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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"

28231 results found.

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

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