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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"

11756 results found.

  1. GRB 050922C: optical obserations
  2. GRB 050922C: ROTSE-IIId Refined Analysis
  3. GRB 050922B: ROTSE-III Optical Limits
  4. Possible GRB 050922 detected by INTEGRAL
  5. GRB050820B: analysis of the XMM-Newton observation
  6. GRB050916: Swift/UVOT Upper Limits
  7. GRB 050918 - A long GRB detected by INTEGRAL
  8. Swift-BAT trigger 155535 is definitely not a GRB
  9. GRB 050916: XRT position
  10. GRB050916: Swift-BAT detection of a long weak burst
  11. GRB 050915B: XRT position
  12. GRB050915B: Swift-BAT detection of a long bright burst
  13. GRB 050915: Swift-BAT refined analysis
  14. GRB050915: P60 Optical Observations
  15. GRB 050915: ROTSE-III optical limits
  16. Swift is in normal operation
  17. GRB 050911: Swift-BAT refined analysis
  18. GRB 050911: z~0.16 cluster in the field
  19. GRB050911: Swift-BAT detection of a long burst
  20. GRB 050910a: TAROT early optical limits
  21. GRB 050906: Possible X-ray Counterpart
  22. GRB 050908: Swift-BAT refined analysis
  23. GRB 050908: Optical observations
  24. GRB 050908: Prompt PROMPT Observations
  25. Swift trigger 154073 is not a GRB
  26. GRB050904: CrAO optical observations
  27. GRB 050906: Radio Observations
  28. GRB 050906: Bright galaxy in BAT error box
  29. GRB 050904: Swift/UVOT observations
  30. GRB 050904: early Swift XRT analysis results
  31. GRB 050827: P200 NIR Observations
  32. GRB050824, HETE-2 Observation
  33. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  34. GRB050824, I-band imaging
  35. GRB 050822: refined XRT analysis
  36. GRB 050824: XRT refined analysis and possible afterglow detection
  37. GRB 050824: ROTSE-III Optical Limits
  38. GRB050820A: RTT150 optical observations
  39. GRB 050822: Swift-BAT refined analysis
  40. GRB050820A: RTT150 optical observations
  41. GRB 050820a - corrections to GCN 3846
  42. GRB 050822: ROTSE-III Prompt Optical Limits
  43. GRB050820B: BAT-Swift detection of a bright GRB
  44. GRB 050820: High Resolution Spectroscopy from Keck
  45. GRB 050820: Swift detection of a GRB
  46. Swift-BAT trigger 150993 is not a GRB
  47. GRB 050815: ROTSE-III Optical Limits
  48. GRB050814: Fading red source
  49. GRB050814: P60 Optical Afterglow Candidate
  50. GRB 050814: XRT refined analysis
  51. GRB050814: Refined analysis of the Swift-BAT burst
  52. GRB 050814: Swift XRT Afterglow Localization
  53. GRB050813: RTT150 optical observations
  54. GRB 050813: KAIT optical limit
  55. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  56. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  57. Detection of an intermediate burst from SGR 1806-20 on August 8
  58. GRB 050807: ROTSE-III Optical Limits
  59. GRB050803, optical observations
  60. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  61. GRB 050803: RTT150 optical observations
  62. GRB050803: CrAO optical observations, possible OT candidate
  63. GRB 050803: Swift-BAT refined analysis
  64. GRB050803: MASTER further analys
  65. GRB 050803: early Swift XRT analysis results
  66. GCN GRB observation 050713A
  67. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  68. GRB050802: CrAO optical observations
  69. GRB 050802: Swift Gamma-ray Burst
  70. GRB 050801: Swift-BAT refined analysis
  71. GRB 050730, corrected photometry and break?
  72. GRB050730: Refined BAT analysis of the Swift-BAT burst
  73. GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
  74. GRB050730: Liverpool Telescope optical observations
  75. GRB 050730, optical candidate
  76. GRB050730: Swift-BAT detection of a weak burst
  77. GRB050713b: Maidanak optical observations
  78. GRB 050724: Chandra Observations of the X-ray Afterglow
  79. GRB 050724, SMARTS optical/IR afterglow observations
  80. GRB 050726, SMARTS optical/IR observations
  81. GRB 050724: J-band observations
  82. GRB 050724: SWIFT XRT refined position
  83. GRB050721A: Swift-BAT detection of a weak burst
  84. GRB 050712, Tautenburg optical afterglow observations
  85. Konus-Wind observation of GRB 050717
  86. Swift detection of GRB 050717
  87. Konus-Wind observation of GRB 050713A
  88. GRB 050714, R-band candidate
  89. GRB 050714A: ROTSE-III Optical Limits
  90. GRB 050714 - A long GRB detected with INTEGRAL
  91. GRB 050712, optical observations
  92. GRB050709: Candidate X-ray Afterglow from Chandra
  93. GRB 050713: Swift detection of Bright Burst
  94. GRB 050713A: ROTSE-III Optical Limits
  95. GRB050709: Radio Observations
  96. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  97. GRB 050626 optical observations
  98. GRB 050626: Swift XRT observations
  99. GRB 050408: ARC 3.5-meter NIR Observations
  100. GRB050701: Swift-BAT Refined analysis

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