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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"

42175 results found.

  1. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  2. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  3. GRB050803: CrAO optical observations, no OT candidate
  4. Detection of an intermediate burst from SGR 1806-20 on August 8
  5. GRB 050730: WSRT Radio Observations
  6. GRB 050807: ROTSE-III Optical Limits
  7. GRB 050730, optical observation
  8. GRB050805b: CrAO optical limit
  9. GRB050805a : Null detection report
  10. GRB050730, optical observations
  11. GRB050803, optical observations
  12. Retraction of Swift Trigger 149131 (GRB 050805B)
  13. GRB 050805b: OHP optical limits
  14. GRB 050805b: TAROT optical limits
  15. GRB050805b: MASTER optical observations
  16. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  17. GRB050805a: MASTER optical candidat
  18. Swift-BAT trigger 149118 is probably not a GRB
  19. GRB050802: TNG optical observations
  20. GRB050803: Radio Observation
  21. GRB 050803: RTT150 optical observations
  22. GRB050801: Radio Observation
  23. GRB050730: Radio Detection
  24. GRB050803: CrAO optical observations, possible OT candidate
  25. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  26. GRB 050803: Keck Observations
  27. GRB 050803: Swift-BAT refined analysis
  28. GRB 050802.422: Fading of the afterglow and detection of the host
  29. GRB050803: MASTER further analys
  30. GRB 050803, optical observations
  31. GRB 050803: Magellan Observations
  32. GRB 050803: early Swift XRT analysis results
  33. GRB 050803: TAROT optical limits
  34. GRB050803: MASTER optical observations
  35. GRB050802: Tentative absorption redshift
  36. GRB050803: Swift-BAT detection of a very long burst
  37. GCN GRB observation 050713A
  38. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  39. GRB 050802: Swift/UVOT optical and UV detections
  40. GRB050802: CrAO optical observations
  41. GRB050801: Unchanged decay slope
  42. GRB050802 radio non-detection
  43. GRB 050730: OHP optical observations
  44. GRB 050802: early Swift XRT analysis results
  45. GRB 050802: Swift/UVOT observations
  46. GRB 050802 : Lulin Optical follow-up observation
  47. GRB050801: Optical photometry and decay index
  48. GRB 050802: XRT position
  49. GRB 050802: Swift Gamma-ray Burst
  50. GRB050801: Swift/UVOT Optical and UV detections
  51. GRB 050730: Preliminary Analysis of MIKE Spectrum
  52. GCN 050801: early Swift XRT analysis results
  53. GRB 050801, SMARTS optical/IR afterglow observations
  54. GRB 050730, corrected photometry and break?
  55. GRB 050801: ROTSE-III Early Afterglow Break
  56. GRB050801: Swift-BAT detection of a burst
  57. GRB 050801: ROTSE-III Detection of Possible Counterpart
  58. GRB 050730: XRT refined analysis
  59. Correction to GCN Circ 3476 on GRB050525A
  60. GRB 050730: early TAROT optical observations
  61. GRB 050730: RTT150 optical observations
  62. Swift/UVOT photometry of GRB050730
  63. GRB 050730, spectra and optical photometry
  64. GRB050730: Refined BAT analysis of the Swift-BAT burst
  65. GRB 050730: Swift XRT afterglow observations
  66. GRB 050730 XMM-Newton observation
  67. GRB050730, afterglow observations
  68. GRB050730: confirmation of redshift
  69. GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
  70. GRB 050730, SMARTS optical/IR afterglow observations
  71. GRB 050730 : Planned XMM-Newton observation
  72. GRB050730: Liverpool Telescope optical observations
  73. GRB 050730, optical candidate
  74. GRB050730: Swift-BAT detection of a weak burst
  75. GRB 050713A: Swift XRT extended light curve
  76. GRB050713b: Maidanak optical observations
  77. GRB 050724: WHT optical observations
  78. GRB050726: Swift UVOT observations
  79. GRB 050724: Chandra Observations of the X-ray Afterglow
  80. GRB050724: Refined Radio Position
  81. GRB050713: analysis of the XMM-Newton observation
  82. GRB 050724, SMARTS optical/IR afterglow observations
  83. GRB 050726, SMARTS optical/IR observations
  84. Swift-BAT trigger 147918 is not a real GRB
  85. GRB 050727: RTT150 optical observations
  86. GRB050724: VLT observations of the variable source
  87. GRB050727: KAIT optical limit
  88. GRB050709: Second Epoch Chandra Observation
  89. GRB050709: Second Epoch Chandra Observation
  90. GRB 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
  91. GRB050724: Further Radio Observations
  92. GRB 050726: early Swift XRT analysis results
  93. GRB050726: Swift-BAT detection of a weak burst
  94. GRB 050724: Optical Variability in Nearby Galaxy
  95. GRB 050724: J-band observations
  96. GRB 050724: GMOS Imaging and Spectroscopy
  97. GRB 050724: SWIFT XRT refined position
  98. RXTE ASM Detection of GRB050724
  99. GRB050724: Radio Observation
  100. GRB 050724: spectroscopy of object in the XRT error circle

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