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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"

32752 results found.

  1. EP251130a: SVOM/VT optical observation
  2. EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
  3. Fermi GRB 251202A: Global MASTER-Net observations report
  4. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  5. IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube
  6. GRB 251201A: SVOM/GRM observation of a burst
  7. GRB 251201B: SVOM/VT optical fading
  8. Swift GRB 251201B : MASTER optical counterpart detection
  9. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  10. Swift GRB 251201B: Global MASTER-Net observations report
  11. EP251118a: Mondy, CrAO, Assy and SAO RAS/Zeiss-1000 optical observations
  12. GRB 251130B: AstroSat CZTI detection
  13. EP251130a: Mondy optical observations
  14. EP251130a: Optical detections with Kinder observations
  15. EP251130a: SAO RAS optical observations
  16. EP251130a: GTC OSIRIS+ redshift z = 4.035 and rebrightening
  17. EP251130a: KAIT optical observations
  18. EP251130A: Optical observation from 1.3m DFOT
  19. EP251130a: refined analysis of the EP-WXT and EP-FXT observations
  20. EP251130a: JinShan optical observations
  21. Fermi GRB 251130B: Global MASTER-Net observations report
  22. GRB 251127A: SVOM/GRM observation
  23. EP251130a: Swift-XRT counterpart detection
  24. EP251130a: Global MASTER-Net observations report
  25. EP251130a: COLIBRÍ optical counterpart candidate
  26. EP251129a/GRB 251129A: EP-FXT follow-up observations
  27. GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
  28. GRB 251128A: AstroSat CZTI detection
  29. GRB 251129A / EP251129a: SAO RAS optical observations
  30. GRB 251126A: SAO RAS optical observations
  31. GRB 251128A: GECAM-B detection
  32. GRB 251128A: SVOM/GRM observation of a long burst
  33. GRB 251128A: Insight-HXMT/HE detection
  34. SVOM GRB 251129A : MASTER optical counterpart detection
  35. GRB 251129A: Swift-XRT afterglow detection
  36. GRB 251129A: Swift ToO observations
  37. GRB 251129A / EP251129a: SVOM/VT optical fading
  38. EP251129a: Global MASTER-Net observations report
  39. GRB 251129A: Optical Observations via Virtual Telescope Project, Italy
  40. EP251129a/GRB 251129A : Einstein Probe detection of an X-ray transient
  41. GRB 251129A: Correction to the position of the optical counterpar
  42. GRB 251129A: SVOM/VT optical counterpart confirmation with VHF data
  43. GRB 251128A: Fermi GBM Observation
  44. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  45. GRB 251126A: Swift-BAT refined analysis
  46. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  47. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  48. Fermi GRB 251128A: Global MASTER-Net observations report
  49. GRB 251127A: Glowbug gamma-ray detection
  50. GRB 251126A: OHP/T193 optical observations and tentative spectroscopic redshift
  51. GRB 251126A: further SAO RAS optical observations
  52. GRB 250702B: detection of the compact radio counterpart 139 days after the burst
  53. GRB 251126A NUTTelA-TAO Early Measurements
  54. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  55. GRB251126A: MAO/AZT-22 optical observations
  56. GRB251126A: Continued optical observation from 1.3m DFOT
  57. GRB 251126A: Swift/UVOT Detection
  58. EP251124a: Pan-STARRS ri-band imaging and photometry
  59. GRB 251126A: Mondy and SAO RAS optical observations
  60. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  61. GRB 251126A: NOT optical observations
  62. GRB 251126A: 1.3m DFOT optical afterglow detection
  63. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  64. GRB 251126A: COLIBRÍ photometric redshift z = 3.5
  65. GRB 251125B: GECAM-B detection
  66. Fermi GRB 251127A: Global MASTER-Net observations report
  67. GRB 251126A: Kilonova-Catcher optical afterglow detection
  68. GRB 251126A: Asiago i-band detection
  69. GRB 251126A: Nanshan/HMT optical afterglow detection
  70. Swift GRB 251126A: Global MASTER-Net observations report
  71. GRB 251121A: Fermi GBM Observation
  72. GRB 251126A: GIT discovery of the likely optical afterglow
  73. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  74. EP251124b follow-up observation by EP-FXT
  75. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  76. EP251124b: NOT r- and z-band optical upper limits
  77. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  78. Fermi GRB 251125B: Global MASTER-Net observations report
  79. EP251124b: Global MASTER-Net observations report
  80. EP251124a: Xinglong GWAC-F60A optical observation
  81. EP251124a (EP-WXT trigger 01709248862) is triggered by the known source AWM 7
  82. Fermi GRB 251125A: Global MASTER-Net observations report
  83. EP251124a: NOT r- and z-band optical upper limits
  84. EP251124a: Global MASTER-Net observations report
  85. GRB 251124A: Fermi GBM Localization by automated pipeline
  86. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  87. EP251124a: Optical upper limit with Kinder observations
  88. EP251118A: 6 GHz VLA Detection
  89. Fermi GRB 251124a: Global MASTER-Net observations report
  90. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  91. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  92. EP251124a: GROWTH-India Telescope optical upper limits
  93. GRB 251116C: Swift-XRT confirmation of fading
  94. GRB 251122A/EP251122a: FTW optical and NIR observations
  95. GRB 251122A/EP251122A: 1.3m DFOT optical detection
  96. GRB 251122A / EP251122a: Xinglong 2.16m optical observation
  97. EP251118A: 3.6m DOT optical afterglow detection
  98. GRB 251122A / EP251122a: EP-FXT counterpart detection
  99. EP251122a: refined analysis of the EP-WXT and EP-FXT observations
  100. GRB 251122A / EP251122a: WFST optical observations

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