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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"

32721 results found.

  1. GRB 251102B: SVOM/GRM observation
  2. LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
  3. LIGO/Virgo/KAGRA S251105aj: Updated Sky localization
  4. LIGO/Virgo/KAGRA S251103f: Updated Sky localization
  5. IPN triangulation of GRB 251105B (possible sGRB with EE)
  6. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart
  7. GRB 251106A: Swift-XRT afterglow detection
  8. GRB 251106A: Kilonova-Catcher optical upper limit
  9. Fermi GBM Sub-Threshold Detection of GRB 251106A
  10. GRB 251106A: Swift/BAT arcminute localization of a burst
  11. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) detection of a likely optical counterpart
  12. GRB 251106A: MASTER optical observations
  13. GRB 251103B: AstroSat CZTI detection
  14. GRB 251025C: TERI Gamma-ray detection
  15. GRB 251016B: TERI Gamma-ray detection
  16. GRB 251016A: TERI Gamma-ray detection of a short burst
  17. GRB 250920C: TERI Gamma-ray detection
  18. EP251102a: Xinglong 2.16-m clear-band observations of the optical counterpart
  19. GRB 251105A: Fermi GBM Observation
  20. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  21. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  22. GRB 251105B: AstroSat CZTI detection of a short burst with extended emission
  23. GRB 251023A: SVOM/ECLAIRs detection of a burst through targeted search
  24. Fermi GBM Sub-Threshold Detection of GRB 251105B
  25. GRB 251103B: Swift/UVOT Upper Limits
  26. LIGO/Virgo/KAGRA S251105aj: Identification of a GW compact binary merger candidate
  27. Fermi GRB 251105A: Global MASTER-Net observations report
  28. GRB 251103B: Fermi GBM observation
  29. GRB 251028A: Insight-HXMT/HE detection
  30. GRB 251103A: Optical afterglow detection by ZTF’s public survey
  31. EP251102a: FTW optical and NIR observations
  32. GRB 251103A: WFST optical observations
  33. EP251102a: update of EP-FXT follow-up observation
  34. EP251102a: OHP/T193 optical observations
  35. GRB 251103A: OHP/T193 optical observations
  36. GRB 251103A: Xinglong 2.16m optical detection
  37. GRB 251103A: Insight-HXMT detection
  38. GRB 251103A: KAIT optical observations
  39. GRB 251103B: Nanshan/HMT optical upper limit
  40. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  41. GRB 251103B: MITSuME Akeno optical upper limits
  42. Fermi GRB 251103A: Global MASTER-Net observations report
  43. LIGO/Virgo/KAGRA S251103f: Identification of a GW compact binary merger candidate
  44. EP251102a: NIR observations with WINTER
  45. GRB 251103A: J-band detection with WINTER
  46. Swift GRB 251103B: Global MASTER-Net observations report
  47. GRB 251103B: GROWTH-India Telescope optical upper limits
  48. GRB 251103A: Kilonova-Catcher optical afterglow detection
  49. GRB 251103A: Swift/UVOT Detection
  50. GRB 251103A: Fermi GBM Observation
  51. GRB 251103A: SVOM/GRM observation
  52. GRB 251103A: Swift-XRT afterglow detection
  53. LIGO/Virgo/KAGRA S251031cq: Updated Sky localization
  54. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  55. EP251102a: Einstein Probe detection of a fast X-ray transient
  56. GRB 251025B: OHP/T193 optical upper limit
  57. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  58. GRB 251103A: LCO optical observation
  59. GRB 251103A: GOTO optical afterglow detection
  60. GRB 251102A: AstroSat CZTI detection
  61. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart
  62. GRB 251103A: NOT spectroscopic redshift z = 0.76
  63. GRB 251103A: LCO optical afterglow detection
  64. GRB 251103A: NOT optical afterglow candidate (duplicate submission)
  65. GRB 251103A: NOT optical afterglow candidate
  66. Fermi GRB 251102A: Global MASTER-Net observations report
  67. GRB 251031A: Fermi GBM Observation
  68. LIGO/Virgo/KAGRA S251031cq: Identification of a GW compact binary merger candidate
  69. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  70. Konus-Wind detection of GRB 251028A
  71. GRB 251025C: SVOM/GRM observation
  72. GRB 251028A: GECAM-B detection
  73. GRB 251028A: SVOM/GRM observation
  74. IceCube-251025A: Two Transient Candidates from the Zwicky Transient Facility
  75. GRB 251028A: Fermi GBM Observation
  76. GRB 251026B: SOAR Classification of GOTO25jgl/SN2025absf as a Type Ia supernova
  77. GRB 251022A: Swift-XRT confirmation of fading
  78. GRB 251026B: LBT near-infrared observations
  79. GRB 250926B: VZLUSAT-2 detection
  80. GRB 250926A: VZLUSAT-2 detection
  81. GRB 250925A: VZLUSAT-2 detection
  82. GRB 251026A/EP251026a: SVOM/VT optical counterpart
  83. GRB 251026A/EP251026a: EP-FXT follow-up observation
  84. GRB 251028B: Fermi/GBM observation
  85. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  86. GRB 251028B: Glowbug gamma-ray detection
  87. GRB 251028A: Glowbug gamma-ray detection
  88. GRB 251028B: CALET Gamma-Ray Burst Monitor detection
  89. Fermi GRB 251028B: Global MASTER-Net observations report
  90. GRB 251025B: GROWTH-India Telescope continued multiband optical observations and rebrightening
  91. GRB251026B: PRIME H-band upper limit
  92. GRB251025B: 3.6m DOT Optical Observations
  93. SVOM trigger sb25102702/GRB 251027A is not a GRB
  94. IceCube-251025A: Upper limits from a search for additional neutrino events in IceCube
  95. GRB 251025B: Swift-XRT confirmation of fading
  96. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  97. GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
  98. GRB 251025C: Glowbug gamma-ray detection
  99. Fermi-LAT Gamma-ray Observations of IceCube-251025A
  100. GRB 251023B: Swift-UVOT Upper Limits

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