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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"
  1. GRB050408: REM NIR and Optical observation
  2. GRB 050408: Moderate-resolution Gemini Spectroscopy
  3. GRB 050408,optical observation
  4. GRB 050408 Optical Observations
  5. GRB 050408: Emission and absorption redshift
  6. GRB 050408: Mercator Optical Observations
  7. GRB 050408: Magellan astrometry and photometry
  8. GRB 050408: First Optical observations with TFOSC at the RTT150
  9. GRB 050408: steepening of the optical decay
  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. GRB 050408: ROTSE-III Optical Limits
  16. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  17. GRB050408: MASTER optical observations
  18. GRB050401: Radio Detection
  19. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  20. GRB 050406: Magellan optical observations
  21. GRB 050406: early Swift XRT analysis results
  22. GRB 050406 BAT refined analysis
  23. GRB 050406: Early observations with Swift-UVOT
  24. GRB 050406: Swift XRT Position
  25. Swift-BAT detection of GRB 050406
  26. Konus-Wind observation of GRB 050401
  27. GRB050401: Radio observation at 610 MHz with GMRT
  28. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  29. GRB 050401: VLT spectroscopic redshift
  30. GRB 050401 Optical Observations
  31. GRB050401: Maidanak optical observation
  32. GRB 050401 BAT refined analysis
  33. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  34. GRB050401: TNG R-band observation
  35. GRB 050402A: IR Analysis
  36. GRB050402: XDSS counterpart
  37. GRB 050402A: IR Observations
  38. GRB 050402: Early observations with Swift-UVOT
  39. Swift Trigger 113225: P60 Observations
  40. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  41. GRB 050401: Optical afterglow confirmed
  42. GRB 050401: Optical afterglow candidate
  43. Swift-BAT detection of GRB 050401
  44. GRB 050401: Prompt XRT position
  45. Retraction of three Swift GRB triggers
  46. GRB050331: No Afterglow Detected
  47. Swift-BAT detection of GRB 050331b
  48. GRB 050331: Swift UVOT Source
  49. Swift-BAT detection of GRB 050331
  50. GRB 050331: Swift XRT Position
  51. Swift Data Publicly Available Starting April 5, 2005
  52. GRB050319: radio observation
  53. Konus-Wind observation of GRB 050326
  54. GRB050326: optical limit
  55. GRB 050326: Early observations with Swift-UVOT
  56. GRB 050326 XMM-Newton observation
  57. GRB 050326 : Planned XMM-Newton observation
  58. GRB 050326: Swift XRT Position
  59. GRB050326: optical limit 33min before GRB
  60. GRB 050326 BAT refined analysis
  61. GRB050326: delayed XRT observation
  62. Swift-BAT detection of a bright GRB 050326
  63. GRB050319, optical observations
  64. GRB050319, color indices
  65. GRB050319: optical observation, March 20-22
  66. GRB050319: RTT150 Optical Observations
  67. Swift-BAT detection of a bright outburst from SGR1806-20
  68. Swift-BAT trigger 112060 is not a real GRB
  69. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  70. GRB 050319: ROTSE-III Refined Analysis
  71. GRB 050318: Swift-BAT refined analysis
  72. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  73. GRB050319: VLA Observations
  74. GRB050319: radio observation
  75. GRB 050319 R band observations
  76. GRB 050319: Swift-UVOT detection of the afterglow
  77. GRB 050315: Variability Analysis of Swift BAT Time History
  78. GRB050319: Radio Observations
  79. GRB 050319: NIR afterglow candidate
  80. GRB 050319:Near IR afterglow
  81. GRB050319: BR optical photometry
  82. GRB 050318: SWIFT-UVOT refined analysis
  83. GRB 050318: Absorption redshift from Magellan
  84. GRB 050319: Optical observation
  85. GRB 050319 : Confirmation of optical afterglow decay
  86. GRB 050319: Swift-BAT refined analysis
  87. GRB050319,optical observation
  88. Swift Detection of GRB 050319
  89. GRB 050319: Detection of Possible Optical Counterpart
  90. GRB 050318: Swift/UVOT detection of afterglow emission
  91. GRB 050318: Magellan optical afterglow identification
  92. GRB050318: Swift XRT position
  93. RXTE Observations of GRB050318
  94. Swift-BAT detection of GRB 050318
  95. GRB 050315, SMARTS optical afterglow decay
  96. GRB050223: analysis of the XMM-Newton observation
  97. GRB050316: MASTER before, simultanious and follow up optical
  98. GRB 050306: ROTSE-III early limits
  99. GRB050316: MASTER optical observations
  100. GRB 050315: Swift-BAT further refined analysis

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