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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 160223B: LCOGT-FTN optical observations
  2. GRB 160223B: Fermi GBM observation
  3. GRB 160223B: Swift ToO observations
  4. GRB 160223B: A long GRB detected by INTEGRAL
  5. GRB 160223A: GROND optical/NIR afterglow
  6. GRB 160223A: Swift detection of a burst
  7. GRB 160221A: Fermi GBM observation
  8. LVC GW 150914: TAROT/TZAC Final analysis correction
  9. GRB 160221A: GROND upper limits
  10. Correction to the title of Swift GCN 19051
  11. GRB 160220B: Further GROND Observations
  12. Further Swift/UVOT observations of GRB 160220B
  13. GRB 160221A: Swift-XRT observations
  14. GRB 160221A: MASTER-SAAO early observations
  15. LVC GW 150914: TAROT/TZAC Final analysis
  16. GRB 160221A: Swift ToO observations
  17. GRB 160221A: A long GRB detected by INTEGRAL
  18. Konus-Wind observation of GRB 160220B
  19. Swift trigger 674752 is likely due to a noise fluctuation
  20. GRB 160220B: Swift-BAT refined analysis
  21. GRB 160220B: GROND Observations
  22. GRB 160219A: Fermi GBM detection
  23. GRB 160220A: nIR observations at AAT
  24. GRB 160220A: Swift-XRT refined Analysis
  25. GRB 160220A: Swift-BAT refined analysis
  26. GRB160220B: Swift/UVOT observations
  27. GRB 160220B: Swift-XRT refined Analysis
  28. IPN Triangulation of GRB 160219A (short/hard)
  29. LIGO/Virgo GW150914
  30. GRB160220B: Enhanced Swift-XRT position
  31. GRB160220A: Swift/UVOT observations
  32. Swift Trigger 674752 is likely a noise fluctuation in the direction of IGR17488-3253
  33. GRB 160220A: TAROT Calern and TAROT La Silla observatory optical observations
  34. GRB 160220B: Swift detection of a burst
  35. GRB 160220A: MASTER-Amur observations
  36. GRB 160220A: GROND Optical/NIR Upper Limits
  37. GRB 160220A: Fermi GBM observation
  38. GRB 160220A: Enhanced Swift-XRT position
  39. GRB 160220A: Swift-XRT observations
  40. GRB 160220A: Swift detection of a burst
  41. LIGO/Virgo GW150914: BOOTES-3 simultaneous imaging
  42. LIGO/Virgo G184098: MASTER arhival results
  43. GRB 160216A: Swift-BAT refined analysis
  44. Konus-Wind observation of GRB 160216A (and GRB 160216B)
  45. GRB 160216A: Swift-XRT refined Analysis
  46. LIGO/Virgo G184098: Correction for GCN Circular 18361
  47. GRB 160216A: Swift/UVOT Upper Limits
  48. GRB 160216A: Enhanced Swift-XRT position
  49. GRB 160216A: Swift detection of a burst
  50. LIGO/Virgo G184098: MAXI/GSC search for an X-ray counterpart of GW150914
  51. Fermi GBM trigger 477254668/160215781 is not a GRB
  52. GRB160131A: detection of polarisation by Astrosat CZTI
  53. GRB 160131A: second epoch observations with the GMRT
  54. Low frequency GMRT observations of GRB 160131A
  55. GRB 160206A: Kiso/KWFC optical observations
  56. GRB 160203A: RATIR Upper Limits
  57. GRB 160206B: Fermi GBM detection
  58. LIGO/Virgo G211117: LOFAR follow-up
  59. GRB 160131A: TSHAO optical observations
  60. GRB 160203A: MITSuME Akeno optical upper limits
  61. Swift Trigger 672897 is probably not an astrophysical event
  62. GRB 151215A: TAROT Calern observatory very early optical detection
  63. GRB 160206A: Swift/UVOT observations
  64. GRB 160203A: Zadko observatory - Gingin optical detection
  65. GRB 160203A: Swift-BAT refined analysis
  66. GRB 160206A: GROND Observations
  67. GRB 160206A: Swift-XRT observations
  68. GRB 160206B: iPTF P48 Observations and Optical Transient Candidates
  69. GRB 160206A: Tiled Swift observations
  70. GRB 160206A: MAXI/GSC detection
  71. GRB 160131A: TSHAO optical observations
  72. GRB 160131A: Mondy optcial observations
  73. GRB 160203A: TSHAO optical observations
  74. GRB 160203A: RATIR Optical Observations
  75. GRB 160131A: RATIR Optical Observations
  76. GRB 160203A: Skynet PROMPT-CTIO observations of the optical afterglow
  77. GRB 160203A: Swift-XRT refined Analysis
  78. GRB 160203A: TAROT La Silla - TAROT Calern - Zadko observations
  79. GRB 160203A: Swift/UVOT Detection
  80. GRB 160203A: Enhanced Swift-XRT position
  81. The bright GRB160203A: X-shooter spectroscopy and redshift
  82. GRB 160203A: LCOGT-Cerro Tololo optical afterglow confirmation
  83. GRB 160203A: GROND Afterglow Candidate
  84. GRB 160203A: Swift detection of a burst
  85. GRB 160131A: correction to VLA position
  86. GRB 160131A: VLA detection
  87. GRB160131A: NOEMA detection of the millimetre afterglow
  88. Fermi GBM trigger 475675010/160128498 is not a GRB
  89. Konus-Wind observation of GRB 160131A
  90. GRB 160131A: Optical observations from T150 OSN
  91. GRB 160131A: AbAO optical observations
  92. GRB 160131A: Mondy optical observations
  93. GRB 160131A Swift/UVOT Detection
  94. GRB 160131A: Xinglong/BFOSC spectroscopy
  95. GRB 160131A: MITSuME Ishigakijima Optical Observation
  96. GRB 160131A: GROND Detection of the Optical/NIR Afterglow
  97. GRB 160131A: GTC spectroscopy of the afterglow
  98. GRB 160131A: TNG spectroscopic observations and redshift
  99. GRB 160131A: Bassano Bresciano Observatory optical observations
  100. GRB 160131A: Swift-XRT refined Analysis

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