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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

28034 results found.

  1. EP260809a: OHP/T193 optical observations
  2. GRB260808B: OHP/T193 optical observations
  3. GRB 260808B / EPF_J230056.0+082842: EP-FXT follow-up observation
  4. EP260809a: Einstein Probe detection of an X-ray transient
  5. GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
  6. GRB 260808B: SVOM/VT optical candidate from VHF data
  7. GRB 260808B: SVOM detection of a faint burst
  8. GRB 260808A: BALROG localization (Fermi Trigger 807850307 / GRB 260808119)
  9. Fermi GRB 260808A: Global MASTER-Net observations report
  10. IceCube Alert 260807A: Global MASTER-Net observations report
  11. GRB 260807A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  12. GRB 260807A: SVOM possible detection of a faint burst
  13. EP260806a: COLIBRÍ optical observations
  14. EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  15. EP260806a: SVOM/VT optical observation
  16. EP260806a: Liverpool Telescope observations of the counterpart show a blue colour
  17. EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  18. EP260806a: LCO likely optical counterpart
  19. EP260806a: Einstein Probe detection of an X-ray transient
  20. GRB 260715A: cubesat Avion detection
  21. GRB 260709A: cubesat Avion detection
  22. GRB 260708A: cubesat Avion detection
  23. GRB 260730B: Glowbug gamma-ray detection
  24. GRB 260805C: Glowbug gamma-ray detection
  25. GRB 260805B: Glowbug gamma-ray detection
  26. Fermi GRB 260805A: Global MASTER-Net observations report
  27. GRB 260804A: Glowbug gamma-ray detection
  28. GRB 260805B: BALROG localization (Fermi Trigger 807622617 / GRB 260805484)
  29. IceCube-Cascade 260801A: Upper limits from a search for additional neutrino events in IceCube
  30. GRB 260708A: LCO further optical observations show supernova features
  31. Fermi GRB 260802B: Global MASTER-Net observations report
  32. GRB 260802A / EP J223759.5+521421: EP-FXT follow-up observation
  33. GRB 260802A: SVOM/VT optical upper limits from VHF data
  34. GRB 260802A: LCO optical upper limits
  35. GRB 260802A / EP J223759.5+531421: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  36. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  37. Fermi-LAT Gamma-ray Observations of IceCube-260722A
  38. EP260731a: COLIBRÍ optical upper limit
  39. EP260731a: NOT optical upper limit
  40. GRB 260730B: NuSTAR detection of prompt emission
  41. EP260731a: Einstein Probe detection of an X-ray transient
  42. EP260728a: COLIBRÍ optical upper limit
  43. EP260729a: Einstein Probe detection of an X-ray transient
  44. EP260727a: SAO RAS optical observations
  45. GRB 260727A: AbAO and SAO RAS optical observations
  46. EP260728a: EP-FXT follow-up observation
  47. GRB 260726A: EP-FXT follow-up observations
  48. EP260728a: Einstein Probe detection of a fast X-ray transient
  49. GRB 260726A: Fermi GBM Observation
  50. EP260727a: 1.5m OSN optical counterpart detection
  51. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  52. EP260727a: OHP/T193 optical observations
  53. GRB 260726A: Liverpool Telescope optical observations
  54. GRB 260727A: Liverpool Telescope optical upper limits
  55. EP260727a: Liverpool Telescope confirmation of optical counterpart
  56. EP260727a: Einstein Probe detection of an X-ray transient
  57. The EP-WXT trigger 01709276927 (EP260727a?): NOT likely optical counterpart
  58. GRB 260727A: Glowbug gamma-ray detection
  59. GRB 260726A: J-band upper limit with WINTER
  60. GRB 260727A: J-band upper limit with WINTER
  61. GRB 260727A / SVOM sb26072702: RAPAS optical non-detection
  62. EP260723a: SVOM/ECLAIRs Upper Limit
  63. GRB 260727A: AstroSat CZTI detection
  64. GRB 260727A: Kilonova-Catcher optical upper limit
  65. GRB 260727A: LCO optical upper limits
  66. Fermi GRB 260726A: Global MASTER-Net observations report
  67. GRB 260726A: SVOM detection of a burst
  68. IceCube-260722A: Classification of ZTF26abjbxfs/SN 2026vts as a Type Ia Supernova
  69. EP260723a: further EP-FXT follow-up observation
  70. EP260725a: EP-WXT detection of an X-ray transient
  71. GRB 260616A: cubesat Avion detection
  72. EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
  73. GRB 260602B: cubesat Avion detection
  74. GRB 260601A: cubesat Avion detection
  75. EP260723a: SVOM/VT optical observation
  76. EP260723a: COLIBRÍ optical observations
  77. EP260723a: NOT optical conterpart confirmation
  78. EP260723a: Liverpool Telescope likely optical counterpart
  79. EP260723a: EP-WXT detection of a fast X-ray transient
  80. IceCube-260722A: Upper limits from a search for additional neutrino events in IceCube
  81. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  82. IceCube Alert 260722A: Global MASTER-Net observations report
  83. GRB 260721A: NuSTAR detection of prompt emission
  84. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  85. Fermi trigger No 806104130: Global MASTER-Net observations report
  86. Fermi GRB 260718A: Global MASTER-Net observations report
  87. GRB 260718A: LCO optical upper limits
  88. GRB 260710A: SVOM/GRM observation
  89. GRB 260718A: Fermi GBM Observation
  90. GRB 260718A : GRANDMA and KNC upper limits
  91. GRB 260718A: SVOM/VT optical upper limits
  92. GRB 260718A: SVOM/VT optical upper limits from VHF data
  93. GRB 260714B: SVOM/GRM observation
  94. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  95. GRB 260714B: COLIBRÍ optical counterpart candidate
  96. SVOM sb26071506: Global MASTER-Net observations report
  97. sb26071506: SVOM detection of a X-ray transient
  98. EP260703a: SVOM/ECLAIRs Upper Limit
  99. GRB 260710A: AstroSat CZTI detection
  100. GRB 260714B: Fermi GBM Detection

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