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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"

28096 results found.

  1. Fermi GRB 260428A: Global MASTER-Net observations report
  2. EP260416a: Mondy and Terskol optical upper limits
  3. GRB 260424B: Glowbug gamma-ray detection of a short burst
  4. GRB 260424B: COLIBRÍ optical upper limit
  5. Fermi-LAT Gamma-ray Observations of IceCube-260425A
  6. GRB 260305A: likely detection by Fermi-LAT and the LAT gamma-ray position
  7. IceCube Alert 260425A: Global MASTER-Net observations report
  8. Fermi trigger No 798737427: Global MASTER-Net observations report
  9. GRB 260401A: cubesat Avion detection
  10. EP260321a: Upper limits from ATCA radio observations
  11. GRB 260421B: Kilonova-Catcher optical afterglow detection
  12. The EP-WXT trigger 01709258652: Mondy optical observations
  13. EP260416a: Mondy optical observations
  14. GRB 260421B: 3.6m DOT optical observation
  15. EP260416a: ZTSh R band observations
  16. IceCube-Cascade 260418A: Upper limits from a search for additional neutrino events in IceCube
  17. GRB 260421B: SVOM/GRM observation
  18. GRB260421B: J band upper limit by SYSU 80cm infrared telescope
  19. GRB 260421B: EP-FXT follow-up observation
  20. GOTO26djh/AT2026jpw: ATCA radio detection
  21. GRB 260421B: J-band upper limit with WINTER
  22. GRB 260421B: LCO optical counterpart detection
  23. GRB 260421B: Fermi GBM Observation
  24. GOTO26djh/AT2026jpw: radio detection at 15GHz
  25. GRB 260421B: SVOM/VT optical observations
  26. EP260416a: J band upper limit by SYSU 80cm infrared telescope
  27. GRB 260310A: Late-time Chandra X-ray Detection
  28. EP260416a: 1.3m DFOT optical observation
  29. Fermi GRB 260421C: Global MASTER-Net observations report
  30. GRB 260421B: VLT/X-shooter spectroscopic redshift z = 2.115
  31. Fermi GRB 260421B: Global MASTER-Net observations report
  32. GRB 260421B: LCO optical afterglow confirmation
  33. GRB 260421B: SVOM/COLIBRÍ (FM-GFT) optical detection of a candidate counterpart
  34. GRB 260421B: TRT optical counterpart detection
  35. GRB 260421B: SVOM detection of a long burst
  36. GRB 260421B: BALROG localization (Fermi Trigger 798437606 / GRB 260421176)
  37. Fermi GRB 260421A: Global MASTER-Net observations report
  38. EP260321a: VLA radio follow-up
  39. GRB 260412A: LCOGT Optical Upper Limits
  40. EP260416a: Optical follow-up observations with Kinder
  41. GOTO26djh/AT2026jpw: CrAO and Mondy optical observations of the transient
  42. GRB 260417A: SVOM/GRM observation
  43. EP260321A/AT2026gzf: Optical observation from 1.3m DFOT
  44. Fermi trigger No 798275385: Global MASTER-Net observations report
  45. EP260417a: GROWTH-India Telescope optical upper limit
  46. Fermi GRB 260417B: Global MASTER-Net observations report
  47. EP260417b: GROWTH-India Telescope optical upper limit
  48. EP260416a: Ondrejov D50 optical detection
  49. EP260417a: Global MASTER-Net observations report
  50. EP260417a/GRB 260417A: refined analysis of the EP-WXT and follow-up EP-FXT observations
  51. EP260416a: GMG Optical Observation
  52. Fermi GRB 260417A: Global MASTER-Net observations report
  53. EP260416a: LCO observations confirm end of flaring phase
  54. EP260324a / AT2026hir: Further multiband optical follow-up with the PKU 60cm Telescope
  55. EP260417a: TRT optical counterpart detection
  56. EP260417a: Einstein Probe detection of an X-ray transient
  57. EP260416a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  58. EP260417b: Einstein Probe detection of a fast X-ray transient
  59. EP260416a: KAIT optical upper limit
  60. EP260416a: COLIBRÍ confirmation of the optical rebrightening
  61. EP260416a: WFST optical observations and rebrightening
  62. GOTO26djh/AT2026jpw: ZTSh R,I bands observations of the transient
  63. GOTO26djh/AT2026jpw: SVOM/VT optical observation
  64. GRB 260415B: Glowbug gamma-ray detection
  65. GRB 260411B: Glowbug gamma-ray detection
  66. EP260416a: COLIBRÍ optical counterpart candidate
  67. COLIBRI optical observations of the transient GOTO26djh/AT2026jpw
  68. EP260416a: Global MASTER-Net observations report
  69. EP260416a: Einstein Probe detection of an X-ray transient
  70. GOTO26djh/AT2026jpw : MASTER OT observation
  71. GOTO26djh/AT2026jpw transient: SAO RAS optical observations
  72. NOT r-band observations of the transient GOTO26djh/AT2026jpw
  73. GRB 260415B: NuSTAR detection of long prompt emission
  74. GOTO discovery of fast-fading transient GOTO26djh/AT2026jpw, a candidate orphan afterglow
  75. Fermi trigger No 797912738: Global MASTER-Net observations report
  76. GRB 260414A: Glowbug gamma-ray detection
  77. EP260409a: Early NIR limits from MIRAGE on the MDM 1.3m telescope
  78. EP260321a: CMO SAI J,K observations
  79. Fermi GRB 260413A: Global MASTER-Net observations report
  80. GRB 260410A: Glowbug gamma-ray detection of a short burst
  81. Fermi GRB 260412A: Global MASTER-Net observations report
  82. GRB 260412A: Fermi GBM Observation
  83. GRB 260411B: Fermi-LAT detection
  84. GRB 260411B: COLIBRÍ optical observations
  85. GRB 260410B: Fermi GBM Observation
  86. GRB260411B: 3.6m DOT optical observation
  87. GRB 260411A: SVOM/GRM observation
  88. GRB 260411B: SVOM/GRM observation of a long burst
  89. GRB 260409A: Insight-HXMT/HE detection
  90. GRB 260411B: Fermi GBM Detection
  91. EP260409a: Gemini/FLAMINGOS2 J-band counterpart
  92. GRB 260411B: BALROG localization (Fermi Trigger 797587480 / GRB 260411337)
  93. GRB 260410A: COLIBRÍ optical upper limit
  94. EP-WXT01709259790: Optical Upper limits with kinder observations
  95. GRB 260410A: Fermi GBM Observation
  96. GRB 260410B: SVOM/GRM detection of a short faint burst
  97. EP-WXT01709259790: Xinglong optical upper limit
  98. EP260409a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  99. GRB 260310A/AT2026fgk: Kilonova-Catcher SN peak identification
  100. EP260409a: COLIBRÍ optical upper limits

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