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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"

29110 results found.

  1. GRB 251203C: SVOM detection of a burst
  2. SVOM GRB251203.77: Global MASTER-Net observations report
  3. SVOM GRB251203B: Global MASTER-Net observations report
  4. GRB 251203B: SVOM detection of a burst
  5. GRB 251201B: Insight-HXMT/HE detection
  6. EP251202a / GRB 251202A: Insight-HXMT/HE detection
  7. GRB 251203A: Fermi GBM Final Real-time Localization
  8. EP251202a / GRB251202A: AstroSat CZTI detection
  9. GRB 251202A / EP251202a: SVOM/VT optical observation
  10. GRB 251201B: Fermi GBM Observation
  11. EP251202a/GRB 251202A: KAIT optical observations
  12. EP251130a: ULL-ASTRO-MASTER late detection of the optical afterglow with LCO 1-m telescope at Teide Observatory
  13. Fermi GRB 251202B: Global MASTER-Net observations report
  14. GRB 251202B: Fermi GBM Final Real-time Localization
  15. GRB251129A/EP251129a: Swift UVOT detection
  16. GRB 251202A: Fermi GBM Observation
  17. GRB 251202A: Swift/UVOT Detection
  18. GRB 251201B: Kilonova-Catcher optical afterglow detection
  19. GRB 251201B: Swift/UVOT Detection
  20. GRB 251130B: Glowbug gamma-ray detection
  21. GRB 251201B: GECAM-B observation of a long burst
  22. EP251130a: continued NOT optical observations indicate steep fading phase
  23. Fermi-LAT Gamma-ray Observations of IceCube-251130A
  24. EP251202a / GRB 251202A: LCO r- and i-band optical detection
  25. GRB 251202A: GOTO optical afterglow detection
  26. GRB 251126A: SVOM/VT optical observation
  27. EP251130a: SVOM/VT optical observation
  28. EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
  29. Fermi GRB 251202A: Global MASTER-Net observations report
  30. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  31. GRB 251201B: Swift-XRT refined Analysis
  32. EP251202a/trigger 01709249064: Las Cumbres discovery of the optical counterpart
  33. GRB 251202A: Fermi GBM Final Real-time Localization
  34. GRB 251201A: SVOM/GRM observation of a burst
  35. GRB 251201B: SVOM/VT optical fading
  36. Swift GRB 251201B : MASTER optical counterpart detection
  37. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  38. Swift GRB 251201B: Global MASTER-Net observations report
  39. GRB 251130B: AstroSat CZTI detection
  40. GRB 251201B: Swift detection of a burst with an optical counterpart
  41. GRB 251201B: Fermi GBM Final Real-time Localization
  42. EP251130a: Optical detections with Kinder observations
  43. SVOM GRB251201.19: Global MASTER-Net observations report
  44. EP251130a: GTC OSIRIS+ redshift z = 4.035 and rebrightening
  45. EP251130A: Optical observation from 1.3m DFOT
  46. Fermi GRB 251130B: Global MASTER-Net observations report
  47. GRB 251127A: SVOM/GRM observation
  48. IceCube Alert 251130.75: Global MASTER-Net observations report
  49. IceCube-251130A - IceCube observation of a high-energy neutrino candidate track-like event
  50. EP251130a: Swift-XRT counterpart detection
  51. GRB 251130B: Fermi GBM Final Localization Correction
  52. EP251130a: Global MASTER-Net observations report
  53. GRB 251130B: Fermi GBM Final Real-time Localization
  54. EP251130a: COLIBRÍ optical counterpart candidate
  55. GRB 251130A: Fermi GBM Final Real-time Localization
  56. GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
  57. GRB 251128A: AstroSat CZTI detection
  58. GRB 251128A: GECAM-B detection
  59. GRB 251128A: SVOM/GRM observation of a long burst
  60. GRB 251128A: Insight-HXMT/HE detection
  61. SVOM GRB 251129A : MASTER optical counterpart detection
  62. The EP-WXT trigger 01709248941 is triggered by the known source Perseus Cluster
  63. Swift trigger 1418333 is not an astrophysical source
  64. GRB 251129A / EP251129a: SVOM/VT optical fading
  65. EP251129a: Global MASTER-Net observations report
  66. GRB 251129A: SVOM/VT optical counterpart confirmation with VHF data
  67. GRB 251128A: Fermi GBM Observation
  68. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  69. GRB 251129A: SVOM detection of a burst
  70. SVOM GRB251129A: Global MASTER-Net observations report
  71. GRB 251129A: SVOM detection of a burst
  72. GRB 251126A: Swift-BAT refined analysis
  73. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  74. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  75. Fermi GRB 251128A: Global MASTER-Net observations report
  76. GRB 251127A: Glowbug gamma-ray detection
  77. GRB 250702B: detection of the compact radio counterpart 139 days after the burst
  78. GRB 251126A NUTTelA-TAO Early Measurements
  79. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  80. GRB251126A: MAO/AZT-22 optical observations
  81. GRB 251128A: Fermi GBM Final Real-time Localization
  82. GRB251126A: Continued optical observation from 1.3m DFOT
  83. GRB 251126A: Swift/UVOT Detection
  84. GRB 251126A: Mondy and SAO RAS optical observations
  85. GRB 251126A: Swift-XRT refined Analysis
  86. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  87. GRB 251126A: NOT optical observations
  88. GRB 251126A: 1.3m DFOT optical afterglow detection
  89. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  90. GRB 251126A: COLIBRÍ photometric redshift z = 3.5
  91. GRB 251125B: GECAM-B detection
  92. Fermi GRB 251127A: Global MASTER-Net observations report
  93. GRB 251127A: Fermi GBM Final Real-time Localization
  94. GRB 251126A: Asiago i-band detection
  95. GRB 251126A: Nanshan/HMT optical afterglow detection
  96. Swift GRB 251126A: Global MASTER-Net observations report
  97. GRB 251121A: Fermi GBM Observation
  98. GRB 251126A: GIT discovery of the likely optical afterglow
  99. GRB 251126A: Swift detection of a burst
  100. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3

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