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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"

26509 results found.

  1. GRB 260421B: SVOM/VT optical observations
  2. EP260416a: J band upper limit by SYSU 80cm infrared telescope
  3. GRB 260310A: Late-time Chandra X-ray Detection
  4. GRB 260418A: Insight-HXMT/HE detection
  5. GRB 260415A: CALET Gamma-Ray Burst Monitor detection
  6. GRB 260415B: CALET Gamma-Ray Burst Monitor detection
  7. GRB 260421B: VLT/X-shooter spectroscopic redshift z = 2.115
  8. GRB 260421B: BOOTES-7 early optical afterglow detection
  9. GRB 260421B: LCO optical afterglow confirmation
  10. GRB 260421B: SVOM/COLIBRÍ (FM-GFT) optical detection of a candidate counterpart
  11. GRB 260421B: TRT optical counterpart detection
  12. GRB 260421B: SVOM detection of a long burst
  13. GRB 260412A: LCOGT Optical Upper Limits
  14. GOTO26djh/AT2026jpw: CrAO and Mondy optical observations of the transient
  15. EP260416a: 1.5m OSN and 2.2m CAHA optical monitoring
  16. GRB 260417A: SVOM/GRM observation
  17. EP260321A/AT2026gzf: Optical observation from 1.3m DFOT
  18. EP260417a: GROWTH-India Telescope optical upper limit
  19. EP260417b: GROWTH-India Telescope optical upper limit
  20. EP260416a: VLT/FORS2 spectroscopic redshift confirmation
  21. EP260417a/GRB 260417A: refined analysis of the EP-WXT and follow-up EP-FXT observations
  22. Konus-Wind detection of GRB 260411B
  23. GRB 260417A: AstroSat CZTI detection
  24. IPN triangulation of GRB 260411B
  25. EP260416a: LCO observations confirm end of flaring phase
  26. EP260324a / AT2026hir: Further multiband optical follow-up with the PKU 60cm Telescope
  27. EP260417a: TRT optical counterpart detection
  28. EP260417a: Einstein Probe detection of an X-ray transient
  29. EP260416a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  30. EP260417b: Einstein Probe detection of a fast X-ray transient
  31. EP260416a: KAIT optical upper limit
  32. GRB 260414A: Insight-HXMT/HE detection
  33. EP260416a: COLIBRÍ confirmation of the optical rebrightening
  34. EP260416a: WFST optical observations and rebrightening
  35. EP260416a: SVOM/VT optical observation
  36. GOTO26djh/AT2026jpw: SVOM/VT optical observation
  37. GRB 260415B: Glowbug gamma-ray detection
  38. GRB 260411B: Glowbug gamma-ray detection
  39. GRB 260415A: Insight-HXMT/HE detection
  40. EP260416a: COLIBRÍ optical counterpart candidate
  41. COLIBRI optical observations of the transient GOTO26djh/AT2026jpw
  42. EP260416a: Einstein Probe detection of an X-ray transient
  43. GOTO26djh/AT2026jpw : MASTER OT observation
  44. GRB 260415B: NuSTAR detection of long prompt emission
  45. GOTO discovery of fast-fading transient GOTO26djh/AT2026jpw, a candidate orphan afterglow
  46. GRB 260414A: Glowbug gamma-ray detection
  47. EP260409a: Early NIR limits from MIRAGE on the MDM 1.3m telescope
  48. GRB 260412A: Insight-HXMT/HE detection
  49. GRB 260410A: Glowbug gamma-ray detection of a short burst
  50. GRB 260410B: Insight-HXMT/HE detection
  51. GRB 260410A: Insight-HXMT/HE detection
  52. Konus-Wind detection of GRB 260410A (short/hard)
  53. GRB 260411B: GECAM-B observation of a long burst
  54. EP260321a: SVOM/VT optical observations and color changes around peak
  55. GRB 260410A: CALET Gamma-Ray Burst Monitor detection
  56. GRB 260412A: GECAM-B observation of a long burst
  57. GRB 260412A: Fermi GBM Observation
  58. GRB 260310A / AT2026fgk: NuSTAR detection of the rebrightening
  59. GRB 260411B: Fermi-LAT detection
  60. GRB 260412A: SVOM detection of a long burst
  61. GRB 260411B: COLIBRÍ optical observations
  62. GRB 260410B: Fermi GBM Observation
  63. GRB260411B: 3.6m DOT optical observation
  64. GRB 260411A: SVOM/GRM observation
  65. GRB 260407B: SVOM/GRM detection of a possible magnetar X-ray burst
  66. GRB 260411B: SVOM/GRM observation of a long burst
  67. GRB 260409A: Insight-HXMT/HE detection
  68. GRB 260411B: Fermi GBM Detection
  69. GRB 260411B: GOTO optical counterpart candidate
  70. GRB 260410A: COLIBRÍ optical upper limit
  71. GRB 260410A: Fermi GBM Observation
  72. GRB 260410B: SVOM/GRM detection of a short faint burst
  73. GRB 260410A: Fermi-LAT detection
  74. EP260409a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  75. GRB 260310A/AT2026fgk: Kilonova-Catcher SN peak identification
  76. GRB 260407A: GECAM-A detection
  77. GRB 260407A: Insight-HXMT/HE detection
  78. EP260409a: SVOM/VT optical upper limits
  79. EP260409a: COLIBRÍ optical upper limits
  80. GRB 260407A: CALET Gamma-Ray Burst Monitor detection
  81. EP260409a: Einstein Probe detection of an X-ray transient
  82. GRB 260407A: Glowbug gamma-ray detection
  83. GRB 260402A: SVOM/ECLAIRs refined analysis
  84. GRB 260310A / AT2026fgk: X-ray rebrightening
  85. EP260402a / GRB 260402A: Mephisto optical upper limits
  86. EP260403a: Mephisto optical upper limits
  87. EP260402a/GRB 260402A: Xinglong optical upper limit
  88. EP260321a: Upper limits from VLA radio observations
  89. GRID detection of GRB 260401A
  90. EP260321a: uGMRT observations
  91. EP260405a: SVOM/VT optical upper limits
  92. EP260405a: Einstein Probe detection of a fast X-ray transient
  93. EP260405a / EP-WXT 11900672904: COLIBRÍ optical upper limits
  94. GRB 260403A: GECAM-B observation of a long burst
  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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