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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"

20501 results found.

  1. GRB 251103A: Swift-XRT afterglow detection
  2. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  3. EP251102a: Einstein Probe detection of a fast X-ray transient
  4. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  5. GRB 251103A: LCO optical observation
  6. EP251102.890: COLIBRÍ optical counterpart candidate
  7. GRB 251102A: AstroSat CZTI detection
  8. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart
  9. GRB 251103A: NOT spectroscopic redshift z = 0.76
  10. GRB 251103A: LCO optical afterglow detection
  11. GRB 251103A: NOT optical afterglow candidate
  12. LIGO/Virgo/KAGRA S251031cq: Identification of a GW compact binary merger candidate
  13. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  14. GRB 251025C: SVOM/GRM observation
  15. GRB 251028A: GECAM-B detection
  16. GRB 251028A: SVOM/GRM observation
  17. GRB 251022A: Swift-XRT confirmation of fading
  18. GRB 251026A/EP251026a: SVOM/VT optical counterpart
  19. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  20. GRB 251025B: GROWTH-India Telescope continued multiband optical observations and rebrightening
  21. GRB251026B: PRIME H-band upper limit
  22. GRB251025B: 3.6m DOT Optical Observations
  23. SVOM trigger sb25102702/GRB 251027A is not a GRB
  24. IceCube-251025A: Upper limits from a search for additional neutrino events in IceCube
  25. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  26. GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
  27. Fermi-LAT Gamma-ray Observations of IceCube-251025A
  28. GRB 251027A: Swift-XRT observations
  29. EP251027.145: COLIBRÍ optical upper limits
  30. GRB 251022A: SVOM/GRM observation
  31. GRB 251026A/EP251026a: Einstein Probe detection of a fast X-ray transient
  32. GRB 251027A: LCO optical upper limit
  33. GRB 251027A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  34. GRB 251023B / EP251023b: Mondy optical upper limit
  35. GRB 251017A: INASAN-Kislovodsk optical observations
  36. GRB 251026A: Mondy optical upper limit
  37. GRB 251025B: Mondy optical observations
  38. GRB 251025B: Kilonova-Catcher optical afterglow detection
  39. GRB 251025B: VLT/MUSE spectroscopic redshift z = 2.003
  40. GRB 251025C: AstroSat CZTI detection
  41. EP251023a: Mondy optical observations
  42. GRB 251025B: MAO/AZT-22 optical observations
  43. LIGO/Virgo/KAGRA S251026bn: Identification of a GW compact binary merger candidate
  44. GRB 251025B: J-band detection with WINTER
  45. GRB 251026A: SVOM/C-GFT upper limit
  46. IceCube-251025A: DDOTI Optical Upper Limit
  47. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  48. GRB 251026A: SVOM detection of a long burst
  49. GRB 251025B: SVOM/COLIBRÍ (FM-GFT) strong rebrightening of the optical counterpart
  50. GRB 251023A: SVOM/GRM observation
  51. GRB 251025B: ULL-ASTRO-MASTER optical counterpart detection with IAC80 telescope at Teide Observatory
  52. GRB 251025B: GROWTH-India Telescope optical observations
  53. GRB 251024A: Swift/UVOT Upper Limits
  54. GRB 251025B: Swift-XRT afterglow detection
  55. GRB 251025A (sb25102501): stellar flare confirmed
  56. GRB 251025B: SVOM/VT optical observations with VHF data
  57. GRB 251025B: MASTER OT detection
  58. GRB 251025B: SVOM/C-GFT optical counterpart detection
  59. GRB 251025B: SVOM detection of a burst
  60. GRB 251025A (sb25102501): Likely a stellar flare by SVOM/VT
  61. GRB 251025A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  62. GRB 251025A: SVOM/VT VHF optical upper limit
  63. GRB 251025A: SVOM detection of a faint burst
  64. GRB 251024A: Enhanced Swift-XRT position
  65. GRB 251024A: LCOGT Optical Afterglow Detection
  66. GRB 251022A: KAIT optical observations
  67. GRB 251024A: Swift detection of a burst
  68. GRB 251023B / EP251023b: COLIBRÍ Confirmation of the Fading Nature of the Optical Candidate
  69. GRB 251022A: COLIBRÍ Further Multi-frequency Optical Observations
  70. EP251023a: MAO/AZT-22 optical observations
  71. EP251023a: OHP/T193 optical observations
  72. EP251023b/GRB 251023B: JinShan optical observation
  73. GRB 251022A: Swift-XRT detection of GOTO25iym
  74. EP251023b/GRB 251023B : Einstein Probe detection of a fast X-ray transient
  75. GRB 251022A: GROWTH-India Telescope optical observations
  76. GRB 251023C: Swift/BAT-GUANO localization skymap of a burst
  77. EP251023a: GROWTH-India Telescope optical observations
  78. GRB 251022A: Swift/BAT-GUANO localization skymap of a burst
  79. EP251023a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at Teide Observatory
  80. GRB 251023B / EP#01709247298: COLIBRÍ optical counterpart candidate
  81. IPN triangulation of GRB 251016B
  82. EP251023a: COLIBRÍ optical observations
  83. GRB 251013C: further SAO RAS optical observations
  84. GRB 251022A: COLIBRÍ optical observations
  85. GRB 251013C: ISON-Castelgrande observatory optical observations
  86. GRB 251022A: MASTER OT detection
  87. GRB 251022A: DDOTI Optical Detection
  88. EP251021b/GRB 251021A: SVOM/VT optical candidate
  89. EP251023a: NOT optical counterpart detection
  90. EP251023a: Einstein Probe detection of an X-ray transient
  91. EP251021b: Einstein Probe detection of a fast X-ray transient
  92. GRB 250911A: MAXI/GSC detection
  93. GRB 251016A: SVOM/ECLAIRs refined analysis
  94. LIGO/Virgo/KAGRA S251021u: Identification of a GW compact binary merger candidate
  95. Fermi-LAT gamma-ray observations of IceCube-251018A
  96. GRB 251017A : RAPAS follow-up observations
  97. IceCube-251018A: Upper limits from a search for additional neutrino events in IceCube
  98. GRB 251017A: COLIBRÍ optical observations of a late plateau
  99. IceCube-251018A: DDOTI Optical Upper Limit
  100. GRB 251018A: Enhanced Swift-XRT position

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