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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"

27400 results found.

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

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