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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"

7421 results found.

  1. Fermi/LAT search for counterpart to the IceCube event 67093193 (run 127853)
  2. GRB 160422A: XRT Afterglow Confirmation
  3. LSGT observation of GRB 160425A
  4. GRB 160422A: Swift/UVOT Afterglow Confirmation
  5. GRB 160425A: Swift detection of an unusual burst with an optical afterglow
  6. LIGO/Virgo G197392 / LVT151012: Identification of a GW CBC Candidate
  7. GRB 160424A: Swift/UVOT Upper Limit
  8. GRB 160422A: Swift-XRT afterglow detection
  9. GRB 160422A: Swift/UVOT Candidate Afterglow
  10. GRB 160422A: Swift ToO observations
  11. GRB 160417A: Swift detection of a burst with an optical counterpart
  12. GRB 160411A - Gemini-S afterglow candidate
  13. GRB 160410A: further NOT optical observations
  14. GRB 160412A: Swift detection of a burst
  15. GRB 160409A: Swift ToO observations
  16. GRB 160410A: Swift detection of a (possibly-short) burst with an optical counterpart
  17. GRB 160408A: Swift detection of a short burst
  18. GRB 160401A: Swift ToO observations
  19. GRB 160327A: Swift detection of a burst
  20. GRB 160325A: afterglow confirmation
  21. GRB160325A Swift/UVOT Detection
  22. GRB 160325A: Swift detection of a burst
  23. Swift detects GX 301-2 in very high state
  24. GRB 160321A: Swift detection of a probable burst
  25. Swift detection of a likely new SGR: SGR 0755-2933
  26. GRB 160314A: Optical observations from OSN
  27. GRB 160228A: GROND afterglow confirmation and X-shooter host candidate redshift
  28. GRB 160314A: Swift detection of a burst
  29. GRB 160313A: Swift detection of a burst
  30. GRB 160310A: Swift ToO observations
  31. LIGO/Virgo G211117: HAWC follow-up of northern sky
  32. Trigger 677981: Swift detection of IGRJ17091-3624
  33. Swift trigger 677890 is noise
  34. GRB 160303A: GROND Optical Detection
  35. GRB 160303A: VLT/FORS2 afterglow obervations
  36. GRB 160303A: Optical observations from the NOT
  37. Swift possibly triggered on IGR17091-3624
  38. GRB 160303A: Swift detection of a burst, possibly short
  39. GRB 160228A: Swift/UVOT Upper Limits
  40. GRB 160228A: Mondy optcial observations
  41. GRB 160228A: RATIR Optical and NIR Observations
  42. GRB 160228A: GROND Afterglow Candidate
  43. GRB 160228A: Swift detection of a burst
  44. GRB 160227A: Swift detection of a burst with an optical counterpart
  45. GRB 160225A: LOAO optical upper limit
  46. GRB 160225A: Continued RATIR Optical and NIR Observations
  47. GRB 160225A: RATIR Optical and NIR Observations
  48. GRB 160225A: Swift detection of a burst
  49. GRB 160223A: Swift-XRT afterglow detection
  50. GRB 160223A: AbAO optical observations
  51. GRB 160223B: LCOGT-FTN optical observations
  52. GRB 160223B: Swift ToO observations
  53. GRB 160221A: Swift ToO observations
  54. GRB 160216A: Swift detection of a burst
  55. Swift Trigger 672897 is probably not an astrophysical event
  56. GRB 160206B: iPTF P48 Observations and Optical Transient Candidates
  57. GRB 160206A: Tiled Swift observations
  58. GRB 160203A: GROND Afterglow Candidate
  59. GRB 160203A: Swift detection of a burst
  60. GRB 160131A: Swift detection of a burst with an optical counterpart
  61. GRB 160127A: TAROT La Silla observatory optical light curve
  62. GRB 160127A: Swift detection of a burst with an optical counterpart
  63. GRB 160123A: Swift detection of a burst
  64. GRB 160121A: Swift detection of a burst
  65. GRB 160119A: afterglow confirmation from the NOT
  66. GRB 160119A: NOT and GTC afterglow candidate
  67. GRB 160117B: Early iTelescope observation
  68. GRB 160119A: Swift detection of a burst
  69. LIGO/Virgo G211117: Refined localization from CBC parameter estimation
  70. GRB 160117B: Swift detection of a burst with optical counterpart
  71. IPN Triangulation of GRB 160113A
  72. GRB 160113A: Swift-XRT observations
  73. GRB 160113A: Swift ToO observations
  74. GRB 160113A: iPTF P48 Observations and Optical Transient Candidates
  75. LIGO/Virgo G184098: Refined localizations from CBC parameter estimation
  76. LIGO/Virgo G211117: Updated FAR estimate based on offline re-analysis
  77. LIGO/Virgo G184098: Updated FAR estimate
  78. LIGO/Virgo G211117: Distance estimate from GW data compared to redshift of PS15dpn
  79. LIGO/Virgo G211117: iPTF Observations of PS15dpn
  80. LIGO/Virgo G211117: INAF TNG follow-up of Kanata telescope candidate
  81. GRB 160104A: LCOGT-FTN afterglow candidate
  82. GRB 160104A: Swift detection of a burst
  83. LIGO/Virgo G211117: Fermi/LAT observations
  84. GRB 160102A: Tiled Swift observations
  85. GRB 160101A: Tiled Swift observations
  86. LIGO/Virgo G211117: FLOYDS Classification of SMTJ13331687-1607330 as a Two-Week-Old Type Ia Supernova
  87. LIGO/Virgo G211117: LBT follow-up imaging of iPTF15fhq
  88. LIGO/Virgo G211117: 44 transients from Pan-STARRS data during 2015-12-28/30
  89. LIGO/Virgo G211117: LBT Follow-up of iPTF15fen
  90. Trigger 668879: Swift detection of V 404 Cyg again
  91. Trigger 668877: Swift detection of V 404 Cyg
  92. LIGO/Virgo G211117: SkyMapper observations and transient candidate
  93. LIGO/Virgo G211117: iPTF Optical Transient Candidates
  94. GRB 151229A: Swift detection of a short burst
  95. LIGO/Virgo G211117: Fermi GBM Observations
  96. GRB 151228B: Swift detection of a burst with an optical detection
  97. LIGO/Virgo G211117: Identification of a GW CBC Candidate
  98. LIGO/Virgo G184098: Fermi-LAT search for high-energy gamma-ray counterpart
  99. GRB151215A: P60 Optical Afterglow Candidate
  100. GRB 151215A: Swift detection of a burst

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