%0 Electronic Article
%A Acharyya, A.
%A Aufdenberg, J. P.
%A Bangale, P.
%A Bartkoske, J. T.
%A Batista, P.
%A Benbow, W.
%A Chromey, A. J.
%A Davis, J. D.
%A Feng, Q.
%A Foote, G. M.
%A Furniss, A.
%A Hanlon, W.
%A Hinrichs, C. E.
%A Holder, J.
%A Jin, W.
%A Kaaret, P.
%A Kertzman, M.
%A Kieda, D.
%A Kleiner, T. K.
%A Korzoun, N.
%A LeBohec, T.
%A Lisa, M. A.
%A Lundy, M.
%A Matthews, N.
%A McGrath, C. E.
%A Millard, M. J.
%A Moriarty, P.
%A Nikkhah, S.
%A O'Brien, S.
%A Ong, R. A.
%A Pohl, M.
%A Pueschel, E.
%A Quinn, J.
%A Rabinowitz, P. L.
%A Ragan, K.
%A Roache, E.
%A Rose, J. G.
%A Sackrider, J. L.
%A Sadeh, I.
%A Saha, L.
%A Sembroski, G. H.
%A Shang, R.
%A Tak, D.
%A Ticoras, M.
%A Tucci, J. V.
%A Wong, S. L.
%T An Angular Diameter Measurement of β UMa via Stellar Intensity Interferometry with the VERITAS Observatory
%N arXiv:2401.01853
%M PUBDB-2024-00404
%M arXiv:2401.01853
%D 2023
%X We use the VERITAS imaging air Cherenkov Telescope (IACT) array to obtain the first measured angular diameter of β UMa at visual wavelengths using stellar intensity interferometry (SII) and independently constrain the limb-darkened angular diameter. The age of the Ursa Major moving group has been assessed from the ages of its members, including nuclear member Merak (β UMa), an A1-type subgiant, by comparing effective temperature and luminosity constraints to model stellar evolution tracks. Previous interferometric limb-darkened angular-diameter measurements of β UMa in the near-infrared (CHARA Array, 1.149 ±0.014 mas) and mid-infrared (Keck Nuller, 1.08 ±0.07 mas), together with the measured parallax and bolometric flux, have constrained the effective temperature. This paper presents current VERITAS-SII observation and analysis procedures to derive squared visibilities from correlation functions. We fit the resulting squared visibilities to find a limb-darkened angular diameter of 1.07 ±0.04 (stat) ±0.05 (sys) mas, using synthetic visibilities from a stellar atmosphere model that provides a good match to the spectrum of β UMa in the optical wave band. The VERITAS-SII limb-darkened angular diameter yields an effective temperature of 9700±200±200 K, consistent with ultraviolet spectrophotometry, and an age of 390±29 ±32  Myr, using MESA Isochrones and Stellar Tracks (MIST). This age is consistent with 408 ±6 Myr from the CHARA Array angular diameter.
%K atmosphere: model (INSPIRE)
%K temperature (INSPIRE)
%K interferometer (INSPIRE)
%K tracks (INSPIRE)
%K VERITAS (INSPIRE)
%K observatory (INSPIRE)
%K correlation function (INSPIRE)
%K Cherenkov counter (INSPIRE)
%K air (INSPIRE)
%K gamma ray: VHE (INSPIRE)
%K photomultiplier (INSPIRE)
%K radio wave (INSPIRE)
%K frequency (INSPIRE)
%K flux (INSPIRE)
%K optical (INSPIRE)
%K bolometer (INSPIRE)
%K imaging (INSPIRE)
%K ultraviolet (INSPIRE)
%K nucleus (INSPIRE)
%F PUB:(DE-HGF)25
%9 Preprint
%R 10.3204/PUBDB-2024-00404
%U https://bib-pubdb1.desy.de/record/601892