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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"

26667 results found.

  1. EP261015a: VST optical observations
  2. EP261023a: Mondy optical upper limit
  3. EP261015a: MAO/AZT-22 optical observations
  4. EP261015a: VLA non-detection
  5. EP261023a: NOT optical counterpart candidate
  6. EP261023a: Einstein Probe detection of an X-ray transient
  7. The EP-WXT trigger 01709321472 is likely a flaring star
  8. IceCube-261020A: Upper limits from a search for additional neutrino events in IceCube
  9. NuSTAR 261020, a 830s hard X-ray transient
  10. EP261015a: GSP multiband optical follow-up observations
  11. GRB 261017A: SVOM/GRM observation
  12. EP261015a: Further optical observations with the 1.3m DFOT
  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. EP261015a: Follow-up with the 1.3m DFOT
  18. EP261015a: Terskol Zeiss-2000 optical upper limit
  19. EP261007b: Further EP-FXT follow-up observations
  20. GRB 261017A: COLIBRÍ optical upper limit
  21. EP261015a: COLIBRÍ optical observations of a rebrightening
  22. Konus-Wind detection of GRB 261017A
  23. GRB 261017A: Possible Swift/UVOT Detection
  24. GRB 261017A: Luminance-band upper limit from a 28cm telescope in Chengde
  25. GRB 261017A: R-band upper limit with the 1.3-m DFOT
  26. GRB 261017A: a short minimum variability timescale compatible with a compact object merger origin
  27. EP261015b: NOT Optical Observations
  28. GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
  29. EP261015c: refined analysis of the EP-FXT observation favors a stellar flare interpretation
  30. GRB 261017A : MITSuME Akeno optical upper limits
  31. GRB 261017A: Swift-XRT refined Analysis
  32. GRB 261017A: Nanshan/NEXT optical upper limit
  33. GRB 261017A: Enhanced Swift-XRT position
  34. GRB 261017A: Fermi GBM Observation
  35. GRB 261017A: Swift detection of a burst
  36. EP261015a: Tentative fading of the candidate optical counterpart from the NOT
  37. EP261015b: Refined analysis of EP-FXT observations
  38. EP261015b: J-band upper limit by the SYSU 80cm infrared telescope
  39. EP261015a: refined analysis of EP-FXT observations
  40. EP261015c: J-band upper limit with WINTER
  41. EP261015a: J-band upper limit with WINTER
  42. EP261006a / AT 2026aetp: Optical follow-up with the 1.3-m DFOT
  43. GRB 261011A: 1.3m DFOT optical upper limit
  44. GRB 261010A: Pan-STARRS z-band imaging and upper limit
  45. EP261015a: SVOM/VT optical observation
  46. EP241111a and EP250125a: Upper limits from SVOM/GRM Observations
  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. The EP-WXT trigger 01709321333 is likely a flaring star
  54. GRB 261010A: LBT tentative near-infrared detection
  55. GRB 261011A: SAO RAS and AbAO optical observations
  56. GRB 261010A: Glowbug gamma-ray detection
  57. GRB 261008A: SVOM/GRM observation
  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. GRID detection of GRB 261010A
  63. GRB 261010A: J-band upper limit by the SYSU 80cm infrared telescope
  64. GRB 261010A: Swift-XRT refined Analysis
  65. GRB 261011A: Swift-XRT refined Analysis
  66. GRB 261011A: Enhanced Swift-XRT position
  67. GRB 261010A: 10.4m GTC spectroscopy of the galaxy 2" from the afterglow
  68. GRB 261011A: REM optical/NIR observations
  69. Konus-Wind detection of GRB 261010A
  70. Konus-Wind detection of GRB 261011A
  71. Konus-Wind detection of GRB 261007A/EP261007a
  72. GRB 261011A: SOAR optical afterglow observations at ~17 hours
  73. EP261006a: 10 GHz VLA observations
  74. GRB 261011A: VLT/X-shooter redshift constraints
  75. GRB 261011A : MITSuME Akeno optical afterglow candidate detection
  76. GRB 261011A: Optical followup from Sichuan South Observatory
  77. GRB 261011A: GMG Optical Observation
  78. GRB 261011A: Liverpool Telescope optical observations
  79. GRB 261011A: J-band observations by the SYSU 80cm infrared telescope
  80. GRB 261010A: NOT confirmation of the optical afterglow
  81. GRB 261010A: Fermi GBM Observation
  82. GRB 261011A: GROWTH-India Telescope optical observations
  83. GRB 261011A: Luminance-band upper limit from a 28cm telescope in Chengde
  84. GRB 261011A: Optical follow-up observations with Kinder
  85. GRB 261011A: SVOM/C-GFT optical observations
  86. EP261007b: Second EP-FXT follow-up observation and a possible X-ray counterpart to the optical transient
  87. GRB 261011A: LCO optical observations
  88. GRB 261011A: LCO optical observations
  89. GRB 261011A: TRT optical afterglow detection
  90. GRB 261011A: Swift detection of an unusual burst
  91. GRB 261011A: SVOM detection of a long bright burst
  92. GRB 261010A: Enhanced Swift-XRT position
  93. EP261010a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  94. EP261006a / AT 2026aetp: Luminance-band optical follow-up with small-aperture telescopes
  95. GRB 261010A: NOT possible optical counterpart
  96. GRB 261010A: Swift detection of a burst
  97. EP261006a: Kilonova-Catcher optical follow-up and detection
  98. EP261006a / AT 2026aetp: Multiband optical follow-up with the PKU 60cm Telescope
  99. EP261010a: SVOM/VT optical upper limits
  100. EP261006a: Liverpool Telescope optical follow-up

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