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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"

21896 results found.

  1. EP261015a: Follow-up with the 1.3m DFOT
  2. EP261015a: Terskol Zeiss-2000 optical upper limit
  3. EP261007b: Further EP-FXT follow-up observations
  4. GRB 261017A: COLIBRÍ optical upper limit
  5. EP261015a: COLIBRÍ optical observations of a rebrightening
  6. Konus-Wind detection of GRB 261017A
  7. GRB 261017A: Possible Swift/UVOT Detection
  8. GRB 261017A: Luminance-band upper limit from a 28cm telescope in Chengde
  9. GRB 261017A: R-band upper limit with the 1.3-m DFOT
  10. GRB 261017A: a short minimum variability timescale compatible with a compact object merger origin
  11. EP261015b: NOT Optical Observations
  12. GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
  13. EP261015c: refined analysis of the EP-FXT observation favors a stellar flare interpretation
  14. GRB 261017A : MITSuME Akeno optical upper limits
  15. GRB 261017A: Nanshan/NEXT optical upper limit
  16. GRB 261017A: Enhanced Swift-XRT position
  17. GRB 261017A: Swift detection of a burst
  18. EP261015a: Tentative fading of the candidate optical counterpart from the NOT
  19. EP261015b: Refined analysis of EP-FXT observations
  20. EP261015b: J-band upper limit by the SYSU 80cm infrared telescope
  21. EP261015a: refined analysis of EP-FXT observations
  22. EP261015c: J-band upper limit with WINTER
  23. EP261015a: J-band upper limit with WINTER
  24. EP261006a / AT 2026aetp: Optical follow-up with the 1.3-m DFOT
  25. GRB 261011A: 1.3m DFOT optical upper limit
  26. GRB 261010A: Pan-STARRS z-band imaging and upper limit
  27. EP261015a: SVOM/VT optical observation
  28. EP261015a: COLIBRÍ optical observations
  29. EP261015c: Einstein Probe detection of a fast X-ray transient
  30. EP261015b: Einstein Probe detection of an X-ray transient
  31. EP261015a: Einstein Probe detection of a fast X-ray transient
  32. EP261015a (WXT 11900947714): Possible optical counterpart from NOT and LCO
  33. GRB 261010A: LBT tentative near-infrared detection
  34. GRB 261011A: SAO RAS and AbAO optical observations
  35. GRB 261008A: SVOM/GRM observation
  36. EP261006a : MeerKAT radio observations.
  37. GRB 261010A: a short minimum variability timescale and a distinct pulse evolution compatible with a merger origin
  38. GRB 261011A: Later-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  39. GRB 261010A: J-band upper limit by the SYSU 80cm infrared telescope
  40. GRB 261011A: Swift-XRT refined Analysis
  41. GRB 261011A: Enhanced Swift-XRT position
  42. GRB 261010A: 10.4m GTC spectroscopy of the galaxy 2" from the afterglow
  43. GRB 261011A: REM optical/NIR observations
  44. Konus-Wind detection of GRB 261010A
  45. Konus-Wind detection of GRB 261011A
  46. Konus-Wind detection of GRB 261007A/EP261007a
  47. GRB 261011A: SOAR optical afterglow observations at ~17 hours
  48. EP261006a: 10 GHz VLA observations
  49. GRB 261011A: VLT/X-shooter redshift constraints
  50. GRB 261011A : MITSuME Akeno optical afterglow candidate detection
  51. GRB 261011A: Optical followup from Sichuan South Observatory
  52. GRB 261011A: GMG Optical Observation
  53. GRB 261011A: Liverpool Telescope optical observations
  54. GRB 261011A: J-band observations by the SYSU 80cm infrared telescope
  55. GRB 261011A: GROWTH-India Telescope optical observations
  56. GRB 261011A: Luminance-band upper limit from a 28cm telescope in Chengde
  57. GRB 261011A: Optical follow-up observations with Kinder
  58. GRB 261011A: SVOM/C-GFT optical observations
  59. EP261007b: Second EP-FXT follow-up observation and a possible X-ray counterpart to the optical transient
  60. GRB 261011A: LCO optical observations
  61. GRB 261011A: LCO optical observations
  62. GRB 261011A: TRT optical afterglow detection
  63. GRB 261011A: GOTO optical counterpart detection
  64. GRB 261011A: Swift detection of an unusual burst
  65. GRB 261011A: SVOM detection of a long bright burst
  66. GRB 261010A: Enhanced Swift-XRT position
  67. EP261010a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  68. EP261006a / AT 2026aetp: Luminance-band optical follow-up with small-aperture telescopes
  69. GRB 261010A: Swift detection of a burst
  70. EP261006a: Kilonova-Catcher optical follow-up and detection
  71. EP261006a / AT 2026aetp: Multiband optical follow-up with the PKU 60cm Telescope
  72. EP261010a: SVOM/VT optical upper limits
  73. EP261006a: Liverpool Telescope optical follow-up
  74. EP261010a: NOT optical upper limits
  75. EP261010a Einstein Probe detection of an X-ray transient
  76. EP261006a: Xinglong 2.16m/BFOSC optical follow-up observations
  77. EP261007b: SVOM/ECLAIRs Upper Limit
  78. EP261007b: J-band upper limit by SYSU 80cm infrared telescope
  79. EP261007b: Refined analysis of the EP-WXT and autonomous EP-FXT observations
  80. GRB 261007A: SVOM/ECLAIRs refined analysis
  81. GRB 261007A / EP261007a: SVOM/GWAC-F60A/B observations
  82. EP261007b: NOT optical observations, variable source outside the FXT region
  83. EP261007b: SVOM/C-GFT optical upper limits
  84. EP261007b: J-band upper limit with WINTER
  85. The EP-WXT trigger 01709321008/EP261007b：Xinglong optical upper limit
  86. GRB 261007A / EP261007a: AstroSat CZTI detection
  87. EP261006a: Swift/XRT detection of the fading X-ray counterpart
  88. EP261007a/GRB 261007A：Xinglong optical observation
  89. GRB 261007A/EP261007a: Optical follow-up observations with Kinder
  90. EP261006a: Optical follow-up observations with Kinder
  91. EP261006a: Liverpool Telescope optical observations
  92. EP261006a: Early Optical Observations by WFST
  93. GRB 261007A / EP261007a: SVOM/VT optical observations
  94. GRB 261007A: Swift-XRT afterglow detection
  95. EP261007b: SVOM/VT optical upper limits
  96. GRB 261007A: SVOM/COLIBRÍ (FM-GFT) optical observations
  97. EP261007b: Einstein Probe detection of an X-ray transient
  98. GRB 261007A / EP261007a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at McDonald Observatory
  99. GRB 261007A: GROWTH-India Telescope optical observations
  100. GRB 261007A / EP261007a: TRT optical observations

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