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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"

28233 results found.

  1. EP261023a: Mondy optical upper limit
  2. EP261015a: MAO/AZT-22 optical observations
  3. EP261015a: VLA non-detection
  4. EP261023a: NOT optical counterpart candidate
  5. EP261023a: Einstein Probe detection of an X-ray transient
  6. The EP-WXT trigger 01709321472 is likely a flaring star
  7. IceCube-261020A: Upper limits from a search for additional neutrino events in IceCube
  8. NuSTAR 261020, a 830s hard X-ray transient
  9. EP261015a: GSP multiband optical follow-up observations
  10. GRB 261017A: SVOM/GRM observation
  11. EP261015a: Further optical observations with the 1.3m DFOT
  12. GRB 261020B: AstroSat CZTI detection of a short burst
  13. Fermi-LAT Gamma-ray Observations of IceCube-261020A
  14. EP261015a: AZT-20 Assy-Turgen optical observations
  15. GRB 261020A: Fermi GBM Observation
  16. GRB 261017A: SAO RAS optical upper limit
  17. GRB 260903A
  18. EP261015a: Follow-up with the 1.3m DFOT
  19. EP261015a: Terskol Zeiss-2000 optical upper limit
  20. EP261007b: Further EP-FXT follow-up observations
  21. GRB 261017A: COLIBRÍ optical upper limit
  22. GRB 261020A: MAXI GSC detection
  23. EP261015a: COLIBRÍ optical observations of a rebrightening
  24. GRB 261017A: Possible Swift/UVOT Detection
  25. GRB 261017A: Luminance-band upper limit from a 28cm telescope in Chengde
  26. GRB 261017A: R-band upper limit with the 1.3-m DFOT
  27. GRB 261017A: Swift-BAT refined analysis
  28. EP261015b: NOT Optical Observations
  29. GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
  30. EP261015c: refined analysis of the EP-FXT observation favors a stellar flare interpretation
  31. GRB 261017A : MITSuME Akeno optical upper limits
  32. GRB 261017A: Swift-XRT refined Analysis
  33. GRB 261017A: Nanshan/NEXT optical upper limit
  34. GRB 261017A: Enhanced Swift-XRT position
  35. GRB 261017A: Fermi GBM Observation
  36. GRB 261017A: Swift detection of a burst
  37. EP261015a: Tentative fading of the candidate optical counterpart from the NOT
  38. EP261015b: Refined analysis of EP-FXT observations
  39. EP261015b: J-band upper limit by the SYSU 80cm infrared telescope
  40. EP261015a: refined analysis of EP-FXT observations
  41. EP261015c: J-band upper limit with WINTER
  42. EP261015a: J-band upper limit with WINTER
  43. EP261006a / AT 2026aetp: Optical follow-up with the 1.3-m DFOT
  44. GRB 261011A: 1.3m DFOT optical upper limit
  45. GRB 261010A: Pan-STARRS z-band imaging and upper limit
  46. EP261015a: SVOM/VT optical observation
  47. GRB 261010A: VLA radio observations
  48. EP261015a: COLIBRÍ optical observations
  49. EP261015c: Einstein Probe detection of a fast X-ray transient
  50. EP261015b: Einstein Probe detection of an X-ray transient
  51. EP261015a: Einstein Probe detection of a fast X-ray transient
  52. EP261015a (WXT 11900947714): Possible optical counterpart from NOT and LCO
  53. GRB 261010A: LBT tentative near-infrared detection
  54. GRB 261011A: SAO RAS and AbAO optical observations
  55. GRB 261010A: Glowbug gamma-ray detection
  56. GRB 261008A: SVOM/GRM observation
  57. GRB 261009A: GECAM-B detection of a burst
  58. EP261006a : MeerKAT radio observations.
  59. IceCube-261012A: Upper limits from a search for additional neutrino events in IceCube
  60. GRB 261010A: a short minimum variability timescale and a distinct pulse evolution compatible with a merger origin
  61. Fermi-LAT Gamma-ray Observations of IceCube-261012A
  62. GRB 261010A: J-band upper limit by the SYSU 80cm infrared telescope
  63. GRB 261010A: Swift-XRT refined Analysis
  64. GRB 261011A: Swift-XRT refined Analysis
  65. GRB 261011A: Enhanced Swift-XRT position
  66. GRB 261010A: a Type I-L (merger-driven) GRB candidate
  67. GRB 261011A: Swift-BAT refined analysis
  68. GRB 261010A: 10.4m GTC spectroscopy of the galaxy 2" from the afterglow
  69. MAXI GRB261012.23: Global MASTER-Net observations report
  70. GRB 261011A: REM optical/NIR observations
  71. GRB 261011A: SOAR optical afterglow observations at ~17 hours
  72. EP261006a: 10 GHz VLA observations
  73. GRB 261011A: VLT/X-shooter redshift constraints
  74. GRB 261012A: MAXI GSC detection
  75. GRB 261010A: Swift-BAT refined analysis
  76. GRB 261011A : MITSuME Akeno optical afterglow candidate detection
  77. GRB 261011A: Optical followup from Sichuan South Observatory
  78. GRB 261011A: GMG Optical Observation
  79. GRB 261011A: Liverpool Telescope optical observations
  80. GRB 261011A: J-band observations by the SYSU 80cm infrared telescope
  81. GRB 261010A: NOT confirmation of the optical afterglow
  82. GRB 261010A: Fermi GBM Observation
  83. GRB 261011A: continued LCO optical observations
  84. EP261007b: Global MASTER-Net observations report
  85. GRB 261011A: GROWTH-India Telescope optical observations
  86. GRB 261011A: Luminance-band upper limit from a 28cm telescope in Chengde
  87. Swift GRB 261011A: Global MASTER-Net observations report
  88. GRB 261011A: Optical follow-up observations with Kinder
  89. GRB 261011A: SVOM/C-GFT optical observations
  90. EP261007b: Second EP-FXT follow-up observation and a possible X-ray counterpart to the optical transient
  91. GRB 261011A: LCO optical observations
  92. GRB 261011A: SVOM/VT optical observation from VHF data
  93. GRB 261011A: LCO optical observations
  94. GRB 261011A: TRT optical afterglow detection
  95. GRB 261011A: Swift detection of an unusual burst
  96. GRB 261011A: SVOM detection of a long bright burst
  97. GRB 261010A: Enhanced Swift-XRT position
  98. EP261010a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  99. EP261006a / AT 2026aetp: Luminance-band optical follow-up with small-aperture telescopes
  100. GRB 261010A: Swift detection of a burst

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