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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"

19582 results found.

  1. Konus-Wind observation of GRB 050401
  2. GRB050401: Radio observation at 610 MHz with GMRT
  3. GRB 050401: VLT spectroscopic redshift
  4. GRB 050401 Optical Observations
  5. GRB050401: Maidanak optical observation
  6. GRB 050401 BAT refined analysis
  7. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  8. GRB 050402A: IR Observations
  9. GRB 050402: Early observations with Swift-UVOT
  10. Swift Trigger 113225: P60 Observations
  11. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  12. GRB 050401: Optical afterglow candidate
  13. Swift-BAT detection of GRB 050401
  14. GRB 050401: Prompt XRT position
  15. Retraction of three Swift GRB triggers
  16. Swift-BAT detection of GRB 050331b
  17. GRB 050331: Swift UVOT Source
  18. Swift-BAT detection of GRB 050331
  19. GRB 050331: Swift XRT Position
  20. Swift Data Publicly Available Starting April 5, 2005
  21. Konus-Wind observation of GRB 050326
  22. GRB050326: optical limit
  23. GRB 050326: Early observations with Swift-UVOT
  24. GRB 050326 XMM-Newton observation
  25. GRB 050326 : Planned XMM-Newton observation
  26. GRB 050326: Swift XRT Position
  27. GRB050326: optical limit 33min before GRB
  28. GRB 050326 BAT refined analysis
  29. GRB050326: delayed XRT observation
  30. Swift-BAT detection of a bright GRB 050326
  31. GRB050319, optical observations
  32. GRB050319, color indices
  33. GRB050319: RTT150 Optical Observations
  34. Swift-BAT detection of a bright outburst from SGR1806-20
  35. Swift-BAT trigger 112060 is not a real GRB
  36. GRB 050319: ROTSE-III Refined Analysis
  37. GRB 050318: Swift-BAT refined analysis
  38. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  39. GRB 050319 R band observations
  40. GRB 050319: Swift-UVOT detection of the afterglow
  41. GRB 050315: Variability Analysis of Swift BAT Time History
  42. GRB050319: BR optical photometry
  43. GRB 050318: SWIFT-UVOT refined analysis
  44. GRB 050319: Swift-BAT refined analysis
  45. GRB050319,optical observation
  46. Swift Detection of GRB 050319
  47. GRB 050319: Detection of Possible Optical Counterpart
  48. GRB 050318: Swift/UVOT detection of afterglow emission
  49. GRB050318: Swift XRT position
  50. Swift-BAT detection of GRB 050318
  51. GRB050223: analysis of the XMM-Newton observation
  52. GRB 050306: ROTSE-III early limits
  53. GRB 050315: Swift-BAT further refined analysis
  54. GRB050315: Swift-BAT Refined analysis
  55. Non-detection of GRB050315 in ATCA Radio Observations
  56. GRB 050315: Swift XRT Position
  57. GRB 050315: Early Observations with Swift/UVOT
  58. Swift-BAT detection of GRB 050315
  59. GRB050223: No XMM-Newton OM detection of afterglow emission
  60. GRB050309: CONCAM pre-trigger and trigger coincident optical
  61. GRB 050126: Redshift determination
  62. Swift-BAT trigger 107873: No Swift XRT counterpart
  63. GRB 050306: Confirmation of X-ray afterglow
  64. GRB 050309, Early optical limits from RAPTOR
  65. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  66. GRB 050309 : Lulin R-band observation
  67. Swift 107873: P60 Optical Observations
  68. GRB 050306: CORRECTION to date of observation
  69. GRB 050306: No Swift UVOT Optical Counterpart Detected
  70. GRB 050306: Possible X-ray Afterglow Position from the Swift
  71. Swift trigger 107518: optical observation
  72. GRB 050306,optical observation
  73. GRB 050306: Swift-BAT detection of a long burst
  74. GRB050215B: Late-Time Swift UVOT Observations
  75. PROMPT VRcIc Observations of GRB 050223
  76. GRB 050223: optical observations
  77. GRB050223 XMM-Newton observation
  78. INTEGRAL detection of GRB 050223
  79. GRB050223: No Swift UVOT Detection of Afterglow Emission
  80. GRB050223: ROTSE-III Optical Observations
  81. GRB 050223 Swift/BAT detection of a burst
  82. GRB 050223: Swift XRT Position
  83. GRB050219b: CORRECTION to time of UVOT observations
  84. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  85. GRB 050219b: CORRECTION to refined XRT position
  86. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  87. GRB 050219b: Refined XRT position
  88. GRB 050219b: Swift-BAT detection of a burst
  89. GRB 050219b: CORRECTION: Swift XRT Position
  90. GRB 050219b: Swift XRT Position
  91. GRB 050219a, optical observations
  92. GRB 050219a: Refined XRT position
  93. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  94. GRB 050219: Swift-BAT detection of a burst
  95. GRB050215b: Swift UVOT Detection of Afterglow Emission
  96. GRB 050219: Prompt X-ray position
  97. GRB 050215b: XRT confirmation of IR afterglow candidate
  98. GRB050215b: P60 Optical Observations
  99. GRB 050215b: Swift XRT Source Variability
  100. GRB 050215B: candidate afterglow

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