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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"

27392 results found.

  1. GRB 050408: Mercator Optical Observations
  2. GRB 050408: Optical afterglow confirmed
  3. GRB 050408: opitcal observation
  4. GRB 050408, optical observations
  5. GRB 050408 optical candidate
  6. GRB 050408: Swift XRT Position
  7. GRB050408: MASTER optical observations
  8. GRB050401: Radio Detection
  9. GRB 050406: early Swift XRT analysis results
  10. GRB 050406 BAT refined analysis
  11. GRB 050406: Early observations with Swift-UVOT
  12. Swift-BAT detection of GRB 050406
  13. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  14. GRB 050401: VLT spectroscopic redshift
  15. GRB 050401 BAT refined analysis
  16. GRB050401: TNG R-band observation
  17. GRB 050402: Early observations with Swift-UVOT
  18. Swift Trigger 113225: P60 Observations
  19. GRB 050401: Optical afterglow confirmed
  20. GRB 050401: Prompt XRT position
  21. Retraction of three Swift GRB triggers
  22. GRB050331: No Afterglow Detected
  23. Swift-BAT detection of GRB 050331b
  24. GRB 050331: Swift UVOT Source
  25. Swift-BAT detection of GRB 050331
  26. GRB 050326: Early observations with Swift-UVOT
  27. GRB 050326 XMM-Newton observation
  28. GRB 050326: Swift XRT Position
  29. GRB 050326 BAT refined analysis
  30. GRB050326: delayed XRT observation
  31. GRB050319, color indices
  32. GRB050319: optical observation, March 20-22
  33. GRB050319: RTT150 Optical Observations
  34. Swift-BAT trigger 112060 is not a real GRB
  35. GRB 050318: Swift-BAT refined analysis
  36. GRB050319: VLA Observations
  37. GRB050319: radio observation
  38. GRB 050319: Swift-UVOT detection of the afterglow
  39. GRB 050315: Variability Analysis of Swift BAT Time History
  40. GRB050319: Radio Observations
  41. GRB 050319: NIR afterglow candidate
  42. GRB 050319:Near IR afterglow
  43. GRB 050318: SWIFT-UVOT refined analysis
  44. GRB 050319 : Confirmation of optical afterglow decay
  45. GRB 050319: Swift-BAT refined analysis
  46. GRB050319,optical observation
  47. GRB 050318: Swift/UVOT detection of afterglow emission
  48. RXTE Observations of GRB050318
  49. GRB050223: analysis of the XMM-Newton observation
  50. GRB050316: MASTER before, simultanious and follow up optical
  51. GRB 050306: ROTSE-III early limits
  52. GRB050316: MASTER optical observations
  53. GRB 050315: Swift-BAT further refined analysis
  54. GRB 050315 I-band observations
  55. GRB050315: Radio afterglow
  56. GRB050315: Swift-BAT Refined analysis
  57. Non-detection of GRB050315 in ATCA Radio Observations
  58. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  59. GRB 050315: Early Observations with Swift/UVOT
  60. GRB 050306: Radio Observations
  61. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  62. GRB 050306: optical afterglow
  63. Swift-BAT trigger 107873: No Swift XRT counterpart
  64. GRB 050306: Confirmation of X-ray afterglow
  65. GRB 050306: further TAROT optical data
  66. GRB050309: Early optical limit from P60
  67. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  68. GRB 050309 : Lulin R-band observation
  69. Swift 107873: P60 Optical Observations
  70. GRB 050306: R-band observations
  71. GRB 050306: REM optical-infrared observations
  72. GRB 050306: Possible X-ray Afterglow Position from the Swift
  73. GRB 050306: TAROT optical observations
  74. GRB 050306,optical observation
  75. Ongoing activity of SGR 1806-20 after the giant flare
  76. GRB050215B: Late-Time Swift UVOT Observations
  77. PROMPT VRcIc Observations of GRB 050223
  78. XRF/GRB 050215B: Radio Observations
  79. XMM-Newton Images of GRB 050223
  80. GRB 050219b: candidate NIR afterglow
  81. Confirmed XRF nature for GRB050215b
  82. GRB050223 XMM-Newton observation
  83. INTEGRAL detection of GRB 050223
  84. GRB050223: ROTSE-III Optical Observations
  85. GRB 050223 Swift/BAT detection of a burst
  86. GRB 050223: Swift XRT Position
  87. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  88. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  89. GRB 050219a: Optical observations from LCO
  90. GRB 050219b: Optical and near-IR observations from LCO
  91. GRB 050219b: Swift-BAT detection of a burst
  92. GRB 050219b: CORRECTION: Swift XRT Position
  93. GRB 050219b: Swift XRT Position
  94. GRB 050219: Swift-BAT detection of a burst
  95. GRB 050215b: XRT confirmation of IR afterglow candidate
  96. GRB050215b: P60 Optical Observations
  97. GRB 050215b: Swift XRT Source Variability
  98. GRB 050215B: candidate afterglow
  99. GRB 050215b : Lulin follow-up observation
  100. GRB 050215b, BOOTES-2 simultaneous optical observations

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