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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

32764 results found.

  1. GRB 251130B: Glowbug gamma-ray detection
  2. GRB 251201B: GECAM-B observation of a long burst
  3. EP251130a: continued NOT optical observations indicate steep fading phase
  4. GRB 251122A/EP251122a: CrAO ZTSh optical observations
  5. Fermi-LAT Gamma-ray Observations of IceCube-251130A
  6. EP251202a / GRB 251202A: LCO r- and i-band optical detection
  7. GRB 251202A: GOTO optical afterglow detection
  8. EP251202a/GRB 251202A: refined analysis of the EP-WXT observations
  9. GRB 251201A: GECAM-B observation of a burst
  10. GRB 251126A: SAO RAS optical marginal detection
  11. GRB 251202A: Swift-XRT afterglow detection
  12. EP251129a/GRB 251129A: NOWT Detection
  13. GRB 251126A: SVOM/VT optical observation
  14. EP251130a: SVOM/VT optical observation
  15. EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
  16. Fermi GRB 251202A: Global MASTER-Net observations report
  17. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  18. IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube
  19. GRB 251201A: SVOM/GRM observation of a burst
  20. GRB 251201B: SVOM/VT optical fading
  21. Swift GRB 251201B : MASTER optical counterpart detection
  22. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  23. Swift GRB 251201B: Global MASTER-Net observations report
  24. EP251118a: Mondy, CrAO, Assy and SAO RAS/Zeiss-1000 optical observations
  25. GRB 251130B: AstroSat CZTI detection
  26. EP251130a: Mondy optical observations
  27. EP251130a: Optical detections with Kinder observations
  28. EP251130a: SAO RAS optical observations
  29. EP251130a: GTC OSIRIS+ redshift z = 4.035 and rebrightening
  30. EP251130a: KAIT optical observations
  31. EP251130A: Optical observation from 1.3m DFOT
  32. EP251130a: refined analysis of the EP-WXT and EP-FXT observations
  33. EP251130a: JinShan optical observations
  34. Fermi GRB 251130B: Global MASTER-Net observations report
  35. GRB 251127A: SVOM/GRM observation
  36. EP251130a: Swift-XRT counterpart detection
  37. EP251130a: Global MASTER-Net observations report
  38. EP251130a: COLIBRÍ optical counterpart candidate
  39. EP251129a/GRB 251129A: EP-FXT follow-up observations
  40. GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
  41. GRB 251128A: AstroSat CZTI detection
  42. GRB 251129A / EP251129a: SAO RAS optical observations
  43. GRB 251126A: SAO RAS optical observations
  44. GRB 251128A: GECAM-B detection
  45. GRB 251128A: SVOM/GRM observation of a long burst
  46. GRB 251128A: Insight-HXMT/HE detection
  47. SVOM GRB 251129A : MASTER optical counterpart detection
  48. GRB 251129A: Swift-XRT afterglow detection
  49. GRB 251129A: Swift ToO observations
  50. GRB 251129A / EP251129a: SVOM/VT optical fading
  51. EP251129a: Global MASTER-Net observations report
  52. GRB 251129A: Optical Observations via Virtual Telescope Project, Italy
  53. EP251129a/GRB 251129A : Einstein Probe detection of an X-ray transient
  54. GRB 251129A: Correction to the position of the optical counterpar
  55. GRB 251129A: SVOM/VT optical counterpart confirmation with VHF data
  56. GRB 251128A: Fermi GBM Observation
  57. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  58. GRB 251126A: Swift-BAT refined analysis
  59. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  60. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  61. Fermi GRB 251128A: Global MASTER-Net observations report
  62. GRB 251127A: Glowbug gamma-ray detection
  63. GRB 251126A: OHP/T193 optical observations and tentative spectroscopic redshift
  64. GRB 251126A: further SAO RAS optical observations
  65. GRB 250702B: detection of the compact radio counterpart 139 days after the burst
  66. GRB 251126A NUTTelA-TAO Early Measurements
  67. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  68. GRB251126A: MAO/AZT-22 optical observations
  69. GRB251126A: Continued optical observation from 1.3m DFOT
  70. GRB 251126A: Swift/UVOT Detection
  71. EP251124a: Pan-STARRS ri-band imaging and photometry
  72. GRB 251126A: Mondy and SAO RAS optical observations
  73. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  74. GRB 251126A: NOT optical observations
  75. GRB 251126A: 1.3m DFOT optical afterglow detection
  76. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  77. GRB 251126A: COLIBRÍ photometric redshift z = 3.5
  78. GRB 251125B: GECAM-B detection
  79. Fermi GRB 251127A: Global MASTER-Net observations report
  80. GRB 251126A: Kilonova-Catcher optical afterglow detection
  81. GRB 251126A: Asiago i-band detection
  82. GRB 251126A: Nanshan/HMT optical afterglow detection
  83. Swift GRB 251126A: Global MASTER-Net observations report
  84. GRB 251121A: Fermi GBM Observation
  85. GRB 251126A: GIT discovery of the likely optical afterglow
  86. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  87. EP251124b follow-up observation by EP-FXT
  88. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  89. EP251124b: NOT r- and z-band optical upper limits
  90. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  91. Fermi GRB 251125B: Global MASTER-Net observations report
  92. EP251124b: Global MASTER-Net observations report
  93. EP251124a: Xinglong GWAC-F60A optical observation
  94. EP251124a (EP-WXT trigger 01709248862) is triggered by the known source AWM 7
  95. Fermi GRB 251125A: Global MASTER-Net observations report
  96. EP251124a: NOT r- and z-band optical upper limits
  97. EP251124a: Global MASTER-Net observations report
  98. GRB 251124A: Fermi GBM Localization by automated pipeline
  99. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  100. EP251124a: Optical upper limit with Kinder observations

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