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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"

19353 results found.

  1. Swift-BAT detection of a bright GRB 050326
  2. GRB050319, optical observations
  3. GRB050319, color indices
  4. GRB050319: RTT150 Optical Observations
  5. Swift-BAT detection of a bright outburst from SGR1806-20
  6. Swift-BAT trigger 112060 is not a real GRB
  7. GRB 050319: ROTSE-III Refined Analysis
  8. GRB 050318: Swift-BAT refined analysis
  9. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  10. GRB 050319 R band observations
  11. GRB 050319: Swift-UVOT detection of the afterglow
  12. GRB 050315: Variability Analysis of Swift BAT Time History
  13. GRB050319: BR optical photometry
  14. GRB 050318: SWIFT-UVOT refined analysis
  15. GRB 050319: Swift-BAT refined analysis
  16. GRB050319,optical observation
  17. Swift Detection of GRB 050319
  18. GRB 050319: Detection of Possible Optical Counterpart
  19. GRB 050318: Swift/UVOT detection of afterglow emission
  20. GRB050318: Swift XRT position
  21. Swift-BAT detection of GRB 050318
  22. GRB050223: analysis of the XMM-Newton observation
  23. GRB 050306: ROTSE-III early limits
  24. GRB 050315: Swift-BAT further refined analysis
  25. GRB050315: Swift-BAT Refined analysis
  26. Non-detection of GRB050315 in ATCA Radio Observations
  27. GRB 050315: Swift XRT Position
  28. GRB 050315: Early Observations with Swift/UVOT
  29. Swift-BAT detection of GRB 050315
  30. GRB050223: No XMM-Newton OM detection of afterglow emission
  31. GRB050309: CONCAM pre-trigger and trigger coincident optical
  32. GRB 050126: Redshift determination
  33. Swift-BAT trigger 107873: No Swift XRT counterpart
  34. GRB 050306: Confirmation of X-ray afterglow
  35. GRB 050309, Early optical limits from RAPTOR
  36. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  37. GRB 050309 : Lulin R-band observation
  38. Swift 107873: P60 Optical Observations
  39. GRB 050306: CORRECTION to date of observation
  40. GRB 050306: No Swift UVOT Optical Counterpart Detected
  41. GRB 050306: Possible X-ray Afterglow Position from the Swift
  42. Swift trigger 107518: optical observation
  43. GRB 050306,optical observation
  44. GRB 050306: Swift-BAT detection of a long burst
  45. GRB050215B: Late-Time Swift UVOT Observations
  46. PROMPT VRcIc Observations of GRB 050223
  47. GRB 050223: optical observations
  48. GRB050223 XMM-Newton observation
  49. INTEGRAL detection of GRB 050223
  50. GRB050223: No Swift UVOT Detection of Afterglow Emission
  51. GRB050223: ROTSE-III Optical Observations
  52. GRB 050223 Swift/BAT detection of a burst
  53. GRB 050223: Swift XRT Position
  54. GRB050219b: CORRECTION to time of UVOT observations
  55. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  56. GRB 050219b: CORRECTION to refined XRT position
  57. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  58. GRB 050219b: Refined XRT position
  59. GRB 050219b: Swift-BAT detection of a burst
  60. GRB 050219b: CORRECTION: Swift XRT Position
  61. GRB 050219b: Swift XRT Position
  62. GRB 050219a, optical observations
  63. GRB 050219a: Refined XRT position
  64. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  65. GRB 050219: Swift-BAT detection of a burst
  66. GRB050215b: Swift UVOT Detection of Afterglow Emission
  67. GRB 050219: Prompt X-ray position
  68. GRB 050215b: XRT confirmation of IR afterglow candidate
  69. GRB050215b: P60 Optical Observations
  70. GRB 050215b: Swift XRT Source Variability
  71. GRB 050215B: candidate afterglow
  72. GRB 050215b : Lulin follow-up observation
  73. GRB 050215b, BOOTES-2 simultaneous optical observations
  74. GRB 050215B: UKIRT K-band imaging
  75. GRB 050215b: Swift XRT Observations
  76. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  77. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  78. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  79. GRB050215B: ROTSE-III optical observations
  80. GRB050215A: ROTSE-III Optical Observations
  81. short/hard GRB 050202, optical observations
  82. GRB 050128: Radio observations
  83. Further analysis of the short Swift-BAT GRB 050202
  84. GRB 050202: Second epoch radio observations
  85. GRB050202: Radio Observations
  86. GRB 050202: Short burst detected by Swift-BAT
  87. SGR1806-20: Swift-BAT detection of a large normal burst
  88. GRB050128: Faulkes Telescope South observations
  89. GRB050128,optical observations
  90. GRB050126: Updated Swift XRT Position
  91. GRB 050126: Radio Observations
  92. GRB050128 Swift-BAT observations
  93. GRB 050128: Swift XRT prompt afterglow position
  94. GRB 050124: K-band afterglow observations
  95. GRB050126: MASTER optical limit for KECK OT
  96. GRB050126: Burst Parameters Measured by BAT
  97. GRB050126: MASTER optical observations
  98. GRB 050126: Prompt XRT detection and localization
  99. GRB050124: No Swift UVOT Detection of Afterglow Emission
  100. GRB 050117a: Radio Observations

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