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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"

21983 results found.

  1. EP261030a: EP-FXT follow-up observation
  2. EP261030a: GROWTH-India Telescope Upper Limit
  3. EP261030a: Global MASTER-Net observations report
  4. Fermi GRB 261030B: Global MASTER-Net observations report
  5. GRB 261029A: SVOM/ECLAIRs refined analysis
  6. GRB 261029A / AT 2026ahaw: Optical upper limits from the PKU 60cm Telescope
  7. GRB 261026A: Mondy, SAO RAS and Terskol optical observations
  8. GRB 261029A : SVOM/GWAC-F60 observations
  9. EP Alert 261030.22: Global MASTER-Net observations report
  10. GRB 261029A: WFST optical observations
  11. GRB 261029A: ULL-ASTRO-MASTER observations with LCO 1-m telescope at Siding Spring Observatory
  12. GRB 261029A: Ondrejov D50 optical observations, possible rebrightening
  13. GRB 261029A: Liverpool Telescope observations
  14. GRB 261029A: Optical detection with 60cm Panzhihua Telescope
  15. GRB261029A: Infrared fading detected with MDM/MIRAGE
  16. GRB 261029A / AT2026ahaw: r- and i-band optical follow-up with the PKU 60cm Telescope
  17. GRB 261029A: SVOM/C-GFT optical observations
  18. EP261010a: Xinglong optical follow-up
  19. GRB 261029A: LCO optical observations (correction to GCN 46082)
  20. GRB 261029A: SVOM/COLIBRÍ (FM-GFT) optical observations
  21. GRB 261029A: LCO optical observations
  22. GRB 261029A: NOT imaging and spectroscopic redshift z = 3.27
  23. GRB261029A: Early infrared detection with MDM/MIRAGE
  24. GRB 261029A: KAIT optical observations
  25. GRB 261029A: TRT optical observations
  26. EP261006a / AT 2026aetp: Xinglong 2.16-m optical follow-up
  27. EP261025a: EP-FXT follow-up observations
  28. GRB 261029A: GOTO optical counterpart candidate
  29. GRB 261029A: SVOM detection of a burst
  30. GRB 261026A: SVOM/ECLAIRs refined analysis
  31. GRB261026A: Infrared detection with MDM/MIRAGE
  32. GRB 261026A: SVOM/VT optical blue bump
  33. GRB 261026A: SAO RAS optical observations
  34. EP Alert 261026.29: Global MASTER-Net observations report
  35. GRB 261026A: Upper Limit with 60cm Panzhihua Telescope
  36. EP 261025a: J-band upper limit with MIRAGE
  37. GRB 261026A: OHP/T120 optical imaging
  38. GRB 261026A: ULL-ASTRO-MASTER optical detection with LCO 40-cm telescope at Haleakalā Observatory
  39. GRB 261026A: J-band observations by the SYSU 80cm infrared telescope
  40. GRB 261026A: SVOM/VT optical observations
  41. SVOM GRB261026.26: Global MASTER-Net observations report
  42. GRB 261026A: WINTER J-band observations
  43. Fermi GRB 261026B: Global MASTER-Net observations report
  44. GRB 261026A: SVOM/VT optical observation from VHF data
  45. GRB 261026A: KAIT optical observations
  46. GRB 261026A: SVOM/COLIBRÍ (FM-GFT) optical observations
  47. EP261025a: J-band upper limit with WINTER
  48. EP261023a: J-band upper limit with WINTER
  49. EP261025a: Einstein Probe detection of a fast X-ray transient
  50. EP261023a: J band upper limit by SYSU 80cm infrared telescope
  51. EP261015a: VST optical observations
  52. EP261023a: Mondy optical upper limit
  53. EP261015a: MAO/AZT-22 optical observations
  54. EP261015a: VLA non-detection
  55. EP261023a: NOT optical counterpart candidate
  56. NuSTAR 261020, a 830s hard X-ray transient
  57. EP261015a: GSP multiband optical follow-up observations
  58. EP261015a: Further optical observations with the 1.3m DFOT
  59. Fermi-LAT Gamma-ray Observations of IceCube-261020A
  60. EP261015a: AZT-20 Assy-Turgen optical observations
  61. GRB 261017A: SAO RAS optical upper limit
  62. EP261015a: Wendelstein 43 cm optical observations
  63. EP261015a: Follow-up with the 1.3m DFOT
  64. EP261007b: Further EP-FXT follow-up observations
  65. EP261015a: COLIBRÍ optical observations of a rebrightening
  66. GRB 261017A: Possible Swift/UVOT Detection
  67. GRB 261017A: Luminance-band upper limit from a 28cm telescope in Chengde
  68. GRB 261017A: R-band upper limit with the 1.3-m DFOT
  69. EP261015b: NOT Optical Observations
  70. GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
  71. GRB 261017A: Nanshan/NEXT optical upper limit
  72. EP261015a: Tentative fading of the candidate optical counterpart from the NOT
  73. EP261015b: Refined analysis of EP-FXT observations
  74. EP261015b: J-band upper limit by the SYSU 80cm infrared telescope
  75. EP261015a: refined analysis of EP-FXT observations
  76. EP261015c: J-band upper limit with WINTER
  77. EP261015a: J-band upper limit with WINTER
  78. EP261006a / AT 2026aetp: Optical follow-up with the 1.3-m DFOT
  79. GRB 261011A: 1.3m DFOT optical upper limit
  80. GRB 261010A: Pan-STARRS z-band imaging and upper limit
  81. EP241111a and EP250125a: Upper limits from SVOM/GRM Observations
  82. GRB 261010A: VLA radio observations
  83. EP261015a: COLIBRÍ optical observations
  84. EP261015c: Einstein Probe detection of a fast X-ray transient
  85. EP261015b: Einstein Probe detection of an X-ray transient
  86. GRB261010A: Keck/MOSFIRE detection of a near-IR source
  87. EP261015a (WXT 11900947714): Possible optical counterpart from NOT and LCO
  88. GRB 261010A: ASKAP non-detection of a radio afterglow
  89. GRB 261010A: LBT tentative near-infrared detection
  90. GRB 261011A: SAO RAS and AbAO optical observations
  91. EP261006a : MeerKAT radio observations.
  92. GRB 261011A: Later-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  93. Fermi-LAT Gamma-ray Observations of IceCube-261012A
  94. GRB 261010A: J-band upper limit by the SYSU 80cm infrared telescope
  95. IceCube-260919A: No transient candidates from the Zwicky Transient Facility
  96. GRB 261010A: a Type I-L (merger-driven) GRB candidate
  97. GRB 261011A: 10.4m GTC spectroscopic redshift (z = 2.407)
  98. GRB 261010A: 10.4m GTC spectroscopy of the galaxy 2" from the afterglow
  99. MAXI GRB261012.23: Global MASTER-Net observations report
  100. GRB 261011A: REM optical/NIR observations

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