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

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