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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 081011: Swift XRT refined analysis
  2. GRB 081016B: Swift-XRT Team refined Analysis
  3. GRB 081016B: Enhanced Swift-XRT position
  4. GRB 081016B: ROTSE-III Optical Limits
  5. GRB 081016B: Swift detection of a burst
  6. GRB 081011: Enhanced Swift-XRT position
  7. GRB 081016: Swift-XRT candidate afterglow detection
  8. Swift detection of flare on CC Eri
  9. GRB 081016: A long GRB discovered by INTEGRAL
  10. Trigger 331721 Due to Swift startracker loss-of-lock
  11. Detection of flare star Algol in Swift-BAT slew data
  12. GRB 081009: Fermi GBM detection
  13. GRB 081012: GROND upper limits
  14. GRB 081008: Galaxy associated with z=1.967 absorber
  15. Swift-BAT triggered on the flare star Algol
  16. GRB 081012: Fermi GBM detection
  17. GRB 081007 and GRB 081007B: Fermi GBM detection
  18. GRB 080430: optical observations
  19. GRB 081008 optical upper limit
  20. GRB 081012: Observations from NOT
  21. GRB 081012: Swift/UVOT analysis of initial observations
  22. GRB 081012: Swift/XRT detection
  23. GRB 081012, Swift-BAT refined analysis
  24. GRB 081012: ROTSE-III Optical Limits
  25. GRB 081012: Swift detection of a burst
  26. Revised table for GRB 081011 UVOT detections
  27. GRB081011: UVOT detection of an optical afterglow
  28. GRB 081011: Swift/XRT detection
  29. GRB 081011, Swift-BAT refined analysis
  30. GRB 081008, SMARTS optical/IR afterglow observations
  31. GRB 081011: Swift detection of a burst
  32. GRB 081007: Radio Detection
  33. Konus-Wind observation of GRB 081001
  34. GRB 081007: Rapid PROMPT Detections
  35. GRB 081008, Swift-BAT refined analysis
  36. GRB 081008: VLT redshift confirmation
  37. GRB 081008: Swift-XRT Refined Analysis
  38. GRB081008: Swift/UVOT observations
  39. GRB 081008: Enhanced Swift-XRT position
  40. GRB 081008: Gemini-South Absorption Redshiftt
  41. GRB 081008: VLT/FORS2 spectroscopy
  42. GRB 081008: Swift detection of a burst with optical afterglow
  43. GRB 081008: ROTSE-III Detection of Optical Counterpart
  44. GRB081006B: Fermi GBM detection
  45. GRB081006: Fermi GBM detection
  46. GRB081007: Swift/UVOT Observations
  47. GRB 081007, SMARTS optical afterglow observations
  48. GRB 081007, Swift-BAT refined analysis
  49. GRB 081007: Early RAPTOR measurements of optical counterpart
  50. GRB 081007: Swift-XRT Team refined analysis
  51. GRB 081007: Gemini-south redshift
  52. GRB 081007: Enhanced Swift-XRT position
  53. GRB 081007, Faulkes Telescope North optical observations
  54. GRB 081007, SMARTS optical/IR afterglow observations
  55. GRB 081007: REM NIR and optical counterpart
  56. GRB 081007: Swift detection of a burst with optical afterglow
  57. GRB081003C: GLAST Burst Monitor detection
  58. Fermi GBM detection of additional bursts from AXP 1E1547.0-5408
  59. INTEGRAL ToO observation of the AXP 1E 1547.0-5408
  60. GRB 081003B: TAROT Calern observatory optical observations
  61. AXP 1E 1547.0-5408: Swift/UVOT Upper Limits
  62. GRB 081003B: Swift-XRT upper limit
  63. GRB 081003A: OSN optical observations
  64. GRB 081001: Further observations from OSN
  65. AXP 1E1547.0-5408: Swift-XRT Team refined analysis
  66. GRB081003B: Optical limits from Spain
  67. GRB 081003A: Swift-XRT Team position and analysis
  68. Swift-BAT refined analysis of AXP 1E1547.0-5408 (Trigger 330353)
  69. GRB 081003B: a long GRB detected with INTEGRAL
  70. GRB 080928: Fermi GBM detection
  71. AXP 1E1547.0-5408 (SGR 1550-5418): Fermi GBM detection
  72. GRB 081003: A long GRB discovered by INTEGRAL
  73. SGR 1550-5418 = AXP 1E1547.0-5408 (Trigger 330353)
  74. Swift discovery of a new Soft Gamma Repeater SGR 1550-5418
  75. Trigger 330353: Swift detection of a Galactic short soft burst
  76. GRB 081001: Observations from OSN
  77. GRB 080925: Suzaku WAM observation of the prompt emission
  78. GRB 081001: Swift UVOT Observations
  79. GRB 081001: Swift-XRT position
  80. GRB081001: optical limit from ASH-Centurion
  81. GRB081001: SuperAGILE Localization of a long GRB
  82. GRB080928: redshift retraction
  83. GRB 080928: Watcher observations
  84. GRB 080927: Fermi GBM detection
  85. GRB 080928: VLT redshift
  86. GRB080928: Gemini-South Absorption Redshift
  87. GRB 080928: Swift-XRT refined analysis
  88. GRB 080928: Swift/UVOT observations
  89. GRB 080928, Swift-BAT final refined analysis
  90. GRB 080928: GROND DETECTION
  91. GRB 080928: Enhanced Swift-XRT position
  92. GRB 080928, Swift-BAT initial refined analysis
  93. GRB 080928A: ROTSE-III Confirmation of Optical Counterpart
  94. GRB 080928: Swift detection of a burst with an optical counterpart
  95. GRB 080925: Fermi GBM Detection
  96. GRB 080920: Fermi GBM detection
  97. GRB080922, optical upper limit
  98. Swift-BAT trigger 325707 is not a GRB
  99. Swift trigger 325707: Swift/UVOT Upper Limits
  100. Swift trigger 325707: Swift-XRT upper limit

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