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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 160203A: Skynet PROMPT-CTIO observations of the optical afterglow
  2. GRB 160203A: Swift-XRT refined Analysis
  3. GRB 160203A: TAROT La Silla - TAROT Calern - Zadko observations
  4. GRB 160203A: Swift/UVOT Detection
  5. GRB 160203A: Enhanced Swift-XRT position
  6. The bright GRB160203A: X-shooter spectroscopy and redshift
  7. GRB 160203A: LCOGT-Cerro Tololo optical afterglow confirmation
  8. GRB 160203A: GROND Afterglow Candidate
  9. GRB 160203A: Swift detection of a burst
  10. GRB 160131A: correction to VLA position
  11. GRB 160131A: VLA detection
  12. GRB160131A: NOEMA detection of the millimetre afterglow
  13. Fermi GBM trigger 475675010/160128498 is not a GRB
  14. Konus-Wind observation of GRB 160131A
  15. GRB 160131A: Optical observations from T150 OSN
  16. GRB 160131A: AbAO optical observations
  17. GRB 160131A: Mondy optical observations
  18. GRB 160131A Swift/UVOT Detection
  19. GRB 160131A: Xinglong/BFOSC spectroscopy
  20. GRB 160131A: MITSuME Ishigakijima Optical Observation
  21. GRB 160131A: GROND Detection of the Optical/NIR Afterglow
  22. GRB 160131A: GTC spectroscopy of the afterglow
  23. GRB 160131A: TNG spectroscopic observations and redshift
  24. GRB 160131A: Bassano Bresciano Observatory optical observations
  25. GRB 160131A: Swift-XRT refined Analysis
  26. GRB 160131A: Khureltogot optical observations
  27. GRB 160131A: TNG optical observations
  28. GRB 160131A: iTelescope optical observations
  29. GRB 160131A: Swift-BAT refined analysis
  30. GRB 160131A: Enhanced Swift-XRT position
  31. GRB 160131A: LCOGT-SSO optical observations
  32. GRB 160131A: RATIR Optical Observations
  33. GRB 160131A: Xinglong 60cm WFT optical observation
  34. GRB160131A: Xinglong TNT optical observation
  35. GRB 160131A: LCOGT-FTN optical afterglow observations
  36. GRB160131.35 MASTER-Net OT detection
  37. GRB 160131A: Swift detection of a burst with an optical counterpart
  38. GRB 160127A: RATIR Optical Observations
  39. GRB 160127A: Khureltogot optical observations
  40. GRB 160127A: MITSuME Akeno optical upper limits
  41. GRB 160127A: VLA Detection
  42. GRB 160127A: LCOGT-Sutherland optical upper limit
  43. GRB 160127A: Swift/UVOT Detection
  44. GRB 160127A: Swift-BAT refined analysis
  45. GRB 160127A: Swift-XRT refined Analysis
  46. GRB 160123A: TAROT La Silla observatory optical observations
  47. GRB 160127A: RATIR Optical Observations
  48. GRB 160127A: Enhanced Swift-XRT position
  49. GRB 160127A: TAROT La Silla observatory optical light curve
  50. GRB 160127A: Swift detection of a burst with an optical counterpart
  51. LIGO Virgo G211117: MWA Observations
  52. GRB 160123A: GROND Upper limits
  53. GRB 160121A: RATIR Optical Observations
  54. GRB 160118A CALET Gamma-Ray Burst Monitor detection
  55. GRB 160121A: TSHAO optical observation
  56. GRB 160123A: NOT J-band observations
  57. GRB 160123A: Swift/UVOT Upper Limits
  58. GRB 160123A: Swift-XRT refined Analysis
  59. GRB 160123A: Swift-BAT refined analysis
  60. GRB 160123A: LCOGT-SSO optical upper limit
  61. GRB 160123A: Enhanced Swift-XRT position
  62. GRB 160123A: Swift detection of a burst
  63. GRB 160121A: redshift from the 10.4m GTC
  64. GRB 160121A: RATIR Optical Observations
  65. GRB 160121A: Swift-XRT refined Analysis
  66. GRB 160121A: Swift/UVOT Upper Limits
  67. GRB 160121A: GROND Afterglow observations
  68. GRB 160121A: TSHAO optical afterglow confirmation
  69. GRB 160121A: Swift-BAT refined analysis
  70. GRB 160121A: Enhanced Swift-XRT position
  71. GRB 160121A: 1.8m MOA optical afterglow detection
  72. GRB 160117B: RATIR continued observations
  73. GRB 160117B: TNG spectroscopy and redshift confirmation
  74. LIGO/VIRGO G184098: Summary of VLA results for iPTF15cyk
  75. GRB 160121A: MASTER-Amur observations
  76. GRB 160121A: Swift detection of a burst
  77. Konus-Wind observation of GRB 160119A
  78. GRB 160117A: Swift-XRT afterglow detection
  79. GRB 160119A: VLA Detection
  80. GRB 160117B: VLA Detection
  81. GRB 160117B: further RATIR observations
  82. GRB 160119A: afterglow confirmation from the NOT
  83. GRB160119A: BOOTES-2/TELMA Early Upper Limits
  84. GRB 160119A: Swift/UVOT Upper Limits
  85. LIGO/Virgo G184098: MASTER final result
  86. GRB 160119A: GROND optical/NIR afterglow observations
  87. GRB 160119A: RATIR Optical and NIR Observations
  88. GRB 160117B: RATIR Optical and NIR Observations
  89. GRB 160119A: Swift-BAT refined analysis
  90. GRB 160117B: further NOT optical observations of the afterglow
  91. GRB 160119A: Swift-XRT refined Analysis
  92. GRB 160119A: Enhanced Swift-XRT position
  93. GRB 160119A: NOT and GTC afterglow candidate
  94. GRB 160117B: Early iTelescope observation
  95. GRB 160119A: Swift detection of a burst
  96. GRB 160117A: Swift/UVOT Upper Limits
  97. GRB 151228B: AbAO optical upper limit
  98. GRB 160104A: ISON-Ussuriysk optical observations
  99. LIGO/Virgo G211117: Refined localization from CBC parameter estimation
  100. GRB 160117A: Swift-XRT observations

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