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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"

37588 results found.

  1. GRB 260421B: BOOTES-7 early optical afterglow detection
  2. GRB 260421B: LCO optical afterglow confirmation
  3. GRB 260421B: SVOM/COLIBRÍ (FM-GFT) optical detection of a candidate counterpart
  4. GRB 260421B: TRT optical counterpart detection
  5. GRB 260421B: SVOM detection of a long burst
  6. GRB 260421B: BALROG localization (Fermi Trigger 798437606 / GRB 260421176)
  7. GRB 260421B: Fermi GBM Final Real-time Localization
  8. Fermi GRB 260421A: Global MASTER-Net observations report
  9. GRB 260421A: Fermi GBM Final Real-time Localization
  10. GRB 260412A: LCOGT Optical Upper Limits
  11. GOTO26djh/AT2026jpw: CrAO and Mondy optical observations of the transient
  12. EP-WXT trigger 01709260303: KAIT optical observations
  13. GRB 260417A: SVOM/GRM observation
  14. GRB 260419B: Fermi GBM Final Real-time Localization
  15. GRB 260419A: Fermi GBM Final Real-time Localization
  16. Fermi trigger No 798275385: Global MASTER-Net observations report
  17. Fermi GRB 260417B: Global MASTER-Net observations report
  18. GRB 260418B: Fermi GBM Final Real-time Localization
  19. EP260416a: VLT/FORS2 spectroscopic redshift confirmation
  20. EP260417a/GRB 260417A: refined analysis of the EP-WXT and follow-up EP-FXT observations
  21. GRB 260418A: Fermi GBM Final Real-time Localization
  22. Fermi GRB 260417A: Global MASTER-Net observations report
  23. Konus-Wind detection of GRB 260411B
  24. GRB 260417B: Fermi GBM Final Real-time Localization
  25. GRB 260417A: AstroSat CZTI detection
  26. IPN triangulation of GRB 260411B
  27. EP-WXT trigger 01709259586: KAIT optical observations
  28. EP260416a: KAIT optical upper limit
  29. GRB 260414A: Insight-HXMT/HE detection
  30. GRB 260417A: Fermi GBM Final Real-time Localization
  31. GOTO26djh/AT2026jpw: ZTSh R,I bands observations of the transient
  32. GRB 260415B: Glowbug gamma-ray detection
  33. GRB 260411B: Glowbug gamma-ray detection
  34. GRB 260415A: Insight-HXMT/HE detection
  35. GOTO26djh/AT2026jpw: EP-FXT X-ray counterpart detection
  36. GOTO26djh/AT2026jpw transient: SAO RAS optical observations
  37. GRB 260415B: NuSTAR detection of long prompt emission
  38. GOTO discovery of fast-fading transient GOTO26djh/AT2026jpw, a candidate orphan afterglow
  39. GRB 260415B: Fermi GBM Final Localization
  40. GRB 260415A: Fermi GBM Final Real-time Localization
  41. Fermi trigger No 797912738: Global MASTER-Net observations report
  42. GRB 260414A: Glowbug gamma-ray detection
  43. EP260321a: CMO SAI J,K observations
  44. GRB 260412A: Insight-HXMT/HE detection
  45. GRB 260414A: Fermi GBM Final Real-time Localization
  46. Fermi GRB 260413A: Global MASTER-Net observations report
  47. GRB 260410A: Glowbug gamma-ray detection of a short burst
  48. GRB 260413A: Fermi GBM Final Real-time Localization
  49. GRB 260410B: Insight-HXMT/HE detection
  50. GRB 260410A: Insight-HXMT/HE detection
  51. Konus-Wind detection of GRB 260410A (short/hard)
  52. GRB 260411B: GECAM-B observation of a long burst
  53. GRB 260410A: CALET Gamma-Ray Burst Monitor detection
  54. GRB 260412A: GECAM-B observation of a long burst
  55. Fermi GRB 260412A: Global MASTER-Net observations report
  56. GRB 260412A: Fermi GBM Observation
  57. GRB 260310A / AT2026fgk: NuSTAR detection of the rebrightening
  58. GRB 260411B: Fermi-LAT detection
  59. GRB 260412A: SVOM detection of a long burst
  60. GRB 260412A: Fermi GBM Final Real-time Localization
  61. GRB 260411B: COLIBRÍ optical observations
  62. GRB 260410B: Fermi GBM Observation
  63. GRB 260411B: Ondrejov D50 optical afterglow detection
  64. GRB260411B: 3.6m DOT optical observation
  65. GRB 260411A: SVOM/GRM observation
  66. GRB 260407B: SVOM/GRM detection of a possible magnetar X-ray burst
  67. GRB 260411B: SVOM/GRM observation of a long burst
  68. GRB 260409A: Insight-HXMT/HE detection
  69. GRB 260411B: Fermi GBM Detection
  70. GRB 260411B: GOTO optical counterpart candidate
  71. GRB 260411B: BALROG localization (Fermi Trigger 797587480 / GRB 260411337)
  72. GRB 260411B: Fermi GBM Final Real-time Localization
  73. GRB 260411A: Fermi GBM Final Real-time Localization
  74. GRB 260410A: COLIBRÍ optical upper limit
  75. GRB 260410A: Fermi GBM Observation
  76. GRB 260410B: SVOM/GRM detection of a short faint burst
  77. GRB 260410B: Fermi GBM Final Real-time Localization
  78. GRB 260410A: Fermi-LAT detection
  79. GRB 260410A: Fermi GBM Final Real-time Localization
  80. EP260321a: Chandra X-ray Non-detection
  81. GRB 260409A: Fermi GBM Final Real-time Localization
  82. GRB 260310A/AT2026fgk: Kilonova-Catcher SN peak identification
  83. GRB 260407A: GECAM-A detection
  84. GRB 260407A: Insight-HXMT/HE detection
  85. GRB 260407A: CALET Gamma-Ray Burst Monitor detection
  86. GRB 260404A: Fermi GBM Final Localization
  87. GRB 260407A: Glowbug gamma-ray detection
  88. GRB 260402A: SVOM/ECLAIRs refined analysis
  89. GRB 260310A: Continued VLA Multi-frequency Radio Observations
  90. GRB 260310A / AT2026fgk: X-ray rebrightening
  91. EP260402a / GRB 260402A: Mephisto optical upper limits
  92. EP260402a/GRB 260402A: Xinglong optical upper limit
  93. GRID detection of GRB 260401A
  94. GRB 260407A: Fermi GBM Final Real-time Localization
  95. Fermi trigger No 797039833: Global MASTER-Net observations report
  96. GRB 260403A: GECAM-B observation of a long burst
  97. Fermi Gamma-ray Burst Monitor trigger 796972356/260404217 is not a GRB
  98. GRB 260330B: SVOM/VT further optical observation
  99. Fermi Gamma-ray Burst Monitor trigger 796931884/260403749 is not a GRB
  100. GRB 260330B: SVOM/ECLAIRs refined analysis

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