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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"

3797 results found.

  1. GRB 240214A: Tiled Swift observations
  2. GRB 240214A/1H 0451-560: MAXI/GSC detection
  3. Fermi trigger No 729152364: Global MASTER-Net observations report
  4. Fermi trigger No 729012023: Global MASTER-Net observations report
  5. Konus-Wind detection of GRB 240205B (long / very soft)
  6. GRB 240204A: Swift-BAT refined analysis
  7. Fermi trigger No 728749569: Global MASTER-Net observations report
  8. GRB 240204a: Liverpool Telescope optical afterglow detection
  9. GRB 240128A: Glowbug gamma-ray detection
  10. GRB 240128A: Swift-XRT observations
  11. GRB 240128A: GRBAlpha detection
  12. GRB 240128A: Tiled Swift observations
  13. GRB 240128A: CALET Gamma-Ray Burst Monitor detection
  14. GRB 240128A: MAXI/GSC detection
  15. GRB 240122A: ATCA detection of radio counterpart
  16. GRB240122A: PRIME near infrared detection
  17. IceCube Alert 240123.48: Global MASTER-Net observations report
  18. GRB 240122A: Swift/UVOT Upper Limits
  19. GRB 240122A: BOOTES-2/TELMA optical upper limit and 1.5m OSN detection
  20. GRB 240122A: Swift-XRT afterglow detection
  21. GRB 240122A: VLT/X-shooter redshift confirmation
  22. GRB 240122A: Redshift from OSIRIS+/GTC
  23. GRB 240122A: LT non-detection of GOTO candidate counterpart confirms fading
  24. GRB 240122A: GOTO optical counterpart candidate
  25. GRB 240122A: Tiled Swift observations
  26. GRB 240122A: MAXI/GSC detection
  27. Swift triggers 1209631, 1209632, 1209635 and 1209644 are not interesting astrophysical events
  28. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240118A
  29. Swift Triggers 1209371 through 1209374 are not astrophysical events
  30. GRB 240107A: VZLUSAT-2 detection
  31. Fermi GRB 240115A: Global MASTER-Net observations report
  32. GRB 240114A: MAXI/GSC detection
  33. Fermi GRB 240112D: Global MASTER-Net observations report
  34. Konus-Wind detection of GRB 240101C
  35. GRB 231215A: radio detection with the VLA
  36. Swift GRB240109.17: Global MASTER-Net observations report
  37. GRB 240107A: AstroSat CZTI detection
  38. GRB 240107A: MAXI/GSC detection
  39. IPN triangulation of GRB 240101C (short)
  40. GRB GRB240101C: Fermi GBM observation
  41. GRB 240101C: Swift/BAT-GUANO detection of a short burst
  42. GRB 240101C: AstroSat CZTI detection
  43. GRB 240101C: GRBAlpha detection
  44. GRB 240101C: Fermi GBM Final Localization
  45. Swift GRB240101.85: Global MASTER-Net observations report
  46. Fermi trigger No 725806648: Global MASTER-Net observations report
  47. Fermi trigger No 725592555: Global MASTER-Net observations report
  48. Fermi trigger No 725143760: Global MASTER-Net observations report
  49. Fermi trigger No 724781422: Global MASTER-Net observations report
  50. GRB 231215A: AMI-LA radio detection
  51. GRB 231214A: Swift-BAT refined analysis
  52. GRB 231216A: BOOTES-2/TELMA optical upper limit
  53. GRB 231205B: VZLUSAT-2 detection
  54. GRB 231215A: GAD Observatory, La Spezia, Italy upper limit;
  55. GRB 231215A: Swift/UVOT Detection
  56. GRB 231210B: MeerLICHT afterglow observations
  57. IceCube Alert 231211.03: Global MASTER-Net observations report
  58. Fermi trigger No 723906955: Global MASTER-Net observations report
  59. IPN triangulation of GRB 231129C
  60. IPN triangulation of GRB 231205A
  61. Fermi trigger No 723581802: Global MASTER-Net observations report
  62. GRB 231129C: ASIM MXGS observation and localization
  63. GRB 231205B: Nanshan/HMT optical upper limit
  64. GRB 231205A: DDOTI Upper Limits on the Afterglow
  65. Fermi trigger No 723326169: Global MASTER-Net observations report
  66. LIGO/Virgo/KAGRA S231129ac: Upper limits from Swift/BAT-GUANO
  67. Fermi trigger No 723412808: Global MASTER-Net observations report
  68. Konus-Wind detection of GRB 231129C
  69. GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
  70. GRB 231129B: Swift-XRT observations
  71. GRB 231129C: AGILE detection
  72. GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
  73. GRB 231129A: Swift-BAT refined analysis
  74. GRB 231129C: MASTER OT detection
  75. GRB 231129C: Fermi-LAT detection
  76. GRB 231129C: GRBAlpha detection
  77. GRB 231129C: Glowbug gamma-ray detection
  78. GRB 231129C: GECAM-B detection of a bright burst
  79. GRB 231129C: AstroSat CZTI detection
  80. GRB 231129C: CALET Gamma-Ray Burst Monitor detection
  81. GRB 231129C: Fermi GBM Observation of a very bright GRB
  82. GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
  83. GRB 231129C: MAXI/GSC detection
  84. GRB 231129B: Tiled Swift observations
  85. GRB 231129B: MAXI/GSC detection
  86. Fermi trigger No 722653947: Global MASTER-Net observations report
  87. Fermi trigger No 722400249: Global MASTER-Net observations report
  88. GRB 231117A: GTC Near-Infrared Observations
  89. Konus-Wind detection of GRB 231020A
  90. GRB 231117A : MITSuME Akeno optical afterglow candidate detection
  91. LIGO/Virgo/KAGRA S231119ab: Coverage and upper limits from MAXI/GSC observations
  92. Fermi trigger No 722039659: Global MASTER-Net observations report
  93. GRB 231115A : OHP/T120 optical upper limit
  94. GRB 231117A : MITSuME Akeno optical upper limits
  95. Fermi GRB 231115A: Global MASTER-Net observations report
  96. GRB 231113A (short): Glowbug gamma-ray detection
  97. LIGO/Virgo/KAGRA S231113cd: Coverage and upper limits from MAXI/GSC observations
  98. LIGO/Virgo/KAGRA S231113bw: Coverage and upper limits from MAXI/GSC observations
  99. Swift GRB231111.60: Global MASTER-Net observations report
  100. Fermi trigger No 721204446: Global MASTER-Net observations report

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