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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"

29107 results found.

  1. GRB 251203B: SVOM detection of a burst
  2. GRB 251201B: Insight-HXMT/HE detection
  3. EP251202a / GRB 251202A: Insight-HXMT/HE detection
  4. GRB 251203A: Fermi GBM Final Real-time Localization
  5. EP251202a / GRB251202A: AstroSat CZTI detection
  6. GRB 251202A / EP251202a: SVOM/VT optical observation
  7. GRB 251201B: Fermi GBM Observation
  8. EP251202a/GRB 251202A: KAIT optical observations
  9. EP251130a: ULL-ASTRO-MASTER late detection of the optical afterglow with LCO 1-m telescope at Teide Observatory
  10. Fermi GRB 251202B: Global MASTER-Net observations report
  11. GRB 251202B: Fermi GBM Final Real-time Localization
  12. GRB251129A/EP251129a: Swift UVOT detection
  13. GRB 251202A: Fermi GBM Observation
  14. GRB 251202A: Swift/UVOT Detection
  15. GRB 251201B: Kilonova-Catcher optical afterglow detection
  16. GRB 251201B: Swift/UVOT Detection
  17. GRB 251130B: Glowbug gamma-ray detection
  18. GRB 251201B: GECAM-B observation of a long burst
  19. EP251130a: continued NOT optical observations indicate steep fading phase
  20. Fermi-LAT Gamma-ray Observations of IceCube-251130A
  21. EP251202a / GRB 251202A: LCO r- and i-band optical detection
  22. GRB 251202A: GOTO optical afterglow detection
  23. GRB 251126A: SVOM/VT optical observation
  24. EP251130a: SVOM/VT optical observation
  25. EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
  26. Fermi GRB 251202A: Global MASTER-Net observations report
  27. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  28. GRB 251201B: Swift-XRT refined Analysis
  29. EP251202a/trigger 01709249064: Las Cumbres discovery of the optical counterpart
  30. GRB 251202A: Fermi GBM Final Real-time Localization
  31. GRB 251201A: SVOM/GRM observation of a burst
  32. GRB 251201B: SVOM/VT optical fading
  33. Swift GRB 251201B : MASTER optical counterpart detection
  34. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  35. Swift GRB 251201B: Global MASTER-Net observations report
  36. GRB 251130B: AstroSat CZTI detection
  37. GRB 251201B: Swift detection of a burst with an optical counterpart
  38. GRB 251201B: Fermi GBM Final Real-time Localization
  39. EP251130a: Optical detections with Kinder observations
  40. SVOM GRB251201.19: Global MASTER-Net observations report
  41. EP251130a: GTC OSIRIS+ redshift z = 4.035 and rebrightening
  42. EP251130A: Optical observation from 1.3m DFOT
  43. Fermi GRB 251130B: Global MASTER-Net observations report
  44. GRB 251127A: SVOM/GRM observation
  45. IceCube Alert 251130.75: Global MASTER-Net observations report
  46. IceCube-251130A - IceCube observation of a high-energy neutrino candidate track-like event
  47. EP251130a: Swift-XRT counterpart detection
  48. GRB 251130B: Fermi GBM Final Localization Correction
  49. EP251130a: Global MASTER-Net observations report
  50. GRB 251130B: Fermi GBM Final Real-time Localization
  51. EP251130a: COLIBRÍ optical counterpart candidate
  52. GRB 251130A: Fermi GBM Final Real-time Localization
  53. GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
  54. GRB 251128A: AstroSat CZTI detection
  55. GRB 251128A: GECAM-B detection
  56. GRB 251128A: SVOM/GRM observation of a long burst
  57. GRB 251128A: Insight-HXMT/HE detection
  58. SVOM GRB 251129A : MASTER optical counterpart detection
  59. The EP-WXT trigger 01709248941 is triggered by the known source Perseus Cluster
  60. Swift trigger 1418333 is not an astrophysical source
  61. GRB 251129A / EP251129a: SVOM/VT optical fading
  62. EP251129a: Global MASTER-Net observations report
  63. GRB 251129A: SVOM/VT optical counterpart confirmation with VHF data
  64. GRB 251128A: Fermi GBM Observation
  65. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  66. GRB 251129A: SVOM detection of a burst
  67. SVOM GRB251129A: Global MASTER-Net observations report
  68. GRB 251129A: SVOM detection of a burst
  69. GRB 251126A: Swift-BAT refined analysis
  70. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  71. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  72. Fermi GRB 251128A: Global MASTER-Net observations report
  73. GRB 251127A: Glowbug gamma-ray detection
  74. GRB 250702B: detection of the compact radio counterpart 139 days after the burst
  75. GRB 251126A NUTTelA-TAO Early Measurements
  76. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  77. GRB251126A: MAO/AZT-22 optical observations
  78. GRB 251128A: Fermi GBM Final Real-time Localization
  79. GRB251126A: Continued optical observation from 1.3m DFOT
  80. GRB 251126A: Swift/UVOT Detection
  81. GRB 251126A: Mondy and SAO RAS optical observations
  82. GRB 251126A: Swift-XRT refined Analysis
  83. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  84. GRB 251126A: NOT optical observations
  85. GRB 251126A: 1.3m DFOT optical afterglow detection
  86. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  87. GRB 251126A: COLIBRÍ photometric redshift z = 3.5
  88. GRB 251125B: GECAM-B detection
  89. Fermi GRB 251127A: Global MASTER-Net observations report
  90. GRB 251127A: Fermi GBM Final Real-time Localization
  91. GRB 251126A: Asiago i-band detection
  92. GRB 251126A: Nanshan/HMT optical afterglow detection
  93. Swift GRB 251126A: Global MASTER-Net observations report
  94. GRB 251121A: Fermi GBM Observation
  95. GRB 251126A: GIT discovery of the likely optical afterglow
  96. GRB 251126A: Swift detection of a burst
  97. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  98. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  99. EP251124b: NOT r- and z-band optical upper limits
  100. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery

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