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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"

28258 results found.

  1. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  2. EP251102a: Einstein Probe detection of a fast X-ray transient
  3. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  4. GRB 251103A: LCO optical observation
  5. EP251102.890: COLIBRÍ optical counterpart candidate
  6. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart
  7. GRB 251103A: LCO optical afterglow detection
  8. GRB 251103A: NOT optical afterglow candidate
  9. GRB 251031A: Fermi GBM Observation
  10. LIGO/Virgo/KAGRA S251031cq: Identification of a GW compact binary merger candidate
  11. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  12. GRB 251031A: BALROG localization (Fermi Trigger 783588065 / GRB 251031306)
  13. GRB 251025C: SVOM/GRM observation
  14. GRB 251028A: SVOM/GRM observation
  15. GRB 251028A: Fermi GBM Observation
  16. GRB 251022A: Swift-XRT confirmation of fading
  17. GRB 250926A: VZLUSAT-2 detection
  18. GRB 251026B: Fermi GBM Observation
  19. GRB 251026A/EP251026a: SVOM/VT optical counterpart
  20. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  21. GRB 251028B: Glowbug gamma-ray detection
  22. GRB 251028A: Glowbug gamma-ray detection
  23. GRB 251025B: GROWTH-India Telescope continued multiband optical observations and rebrightening
  24. GRB251026B: PRIME H-band upper limit
  25. GRB251025B: 3.6m DOT Optical Observations
  26. GRB 251028A: BALROG localization (Fermi Trigger 783314796 / GRB 251028143)
  27. GRB 251028A: MAXI/GSC detection
  28. SVOM trigger sb25102702/GRB 251027A is not a GRB
  29. IceCube-251025A: Upper limits from a search for additional neutrino events in IceCube
  30. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  31. GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
  32. GRB 251025C: Glowbug gamma-ray detection
  33. Fermi-LAT Gamma-ray Observations of IceCube-251025A
  34. GRB 251027A: Swift-XRT observations
  35. EP251027.145: COLIBRÍ optical upper limits
  36. GRB 251022A: SVOM/GRM observation
  37. GRB 251026A/EP251026a: Einstein Probe detection of a fast X-ray transient
  38. GRB 251027A: LCO optical upper limit
  39. GRB 251027A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  40. GRB 251017A: Mondy AZT-33IK and Koshka Zeiss-1000 optical observations
  41. GRB 251023B / EP251023b: Mondy optical upper limit
  42. GRB 251017A: INASAN-Kislovodsk optical observations
  43. GRB 251026A: Mondy optical upper limit
  44. GRB 251025B: Mondy optical observations
  45. GRB 251025B: Kilonova-Catcher optical afterglow detection
  46. GRB 251025B: VLT/MUSE spectroscopic redshift z = 2.003
  47. GRB 251027A: SVOM detection of a faint burst
  48. EP251023a: Mondy optical observations
  49. GRB 251025B: MAO/AZT-22 optical observations
  50. LIGO/Virgo/KAGRA S251026bn: Updated Sky localization
  51. Fermi GRB 251025C: Global MASTER-Net observations report
  52. LIGO/Virgo/KAGRA S251026bn: Identification of a GW compact binary merger candidate
  53. GRB 251026A: Swift-XRT observations
  54. GRB 251025B: OHP/T193 optical detection
  55. GRB 251025B: J-band detection with WINTER
  56. GRB 251026A: SVOM/C-GFT upper limit
  57. IceCube-251025A: DDOTI Optical Upper Limit
  58. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  59. GRB 251026A: SVOM detection of a long burst
  60. GRB 251025B: SVOM/COLIBRÍ (FM-GFT) strong rebrightening of the optical counterpart
  61. GRB 251023A: SVOM/GRM observation
  62. GRB 251025B: ULL-ASTRO-MASTER optical counterpart detection with IAC80 telescope at Teide Observatory
  63. GRB 251025B: GROWTH-India Telescope optical observations
  64. GRB 251024A: Swift/UVOT Upper Limits
  65. GRB 251025B: Swift-XRT afterglow detection
  66. GRB 251024A: Swift-BAT refined analysis
  67. GRB 251024A: Swift-XRT refined Analysis
  68. GRB 251025A (sb25102501): stellar flare confirmed
  69. GRB 251025B: SVOM/VT optical observations with VHF data
  70. GRB 251025B: MASTER OT detection
  71. GRB 251025B: SVOM/C-GFT optical counterpart detection
  72. GRB 251025B: SVOM detection of a burst
  73. GRB 251025A (sb25102501): Likely a stellar flare by SVOM/VT
  74. GRB 251025A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  75. GRB 251025A: SVOM/VT VHF optical upper limit
  76. GRB 251025A: SVOM detection of a faint burst
  77. GRB 251003A: VLA Detection
  78. GRB 251024A: Enhanced Swift-XRT position
  79. GRB 251023C: Glowbug gamma-ray detection
  80. GRB 251024A: LCOGT Optical Afterglow Detection
  81. GRB 251022A: KAIT optical observations
  82. GRB 251024A: Swift detection of a burst
  83. GRB 251023B / EP251023b: COLIBRÍ Confirmation of the Fading Nature of the Optical Candidate
  84. GRB 251022A: COLIBRÍ Further Multi-frequency Optical Observations
  85. EP251023a: MAO/AZT-22 optical observations
  86. GRB 251023C: AstroSat CZTI detection
  87. EP251023b/GRB 251023B: JinShan optical observation
  88. GRB 251022A: Swift-XRT detection of GOTO25iym
  89. EP251023b/GRB 251023B : Einstein Probe detection of a fast X-ray transient
  90. GRB 251022A: GROWTH-India Telescope optical observations
  91. GRB 251023C: Swift/BAT-GUANO localization skymap of a burst
  92. EP251023a: GROWTH-India Telescope optical observations
  93. GRB 251022A: Fermi GBM Observation
  94. GRB 251022A: Swift/BAT-GUANO localization skymap of a burst
  95. GRB 251023A: Glowbug gamma-ray detection
  96. GRB 251023B: Glowbug gamma-ray detection
  97. EP251023a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at Teide Observatory
  98. GRB 251023B / EP#01709247298: COLIBRÍ optical counterpart candidate
  99. IPN triangulation of GRB 251016B
  100. EP#01709247298: Swift-XRT counterpart detection

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