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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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

32501 results found.

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

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