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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"

2857 results found.

  1. Fermi GRB 231108A: Global MASTER-Net observations report
  2. GRB 231106A: AstroSat CZTI detection
  3. Fermi GRB 231103A: Global MASTER-Net observations report
  4. GRB 231104A: AstroSat CZTI detection
  5. GRB 231030B: AstroSat CZTI detection
  6. GRB 231028A: AstroSat CZTI detection
  7. Fermi trigger No 720224759: Global MASTER-Net observations report
  8. GRB 231028A: Swift detection of a burst
  9. IceCube Alert 231027.18: Global MASTER-Net observations report
  10. LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
  11. LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
  12. GRB 231024A: LCOGT and ZTF detections of the GOTO optical counterpart candidate
  13. GRB 231020A: AstroSat CZTI detection
  14. GRB 231020B: AstroSat CZTI detection
  15. Fermi GRB 231020A: Global MASTER-Net observations report
  16. GRB 231019A: Fermi GBM Final Real-time Localization
  17. GRB 231015A: AstroSat CZTI detection
  18. GRB 231018A: Fermi GBM Final Real-time Localization
  19. GRB 231012A: Fermi GBM Final Real-time Localization
  20. AT2023sva / GRB230916B: GIT observations of the afterglow
  21. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  22. IPN triangulation of GRB 230919A (short)
  23. GRB 230919A: AstroSat CZTI detection
  24. GRB 230915A: Fermi GBM observation
  25. GRB 230917A: AstroSat CZTI detection
  26. Fermi trigger No 716449174: Global MASTER-Net observations report
  27. IceCube Alert 230914.22: Global MASTER-Net observations report
  28. Fermi trigger No 716419312: Global MASTER-Net observations report
  29. GRB 230911B: AstroSat CZTI detection
  30. Fermi trigger No 716145795: Global MASTER-Net observations report
  31. GRB 230911C: GOTO optical upper limits
  32. GRB 230906A: BlackGEM upper limits
  33. GRB 230906A: AstroSat CZTI detection
  34. LIGO/Virgo/KAGRA S230908b: one counterpart neutrino candidate from IceCube neutrino searches
  35. GRB 230908A: AstroSat CZTI detection
  36. GRB 230905B: AstroSat CZTI detection
  37. Fermi GRB 230903A: Global MASTER-Net observations report
  38. Integral GRB230902.00: Global MASTER-Net observations report
  39. GRB 230828A: AstroSat CZTI detection
  40. Fermi GRB 230827A: Global MASTER-Net observations report
  41. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  42. Fermi trigger No 714618399: Global MASTER-Net observations report
  43. GRB 230824B: AstroSat CZTI detection
  44. GRB 230818B: AstroSat CZTI detection
  45. GRB 230820A: AstroSat CZTI detection
  46. GRB 230818A: further SAO RAS Zeiss-1000 observations
  47. GRB 230818A: AstroSat CZTI detection
  48. GRB 230818A: KGO RC-25 optical observations
  49. Fermi GRB 230818A: Global MASTER-Net observations report
  50. Swift GRB230818.98: Global MASTER-Net observations report
  51. Swift GRB230818.98: Global MASTER-Net OT detection
  52. GRB 230817A: AstroSat CZTI detection
  53. GRB 230815B: AstroSat CZTI detection
  54. GRB 230812B: Iota Scorpii Observatory, La Spezia, Italy
  55. GRB 230812B: KAIT Optical Afterglow Candidate
  56. LAT GRB230812.79: Global MASTER-Net observations report
  57. GRB 230805B: AstroSat CZTI detection
  58. Fermi trigger No 713136868: Global MASTER-Net observations report
  59. GRB 230805B : MITSuME Akeno optical upper limits
  60. transient SPT-SVJ025406.5-702837: ATCA follow-up observations
  61. Fermi GRB 230807A: Global MASTER-Net observations report
  62. Fermi trigger No 713134237: Global MASTER-Net observations report
  63. Fermi trigger No 712927418: Global MASTER-Net observations report
  64. LIGO/Virgo/KAGRA S230805x: Identification of a GW compact binary merger candidate
  65. GRB 230802B: AstroSat CZTI detection
  66. GRB 230803A: AstroSat CZTI detection
  67. Fermi trigger No 712713532: Global MASTER-Net observations report
  68. Fermi trigger No 712306969: Global MASTER-Net observations report
  69. GRB 230727A: AstroSat CZTI detection
  70. Swift GRB230728.12: Global MASTER-Net observations report
  71. Fermi trigger No 712143685: Global MASTER-Net observations report
  72. GRB 230727A: Fermi GBM Final Real-time Localization
  73. Integral GRB230726.26: Global MASTER-Net observations report
  74. Integral GRB230725.99: Global MASTER-Net observations report
  75. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  76. GRB 230723B: Fermi GBM observation
  77. Fermi trigger No 711805358: Global MASTER-Net observations report
  78. Swift GRB 230723B: Global MASTER-Net observations report
  79. GRB 230723B: Swift detection of a burst
  80. Swift GRB230720.30: Global MASTER-Net observations report
  81. IPN triangulation of GRB 230712C (short)
  82. Fermi GRB 230713A: Global MASTER-Net observations report
  83. GRB 230709C: AstroSat CZTI detection
  84. Fermi GRB 230707A: Global MASTER-Net observations report
  85. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  86. Fermi trigger No 710117592: Global MASTER-Net observations report
  87. GRB 230701B: AstroSat CZTI detection
  88. LIGO/Virgo/KAGRA S230627c: observations of ZTF23aaptsuy/AT2023lx in AbAO observatory
  89. GRB 230625B: AstroSat CZTI detection
  90. Fermi GRB 230628D: Global MASTER-Net observations report
  91. LIGO/Virgo S230622e: Global MASTER-Net observations report
  92. LIGO/Virgo S230621ad: Global MASTER-Net observations report
  93. Fermi trigger No 709083929: Global MASTER-Net observations report
  94. LIGO/Virgo S230620ad: Global MASTER-Net observations report
  95. LIGO/Virgo S230620au: Global MASTER-Net observations report
  96. IPN triangulation of GRB 230616A (short)
  97. LIGO/Virgo S230616aa: Global MASTER-Net observations report
  98. LIGO/Virgo S230615ak: Global MASTER-Net observations report
  99. LIGO/Virgo S230618k: Global MASTER-Net observations report
  100. LIGO/Virgo S230617bc: Global MASTER-Net observations report

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