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

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