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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"

28232 results found.

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

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