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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"

36147 results found.

  1. GRB 050408: ROTSE-III Optical Limits
  2. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  3. GRB050408: MASTER optical observations
  4. GRB050401: Radio Detection
  5. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  6. GRB 050406: Magellan optical observations
  7. GRB 050406: early Swift XRT analysis results
  8. GRB 050406 BAT refined analysis
  9. GRB 050406: Early observations with Swift-UVOT
  10. GRB 050406: Swift XRT Position
  11. Swift-BAT detection of GRB 050406
  12. Konus-Wind observation of GRB 050401
  13. GRB050401: Radio observation at 610 MHz with GMRT
  14. GRB 050401: VLT spectroscopic redshift
  15. GRB 050401 Optical Observations
  16. GRB 050401 BAT refined analysis
  17. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  18. GRB050401: TNG R-band observation
  19. GRB 050402A: IR Analysis
  20. GRB 050402A: IR Observations
  21. GRB 050402: Early observations with Swift-UVOT
  22. Swift Trigger 113225: P60 Observations
  23. GRB 050401: Optical afterglow confirmed
  24. GRB 050401: Optical afterglow candidate
  25. Swift-BAT detection of GRB 050401
  26. GRB 050401: Prompt XRT position
  27. Retraction of three Swift GRB triggers
  28. GRB050331: No Afterglow Detected
  29. Swift-BAT detection of GRB 050331b
  30. GRB 050331: Swift UVOT Source
  31. Swift-BAT detection of GRB 050331
  32. GRB 050331: Swift XRT Position
  33. GRB050319: radio observation
  34. Konus-Wind observation of GRB 050326
  35. GRB 050326: Early observations with Swift-UVOT
  36. GRB 050326 XMM-Newton observation
  37. GRB 050326 : Planned XMM-Newton observation
  38. GRB 050326: Swift XRT Position
  39. GRB050326: optical limit 33min before GRB
  40. GRB 050326 BAT refined analysis
  41. GRB050326: delayed XRT observation
  42. Swift-BAT detection of a bright GRB 050326
  43. GRB050319, color indices
  44. GRB050319: RTT150 Optical Observations
  45. Swift-BAT trigger 112060 is not a real GRB
  46. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  47. GRB 050319: ROTSE-III Refined Analysis
  48. GRB 050318: Swift-BAT refined analysis
  49. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  50. GRB050319: VLA Observations
  51. GRB 050319 R band observations
  52. GRB 050319: Swift-UVOT detection of the afterglow
  53. GRB 050315: Variability Analysis of Swift BAT Time History
  54. GRB050319: Radio Observations
  55. GRB 050319: NIR afterglow candidate
  56. GRB 050319:Near IR afterglow
  57. GRB 050318: SWIFT-UVOT refined analysis
  58. GRB 050318: Absorption redshift from Magellan
  59. GRB 050319: Optical observation
  60. GRB 050319 : Confirmation of optical afterglow decay
  61. GRB 050319: Swift-BAT refined analysis
  62. GRB050319,optical observation
  63. Swift Detection of GRB 050319
  64. GRB 050319: Detection of Possible Optical Counterpart
  65. GRB 050318: Swift/UVOT detection of afterglow emission
  66. GRB 050318: Magellan optical afterglow identification
  67. GRB050318: Swift XRT position
  68. RXTE Observations of GRB050318
  69. Swift-BAT detection of GRB 050318
  70. GRB 050315, SMARTS optical afterglow decay
  71. GRB050316: MASTER before, simultanious and follow up optical
  72. GRB 050306: ROTSE-III early limits
  73. GRB050316: MASTER optical observations
  74. GRB 050315: Swift-BAT further refined analysis
  75. GRB 050315, SMARTS optical/IR afterglow observations
  76. GRB 050315 I-band observations
  77. GRB050315: Radio afterglow
  78. GRB 050315: Absorption redshift
  79. GRB 050315: Optical afterglow identification
  80. GRB050315: Swift-BAT Refined analysis
  81. Non-detection of GRB050315 in ATCA Radio Observations
  82. GRB 050315: Swift XRT Position
  83. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  84. GRB 050315: Early Observations with Swift/UVOT
  85. Swift-BAT detection of GRB 050315
  86. GRB 050306: Radio Observations
  87. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  88. GRB050309: CONCAM pre-trigger and trigger coincident optical
  89. GRB 050306: optical afterglow
  90. GRB 050126: Redshift determination
  91. Swift-BAT trigger 107873: No Swift XRT counterpart
  92. GRB 050306: Confirmation of X-ray afterglow
  93. GRB 050309, Early optical limits from RAPTOR
  94. GRB 050306: further TAROT optical data
  95. GRB050309: Early optical limit from P60
  96. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  97. GRB 050309 : Lulin R-band observation
  98. Swift 107873: P60 Optical Observations
  99. GRB 050306: CORRECTION to date of observation
  100. GRB 050306: R-band observations

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