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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"

19547 results found.

  1. GRB 150301A: Swift detection of a short burst or new SGR
  2. Fermi GBM Observations of Magnetar 4U 0142+61
  3. Trigger 632888: Swift detection of the magnetar 4U 0142+61
  4. GRB 150222A: Further GROND Observations
  5. GRB 150220A: Swift ToO observations
  6. GRB 150222A: I-band observations from OSN
  7. GRB 150222A: Swift/UVOT Upper Limits
  8. Fermi GBM Observations of SGR 1935+2154
  9. GRB 150222A: GROND optical afterglow candidate
  10. GRB 150222A: Enhanced Swift-XRT position
  11. GRB 150222A: TNG optical observations
  12. SGR 1935+2154: Swift-BAT refined analysis
  13. GRB 150222A: Mondy optical observations
  14. GRB 150222A: Zadko observatory - Gingin optical observations
  15. GRB 150222A: Swift detection of a burst
  16. Swift detection of an outburst from SGR 1935+2154
  17. Trigger 631747: Swift detection of 4U 0614+09
  18. GRB 150213B: AAO photometry
  19. GRB 150219A: Swift ToO observations
  20. GRB 150213B: Enhanced Swift-XRT position
  21. GRB 150213B: Swift/UVOT Detection
  22. GRB 150213B: RATIR Optical and NIR Observations
  23. GRB 150213B: AAO optical observations
  24. GRB 150213B: optical detection from the NOT
  25. GRB 150212A: Swift/UVOT Observations
  26. GRB 150213B: Swift detection of a burst with an optical afterglow
  27. GRB 150212A: RATIR Optical and NIR Observations
  28. GRB 150212A: Khureltogot optical upper limit
  29. GRB 150212A: Skynet DSO14/GORT observations
  30. GRB 150212A: No Swift/UVOT detection in initial observation
  31. GRB 150212A: P60 Afterglow Retraction
  32. GRB 150210A: Swift-XRT observations
  33. GRB 150212A: Swift-XRT afterglow detection
  34. GRB150212A: P60 Afterglow Candidate
  35. GRB 150211A iTelescope observation
  36. GRB 150211A: Swift/UVOT Upper Limits
  37. GRB 150211A: Mondy optical upper limit
  38. GRB 150210A: Tiled Swift observations
  39. GRB 150210A: Fermi-LAT detection
  40. GRB 150211A: RATIR Optical and NIR Observations
  41. GRB 150211A: No afterglow detection in the Swift/UVOT initial observation
  42. GRB 150211A: Swift-XRT observations
  43. GRB 150204A: GROND observations
  44. GRB 150203A iTelescope observation
  45. GRB 150206A: Swift/UVOT Detection
  46. GRB 150206A: Swift-XRT refined Analysis
  47. GRB 150206A: GROND afterglow observations
  48. GRB 150206A: Enhanced Swift-XRT position
  49. Trigger 630047: Swift detection of 1RXS J180408.9-342058
  50. GRB 150206A: Swift detection of a burst with an optical afterglow
  51. GRB 150204A: Swift/UVOT Upper Limits
  52. GRB 150204A: Swift ToO observations
  53. Swift Trigger 629693 was a noise event
  54. GRB 150203A: RAPTOR Limits Beginning at the Gamma-Ray Emitting Interval
  55. GRB 150203A: Swift/UVOT Upper Limits
  56. GRB 150203A: ISON-NM early optical limit
  57. IPN Triangulation of GRB 150202B
  58. GRB 150203A: Swift-XRT refined Analysis
  59. GRB 150202B: Tiled Swift observations
  60. GRB 150203A: MITSuME Okayama upper limits
  61. Swift Trigger 629693: probably not real
  62. GRB 150202A: Swift/UVOT Upper Limits
  63. GRB 150203A: REM optical and NIR observations
  64. GRB 150203A: Fermi GBM observation
  65. GRB 150203A: TAROT La Silla observatory optical observations
  66. GRB 150203A: GROND Upper limits
  67. GRB 150202B: Fermi-LAT detection
  68. GRB 150203A: Enhanced Swift-XRT position
  69. GRB 150203A: RATIR Optical and NIR Observations
  70. GRB 150202A: Enhanced Swift-XRT position
  71. GRB 150202A: GROND Upper limits
  72. GRB 150203A: Swift detection of a burst
  73. GRB 150202A: Swift detection of a burst
  74. GRB 150201A: Swift/UVOT Upper Limits
  75. GRB 150201A, Swift-BAT refined analysis
  76. GRB 150201A: GROND upper limits
  77. GRB 150201A: Fermi GBM observation
  78. GRB 150201A: Enhanced Swift-XRT position
  79. GRB 150201A: Swift detection of a burst
  80. GRB 150120B: Khureltogot optical observations
  81. GRB 150120A: 9.8 GHz VLA upper limit
  82. IPN Triangulation of GRB 150127B
  83. GRB 150120A: Gemini-N imaging and host redshift
  84. GRB 150127A: Fermi-LAT detection
  85. Swift Trigger 628458 likely not astrophysical
  86. GRB 150123A: Swift/UVOT observations
  87. GRB 150120B: Mondy optical observations
  88. Konus-Wind observation of GRB 150118B
  89. GRB 150120B: RATIR Optical and NIR Observations
  90. IPN Triangulation of GRB 150118B (long/intense)
  91. GRB 150120A: ISON-NM early optical limit
  92. GRB 150120B: Swift/UVOT Upper Limits
  93. GRB 150120B: GROND Afterglow Detection
  94. GRB 150101B: Confirmation of a fading optical counterpart
  95. GRB 150120B: MITSuME Okayama upper limits
  96. Konus-Wind observation of GRB 150118C
  97. GRB 150101B/Swift J123205.1-105602: TNG NIR follow-up
  98. GRB 150120A: Swift/UVOT Upper Limits
  99. GRB 150101B/Swift J123205.1-105602, deep VLT observations
  100. GRB 150120B: Enhanced Swift-XRT position

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