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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"

21572 results found.

  1. Swift GRB230311.83: Global MASTER-Net observations report
  2. Swift GRB230311.81: Global MASTER-Net observations report
  3. GRB 230307A: SOAR/Goodman detection of the possible host galaxy
  4. Swift GRB230311.84: Global MASTER-Net observations report
  5. Swift GRB230311.82: Global MASTER-Net observations report
  6. Triggers 1159434, 1159435 and 1159437: Swift detection of Sco X-1 due to Star Tracker loss of lock
  7. Alert from the HAWC Burst Monitor HAWC-230311A
  8. TESS Detection of the Optical Afterglow of GRB230307A
  9. Trigger 1159327: Swift detection of SGR1806-20
  10. GRB 230307A: GECKO optical observations and detections of the afterglow
  11. GRB 230307A: Gemini-South Confirmation of the Optical Afterglow
  12. Fermi GRB 230310A: Global MASTER-Net observations report
  13. GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
  14. GRB 230307A: Erratum of the GCN 33441
  15. GRB 230204B: MASTER detection of an object near NTT Optical Afterglow Candidate
  16. GRB 230307A: Possible optical afterglow
  17. GRB 230228A: NUTTelA-TAO / BSTI Optical Limits
  18. GRB 230217A: ATCA rapid-response radio detection
  19. GRB 230307A: Swift/BAT upper limits on the early afterglow
  20. GRB 230307A: Swift-XRT observations
  21. Fermi GRB 230307A: Global MASTER-Net observations report
  22. Konus-Wind detection of GRB 230307A
  23. Fermi GRB 230308A: Global MASTER-Net observations report
  24. GRB 230307A: Tiled Swift observations
  25. Fermi-LAT gamma-ray observations of IceCube-230306A
  26. GRB 230307A: GECAM detection of an extremely bright burst
  27. Fermi trigger No 699811746: Global MASTER-Net observations report
  28. IceCube Alert 230306.46: Global MASTER-Net observations report
  29. GRB 230228A: 6 GHz VLA radio upper limit
  30. GRB 230228A: Swift/UVOT Upper Limits
  31. Fermi GRB 230301B: Global MASTER-Net observations report
  32. Fermi trigger No 699294715: Global MASTER-Net observations report
  33. Fermi trigger No 699311646: Global MASTER-Net observations report
  34. GRB 230228A: Mondy optical upper limit
  35. Fermi GRB 230227A: Global MASTER-Net observations report
  36. Fermi trigger No 699029364: Global MASTER-Net observations report
  37. GRB 230217A: VLT/FORS2 optical observations and candidate counterpart
  38. GRB 230216A Mondy Observations
  39. GRB 230205A: VLA radio afterglow confirmation
  40. GRB 230217A: Swift/UVOT Upper Limits
  41. GRB 230216A: Swift/UVOT Upper Limits
  42. GRB 230217A: Continued Gemini Observations
  43. GRB 230217A: Swift-XRT afterglow detection
  44. Fermi-LAT gamma-ray observations of IceCube-230220A
  45. Fermi GRB 230220B: Global MASTER-Net observations report
  46. GRB 230217A: Gemini South optical upper limits
  47. GRB 230217A: 6 GHz VLA observations
  48. GRB 230217A: Gemini-South Optical Observation
  49. IceCube-230217A: BOOTES-4/MET Optical Observations
  50. Fermi-LAT gamma-ray observations of IceCube-230217A
  51. GRB 230217A: Swift-XRT observations
  52. Fermi trigger No 698427992: Global MASTER-Net observations report
  53. IceCube Alert 230217.87: Global MASTER-Net observations report
  54. GRB 230205A: Lowell Discovery Telescope Observations
  55. GRB 230204B: Lowell Discovery Telescope Observations
  56. Swift GRB 230216A: Global MASTER-Net observations report
  57. GRB 230216A: Zadko observatory - Gingin optical observations
  58. Fermi GRB 230215A: Global MASTER-Net observations report
  59. GRB 230204B: ATCA radio detection
  60. Fermi trigger No 697926015: Global MASTER-Net observations report
  61. Fermi trigger No 697904388: Global MASTER-Net observations report
  62. GRB 230209B: Swift/BAT-GUANO detection outside the coded FOV
  63. Fermi trigger No 697678542: Global MASTER-Net observations report
  64. Fermi GRB 230209B: Global MASTER-Net observations report
  65. GRB 230205A: 6 GHz VLA observations
  66. GRB 221009A: Continued Swift Observations
  67. GRB 230205A: possible host galaxy detection with the Schmidt - Asiago telescope
  68. GRB 230204B: MASTER early OT detection
  69. GRB 230207B: Swift/BAT-GUANO detection outside the coded FOV
  70. ZTF23aabmzlp/AT2023azs: Neil Gehrels Swift Observatory X-ray observations
  71. Fermi GRB 230207A: Global MASTER-Net observations report
  72. GRB 230204B: Swift/UVOT Upper Limits
  73. Fermi trigger No 697403223: Global MASTER-Net observations report
  74. Fermi trigger No 697396830: Global MASTER-Net observations report
  75. GRB 230205A: Swift/UVOT Upper Limits
  76. GRB 230204B: Swift-XRT afterglow detection
  77. GRB 230205A: OHP/T193 optical observations
  78. GRB 230204B: VLT/X-shooter redshift
  79. GRB 230204B: ATLAS detection of the optical afterglow and a projected location in a nearby galaxy group
  80. GRB 230204B: Swift ToO observations
  81. GRB 230204B: Detection by GRBAlpha
  82. GRB 230204B: GIT discovery of the likely optical afterglow
  83. GRB 230204B: Swift/BAT-GUANO detection outside the coded FOV
  84. GRB 230204A: Swift/UVOT Upper Limits
  85. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  86. Fermi trigger No 697208885: Global MASTER-Net observations report
  87. GRB 230204A: Swift detection of a possible burst (or possible transient Swift J1552.8-5055)
  88. Fermi trigger No 697098930: Global MASTER-Net observations report
  89. ZTF23aabmzlp/AT2023azs: Lulin 1m LOT optical observations
  90. ZTF23aabmzlp/AT2023azs: VLA radio detection
  91. ZTF23aaarlti/AT2023avj: AMI-LA radio detection
  92. ZTF23aabmzlp/AT2023azs: AMI-LA radio upper limit
  93. IceCube Alert 230201.26: Global MASTER-Net observations report
  94. Fermi GRB 230201B: Global MASTER-Net observations report
  95. Fermi-LAT gamma-ray observations of IceCube-230201A
  96. Fermi GRB 230201A: Global MASTER-Net observations report
  97. GRB 221009A: radio afterglow detection with the EVN
  98. ZTF23aabmzlp/AT2023azs: LCOGT Optical Detection
  99. ZTF23aaarlti/AT2023avj: Assy continued optical observations
  100. ZTF23aabmzlp/AT2023azs: Mondy and AbAO optical observations

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