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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"

23566 results found.

  1. EP261025a: J-band upper limit with WINTER
  2. EP261023a: J-band upper limit with WINTER
  3. EP 261025a: COLIBRÍ optical upper limit
  4. EP261025a: Einstein Probe detection of a fast X-ray transient
  5. EP261023a: J band upper limit by SYSU 80cm infrared telescope
  6. EP261015a: VST optical observations
  7. EP261023a: Mondy optical upper limit
  8. EP261015a: MAO/AZT-22 optical observations
  9. EP261015a: VLA non-detection
  10. EP261023a: NOT optical counterpart candidate
  11. EP261023a: Einstein Probe detection of an X-ray transient
  12. NuSTAR 261020, a 830s hard X-ray transient
  13. EP261015a: GSP multiband optical follow-up observations
  14. GRB 261017A: SVOM/GRM observation
  15. EP261015a: Further optical observations with the 1.3m DFOT
  16. EP261015a: AZT-20 Assy-Turgen optical observations
  17. GRB 261017A: SAO RAS optical upper limit
  18. GRB 260903A
  19. EP261015a: Follow-up with the 1.3m DFOT
  20. EP261015a: Terskol Zeiss-2000 optical upper limit
  21. EP261007b: Further EP-FXT follow-up observations
  22. GRB 261017A: COLIBRÍ optical upper limit
  23. EP261015a: COLIBRÍ optical observations of a rebrightening
  24. Konus-Wind detection of GRB 261017A
  25. GRB 261017A: Possible Swift/UVOT Detection
  26. GRB 261017A: Luminance-band upper limit from a 28cm telescope in Chengde
  27. GRB 261017A: R-band upper limit with the 1.3-m DFOT
  28. GRB 261017A: a short minimum variability timescale compatible with a compact object merger origin
  29. EP261015b: NOT Optical Observations
  30. GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
  31. EP261015c: refined analysis of the EP-FXT observation favors a stellar flare interpretation
  32. GRB 261017A : MITSuME Akeno optical upper limits
  33. GRB 261017A: Nanshan/NEXT optical upper limit
  34. GRB 261017A: Enhanced Swift-XRT position
  35. GRB261010A: Retraction of Keck/MOSFIRE near-IR source
  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. EP241111a and EP250125a: Upper limits from SVOM/GRM Observations
  48. GRB 261010A: VLA radio observations
  49. EP261015a: COLIBRÍ optical observations
  50. EP261015c: Einstein Probe detection of a fast X-ray transient
  51. EP261015b: Einstein Probe detection of an X-ray transient
  52. GRB261010A: Keck/MOSFIRE detection of a near-IR source
  53. EP261015a: Einstein Probe detection of a fast X-ray transient
  54. EP261015a (WXT 11900947714): Possible optical counterpart from NOT and LCO
  55. GRB 261010A: ASKAP non-detection of a radio afterglow
  56. GRB 261010A: LBT tentative near-infrared detection
  57. GRB 261011A: SAO RAS and AbAO optical observations
  58. GRB 261010A: Glowbug gamma-ray detection
  59. GRB 261008A: SVOM/GRM observation
  60. EP261006a : MeerKAT radio observations.
  61. GRB 261010A: a short minimum variability timescale and a distinct pulse evolution compatible with a merger origin
  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: 10.4m GTC spectroscopy of the galaxy 2" from the afterglow
  67. GRB 261011A: REM optical/NIR observations
  68. Konus-Wind detection of GRB 261010A
  69. GRB 261011A: SOAR optical afterglow observations at ~17 hours
  70. EP261006a: 10 GHz VLA observations
  71. GRB 261011A: VLT/X-shooter redshift constraints
  72. GRB 261010A: Swift-BAT refined analysis
  73. GRB 261011A : MITSuME Akeno optical afterglow candidate detection
  74. GRB 261011A: Optical followup from Sichuan South Observatory
  75. GRB 261011A: GMG Optical Observation
  76. GRB 261011A: Liverpool Telescope optical observations
  77. GRB 261011A: J-band observations by the SYSU 80cm infrared telescope
  78. GRB 261011A: GROWTH-India Telescope optical observations
  79. GRB 261011A: Luminance-band upper limit from a 28cm telescope in Chengde
  80. GRB 261011A: Optical follow-up observations with Kinder
  81. GRB 261011A: SVOM/C-GFT optical observations
  82. EP261007b: Second EP-FXT follow-up observation and a possible X-ray counterpart to the optical transient
  83. GRB 261011A: LCO optical observations
  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. GRB 261001A: SVOM/GRM observation
  94. EP261006a / AT 2026aetp: Multiband optical follow-up with the PKU 60cm Telescope
  95. EP261010a: SVOM/VT optical upper limits
  96. EP261006a: Liverpool Telescope optical follow-up
  97. EP261010a: NOT optical upper limits
  98. EP261010a Einstein Probe detection of an X-ray transient
  99. EP261006a: Xinglong 2.16m/BFOSC optical follow-up observations
  100. EP261007b: SVOM/ECLAIRs Upper Limit

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