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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"

23690 results found.

  1. GRB 251205A: NOT optical observations
  2. GRB 251205A: GTC/OSIRIS+ redshift z = 1.100
  3. GRB 251205A: Swift detection of a burst with an optical afterglow
  4. GRB 251203C: SVOM/ECLAIRs refined analysis
  5. GRB 251202A / EP251202a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm and 1-m telescopes at McDonald Observatory
  6. GRB 251203C: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  7. GRB 251201B: SALT spectroscopic redshift z = 1.599
  8. GRB 251203C: J-band observations with WINTER
  9. GRB 251129B: Glowbug gamma-ray detection of a short burst
  10. GRB 251203A: AstroSat CZTI detection
  11. GRB 251203C: LCO optical afterglow confirmation
  12. GRB 251203C: SVOM/VT optical counterpart
  13. GRB 251129A/EP251129a : SVOM/ECLAIRs refined analysis
  14. GRB 251203B: Swift-XRT observations
  15. GRB 251203B: confirmation of a stellar flare by BOOTES-2
  16. GRB 251203B : SVOM trigger sb25120304 is not a GRB
  17. GRB 251203C: LCO optical upper limits
  18. GRB 251203B: LCO optical upper limits
  19. GRB 251203C: SVOM detection of a burst
  20. GRB 251203B: SVOM detection of a burst
  21. EP251202a / GRB251202A: AstroSat CZTI detection
  22. GRB 251201B: Fermi GBM Observation
  23. EP251202a/GRB 251202A: KAIT optical observations
  24. EP251130a: ULL-ASTRO-MASTER late detection of the optical afterglow with LCO 1-m telescope at Teide Observatory
  25. GRB 251129B: AstroSat CZTI detection
  26. GRB 251202A: Swift/UVOT Detection
  27. GRB 251201B: Kilonova-Catcher optical afterglow detection
  28. GRB 251201B: Swift/UVOT Detection
  29. GRB 251130B: Glowbug gamma-ray detection
  30. GRB 251201B: GECAM-B observation of a long burst
  31. GRB 251202A: GOTO optical afterglow detection
  32. EP251202a/GRB 251202A: refined analysis of the EP-WXT observations
  33. GRB 251202A: Swift-XRT afterglow detection
  34. EP251129a/GRB 251129A: NOWT Detection
  35. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  36. GRB 251201B: Swift-XRT refined Analysis
  37. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  38. Swift GRB 251201B: Global MASTER-Net observations report
  39. EP251118a: Mondy, CrAO, Assy and SAO RAS/Zeiss-1000 optical observations
  40. GRB 251130B: AstroSat CZTI detection
  41. GRB 251201B: Swift detection of a burst with an optical counterpart
  42. EP251130a: Optical detections with Kinder observations
  43. EP251130a: KAIT optical observations
  44. GRB 251201A: MAXI/GSC detection
  45. EP251130a: Swift-XRT counterpart detection
  46. EP251130a: COLIBRÍ optical counterpart candidate
  47. GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
  48. GRB 251129A / EP251129a: OSN and CAHA optical follow-up
  49. GRB 251128A: AstroSat CZTI detection
  50. GRB 251129A / EP251129a: SAO RAS optical observations
  51. Swift trigger 1418333 is not an astrophysical source
  52. GRB 251128A: Fermi GBM Observation
  53. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  54. GRB 251126A: Swift-BAT refined analysis
  55. GRB 251127A: Glowbug gamma-ray detection
  56. GRB 251126A: OHP/T193 optical observations and tentative spectroscopic redshift
  57. GRB 250702B: detection of the compact radio counterpart 139 days after the burst
  58. GRB 251126A NUTTelA-TAO Early Measurements
  59. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  60. EP251124a: Pan-STARRS ri-band imaging and photometry
  61. GRB 251126A: Swift-XRT refined Analysis
  62. GRB 251126A : MITSuME Akeno optical afterglow candidate 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 251126A: Kilonova-Catcher optical afterglow detection
  66. GRB 251126A: Swift detection of a burst
  67. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  68. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  69. EP251124a: Swift-XRT observations
  70. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  71. EP251124a: Optical upper limit with Kinder observations
  72. EP251118A: 6 GHz VLA Detection
  73. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  74. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  75. GRB 251116C: Swift-XRT confirmation of fading
  76. EP251122a / GRB 251122A: optical counterpart candidate with Kinder observations
  77. GRB 251122A/EP251122a: SVOM/C-GFT upper limit
  78. GRB 251122A / EP251122a: SVOM detection of a long burst
  79. EP251118a: Continued Optical Detection with Kinder observations
  80. LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
  81. GRB 251121A: Glowbug gamma-ray detection of a likely short burst
  82. GRB 251115A: Fermi GBM Observation
  83. GRB 251118A: Swift/UVOT Detection
  84. EP251118a / GRB 251118C: SAO RAS optical observations
  85. GRB 251118A: Glowbug gamma-ray detection
  86. GRB 251118A: Swift-XRT afterglow detection
  87. EP251118a: Optical detection with Kinder observations
  88. EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
  89. GRB 251118C: Glowbug gamma-ray detection of the fast X-ray transient EP251118A
  90. GRB 251117A: Swift-XRT observations
  91. GRB 251118C: SVOM/GRM observation of a possible gamma-ray counterpart of EP251118a
  92. Konus-Wind detection of GRB 251118C (EP251118a)
  93. GRB 251119A: SVOM trigger sb25111901 is not a GRB
  94. EP251118a: GOTO optical afterglow detection
  95. GRB 251118A: Fermi-LAT detection
  96. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  97. GRB 251116C: SVOM/ECLAIRs refined analysis
  98. GRB 251116B: SVOM/ECLAIRs refined analysis
  99. GRB 251117A: AstroSat CZTI detection
  100. GRB 251013C: Koshka, SAO RAS, Mondy, and CrAO optical observations, possible SN detection

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