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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"

28094 results found.

  1. GRB 050709: Swift UVOT and XRT observations
  2. GRB 050712: Swift-BAT Refined Analysis
  3. GRB050712: UVOT candidate optical counterpart
  4. GRB 050709: LCO40 Observations
  5. GRB050709, optical observations
  6. PROMPT Rc Observations of GRB 050709
  7. GRB 050525a: PROMPT VRcIc Detections
  8. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  9. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  10. GRB 050626: Swift XRT observations
  11. GRB 050408: ARC 3.5-meter NIR Observations
  12. GRB 050701: Refined XRT analysis
  13. Swift UVOT observations of GRB 050701
  14. GRB050701: Swift-BAT Refined analysis
  15. Swift trigger 143708 is really GRB 050701
  16. GRB 050607, radio observations
  17. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  18. GRB050525a: HST Observations
  19. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  20. XRF 050509c: Optical monitoring
  21. Konus-Wind observation of an intermediate burst from SGR 1806-20
  22. XRF050509c: Radio Detection
  23. GRB 050607 optical decay
  24. GRB050607: refined analysis of prompt REM observations
  25. GRB 050607: PROMPT VRcIc Observations
  26. GRB 050607: Optical decay and spectral slope
  27. GRB050607,optical observation
  28. Optical Afterglow of GRB 050607
  29. GRB050607: Swift Detection of a long GRB
  30. GRB050607: prompt REM observations
  31. Limits on a SN in the field of GRB 050509b
  32. GRB 050603 - XRT data analysis of the first day
  33. GRB050603, submillimetre observations
  34. GRB050603: Radio Detection
  35. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  36. GRB 050603: INTEGRAL shows it is not a short GRB
  37. GRB 050525a, infrared observations
  38. GRB050528, XRT observations
  39. GRB050528: updated Liverpool Telescope limits
  40. Swift-BAT GRB 050528: a soft burst
  41. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  42. Possible GRB050528: no candidate from Liverpool Telescope
  43. GRB050525a: Radio Observations
  44. GRB 050509b: refined XRT/Chandra afterglow position analysis
  45. GRB 050525: RTT150, Optical observations
  46. GRB 050525a: SARA Observations
  47. GRB 050525B: Swift-BAT observations
  48. GRB 050525: MITSuME Optical Observation in VRI
  49. GRB050525A,optical observation
  50. GRB050525: Super-LOTIS observations
  51. GRB 050525, spectral lag pseudo-redshift
  52. GRB050306: optical afterglow not confirmed
  53. GRB 050525: BART optical observation
  54. GRB 050525A: BOOTES simultaneous optical observations
  55. GRB 050525A: Swift-BAT refined analysis
  56. GRB050525: Optical observations
  57. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  58. Konus-Wind observation of GRB 050525
  59. GRB 050525: TAROT observations of the early afterglow
  60. INTEGRAL detection of GRB 050525
  61. GRB 050525, infrared observations
  62. GRB 050525: observatons of the optical afterglow
  63. GRB050525: ROTSE-III Refined Analysis
  64. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  65. XRF050522: Radio Observations
  66. Swift/UVOT observation of XRF 050522
  67. GRB 050509A: Further I-band imaging
  68. GRB050522,optical observation
  69. GRB050520,optical observation
  70. XRF 050522: Continued NIR P200 Monitoring
  71. RBO Observations of GRB050522
  72. Recent GRB BVRcIc field photometry
  73. GRB050520: Radio Observations
  74. XRF 050522: Swift XRT observation
  75. XRF050522, BVRcIc field photometry
  76. XRF050522: Optical Observations
  77. XRF050522: Near-infrared Observations
  78. GRB 050520: VLT/ULTRACAM observations
  79. GRB 050520: Swift XRT refined analysis
  80. XRF050509C: Chandra Afterglow Detection
  81. XRF050509c: Radio Observations
  82. GRB 050520: P200 Observations
  83. GRB 050520: TAROT optical limit
  84. GRB 050520: VLT/ULTRACAM observations
  85. XRF 050509c optical afterglow
  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. Refined Chandra analysis of GRB 050509b
  91. GRB050509b, SDSS pre-burst observations
  92. GRB 050509b: Keck/Chandra Cross-Correlation
  93. GRB 050509b: Keck/Chandra Cross-Correlation
  94. Chandra observation of GRB 050509b
  95. GRB 050509b: RAPTOR deep, early limits.
  96. GRB050509B: Optical observations at the Very Large Telescope
  97. GRB 050509b: No Optical Variability in XRT Error Circle
  98. GRB 050509a: Swift-BAT refined analysis
  99. GRB 050509c: ROTSE-III Optical Limits
  100. GRB 050505, early TAROT observation

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