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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"

20362 results found.

  1. GRB050709 : Chandra source optical counterpart
  2. GRB050713: Liverpool Telescope prompt observations
  3. GRB 050712, optical observations
  4. GRB050709: Candidate X-ray Afterglow from Chandra
  5. GRB050713: possible I-band afterglow
  6. GRB 050713A: ROTSE-III Optical Limits
  7. GRB050709: Radio Observations
  8. GRB050712: UVOT candidate optical counterpart
  9. GRB 050712: Swift detection of a weak burst
  10. GRB 050709: LCO40 Observations
  11. PROMPT Rc Observations of GRB 050709
  12. GRB 050525a: PROMPT VRcIc Detections
  13. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  14. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  15. GRB 050626 optical observations
  16. GRB 050408: ARC 3.5-meter NIR Observations
  17. Swift UVOT observations of GRB 050701
  18. GRB 050607, radio observations
  19. GRB050525a: HST Observations
  20. XRF 050509c: Optical monitoring
  21. XRF050509c: Radio Detection
  22. GRB 050607 optical decay
  23. GRB050607: refined analysis of prompt REM observations
  24. GRB 050607: PROMPT VRcIc Observations
  25. GRB 050607: Optical decay and spectral slope
  26. GRB050607,optical observation
  27. Optical Afterglow of GRB 050607
  28. GRB050607: Swift Detection of a long GRB
  29. GRB050607: prompt REM observations
  30. Limits on a SN in the field of GRB 050509b
  31. GRB050603, submillimetre observations
  32. GRB050603: Radio Detection
  33. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  34. GRB 050603: Afterglow Identification from LCO
  35. GRB 050603: INTEGRAL shows it is not a short GRB
  36. Swift/BAT Detection of GRB050603
  37. GRB 050525a, infrared observations
  38. GRB050528: updated Liverpool Telescope limits
  39. Swift-BAT GRB 050528: a soft burst
  40. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  41. Possible GRB050528: no candidate from Liverpool Telescope
  42. Swift-BAT detection of possible GRB 050528
  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. GRB 050525 : Lulin optical afterglow observations
  51. GRB050525: Super-LOTIS observations
  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: Optical observation
  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. 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. XRF 050509c: Swift XRT Upper Limit
  81. XRF050509c: Radio Observations
  82. RBO Observations of GRB050520
  83. GRB 050520: P200 Observations
  84. GRB 050520: TAROT optical limit
  85. GRB 050520: VLT/ULTRACAM observations
  86. GRB 050504: Swift XRT afterglow candidate has faded
  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. 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. 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 050505, early TAROT observation
  100. GRB050509c: REM NIR and Optical observations

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