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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"

32716 results found.

  1. EP260417b: GROWTH-India Telescope optical upper limit
  2. EP260416a: Ondrejov D50 optical detection
  3. EP260416a: VLT/FORS2 spectroscopic redshift confirmation
  4. EP260417a: Global MASTER-Net observations report
  5. EP260417a/GRB 260417A: refined analysis of the EP-WXT and follow-up EP-FXT observations
  6. EP260416a: NOT tentative spectroscopic redshift of z =1.909
  7. EP260416a: GMG Optical Observation
  8. Fermi GRB 260417A: Global MASTER-Net observations report
  9. Konus-Wind detection of GRB 260411B
  10. GRB 260417A: AstroSat CZTI detection
  11. IPN triangulation of GRB 260411B
  12. EP260416a: LCO observations confirm end of flaring phase
  13. EP260324a / AT2026hir: Further multiband optical follow-up with the PKU 60cm Telescope
  14. EP260417a: TRT optical counterpart detection
  15. EP260416a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  16. EP-WXT trigger 01709259586: KAIT optical observations
  17. EP260416a: KAIT optical upper limit
  18. GRB 260414A: Insight-HXMT/HE detection
  19. EP260416a: COLIBRÍ confirmation of the optical rebrightening
  20. EP260416a: WFST optical observations and rebrightening
  21. GOTO26djh/AT2026jpw: ZTSh R,I bands observations of the transient
  22. EP260416a: SVOM/VT optical observation
  23. GOTO26djh/AT2026jpw: SVOM/VT optical observation
  24. GRB 260415B: Glowbug gamma-ray detection
  25. GRB 260411B: Glowbug gamma-ray detection
  26. GRB 260415A: Insight-HXMT/HE detection
  27. EP260416a: COLIBRÍ optical counterpart candidate
  28. COLIBRI optical observations of the transient GOTO26djh/AT2026jpw
  29. EP260416a: Global MASTER-Net observations report
  30. GOTO26djh/AT2026jpw : MASTER OT observation
  31. GOTO26djh/AT2026jpw: EP-FXT X-ray counterpart detection
  32. GOTO26djh/AT2026jpw transient: SAO RAS optical observations
  33. NOT r-band observations of the transient GOTO26djh/AT2026jpw
  34. GRB 260415B: NuSTAR detection of long prompt emission
  35. GRB 260414A: Glowbug gamma-ray detection
  36. EP260409a: Early NIR limits from MIRAGE on the MDM 1.3m telescope
  37. EP260321a: CMO SAI J,K observations
  38. GRB 260412A: Insight-HXMT/HE detection
  39. Fermi GRB 260413A: Global MASTER-Net observations report
  40. GRB 260410A: Glowbug gamma-ray detection of a short burst
  41. GRB 260410B: Insight-HXMT/HE detection
  42. GRB 260410A: Insight-HXMT/HE detection
  43. Konus-Wind detection of GRB 260410A (short/hard)
  44. GRB 260411B: GECAM-B observation of a long burst
  45. EP260321a: SVOM/VT optical observations and color changes around peak
  46. GRB 260410A: CALET Gamma-Ray Burst Monitor detection
  47. GRB 260412A: GECAM-B observation of a long burst
  48. Fermi GRB 260412A: Global MASTER-Net observations report
  49. GRB 260412A: Fermi GBM Observation
  50. GRB 260310A / AT2026fgk: NuSTAR detection of the rebrightening
  51. GRB 260411B: Fermi-LAT detection
  52. GRB 260412A: SVOM detection of a long burst
  53. GRB 260411B: COLIBRÍ optical observations
  54. GRB 260410B: Fermi GBM Observation
  55. GRB 260411B: Ondrejov D50 optical afterglow detection
  56. GRB260411B: 3.6m DOT optical observation
  57. GRB 260411A: SVOM/GRM observation
  58. GRB 260411B: SVOM/GRM observation of a long burst
  59. GRB 260409A: Insight-HXMT/HE detection
  60. GRB 260411B: Fermi GBM Detection
  61. GRB 260411B: GOTO optical counterpart candidate
  62. EP260409a: Gemini/FLAMINGOS2 J-band counterpart
  63. GRB 260410A: COLIBRÍ optical upper limit
  64. EP-WXT01709259790: Optical Upper limits with kinder observations
  65. GRB 260410A: Fermi GBM Observation
  66. GRB 260410B: SVOM/GRM detection of a short faint burst
  67. GRB 260410A: Fermi-LAT detection
  68. EP260409a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  69. EP260321a: Chandra X-ray Non-detection
  70. GRB 260310A/AT2026fgk: Kilonova-Catcher SN peak identification
  71. GRB 260407A: GECAM-A detection
  72. GRB 260407A: Insight-HXMT/HE detection
  73. EP260409a: SVOM/VT optical upper limits
  74. EP260409a: COLIBRÍ optical upper limits
  75. GRB 260407A: CALET Gamma-Ray Burst Monitor detection
  76. EP260409a: Global MASTER-Net observations report
  77. EP260321a: VLA radio detection
  78. GRB 260407A: Glowbug gamma-ray detection
  79. GRB 260402A: SVOM/ECLAIRs refined analysis
  80. GRB 260310A: Continued VLA Multi-frequency Radio Observations
  81. GRB 260310A / AT2026fgk: X-ray rebrightening
  82. EP260402a / GRB 260402A: Mephisto optical upper limits
  83. EP-WXT01709259586: Xinglong optical upper limit
  84. EP260403a: Mephisto optical upper limits
  85. EP260402a/GRB 260402A: Xinglong optical upper limit
  86. EP260321a: Upper limits from VLA radio observations
  87. GRID detection of GRB 260401A
  88. EP260321a: uGMRT observations
  89. EP260405a: GMOS-N optical upper limits
  90. EP260405a: SVOM/VT optical upper limits
  91. EP260405a: Global MASTER-Net observations report
  92. EP260405a: Einstein Probe detection of a fast X-ray transient
  93. GRB 260403A: GECAM-B observation of a long burst
  94. EP260324A / AT 2026hir: COLIBRÍ further optical observations
  95. EP260403a: refined analysis of the EP-WXT and EP-FXT observations
  96. GRB 260330B: SVOM/VT further optical observation
  97. GRB 260330B: SVOM/ECLAIRs refined analysis
  98. EP260403a: LCO optical observations of the counterpart
  99. GRB 260310A/AT2026fgk: Kilonova-Catcher long term optical monitoring
  100. EP260403a: LCO optical counterpart detection

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