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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"

24672 results found.

  1. Retraction of three Swift GRB triggers
  2. GRB050331: No Afterglow Detected
  3. Swift-BAT detection of GRB 050331b
  4. GRB 050331: Swift UVOT Source
  5. Swift-BAT detection of GRB 050331
  6. GRB 050326: Early observations with Swift-UVOT
  7. GRB 050326 XMM-Newton observation
  8. GRB 050326: Swift XRT Position
  9. GRB 050326 BAT refined analysis
  10. GRB050326: delayed XRT observation
  11. GRB050319, color indices
  12. GRB050319: optical observation, March 20-22
  13. GRB050319: RTT150 Optical Observations
  14. Swift-BAT trigger 112060 is not a real GRB
  15. GRB 050318: Swift-BAT refined analysis
  16. GRB050319: VLA Observations
  17. GRB050319: radio observation
  18. GRB 050319: Swift-UVOT detection of the afterglow
  19. GRB 050315: Variability Analysis of Swift BAT Time History
  20. GRB050319: Radio Observations
  21. GRB 050319: NIR afterglow candidate
  22. GRB 050319:Near IR afterglow
  23. GRB 050318: SWIFT-UVOT refined analysis
  24. GRB 050319 : Confirmation of optical afterglow decay
  25. GRB 050319: Swift-BAT refined analysis
  26. GRB050319,optical observation
  27. GRB 050318: Swift/UVOT detection of afterglow emission
  28. RXTE Observations of GRB050318
  29. GRB050223: analysis of the XMM-Newton observation
  30. GRB050316: MASTER before, simultanious and follow up optical
  31. GRB 050306: ROTSE-III early limits
  32. GRB050316: MASTER optical observations
  33. GRB 050315: Swift-BAT further refined analysis
  34. GRB 050315 I-band observations
  35. GRB050315: Radio afterglow
  36. GRB050315: Swift-BAT Refined analysis
  37. Non-detection of GRB050315 in ATCA Radio Observations
  38. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  39. GRB 050315: Early Observations with Swift/UVOT
  40. GRB 050306: Radio Observations
  41. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  42. GRB 050306: optical afterglow
  43. Swift-BAT trigger 107873: No Swift XRT counterpart
  44. GRB 050306: Confirmation of X-ray afterglow
  45. GRB 050306: further TAROT optical data
  46. GRB050309: Early optical limit from P60
  47. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  48. GRB 050309 : Lulin R-band observation
  49. Swift 107873: P60 Optical Observations
  50. GRB 050306: R-band observations
  51. GRB 050306: REM optical-infrared observations
  52. GRB 050306: Possible X-ray Afterglow Position from the Swift
  53. GRB 050306: TAROT optical observations
  54. GRB 050306,optical observation
  55. Ongoing activity of SGR 1806-20 after the giant flare
  56. GRB050215B: Late-Time Swift UVOT Observations
  57. PROMPT VRcIc Observations of GRB 050223
  58. XRF/GRB 050215B: Radio Observations
  59. XMM-Newton Images of GRB 050223
  60. GRB 050219b: candidate NIR afterglow
  61. Confirmed XRF nature for GRB050215b
  62. GRB050223 XMM-Newton observation
  63. INTEGRAL detection of GRB 050223
  64. GRB050223: ROTSE-III Optical Observations
  65. GRB 050223 Swift/BAT detection of a burst
  66. GRB 050223: Swift XRT Position
  67. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  68. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  69. GRB 050219a: Optical observations from LCO
  70. GRB 050219b: Optical and near-IR observations from LCO
  71. GRB 050219b: Swift-BAT detection of a burst
  72. GRB 050219b: CORRECTION: Swift XRT Position
  73. GRB 050219b: Swift XRT Position
  74. GRB 050219: Swift-BAT detection of a burst
  75. GRB 050215b: XRT confirmation of IR afterglow candidate
  76. GRB050215b: P60 Optical Observations
  77. GRB 050215b: Swift XRT Source Variability
  78. GRB 050215B: candidate afterglow
  79. GRB 050215b : Lulin follow-up observation
  80. GRB 050215b, BOOTES-2 simultaneous optical observations
  81. GRB050215A: ROTSE-III Optical Observations
  82. GRB050209: TAROT optical observations
  83. GRB 050209(=U11568): Duration and spectrum
  84. GRB050209: REM optical observations
  85. GRB 050209 I-band observation
  86. GRB 050209 Optical observations
  87. GRB050209: P60 Optical Observations
  88. GRB 050128: Radio observations
  89. Further analysis of the short Swift-BAT GRB 050202
  90. GRB 050202: Short burst detected by Swift-BAT
  91. GRB 050128 Optical observation with REM
  92. SGR1806-20: Swift-BAT detection of a large normal burst
  93. GRB 050128: near-infrared observations with REM
  94. GRB050128,optical observations
  95. GRB050128 Swift-BAT observations
  96. GRB 050128: Swift XRT prompt afterglow position
  97. GRB050126: MASTER optical limit for KECK OT
  98. GRB050126: Burst Parameters Measured by BAT
  99. GRB050126: MASTER optical observations
  100. GRB 050124 I-band observation

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