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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"

32580 results found.

  1. LIGO/Virgo/KAGRA S251103f: Identification of a GW compact binary merger candidate
  2. EP251102a: NIR observations with WINTER
  3. GRB 251103A: J-band detection with WINTER
  4. Swift GRB 251103B: Global MASTER-Net observations report
  5. GRB 251103B: GROWTH-India Telescope optical upper limits
  6. GRB 251103A: Kilonova-Catcher optical afterglow detection
  7. GRB 251103A: Swift/UVOT Detection
  8. GRB 251103A: Fermi GBM Observation
  9. GRB 251103A: SVOM/GRM observation
  10. GRB 251103A: Swift-XRT afterglow detection
  11. LIGO/Virgo/KAGRA S251031cq: Updated Sky localization
  12. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  13. EP251102a: Einstein Probe detection of a fast X-ray transient
  14. GRB 251025B: OHP/T193 optical upper limit
  15. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  16. GRB 251103A: LCO optical observation
  17. GRB 251103A: GOTO optical afterglow detection
  18. GRB 251102A: AstroSat CZTI detection
  19. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart
  20. GRB 251103A: NOT spectroscopic redshift z = 0.76
  21. GRB 251103A: LCO optical afterglow detection
  22. GRB 251103A: NOT optical afterglow candidate (duplicate submission)
  23. GRB 251103A: NOT optical afterglow candidate
  24. Fermi GRB 251102A: Global MASTER-Net observations report
  25. GRB 251031A: Fermi GBM Observation
  26. LIGO/Virgo/KAGRA S251031cq: Identification of a GW compact binary merger candidate
  27. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  28. Konus-Wind detection of GRB 251028A
  29. GRB 251025C: SVOM/GRM observation
  30. GRB 251028A: GECAM-B detection
  31. GRB 251028A: SVOM/GRM observation
  32. IceCube-251025A: Two Transient Candidates from the Zwicky Transient Facility
  33. GRB 251028A: Fermi GBM Observation
  34. GRB 251026B: SOAR Classification of GOTO25jgl/SN2025absf as a Type Ia supernova
  35. GRB 251022A: Swift-XRT confirmation of fading
  36. GRB 251026B: LBT near-infrared observations
  37. GRB 250926B: VZLUSAT-2 detection
  38. GRB 250926A: VZLUSAT-2 detection
  39. GRB 250925A: VZLUSAT-2 detection
  40. GRB 251026A/EP251026a: SVOM/VT optical counterpart
  41. GRB 251026A/EP251026a: EP-FXT follow-up observation
  42. GRB 251028B: Fermi/GBM observation
  43. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  44. GRB 251028B: Glowbug gamma-ray detection
  45. GRB 251028A: Glowbug gamma-ray detection
  46. GRB 251028B: CALET Gamma-Ray Burst Monitor detection
  47. Fermi GRB 251028B: Global MASTER-Net observations report
  48. GRB 251025B: GROWTH-India Telescope continued multiband optical observations and rebrightening
  49. GRB251026B: PRIME H-band upper limit
  50. GRB251025B: 3.6m DOT Optical Observations
  51. SVOM trigger sb25102702/GRB 251027A is not a GRB
  52. IceCube-251025A: Upper limits from a search for additional neutrino events in IceCube
  53. GRB 251025B: Swift-XRT confirmation of fading
  54. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  55. GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
  56. GRB 251025C: Glowbug gamma-ray detection
  57. Fermi-LAT Gamma-ray Observations of IceCube-251025A
  58. GRB 251023B: Swift-UVOT Upper Limits
  59. Konus-Wind detection of GRB 251022A
  60. GRB 251022A: SVOM/GRM observation
  61. GRB 251026B: Swift ToO observations
  62. GRB 251026A/EP251026a: Einstein Probe detection of a fast X-ray transient
  63. GRB 251027A: LCO optical upper limit
  64. GRB 251027A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  65. GRB 251017A: Mondy AZT-33IK and Koshka Zeiss-1000 optical observations
  66. GRB 251023B / EP251023b: Mondy optical upper limit
  67. GRB 251017A: INASAN-Kislovodsk optical observations
  68. GRB 251026A: Mondy optical upper limit
  69. GRB 251025B: Mondy optical observations
  70. GRB 251025B: Kilonova-Catcher optical afterglow detection
  71. Konus-Wind detection of GRB 251016A (short/hard)
  72. GRB 251025B: VLT/MUSE spectroscopic redshift z = 2.003
  73. GRB 251026B: Tentative GOTO optical counterpart candidate
  74. GRB 251025C: AstroSat CZTI detection
  75. EP251023a: Mondy optical observations
  76. GRB 251025C: CALET Gamma-Ray Burst Monitor detection
  77. GRB 251025B: MAO/AZT-22 optical observations
  78. LIGO/Virgo/KAGRA S251026bn: Updated Sky localization
  79. Fermi GRB 251026B: Global MASTER-Net observations report
  80. Fermi GRB 251025C: Global MASTER-Net observations report
  81. LIGO/Virgo/KAGRA S251026bn: Identification of a GW compact binary merger candidate
  82. GRB 251026A: Swift-XRT observations
  83. GRB 251025B: OHP/T193 optical detection
  84. GRB 251025B: J-band detection with WINTER
  85. GRB 251026A: SVOM/C-GFT upper limit
  86. IceCube-251025A: DDOTI Optical Upper Limit
  87. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  88. GRB 251025B: SVOM/VT optical bump
  89. GRB 251025B: SVOM/COLIBRÍ (FM-GFT) strong rebrightening of the optical counterpart
  90. GRB 251023A: SVOM/GRM observation
  91. GRB 251025B: ULL-ASTRO-MASTER optical counterpart detection with IAC80 telescope at Teide Observatory
  92. Konus-Wind detection of GRB 251016B
  93. GRB 251025B: GROWTH-India Telescope optical observations
  94. GRB 251024A: Swift/UVOT Upper Limits
  95. GRB 251025B: Swift-XRT afterglow detection
  96. GRB 251024A: Swift-BAT refined analysis
  97. GRB 251025A (sb25102501): stellar flare confirmed
  98. GRB 251025B: SVOM/VT optical observations with VHF data
  99. GRB 251025B: MASTER OT detection
  100. GRB 251025B: SVOM/C-GFT optical counterpart detection

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