TY  - EJOUR
AU  - Acharyya, A.
AU  - Aufdenberg, J. P.
AU  - Bangale, P.
AU  - Bartkoske, J. T.
AU  - Batista, P.
AU  - Benbow, W.
AU  - Chromey, A. J.
AU  - Davis, J. D.
AU  - Feng, Q.
AU  - Foote, G. M.
AU  - Furniss, A.
AU  - Hanlon, W.
AU  - Hinrichs, C. E.
AU  - Holder, J.
AU  - Jin, W.
AU  - Kaaret, P.
AU  - Kertzman, M.
AU  - Kieda, D.
AU  - Kleiner, T. K.
AU  - Korzoun, N.
AU  - LeBohec, T.
AU  - Lisa, M. A.
AU  - Lundy, M.
AU  - Matthews, N.
AU  - McGrath, C. E.
AU  - Millard, M. J.
AU  - Moriarty, P.
AU  - Nikkhah, S.
AU  - O'Brien, S.
AU  - Ong, R. A.
AU  - Pohl, M.
AU  - Pueschel, E.
AU  - Quinn, J.
AU  - Rabinowitz, P. L.
AU  - Ragan, K.
AU  - Roache, E.
AU  - Rose, J. G.
AU  - Sackrider, J. L.
AU  - Sadeh, I.
AU  - Saha, L.
AU  - Sembroski, G. H.
AU  - Shang, R.
AU  - Tak, D.
AU  - Ticoras, M.
AU  - Tucci, J. V.
AU  - Wong, S. L.
TI  - An Angular Diameter Measurement of β UMa via Stellar Intensity Interferometry with the VERITAS Observatory
IS  - arXiv:2401.01853
M1  - PUBDB-2024-00404
M1  - arXiv:2401.01853
PY  - 2023
AB  - 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.
KW  - atmosphere: model (INSPIRE)
KW  - temperature (INSPIRE)
KW  - interferometer (INSPIRE)
KW  - tracks (INSPIRE)
KW  - VERITAS (INSPIRE)
KW  - observatory (INSPIRE)
KW  - correlation function (INSPIRE)
KW  - Cherenkov counter (INSPIRE)
KW  - air (INSPIRE)
KW  - gamma ray: VHE (INSPIRE)
KW  - photomultiplier (INSPIRE)
KW  - radio wave (INSPIRE)
KW  - frequency (INSPIRE)
KW  - flux (INSPIRE)
KW  - optical (INSPIRE)
KW  - bolometer (INSPIRE)
KW  - imaging (INSPIRE)
KW  - ultraviolet (INSPIRE)
KW  - nucleus (INSPIRE)
LB  - PUB:(DE-HGF)25
DO  - DOI:10.3204/PUBDB-2024-00404
UR  - https://bib-pubdb1.desy.de/record/601892
ER  -