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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"

11762 results found.

  1. Fermi trigger No 723412808: Global MASTER-Net observations report
  2. GRB 231204A: Fermi GBM Final Real-time Localization
  3. GRB 231203A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  4. Konus-Wind detection of GRB 231129C
  5. Fermi trigger No 723149952: Global MASTER-Net observations report
  6. GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
  7. GRB 231129C: Fermi-LAT detection
  8. GRB 231129C: GECAM-B detection of a bright burst
  9. GRB 231129C: AstroSat CZTI detection
  10. GRB 231127A: GRBAlpha detection
  11. GRB 231129C: MAXI/GSC detection
  12. Fermi trigger No 722977823: Global MASTER-Net observations report
  13. GRB 231129B: MAXI/GSC detection
  14. Fermi-LAT gamma-ray observations of IceCube-231125A
  15. GRB 231129A: GECAM-C detection of a long burst
  16. GRB 231129A: INTEGRAL detection of a long GRB
  17. GRB 231127A: AstroSat CZTI detection
  18. GRB 231123B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  19. GRB 231124A: GRBAlpha detection
  20. GRB 231125A: AstroSat CZTI detection of a short burst
  21. GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
  22. GRB230506B: VIRT optical upper limit
  23. Fermi trigger No 722462310: Global MASTER-Net observations report
  24. GRB 231115A: XMM-Newton observation
  25. GRB 231123A: AstroSat CZTI detection
  26. GRB 231117A: Mondy optical observations
  27. GRB 231118A: REM optical afterglow detection
  28. GRB 231122B: AstroSat CZTI detection
  29. GRB 231122B: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  30. GRB 231117A: Continued GTC Observations
  31. Fermi trigger No 722349867: Global MASTER-Net observations report
  32. GRB 231122A: GECAM detection
  33. GRB 231122B: GECAM detection
  34. GRB 231118A: ATCA detection of radio counterpart
  35. LIGO/Virgo/KAGRA S231118d: Upper limits from Swift/BAT-GUANO
  36. LIGO/Virgo/KAGRA S231118an: Upper limits from Swift/BAT-GUANO
  37. LIGO/Virgo/KAGRA S231114n: Upper limits from Swift/BAT-GUANO
  38. LIGO/Virgo/KAGRA S231113bb: Upper limits from Swift/BAT-GUANO
  39. Konus-Wind detection of GRB 231020A
  40. GRB 231117A: LDT Confirmation of Optical Fading
  41. 231118A: Swift-UVOT Detection
  42. LIGO/Virgo/KAGRA S231119ab: Coverage and upper limits from MAXI/GSC observations
  43. GRB 231120A: Fermi GBM Final Real-time Localization
  44. GRB 231117A: Swift-XRT refined Analysis
  45. GRB 231118A: Swift-XRT refined Analysis
  46. GRB 231118A: AstroSat CZTI detection
  47. GRB 231118A: LCOGT Optical Observations
  48. GRB 231118A: MASTER OT observation
  49. Swift GRB231118.72: Global MASTER-Net observations report
  50. GRB 231115A: JinShan optical upper limits
  51. Konus-Wind detection of GRB 231117A (short/hard)
  52. GRB 231115A: optical observations from INAF observatories
  53. GRB 231117A: AGILE detection of a bright short burst
  54. GRB 231117A: AstroSat CZTI detection of a bright short burst
  55. GRB 231115A: Non-detection of radio emission with CHIME/FRB
  56. GRB 231111A: Swift/UVOT Detection
  57. GRB 231115A: Swift/BAT-GUANO detection of a short burst
  58. Konus-Wind detection of GRB 231115A (a probable Magnetar Giant Flare from M82)
  59. GRB 231115A: Kinder observations with Lulin observatory
  60. GRB231115A: GRANDMA Observations
  61. LIGO/Virgo S231113bw: upper limits from AGILE/MCAL
  62. LIGO/Virgo/KAGRA S231113cd: Coverage and upper limits from MAXI/GSC observations
  63. LIGO/Virgo/KAGRA S231113bw: Coverage and upper limits from MAXI/GSC observations
  64. LIGO/Virgo/KAGRA S231113bw: Identification of a GW compact binary merger candidate
  65. GRB 231111A: Afterglow redshift from OSIRIS+/GTC
  66. GRB 231110A: AstroSat CZTI detection
  67. GRB 231111A: Leavitt Observatory optical observations
  68. GRB 231111A: Osservatorio Astronomico "Nastro Verde" optical observations with detection of an optical counterpart
  69. GRB 231111A: GECAM-C detection of a long burst (correction)
  70. GRB 231110A: GECAM-B detection (correction)
  71. GRB 231111A: GECAM-C detection of a long burst
  72. GRB 231110A: GECAM detection
  73. GRB 231111A: Swift detection of a burst with an optical counterpart
  74. Swift GRB231111.60: Global MASTER-Net observations report
  75. Swift GRB231110.89: Global MASTER-Net observations report
  76. GRB 231110A: Swift detection of a burst
  77. Fermi GRB 231108A: Global MASTER-Net observations report
  78. Fermi trigger No 721006392: Global MASTER-Net observations report
  79. LIGO/Virgo/KAGRA S231102w: Upper limits from Swift/BAT-GUANO
  80. Fermi GRB 231106A: Global MASTER-Net observations report
  81. Fermi-LAT gamma-ray observations of IceCube-231103A
  82. GRB 231104A: Fermi GBM Observation
  83. Fermi GRB 231103A: Global MASTER-Net observations report
  84. GRB 231104A: AstroSat CZTI detection
  85. GRB 231104A: Fermi-LAT detection
  86. GRB 231104A: Swift/UVOT Upper Limits
  87. Swift GRB231104.07: Global MASTER-Net observations report
  88. Fermi-LAT gamma-ray observations of IceCube-231027A
  89. Fermi trigger No 720498201: Global MASTER-Net observations report
  90. GRB 231030B: GRBAlpha detection
  91. GRB 231030B: Fermi GBM Detection
  92. GRB 231030B: AstroSat CZTI detection
  93. Fermi GRB 231030B: Global MASTER-Net observations report
  94. LIGO/Virgo/KAGRA S231029y: Upper limits from Swift/BAT-GUANO
  95. LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
  96. GRID detection of GRB 231020A
  97. GRB 231028A: AstroSat CZTI detection
  98. Fermi trigger No 720224759: Global MASTER-Net observations report
  99. Swift GRB 231028A: Global MASTER-Net observations report
  100. IceCube Alert 231027.18: Global MASTER-Net observations report

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