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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"

28223 results found.

  1. GRB 261017A: SVOM/GRM observation
  2. EP261015a: Further optical observations with the 1.3m DFOT
  3. GRB 261020B: AstroSat CZTI detection of a short burst
  4. Fermi-LAT Gamma-ray Observations of IceCube-261020A
  5. EP261015a: AZT-20 Assy-Turgen optical observations
  6. GRB 261020A: Fermi GBM Observation
  7. GRB 261017A: SAO RAS optical upper limit
  8. GRB 260903A
  9. EP261015a: Follow-up with the 1.3m DFOT
  10. EP261015a: Terskol Zeiss-2000 optical upper limit
  11. EP261007b: Further EP-FXT follow-up observations
  12. GRB 261017A: COLIBRÍ optical upper limit
  13. GRB 261020A: MAXI GSC detection
  14. EP261015a: COLIBRÍ optical observations of a rebrightening
  15. GRB 261017A: Possible Swift/UVOT Detection
  16. GRB 261017A: Luminance-band upper limit from a 28cm telescope in Chengde
  17. GRB 261017A: R-band upper limit with the 1.3-m DFOT
  18. GRB 261017A: Swift-BAT refined analysis
  19. EP261015b: NOT Optical Observations
  20. GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
  21. EP261015c: refined analysis of the EP-FXT observation favors a stellar flare interpretation
  22. GRB 261017A : MITSuME Akeno optical upper limits
  23. GRB 261017A: Swift-XRT refined Analysis
  24. GRB 261017A: Nanshan/NEXT optical upper limit
  25. GRB 261017A: Enhanced Swift-XRT position
  26. GRB 261017A: Fermi GBM Observation
  27. GRB 261017A: Swift detection of a burst
  28. EP261015a: Tentative fading of the candidate optical counterpart from the NOT
  29. EP261015b: Refined analysis of EP-FXT observations
  30. EP261015b: J-band upper limit by the SYSU 80cm infrared telescope
  31. EP261015a: refined analysis of EP-FXT observations
  32. EP261015c: J-band upper limit with WINTER
  33. EP261015a: J-band upper limit with WINTER
  34. EP261006a / AT 2026aetp: Optical follow-up with the 1.3-m DFOT
  35. GRB 261011A: 1.3m DFOT optical upper limit
  36. GRB 261010A: Pan-STARRS z-band imaging and upper limit
  37. EP261015a: SVOM/VT optical observation
  38. GRB 261010A: VLA radio observations
  39. EP261015a: COLIBRÍ optical observations
  40. EP261015c: Einstein Probe detection of a fast X-ray transient
  41. EP261015b: Einstein Probe detection of an X-ray transient
  42. EP261015a: Einstein Probe detection of a fast X-ray transient
  43. EP261015a (WXT 11900947714): Possible optical counterpart from NOT and LCO
  44. GRB 261010A: LBT tentative near-infrared detection
  45. GRB 261011A: SAO RAS and AbAO optical observations
  46. GRB 261010A: Glowbug gamma-ray detection
  47. GRB 261008A: SVOM/GRM observation
  48. GRB 261009A: GECAM-B detection of a burst
  49. EP261006a : MeerKAT radio observations.
  50. IceCube-261012A: Upper limits from a search for additional neutrino events in IceCube
  51. GRB 261010A: a short minimum variability timescale and a distinct pulse evolution compatible with a merger origin
  52. Fermi-LAT Gamma-ray Observations of IceCube-261012A
  53. GRB 261010A: J-band upper limit by the SYSU 80cm infrared telescope
  54. GRB 261010A: Swift-XRT refined Analysis
  55. GRB 261011A: Swift-XRT refined Analysis
  56. GRB 261011A: Enhanced Swift-XRT position
  57. GRB 261010A: a Type I-L (merger-driven) GRB candidate
  58. GRB 261011A: Swift-BAT refined analysis
  59. GRB 261010A: 10.4m GTC spectroscopy of the galaxy 2" from the afterglow
  60. MAXI GRB261012.23: Global MASTER-Net observations report
  61. GRB 261011A: REM optical/NIR observations
  62. GRB 261011A: SOAR optical afterglow observations at ~17 hours
  63. EP261006a: 10 GHz VLA observations
  64. GRB 261011A: VLT/X-shooter redshift constraints
  65. GRB 261012A: MAXI GSC detection
  66. GRB 261010A: Swift-BAT refined analysis
  67. GRB 261011A : MITSuME Akeno optical afterglow candidate detection
  68. GRB 261011A: Optical followup from Sichuan South Observatory
  69. GRB 261011A: GMG Optical Observation
  70. GRB 261011A: Liverpool Telescope optical observations
  71. GRB 261011A: J-band observations by the SYSU 80cm infrared telescope
  72. GRB 261010A: NOT confirmation of the optical afterglow
  73. GRB 261010A: Fermi GBM Observation
  74. GRB 261011A: continued LCO optical observations
  75. EP261007b: Global MASTER-Net observations report
  76. GRB 261011A: GROWTH-India Telescope optical observations
  77. GRB 261011A: Luminance-band upper limit from a 28cm telescope in Chengde
  78. Swift GRB 261011A: Global MASTER-Net observations report
  79. GRB 261011A: Optical follow-up observations with Kinder
  80. GRB 261011A: SVOM/C-GFT optical observations
  81. EP261007b: Second EP-FXT follow-up observation and a possible X-ray counterpart to the optical transient
  82. GRB 261011A: LCO optical observations
  83. GRB 261011A: SVOM/VT optical observation from VHF data
  84. GRB 261011A: LCO optical observations
  85. GRB 261011A: TRT optical afterglow detection
  86. GRB 261011A: Swift detection of an unusual burst
  87. GRB 261011A: SVOM detection of a long bright burst
  88. GRB 261010A: Enhanced Swift-XRT position
  89. EP261010a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  90. EP261006a / AT 2026aetp: Luminance-band optical follow-up with small-aperture telescopes
  91. GRB 261010A: Swift detection of a burst
  92. EP261006a: Kilonova-Catcher optical follow-up and detection
  93. EP261006a / AT 2026aetp: Multiband optical follow-up with the PKU 60cm Telescope
  94. EP261010a: SVOM/VT optical upper limits
  95. EP261006a: Liverpool Telescope optical follow-up
  96. EP261010a: NOT optical upper limits
  97. EP261010a: Global MASTER-Net observations report
  98. EP261010a Einstein Probe detection of an X-ray transient
  99. GRB261007A: Lesedi optical afterglow detection
  100. EP261006a: Xinglong 2.16m/BFOSC optical follow-up observations

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