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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"

23701 results found.

  1. GRB 251208B: Fermi-LAT detection
  2. GRB 251206A: SVOM detection of a burst through offline search
  3. GRB 251205A : MITSuME Akeno optical afterglow candidate detection
  4. EP-WXT trigger 01709249380: KAIT confirmation of a stellar flare
  5. EP-WXT trigger 01709249380: confirmation of a stellar flare by BOOTES-5
  6. GRB 251205A: ZTF and ATLAS optical afterglow detections
  7. GRB 251205A: Swift-BAT refined analysis
  8. GRB 251205A: Swift-XRT refined Analysis
  9. Konus-Wind detection of GRB 251118A
  10. GRB 251205A: COLIBRÍ optical observations
  11. GRB 251205A: GOTO optical afterglow detection
  12. GRB 251205A: NOT optical observations
  13. GRB 251205A: GTC/OSIRIS+ redshift z = 1.100
  14. GRB 251205A: Swift detection of a burst with an optical afterglow
  15. GRB 251203C: SVOM/ECLAIRs refined analysis
  16. GRB 251202A / EP251202a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm and 1-m telescopes at McDonald Observatory
  17. GRB 251203C: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  18. GRB 251201B: SALT spectroscopic redshift z = 1.599
  19. GRB 251203C: J-band observations with WINTER
  20. GRB 251129B: Glowbug gamma-ray detection of a short burst
  21. GRB 251203A: AstroSat CZTI detection
  22. GRB 251203C: LCO optical afterglow confirmation
  23. GRB 251203C: SVOM/VT optical counterpart
  24. GRB 251129A/EP251129a : SVOM/ECLAIRs refined analysis
  25. GRB 251203B: Swift-XRT observations
  26. GRB 251203B: confirmation of a stellar flare by BOOTES-2
  27. GRB 251203B : SVOM trigger sb25120304 is not a GRB
  28. GRB 251203C: LCO optical upper limits
  29. GRB 251203B: LCO optical upper limits
  30. GRB 251203C: SVOM detection of a burst
  31. GRB 251203B: SVOM detection of a burst
  32. EP251202a / GRB251202A: AstroSat CZTI detection
  33. GRB 251201B: Fermi GBM Observation
  34. EP251202a/GRB 251202A: KAIT optical observations
  35. EP251130a: ULL-ASTRO-MASTER late detection of the optical afterglow with LCO 1-m telescope at Teide Observatory
  36. GRB 251129B: AstroSat CZTI detection
  37. GRB 251202A: Swift/UVOT Detection
  38. GRB 251201B: Kilonova-Catcher optical afterglow detection
  39. GRB 251201B: Swift/UVOT Detection
  40. GRB 251130B: Glowbug gamma-ray detection
  41. GRB 251201B: GECAM-B observation of a long burst
  42. GRB 251202A: GOTO optical afterglow detection
  43. EP251202a/GRB 251202A: refined analysis of the EP-WXT observations
  44. GRB 251202A: Swift-XRT afterglow detection
  45. EP251129a/GRB 251129A: NOWT Detection
  46. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  47. GRB 251201B: Swift-XRT refined Analysis
  48. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  49. Swift GRB 251201B: Global MASTER-Net observations report
  50. EP251118a: Mondy, CrAO, Assy and SAO RAS/Zeiss-1000 optical observations
  51. GRB 251130B: AstroSat CZTI detection
  52. GRB 251201B: Swift detection of a burst with an optical counterpart
  53. EP251130a: Optical detections with Kinder observations
  54. EP251130a: KAIT optical observations
  55. GRB 251201A: MAXI/GSC detection
  56. EP251130a: Swift-XRT counterpart detection
  57. EP251130a: COLIBRÍ optical counterpart candidate
  58. GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
  59. GRB 251129A / EP251129a: OSN and CAHA optical follow-up
  60. GRB 251128A: AstroSat CZTI detection
  61. GRB 251129A / EP251129a: SAO RAS optical observations
  62. Swift trigger 1418333 is not an astrophysical source
  63. GRB 251128A: Fermi GBM Observation
  64. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  65. GRB 251126A: Swift-BAT refined analysis
  66. GRB 251127A: Glowbug gamma-ray detection
  67. GRB 251126A: OHP/T193 optical observations and tentative spectroscopic redshift
  68. GRB 250702B: detection of the compact radio counterpart 139 days after the burst
  69. GRB 251126A NUTTelA-TAO Early Measurements
  70. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  71. EP251124a: Pan-STARRS ri-band imaging and photometry
  72. GRB 251126A: Swift-XRT refined Analysis
  73. GRB 251126A : MITSuME Akeno optical afterglow candidate 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 251126A: Kilonova-Catcher optical afterglow detection
  77. GRB 251126A: Swift detection of a burst
  78. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  79. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  80. EP251124a: Swift-XRT observations
  81. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  82. EP251124a: Optical upper limit with Kinder observations
  83. EP251118A: 6 GHz VLA Detection
  84. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  85. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  86. GRB 251116C: Swift-XRT confirmation of fading
  87. EP251122a / GRB 251122A: optical counterpart candidate with Kinder observations
  88. GRB 251122A/EP251122a: SVOM/C-GFT upper limit
  89. GRB 251122A / EP251122a: SVOM detection of a long burst
  90. EP251118a: Continued Optical Detection with Kinder observations
  91. LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
  92. GRB 251121A: Glowbug gamma-ray detection of a likely short burst
  93. GRB 251115A: Fermi GBM Observation
  94. GRB 251118A: Swift/UVOT Detection
  95. EP251118a / GRB 251118C: SAO RAS optical observations
  96. GRB 251118A: Glowbug gamma-ray detection
  97. GRB 251118A: Swift-XRT afterglow detection
  98. EP251118a: Optical detection with Kinder observations
  99. EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
  100. GRB 251118C: Glowbug gamma-ray detection of the fast X-ray transient EP251118A

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