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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').
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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"

11755 results found.

  1. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  2. EP260221a: Einstein Probe detection of an X-ray transient
  3. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  4. sb26021801: SVOM detection of a long faint X-ray transient
  5. EP260210a: Mondy optical upper limits
  6. Konus-Wind detection of GRB 260212A
  7. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  8. EP260214b: Optical upper limit with Kinder observations
  9. EP260214a: Optical upper limits with Kinder observations
  10. EP260214b: EP-FXT follow-up observation
  11. EP260214a: COLIBRÍ optical upper limits
  12. EP260214a: refined analysis of the EP-FXT observation
  13. EP260214b: Einstein Probe detection of a fast X-ray transient
  14. EP260214a: Einstein Probe detection of an X-ray transient
  15. GRB 260212A: AstroSat CZTI detection
  16. EP260213a: Optical upper limits with Kinder observations
  17. EP260213a: Mondy R-band optical upper limit
  18. EP260213a: NUTTelA-TAO Early Optical Limits
  19. EP260213a: refined analysis of the EP-FXT observation
  20. EP260213a: Einstein Probe detection of a fast X-ray transient
  21. GRB 260211A: GOTO optical upper limit
  22. Konus-Wind detection of GRB 260207B
  23. GRB260131A/B: 3.6m DOT Optical Observations
  24. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  25. GRB 260211A: SVOM detection of a burst
  26. Konus-Wind detection of GRB 260209B
  27. Konus-Wind detection of GRB 260127B
  28. EP260210a: Global MASTER-Net observations report
  29. EP260210a: refined analysis of the EP-FXT observation
  30. EP260209a: Einstein Probe detection of a fast X-ray transient
  31. EP260210a: Optical upper limits with Kinder observations
  32. GRB 260208C: AstroSat CZTI detection
  33. EP260210a: COLIBRÍ optical upper limit
  34. EP260210a: Einstein Probe detection of an X-ray transient
  35. GRB 260207B: AstroSat CZTI detection
  36. GRB 260208B: AstroSat CZTI detection of a bright long burst
  37. Fermi GRB 260209A: Global MASTER-Net observations report
  38. GRB 260208A: Mondy optical observations
  39. GRB 260208A: 1.3m DFOT optical detection
  40. GRB 260208B: EP-FXT observation
  41. Fermi GRB 260208C: Global MASTER-Net observations report
  42. GRB 260208B: Fermi-LAT detection
  43. GRB 260208A: Fermi-LAT detection
  44. Fermi trigger No 792135758: Global MASTER-Net observations report
  45. GRB 260206A (or XRB from 4U 0513-40): MAXI/GSC detection
  46. GRB 260204A: Swift-XRT observations
  47. GRB 260204A : MASTER Global robotic net optical observations
  48. GRB 260204A: SVOM detection of a burst
  49. GRB 260121A: 239Alferov CubeSat detection
  50. Konus-Wind detection of GRB 260121A
  51. GRB 260131A/B: GTC/OSIRIS+ redshift confimation
  52. GRB 260131A/B: EP/FXT X-ray afterglow detection
  53. Konus-Wind detection of GRB 260128A / EP260128a
  54. Konus-Wind detection of GRB 260131A/B
  55. GRB 260131A/B: GOTO candidate optical counterpart consistent with the MAXI localisation
  56. EP260131a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  57. GRB 260131B: MAXI/GSC detection
  58. GRB 260127B: AstroSat CZTI detection
  59. GRB 260130A: Fermi GBM Detection
  60. EP260131a: Einstein Probe detection of an X-ray transient
  61. GRB 260127B: Fermi GBM Detection
  62. GRB 260130A: Fermi GBM Final Real-time Localization
  63. EP260128a: J band upper limit by SYSU 80cm infrared telescope
  64. GRB 260127A: Swift-BAT refined analysis
  65. GRB 260128B: SVOM detection of a burst through offline search
  66. IPN triangulation of GRB 260127B (short)
  67. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  68. EP260128a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  69. EP260128a: Einstein Probe detection of an X-ray transient
  70. Fermi GRB 260127A: Global MASTER-Net observations report
  71. GRB 260127A: Swift-XRT refined Analysis
  72. GRB 260127B: GOTO candidate optical counterpart
  73. Fermi GRB 260127B: Global MASTER-Net observations report
  74. GRB 260127B: Fermi GBM Final Real-time Localization
  75. GRB 260127A: Swift detection of a burst
  76. EP260126a: Optical upper limit with Kinder observations
  77. EP260126a: Einstein Probe detection of a fast X-ray transient
  78. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  79. Konus-Wind detection of GRB 260120B
  80. GRB 260120A: AstroSat CZTI detection
  81. GRB 260122B: Swift-BAT refined analysis
  82. GRB 260120B: AstroSat CZTI detection
  83. EP260119a: Assy AZT-20 optical observations
  84. EP260119a: Mondy and SAO RAS optical upper limits
  85. Fermi GRB 260120C: Global MASTER-Net observations report
  86. GRB 260120B: Swift-XRT refined Analysis
  87. GRB 260120B: Fermi GBM Observation
  88. SVOM GRB260121.06: Global MASTER-Net observations report
  89. GRB 260120C: Fermi GBM Final Real-time Localization
  90. GRB 260101A: 239Alferov CubeSat detection
  91. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  92. Swift GRB260120B: Global MASTER-Net observations report
  93. GRB 260120B: Fermi GBM Final Real-time Localization
  94. Fermi trigger No 790601190: Global MASTER-Net observations report
  95. Fermi trigger No 790570272: Global MASTER-Net observations report
  96. GRB 260120A: Fermi GBM Final Real-time Localization
  97. EP260119a: update of EP-FXT follow-up observation
  98. SVOM GRB260119.90: Global MASTER-Net observations report
  99. EP260116a: COLIBRÍ detection of a fading optical source
  100. EP260119a: Global MASTER-Net observations report

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