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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"

32508 results found.

  1. NuSTAR Transient 260828: SOAR Optical Upper Limits
  2. GRB 260903A: LCO optical observations
  3. GRB 260903A: SVOM/VT optical candidate
  4. GRB 260903A: Retraction of optical counterpart of GCN 45501
  5. GRB 260831A: GECAM-B observation
  6. GRB 260903A: LCO optical counterpart detection
  7. GRB 260827A: Insight-HXMT/HE detection
  8. EP260901a: SVOM/VT optical upper limits
  9. EP260901a: EP-FXT follow-up observation
  10. Konus-Wind detection of GRB 260829A
  11. GRB 260829A: SVOM/GRM observation
  12. GRB 260818A: ATCA detection of a candidate radio counterpart
  13. EP260830a: EP-FXT follow-up observation
  14. EP260901a: Global MASTER-Net observations report
  15. IceCube-260827A: No transient candidates from the Zwicky Transient Facility
  16. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  17. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  18. NuSTAR Transient 260828: LCO Optical Upper Limits
  19. SVOM trigger sb26083106 is not a GRB
  20. GRB 260829A: AstroSat CZTI detection
  21. GRB 260831B: EP-FXT follow-up observation
  22. GRB 260830A: NuSTAR detection of prompt emission
  23. GRB 260831B: LCO optical upper limits
  24. EP260830a: Global MASTER-Net observations report
  25. GRB 260827A: SVOM/GRM observation
  26. IPN triangulation of GRB 260829A
  27. GRB 260827A: Glowbug gamma-ray detection
  28. EP260727a: ATCA 10 GHz detection
  29. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  30. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  31. GRB 260829A: GECAM-B observation of a long burst
  32. GRB 260825A: SVOM/GRM observation of a long burst
  33. GRB 260825A: GECAM-B observation
  34. GRB 260829A: Fermi GBM Detection
  35. GRB 260825A: AstroSat CZTI detection
  36. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  37. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  38. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  39. GRB 260818B: Further EP-FXT observation
  40. GRB 260818B: VLT optical and nIR observations
  41. GRB 260818B: TNG NIR observations
  42. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  43. GRB 260818B: 6 GHz VLA observations
  44. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  45. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  46. GRB 260808B: SAO RAS observations of the optical rebrightening
  47. EP260822a: Global MASTER-Net observations report
  48. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  49. GRB 260807A: EP-FXT follow-up observations
  50. GRB 260822A: SVOM/ECLAIRs refined analysis
  51. GRB 260809A: SVOM/ECLAIRs refined analysis
  52. GRB 260822A: SVOM/VT optical upper limits
  53. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  54. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  55. GRB 260822A: EP/FXT follow-up observations
  56. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  57. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  58. EP260822a: EP-FXT non-detection and upper limit
  59. GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
  60. GRB 260822A: GOTO optical counterpart detection
  61. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  62. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  63. GRB 260822A: LCO optical upper limits
  64. GRB 260822A: GROWTH-India Telescope Upper Limits
  65. GRB 260822A: GOTO optical upper limit
  66. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  67. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  68. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  69. GRB 260818B: VLA radio observations
  70. GRB 260818B: SVOM/C-GFT optical upper limit
  71. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  72. GRB 260820A: Insight-HXMT/HE detection
  73. IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
  74. GRB 260818B: SVOM/GRM observation
  75. GRB 260818B: Insight-HXMT detection
  76. GRB 260818B: EP-FXT follow-up observation
  77. GRB 260818A: J-band observations with WINTER
  78. GRB 260818B: SVOM/ECLAIRs refined analysis
  79. GRB 260818A: SVOM/ECLAIRs refined analysis
  80. GRB 260818B: NOT optical upper limits
  81. GRB 260810A: SVOM/GRM observation
  82. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  83. GRB260818A: EP-FXT follow-up observation
  84. GRB 260818B: LCO optical upper limits
  85. EP260806a: SAO RAS multicolor optical observations
  86. GRB 260818A: LCO optical upper limits
  87. EP260812a: AbAO optical upper limit
  88. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  89. GRB 260810A: Insight-HXMT/HE detection
  90. EP260806a: SVOM/ECLAIRs detection through targeted search
  91. EP260806a: NUTTELA-TAO optical observations
  92. EP260812a: AZT-22 optical upper limit
  93. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  94. EP260806a: WFST optical observations
  95. EP260812b: Optical upper limit with Kinder
  96. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  97. GRB 260808B: Liverpool Telescope further optical observations
  98. GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
  99. EP260812a: NOT and Liverpool Telescope upper limits:
  100. EP260812b: Liverpool Telescope observations

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