An Angular Diameter Measurement of $\beta$ UMa via Stellar Intensity Interferometry with the VERITAS Observatory

Acharyya, A.; Rabinowitz, P. L.; Quinn, J.; Kieda, D.; Rose, J. G.; Holder, J.; Kertzman, M.; Kaaret, P.; Kleiner, T. K.; Sackrider, J. L.; VERITAS Collaboration; Tak, D.; Sembroski, G. H.; Aufdenberg, J. P.; Lundy, M.; Hanlon, W.; Saha, L.; Ragan, K.; Jin, W.; Sadeh, I.; Furniss, A.; Batista, P.; Feng, Q.; Chromey, A. J.; Shang, R.; Roache, E.; Millard, M. J.; Benbow, W.; LeBohec, T.; O'Brien, S.; Nikkhah, S.; McGrath, C. E.; Davis, J. D.; Tucci, J. V.; Lisa, M. A.; Moriarty, P.; Matthews, N.; Foote, G. M.; Ticoras, M.; Bangale, P.; Bartkoske, J. T.; Pohl, M.; Wong, S. L.; Hinrichs, C. E.; Ong, R. A.; Pueschel, E.; Korzoun, N.

Preprint

PUBDB-2024-00404

An Angular Diameter Measurement of $\beta$ UMa via Stellar Intensity Interferometry with the VERITAS Observatory

Acharyya, A. ; Aufdenberg, J. P. ; Bangale, P. ; Bartkoske, J. T. ; Batista, P.DESY* ; Benbow, W. ; Chromey, A. J. ; Davis, J. D. ; Feng, Q. ; Foote, G. M. ; Furniss, A. ; Hanlon, W. ; Hinrichs, C. E. ; Holder, J. ; Jin, W. ; Kaaret, P. ; Kertzman, M. ; Kieda, D. ; Kleiner, T. K.DESY* ; Korzoun, N. ; LeBohec, T. ; Lisa, M. A. ; Lundy, M. ; Matthews, N. ; McGrath, C. E. ; Millard, M. J. ; Moriarty, P. ; Nikkhah, S. ; O'Brien, S. ; Ong, R. A. ; Pohl, M. ; Pueschel, E.DESY* ; Quinn, J. ; Rabinowitz, P. L. ; Ragan, K. ; Roache, E. ; Rose, J. G. ; Sackrider, J. L. ; Sadeh, I.DESY* ; Saha, L. ; Sembroski, G. H. ; Shang, R. ; Tak, D.DESY* ; Ticoras, M. (Corresponding author) ; Tucci, J. V. ; Wong, S. L. ; VERITAS Collaboration (Collaboration author)

2023

[10.3204/PUBDB-2024-00404]

This record in other databases:

Please use a persistent id in citations: doi:10.3204/PUBDB-2024-00404

Report No.: arXiv:2401.01853

Abstract: We use the VERITAS imaging air Cherenkov Telescope (IACT) array to obtain the first measured angular diameter of $\beta$ 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 ($\beta$ 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 $\beta$ UMa in the near-infrared (CHARA Array, $1.149 \pm 0.014$ mas) and mid-infrared (Keck Nuller, $1.08 \pm 0.07$ 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 $1.07 \pm 0.04 {\rm (stat)} \pm 0.05$ (sys) mas, using synthetic visibilities from a stellar atmosphere model that provides a good match to the spectrum of $\beta$ UMa in the optical wave band. The VERITAS-SII limb-darkened angular diameter yields an effective temperature of $9700\pm200\pm 200$ K, consistent with ultraviolet spectrophotometry, and an age of $390\pm 29 \pm 32 $ Myr, using MESA Isochrones and Stellar Tracks (MIST). This age is consistent with $408 \pm 6$ Myr from the CHARA Array angular diameter.

Keyword(s): atmosphere: model ; temperature ; interferometer ; tracks ; VERITAS ; observatory ; correlation function ; Cherenkov counter ; air ; gamma ray: VHE ; photomultiplier ; radio wave ; frequency ; flux ; optical ; bolometer ; imaging ; ultraviolet ; nucleus