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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"

42173 results found.

  1. GRB050803: CrAO optical observations, no OT candidate
  2. Detection of an intermediate burst from SGR 1806-20 on August 8
  3. GRB 050730: WSRT Radio Observations
  4. GRB 050807: ROTSE-III Optical Limits
  5. GRB 050730, optical observation
  6. GRB050805b: CrAO optical limit
  7. GRB050805a : Null detection report
  8. GRB050730, optical observations
  9. GRB050803, optical observations
  10. Retraction of Swift Trigger 149131 (GRB 050805B)
  11. GRB 050805b: OHP optical limits
  12. GRB 050805b: TAROT optical limits
  13. GRB050805b: MASTER optical observations
  14. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  15. GRB050805a: MASTER optical candidat
  16. Swift-BAT trigger 149118 is probably not a GRB
  17. GRB050802: TNG optical observations
  18. GRB050803: Radio Observation
  19. GRB 050803: RTT150 optical observations
  20. GRB050801: Radio Observation
  21. GRB050730: Radio Detection
  22. GRB050803: CrAO optical observations, possible OT candidate
  23. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  24. GRB 050803: Keck Observations
  25. GRB 050803: Swift-BAT refined analysis
  26. GRB 050802.422: Fading of the afterglow and detection of the host
  27. GRB050803: MASTER further analys
  28. GRB 050803, optical observations
  29. GRB 050803: Magellan Observations
  30. GRB 050803: early Swift XRT analysis results
  31. GRB 050803: TAROT optical limits
  32. GRB050803: MASTER optical observations
  33. GRB050802: Tentative absorption redshift
  34. GRB050803: Swift-BAT detection of a very long burst
  35. GCN GRB observation 050713A
  36. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  37. GRB 050802: Swift/UVOT optical and UV detections
  38. GRB050802: CrAO optical observations
  39. GRB050801: Unchanged decay slope
  40. GRB050802 radio non-detection
  41. GRB 050730: OHP optical observations
  42. GRB 050802: early Swift XRT analysis results
  43. GRB 050802: Swift/UVOT observations
  44. GRB 050802 : Lulin Optical follow-up observation
  45. GRB050801: Optical photometry and decay index
  46. GRB 050802: XRT position
  47. GRB 050802: Swift Gamma-ray Burst
  48. GRB050801: Swift/UVOT Optical and UV detections
  49. GRB 050730: Preliminary Analysis of MIKE Spectrum
  50. GCN 050801: early Swift XRT analysis results
  51. GRB 050801, SMARTS optical/IR afterglow observations
  52. GRB 050730, corrected photometry and break?
  53. GRB 050801: ROTSE-III Early Afterglow Break
  54. GRB050801: Swift-BAT detection of a burst
  55. GRB 050801: ROTSE-III Detection of Possible Counterpart
  56. GRB 050730: XRT refined analysis
  57. Correction to GCN Circ 3476 on GRB050525A
  58. GRB 050730: early TAROT optical observations
  59. GRB 050730: RTT150 optical observations
  60. Swift/UVOT photometry of GRB050730
  61. GRB 050730, spectra and optical photometry
  62. GRB050730: Refined BAT analysis of the Swift-BAT burst
  63. GRB 050730: Swift XRT afterglow observations
  64. GRB 050730 XMM-Newton observation
  65. GRB050730, afterglow observations
  66. GRB050730: confirmation of redshift
  67. GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
  68. GRB 050730, SMARTS optical/IR afterglow observations
  69. GRB 050730 : Planned XMM-Newton observation
  70. GRB050730: Liverpool Telescope optical observations
  71. GRB 050730, optical candidate
  72. GRB050730: Swift-BAT detection of a weak burst
  73. GRB 050713A: Swift XRT extended light curve
  74. GRB050713b: Maidanak optical observations
  75. GRB 050724: WHT optical observations
  76. GRB050726: Swift UVOT observations
  77. GRB 050724: Chandra Observations of the X-ray Afterglow
  78. GRB050724: Refined Radio Position
  79. GRB050713: analysis of the XMM-Newton observation
  80. GRB 050724, SMARTS optical/IR afterglow observations
  81. GRB 050726, SMARTS optical/IR observations
  82. Swift-BAT trigger 147918 is not a real GRB
  83. GRB 050727: RTT150 optical observations
  84. GRB050724: VLT observations of the variable source
  85. GRB050727: KAIT optical limit
  86. GRB050709: Second Epoch Chandra Observation
  87. GRB050709: Second Epoch Chandra Observation
  88. GRB 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
  89. GRB050724: Further Radio Observations
  90. GRB 050726: early Swift XRT analysis results
  91. GRB050726: Swift-BAT detection of a weak burst
  92. GRB 050724: Optical Variability in Nearby Galaxy
  93. GRB 050724: J-band observations
  94. GRB 050724: GMOS Imaging and Spectroscopy
  95. GRB 050724: SWIFT XRT refined position
  96. RXTE ASM Detection of GRB050724
  97. GRB050724: Radio Observation
  98. GRB 050724: spectroscopy of object in the XRT error circle
  99. GRB 050724: Optical limit
  100. GRB 050724: optical and near-IR observations

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