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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"

19613 results found.

  1. GRB 251115A: Fermi-LAT detection
  2. GRB 251112A: Swift-BAT refined analysis
  3. LIGO/Virgo/KAGRA S251112cm: Swift XRT observations, 20 X-ray sources
  4. GRB 251112A: Swift/UVOT Upper Limits
  5. GRB 251112A: Swift-XRT refined Analysis
  6. Swift Trigger 1413695: a possible GRB 251112A
  7. GRB251111A: 1.3m DFOT optical upper limit
  8. GRB 251111A: Swift-XRT afterglow detection
  9. GRB 251111A: Swift-XRT observations
  10. GRB 251013C: Chandra X-ray observations and jet break detection
  11. GRB 251103B: Swift-BAT refined analysis
  12. GRB 251106A: Swift/UVOT Upper Limits
  13. GRB 251105A: AstroSat CZTI detection
  14. GRB 251106A: Swift-XRT afterglow detection
  15. GRB 251106A: Kilonova-Catcher optical upper limit
  16. GRB 251106A: Swift/BAT arcminute localization of a burst
  17. GRB 251103B: AstroSat CZTI detection
  18. GRB 250920C: TERI Gamma-ray detection
  19. GRB 251105A: Fermi GBM Observation
  20. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  21. GRB 251103B: Swift/UVOT Upper Limits
  22. GRB 251103B: Fermi GBM observation
  23. GRB 251103A: WFST optical observations
  24. GRB 251103B: Nanshan/HMT optical upper limit
  25. GRB 251103A: Swift/BAT-GUANO arcminute localization of a burst
  26. GRB 251103B: MITSuME Akeno optical upper limits
  27. GRB 251103B: Swift-XRT refined Analysis
  28. Swift GRB 251103B: Global MASTER-Net observations report
  29. GRB 251103B: GROWTH-India Telescope optical upper limits
  30. GRB 251103A: Kilonova-Catcher optical afterglow detection
  31. GRB 251103B: Enhanced Swift-XRT position
  32. GRB 251103B: Prompt enhanced Swift-XRT position
  33. GRB 251103B: Swift detection of a burst
  34. GRB 251103A: Swift/UVOT Detection
  35. GRB 251103A: Swift-XRT afterglow detection
  36. GRB 251031A: Fermi GBM Observation
  37. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  38. GRB 251022A: Swift-XRT confirmation of fading
  39. GRB 250925A: VZLUSAT-2 detection
  40. GRB 251028B: Fermi/GBM observation
  41. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  42. GRB251025B: 3.6m DOT Optical Observations
  43. GRB 251025B: Swift-XRT confirmation of fading
  44. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  45. GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
  46. GRB 251023B: Swift-UVOT Upper Limits
  47. GRB 251027A: Swift-XRT observations
  48. GRB 251022A: SVOM/GRM observation
  49. GRB 251026B: Swift ToO observations
  50. GRB 251017A: Mondy AZT-33IK and Koshka Zeiss-1000 optical observations
  51. GRB 251017A: INASAN-Kislovodsk optical observations
  52. GRB 251025B: Kilonova-Catcher optical afterglow detection
  53. GRB 251025C: AstroSat CZTI detection
  54. GRB 251026A: Swift-XRT observations
  55. GRB 251025B: SVOM/VT optical bump
  56. GRB 251025B: ULL-ASTRO-MASTER optical counterpart detection with IAC80 telescope at Teide Observatory
  57. GRB 251024A: Swift/UVOT Upper Limits
  58. GRB 251025B: Swift-XRT afterglow detection
  59. GRB 251024A: Swift-BAT refined analysis
  60. GRB 251024A: Swift-XRT refined Analysis
  61. GRB 251003A: VLA Detection
  62. GRB 251024A: Enhanced Swift-XRT position
  63. GRB 251023C: Glowbug gamma-ray detection
  64. GRB 251024A: LCOGT Optical Afterglow Detection
  65. GRB 251024A: Swift detection of a burst
  66. Swift GRB 251024A: Global MASTER-Net observations report
  67. GRB 251023C: AstroSat CZTI detection
  68. GRB 251022A: Swift-XRT detection of GOTO25iym
  69. GRB 251023C: CALET Gamma-Ray Burst Monitor detection
  70. GRB 251023C: Swift/BAT-GUANO localization skymap of a burst
  71. GRB 251022A: Fermi GBM Observation
  72. GRB 251022A: Swift/BAT-GUANO localization skymap of a burst
  73. IPN triangulation of GRB 251016B
  74. EP#01709247298: Swift-XRT counterpart detection
  75. GRB 251022A: MASTER OT detection
  76. GRB 251022A: Fermi-LAT detection
  77. GRB 251022A: Tiled Swift observations
  78. GRB 250911A: MAXI/GSC detection
  79. GRB 251017A: COLIBRÍ optical observations of a late plateau
  80. GRB 251017A: Swift-BAT refined analysis
  81. GRB 251018A: Fermi GBM Observation
  82. GRB 251018A: BOOTES-5 and BOOTES-7 early optical detections
  83. GRB 251018A: Swift-XRT refined Analysis
  84. GRB 251018A: Enhanced Swift-XRT position
  85. GRB 251016A: Swift-XRT afterglow detection
  86. GRB 251017A: Swift/UVOT Detection
  87. GRB 251016A: Swift/UVOT Detection
  88. GRB 251018A: Swift/UVOT Detection
  89. GRB 251016A: VLT/FORS2 Optical Observation
  90. GRB 251017A: COLIBRÍ photometric redshift
  91. GRB 251017A: Swift-XRT refined Analysis
  92. GRB 251018A: MASTER OT detection
  93. GRB 251018A: TRT optical afterglow detection
  94. Swift GRB 251018A: Global MASTER-Net observations report
  95. GRB 251018A: Swift detection of a burst with an optical counterpart
  96. GRB 251017A: SVOM/VT optical observation
  97. GRB 251011A: Fermi GBM Observation
  98. GRB 251017A: Glowbug gamma-ray detection
  99. GRB 251017A: JinShan observations of the optical afterglow
  100. Swift GRB 251017A: Global MASTER-Net observations report

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