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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"

8293 results found.

  1. GRB 160228A: GROND afterglow confirmation and X-shooter host candidate redshift
  2. GRB 160314A: Swift detection of a burst
  3. GRB 160313A: Swift detection of a burst
  4. Konus-Wind observation of GRB 160310A (possible ultra-long GRB?)
  5. GRB 160310A: Swift ToO observations
  6. LIGO/Virgo G211117: HAWC follow-up of northern sky
  7. Trigger 677981: Swift detection of IGRJ17091-3624
  8. Swift trigger 677890 is noise
  9. GRB 160303A: GROND Optical Detection
  10. GRB 160303A: VLT/FORS2 afterglow obervations
  11. GRB 160303A: McDonald 2.1m CQUEAN Detection
  12. GRB 160303A: Optical observations from the NOT
  13. Swift possibly triggered on IGR17091-3624
  14. GRB 160303A: Swift detection of a burst, possibly short
  15. GRB 160228A: Swift/UVOT Upper Limits
  16. GRB 160228A: Mondy optcial observations
  17. GRB 160228A: RATIR Optical and NIR Observations
  18. GRB 160228A: GROND Afterglow Candidate
  19. GRB 160228A: Swift detection of a burst
  20. GRB 160227A: Swift detection of a burst with an optical counterpart
  21. GRB 160225A: LOAO optical upper limit
  22. GRB 160225A: Continued RATIR Optical and NIR Observations
  23. GRB 160225A: RATIR Optical and NIR Observations
  24. GRB 160225A: Swift detection of a burst
  25. GRB 160223A: Swift-XRT afterglow detection
  26. GRB 160223A: AbAO optical observations
  27. GRB 160223B: LCOGT-FTN optical observations
  28. GRB 160223B: Swift ToO observations
  29. GRB 160221A: Swift ToO observations
  30. GRB 160216A: Swift detection of a burst
  31. GRB 160206B: Fermi GBM detection
  32. Swift Trigger 672897 is probably not an astrophysical event
  33. GRB 160206B: iPTF P48 Observations and Optical Transient Candidates
  34. GRB 160206A: Tiled Swift observations
  35. GRB 160203A: GROND Afterglow Candidate
  36. GRB 160203A: Swift detection of a burst
  37. Konus-Wind observation of GRB 160131A
  38. GRB 160131A: Swift detection of a burst with an optical counterpart
  39. GRB 160127A: TAROT La Silla observatory optical light curve
  40. GRB 160127A: Swift detection of a burst with an optical counterpart
  41. GRB 160123A: Swift detection of a burst
  42. GRB 160121A: Swift detection of a burst
  43. GRB 160119A: afterglow confirmation from the NOT
  44. GRB 160119A: NOT and GTC afterglow candidate
  45. GRB 160117B: Early iTelescope observation
  46. GRB 160119A: Swift detection of a burst
  47. LIGO/Virgo G211117: Refined localization from CBC parameter estimation
  48. GRB 160117B: Swift detection of a burst with optical counterpart
  49. IPN Triangulation of GRB 160113A
  50. GRB 151225A: Correction to the trigger time of GCN 18724
  51. GRB 160113A: Swift-XRT observations
  52. GRB 160113A: Swift ToO observations
  53. GRB 160113A: iPTF P48 Observations and Optical Transient Candidates
  54. LIGO/Virgo G184098: Refined localizations from CBC parameter estimation
  55. LIGO/Virgo G211117: iPTF Observations of PS15dpn
  56. LIGO/Virgo G211117: Summary of Pan-STARRS transients
  57. LIGO/Virgo G211117: INAF TNG follow-up of Kanata telescope candidate
  58. GRB 160104A: LCOGT-FTN afterglow candidate
  59. GRB 160104A: Swift detection of a burst
  60. LIGO/Virgo G211117: Fermi/LAT observations
  61. LIGO/Virgo G211117: PESSTO classification of Pan-STARRS transients
  62. GRB 160102A: Tiled Swift observations
  63. GRB 160101A: Tiled Swift observations
  64. LIGO/Virgo G211117: FLOYDS Classification of SMTJ13331687-1607330 as a Two-Week-Old Type Ia Supernova
  65. LIGO/Virgo G211117: LBT follow-up imaging of iPTF15fhq
  66. LIGO/Virgo G211117: 44 transients from Pan-STARRS data during 2015-12-28/30
  67. LIGO/Virgo G211117: LBT Follow-up of iPTF15fen
  68. Trigger 668879: Swift detection of V 404 Cyg again
  69. Trigger 668877: Swift detection of V 404 Cyg
  70. LIGO/Virgo G211117: SkyMapper observations and transient candidate
  71. LIGO/Virgo G211117: iPTF Optical Transient Candidates
  72. GRB 151228B: Swift-BAT refined analysis
  73. GRB 151229A: Swift detection of a short burst
  74. LIGO/Virgo G211117: Fermi GBM Observations
  75. GRB 151228B: Swift detection of a burst with an optical detection
  76. LIGO/Virgo G211117: Identification of a GW CBC Candidate
  77. LIGO/Virgo G184098: Fermi-LAT search for high-energy gamma-ray counterpart
  78. GRB151215A: P60 Optical Afterglow Candidate
  79. GRB 151215A: Swift detection of a burst
  80. GRB 151212A: GROND Optical Afterglow Candidate
  81. GRB 151212A: Tiled Swift observations
  82. GRB 151210A: Optical afterglow candidate from LCOGT-Cerro Tololo
  83. GRB 151210A: Swift detection of a burst
  84. GRB 151205C: Tiled Swift observations
  85. GRB151205B: Initial UVOT observations
  86. GRB 151205A: Swift detection of a burst
  87. GRB 151127A: Swift detection of a short burst
  88. GRB 151122A: Swift ToO observations
  89. Swift Trigger 664610: is unlikely a GRB
  90. LIGO/Virgo G194575: Updated significance from offline GW analysis
  91. GRB 151120A: Swift ToO observations
  92. LIGO/Virgo G194575: Fermi GBM Observations
  93. GRB 151118A: Swift detection of a burst
  94. GRB 151114A: GROND Detection of the Optical/NIR Afterglow Candidate
  95. GRB 151114A: Swift detection of a burst with an optical counterpart
  96. GRB 151112A: GROND Detection of the Optical/NIR Afterglow Candidate
  97. GRB 151112A: initial UVOT observations
  98. GRB 151111A: GROND marginal detection of a afterglow candidate
  99. GRB 151111A: Fermi GBM observation
  100. GRB 151111A: LCOGT-FTS afterglow observations

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