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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. GRB 081012: Swift-XRT Refined Analysis
  2. Swift trigger 332287 is not a GRB
  3. Swift detection of a possible burst (trigger 332287)
  4. GRB 081012 - Enhanced Swift XRT position
  5. GRB 081017, Swift-BAT refined analysis
  6. GRB 081017: REM early observations
  7. GRB 081017: Swift detection of a burst
  8. GRB 081016B, Swift-BAT refined analysis
  9. GRB 081016B: Swift/UVOT Upper Limits
  10. GRB 081011: Swift XRT refined analysis
  11. GRB 081016B: Swift-XRT Team refined Analysis
  12. GRB 081016B: Enhanced Swift-XRT position
  13. GRB 081016B: ROTSE-III Optical Limits
  14. GRB 081016B: Swift detection of a burst
  15. GRB 081011: Enhanced Swift-XRT position
  16. GRB 081016: Swift-XRT candidate afterglow detection
  17. Swift detection of flare on CC Eri
  18. GRB 081016: A long GRB discovered by INTEGRAL
  19. Trigger 331721 Due to Swift startracker loss-of-lock
  20. Detection of flare star Algol in Swift-BAT slew data
  21. GRB 081009: Fermi GBM detection
  22. GRB 081012: GROND upper limits
  23. GRB 081008: Galaxy associated with z=1.967 absorber
  24. Swift-BAT triggered on the flare star Algol
  25. GRB 081012: Fermi GBM detection
  26. GRB 081007 and GRB 081007B: Fermi GBM detection
  27. GRB 080430: optical observations
  28. GRB 081008 optical upper limit
  29. GRB 081012: Observations from NOT
  30. GRB 081012: Swift/UVOT analysis of initial observations
  31. GRB 081012: Swift/XRT detection
  32. GRB 081012, Swift-BAT refined analysis
  33. GRB 081012: ROTSE-III Optical Limits
  34. GRB 081012: Swift detection of a burst
  35. Revised table for GRB 081011 UVOT detections
  36. GRB081011: UVOT detection of an optical afterglow
  37. GRB 081011: Swift/XRT detection
  38. GRB 081011, Swift-BAT refined analysis
  39. GRB 081008, SMARTS optical/IR afterglow observations
  40. GRB 081011: Swift detection of a burst
  41. GRB 081007: Radio Detection
  42. Konus-Wind observation of GRB 081001
  43. GRB 081007: Rapid PROMPT Detections
  44. GRB 081008, Swift-BAT refined analysis
  45. GRB 081008: VLT redshift confirmation
  46. GRB 081008: Swift-XRT Refined Analysis
  47. GRB081008: Swift/UVOT observations
  48. GRB 081008: Enhanced Swift-XRT position
  49. GRB 081008: Gemini-South Absorption Redshiftt
  50. GRB 081008: VLT/FORS2 spectroscopy
  51. GRB 081008: Swift detection of a burst with optical afterglow
  52. GRB 081008: ROTSE-III Detection of Optical Counterpart
  53. GRB081006B: Fermi GBM detection
  54. GRB081006: Fermi GBM detection
  55. GRB081007: Swift/UVOT Observations
  56. GRB 081007, SMARTS optical afterglow observations
  57. GRB 081007, Swift-BAT refined analysis
  58. GRB 081007: Early RAPTOR measurements of optical counterpart
  59. GRB 081007: Swift-XRT Team refined analysis
  60. GRB 081007: Gemini-south redshift
  61. GRB 081007: Enhanced Swift-XRT position
  62. GRB 081007, Faulkes Telescope North optical observations
  63. GRB 081007, SMARTS optical/IR afterglow observations
  64. GRB 081007: REM NIR and optical counterpart
  65. GRB 081007: Swift detection of a burst with optical afterglow
  66. GRB081003C: GLAST Burst Monitor detection
  67. Fermi GBM detection of additional bursts from AXP 1E1547.0-5408
  68. INTEGRAL ToO observation of the AXP 1E 1547.0-5408
  69. GRB 081003B: TAROT Calern observatory optical observations
  70. AXP 1E 1547.0-5408: Swift/UVOT Upper Limits
  71. GRB 081003B: Swift-XRT upper limit
  72. GRB 081003A: OSN optical observations
  73. GRB 081001: Further observations from OSN
  74. AXP 1E1547.0-5408: Swift-XRT Team refined analysis
  75. GRB081003B: Optical limits from Spain
  76. GRB 081003A: Swift-XRT Team position and analysis
  77. Swift-BAT refined analysis of AXP 1E1547.0-5408 (Trigger 330353)
  78. GRB 081003B: a long GRB detected with INTEGRAL
  79. GRB 080928: Fermi GBM detection
  80. AXP 1E1547.0-5408 (SGR 1550-5418): Fermi GBM detection
  81. GRB 081003: A long GRB discovered by INTEGRAL
  82. SGR 1550-5418 = AXP 1E1547.0-5408 (Trigger 330353)
  83. Swift discovery of a new Soft Gamma Repeater SGR 1550-5418
  84. Trigger 330353: Swift detection of a Galactic short soft burst
  85. GRB 081001: Observations from OSN
  86. GRB 080925: Suzaku WAM observation of the prompt emission
  87. GRB 081001: Swift UVOT Observations
  88. GRB 081001: Swift-XRT position
  89. GRB081001: optical limit from ASH-Centurion
  90. GRB081001: SuperAGILE Localization of a long GRB
  91. GRB080928: redshift retraction
  92. GRB 080928: Watcher observations
  93. GRB 080927: Fermi GBM detection
  94. GRB 080928: VLT redshift
  95. GRB080928: Gemini-South Absorption Redshift
  96. GRB 080928: Swift-XRT refined analysis
  97. GRB 080928: Swift/UVOT observations
  98. GRB 080928, Swift-BAT final refined analysis
  99. GRB 080928: GROND DETECTION
  100. GRB 080928: Enhanced Swift-XRT position

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