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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').
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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"

26505 results found.

  1. GRB 260415A: CALET Gamma-Ray Burst Monitor detection
  2. GRB 260415B: CALET Gamma-Ray Burst Monitor detection
  3. GRB 260421B: VLT/X-shooter spectroscopic redshift z = 2.115
  4. GRB 260421B: BOOTES-7 early optical afterglow detection
  5. GRB 260421B: LCO optical afterglow confirmation
  6. GRB 260421B: SVOM/COLIBRÍ (FM-GFT) optical detection of a candidate counterpart
  7. GRB 260421B: TRT optical counterpart detection
  8. GRB 260421B: SVOM detection of a long burst
  9. GRB 260412A: LCOGT Optical Upper Limits
  10. GOTO26djh/AT2026jpw: CrAO and Mondy optical observations of the transient
  11. EP260416a: 1.5m OSN and 2.2m CAHA optical monitoring
  12. GRB 260417A: SVOM/GRM observation
  13. EP260321A/AT2026gzf: Optical observation from 1.3m DFOT
  14. EP260417a: GROWTH-India Telescope optical upper limit
  15. EP260417b: GROWTH-India Telescope optical upper limit
  16. EP260416a: VLT/FORS2 spectroscopic redshift confirmation
  17. EP260417a/GRB 260417A: refined analysis of the EP-WXT and follow-up EP-FXT observations
  18. Konus-Wind detection of GRB 260411B
  19. GRB 260417A: AstroSat CZTI detection
  20. IPN triangulation of GRB 260411B
  21. EP260416a: LCO observations confirm end of flaring phase
  22. EP260324a / AT2026hir: Further multiband optical follow-up with the PKU 60cm Telescope
  23. EP260417a: TRT optical counterpart detection
  24. EP260417a: Einstein Probe detection of an X-ray transient
  25. EP260416a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  26. EP260417b: Einstein Probe detection of a fast X-ray transient
  27. EP260416a: KAIT optical upper limit
  28. GRB 260414A: Insight-HXMT/HE detection
  29. EP260416a: COLIBRÍ confirmation of the optical rebrightening
  30. EP260416a: WFST optical observations and rebrightening
  31. EP260416a: SVOM/VT optical observation
  32. GOTO26djh/AT2026jpw: SVOM/VT optical observation
  33. GRB 260415B: Glowbug gamma-ray detection
  34. GRB 260411B: Glowbug gamma-ray detection
  35. GRB 260415A: Insight-HXMT/HE detection
  36. EP260416a: COLIBRÍ optical counterpart candidate
  37. COLIBRI optical observations of the transient GOTO26djh/AT2026jpw
  38. EP260416a: Einstein Probe detection of an X-ray transient
  39. GOTO26djh/AT2026jpw : MASTER OT observation
  40. GRB 260415B: NuSTAR detection of long prompt emission
  41. GOTO discovery of fast-fading transient GOTO26djh/AT2026jpw, a candidate orphan afterglow
  42. GRB 260414A: Glowbug gamma-ray detection
  43. EP260409a: Early NIR limits from MIRAGE on the MDM 1.3m telescope
  44. GRB 260412A: Insight-HXMT/HE detection
  45. GRB 260410A: Glowbug gamma-ray detection of a short burst
  46. GRB 260410B: Insight-HXMT/HE detection
  47. GRB 260410A: Insight-HXMT/HE detection
  48. Konus-Wind detection of GRB 260410A (short/hard)
  49. GRB 260411B: GECAM-B observation of a long burst
  50. EP260321a: SVOM/VT optical observations and color changes around peak
  51. GRB 260410A: CALET Gamma-Ray Burst Monitor detection
  52. GRB 260412A: GECAM-B observation of a long burst
  53. GRB 260412A: Fermi GBM Observation
  54. GRB 260310A / AT2026fgk: NuSTAR detection of the rebrightening
  55. GRB 260411B: Fermi-LAT detection
  56. GRB 260412A: SVOM detection of a long burst
  57. GRB 260411B: COLIBRÍ optical observations
  58. GRB 260410B: Fermi GBM Observation
  59. GRB260411B: 3.6m DOT optical observation
  60. GRB 260411A: SVOM/GRM observation
  61. GRB 260407B: SVOM/GRM detection of a possible magnetar X-ray burst
  62. GRB 260411B: SVOM/GRM observation of a long burst
  63. GRB 260409A: Insight-HXMT/HE detection
  64. GRB 260411B: Fermi GBM Detection
  65. GRB 260411B: GOTO optical counterpart candidate
  66. GRB 260410A: COLIBRÍ optical upper limit
  67. GRB 260410A: Fermi GBM Observation
  68. GRB 260410B: SVOM/GRM detection of a short faint burst
  69. GRB 260410A: Fermi-LAT detection
  70. EP260409a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  71. GRB 260310A/AT2026fgk: Kilonova-Catcher SN peak identification
  72. GRB 260407A: GECAM-A detection
  73. GRB 260407A: Insight-HXMT/HE detection
  74. EP260409a: SVOM/VT optical upper limits
  75. EP260409a: COLIBRÍ optical upper limits
  76. GRB 260407A: CALET Gamma-Ray Burst Monitor detection
  77. EP260409a: Einstein Probe detection of an X-ray transient
  78. GRB 260407A: Glowbug gamma-ray detection
  79. GRB 260402A: SVOM/ECLAIRs refined analysis
  80. GRB 260310A / AT2026fgk: X-ray rebrightening
  81. EP260402a / GRB 260402A: Mephisto optical upper limits
  82. EP260403a: Mephisto optical upper limits
  83. EP260402a/GRB 260402A: Xinglong optical upper limit
  84. EP260321a: Upper limits from VLA radio observations
  85. GRID detection of GRB 260401A
  86. EP260321a: uGMRT observations
  87. EP260405a: SVOM/VT optical upper limits
  88. EP260405a: Einstein Probe detection of a fast X-ray transient
  89. EP260405a / EP-WXT 11900672904: COLIBRÍ optical upper limits
  90. GRB 260403A: GECAM-B observation of a long burst
  91. EP260403a: refined analysis of the EP-WXT and EP-FXT observations
  92. GRB 260330B: SVOM/VT further optical observation
  93. GRB 260330B: SVOM/ECLAIRs refined analysis
  94. EP260403a: LCO optical observations of the counterpart
  95. GRB 260310A/AT2026fgk: Kilonova-Catcher long term optical monitoring
  96. EP260403a: LCO optical counterpart detection
  97. EP260403a: COLIBRÍ optical counterpart candidate
  98. GRB 260330B: SVOM/VT optical candidate
  99. EP260403a: Einstein Probe detection of an X-ray transient
  100. GRB 260330B: EP-FXT follow-up and identification of candidate afterglow

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