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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 160216A: Enhanced Swift-XRT position
  2. GRB 160216A: Swift detection of a burst
  3. LIGO/Virgo G184098: MAXI/GSC search for an X-ray counterpart of GW150914
  4. Fermi GBM trigger 477254668/160215781 is not a GRB
  5. GRB160131A: detection of polarisation by Astrosat CZTI
  6. GRB 160131A: second epoch observations with the GMRT
  7. Low frequency GMRT observations of GRB 160131A
  8. GRB 160206A: Kiso/KWFC optical observations
  9. GRB 160203A: RATIR Upper Limits
  10. GRB 160206B: Fermi GBM detection
  11. LIGO/Virgo G211117: LOFAR follow-up
  12. GRB 160131A: TSHAO optical observations
  13. GRB 160203A: MITSuME Akeno optical upper limits
  14. Swift Trigger 672897 is probably not an astrophysical event
  15. GRB 151215A: TAROT Calern observatory very early optical detection
  16. GRB 160206A: Swift/UVOT observations
  17. GRB 160203A: Zadko observatory - Gingin optical detection
  18. GRB 160203A: Swift-BAT refined analysis
  19. GRB 160206A: GROND Observations
  20. GRB 160206A: Swift-XRT observations
  21. GRB 160206B: iPTF P48 Observations and Optical Transient Candidates
  22. GRB 160206A: Tiled Swift observations
  23. GRB 160206A: MAXI/GSC detection
  24. GRB 160131A: TSHAO optical observations
  25. GRB 160131A: Mondy optcial observations
  26. GRB 160203A: TSHAO optical observations
  27. GRB 160203A: RATIR Optical Observations
  28. GRB 160131A: RATIR Optical Observations
  29. GRB 160203A: Skynet PROMPT-CTIO observations of the optical afterglow
  30. GRB 160203A: Swift-XRT refined Analysis
  31. GRB 160203A: TAROT La Silla - TAROT Calern - Zadko observations
  32. GRB 160203A: Swift/UVOT Detection
  33. GRB 160203A: Enhanced Swift-XRT position
  34. The bright GRB160203A: X-shooter spectroscopy and redshift
  35. GRB 160203A: LCOGT-Cerro Tololo optical afterglow confirmation
  36. GRB 160203A: GROND Afterglow Candidate
  37. GRB 160203A: Swift detection of a burst
  38. GRB 160131A: correction to VLA position
  39. GRB 160131A: VLA detection
  40. GRB160131A: NOEMA detection of the millimetre afterglow
  41. Fermi GBM trigger 475675010/160128498 is not a GRB
  42. Konus-Wind observation of GRB 160131A
  43. GRB 160131A: Optical observations from T150 OSN
  44. GRB 160131A: AbAO optical observations
  45. GRB 160131A: Mondy optical observations
  46. GRB 160131A Swift/UVOT Detection
  47. GRB 160131A: Xinglong/BFOSC spectroscopy
  48. GRB 160131A: MITSuME Ishigakijima Optical Observation
  49. GRB 160131A: GROND Detection of the Optical/NIR Afterglow
  50. GRB 160131A: GTC spectroscopy of the afterglow
  51. GRB 160131A: TNG spectroscopic observations and redshift
  52. GRB 160131A: Bassano Bresciano Observatory optical observations
  53. GRB 160131A: Swift-XRT refined Analysis
  54. GRB 160131A: Khureltogot optical observations
  55. GRB 160131A: TNG optical observations
  56. GRB 160131A: iTelescope optical observations
  57. GRB 160131A: Swift-BAT refined analysis
  58. GRB 160131A: Enhanced Swift-XRT position
  59. GRB 160131A: LCOGT-SSO optical observations
  60. GRB 160131A: RATIR Optical Observations
  61. GRB 160131A: Xinglong 60cm WFT optical observation
  62. GRB160131A: Xinglong TNT optical observation
  63. GRB 160131A: LCOGT-FTN optical afterglow observations
  64. GRB160131.35 MASTER-Net OT detection
  65. GRB 160131A: Swift detection of a burst with an optical counterpart
  66. GRB 160127A: RATIR Optical Observations
  67. GRB 160127A: Khureltogot optical observations
  68. GRB 160127A: MITSuME Akeno optical upper limits
  69. GRB 160127A: VLA Detection
  70. GRB 160127A: LCOGT-Sutherland optical upper limit
  71. GRB 160127A: Swift/UVOT Detection
  72. GRB 160127A: Swift-BAT refined analysis
  73. GRB 160127A: Swift-XRT refined Analysis
  74. GRB 160123A: TAROT La Silla observatory optical observations
  75. GRB 160127A: RATIR Optical Observations
  76. GRB 160127A: Enhanced Swift-XRT position
  77. GRB 160127A: TAROT La Silla observatory optical light curve
  78. GRB 160127A: Swift detection of a burst with an optical counterpart
  79. LIGO Virgo G211117: MWA Observations
  80. GRB 160123A: GROND Upper limits
  81. GRB 160121A: RATIR Optical Observations
  82. GRB 160118A CALET Gamma-Ray Burst Monitor detection
  83. GRB 160121A: TSHAO optical observation
  84. GRB 160123A: NOT J-band observations
  85. GRB 160123A: Swift/UVOT Upper Limits
  86. GRB 160123A: Swift-XRT refined Analysis
  87. GRB 160123A: Swift-BAT refined analysis
  88. GRB 160123A: LCOGT-SSO optical upper limit
  89. GRB 160123A: Enhanced Swift-XRT position
  90. GRB 160123A: Swift detection of a burst
  91. GRB 160121A: redshift from the 10.4m GTC
  92. GRB 160121A: RATIR Optical Observations
  93. GRB 160121A: Swift-XRT refined Analysis
  94. GRB 160121A: Swift/UVOT Upper Limits
  95. GRB 160121A: GROND Afterglow observations
  96. GRB 160121A: TSHAO optical afterglow confirmation
  97. GRB 160121A: Swift-BAT refined analysis
  98. GRB 160121A: Enhanced Swift-XRT position
  99. GRB 160121A: 1.8m MOA optical afterglow detection
  100. GRB 160117B: RATIR continued observations

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