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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').
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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"

32762 results found.

  1. EP251130a: continued NOT optical observations indicate steep fading phase
  2. GRB 251122A/EP251122a: CrAO ZTSh optical observations
  3. Fermi-LAT Gamma-ray Observations of IceCube-251130A
  4. EP251202a / GRB 251202A: LCO r- and i-band optical detection
  5. GRB 251202A: GOTO optical afterglow detection
  6. EP251202a/GRB 251202A: refined analysis of the EP-WXT observations
  7. GRB 251201A: GECAM-B observation of a burst
  8. GRB 251126A: SAO RAS optical marginal detection
  9. GRB 251202A: Swift-XRT afterglow detection
  10. EP251129a/GRB 251129A: NOWT Detection
  11. GRB 251126A: SVOM/VT optical observation
  12. EP251130a: SVOM/VT optical observation
  13. EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
  14. Fermi GRB 251202A: Global MASTER-Net observations report
  15. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  16. IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube
  17. GRB 251201A: SVOM/GRM observation of a burst
  18. GRB 251201B: SVOM/VT optical fading
  19. Swift GRB 251201B : MASTER optical counterpart detection
  20. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  21. Swift GRB 251201B: Global MASTER-Net observations report
  22. EP251118a: Mondy, CrAO, Assy and SAO RAS/Zeiss-1000 optical observations
  23. GRB 251130B: AstroSat CZTI detection
  24. EP251130a: Mondy optical observations
  25. EP251130a: Optical detections with Kinder observations
  26. EP251130a: SAO RAS optical observations
  27. EP251130a: GTC OSIRIS+ redshift z = 4.035 and rebrightening
  28. EP251130a: KAIT optical observations
  29. EP251130A: Optical observation from 1.3m DFOT
  30. EP251130a: refined analysis of the EP-WXT and EP-FXT observations
  31. EP251130a: JinShan optical observations
  32. Fermi GRB 251130B: Global MASTER-Net observations report
  33. GRB 251127A: SVOM/GRM observation
  34. EP251130a: Swift-XRT counterpart detection
  35. EP251130a: Global MASTER-Net observations report
  36. EP251130a: COLIBRÍ optical counterpart candidate
  37. EP251129a/GRB 251129A: EP-FXT follow-up observations
  38. GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
  39. GRB 251128A: AstroSat CZTI detection
  40. GRB 251129A / EP251129a: SAO RAS optical observations
  41. GRB 251126A: SAO RAS optical observations
  42. GRB 251128A: GECAM-B detection
  43. GRB 251128A: SVOM/GRM observation of a long burst
  44. GRB 251128A: Insight-HXMT/HE detection
  45. SVOM GRB 251129A : MASTER optical counterpart detection
  46. GRB 251129A: Swift-XRT afterglow detection
  47. GRB 251129A: Swift ToO observations
  48. GRB 251129A / EP251129a: SVOM/VT optical fading
  49. EP251129a: Global MASTER-Net observations report
  50. GRB 251129A: Optical Observations via Virtual Telescope Project, Italy
  51. EP251129a/GRB 251129A : Einstein Probe detection of an X-ray transient
  52. GRB 251129A: Correction to the position of the optical counterpar
  53. GRB 251129A: SVOM/VT optical counterpart confirmation with VHF data
  54. GRB 251128A: Fermi GBM Observation
  55. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  56. GRB 251126A: Swift-BAT refined analysis
  57. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  58. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  59. Fermi GRB 251128A: Global MASTER-Net observations report
  60. GRB 251127A: Glowbug gamma-ray detection
  61. GRB 251126A: OHP/T193 optical observations and tentative spectroscopic redshift
  62. GRB 251126A: further SAO RAS optical observations
  63. GRB 250702B: detection of the compact radio counterpart 139 days after the burst
  64. GRB 251126A NUTTelA-TAO Early Measurements
  65. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  66. GRB251126A: MAO/AZT-22 optical observations
  67. GRB251126A: Continued optical observation from 1.3m DFOT
  68. GRB 251126A: Swift/UVOT Detection
  69. EP251124a: Pan-STARRS ri-band imaging and photometry
  70. GRB 251126A: Mondy and SAO RAS optical observations
  71. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  72. GRB 251126A: NOT optical observations
  73. GRB 251126A: 1.3m DFOT optical afterglow detection
  74. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  75. GRB 251126A: COLIBRÍ photometric redshift z = 3.5
  76. GRB 251125B: GECAM-B detection
  77. Fermi GRB 251127A: Global MASTER-Net observations report
  78. GRB 251126A: Kilonova-Catcher optical afterglow detection
  79. GRB 251126A: Asiago i-band detection
  80. GRB 251126A: Nanshan/HMT optical afterglow detection
  81. Swift GRB 251126A: Global MASTER-Net observations report
  82. GRB 251121A: Fermi GBM Observation
  83. GRB 251126A: GIT discovery of the likely optical afterglow
  84. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  85. EP251124b follow-up observation by EP-FXT
  86. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  87. EP251124b: NOT r- and z-band optical upper limits
  88. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  89. Fermi GRB 251125B: Global MASTER-Net observations report
  90. EP251124b: Global MASTER-Net observations report
  91. EP251124a: Xinglong GWAC-F60A optical observation
  92. EP251124a (EP-WXT trigger 01709248862) is triggered by the known source AWM 7
  93. Fermi GRB 251125A: Global MASTER-Net observations report
  94. EP251124a: NOT r- and z-band optical upper limits
  95. EP251124a: Global MASTER-Net observations report
  96. GRB 251124A: Fermi GBM Localization by automated pipeline
  97. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  98. EP251124a: Optical upper limit with Kinder observations
  99. EP251118A: 6 GHz VLA Detection
  100. Fermi GRB 251124a: Global MASTER-Net observations report

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