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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"

42193 results found.

  1. GRB 050713: Swift detection of Bright Burst
  2. GRB 050713A: ROTSE-III Optical Limits
  3. GRB050712: XRT refined analysis
  4. GRB050709: Radio Observations
  5. GRB 050709: Swift UVOT and XRT observations
  6. GRB 050712: Swift-BAT Refined Analysis
  7. GRB050712: UVOT candidate optical counterpart
  8. GRB 050712: Swift XRT afterglow position
  9. GRB 050712: Swift detection of a weak burst
  10. GRB 050709: LCO40 Observations
  11. GRB050709, optical observations
  12. GRB050709: A Possible Short-Hard GRB Localized by HETE
  13. GRB 050525a: PROMPT VRcIc Detections
  14. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  15. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  16. GRB 050626 optical observations
  17. GRB 050626: Swift XRT observations
  18. GRB 050701, optical observations
  19. Swift UVOT observations of GRB 050701
  20. GRB050701: Swift-BAT Refined analysis
  21. GRB 050701: Swift XRT afterglow position
  22. Swift trigger 143708 is really GRB 050701
  23. GRB 050607, radio observations
  24. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  25. GRB 050626 - a long GRB detected with INTEGRAL
  26. GRB 050525A: Swift Late-Time Decay Rate
  27. GRB050525a: HST Observations
  28. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  29. H3804: A Possible New XRB Detected by HETE
  30. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  31. XRF 050509c: Optical monitoring
  32. Konus-Wind observation of an intermediate burst from SGR 1806-20
  33. XRF050509c: Radio Detection
  34. GRB 050416(a): Host Galaxy Redshift Determination
  35. GRB 050607: MDM Observation
  36. GRB 050607 optical decay
  37. GRB 050607: RTT150 optical observations
  38. GRB050607: refined analysis of prompt REM observations
  39. Swift/UVOT observations of GRB050607
  40. GRB 050607 : Lulin R-band observation
  41. GRB 050607: PROMPT VRcIc Observations
  42. GRB 050607: RAPTOR-S Early Optical Limits
  43. GRB050607: KAIT optical limits
  44. GRB 050525a, Mid-Infrared Observations
  45. GRB 050607: Optical decay and spectral slope
  46. GRB 050607: MDM Observations
  47. GRB050607,optical observation
  48. GRB 050607 - XRT refined data analysis
  49. Optical Afterglow of GRB 050607
  50. GRB050607 optical limit by "Pi of the Sky"
  51. GRB050607: Swift Detection of a long GRB
  52. GRB050607: P60 Observations
  53. GRB050607: prompt REM observations
  54. GRB 050603: prediction of t_break
  55. Limits on a SN in the field of GRB 050509b
  56. GRB 050603: Redshift
  57. GRB 050603 - XRT data analysis of the first day
  58. GRB050603: Fading Afterglow observed by Swift UVOT
  59. GRB050603, submillimetre observations
  60. GRB 050603: Swift XRT Position
  61. GRB050603: Radio Detection
  62. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  63. GRB 050603: Afterglow Identification from LCO
  64. GRB 050603: INTEGRAL shows it is not a short GRB
  65. Swift/BAT Detection of GRB050603
  66. GRB 050408: jet break in the XRT light curve
  67. GRB 050525a, infrared observations
  68. GRB 050525a, SMARTS optical/IR afterglow observations
  69. GRB050528, XRT observations
  70. Swift-BAT GRB 050528: a soft burst
  71. Update on Swift-BAT GRB 050528 (Trigger 130679)
  72. GRB050528: BOOTES optical candidate (retraction)
  73. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  74. GRB050528: BOOTES optical candidate
  75. Swift-BAT detection of possible GRB 050528
  76. GRB050525a: Radio Observations
  77. GRB 050509b: refined XRT/Chandra afterglow position analysis
  78. GRB 050525: RTT150, Optical observations
  79. GRB050525a: optical upper limits
  80. GRB 050525a: SARA Observations
  81. GRB 050525B: Swift-BAT observations
  82. GRB 050525: MITSuME Optical Observation in VRI
  83. GRB 050525a: MDM Observations
  84. GRB050525A,optical observation
  85. GRB 050525 : Lulin optical afterglow observations
  86. GRB050525: Super-LOTIS observations
  87. GRB 050525, spectral lag pseudo-redshift
  88. GRB 050525a: Gemini/GMOS Spectra
  89. GRB050306: optical afterglow not confirmed
  90. GRB 050525: BART optical observation
  91. GRB 050525A: BOOTES simultaneous optical observations
  92. GRB 050525A: Swift-BAT refined analysis
  93. GRB050525: Optical observations
  94. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  95. Swift/UVOT UV and optical detections of GRB 050525
  96. Konus-Wind observation of GRB 050525
  97. GRB 050525: TAROT observations of the early afterglow
  98. INTEGRAL detection of GRB 050525
  99. GRB 050525, infrared observations
  100. GRB 050525: Optical observation

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