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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

37708 results found.

  1. GRB 250213A: Swift ToO observations
  2. GRB 250214A: Fermi GBM Final Real-time Localization
  3. GRB 250213A: SVOM detection of a burst
  4. GRB 250205A: VIRT Optical Upper Limit
  5. GRB 250205A: Leavitt Observatory optical upper limit
  6. GRB 250210A: GRBAlpha detection
  7. Fermi GRB 250212A: Global MASTER-Net observations report
  8. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  9. Fermi trigger No 760945500: Global MASTER-Net observations report
  10. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  11. GRB 250211B: A long GRB detected by INTEGRAL
  12. GRB 250211A: Swift ToO observations
  13. GRB 250212A: Fermi GBM Final Real-time Localization
  14. GRB 250207A: Fermi GBM Observation
  15. GRB 250206A: Fermi GBM Observation
  16. GRB 250205A / EP250205A: radio detection with the VLA
  17. Konus-Wind detection of GRB 250207A
  18. Konus-Wind detection of GRB 250206A
  19. GRB 250210A: SVOM/GRM observation of a long burst
  20. Fermi Gamma-ray Burst Monitor trigger 760945500/250211240 is not a GRB
  21. GRB 250207A: Skynet optical afterglow observations
  22. GRB 241128A: VIRT Optical Upper Limit
  23. EP250207A: Upper limits from Fermi-GBM Observations
  24. GRB 250210A: INTEGRAL SPI-ACS detection
  25. GRB 250210A: AstroSat CZTI detection
  26. GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
  27. Fermi GRB 250210A: Global MASTER-Net observations report
  28. GRB 250210A: Fermi GBM Final Real-time Localization
  29. LIGO/Virgo/KAGRA S250206dm: Upper limits from GECAM Observations
  30. GRB 250204B: GRBAlpha detection
  31. GRB 250204A: GRBAlpha detection
  32. Fermi-LAT Gamma-ray Observations of IceCube-250207A
  33. GRB 250207A: 1.3m DFOT Optical observations
  34. GRB 250206A: Swift-XRT observations
  35. GRB 250129A: GRANDMA Continued Afterglow Detection
  36. GRB 250207A: Swift-BAT refined analysis
  37. GRB 250205A: 1.3m DFOT optical upper limit
  38. GRB 250206A: Tiled Swift observations
  39. GRB 250206A: EIRSAT-1 GMOD Detection
  40. GRB 250206A: Fermi-LAT detection
  41. GRB 250207B: Swift-XRT observations
  42. GRB 250208A: Fermi GBM Final Real-time Localization
  43. GRB 250207A: Swift-XRT refined Analysis
  44. GRB 250207A: Enhanced Swift-XRT position
  45. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  46. GRB 250207A: REM IR afterglow detection
  47. GRB 250207A: FRAM-Auger optical detection
  48. GRB 250207B: Tiled Swift observations
  49. Konus-Wind detection of GRB 250204B
  50. IceCube-250207A - IceCube observation of a high-energy neutrino candidate track-like event
  51. GRB 250207A: REM optical afterglow detection
  52. GRB 250207A: Swift/UVOT Detection
  53. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  54. GRB 250129A: Continued AbAO and Mondy optical observations
  55. GRB 250207B: MAXI/GSC detection
  56. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  57. LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
  58. GRB 250207A: Swift detection of a burst with optical counterpart
  59. GRB 250207A: Fermi GBM Final Real-time Localization
  60. Fermi-LAT Gamma-ray Observations of IceCube-250203A
  61. GRB 250206A: BALROG localization (Fermi Trigger 760564296 / GRB 250206827)
  62. GRB 250206A: Fermi GBM Final Real-time Localization
  63. GRB 250205A: Fermi GBM Observation
  64. GRB 250205A: REM NIR upper limit
  65. EP250205a/GRB 250205A: FTW optical and NIR observations of the counterpart
  66. GRB 250205A: Swift/UVOT Upper Limits
  67. EP250205a/GRB 250205A: correction to the source localization
  68. EP250205a/GRB 250205A: Einstein Probe observation
  69. GRB 250127C: SVOM/GRM observation of a burst
  70. GRB 250204B: SVOM/GRM observation of a likely short burst
  71. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  72. GRB 250205A: Swift/XRT detection
  73. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  74. GRB250205A: SVOM/VT optical afterglow detection
  75. GRB 250205A: GOTO optical upper limits
  76. GRB 250205A: OHP/T193 optical counterpart candidate
  77. GRB 250205A: Liverpool Telescope optical counterpart candidate detection
  78. GRB 250205A: SVOM detection of a burst
  79. Konus-Wind detection of GRB 250201A
  80. IPN triangulation of GRB 250201A
  81. Konus-Wind detection of GRB 250202B
  82. GRB 250129A: Swift-BAT refined analysis
  83. EP 250108A: Upper limits from Fermi-GBM Observations
  84. IPN triangulation of GRB 250204B (short/hard)
  85. IPN triangulation of GRB 250202B
  86. GRB 250204B: AstroSat CZTI detection of a short burst
  87. GRB 250204B: Fermi GBM Final Localization
  88. GRB 250129A: LCO late afterglow detection
  89. GRB 250129A: AbAO AS-32 and Mondy AZT-33IK optical observations
  90. GRB 250204A: Fermi GBM Final Real-time Localization
  91. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  92. GRB 250202B: NuSTAR detection of the prompt emission
  93. GRB 250202C: GRBAlpha detection
  94. GRB 250202B: Fermi GBM Detection
  95. IceCube-250203A - IceCube observation of a high-energy neutrino candidate track-like event
  96. GRB 250129a: Liverpool Telescope optical follow-up
  97. GRB 240129A: further SAO RAS optical observations
  98. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  99. GRB 250202C: Fermi GBM Final Real-time Localization
  100. GRB 250129A: SVOM/C-GFT optical observations

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