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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"

24169 results found.

  1. Swift detection of a long transient (GRB 050714B?)
  2. GRB 050714A: ROTSE-III Optical Limits
  3. GRB 050713A: XRT refined analysis
  4. GRB 050713A: RAPTOR detection of early optical emission
  5. GRB050713B :Swift/UVOT observations
  6. GRB050713b: XRT refined analysis
  7. GRB 050713B: Swift-BAT Refined Analysis
  8. Swift-BAT Trigger 145729 is not a GRB
  9. GRB 050713A: Swift/UVOT observation
  10. GRB 050713A : Swift-BAT Refined Analysis
  11. GRB050713B: Faulkes North Telescope observation
  12. RBO RI observations of GRB 050713A
  13. GRB 050713B
  14. GRB 050713: Swift detection of Bright Burst
  15. GRB 050713A: ROTSE-III Optical Limits
  16. GRB050712: XRT refined analysis
  17. GRB 050712: Swift-BAT Refined Analysis
  18. GRB050712: UVOT candidate optical counterpart
  19. GRB 050712: Swift XRT afterglow position
  20. GRB 050712: Swift detection of a weak burst
  21. GRB050709: A Possible Short-Hard GRB Localized by HETE
  22. GRB 050525a: PROMPT VRcIc Detections
  23. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  24. GRB 050701
  25. GRB 050701, optical observations
  26. GRB 050701: Refined XRT analysis
  27. Swift UVOT observations of GRB 050701
  28. GRB050701: Swift-BAT Refined analysis
  29. GRB 050701: Swift XRT afterglow position
  30. Swift trigger 143708 is really GRB 050701
  31. GRB 050525A: Swift Late-Time Decay Rate
  32. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  33. XRF 050509c: Optical monitoring
  34. Konus-Wind observation of an intermediate burst from SGR 1806-20
  35. GRB 050607 optical decay
  36. Swift/UVOT observations of GRB050607
  37. GRB 050607: PROMPT VRcIc Observations
  38. GRB 050607: RAPTOR-S Early Optical Limits
  39. GRB 050607: MDM Observations
  40. GRB050607,optical observation
  41. GRB 050607 - XRT refined data analysis
  42. GRB050607 optical limit by "Pi of the Sky"
  43. GRB050607: Swift Detection of a long GRB
  44. GRB050607: P60 Observations
  45. GRB 050603: prediction of t_break
  46. Konus-Wind observation of GRB 050603
  47. GRB050603: Fading Afterglow observed by Swift UVOT
  48. GRB 050603: Swift XRT Position
  49. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  50. GRB 050603: Afterglow Identification from LCO
  51. Swift/BAT Detection of GRB050603
  52. GRB 050408: jet break in the XRT light curve
  53. GRB050528, XRT observations
  54. Correction to GCN Circ 3502 on GRB 050528
  55. Swift-BAT GRB 050528: a soft burst
  56. Update on Swift-BAT GRB 050528 (Trigger 130679)
  57. GRB050528: BOOTES optical candidate (retraction)
  58. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  59. GRB050528: BOOTES optical candidate
  60. Possible GRB050528: no candidate from Liverpool Telescope
  61. Swift-BAT detection of possible GRB 050528
  62. GRB 050525B: Swift-BAT observations
  63. GRB050525A,optical observation
  64. GRB050525: Super-LOTIS observations
  65. GRB 050525, spectral lag pseudo-redshift
  66. GRB 050525A: BOOTES simultaneous optical observations
  67. GRB 050525A: Swift-BAT refined analysis
  68. Swift/UVOT UV and optical detections of GRB 050525
  69. Konus-Wind observation of GRB 050525
  70. GRB 050525 - Very Bright, Not Short
  71. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  72. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  73. GRB 050509A: Further I-band imaging
  74. GRB050522,optical observation
  75. GRB050520,optical observation
  76. GRB 050520: VLT/ULTRACAM observations
  77. GRB 050520: BART optical limit
  78. No Swift-BAT Lightcurves in real-time for next 3 weeks
  79. Swift-BAT trigger 122203 is not a real GRB
  80. XRF 050509C: REM NIR and Optical refined analysis
  81. XRF 050509c optical afterglow
  82. GRB050502b: Early Observation
  83. GRB050509b, SDSS pre-burst observations
  84. GRB 050509b: RAPTOR deep, early limits.
  85. GRB 050509b: Swift/UVOT follow-up measurements
  86. GRB050509B: Optical observations at the Very Large Telescope
  87. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  88. GRB 050509a: Swift-BAT refined analysis
  89. GRB 050509c: ROTSE-III Optical Limits
  90. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  91. GRB050509c: REM NIR and Optical observations
  92. Swift UVOT Follow-up Observations of GRB 050509B
  93. GRB 050509B: Swift/XRT refined analysis
  94. GRB050509a: Swift UVOT observations
  95. GRB 050509b: Optical observations
  96. GRB 050509A: Optical observations
  97. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  98. GRB 050509b: optical observations
  99. GRB 050509b: Swift XRT Position
  100. GRB 050509B: ROTSE-III Optical Limits

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