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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"

32690 results found.

  1. EP260429a: Global MASTER-Net observations report
  2. EP260430a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  3. GRB 260424B: AstroSat CZTI detection
  4. GRB 260429B / EP260429a: COLIBRÍ optical upper limit
  5. EP260429a: LCO optical upper limits
  6. EP260430a: LCO optical upper limits
  7. GRB 260430A / EP260430a: COLIBRÍ optical upper limit
  8. Fermi GRB 260429A: Global MASTER-Net observations report
  9. EP260430a: Global MASTER-Net observations report
  10. GRB 260428A: SVOM/GRM observation of a possible short burst with extended emission
  11. GRB 260428A: GECAM-B detection of a possible long duration Type I burst
  12. IceCube-260425A: Upper limits from a search for additional neutrino events in IceCube
  13. GRB 260428A: AstroSat CZTI detection
  14. Fermi GRB 260428A: Global MASTER-Net observations report
  15. EP260416a: Mondy and Terskol optical upper limits
  16. GRB 260424B: Glowbug gamma-ray detection of a short burst
  17. GRB 260424B: COLIBRÍ optical upper limit
  18. Konus-Wind detection of GRB 260424B
  19. Fermi-LAT Gamma-ray Observations of IceCube-260425A
  20. EP260321a/SN 2026gzf: spectroscopy at Mondy observatory
  21. IPN triangulation of GRB 260424B (short)
  22. IceCube-260425A - IceCube observation of a high-energy neutrino candidate track-like event
  23. GRB 260305A: likely detection by Fermi-LAT and the LAT gamma-ray position
  24. GRB 260401A: cubesat Avion detection
  25. EP260321a: Upper limits from ATCA radio observations
  26. GRB 260421B: Kilonova-Catcher optical afterglow detection
  27. GRB 260421B: Insight-HXMT/HE detection
  28. The EP-WXT trigger 01709258652: Mondy optical observations
  29. GRB 250328A: VLT host galaxy discovery and redshift z = 1.250
  30. EP260416a: Mondy optical observations
  31. GRB 260421B: SVOM/ECLAIRs refined analysis
  32. GRB 260421B: 3.6m DOT optical observation
  33. EP260416a: ZTSh R band observations
  34. EP-WXT trigger 01709260362: FRAM-ORM optical observations confirm flaring star G 151-9
  35. EP250512a / GRB 250512B: VLT/X-shooter host galaxy identification and redshift z = 1.773
  36. GRB 250530A: VLT/X-shooter host galaxy redshift z = 1.486
  37. GRB 260419A: AstroSat CZTI detection
  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. GRB 260421A: AstroSat CZTI detection
  46. GOTO26djh/AT2026jpw: radio detection at 15GHz
  47. GRB 260412A: SVOM/ECLAIRs refined analysis
  48. GRB 260421B: SVOM/VT optical observations
  49. EP260416a: J band upper limit by SYSU 80cm infrared telescope
  50. GRB 260310A: Late-time Chandra X-ray Detection
  51. GRB 260418A: Insight-HXMT/HE detection
  52. EP260416a: 1.3m DFOT optical observation
  53. GRB 260415A: CALET Gamma-Ray Burst Monitor detection
  54. GRB 260415B: CALET Gamma-Ray Burst Monitor detection
  55. Fermi GRB 260421C: Global MASTER-Net observations report
  56. GRB 260421B: VLT/X-shooter spectroscopic redshift z = 2.115
  57. Fermi GRB 260421B: Global MASTER-Net observations report
  58. GRB 260421B: BOOTES-7 early optical afterglow detection
  59. GRB 260421B: LCO optical afterglow confirmation
  60. GRB 260421B: SVOM/COLIBRÍ (FM-GFT) optical detection of a candidate counterpart
  61. GRB 260421B: TRT optical counterpart detection
  62. GRB 260421B: SVOM detection of a long burst
  63. Fermi GRB 260421A: Global MASTER-Net observations report
  64. EP260321a: VLA radio follow-up
  65. GRB 260412A: LCOGT Optical Upper Limits
  66. EP260416a: Optical follow-up observations with Kinder
  67. GOTO26djh/AT2026jpw: CrAO and Mondy optical observations of the transient
  68. EP-WXT trigger 01709260303: KAIT optical observations
  69. EP260416a: 1.5m OSN and 2.2m CAHA optical monitoring
  70. GRB 260417A: SVOM/GRM observation
  71. EP260321A/AT2026gzf: Optical observation from 1.3m DFOT
  72. EP260417a: GROWTH-India Telescope optical upper limit
  73. Fermi GRB 260417B: Global MASTER-Net observations report
  74. EP260417b: GROWTH-India Telescope optical upper limit
  75. EP260416a: Ondrejov D50 optical detection
  76. EP260416a: VLT/FORS2 spectroscopic redshift confirmation
  77. EP260417a: Global MASTER-Net observations report
  78. EP260417a/GRB 260417A: refined analysis of the EP-WXT and follow-up EP-FXT observations
  79. EP260416a: NOT tentative spectroscopic redshift of z =1.909
  80. EP260416a: GMG Optical Observation
  81. Fermi GRB 260417A: Global MASTER-Net observations report
  82. Konus-Wind detection of GRB 260411B
  83. GRB 260417A: AstroSat CZTI detection
  84. IPN triangulation of GRB 260411B
  85. EP260416a: LCO observations confirm end of flaring phase
  86. EP260324a / AT2026hir: Further multiband optical follow-up with the PKU 60cm Telescope
  87. EP260417a: TRT optical counterpart detection
  88. EP260416a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  89. EP-WXT trigger 01709259586: KAIT optical observations
  90. EP260416a: KAIT optical upper limit
  91. GRB 260414A: Insight-HXMT/HE detection
  92. EP260416a: COLIBRÍ confirmation of the optical rebrightening
  93. EP260416a: WFST optical observations and rebrightening
  94. GOTO26djh/AT2026jpw: ZTSh R,I bands observations of the transient
  95. EP260416a: SVOM/VT optical observation
  96. GOTO26djh/AT2026jpw: SVOM/VT optical observation
  97. GRB 260415B: Glowbug gamma-ray detection
  98. GRB 260411B: Glowbug gamma-ray detection
  99. GRB 260415A: Insight-HXMT/HE detection
  100. EP260416a: COLIBRÍ optical counterpart candidate

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