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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"

28246 results found.

  1. GRB 260509A: KAIT optical observations
  2. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  3. GRB 260509A: SVOM/VT optical candidate with VHF data
  4. GRB 260509A: LCO optical counterpart detection
  5. GRB 260509A: SVOM detection of a burst
  6. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  7. EP260507a: REM optical/NIR observations
  8. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  9. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  10. EP260507a: COLIBRÍ optical observations
  11. EP260507a: NOT optical observations
  12. EP260507a: further Liverpool Telescope observations
  13. EP260507a: Liverpool Telescope optical upper limits
  14. EP260507a: TRT optical counterpart detection
  15. EP260507a: Kinder optical counterpart candidate
  16. EP260507a: LCO optical counterpart
  17. EP260507a: Einstein Probe detection of an X-ray transient
  18. GRB 260506B: BALROG localization (Fermi Trigger 799765648 / GRB 260506547)
  19. Fermi GRB 260506A: Global MASTER-Net observations report
  20. IceCube Alert 260505A: Global MASTER-Net observations report
  21. GRB 260430B: Glowbug gamma-ray detection
  22. GRB 260421B: radio observation with the VLA
  23. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  24. GRB 260430B: AstroSat CZTI detection of a long burst
  25. GRB 260502A: SVOM/GRM observation of a short GRB
  26. GRB 260503A: SVOM/GRM observation of a GRB
  27. Konus-Wind detection of GRB 260411C
  28. GRB 260504B: REM optical/NIR observations
  29. GRB 260504B: LCO z-band upper limit
  30. SVOM GRB 260504B: MASTER-OAFA optical observations
  31. GRB 260504B: SVOM detection of a short burst
  32. Fermi GRB 260504A: Global MASTER-Net observations report
  33. SVOM/GRM observation of a bright burst from SGR 1E1841-045
  34. GRB 260429B / EP260429a: EP-FXT follow-up observation
  35. EP260502a: Einstein Probe detection of an X-ray transient
  36. GRB 260429A: SVOM/GRM observation of a short burst
  37. SN 2026kid: Optical follow-up with small-aperture telescopes in Spain and China
  38. EP260429a: Global MASTER-Net observations report
  39. EP260430a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  40. GRB 260424B: AstroSat CZTI detection
  41. GRB 260429B / EP260429a: COLIBRÍ optical upper limit
  42. EP260429a: LCO optical upper limits
  43. EP260430a: LCO optical upper limits
  44. GRB 260430A / EP260430a: COLIBRÍ optical upper limit
  45. GRB 260429A: Fermi GBM Detection
  46. Fermi GRB 260429A: Global MASTER-Net observations report
  47. EP260430a: Global MASTER-Net observations report
  48. EP260430a: Einstein Probe detection of an X-ray transient
  49. EP260429a: EP-WXT detection of a fast X-ray transient
  50. GRB 260428A: SVOM/GRM observation of a possible short burst with extended emission
  51. IceCube-260425A: Upper limits from a search for additional neutrino events in IceCube
  52. Fermi GRB 260428A: Global MASTER-Net observations report
  53. EP260416a: Mondy and Terskol optical upper limits
  54. GRB 260424B: Glowbug gamma-ray detection of a short burst
  55. GRB 260424B: COLIBRÍ optical upper limit
  56. Fermi-LAT Gamma-ray Observations of IceCube-260425A
  57. GRB 260305A: likely detection by Fermi-LAT and the LAT gamma-ray position
  58. IceCube Alert 260425A: Global MASTER-Net observations report
  59. Fermi trigger No 798737427: Global MASTER-Net observations report
  60. GRB 260401A: cubesat Avion detection
  61. EP260321a: Upper limits from ATCA radio observations
  62. GRB 260421B: Kilonova-Catcher optical afterglow detection
  63. The EP-WXT trigger 01709258652: Mondy optical observations
  64. EP260416a: Mondy optical observations
  65. GRB 260421B: 3.6m DOT optical observation
  66. EP260416a: ZTSh R band observations
  67. IceCube-Cascade 260418A: Upper limits from a search for additional neutrino events in IceCube
  68. GRB 260421B: SVOM/GRM observation
  69. GRB260421B: J band upper limit by SYSU 80cm infrared telescope
  70. GRB 260421B: EP-FXT follow-up observation
  71. GOTO26djh/AT2026jpw: ATCA radio detection
  72. GRB 260421B: J-band upper limit with WINTER
  73. GRB 260421B: LCO optical counterpart detection
  74. GRB 260421B: Fermi GBM Observation
  75. GOTO26djh/AT2026jpw: radio detection at 15GHz
  76. GRB 260421B: SVOM/VT optical observations
  77. EP260416a: J band upper limit by SYSU 80cm infrared telescope
  78. GRB 260310A: Late-time Chandra X-ray Detection
  79. EP260416a: 1.3m DFOT optical observation
  80. Fermi GRB 260421C: Global MASTER-Net observations report
  81. GRB 260421B: VLT/X-shooter spectroscopic redshift z = 2.115
  82. Fermi GRB 260421B: Global MASTER-Net observations report
  83. GRB 260421B: LCO optical afterglow confirmation
  84. GRB 260421B: SVOM/COLIBRÍ (FM-GFT) optical detection of a candidate counterpart
  85. GRB 260421B: TRT optical counterpart detection
  86. GRB 260421B: SVOM detection of a long burst
  87. GRB 260421B: BALROG localization (Fermi Trigger 798437606 / GRB 260421176)
  88. Fermi GRB 260421A: Global MASTER-Net observations report
  89. EP260321a: VLA radio follow-up
  90. GRB 260412A: LCOGT Optical Upper Limits
  91. EP260416a: Optical follow-up observations with Kinder
  92. GOTO26djh/AT2026jpw: CrAO and Mondy optical observations of the transient
  93. GRB 260417A: SVOM/GRM observation
  94. EP260321A/AT2026gzf: Optical observation from 1.3m DFOT
  95. Fermi trigger No 798275385: Global MASTER-Net observations report
  96. EP260417a: GROWTH-India Telescope optical upper limit
  97. Fermi GRB 260417B: Global MASTER-Net observations report
  98. EP260417b: GROWTH-India Telescope optical upper limit
  99. EP260416a: Ondrejov D50 optical detection
  100. EP260417a: Global MASTER-Net observations report

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