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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"
  1. GRB 050713B
  2. GRB050709 : Chandra source optical counterpart
  3. GRB050713: Liverpool Telescope prompt observations
  4. GRB 050712, optical observations
  5. GRB 050713 : Planned XMM-Newton observation
  6. GRB050709: Candidate X-ray Afterglow from Chandra
  7. GRB 050713, R-band observations at NOT
  8. GRB 050713: ARC NIR Detections and Identification of Fading
  9. GRB050713: possible I-band afterglow
  10. GRB 050713: Swift detection of Bright Burst
  11. GRB 050713A: ROTSE-III Optical Limits
  12. GRB050712: XRT refined analysis
  13. GRB050709: Radio Observations
  14. GRB 050709: Swift UVOT and XRT observations
  15. GRB 050712: Swift-BAT Refined Analysis
  16. GRB050712: UVOT candidate optical counterpart
  17. GRB 050712: Swift XRT afterglow position
  18. GRB 050712: Swift detection of a weak burst
  19. GRB 050709: LCO40 Observations
  20. GRB050709, optical observations
  21. GRB050709: A Possible Short-Hard GRB Localized by HETE
  22. PROMPT Rc Observations of GRB 050709
  23. GRB 050525a: PROMPT VRcIc Detections
  24. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  25. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  26. GRB 050626 optical observations
  27. GRB 050626: Swift XRT observations
  28. GRB 050701
  29. GRB 050701, optical observations
  30. GRB 050408: ARC 3.5-meter NIR Observations
  31. GRB 050701: Refined XRT analysis
  32. Swift UVOT observations of GRB 050701
  33. GRB050701: Swift-BAT Refined analysis
  34. GRB 050701: Swift XRT afterglow position
  35. Swift trigger 143708 is really GRB 050701
  36. GRB 050607, radio observations
  37. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  38. GRB 050626 - Correction to GCN 3552
  39. GRB 050626 - a long GRB detected with INTEGRAL
  40. GRB 050525A: Swift Late-Time Decay Rate
  41. GRB050525a: HST Observations
  42. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  43. H3804: A Possible New XRB Detected by HETE
  44. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  45. XRF 050509c: Optical monitoring
  46. Konus-Wind observation of an intermediate burst from SGR 1806-20
  47. IBAS Alert #2512 is NOT a GRB
  48. XRF050509c: Radio Detection
  49. GRB 050416(a): Host Galaxy Redshift Determination
  50. GRB 050607: MDM Observation
  51. GRB 050607 optical decay
  52. GRB 050607: RTT150 optical observations
  53. GRB050607: refined analysis of prompt REM observations
  54. Swift/UVOT observations of GRB050607
  55. GRB 050607 : Lulin R-band observation
  56. GRB 050607: PROMPT VRcIc Observations
  57. GRB 050607: RAPTOR-S Early Optical Limits
  58. GRB050607: KAIT optical limits
  59. GRB 050525a, Mid-Infrared Observations
  60. GRB 050607: Optical decay and spectral slope
  61. GRB 050607: MDM Observations
  62. GRB050607,optical observation
  63. GRB 050607 - XRT refined data analysis
  64. Optical Afterglow of GRB 050607
  65. GRB050607 optical limit by "Pi of the Sky"
  66. GRB050607: Swift Detection of a long GRB
  67. GRB050607: P60 Observations
  68. GRB050607: prompt REM observations
  69. GRB 050603: prediction of t_break
  70. Limits on a SN in the field of GRB 050509b
  71. GRB 050603: Redshift
  72. GRB 050603 - XRT data analysis of the first day
  73. Konus-Wind observation of GRB 050603
  74. GRB 050603: Analysis of UVOT data
  75. GRB050603: Fading Afterglow observed by Swift UVOT
  76. GRB050603, submillimetre observations
  77. GRB 050603: Swift XRT Position
  78. GRB050603: Radio Detection
  79. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  80. GRB 050603: Afterglow Identification from LCO
  81. GRB 050603: INTEGRAL shows it is not a short GRB
  82. Swift/BAT Detection of GRB050603
  83. GRB 050408: jet break in the XRT light curve
  84. GRB 050525a, infrared observations
  85. GRB 050525a, SMARTS optical/IR afterglow observations
  86. GRB050528, XRT observations
  87. Correction to GCN Circ 3502 on GRB 050528
  88. GRB050528: updated Liverpool Telescope limits
  89. Swift-BAT GRB 050528: a soft burst
  90. Update on Swift-BAT GRB 050528 (Trigger 130679)
  91. GRB050528: BOOTES optical candidate (retraction)
  92. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  93. GRB050528: BOOTES optical candidate
  94. Possible GRB050528: no candidate from Liverpool Telescope
  95. Swift-BAT detection of possible GRB 050528
  96. GRB050525a: Radio Observations
  97. GRB 050509b: refined XRT/Chandra afterglow position analysis
  98. GRB 050525: RTT150, Optical observations
  99. GRB050525a: optical upper limits
  100. GRB 050525a: SARA Observations

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