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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 160131A: Khureltogot optical observations
  2. GRB 160131A: TNG optical observations
  3. GRB 160131A: iTelescope optical observations
  4. GRB 160131A: Swift-BAT refined analysis
  5. GRB 160131A: Enhanced Swift-XRT position
  6. GRB 160131A: LCOGT-SSO optical observations
  7. GRB 160131A: RATIR Optical Observations
  8. GRB 160131A: Xinglong 60cm WFT optical observation
  9. GRB160131A: Xinglong TNT optical observation
  10. GRB 160131A: LCOGT-FTN optical afterglow observations
  11. GRB160131.35 MASTER-Net OT detection
  12. GRB 160131A: Swift detection of a burst with an optical counterpart
  13. GRB 160127A: RATIR Optical Observations
  14. GRB 160127A: Khureltogot optical observations
  15. GRB 160127A: MITSuME Akeno optical upper limits
  16. GRB 160127A: VLA Detection
  17. GRB 160127A: LCOGT-Sutherland optical upper limit
  18. GRB 160127A: Swift/UVOT Detection
  19. GRB 160127A: Swift-BAT refined analysis
  20. GRB 160127A: Swift-XRT refined Analysis
  21. GRB 160123A: TAROT La Silla observatory optical observations
  22. GRB 160127A: RATIR Optical Observations
  23. GRB 160127A: Enhanced Swift-XRT position
  24. GRB 160127A: TAROT La Silla observatory optical light curve
  25. GRB 160127A: Swift detection of a burst with an optical counterpart
  26. LIGO Virgo G211117: MWA Observations
  27. GRB 160123A: GROND Upper limits
  28. GRB 160121A: RATIR Optical Observations
  29. GRB 160118A CALET Gamma-Ray Burst Monitor detection
  30. GRB 160121A: TSHAO optical observation
  31. GRB 160123A: NOT J-band observations
  32. GRB 160123A: Swift/UVOT Upper Limits
  33. GRB 160123A: Swift-XRT refined Analysis
  34. GRB 160123A: Swift-BAT refined analysis
  35. GRB 160123A: LCOGT-SSO optical upper limit
  36. GRB 160123A: Enhanced Swift-XRT position
  37. GRB 160123A: Swift detection of a burst
  38. GRB 160121A: redshift from the 10.4m GTC
  39. GRB 160121A: RATIR Optical Observations
  40. GRB 160121A: Swift-XRT refined Analysis
  41. GRB 160121A: Swift/UVOT Upper Limits
  42. GRB 160121A: GROND Afterglow observations
  43. GRB 160121A: TSHAO optical afterglow confirmation
  44. GRB 160121A: Swift-BAT refined analysis
  45. GRB 160121A: Enhanced Swift-XRT position
  46. GRB 160121A: 1.8m MOA optical afterglow detection
  47. GRB 160117B: RATIR continued observations
  48. GRB 160117B: TNG spectroscopy and redshift confirmation
  49. LIGO/VIRGO G184098: Summary of VLA results for iPTF15cyk
  50. GRB 160121A: MASTER-Amur observations
  51. GRB 160121A: Swift detection of a burst
  52. Konus-Wind observation of GRB 160119A
  53. GRB 160117A: Swift-XRT afterglow detection
  54. GRB 160119A: VLA Detection
  55. GRB 160117B: VLA Detection
  56. GRB 160117B: further RATIR observations
  57. GRB 160119A: afterglow confirmation from the NOT
  58. GRB160119A: BOOTES-2/TELMA Early Upper Limits
  59. GRB 160119A: Swift/UVOT Upper Limits
  60. LIGO/Virgo G184098: MASTER final result
  61. GRB 160119A: GROND optical/NIR afterglow observations
  62. GRB 160119A: RATIR Optical and NIR Observations
  63. GRB 160117B: RATIR Optical and NIR Observations
  64. GRB 160119A: Swift-BAT refined analysis
  65. GRB 160117B: further NOT optical observations of the afterglow
  66. GRB 160119A: Swift-XRT refined Analysis
  67. GRB 160119A: Enhanced Swift-XRT position
  68. GRB 160119A: NOT and GTC afterglow candidate
  69. GRB 160117B: Early iTelescope observation
  70. GRB 160119A: Swift detection of a burst
  71. GRB 160117A: Swift/UVOT Upper Limits
  72. GRB 151228B: AbAO optical upper limit
  73. GRB 160104A: ISON-Ussuriysk optical observations
  74. LIGO/Virgo G211117: Refined localization from CBC parameter estimation
  75. GRB 160117A: Swift-XRT observations
  76. GRB 160117B: GROND optical/NIR afterglow observations
  77. GRB 160117B: VLT/X-shooter spectroscopy
  78. GRB 160117B: iTelescope T17 optical observations
  79. GRB 160117B: NOT optical afterglow observations
  80. GRB 160117B: Swift-XRT refined Analysis
  81. GRB 160117A: Swift-BAT refined analysis
  82. GRB 160117B: Swift/UVOT Detection
  83. GRB 160117B: Enhanced Swift-XRT position
  84. GRB 160117B: LCOGT-SSO optical observations
  85. GRB 160117B: MASTER-Amur OT observations
  86. Konus-Wind observation of GRB 160113A
  87. GRB 160117B: Swift detection of a burst with optical counterpart
  88. GRB 160117A: Swift detection of a burst
  89. LIGO/Virgo G211117: Preliminary VLA observation summary of PS15dpn
  90. GRB 160106A: CALET Gamma-Ray Burst Monitor detection
  91. IPN Triangulation of GRB 160113A
  92. LIGO/Virgo G211117: Further Swift-XRT sources
  93. Konus-Wind observation of GRB 160104B
  94. LIGO/Virgo G211117: INAF NOT follow-up of PanStarrs candidates
  95. Konus-Wind observation of GRB 160102A
  96. Konus-Wind observation of GRB 151231A
  97. Konus-Wind observation of GRB 160111A
  98. IPN Triangulation of GRB 160111A (short/hard)
  99. GRB 151225A: Correction to the trigger time of GCN 18724
  100. GRB 160113A: Swift-XRT observations

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