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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"

28095 results found.

  1. GRB050709: Radio Observations
  2. GRB 050709: Swift UVOT and XRT observations
  3. GRB 050712: Swift-BAT Refined Analysis
  4. GRB050712: UVOT candidate optical counterpart
  5. GRB 050709: LCO40 Observations
  6. GRB050709, optical observations
  7. PROMPT Rc Observations of GRB 050709
  8. GRB 050525a: PROMPT VRcIc Detections
  9. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  10. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  11. GRB 050626: Swift XRT observations
  12. GRB 050408: ARC 3.5-meter NIR Observations
  13. GRB 050701: Refined XRT analysis
  14. Swift UVOT observations of GRB 050701
  15. GRB050701: Swift-BAT Refined analysis
  16. Swift trigger 143708 is really GRB 050701
  17. GRB 050607, radio observations
  18. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  19. GRB050525a: HST Observations
  20. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  21. XRF 050509c: Optical monitoring
  22. Konus-Wind observation of an intermediate burst from SGR 1806-20
  23. XRF050509c: Radio Detection
  24. GRB 050607 optical decay
  25. GRB050607: refined analysis of prompt REM observations
  26. GRB 050607: PROMPT VRcIc Observations
  27. GRB 050607: Optical decay and spectral slope
  28. GRB050607,optical observation
  29. Optical Afterglow of GRB 050607
  30. GRB050607: Swift Detection of a long GRB
  31. GRB050607: prompt REM observations
  32. Limits on a SN in the field of GRB 050509b
  33. GRB 050603 - XRT data analysis of the first day
  34. GRB050603, submillimetre observations
  35. GRB050603: Radio Detection
  36. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  37. GRB 050603: INTEGRAL shows it is not a short GRB
  38. GRB 050525a, infrared observations
  39. GRB050528, XRT observations
  40. GRB050528: updated Liverpool Telescope limits
  41. Swift-BAT GRB 050528: a soft burst
  42. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  43. Possible GRB050528: no candidate from Liverpool Telescope
  44. GRB050525a: Radio Observations
  45. GRB 050509b: refined XRT/Chandra afterglow position analysis
  46. GRB 050525: RTT150, Optical observations
  47. GRB 050525a: SARA Observations
  48. GRB 050525B: Swift-BAT observations
  49. GRB 050525: MITSuME Optical Observation in VRI
  50. GRB050525A,optical observation
  51. GRB050525: Super-LOTIS observations
  52. GRB 050525, spectral lag pseudo-redshift
  53. GRB050306: optical afterglow not confirmed
  54. GRB 050525: BART optical observation
  55. GRB 050525A: BOOTES simultaneous optical observations
  56. GRB 050525A: Swift-BAT refined analysis
  57. GRB050525: Optical observations
  58. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  59. Konus-Wind observation of GRB 050525
  60. GRB 050525: TAROT observations of the early afterglow
  61. INTEGRAL detection of GRB 050525
  62. GRB 050525, infrared observations
  63. GRB 050525: observatons of the optical afterglow
  64. GRB050525: ROTSE-III Refined Analysis
  65. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  66. XRF050522: Radio Observations
  67. Swift/UVOT observation of XRF 050522
  68. GRB 050509A: Further I-band imaging
  69. GRB050522,optical observation
  70. GRB050520,optical observation
  71. XRF 050522: Continued NIR P200 Monitoring
  72. RBO Observations of GRB050522
  73. Recent GRB BVRcIc field photometry
  74. GRB050520: Radio Observations
  75. XRF 050522: Swift XRT observation
  76. XRF050522, BVRcIc field photometry
  77. XRF050522: Optical Observations
  78. XRF050522: Near-infrared Observations
  79. GRB 050520: VLT/ULTRACAM observations
  80. GRB 050520: Swift XRT refined analysis
  81. XRF050509C: Chandra Afterglow Detection
  82. XRF050509c: Radio Observations
  83. GRB 050520: P200 Observations
  84. GRB 050520: TAROT optical limit
  85. GRB 050520: VLT/ULTRACAM observations
  86. XRF 050509c optical afterglow
  87. GRB 050509B and short GRB-SN association? (corrected)
  88. GRB 050509B and short GRB-SN association?
  89. GRB050502b: Early Observation
  90. GRB050509b, Bok telescope B-band imaging
  91. Refined Chandra analysis of GRB 050509b
  92. GRB050509b, SDSS pre-burst observations
  93. GRB 050509b: Keck/Chandra Cross-Correlation
  94. GRB 050509b: Keck/Chandra Cross-Correlation
  95. Chandra observation of GRB 050509b
  96. GRB 050509b: RAPTOR deep, early limits.
  97. GRB050509B: Optical observations at the Very Large Telescope
  98. GRB 050509b: No Optical Variability in XRT Error Circle
  99. GRB 050509a: Swift-BAT refined analysis
  100. GRB 050509c: ROTSE-III Optical Limits

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