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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"

43626 results found.

  1. GRB 050713A: Swift/UVOT observation
  2. GRB 050713A : Swift-BAT Refined Analysis
  3. GRB050712: Swift UVOT Observation of Afterglow Emission
  4. GRB 050713A XMM-Newton observation
  5. GRB 050713b : Lulin R-band observations
  6. GRB050713B: Faulkes North Telescope observation
  7. RBO RI observations of GRB 050713A
  8. GRB 050713B
  9. GRB050709 : Chandra source optical counterpart
  10. GRB050713: Liverpool Telescope prompt observations
  11. GRB 050712, optical observations
  12. GRB050709: Candidate X-ray Afterglow from Chandra
  13. GRB 050713, R-band observations at NOT
  14. GRB050713: possible I-band afterglow
  15. GRB 050713: Swift detection of Bright Burst
  16. GRB 050713A: ROTSE-III Optical Limits
  17. GRB050712: XRT refined analysis
  18. GRB050709: Radio Observations
  19. GRB 050709: Swift UVOT and XRT observations
  20. GRB 050712: Swift-BAT Refined Analysis
  21. GRB050712: UVOT candidate optical counterpart
  22. GRB 050712: Swift XRT afterglow position
  23. GRB 050712: Swift detection of a weak burst
  24. GRB 050709: LCO40 Observations
  25. GRB050709, optical observations
  26. GRB050709: A Possible Short-Hard GRB Localized by HETE
  27. PROMPT Rc Observations of GRB 050709
  28. GRB 050525a: PROMPT VRcIc Detections
  29. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  30. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  31. GRB 050626 optical observations
  32. GRB 050626: Swift XRT observations
  33. GRB 050701, optical observations
  34. GRB 050408: ARC 3.5-meter NIR Observations
  35. GRB 050701: Refined XRT analysis
  36. Swift UVOT observations of GRB 050701
  37. GRB050701: Swift-BAT Refined analysis
  38. GRB 050701: Swift XRT afterglow position
  39. Swift trigger 143708 is really GRB 050701
  40. GRB 050607, radio observations
  41. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  42. GRB 050626 - a long GRB detected with INTEGRAL
  43. GRB 050525A: Swift Late-Time Decay Rate
  44. GRB050525a: HST Observations
  45. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  46. H3804: A Possible New XRB Detected by HETE
  47. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  48. XRF 050509c: Optical monitoring
  49. Konus-Wind observation of an intermediate burst from SGR 1806-20
  50. IBAS Alert #2512 is NOT a GRB
  51. XRF050509c: Radio Detection
  52. GRB 050416(a): Host Galaxy Redshift Determination
  53. GRB 050607: MDM Observation
  54. GRB 050607 optical decay
  55. GRB 050607: RTT150 optical observations
  56. GRB050607: refined analysis of prompt REM observations
  57. Swift/UVOT observations of GRB050607
  58. GRB 050607: PROMPT VRcIc Observations
  59. GRB050607: KAIT optical limits
  60. GRB 050525a, Mid-Infrared Observations
  61. GRB 050607: Optical decay and spectral slope
  62. GRB 050607 - XRT refined data analysis
  63. Optical Afterglow of GRB 050607
  64. GRB050607: Swift Detection of a long GRB
  65. GRB050607: P60 Observations
  66. GRB050607: prompt REM observations
  67. GRB 050603: prediction of t_break
  68. Limits on a SN in the field of GRB 050509b
  69. GRB 050603: Redshift
  70. GRB 050603 - XRT data analysis of the first day
  71. Konus-Wind observation of GRB 050603
  72. GRB 050603: Analysis of UVOT data
  73. GRB050603: Fading Afterglow observed by Swift UVOT
  74. GRB050603, submillimetre observations
  75. GRB 050603: Swift XRT Position
  76. GRB050603: Radio Detection
  77. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  78. GRB 050603: Afterglow Identification from LCO
  79. GRB 050603: INTEGRAL shows it is not a short GRB
  80. Swift/BAT Detection of GRB050603
  81. GRB 050408: jet break in the XRT light curve
  82. GRB 050525a, infrared observations
  83. GRB 050525a, SMARTS optical/IR afterglow observations
  84. GRB050528, XRT observations
  85. GRB050528: updated Liverpool Telescope limits
  86. Swift-BAT GRB 050528: a soft burst
  87. Update on Swift-BAT GRB 050528 (Trigger 130679)
  88. GRB050528: BOOTES optical candidate (retraction)
  89. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  90. GRB050528: BOOTES optical candidate
  91. Possible GRB050528: no candidate from Liverpool Telescope
  92. Swift-BAT detection of possible GRB 050528
  93. GRB050525a: Radio Observations
  94. GRB 050509b: refined XRT/Chandra afterglow position analysis
  95. GRB 050525: RTT150, Optical observations
  96. GRB050525a: optical upper limits
  97. GRB 050525a: SARA Observations
  98. GRB 050525B: Swift-BAT observations
  99. GRB 050525: MITSuME Optical Observation in VRI
  100. GRB 050525a: MDM Observations

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