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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"

24887 results found.

  1. GRB 050408: Swift XRT Position
  2. GRB050408: MASTER optical observations
  3. GRB050401: Radio Detection
  4. GRB 050406: early Swift XRT analysis results
  5. GRB 050406 BAT refined analysis
  6. GRB 050406: Early observations with Swift-UVOT
  7. Swift-BAT detection of GRB 050406
  8. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  9. GRB 050401: VLT spectroscopic redshift
  10. GRB 050401 BAT refined analysis
  11. GRB050401: TNG R-band observation
  12. GRB 050402: Early observations with Swift-UVOT
  13. Swift Trigger 113225: P60 Observations
  14. GRB 050401: Optical afterglow confirmed
  15. GRB 050401: Prompt XRT position
  16. Retraction of three Swift GRB triggers
  17. GRB050331: No Afterglow Detected
  18. Swift-BAT detection of GRB 050331b
  19. GRB 050331: Swift UVOT Source
  20. Swift-BAT detection of GRB 050331
  21. GRB 050326: Early observations with Swift-UVOT
  22. GRB 050326 XMM-Newton observation
  23. GRB 050326: Swift XRT Position
  24. GRB 050326 BAT refined analysis
  25. GRB050326: delayed XRT observation
  26. GRB050319, color indices
  27. GRB050319: optical observation, March 20-22
  28. GRB050319: RTT150 Optical Observations
  29. Swift-BAT trigger 112060 is not a real GRB
  30. GRB 050318: Swift-BAT refined analysis
  31. GRB050319: VLA Observations
  32. GRB050319: radio observation
  33. GRB 050319: Swift-UVOT detection of the afterglow
  34. GRB 050315: Variability Analysis of Swift BAT Time History
  35. GRB050319: Radio Observations
  36. GRB 050319: NIR afterglow candidate
  37. GRB 050319:Near IR afterglow
  38. GRB 050318: SWIFT-UVOT refined analysis
  39. GRB 050319 : Confirmation of optical afterglow decay
  40. GRB 050319: Swift-BAT refined analysis
  41. GRB050319,optical observation
  42. GRB 050318: Swift/UVOT detection of afterglow emission
  43. RXTE Observations of GRB050318
  44. GRB050223: analysis of the XMM-Newton observation
  45. GRB050316: MASTER before, simultanious and follow up optical
  46. GRB 050306: ROTSE-III early limits
  47. GRB050316: MASTER optical observations
  48. GRB 050315: Swift-BAT further refined analysis
  49. GRB 050315 I-band observations
  50. GRB050315: Radio afterglow
  51. GRB050315: Swift-BAT Refined analysis
  52. Non-detection of GRB050315 in ATCA Radio Observations
  53. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  54. GRB 050315: Early Observations with Swift/UVOT
  55. GRB 050306: Radio Observations
  56. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  57. GRB 050306: optical afterglow
  58. Swift-BAT trigger 107873: No Swift XRT counterpart
  59. GRB 050306: Confirmation of X-ray afterglow
  60. GRB 050306: further TAROT optical data
  61. GRB050309: Early optical limit from P60
  62. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  63. GRB 050309 : Lulin R-band observation
  64. Swift 107873: P60 Optical Observations
  65. GRB 050306: R-band observations
  66. GRB 050306: REM optical-infrared observations
  67. GRB 050306: Possible X-ray Afterglow Position from the Swift
  68. GRB 050306: TAROT optical observations
  69. GRB 050306,optical observation
  70. Ongoing activity of SGR 1806-20 after the giant flare
  71. GRB050215B: Late-Time Swift UVOT Observations
  72. PROMPT VRcIc Observations of GRB 050223
  73. XRF/GRB 050215B: Radio Observations
  74. XMM-Newton Images of GRB 050223
  75. GRB 050219b: candidate NIR afterglow
  76. Confirmed XRF nature for GRB050215b
  77. GRB050223 XMM-Newton observation
  78. INTEGRAL detection of GRB 050223
  79. GRB050223: ROTSE-III Optical Observations
  80. GRB 050223 Swift/BAT detection of a burst
  81. GRB 050223: Swift XRT Position
  82. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  83. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  84. GRB 050219a: Optical observations from LCO
  85. GRB 050219b: Optical and near-IR observations from LCO
  86. GRB 050219b: Swift-BAT detection of a burst
  87. GRB 050219b: CORRECTION: Swift XRT Position
  88. GRB 050219b: Swift XRT Position
  89. GRB 050219: Swift-BAT detection of a burst
  90. GRB 050215b: XRT confirmation of IR afterglow candidate
  91. GRB050215b: P60 Optical Observations
  92. GRB 050215b: Swift XRT Source Variability
  93. GRB 050215B: candidate afterglow
  94. GRB 050215b : Lulin follow-up observation
  95. GRB 050215b, BOOTES-2 simultaneous optical observations
  96. GRB050215A: ROTSE-III Optical Observations
  97. GRB050209: TAROT optical observations
  98. GRB 050209(=U11568): Duration and spectrum
  99. GRB050209: REM optical observations
  100. GRB 050209 I-band observation

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