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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"

23404 results found.

  1. GRB 050712: Swift detection of a weak burst
  2. GRB 050709: LCO40 Observations
  3. PROMPT Rc Observations of GRB 050709
  4. GRB 050525a: PROMPT VRcIc Detections
  5. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  6. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  7. GRB 050626: Swift XRT observations
  8. GRB 050408: ARC 3.5-meter NIR Observations
  9. Swift UVOT observations of GRB 050701
  10. Swift trigger 143708 is really GRB 050701
  11. GRB 050607, radio observations
  12. GRB050525a: HST Observations
  13. XRF 050509c: Optical monitoring
  14. XRF050509c: Radio Detection
  15. GRB 050607 optical decay
  16. GRB050607: refined analysis of prompt REM observations
  17. Swift/UVOT observations of GRB050607
  18. GRB 050607: PROMPT VRcIc Observations
  19. GRB 050607: Optical decay and spectral slope
  20. GRB050607,optical observation
  21. GRB 050607 - XRT refined data analysis
  22. Optical Afterglow of GRB 050607
  23. GRB050607: Swift Detection of a long GRB
  24. GRB050607: prompt REM observations
  25. GRB 050603: prediction of t_break
  26. Limits on a SN in the field of GRB 050509b
  27. Konus-Wind observation of GRB 050603
  28. GRB050603: Fading Afterglow observed by Swift UVOT
  29. GRB050603, submillimetre observations
  30. GRB050603: Radio Detection
  31. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  32. GRB 050603: INTEGRAL shows it is not a short GRB
  33. Swift/BAT Detection of GRB050603
  34. GRB 050525a, infrared observations
  35. GRB050528, XRT observations
  36. GRB050528: updated Liverpool Telescope limits
  37. Swift-BAT GRB 050528: a soft burst
  38. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  39. Possible GRB050528: no candidate from Liverpool Telescope
  40. Swift-BAT detection of possible GRB 050528
  41. GRB050525a: Radio Observations
  42. GRB 050509b: refined XRT/Chandra afterglow position analysis
  43. GRB 050525: RTT150, Optical observations
  44. GRB 050525a: SARA Observations
  45. GRB 050525B: Swift-BAT observations
  46. GRB 050525: MITSuME Optical Observation in VRI
  47. GRB050525A,optical observation
  48. GRB050525: Super-LOTIS observations
  49. GRB050306: optical afterglow not confirmed
  50. GRB 050525: BART optical observation
  51. GRB 050525A: BOOTES simultaneous optical observations
  52. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  53. Konus-Wind observation of GRB 050525
  54. GRB 050525: TAROT observations of the early afterglow
  55. INTEGRAL detection of GRB 050525
  56. GRB 050525, infrared observations
  57. GRB 050525: observatons of the optical afterglow
  58. GRB050525: ROTSE-III Refined Analysis
  59. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  60. XRF050522: Radio Observations
  61. Swift/UVOT observation of XRF 050522
  62. GRB 050509A: Further I-band imaging
  63. GRB050522,optical observation
  64. GRB050520,optical observation
  65. XRF 050522: Continued NIR P200 Monitoring
  66. Recent GRB BVRcIc field photometry
  67. GRB050520: Radio Observations
  68. XRF 050522: Swift XRT observation
  69. XRF050522, BVRcIc field photometry
  70. XRF050522: Optical Observations
  71. XRF050522: Near-infrared Observations
  72. GRB 050520: VLT/ULTRACAM observations
  73. Swift UVOT Observations of GRB 050520
  74. GRB 050520: Swift XRT refined analysis
  75. XRF 050509c: Swift XRT Upper Limit
  76. XRF050509c: Radio Observations
  77. RBO Observations of GRB050520
  78. GRB 050520: P200 Observations
  79. GRB050520: Liverpool Telescope follow-up
  80. GRB 050520: TAROT optical limit
  81. GRB 050520: VLT/ULTRACAM observations
  82. GRB 050520: OSN optical observations
  83. No Swift-BAT Lightcurves in real-time for next 3 weeks
  84. XRF 050509C: REM NIR and Optical refined analysis
  85. GRB 050504: Swift XRT afterglow candidate has faded
  86. GRB 050509B and short GRB-SN association? (corrected)
  87. GRB 050509B and short GRB-SN association?
  88. GRB050502b: Early Observation
  89. GRB050509b, Bok telescope B-band imaging
  90. GRB050509b, SDSS pre-burst observations
  91. GRB 050509b: Keck/Chandra Cross-Correlation
  92. GRB 050509b: Keck/Chandra Cross-Correlation
  93. Chandra observation of GRB 050509b
  94. GRB 050509b: Swift/UVOT follow-up measurements
  95. GRB050509B: Optical observations at the Very Large Telescope
  96. GRB 050509b: No Optical Variability in XRT Error Circle
  97. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  98. GRB 050509c: ROTSE-III Optical Limits
  99. GRB 050509B: WSRT Radio Observations
  100. GRB 050505, early TAROT observation

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