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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"

28229 results found.

  1. EP260416a: Global MASTER-Net observations report
  2. EP260416a: Einstein Probe detection of an X-ray transient
  3. GOTO26djh/AT2026jpw : MASTER OT observation
  4. GOTO26djh/AT2026jpw transient: SAO RAS optical observations
  5. NOT r-band observations of the transient GOTO26djh/AT2026jpw
  6. GRB 260415B: NuSTAR detection of long prompt emission
  7. GOTO discovery of fast-fading transient GOTO26djh/AT2026jpw, a candidate orphan afterglow
  8. Fermi trigger No 797912738: Global MASTER-Net observations report
  9. GRB 260414A: Glowbug gamma-ray detection
  10. EP260409a: Early NIR limits from MIRAGE on the MDM 1.3m telescope
  11. EP260321a: CMO SAI J,K observations
  12. Fermi GRB 260413A: Global MASTER-Net observations report
  13. GRB 260410A: Glowbug gamma-ray detection of a short burst
  14. Fermi GRB 260412A: Global MASTER-Net observations report
  15. GRB 260412A: Fermi GBM Observation
  16. GRB 260411B: Fermi-LAT detection
  17. GRB 260411B: COLIBRÍ optical observations
  18. GRB 260410B: Fermi GBM Observation
  19. GRB260411B: 3.6m DOT optical observation
  20. GRB 260411A: SVOM/GRM observation
  21. GRB 260411B: SVOM/GRM observation of a long burst
  22. GRB 260409A: Insight-HXMT/HE detection
  23. GRB 260411B: Fermi GBM Detection
  24. EP260409a: Gemini/FLAMINGOS2 J-band counterpart
  25. GRB 260411B: BALROG localization (Fermi Trigger 797587480 / GRB 260411337)
  26. GRB 260410A: COLIBRÍ optical upper limit
  27. EP-WXT01709259790: Optical Upper limits with kinder observations
  28. GRB 260410A: Fermi GBM Observation
  29. GRB 260410B: SVOM/GRM detection of a short faint burst
  30. EP-WXT01709259790: Xinglong optical upper limit
  31. EP260409a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  32. GRB 260310A/AT2026fgk: Kilonova-Catcher SN peak identification
  33. EP260409a: COLIBRÍ optical upper limits
  34. EP260409a: Global MASTER-Net observations report
  35. EP260409a: Einstein Probe detection of an X-ray transient
  36. EP260321a: VLA radio detection
  37. GRB 260407A: Glowbug gamma-ray detection
  38. GRB 260402A: SVOM/ECLAIRs refined analysis
  39. GRB 260310A: Continued VLA Multi-frequency Radio Observations
  40. EP260402a / GRB 260402A: Mephisto optical upper limits
  41. EP-WXT01709259586: Xinglong optical upper limit
  42. EP260403a: Mephisto optical upper limits
  43. EP260402a/GRB 260402A: Xinglong optical upper limit
  44. EP260405a: GMOS-N optical upper limits
  45. EP260405a: Global MASTER-Net observations report
  46. EP260405a: Einstein Probe detection of a fast X-ray transient
  47. EP260405a / EP-WXT 11900672904: COLIBRÍ optical upper limits
  48. Fermi trigger No 797039833: Global MASTER-Net observations report
  49. EP260324A / AT 2026hir: COLIBRÍ further optical observations
  50. EP260403a: refined analysis of the EP-WXT and EP-FXT observations
  51. The EP-WXT trigger 01709259586 is likely a flaring star
  52. GRB 260330B: SVOM/VT further optical observation
  53. EP260403a: LCO optical observations of the counterpart
  54. GRB 260310A/AT2026fgk: Kilonova-Catcher long term optical monitoring
  55. EP260403a: LCO optical counterpart detection
  56. EP260403a: COLIBRÍ optical counterpart candidate
  57. GRB 260330B: SVOM/VT optical candidate
  58. EP260403a: Einstein Probe detection of an X-ray transient
  59. GRB 260330B: EP-FXT follow-up and identification of candidate afterglow
  60. EP260402a/GRB 260402A: refined analysis of the EP-WXT and EP-FXT observations
  61. EP260402a/GRB 260402A: Jinshan near-infrared upper limit
  62. GRB 260402C: NuSTAR detection of prompt emission
  63. GRB 260402C: AstroSat CZTI detection of a long burst
  64. EP260324A / AT 2026hir: COLIBRÍ optical observations
  65. GRB 260402A: WINTER J-band upper limit
  66. GRB260402A: GROWTH-India Telescope optical upper limit
  67. GRB 260402A / EP260402a: SVOM/VT optical upper limits
  68. EP260402a/GRB 260402A: SVOM/C-GFT upper limit
  69. GRB 260401A: SVOM/GRM observation
  70. EP260402a/GRB 260402A: Einstein Probe detection of an X-ray transient
  71. GRB 260402A: Kilonova-Catcher optical upper limit
  72. GRB 260402A: MASTER optical observations
  73. GRB 260402A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  74. GRB 260402A: SVOM/MXT candidate X-ray afterglow
  75. GRB 260402A: SVOM detection of a burst
  76. Fermi GRB 260401A: Global MASTER-Net observations report
  77. GRB 260401A: Fermi GBM Observation
  78. GRB 260401A: NuSTAR detection of prompt emission
  79. GRB 260401A: CALET Gamma-Ray Burst Monitor detection
  80. GRB 260401A: MAXI/GSC detection
  81. GRB 260401A: BALROG localization (Fermi Trigger 796733611 / GRB 260401454)
  82. GRB 260401A: Fermi GBM Final Real-time Localization
  83. EP260329b: Mondy and Assy-Turgen optical upper limits
  84. GRB 260310A / AT2026fgk: Luminance-band optical follow-up with a 28cm telescope in Daocheng
  85. EP260321a :Xinglong optical observations
  86. EP260327a: Xinglong optical upper limit
  87. GRB 260330B: SVOM/VT optical upper limits
  88. Konus-Wind detection of GRB 260320A
  89. GRB 260321A: SVOM/ECLAIRs refined analysis
  90. EP260329b: J-band upper limits with WINTER
  91. EP260329a: J-band upper limit with WINTER
  92. GRB 260330A: Glowbug gamma-ray detection
  93. Fermi GBM Sub-Threshold Detection of GRB 260330B
  94. GRB 260330B: LCO optical upper limits
  95. EP260324a / AT2026hir: g- and r-band optical follow-up with the PKU 60cm Telescope
  96. EP260329b: refined analysis of the EP-WXT and EP-FXT observations
  97. EP260329a: COLIBRÍ optical upper limit
  98. EP260329a: EP-FXT follow up observation
  99. EP260329a: NOT optical counterpart candidate
  100. EP260329b: Global MASTER-Net observations report

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