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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"

36072 results found.

  1. GRB 050709: Swift UVOT and XRT observations
  2. GRB 050712: Swift-BAT Refined Analysis
  3. GRB 050712: Swift XRT afterglow position
  4. GRB 050712: Swift detection of a weak burst
  5. GRB 050709: LCO40 Observations
  6. GRB050709: A Possible Short-Hard GRB Localized by HETE
  7. PROMPT Rc Observations of GRB 050709
  8. GRB 050525a: PROMPT VRcIc Detections
  9. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  10. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  11. GRB 050626 optical observations
  12. GRB 050626: Swift XRT observations
  13. GRB 050701
  14. GRB 050701, optical observations
  15. GRB 050408: ARC 3.5-meter NIR Observations
  16. GRB 050701: Refined XRT analysis
  17. Swift UVOT observations of GRB 050701
  18. GRB 050701: Swift XRT afterglow position
  19. Swift trigger 143708 is really GRB 050701
  20. GRB 050607, radio observations
  21. GRB 050626 - Correction to GCN 3552
  22. GRB 050626 - a long GRB detected with INTEGRAL
  23. GRB 050525A: Swift Late-Time Decay Rate
  24. H3804: A Possible New XRB Detected by HETE
  25. XRF 050509c: Optical monitoring
  26. IBAS Alert #2512 is NOT a GRB
  27. GRB 050416(a): Host Galaxy Redshift Determination
  28. GRB 050607: MDM Observation
  29. GRB 050607 optical decay
  30. GRB 050607: RTT150 optical observations
  31. GRB 050607 : Lulin R-band observation
  32. GRB 050607: PROMPT VRcIc Observations
  33. GRB 050607: RAPTOR-S Early Optical Limits
  34. GRB 050525a, Mid-Infrared Observations
  35. GRB 050607: Optical decay and spectral slope
  36. GRB 050607: MDM Observations
  37. GRB050607,optical observation
  38. GRB 050607 - XRT refined data analysis
  39. Optical Afterglow of GRB 050607
  40. GRB050607 optical limit by "Pi of the Sky"
  41. GRB050607: Swift Detection of a long GRB
  42. GRB050607: P60 Observations
  43. GRB 050603: prediction of t_break
  44. Limits on a SN in the field of GRB 050509b
  45. GRB 050603: Redshift
  46. GRB 050603 - XRT data analysis of the first day
  47. Konus-Wind observation of GRB 050603
  48. GRB 050603: Analysis of UVOT data
  49. GRB 050603: Swift XRT Position
  50. GRB050603: Radio Detection
  51. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  52. GRB 050603: Afterglow Identification from LCO
  53. GRB 050603: INTEGRAL shows it is not a short GRB
  54. GRB 050408: jet break in the XRT light curve
  55. GRB 050525a, infrared observations
  56. GRB 050525a, SMARTS optical/IR afterglow observations
  57. Correction to GCN Circ 3502 on GRB 050528
  58. GRB050528: updated Liverpool Telescope limits
  59. Swift-BAT GRB 050528: a soft burst
  60. Update on Swift-BAT GRB 050528 (Trigger 130679)
  61. GRB050528: BOOTES optical candidate (retraction)
  62. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  63. GRB050528: BOOTES optical candidate
  64. Possible GRB050528: no candidate from Liverpool Telescope
  65. Swift-BAT detection of possible GRB 050528
  66. GRB050525a: Radio Observations
  67. GRB 050509b: refined XRT/Chandra afterglow position analysis
  68. GRB 050525: RTT150, Optical observations
  69. GRB050525a: optical upper limits
  70. GRB 050525a: SARA Observations
  71. GRB 050525B: Swift-BAT observations
  72. GRB 050525: MITSuME Optical Observation in VRI
  73. GRB 050525a: MDM Observations
  74. GRB050525A,optical observation
  75. GRB 050525 : Lulin optical afterglow observations
  76. GRB050525: Super-LOTIS observations
  77. GRB 050525, spectral lag pseudo-redshift
  78. GRB 050525a: Gemini/GMOS Spectra
  79. GRB050306: optical afterglow not confirmed
  80. GRB 050525: BART optical observation
  81. GRB 050525A: BOOTES simultaneous optical observations
  82. GRB 050525A: Swift-BAT refined analysis
  83. GRB050525: Optical observations
  84. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  85. GRB 050525: pseudo-redshift
  86. Swift/UVOT UV and optical detections of GRB 050525
  87. Konus-Wind observation of GRB 050525
  88. GRB 050525: TAROT observations of the early afterglow
  89. INTEGRAL detection of GRB 050525
  90. GRB 050525, infrared observations
  91. GRB 050525: Optical observation
  92. GRB 050525: observatons of the optical afterglow
  93. GRB050525: ROTSE-III Refined Analysis
  94. GRB 050525 - Very Bright, Not Short
  95. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  96. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  97. XRF050522: NIR observations of XRT candidate
  98. XRF050522: Radio Observations
  99. GRB 050509A: Further I-band imaging
  100. GRB050522,optical observation

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