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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"

42983 results found.

  1. Swift GRB 251201B: Global MASTER-Net observations report
  2. GRB 251201B: Enhanced Swift-XRT position
  3. EP251118a: Mondy, CrAO, Assy and SAO RAS/Zeiss-1000 optical observations
  4. GRB 251130B: AstroSat CZTI detection
  5. GRB 251201B: Swift detection of a burst with an optical counterpart
  6. GRB 251201B: Fermi GBM Final Real-time Localization
  7. EP251130a: Mondy optical observations
  8. EP251130a: Optical detections with Kinder observations
  9. SVOM GRB251201.19: Global MASTER-Net observations report
  10. EP251130a: SAO RAS optical observations
  11. EP251130a: GTC OSIRIS+ redshift z = 4.035 and rebrightening
  12. EP251130a: KAIT optical observations
  13. EP251130A: Optical observation from 1.3m DFOT
  14. EP251130a: refined analysis of the EP-WXT and EP-FXT observations
  15. EP251130a: JinShan optical observations
  16. GRB 251201A: MAXI/GSC detection
  17. Fermi GRB 251130B: Global MASTER-Net observations report
  18. GRB 251127A: SVOM/GRM observation
  19. IceCube Alert 251130.75: Global MASTER-Net observations report
  20. IceCube-251130A - IceCube observation of a high-energy neutrino candidate track-like event
  21. EP251130a: Swift-XRT counterpart detection
  22. GRB 251130B: Fermi GBM Final Localization Correction
  23. EP251130a: Global MASTER-Net observations report
  24. GRB 251130B: Fermi GBM Final Real-time Localization
  25. EP251130a: COLIBRÍ optical counterpart candidate
  26. EP251130a: Einstein Probe detection of an X-ray transient
  27. EP251129a/GRB 251129A: EP-FXT follow-up observations
  28. GRB 251130A: Fermi GBM Final Real-time Localization
  29. GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
  30. GRB 251129A / EP251129a: OSN and CAHA optical follow-up
  31. GRB 251128A: AstroSat CZTI detection
  32. GRB 251129A / EP251129a: SAO RAS optical observations
  33. GRB 251126A: SAO RAS optical observations
  34. GRB 251128A: GECAM-B detection
  35. GRB 251128A: SVOM/GRM observation of a long burst
  36. GRB 251128A: Insight-HXMT/HE detection
  37. SVOM GRB 251129A : MASTER optical counterpart detection
  38. GRB 251129A: Swift-XRT afterglow detection
  39. The EP-WXT trigger 01709248941 is triggered by the known source Perseus Cluster
  40. Swift trigger 1418333 is not an astrophysical source
  41. GRB 251129A: Swift ToO observations
  42. GRB 251129A / EP251129a: SVOM/VT optical fading
  43. EP251129a: Global MASTER-Net observations report
  44. EP251129a/GRB 251129A : Einstein Probe detection of an X-ray transient
  45. GRB 251129A: SVOM/VT optical counterpart confirmation with VHF data
  46. GRB 251128A: Fermi GBM Observation
  47. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  48. GRB 251129A: SVOM detection of a burst
  49. SVOM GRB251129A: Global MASTER-Net observations report
  50. GRB 251129A: SVOM detection of a burst
  51. GRB 251126A: Swift-BAT refined analysis
  52. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  53. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  54. Fermi GRB 251128A: Global MASTER-Net observations report
  55. GRB 251127A: Glowbug gamma-ray detection
  56. GRB 251126A: OHP/T193 optical observations and tentative spectroscopic redshift
  57. GRB 251126A: further SAO RAS optical observations
  58. GRB 250702B: detection of the compact radio counterpart 139 days after the burst
  59. GRB 251126A NUTTelA-TAO Early Measurements
  60. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  61. GRB251126A: MAO/AZT-22 optical observations
  62. GRB 251128A: Fermi GBM Final Real-time Localization
  63. GRB251126A: Continued optical observation from 1.3m DFOT
  64. GRB 251126A: Swift/UVOT Detection
  65. EP251124a: Pan-STARRS ri-band imaging and photometry
  66. GRB 251126A: Mondy and SAO RAS optical observations
  67. GRB 251126A: Swift-XRT refined Analysis
  68. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  69. GRB 251126A: NOT optical observations
  70. GRB 251126A: 1.3m DFOT optical afterglow detection
  71. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  72. GRB 251126A: COLIBRÍ photometric redshift z = 3.5
  73. GRB 251125B: GECAM-B detection
  74. Fermi GRB 251127A: Global MASTER-Net observations report
  75. GRB 251127A: Fermi GBM Final Real-time Localization
  76. GRB 251126A: Enhanced Swift-XRT position
  77. GRB 251126A: Kilonova-Catcher optical afterglow detection
  78. GRB 251126A: Asiago i-band detection
  79. GRB 251126A: Nanshan/HMT optical afterglow detection
  80. Swift GRB 251126A: Global MASTER-Net observations report
  81. GRB 251121A: Fermi GBM Observation
  82. GRB 251126A: Prompt enhanced Swift-XRT position
  83. GRB 251126A: GIT discovery of the likely optical afterglow
  84. GRB 251126A: Swift detection of a burst
  85. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  86. EP251124b follow-up observation by EP-FXT
  87. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  88. EP251124b: NOT r- and z-band optical upper limits
  89. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  90. Fermi GRB 251125B: Global MASTER-Net observations report
  91. GRB 251125B: Fermi GBM Final Real-time Localization
  92. EP251124b: Global MASTER-Net observations report
  93. EP251124b: EP-WXT detection of a fast X-ray transient
  94. EP251124a: Xinglong GWAC-F60A optical observation
  95. EP251124a (EP-WXT trigger 01709248862) is triggered by the known source AWM 7
  96. Fermi GRB 251125A: Global MASTER-Net observations report
  97. GRB 251125A: Fermi GBM Final Real-time Localization
  98. EP251124a: NOT r- and z-band optical upper limits
  99. EP251124a: Global MASTER-Net observations report
  100. EP251124a: Swift-XRT observations

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