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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"

21798 results found.

  1. GRB 050714B: refined XRT analysis
  2. GRB 050713b: RTT150 optical observations
  3. GRB 050714B: optical afterglow
  4. GRB 050714, R-band candidate
  5. GRB 050714, optical observations
  6. GRB 050714A: ROTSE-III Optical Limits
  7. GRB 050713A: RAPTOR detection of early optical emission
  8. GRB050713B :Swift/UVOT observations
  9. GRB050712: TNG R-band observations
  10. GRB 050713A: Swift/UVOT observation
  11. GRB050712: Swift UVOT Observation of Afterglow Emission
  12. GRB 050713A : Lulin R-band observation
  13. GRB 050713A XMM-Newton observation
  14. GRB050713B: Faulkes North Telescope observation
  15. RBO RI observations of GRB 050713A
  16. GRB050709 : Chandra source optical counterpart
  17. GRB 050712, optical observations
  18. GRB050709: Candidate X-ray Afterglow from Chandra
  19. GRB050713: possible I-band afterglow
  20. GRB 050713A: ROTSE-III Optical Limits
  21. GRB050709: Radio Observations
  22. GRB 050709: Swift UVOT and XRT observations
  23. GRB050712: UVOT candidate optical counterpart
  24. GRB 050712: Swift detection of a weak burst
  25. GRB 050709: LCO40 Observations
  26. PROMPT Rc Observations of GRB 050709
  27. GRB 050525a: PROMPT VRcIc Detections
  28. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  29. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  30. GRB 050408: ARC 3.5-meter NIR Observations
  31. Swift UVOT observations of GRB 050701
  32. GRB 050607, radio observations
  33. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  34. GRB050525a: HST Observations
  35. XRF 050509c: Optical monitoring
  36. XRF050509c: Radio Detection
  37. GRB 050607 optical decay
  38. GRB050607: refined analysis of prompt REM observations
  39. GRB 050607: PROMPT VRcIc Observations
  40. GRB 050607: Optical decay and spectral slope
  41. GRB050607,optical observation
  42. GRB 050607 - XRT refined data analysis
  43. Optical Afterglow of GRB 050607
  44. GRB050607: Swift Detection of a long GRB
  45. GRB050607: prompt REM observations
  46. Limits on a SN in the field of GRB 050509b
  47. GRB 050603: Redshift
  48. GRB 050603 - XRT data analysis of the first day
  49. Konus-Wind observation of GRB 050603
  50. GRB050603, submillimetre observations
  51. GRB050603: Radio Detection
  52. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  53. GRB 050603: INTEGRAL shows it is not a short GRB
  54. GRB 050525a, infrared observations
  55. GRB050528: updated Liverpool Telescope limits
  56. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  57. Possible GRB050528: no candidate from Liverpool Telescope
  58. GRB050525a: Radio Observations
  59. GRB 050509b: refined XRT/Chandra afterglow position analysis
  60. GRB 050525: RTT150, Optical observations
  61. GRB 050525a: SARA Observations
  62. GRB 050525B: Swift-BAT observations
  63. GRB 050525: MITSuME Optical Observation in VRI
  64. GRB050525A,optical observation
  65. GRB050525: Super-LOTIS observations
  66. GRB050306: optical afterglow not confirmed
  67. GRB 050525: BART optical observation
  68. GRB 050525A: BOOTES simultaneous optical observations
  69. GRB 050525A: Swift-BAT refined analysis
  70. GRB050525: Optical observations
  71. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  72. Konus-Wind observation of GRB 050525
  73. GRB 050525: TAROT observations of the early afterglow
  74. INTEGRAL detection of GRB 050525
  75. GRB 050525, infrared observations
  76. GRB 050525: observatons of the optical afterglow
  77. GRB050525: ROTSE-III Refined Analysis
  78. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  79. XRF 050522: Swift XRT refined analysis
  80. XRF050522: Radio Observations
  81. Swift/UVOT observation of XRF 050522
  82. GRB 050509A: Further I-band imaging
  83. GRB050522,optical observation
  84. GRB050520,optical observation
  85. XRF 050522: Continued NIR P200 Monitoring
  86. Recent GRB BVRcIc field photometry
  87. GRB050520: Radio Observations
  88. XRF 050522: Swift XRT observation
  89. XRF050522, BVRcIc field photometry
  90. XRF050522: Optical Observations
  91. XRF050522: Near-infrared Observations
  92. GRB 050520: VLT/ULTRACAM observations
  93. Swift UVOT Observations of GRB 050520
  94. GRB 050520: Swift XRT refined analysis
  95. XRF050509c: Radio Observations
  96. RBO Observations of GRB050520
  97. GRB 050520: P200 Observations
  98. GRB 050520: TAROT optical limit
  99. GRB 050520: Swift XRT position
  100. GRB 050520: VLT/ULTRACAM observations

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