT possible short burst
  71. GRB 050724: possible host galaxy in DSS
  72. Swift-BAT trigger 147325 is not due to a real GRB
  73. GRB050723: XRT distributed coordinates are not related to the burst
  74. GRB 050721: early afterglow light curve
  75. GRB 050721A: Swift-BAT refined analysis
  76. Correction to GCN Circ 3474 on GRB050525A
  77. GRB 050721A: Early Swift XRT analysis results
  78. GRB050721A: optical decay
  79. GRB 050721: optical afterglow confirmed
  80. Swift BAT Trigger 146986 is SWIFT J1753.5-0127
  81. GRB 050721a: Optical Observations
  82. GRB 050709: Refined Spectral and Temporal Properties
  83. GRB 050717: PROMPT RcIc Observations
  84. GRB 050714a: Refined XRT analysis and afterglow confirmation
  85. Swift-BAT trigger 146731 is not a real GRB
  86. GRB 050712, Tautenburg optical afterglow observations
  87. Swift-BAT detection of a possible GRB
  88. GRB 050714B: VLT R-band observations
  89. GRB 050717: Additional LCO observations
  90. GRB050717
  91. GRB 050716; J-band observations
  92. Konus-Wind observation of GRB 050717
  93. GRB 050717: LCO near-IR observations
  94. Swift/UVOT Observations of GRB 050717
  95. GRB 050717: Swift-BAT refined analysis
  96. GRB 050717: Refined XRT analysis.
  97. GRB050712: optical limits
  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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