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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"

7301 results found.

  1. GRB160325A Swift/UVOT Detection
  2. GRB 160325A: Swift detection of a burst
  3. Swift detects GX 301-2 in very high state
  4. GRB 160321A: Swift detection of a probable burst
  5. Swift detection of a likely new SGR: SGR 0755-2933
  6. GRB 160314A: Optical observations from OSN
  7. GRB 160228A: GROND afterglow confirmation and X-shooter host candidate redshift
  8. GRB 160314A: Swift detection of a burst
  9. GRB 160313A: Swift detection of a burst
  10. GRB 160310A: Swift ToO observations
  11. LIGO/Virgo G211117: HAWC follow-up of northern sky
  12. Trigger 677981: Swift detection of IGRJ17091-3624
  13. Swift trigger 677890 is noise
  14. GRB 160303A: GROND Optical Detection
  15. GRB 160303A: VLT/FORS2 afterglow obervations
  16. GRB 160303A: Optical observations from the NOT
  17. Swift possibly triggered on IGR17091-3624
  18. GRB 160303A: Swift detection of a burst, possibly short
  19. GRB 160228A: Swift/UVOT Upper Limits
  20. GRB 160228A: Mondy optcial observations
  21. GRB 160228A: RATIR Optical and NIR Observations
  22. GRB 160228A: GROND Afterglow Candidate
  23. GRB 160228A: Swift detection of a burst
  24. GRB 160227A: Swift detection of a burst with an optical counterpart
  25. GRB 160225A: LOAO optical upper limit
  26. GRB 160225A: Continued RATIR Optical and NIR Observations
  27. GRB 160225A: RATIR Optical and NIR Observations
  28. GRB 160225A: Swift detection of a burst
  29. GRB 160223A: Swift-XRT afterglow detection
  30. GRB 160223A: AbAO optical observations
  31. GRB 160223B: LCOGT-FTN optical observations
  32. GRB 160223B: Swift ToO observations
  33. GRB 160221A: Swift ToO observations
  34. GRB 160216A: Swift detection of a burst
  35. Swift Trigger 672897 is probably not an astrophysical event
  36. GRB 160206B: iPTF P48 Observations and Optical Transient Candidates
  37. GRB 160206A: Tiled Swift observations
  38. GRB 160203A: GROND Afterglow Candidate
  39. GRB 160203A: Swift detection of a burst
  40. GRB 160131A: Swift detection of a burst with an optical counterpart
  41. GRB 160127A: TAROT La Silla observatory optical light curve
  42. GRB 160127A: Swift detection of a burst with an optical counterpart
  43. GRB 160123A: Swift detection of a burst
  44. GRB 160121A: Swift detection of a burst
  45. GRB 160119A: afterglow confirmation from the NOT
  46. GRB 160119A: NOT and GTC afterglow candidate
  47. GRB 160117B: Early iTelescope observation
  48. GRB 160119A: Swift detection of a burst
  49. LIGO/Virgo G211117: Refined localization from CBC parameter estimation
  50. GRB 160117B: Swift detection of a burst with optical counterpart
  51. IPN Triangulation of GRB 160113A
  52. GRB 160113A: Swift-XRT observations
  53. GRB 160113A: Swift ToO observations
  54. GRB 160113A: iPTF P48 Observations and Optical Transient Candidates
  55. LIGO/Virgo G184098: Refined localizations from CBC parameter estimation
  56. LIGO/Virgo G211117: Updated FAR estimate based on offline re-analysis
  57. LIGO/Virgo G184098: Updated FAR estimate
  58. LIGO/Virgo G211117: Distance estimate from GW data compared to redshift of PS15dpn
  59. LIGO/Virgo G211117: iPTF Observations of PS15dpn
  60. LIGO/Virgo G211117: INAF TNG follow-up of Kanata telescope candidate
  61. GRB 160104A: LCOGT-FTN afterglow candidate
  62. GRB 160104A: Swift detection of a burst
  63. LIGO/Virgo G211117: Fermi/LAT observations
  64. GRB 160102A: Tiled Swift observations
  65. GRB 160101A: Tiled Swift observations
  66. LIGO/Virgo G211117: FLOYDS Classification of SMTJ13331687-1607330 as a Two-Week-Old Type Ia Supernova
  67. LIGO/Virgo G211117: LBT follow-up imaging of iPTF15fhq
  68. LIGO/Virgo G211117: 44 transients from Pan-STARRS data during 2015-12-28/30
  69. LIGO/Virgo G211117: LBT Follow-up of iPTF15fen
  70. Trigger 668879: Swift detection of V 404 Cyg again
  71. Trigger 668877: Swift detection of V 404 Cyg
  72. LIGO/Virgo G211117: SkyMapper observations and transient candidate
  73. LIGO/Virgo G211117: iPTF Optical Transient Candidates
  74. GRB 151229A: Swift detection of a short burst
  75. LIGO/Virgo G211117: Fermi GBM Observations
  76. GRB 151228B: Swift detection of a burst with an optical detection
  77. LIGO/Virgo G211117: Identification of a GW CBC Candidate
  78. LIGO/Virgo G184098: Fermi-LAT search for high-energy gamma-ray counterpart
  79. GRB151215A: P60 Optical Afterglow Candidate
  80. GRB 151215A: Swift detection of a burst
  81. GRB 151212A: GROND Optical Afterglow Candidate
  82. GRB 151212A: Tiled Swift observations
  83. GRB 151210A: Optical afterglow candidate from LCOGT-Cerro Tololo
  84. GRB 151210A: Swift detection of a burst
  85. GRB 151205C: Tiled Swift observations
  86. GRB151205B: Initial UVOT observations
  87. GRB 151205A: Swift detection of a burst
  88. GRB 151127A: Swift detection of a short burst
  89. GRB 151122A: Swift ToO observations
  90. Swift Trigger 664610: is unlikely a GRB
  91. LIGO/Virgo G194575: Updated significance from offline GW analysis
  92. GRB 151120A: Swift ToO observations
  93. LIGO/Virgo G194575: Fermi GBM Observations
  94. GRB 151118A: Swift detection of a burst
  95. GRB 151114A: GROND Detection of the Optical/NIR Afterglow Candidate
  96. GRB 151114A: Swift detection of a burst with an optical counterpart
  97. GRB 151112A: GROND Detection of the Optical/NIR Afterglow Candidate
  98. GRB 151112A: initial UVOT observations
  99. GRB 151111A: GROND marginal detection of a afterglow candidate
  100. GRB 151111A: LCOGT-FTS afterglow observations

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