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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"

5401 results found.

  1. GRB 231117A: AGILE detection of a bright short burst
  2. GRB 231117A: AstroSat CZTI detection of a bright short burst
  3. GRB 231117A: Swift detection of a bright short burst
  4. GRB231115A: Liverpool Telescope imaging
  5. GRB 231115A: archival HST observations
  6. Fermi GRB 231115A: Global MASTER-Net observations report
  7. GRB 231111A: GMG observation (correction)
  8. GRB 231111A: GMG observation upper limit
  9. LIGO/Virgo/KAGRA S231110g: Identification of a GW compact binary merger candidate
  10. IceCube-231103A: No candidates from the Zwicky Transient Facility
  11. Fermi trigger No 721204446: Global MASTER-Net observations report
  12. Fermi GRB 231108A: Global MASTER-Net observations report
  13. GRB 231108A: Fermi GBM Final Real-time Localization
  14. Fermi GRB 231106A: Global MASTER-Net observations report
  15. IceCube-231103A: Upper limits from a search for additional neutrino events in IceCube
  16. Fermi-LAT gamma-ray observations of IceCube-231103A
  17. Fermi GRB 231103A: Global MASTER-Net observations report
  18. GRB231104A: LCOGT Optical Upper Limits
  19. IceCube Alert 231103.39: Global MASTER-Net observations report
  20. IceCube-231103A - IceCube observation of a high-energy neutrino candidate track-like event
  21. GRB 231024A: GRANDMA observations of AT2023vuc/GOTO23baj candidate
  22. Fermi trigger No 720498201: Global MASTER-Net observations report
  23. Fermi GRB 231030B: Global MASTER-Net observations report
  24. LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
  25. Fermi trigger No 720224759: Global MASTER-Net observations report
  26. IceCube Alert 231027.18: Global MASTER-Net observations report
  27. LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
  28. LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
  29. LIGO/Virgo/KAGRA S231025a: two counterpart neutrino candidates from IceCube neutrino searches
  30. IceCube-231004A: Upper limits from a search for additional neutrino events in IceCube
  31. IceCube-231004A: No significant detection in HAWC
  32. GRB 231003A is not a GRB
  33. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  34. LIGO/Virgo/KAGRA S230922g: Identification of a GW compact binary merger candidate
  35. Fermi GBM Statement for Trigger 716527670/230916144
  36. AT2023sva: redshift from OSIRIS+/GTC of the ZTF afterglow
  37. ZTF and SEDM Observations of the Candidate Optical Afterglow AT 2023sva
  38. GRB 230911A: Fermi GBM Observation
  39. Swift GRB230916.13: Global MASTER-Net observations report
  40. GRB 230911A: Swift-XRT afterglow detection
  41. Fermi trigger No 716449174: Global MASTER-Net observations report
  42. GRB 230911A: GOTO optical counterpart candidate
  43. IPN triangulation of GRB 230911D (long)
  44. GRB 230911A: Fermi GBM Final Real-time Localization
  45. GRB 230910A: Fermi GBM Final Real-time Localization
  46. LIGO/Virgo/KAGRA S230908b: one counterpart neutrino candidate from IceCube neutrino searches
  47. GRB 230205A: LBT spectroscopy of two host galaxy candidates
  48. Fermi GRB 230906A: Global MASTER-Net observations report
  49. Fermi trigger No 715429986: Global MASTER-Net observations report
  50. Swift GRB230903.72: Global MASTER-Net observations report
  51. Fermi GRB 230827A: Global MASTER-Net observations report
  52. Trigger 1187142: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  53. Fermi trigger No 714618399: Global MASTER-Net observations report
  54. LIGO/Virgo/KAGRA S230824r: Identification of a GW compact binary merger candidate
  55. LIGO/Virgo/KAGRA S230822bm: Identification of a GW compact binary merger candidate
  56. GRB 230815A: ATCA detection of radio counterpart
  57. GRB 230818A: Tautenburg observations
  58. GRB 230818A: Bassano Bresciano Observatory optical observations
  59. GRB 230818A: KGO RC-25 optical observations
  60. GRB 230818A: Swift/UVOT Detection
  61. GRB 230818A: SAO RAS Zeiss-1000 observations
  62. Fermi GRB 230818A: Global MASTER-Net observations report
  63. GRB 230817A: AstroSat CZTI detection
  64. GRB 230815A: VLT/HAWK-I near-infrared afterglow detection
  65. GRB 230815A: SOAR/Goodman follow-up imaging
  66. GRB 230815A: Swift-BAT refined analysis
  67. GRB 230815A: Enhanced Swift-XRT position
  68. GRB 230815A: Swift detection of a burst
  69. GRB 230812B: further SAO RAS optical observations
  70. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  71. LAT GRB230812.79: Global MASTER-Net observations report
  72. Fermi GRB 230812B: Global MASTER-Net observations report
  73. LIGO/Virgo/KAGRA S230811n: Identification of a GW compact binary merger candidate
  74. Fermi trigger No 713136868: Global MASTER-Net observations report
  75. Fermi trigger No 713205976: Global MASTER-Net observations report
  76. LIGO/Virgo/KAGRA S230808i: Identification of a GW unmodeled transient candidate
  77. Fermi trigger No 712927418: Global MASTER-Net observations report
  78. LIGO/Virgo/KAGRA S230805x: Identification of a GW compact binary merger candidate
  79. Fermi trigger No 712798043: Global MASTER-Net observations report
  80. GRB 230803A: AstroSat CZTI detection
  81. Fermi trigger No 712718833: Global MASTER-Net observations report
  82. Fermi trigger No 712713532: Global MASTER-Net observations report
  83. Fermi trigger No 712651827: Global MASTER-Net observations report
  84. Swift GRB 230802A: Global MASTER-Net observations report
  85. LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
  86. GRB 230728A: LCOGT Optical Upper Limit
  87. GRB 230727A: AstroSat CZTI detection
  88. GRB 230728A: Swift detection of a burst
  89. GRB 230727A: Swift/BAT-GUANO detection of a burst
  90. GRB 230727A: Fermi GBM Final Real-time Localization
  91. IBAS trigger number 10337: not a real GRB
  92. IPN triangulation of GRB 230723A (short)
  93. IceCube Alert 230724.08: Global MASTER-Net observations report
  94. Fermi trigger No 711805358: Global MASTER-Net observations report
  95. GRB 230703A detected with multiple GRID detectors
  96. GRB 230707A: Fermi GBM Detection
  97. Fermi GRB 230707A: Global MASTER-Net observations report
  98. GRB 230707A: Fermi GBM Final Real-time Localization
  99. LVK S230619bd/GBM-230619: Upper limits from a two-week IceCube neutrino search
  100. LIGO/Virgo/KAGRA S230627c: GRANDMA observations of galaxies and ZTF counterpart candidates

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