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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"

26308 results found.

  1. GRB 260831A: GECAM-B observation
  2. GRB 260903A: LCO optical counterpart detection
  3. GRB 260827A: Insight-HXMT/HE detection
  4. GRB 260903A: SVOM detection of a soft faint burst
  5. EP260901a: SVOM/VT optical upper limits
  6. Konus-Wind detection of GRB 260829A
  7. GRB 260829A: SVOM/GRM observation
  8. GRB 260818A: ATCA detection of a candidate radio counterpart
  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. EP260901a: EP-WXT detection of a fast X-ray transient
  14. SVOM trigger sb26083106 is not a GRB
  15. GRB 260829A: AstroSat CZTI detection
  16. GRB 260831B: EP-FXT follow-up observation
  17. GRB 260830A: NuSTAR detection of prompt emission
  18. GRB 260831B: LCO optical upper limits
  19. EP260830a: EP-WXT detection of a fast X-ray transient
  20. GRB 260827A: SVOM/GRM observation
  21. NuSTAR 260828: a 1100s hard X-ray transient
  22. GRB 260831B: SVOM detection of a possible burst
  23. IPN triangulation of GRB 260829A
  24. GRB 260827A: Glowbug gamma-ray detection
  25. EP260727a: ATCA 10 GHz detection
  26. GRB 260829A: GECAM-B observation of a long burst
  27. GRB 260825A: SVOM/GRM observation of a long burst
  28. GRB 260825A: GECAM-B observation
  29. GRB 260829A: Fermi GBM Detection
  30. GRB 260825A: AstroSat CZTI detection
  31. GRB 260818B: Further EP-FXT observation
  32. GRB 260818B: VLT optical and nIR observations
  33. GRB 260818B: TNG NIR observations
  34. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  35. GRB 260818B: 6 GHz VLA observations
  36. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  37. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  38. GRB 260808B: SAO RAS observations of the optical rebrightening
  39. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  40. GRB 260807A: EP-FXT follow-up observations
  41. GRB 260822A: SVOM/ECLAIRs refined analysis
  42. GRB 260809A: SVOM/ECLAIRs refined analysis
  43. GRB 260822A: SVOM/VT optical upper limits
  44. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  45. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  46. GRB 260822A: EP/FXT follow-up observations
  47. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  48. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  49. EP260822a: EP-FXT non-detection and upper limit
  50. GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
  51. GRB 260822A: GOTO optical counterpart detection
  52. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  53. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  54. EP260822a: Einstein Probe detection of a fast X-ray transient
  55. GRB 260822A: LCO optical upper limits
  56. GRB260822B: Fermi GBM Final Localization
  57. GRB 260822A: GROWTH-India Telescope Upper Limits
  58. GRB 260822A: GOTO optical upper limit
  59. GRB 260822A: SVOM detection of a short burst
  60. GRB 260818B: VLA radio observations
  61. GRB 260818B: SVOM/C-GFT optical upper limit
  62. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  63. GRB 260820A: Insight-HXMT/HE detection
  64. IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
  65. GRB 260818B: SVOM/GRM observation
  66. EP detected a brightening of LMXB 1ES 1735-26.9
  67. GRB 260818B: Insight-HXMT detection
  68. GRB 260818B: EP-FXT follow-up observation
  69. GRB 260818A: J-band observations with WINTER
  70. GRB 260818B: SVOM/ECLAIRs refined analysis
  71. GRB 260818A: SVOM/ECLAIRs refined analysis
  72. GRB 260818B: NOT optical upper limits
  73. GRB 260810A: SVOM/GRM observation
  74. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  75. GRB260818A: EP-FXT follow-up observation
  76. GRB 260818B: LCO optical upper limits
  77. GRB 260818B: SVOM detection of a short burst
  78. SVOM trigger sb26081806 is not a GRB
  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. GRB 260818A: SVOM possible detection of a long and faint GRB
  85. EP260806a: SVOM/ECLAIRs detection through targeted search
  86. EP260806a: NUTTELA-TAO optical observations
  87. EP260812a: AZT-22 optical upper limit
  88. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  89. EP260806a: WFST optical observations
  90. EP260812b: Optical upper limit with Kinder
  91. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  92. GRB 260808B: Liverpool Telescope further optical observations
  93. EP260812a: NOT and Liverpool Telescope upper limits:
  94. EP260812b: GOTO detection of the optical counterpart
  95. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  96. EP260812a: SVOM/C-GFT optical upper limit
  97. EP260812b: COLIBRÍ optical observations
  98. EP260812b: SVOM/VT optical observation
  99. GRB 260808A: SVOM/GRM observation
  100. EP260812b: Einstein Probe detection of an X-ray transient

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