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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"

32692 results found.

  1. GRB 251103A: Optical afterglow detection by ZTF’s public survey
  2. EP251102a: FTW optical and NIR observations
  3. GRB 251103A: WFST optical observations
  4. EP251102a: update of EP-FXT follow-up observation
  5. EP251102a: OHP/T193 optical observations
  6. GRB 251103A: OHP/T193 optical observations
  7. GRB 251103A: Xinglong 2.16m optical detection
  8. GRB 251103A: Insight-HXMT detection
  9. GRB 251103A: KAIT optical observations
  10. GRB 251103B: Nanshan/HMT optical upper limit
  11. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  12. GRB 251103B: MITSuME Akeno optical upper limits
  13. Fermi GRB 251103A: Global MASTER-Net observations report
  14. LIGO/Virgo/KAGRA S251103f: Identification of a GW compact binary merger candidate
  15. EP251102a: NIR observations with WINTER
  16. GRB 251103A: J-band detection with WINTER
  17. Swift GRB 251103B: Global MASTER-Net observations report
  18. GRB 251103B: GROWTH-India Telescope optical upper limits
  19. GRB 251103A: Kilonova-Catcher optical afterglow detection
  20. GRB 251103A: Swift/UVOT Detection
  21. GRB 251103A: Fermi GBM Observation
  22. GRB 251103A: SVOM/GRM observation
  23. GRB 251103A: Swift-XRT afterglow detection
  24. LIGO/Virgo/KAGRA S251031cq: Updated Sky localization
  25. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  26. EP251102a: Einstein Probe detection of a fast X-ray transient
  27. GRB 251025B: OHP/T193 optical upper limit
  28. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  29. GRB 251103A: LCO optical observation
  30. GRB 251103A: GOTO optical afterglow detection
  31. GRB 251102A: AstroSat CZTI detection
  32. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart
  33. GRB 251103A: NOT spectroscopic redshift z = 0.76
  34. GRB 251103A: LCO optical afterglow detection
  35. GRB 251103A: NOT optical afterglow candidate (duplicate submission)
  36. GRB 251103A: NOT optical afterglow candidate
  37. Fermi GRB 251102A: Global MASTER-Net observations report
  38. GRB 251031A: Fermi GBM Observation
  39. LIGO/Virgo/KAGRA S251031cq: Identification of a GW compact binary merger candidate
  40. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  41. Konus-Wind detection of GRB 251028A
  42. GRB 251025C: SVOM/GRM observation
  43. GRB 251028A: GECAM-B detection
  44. GRB 251028A: SVOM/GRM observation
  45. IceCube-251025A: Two Transient Candidates from the Zwicky Transient Facility
  46. GRB 251028A: Fermi GBM Observation
  47. GRB 251026B: SOAR Classification of GOTO25jgl/SN2025absf as a Type Ia supernova
  48. GRB 251022A: Swift-XRT confirmation of fading
  49. GRB 251026B: LBT near-infrared observations
  50. GRB 250926B: VZLUSAT-2 detection
  51. GRB 250926A: VZLUSAT-2 detection
  52. GRB 250925A: VZLUSAT-2 detection
  53. GRB 251026A/EP251026a: SVOM/VT optical counterpart
  54. GRB 251026A/EP251026a: EP-FXT follow-up observation
  55. GRB 251028B: Fermi/GBM observation
  56. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  57. GRB 251028B: Glowbug gamma-ray detection
  58. GRB 251028A: Glowbug gamma-ray detection
  59. GRB 251028B: CALET Gamma-Ray Burst Monitor detection
  60. Fermi GRB 251028B: Global MASTER-Net observations report
  61. GRB 251025B: GROWTH-India Telescope continued multiband optical observations and rebrightening
  62. GRB251026B: PRIME H-band upper limit
  63. GRB251025B: 3.6m DOT Optical Observations
  64. SVOM trigger sb25102702/GRB 251027A is not a GRB
  65. IceCube-251025A: Upper limits from a search for additional neutrino events in IceCube
  66. GRB 251025B: Swift-XRT confirmation of fading
  67. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  68. GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
  69. GRB 251025C: Glowbug gamma-ray detection
  70. Fermi-LAT Gamma-ray Observations of IceCube-251025A
  71. GRB 251023B: Swift-UVOT Upper Limits
  72. Konus-Wind detection of GRB 251022A
  73. GRB 251022A: SVOM/GRM observation
  74. GRB 251026B: Swift ToO observations
  75. GRB 251026A/EP251026a: Einstein Probe detection of a fast X-ray transient
  76. GRB 251027A: LCO optical upper limit
  77. GRB 251027A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  78. GRB 251017A: Mondy AZT-33IK and Koshka Zeiss-1000 optical observations
  79. GRB 251023B / EP251023b: Mondy optical upper limit
  80. GRB 251017A: INASAN-Kislovodsk optical observations
  81. GRB 251026A: Mondy optical upper limit
  82. GRB 251025B: Mondy optical observations
  83. GRB 251025B: Kilonova-Catcher optical afterglow detection
  84. Konus-Wind detection of GRB 251016A (short/hard)
  85. GRB 251025B: VLT/MUSE spectroscopic redshift z = 2.003
  86. GRB 251026B: Tentative GOTO optical counterpart candidate
  87. GRB 251025C: AstroSat CZTI detection
  88. EP251023a: Mondy optical observations
  89. GRB 251025C: CALET Gamma-Ray Burst Monitor detection
  90. GRB 251025B: MAO/AZT-22 optical observations
  91. LIGO/Virgo/KAGRA S251026bn: Updated Sky localization
  92. Fermi GRB 251026B: Global MASTER-Net observations report
  93. Fermi GRB 251025C: Global MASTER-Net observations report
  94. LIGO/Virgo/KAGRA S251026bn: Identification of a GW compact binary merger candidate
  95. GRB 251026A: Swift-XRT observations
  96. GRB 251025B: OHP/T193 optical detection
  97. GRB 251025B: J-band detection with WINTER
  98. GRB 251026A: SVOM/C-GFT upper limit
  99. IceCube-251025A: DDOTI Optical Upper Limit
  100. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) optical upper limit

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