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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

23410 results found.

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

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