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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"

21458 results found.

  1. Swift-BAT Trigger 145729 is not a GRB
  2. GRB 050713A: Swift/UVOT observation
  3. GRB 050713A : Swift-BAT Refined Analysis
  4. GRB050712: Swift UVOT Observation of Afterglow Emission
  5. GRB 050713A XMM-Newton observation
  6. GRB050713B: Faulkes North Telescope observation
  7. RBO RI observations of GRB 050713A
  8. GRB 050713B
  9. GRB050713: Liverpool Telescope prompt observations
  10. GRB050709: Candidate X-ray Afterglow from Chandra
  11. GRB 050713, R-band observations at NOT
  12. GRB050713: possible I-band afterglow
  13. GRB 050713: Swift detection of Bright Burst
  14. GRB 050713A: ROTSE-III Optical Limits
  15. GRB050712: XRT refined analysis
  16. GRB 050709: Swift UVOT and XRT observations
  17. GRB 050712: Swift-BAT Refined Analysis
  18. GRB050712: UVOT candidate optical counterpart
  19. GRB 050712: Swift XRT afterglow position
  20. GRB 050712: Swift detection of a weak burst
  21. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  22. GRB 050626: Swift XRT observations
  23. GRB 050701
  24. GRB 050701, optical observations
  25. GRB 050701: Refined XRT analysis
  26. Swift UVOT observations of GRB 050701
  27. GRB050701: Swift-BAT Refined analysis
  28. GRB 050701: Swift XRT afterglow position
  29. Swift trigger 143708 is really GRB 050701
  30. GRB 050525A: Swift Late-Time Decay Rate
  31. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  32. GRB 050416(a): Host Galaxy Redshift Determination
  33. Swift/UVOT observations of GRB050607
  34. GRB 050607: PROMPT VRcIc Observations
  35. GRB 050607: RAPTOR-S Early Optical Limits
  36. GRB050607: KAIT optical limits
  37. GRB 050607: MDM Observations
  38. GRB050607,optical observation
  39. GRB 050607 - XRT refined data analysis
  40. Optical Afterglow of GRB 050607
  41. GRB050607 optical limit by "Pi of the Sky"
  42. GRB050607: Swift Detection of a long GRB
  43. Limits on a SN in the field of GRB 050509b
  44. GRB 050603: Redshift
  45. GRB 050603 - XRT data analysis of the first day
  46. Konus-Wind observation of GRB 050603
  47. GRB 050603: Analysis of UVOT data
  48. GRB050603: Fading Afterglow observed by Swift UVOT
  49. GRB 050603: Swift XRT Position
  50. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  51. Swift/BAT Detection of GRB050603
  52. GRB 050408: jet break in the XRT light curve
  53. GRB050528, XRT observations
  54. Correction to GCN Circ 3502 on GRB 050528
  55. Swift-BAT GRB 050528: a soft burst
  56. Update on Swift-BAT GRB 050528 (Trigger 130679)
  57. Possible GRB050528: no candidate from Liverpool Telescope
  58. Swift-BAT detection of possible GRB 050528
  59. GRB 050509b: refined XRT/Chandra afterglow position analysis
  60. GRB050525a: optical upper limits
  61. GRB 050525B: Swift-BAT observations
  62. GRB050525A,optical observation
  63. GRB050525: Super-LOTIS observations
  64. GRB 050525, spectral lag pseudo-redshift
  65. GRB050306: optical afterglow not confirmed
  66. GRB 050525A: BOOTES simultaneous optical observations
  67. GRB 050525A: Swift-BAT refined analysis
  68. Swift/UVOT UV and optical detections of GRB 050525
  69. Konus-Wind observation of GRB 050525
  70. GRB 050525: TAROT observations of the early afterglow
  71. INTEGRAL detection of GRB 050525
  72. GRB 050525: Optical observation
  73. GRB050525: ROTSE-III Refined Analysis
  74. GRB 050525 - Very Bright, Not Short
  75. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  76. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  77. XRF050522: NIR observations of XRT candidate
  78. XRF 050522: Swift XRT refined analysis
  79. Swift/UVOT observation of XRF 050522
  80. GRB 050509A: Further I-band imaging
  81. RBO Observations of GRB050522
  82. GRB050509b: optical observations
  83. GRB050520: Radio Observations
  84. XRF 050522: Swift XRT observation
  85. GRB 050520: VLT/ULTRACAM observations
  86. Swift UVOT Observations of GRB 050520
  87. GRB 050520: Swift XRT refined analysis
  88. XRF050509C: Chandra Afterglow Detection
  89. XRF 050509c: Swift XRT Upper Limit
  90. RBO Observations of GRB050520
  91. GRB 050520: P200 Observations
  92. GRB050520: Liverpool Telescope follow-up
  93. GRB 050520: TAROT optical limit
  94. GRB 050520: Swift XRT position
  95. No Swift-BAT Lightcurves in real-time for next 3 weeks
  96. Swift-BAT trigger 122203 is not a real GRB
  97. GRB 050504: Swift XRT afterglow candidate has faded
  98. GRB 050509B and short GRB-SN association? (corrected)
  99. GRB 050509B and short GRB-SN association?
  100. GRB 050509B: Subaru Optical Observations

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