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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"

4046 results found.

  1. GRB 231129C: BALROG localization (Fermi Trigger / GRB 231129799)
  2. GRB 231129C: Fermi GBM detection of a very bright burst
  3. GRB 231129C: Fermi GBM Final Real-time Localization
  4. Fermi trigger No 722977823: Global MASTER-Net observations report
  5. GRB 231129B: MAXI/GSC detection
  6. Integral GRB231129.21: Global MASTER-Net observations report
  7. LIGO/Virgo/KAGRA S231129ac: Identification of a GW compact binary merger candidate
  8. Fermi trigger No 722507896: Global MASTER-Net observations report
  9. Fermi trigger No 722462310: Global MASTER-Net observations report
  10. Fermi trigger No 722349867: Global MASTER-Net observations report
  11. GRB 231117A : MITSuME Akeno optical afterglow candidate detection
  12. GRB 231118A: Fermi GBM Final Real-time Localization
  13. LIGO/Virgo/KAGRA S231118ab: Identification of a GW compact binary merger candidate
  14. GRB 231117A: AKO Optical Upper Limit
  15. Swift GRB 231117A: Global MASTER-Net observations report
  16. GRB 231115A: GBM/Fermi Observations of a probable Giant Flare of Magnetar
  17. GRB 231115A : MITSuME Akeno and Okayama optical upper limits
  18. GRB 231115A: archival HST observations
  19. GECAM-B observation of a short burst from SGR J1555-5402
  20. SGRJ1555-5402: Swift/BAT-GUANO arcminute localization of a SGR flare
  21. GRB 231111A: GMG observation (correction)
  22. GRB 231111A: GMG observation upper limit
  23. Fermi GRB 231108A: Global MASTER-Net observations report
  24. Fermi GRB 231106A: Global MASTER-Net observations report
  25. GRB 231104A: 3.6m DOT optical upper limit
  26. Fermi GRB 231103A: Global MASTER-Net observations report
  27. GRB 231104A: Fermi-LAT detection
  28. LIGO/Virgo/KAGRA S231104ac: Identification of a GW compact binary merger candidate
  29. IceCube Alert 231103.39: Global MASTER-Net observations report
  30. Fermi trigger No 720498201: Global MASTER-Net observations report
  31. GRB 231024A: AKO Optical Counterpart Candidate
  32. Fermi GRB 231030A: Global MASTER-Net observations report
  33. LIGO/Virgo/KAGRA S231029y: One counterpart neutrino candidate from IceCube neutrino searches
  34. LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
  35. LIGO/Virgo/KAGRA S231029y: Identification of a GW compact binary merger candidate
  36. LIGO/Virgo/KAGRA S231029k: Global MASTER-Net observations report
  37. Fermi trigger No 720224759: Global MASTER-Net observations report
  38. LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
  39. LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
  40. IC231004A: GRANDMA observations of AT2023uqf/ZTF23abidzvf candidate
  41. LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
  42. LIGO/Virgo/KAGRA S231020ba: Identification of a GW compact binary merger candidate
  43. Fermi GRB 231019A: Global MASTER-Net observations report
  44. LIGO/Virgo/KAGRA S231014r: Identification of a GW compact binary merger candidate
  45. GRB 230827B: 10.4m GTC spectroscopic redshift
  46. LIGO/Virgo/KAGRA S230927l: Identification of a GW compact binary merger candidate
  47. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  48. IPN triangulation of GRB 230919A (short)
  49. transient AT2023sva: imaging and spectroscopic observations from MISTRAL at Observatoire de Haute-Provence
  50. LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate
  51. LIGO/Virgo/KAGRA S230919bj: Identification of a GW compact binary merger candidate
  52. IceCube-230914A: Upper limits from a search for additional neutrino events in IceCube
  53. GRB 230911A: Swift-XRT afterglow detection
  54. Fermi trigger No 716449174: Global MASTER-Net observations report
  55. IceCube Alert 230914.22: Global MASTER-Net observations report
  56. GRB 230911A: GOTO optical counterpart candidate
  57. GRB 230906A: Chandra detection of the X-ray afterglow
  58. GRB 230903A: VLT/X-shooter optical observations
  59. GRB 230904C: Fermi GBM Final Localization
  60. Fermi GRB 230903A: Global MASTER-Net observations report
  61. GRB 230904B is not a GRB
  62. GRB 230904B: BALROG localization (Fermi Trigger 715526984 / GRB 230904562)
  63. GRB 230828A: AstroSat CZTI detection
  64. GRB 230828A: GRBAlpha detection
  65. Swift Trigger 1188089 is not a GRB
  66. Fermi GRB 230827A: Global MASTER-Net observations report
  67. GRB 230824A: AKO Photometric Follow-up Observations
  68. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  69. GRB 230818B: VZLUSAT-2 detection
  70. LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate
  71. GRB 230818A: SAO RAS Zeiss-1000 observations
  72. Fermi GRB 230818A: Global MASTER-Net observations report
  73. GRB 230818A: Swift detection of a burst
  74. Fermi GRB 230817A: Global MASTER-Net observations report
  75. GRB 230816A: TShAO and Assy optical observations
  76. GRB 230816A: SAO RAS optical observations
  77. IPN triangulation of GRB 230815B
  78. GRB 230812B: Fermi-LAT detection
  79. GRB 230812B: Fermi GBM Observation of a very bright burst
  80. LAT GRB230812.79: Global MASTER-Net observations report
  81. GRB 230812B: Fermi GBM detection of an extremely bright GRB
  82. LIGO/Virgo/KAGRA S230802aq: AstroSat CZTI non-detection and upper limits
  83. IceCube-230724A: JCMT/SCUBA-2 submm observations
  84. LIGO/Virgo/KAGRA S230731an: AstroSat CZTI non-detection and upper limits
  85. LIGO/Virgo/KAGRA S230729z: Identification of a GW compact binary merger candidate
  86. LIGO/Virgo/KAGRA S230726a: Identification of a GW compact binary merger candidate
  87. IceCube Alert 230724.08: Global MASTER-Net observations report
  88. GRB 230724A: Fermi GBM Final Real-time Localization
  89. Fermi trigger No 711805358: Global MASTER-Net observations report
  90. Fermi GRB 230723A: Global MASTER-Net observations report
  91. GRB 230707A: Fermi GBM Detection
  92. Fermi GRB 230707A: Global MASTER-Net observations report
  93. Fermi trigger No 710117592: Global MASTER-Net observations report
  94. GRB 230628E: ATCA rapid radio follow-up
  95. AT2023lcr (ATLAS23msn/ZTF23aaoohpy): ALMA 100 GHz Detection
  96. GRB 230628E - VLT spectroscopic observations
  97. Fermi GRB 230628C: Global MASTER-Net observations report
  98. Fermi GRB 230628D: Global MASTER-Net observations report
  99. GRB 230628E: Swift detection of a burst
  100. GRB 230626A: GRBAlpha detection

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