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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"

28090 results found.

  1. GRB 050408: opitcal observation
  2. GRB 050408, optical observations
  3. GRB 050408 optical candidate
  4. GRB 050408: Swift XRT Position
  5. GRB050408: MASTER optical observations
  6. GRB050401: Radio Detection
  7. GRB 050406: early Swift XRT analysis results
  8. GRB 050406 BAT refined analysis
  9. GRB 050406: Early observations with Swift-UVOT
  10. Swift-BAT detection of GRB 050406
  11. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  12. GRB 050401: VLT spectroscopic redshift
  13. GRB 050401 BAT refined analysis
  14. GRB050401: TNG R-band observation
  15. GRB 050402: Early observations with Swift-UVOT
  16. Swift Trigger 113225: P60 Observations
  17. GRB 050401: Optical afterglow confirmed
  18. GRB 050401: Prompt XRT position
  19. Retraction of three Swift GRB triggers
  20. GRB050331: No Afterglow Detected
  21. Swift-BAT detection of GRB 050331b
  22. GRB 050331: Swift UVOT Source
  23. Swift-BAT detection of GRB 050331
  24. GRB 050326: Early observations with Swift-UVOT
  25. GRB 050326 XMM-Newton observation
  26. GRB 050326: Swift XRT Position
  27. GRB 050326 BAT refined analysis
  28. GRB050326: delayed XRT observation
  29. GRB050319, color indices
  30. GRB050319: optical observation, March 20-22
  31. GRB050319: RTT150 Optical Observations
  32. Swift-BAT trigger 112060 is not a real GRB
  33. GRB 050318: Swift-BAT refined analysis
  34. GRB050319: VLA Observations
  35. GRB050319: radio observation
  36. GRB 050319: Swift-UVOT detection of the afterglow
  37. GRB 050315: Variability Analysis of Swift BAT Time History
  38. GRB050319: Radio Observations
  39. GRB 050319: NIR afterglow candidate
  40. GRB 050319:Near IR afterglow
  41. GRB 050318: SWIFT-UVOT refined analysis
  42. GRB 050319 : Confirmation of optical afterglow decay
  43. GRB 050319: Swift-BAT refined analysis
  44. GRB050319,optical observation
  45. GRB 050318: Swift/UVOT detection of afterglow emission
  46. RXTE Observations of GRB050318
  47. GRB050223: analysis of the XMM-Newton observation
  48. GRB050316: MASTER before, simultanious and follow up optical
  49. GRB 050306: ROTSE-III early limits
  50. GRB050316: MASTER optical observations
  51. GRB 050315: Swift-BAT further refined analysis
  52. GRB 050315 I-band observations
  53. GRB050315: Radio afterglow
  54. GRB050315: Swift-BAT Refined analysis
  55. Non-detection of GRB050315 in ATCA Radio Observations
  56. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  57. GRB 050315: Early Observations with Swift/UVOT
  58. GRB 050306: Radio Observations
  59. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  60. GRB 050306: optical afterglow
  61. Swift-BAT trigger 107873: No Swift XRT counterpart
  62. GRB 050306: Confirmation of X-ray afterglow
  63. GRB 050306: further TAROT optical data
  64. GRB050309: Early optical limit from P60
  65. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  66. GRB 050309 : Lulin R-band observation
  67. Swift 107873: P60 Optical Observations
  68. GRB 050306: R-band observations
  69. GRB 050306: REM optical-infrared observations
  70. GRB 050306: Possible X-ray Afterglow Position from the Swift
  71. GRB 050306: TAROT optical observations
  72. GRB 050306,optical observation
  73. Ongoing activity of SGR 1806-20 after the giant flare
  74. GRB050215B: Late-Time Swift UVOT Observations
  75. PROMPT VRcIc Observations of GRB 050223
  76. XRF/GRB 050215B: Radio Observations
  77. XMM-Newton Images of GRB 050223
  78. GRB 050219b: candidate NIR afterglow
  79. Confirmed XRF nature for GRB050215b
  80. GRB050223 XMM-Newton observation
  81. INTEGRAL detection of GRB 050223
  82. GRB050223: ROTSE-III Optical Observations
  83. GRB 050223 Swift/BAT detection of a burst
  84. GRB 050223: Swift XRT Position
  85. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  86. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  87. GRB 050219a: Optical observations from LCO
  88. GRB 050219b: Optical and near-IR observations from LCO
  89. GRB 050219b: Swift-BAT detection of a burst
  90. GRB 050219b: CORRECTION: Swift XRT Position
  91. GRB 050219b: Swift XRT Position
  92. GRB 050219: Swift-BAT detection of a burst
  93. GRB 050215b: XRT confirmation of IR afterglow candidate
  94. GRB050215b: P60 Optical Observations
  95. GRB 050215b: Swift XRT Source Variability
  96. GRB 050215B: candidate afterglow
  97. GRB 050215b : Lulin follow-up observation
  98. GRB 050215b, BOOTES-2 simultaneous optical observations
  99. GRB050215A: ROTSE-III Optical Observations
  100. GRB050209: TAROT optical observations

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