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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"

24881 results found.

  1. Swift-BAT detection of GRB 050406
  2. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  3. GRB 050401: VLT spectroscopic redshift
  4. GRB 050401 BAT refined analysis
  5. GRB050401: TNG R-band observation
  6. GRB 050402: Early observations with Swift-UVOT
  7. Swift Trigger 113225: P60 Observations
  8. GRB 050401: Optical afterglow confirmed
  9. GRB 050401: Prompt XRT position
  10. Retraction of three Swift GRB triggers
  11. GRB050331: No Afterglow Detected
  12. Swift-BAT detection of GRB 050331b
  13. GRB 050331: Swift UVOT Source
  14. Swift-BAT detection of GRB 050331
  15. GRB 050326: Early observations with Swift-UVOT
  16. GRB 050326 XMM-Newton observation
  17. GRB 050326: Swift XRT Position
  18. GRB 050326 BAT refined analysis
  19. GRB050326: delayed XRT observation
  20. GRB050319, color indices
  21. GRB050319: optical observation, March 20-22
  22. GRB050319: RTT150 Optical Observations
  23. Swift-BAT trigger 112060 is not a real GRB
  24. GRB 050318: Swift-BAT refined analysis
  25. GRB050319: VLA Observations
  26. GRB050319: radio observation
  27. GRB 050319: Swift-UVOT detection of the afterglow
  28. GRB 050315: Variability Analysis of Swift BAT Time History
  29. GRB050319: Radio Observations
  30. GRB 050319: NIR afterglow candidate
  31. GRB 050319:Near IR afterglow
  32. GRB 050318: SWIFT-UVOT refined analysis
  33. GRB 050319 : Confirmation of optical afterglow decay
  34. GRB 050319: Swift-BAT refined analysis
  35. GRB050319,optical observation
  36. GRB 050318: Swift/UVOT detection of afterglow emission
  37. RXTE Observations of GRB050318
  38. GRB050223: analysis of the XMM-Newton observation
  39. GRB050316: MASTER before, simultanious and follow up optical
  40. GRB 050306: ROTSE-III early limits
  41. GRB050316: MASTER optical observations
  42. GRB 050315: Swift-BAT further refined analysis
  43. GRB 050315 I-band observations
  44. GRB050315: Radio afterglow
  45. GRB050315: Swift-BAT Refined analysis
  46. Non-detection of GRB050315 in ATCA Radio Observations
  47. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  48. GRB 050315: Early Observations with Swift/UVOT
  49. GRB 050306: Radio Observations
  50. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  51. GRB 050306: optical afterglow
  52. Swift-BAT trigger 107873: No Swift XRT counterpart
  53. GRB 050306: Confirmation of X-ray afterglow
  54. GRB 050306: further TAROT optical data
  55. GRB050309: Early optical limit from P60
  56. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  57. GRB 050309 : Lulin R-band observation
  58. Swift 107873: P60 Optical Observations
  59. GRB 050306: R-band observations
  60. GRB 050306: REM optical-infrared observations
  61. GRB 050306: Possible X-ray Afterglow Position from the Swift
  62. GRB 050306: TAROT optical observations
  63. GRB 050306,optical observation
  64. Ongoing activity of SGR 1806-20 after the giant flare
  65. GRB050215B: Late-Time Swift UVOT Observations
  66. PROMPT VRcIc Observations of GRB 050223
  67. XRF/GRB 050215B: Radio Observations
  68. XMM-Newton Images of GRB 050223
  69. GRB 050219b: candidate NIR afterglow
  70. Confirmed XRF nature for GRB050215b
  71. GRB050223 XMM-Newton observation
  72. INTEGRAL detection of GRB 050223
  73. GRB050223: ROTSE-III Optical Observations
  74. GRB 050223 Swift/BAT detection of a burst
  75. GRB 050223: Swift XRT Position
  76. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  77. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  78. GRB 050219a: Optical observations from LCO
  79. GRB 050219b: Optical and near-IR observations from LCO
  80. GRB 050219b: Swift-BAT detection of a burst
  81. GRB 050219b: CORRECTION: Swift XRT Position
  82. GRB 050219b: Swift XRT Position
  83. GRB 050219: Swift-BAT detection of a burst
  84. GRB 050215b: XRT confirmation of IR afterglow candidate
  85. GRB050215b: P60 Optical Observations
  86. GRB 050215b: Swift XRT Source Variability
  87. GRB 050215B: candidate afterglow
  88. GRB 050215b : Lulin follow-up observation
  89. GRB 050215b, BOOTES-2 simultaneous optical observations
  90. GRB050215A: ROTSE-III Optical Observations
  91. GRB050209: TAROT optical observations
  92. GRB 050209(=U11568): Duration and spectrum
  93. GRB050209: REM optical observations
  94. GRB 050209 I-band observation
  95. GRB 050209 Optical observations
  96. GRB050209: P60 Optical Observations
  97. GRB 050128: Radio observations
  98. Further analysis of the short Swift-BAT GRB 050202
  99. GRB 050202: Short burst detected by Swift-BAT
  100. GRB 050128 Optical observation with REM

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