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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 160220A: Fermi GBM observation
  2. GRB 160220A: Enhanced Swift-XRT position
  3. GRB 160220A: Swift-XRT observations
  4. GRB 160220A: Swift detection of a burst
  5. LIGO/Virgo GW150914: BOOTES-3 simultaneous imaging
  6. LIGO/Virgo G184098: MASTER arhival results
  7. GRB 160216A: Swift-BAT refined analysis
  8. Konus-Wind observation of GRB 160216A (and GRB 160216B)
  9. GRB 160216A: Swift-XRT refined Analysis
  10. LIGO/Virgo G184098: Correction for GCN Circular 18361
  11. GRB 160216A: Swift/UVOT Upper Limits
  12. GRB 160216A: Enhanced Swift-XRT position
  13. GRB 160216A: Swift detection of a burst
  14. LIGO/Virgo G184098: MAXI/GSC search for an X-ray counterpart of GW150914
  15. Fermi GBM trigger 477254668/160215781 is not a GRB
  16. GRB160131A: detection of polarisation by Astrosat CZTI
  17. GRB 160131A: second epoch observations with the GMRT
  18. Low frequency GMRT observations of GRB 160131A
  19. GRB 160206A: Kiso/KWFC optical observations
  20. GRB 160203A: RATIR Upper Limits
  21. GRB 160206B: Fermi GBM detection
  22. LIGO/Virgo G211117: LOFAR follow-up
  23. GRB 160131A: TSHAO optical observations
  24. GRB 160203A: MITSuME Akeno optical upper limits
  25. Swift Trigger 672897 is probably not an astrophysical event
  26. GRB 151215A: TAROT Calern observatory very early optical detection
  27. GRB 160206A: Swift/UVOT observations
  28. GRB 160203A: Zadko observatory - Gingin optical detection
  29. GRB 160203A: Swift-BAT refined analysis
  30. GRB 160206A: GROND Observations
  31. GRB 160206A: Swift-XRT observations
  32. GRB 160206B: iPTF P48 Observations and Optical Transient Candidates
  33. GRB 160206A: Tiled Swift observations
  34. GRB 160206A: MAXI/GSC detection
  35. GRB 160131A: TSHAO optical observations
  36. GRB 160131A: Mondy optcial observations
  37. GRB 160203A: TSHAO optical observations
  38. GRB 160203A: RATIR Optical Observations
  39. GRB 160131A: RATIR Optical Observations
  40. GRB 160203A: Skynet PROMPT-CTIO observations of the optical afterglow
  41. GRB 160203A: Swift-XRT refined Analysis
  42. GRB 160203A: TAROT La Silla - TAROT Calern - Zadko observations
  43. GRB 160203A: Swift/UVOT Detection
  44. GRB 160203A: Enhanced Swift-XRT position
  45. The bright GRB160203A: X-shooter spectroscopy and redshift
  46. GRB 160203A: LCOGT-Cerro Tololo optical afterglow confirmation
  47. GRB 160203A: GROND Afterglow Candidate
  48. GRB 160203A: Swift detection of a burst
  49. GRB 160131A: correction to VLA position
  50. GRB 160131A: VLA detection
  51. GRB160131A: NOEMA detection of the millimetre afterglow
  52. Fermi GBM trigger 475675010/160128498 is not a GRB
  53. Konus-Wind observation of GRB 160131A
  54. GRB 160131A: Optical observations from T150 OSN
  55. GRB 160131A: AbAO optical observations
  56. GRB 160131A: Mondy optical observations
  57. GRB 160131A Swift/UVOT Detection
  58. GRB 160131A: Xinglong/BFOSC spectroscopy
  59. GRB 160131A: MITSuME Ishigakijima Optical Observation
  60. GRB 160131A: GROND Detection of the Optical/NIR Afterglow
  61. GRB 160131A: GTC spectroscopy of the afterglow
  62. GRB 160131A: TNG spectroscopic observations and redshift
  63. GRB 160131A: Bassano Bresciano Observatory optical observations
  64. GRB 160131A: Swift-XRT refined Analysis
  65. GRB 160131A: Khureltogot optical observations
  66. GRB 160131A: TNG optical observations
  67. GRB 160131A: iTelescope optical observations
  68. GRB 160131A: Swift-BAT refined analysis
  69. GRB 160131A: Enhanced Swift-XRT position
  70. GRB 160131A: LCOGT-SSO optical observations
  71. GRB 160131A: RATIR Optical Observations
  72. GRB 160131A: Xinglong 60cm WFT optical observation
  73. GRB160131A: Xinglong TNT optical observation
  74. GRB 160131A: LCOGT-FTN optical afterglow observations
  75. GRB160131.35 MASTER-Net OT detection
  76. GRB 160131A: Swift detection of a burst with an optical counterpart
  77. GRB 160127A: RATIR Optical Observations
  78. GRB 160127A: Khureltogot optical observations
  79. GRB 160127A: MITSuME Akeno optical upper limits
  80. GRB 160127A: VLA Detection
  81. GRB 160127A: LCOGT-Sutherland optical upper limit
  82. GRB 160127A: Swift/UVOT Detection
  83. GRB 160127A: Swift-BAT refined analysis
  84. GRB 160127A: Swift-XRT refined Analysis
  85. GRB 160123A: TAROT La Silla observatory optical observations
  86. GRB 160127A: RATIR Optical Observations
  87. GRB 160127A: Enhanced Swift-XRT position
  88. GRB 160127A: TAROT La Silla observatory optical light curve
  89. GRB 160127A: Swift detection of a burst with an optical counterpart
  90. LIGO Virgo G211117: MWA Observations
  91. GRB 160123A: GROND Upper limits
  92. GRB 160121A: RATIR Optical Observations
  93. GRB 160118A CALET Gamma-Ray Burst Monitor detection
  94. GRB 160121A: TSHAO optical observation
  95. GRB 160123A: NOT J-band observations
  96. GRB 160123A: Swift/UVOT Upper Limits
  97. GRB 160123A: Swift-XRT refined Analysis
  98. GRB 160123A: Swift-BAT refined analysis
  99. GRB 160123A: LCOGT-SSO optical upper limit
  100. GRB 160123A: Enhanced Swift-XRT position

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