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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"

28118 results found.

  1. GRB 260504B: SVOM detection of a short burst
  2. Fermi GRB 260504A: Global MASTER-Net observations report
  3. SVOM/GRM observation of a bright burst from SGR 1E1841-045
  4. GRB 260429B / EP260429a: EP-FXT follow-up observation
  5. EP260502a: Einstein Probe detection of an X-ray transient
  6. GRB 260429A: SVOM/GRM observation of a short burst
  7. SN 2026kid: Optical follow-up with small-aperture telescopes in Spain and China
  8. EP260429a: Global MASTER-Net observations report
  9. EP260430a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  10. GRB 260424B: AstroSat CZTI detection
  11. GRB 260429B / EP260429a: COLIBRÍ optical upper limit
  12. EP260429a: LCO optical upper limits
  13. EP260430a: LCO optical upper limits
  14. GRB 260430A / EP260430a: COLIBRÍ optical upper limit
  15. GRB 260429A: Fermi GBM Detection
  16. Fermi GRB 260429A: Global MASTER-Net observations report
  17. EP260430a: Global MASTER-Net observations report
  18. EP260430a: Einstein Probe detection of an X-ray transient
  19. EP260429a: EP-WXT detection of a fast X-ray transient
  20. GRB 260428A: SVOM/GRM observation of a possible short burst with extended emission
  21. IceCube-260425A: Upper limits from a search for additional neutrino events in IceCube
  22. Fermi GRB 260428A: Global MASTER-Net observations report
  23. EP260416a: Mondy and Terskol optical upper limits
  24. GRB 260424B: Glowbug gamma-ray detection of a short burst
  25. GRB 260424B: COLIBRÍ optical upper limit
  26. Fermi-LAT Gamma-ray Observations of IceCube-260425A
  27. GRB 260305A: likely detection by Fermi-LAT and the LAT gamma-ray position
  28. IceCube Alert 260425A: Global MASTER-Net observations report
  29. Fermi trigger No 798737427: Global MASTER-Net observations report
  30. GRB 260401A: cubesat Avion detection
  31. EP260321a: Upper limits from ATCA radio observations
  32. GRB 260421B: Kilonova-Catcher optical afterglow detection
  33. The EP-WXT trigger 01709258652: Mondy optical observations
  34. EP260416a: Mondy optical observations
  35. GRB 260421B: 3.6m DOT optical observation
  36. EP260416a: ZTSh R band observations
  37. IceCube-Cascade 260418A: Upper limits from a search for additional neutrino events in IceCube
  38. GRB 260421B: SVOM/GRM observation
  39. GRB260421B: J band upper limit by SYSU 80cm infrared telescope
  40. GRB 260421B: EP-FXT follow-up observation
  41. GOTO26djh/AT2026jpw: ATCA radio detection
  42. GRB 260421B: J-band upper limit with WINTER
  43. GRB 260421B: LCO optical counterpart detection
  44. GRB 260421B: Fermi GBM Observation
  45. GOTO26djh/AT2026jpw: radio detection at 15GHz
  46. GRB 260421B: SVOM/VT optical observations
  47. EP260416a: J band upper limit by SYSU 80cm infrared telescope
  48. GRB 260310A: Late-time Chandra X-ray Detection
  49. EP260416a: 1.3m DFOT optical observation
  50. Fermi GRB 260421C: Global MASTER-Net observations report
  51. GRB 260421B: VLT/X-shooter spectroscopic redshift z = 2.115
  52. Fermi GRB 260421B: Global MASTER-Net observations report
  53. GRB 260421B: LCO optical afterglow confirmation
  54. GRB 260421B: SVOM/COLIBRÍ (FM-GFT) optical detection of a candidate counterpart
  55. GRB 260421B: TRT optical counterpart detection
  56. GRB 260421B: SVOM detection of a long burst
  57. GRB 260421B: BALROG localization (Fermi Trigger 798437606 / GRB 260421176)
  58. Fermi GRB 260421A: Global MASTER-Net observations report
  59. EP260321a: VLA radio follow-up
  60. GRB 260412A: LCOGT Optical Upper Limits
  61. EP260416a: Optical follow-up observations with Kinder
  62. GOTO26djh/AT2026jpw: CrAO and Mondy optical observations of the transient
  63. GRB 260417A: SVOM/GRM observation
  64. EP260321A/AT2026gzf: Optical observation from 1.3m DFOT
  65. Fermi trigger No 798275385: Global MASTER-Net observations report
  66. EP260417a: GROWTH-India Telescope optical upper limit
  67. Fermi GRB 260417B: Global MASTER-Net observations report
  68. EP260417b: GROWTH-India Telescope optical upper limit
  69. EP260416a: Ondrejov D50 optical detection
  70. EP260417a: Global MASTER-Net observations report
  71. EP260417a/GRB 260417A: refined analysis of the EP-WXT and follow-up EP-FXT observations
  72. EP260416a: GMG Optical Observation
  73. Fermi GRB 260417A: Global MASTER-Net observations report
  74. EP260416a: LCO observations confirm end of flaring phase
  75. EP260324a / AT2026hir: Further multiband optical follow-up with the PKU 60cm Telescope
  76. EP260417a: TRT optical counterpart detection
  77. EP260417a: Einstein Probe detection of an X-ray transient
  78. EP260416a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  79. EP260417b: Einstein Probe detection of a fast X-ray transient
  80. EP260416a: KAIT optical upper limit
  81. EP260416a: COLIBRÍ confirmation of the optical rebrightening
  82. EP260416a: WFST optical observations and rebrightening
  83. GOTO26djh/AT2026jpw: ZTSh R,I bands observations of the transient
  84. GOTO26djh/AT2026jpw: SVOM/VT optical observation
  85. GRB 260415B: Glowbug gamma-ray detection
  86. GRB 260411B: Glowbug gamma-ray detection
  87. EP260416a: COLIBRÍ optical counterpart candidate
  88. COLIBRI optical observations of the transient GOTO26djh/AT2026jpw
  89. EP260416a: Global MASTER-Net observations report
  90. EP260416a: Einstein Probe detection of an X-ray transient
  91. GOTO26djh/AT2026jpw : MASTER OT observation
  92. GOTO26djh/AT2026jpw transient: SAO RAS optical observations
  93. NOT r-band observations of the transient GOTO26djh/AT2026jpw
  94. GRB 260415B: NuSTAR detection of long prompt emission
  95. GOTO discovery of fast-fading transient GOTO26djh/AT2026jpw, a candidate orphan afterglow
  96. Fermi trigger No 797912738: Global MASTER-Net observations report
  97. GRB 260414A: Glowbug gamma-ray detection
  98. EP260409a: Early NIR limits from MIRAGE on the MDM 1.3m telescope
  99. EP260321a: CMO SAI J,K observations
  100. Fermi GRB 260413A: Global MASTER-Net observations report

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