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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 150211A: KAIT Optical Upper Limit
  2. GRB 150211A: Mondy optical upper limit
  3. GRB 150211A: Swift-XRT refined Analysis
  4. GRB 150210A: Tiled Swift observations
  5. Konus-Wind observation of GRB 150210A
  6. IPN Triangulation of GRB 150210A
  7. GRB 150210A: Fermi-LAT detection
  8. GRB 150211A: RATIR Optical and NIR Observations
  9. GRB 150211A: No afterglow detection in the Swift/UVOT initial observation
  10. GRB 150211A: Swift-XRT observations
  11. GRB 150211A: Swift detection of a burst
  12. GRB 150211A: MASTER early optical observations
  13. GRB 150210A: Fermi GBM detection
  14. GRB 150101B/ Swift J123205.1-105602: Second epoch Chandra observations
  15. GRB 150204A: GROND observations
  16. GRB 150202B: Swift/XRT afterglow confirmation
  17. GRB 150204A: Swift/XRT afterglow confirmation
  18. Konus-Wind observation of GRB 150206A
  19. GRB 150206A: Swift-BAT refined analysis
  20. GRB 150203A iTelescope observation
  21. GRB 150206A: Swift/UVOT Detection
  22. GRB 150206A: Swift-XRT refined Analysis
  23. Konus-Wind observation of GRB 150202B
  24. GRB 140206B: Continued iPTF Observations
  25. GRB 150206A: VLT/X-shooter redshift
  26. GRB 150206A: GROND afterglow observations
  27. GRB 150206A: Enhanced Swift-XRT position
  28. GRB 150206B: Fermi GBM detection
  29. Trigger 630047: Swift detection of 1RXS J180408.9-342058
  30. GRB 150206B: iPTF Optical Observations
  31. GRB 150206A: MAXI/GSC detection
  32. GRB 150206A: Swift detection of a burst with an optical afterglow
  33. GRB 150204A: LCOGT-Sutherland and Siding Springs observations
  34. GRB 150204A: Swift/UVOT Upper Limits
  35. GRB 150203A: Swift-BAT refined analysis
  36. GRB 150204A: Swift-XRT observations
  37. GRB 150204A: Fermi GBM detection
  38. GRB 150204A: Swift ToO observations
  39. GRB 150204A BAT refined analysis
  40. GRB 150202B: Swift XRT/UVOT observations
  41. GRB 150204A found in ground analysis of Swift-BAT data
  42. Swift Trigger 629693 was a noise event
  43. GRB 150203A: RAPTOR Limits Beginning at the Gamma-Ray Emitting Interval
  44. GRB 150202A, Swift-BAT refined analysis
  45. GRB 150203A: Swift/UVOT Upper Limits
  46. GRB 150203A: ISON-NM early optical limit
  47. IPN Triangulation of GRB 150202B
  48. GRB 150203A: Swift-XRT refined Analysis
  49. GRB 150202B: Tiled Swift observations
  50. GRB 150203A: MITSuME Okayama upper limits
  51. Swift Trigger 629693: probably not real
  52. Fermi GBM trigger 150202624 is not a GRB
  53. GRB 150202A: Swift/UVOT Upper Limits
  54. GRB 150203A: REM optical and NIR observations
  55. GRB 150202A: Swift-XRT refined Analysis
  56. GRB 150203A: Fermi GBM observation
  57. GRB 150202B: Fermi GBM detection
  58. GRB 150203A: TAROT La Silla observatory optical observations
  59. GRB 150203A: GROND Upper limits
  60. GRB 150202B: Fermi-LAT detection
  61. GRB 150203A: Enhanced Swift-XRT position
  62. GRB 150203A: RATIR Optical and NIR Observations
  63. GRB 150202A: Enhanced Swift-XRT position
  64. GRB 150202A: GROND Upper limits
  65. GRB 150203A: P60 observations
  66. GRB 150203A: KAIT Optical Upper Limit
  67. GRB 150203A: Prompt enhanced Swift-XRT position
  68. GRB 150203A: Swift detection of a burst
  69. GRB 150202A: Swift detection of a burst
  70. GRB 150201A: Swift/UVOT Upper Limits
  71. GRB 150201A, Swift-BAT refined analysis
  72. Konus-Wind observation of GRB 150201A
  73. GRB 150201A: GROND upper limits
  74. GRB 150201A: Swift-XRT refined Analysis
  75. GRB 150201A: Fermi GBM observation
  76. GRB 150201A: Enhanced Swift-XRT position
  77. GRB 150201A: Swift detection of a burst
  78. Swift Trigger 629206 is likely 1RXS J180408.9-342058
  79. GRB 150120B: Khureltogot optical observations
  80. GRB 150128A: MASTER OT detction during inspection
  81. GRB 150127B: Fermi GBM detection
  82. Konus-Wind observation of GRB 150127B
  83. GRB 150123A: MASTER inspection
  84. GRB 150120A: 9.8 GHz VLA upper limit
  85. IPN Triangulation of GRB 150127B
  86. IPN Triangulation of GRB 150127A
  87. GRB 150120A: Gemini-N imaging and host redshift
  88. Konus-Wind observation of GRB 150126A reveals its ultra-long nature
  89. GRB 150127A: Fermi-LAT detection
  90. GRB150127A: Fermi GBM Detection
  91. Swift Trigger 628458 likely not astrophysical
  92. GRB 150126A: Fermi GBM Detection
  93. GRB 150126A: MAXI/GSC afterglow candidate detection
  94. Konus-Wind observation of GRB 150123A
  95. GRB 150120A: possible AMI 15 GHz detection
  96. GRB 150123A: Swift/UVOT observations
  97. GRB 150123A: Swift-XRT observations
  98. GRB 150120B: Mondy optical observations
  99. GRB 150123A Tiled Swift observations
  100. GRB 150123A: MAXI/GSC detection

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