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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"

19693 results found.

  1. GRB 261019A: SVOM/GRM observation
  2. GRB 261026A: KAIT optical observations
  3. GRB 261026A: SVOM/COLIBRÍ (FM-GFT) optical observations
  4. GRB 261026A: SVOM detection of a burst
  5. EP261025a: J-band upper limit with WINTER
  6. EP261023a: J-band upper limit with WINTER
  7. EP 261025a: COLIBRÍ optical upper limit
  8. EP261025a: Einstein Probe detection of a fast X-ray transient
  9. EP261023a: J band upper limit by SYSU 80cm infrared telescope
  10. EP261015a: VST optical observations
  11. EP261023a: Mondy optical upper limit
  12. EP261015a: MAO/AZT-22 optical observations
  13. EP261015a: VLA non-detection
  14. EP261023a: NOT optical counterpart candidate
  15. EP261023a: Einstein Probe detection of an X-ray transient
  16. EP261015a: GSP multiband optical follow-up observations
  17. GRB 261017A: SVOM/GRM observation
  18. EP261015a: Further optical observations with the 1.3m DFOT
  19. GRB 261020B: AstroSat CZTI detection of a short burst
  20. EP261015a: AZT-20 Assy-Turgen optical observations
  21. GRB 261017A: SAO RAS optical upper limit
  22. EP261015a: Follow-up with the 1.3m DFOT
  23. EP261015a: Terskol Zeiss-2000 optical upper limit
  24. EP261007b: Further EP-FXT follow-up observations
  25. GRB 261017A: COLIBRÍ optical upper limit
  26. EP261015a: COLIBRÍ optical observations of a rebrightening
  27. GRB 261017A: Possible Swift/UVOT Detection
  28. GRB 261017A: Luminance-band upper limit from a 28cm telescope in Chengde
  29. GRB 261017A: R-band upper limit with the 1.3-m DFOT
  30. GRB 261017A: a short minimum variability timescale compatible with a compact object merger origin
  31. EP261015b: NOT Optical Observations
  32. GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
  33. EP261015c: refined analysis of the EP-FXT observation favors a stellar flare interpretation
  34. GRB 261017A : MITSuME Akeno optical upper limits
  35. GRB 261017A: Nanshan/NEXT optical upper limit
  36. GRB 261017A: Enhanced Swift-XRT position
  37. GRB 261017A: Swift detection of a burst
  38. EP261015a: Tentative fading of the candidate optical counterpart from the NOT
  39. EP261015b: Refined analysis of EP-FXT observations
  40. EP261015b: J-band upper limit by the SYSU 80cm infrared telescope
  41. EP261015a: refined analysis of EP-FXT observations
  42. EP261015c: J-band upper limit with WINTER
  43. EP261015a: J-band upper limit with WINTER
  44. EP261006a / AT 2026aetp: Optical follow-up with the 1.3-m DFOT
  45. GRB 261011A: 1.3m DFOT optical upper limit
  46. GRB 261010A: Pan-STARRS z-band imaging and upper limit
  47. EP261015a: SVOM/VT optical observation
  48. EP241111a and EP250125a: Upper limits from SVOM/GRM 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. EP261015a: Einstein Probe detection of a fast X-ray transient
  53. EP261015a (WXT 11900947714): Possible optical counterpart from NOT and LCO
  54. GRB 261010A: LBT tentative near-infrared detection
  55. GRB 261011A: SAO RAS and AbAO optical observations
  56. GRB 261008A: SVOM/GRM observation
  57. EP261006a : MeerKAT radio observations.
  58. GRID detection of GRB 261010A
  59. GRB 261010A: J-band upper limit by the SYSU 80cm infrared telescope
  60. GRB 261011A: Swift-XRT refined Analysis
  61. GRB 261011A: Enhanced Swift-XRT position
  62. GRB 261010A: 10.4m GTC spectroscopy of the galaxy 2" from the afterglow
  63. MAXI GRB261012.23: Global MASTER-Net observations report
  64. GRB 261011A: REM optical/NIR observations
  65. Konus-Wind detection of GRB 261007A/EP261007a
  66. GRB 261011A: SOAR optical afterglow observations at ~17 hours
  67. EP261006a: 10 GHz VLA observations
  68. GRB 261011A: VLT/X-shooter redshift constraints
  69. GRB 261011A : MITSuME Akeno optical afterglow candidate detection
  70. GRB 261011A: Optical followup from Sichuan South Observatory
  71. GRB 261011A: GMG Optical Observation
  72. GRB 261011A: Liverpool Telescope optical observations
  73. GRB 261011A: J-band observations by the SYSU 80cm infrared telescope
  74. GRB 261011A: GROWTH-India Telescope optical observations
  75. GRB 261011A: Luminance-band upper limit from a 28cm telescope in Chengde
  76. GRB 261011A: Optical follow-up observations with Kinder
  77. GRB 261011A: SVOM/C-GFT optical observations
  78. EP261007b: Second EP-FXT follow-up observation and a possible X-ray counterpart to the optical transient
  79. GRB 261011A: LCO optical observations
  80. GRB 261011A: LCO optical observations
  81. GRB 261011A: TRT optical afterglow detection
  82. GRB 261011A: Swift detection of an unusual burst
  83. GRB 261011A: SVOM detection of a long bright burst
  84. GRB 261010A: Enhanced Swift-XRT position
  85. EP261010a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  86. EP261006a / AT 2026aetp: Luminance-band optical follow-up with small-aperture telescopes
  87. GRB 261010A: Swift detection of a burst
  88. EP261006a: Kilonova-Catcher optical follow-up and detection
  89. EP261006a / AT 2026aetp: Multiband optical follow-up with the PKU 60cm Telescope
  90. EP261010a: SVOM/VT optical upper limits
  91. EP261006a: Liverpool Telescope optical follow-up
  92. EP261010a: NOT optical upper limits
  93. EP261010a Einstein Probe detection of an X-ray transient
  94. EP261006a: Xinglong 2.16m/BFOSC optical follow-up observations
  95. EP261007b: SVOM/ECLAIRs Upper Limit
  96. EP261006a: Optical follow-up observations with MATCH
  97. EP261007b: J-band upper limit by SYSU 80cm infrared telescope
  98. EP261007b: Refined analysis of the EP-WXT and autonomous EP-FXT observations
  99. GRB 261007A / EP261007a: SVOM/GWAC-F60A/B observations
  100. EP261006a / AT 2026aetp: VLT/X-shooter spectroscopic redshift z = 0.1853

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