Pulsating stars and the distance scale

Abstract

Abstract. I present an overview of the latest results from the SH0ES project, which obtained homogeneous Hubble Space Telescope (HST) photometry in the optical and nearinfrared for ∼ 3500 and ∼ 2300 Cepheids, respectively, across 19 supernova hosts and 4 calibrators to determine the value of H 0 with a total uncertainty of 2.4%. I discuss the current 3.4σ "tension" between this local measurement and predictions of H 0 based on observations of the CMB and the assumption of "standard" ΛCDM. I review ongoing efforts to reach σ(H 0 ) = 1%, including recent advances on the absolute calibration of Milky Way Cepheid period-luminosity relations (PLRs) using a novel astrometric technique with HST. Lastly, I highlight recent results from another collaboration on the development of new statistical techniques to detect, classify and phase extragalactic Miras using noisy and sparsely-sampled observations. I present preliminary Mira PLRs at various wavelengths based on the application of these techniques to a survey of M33.

VVV-WIT-12 and Its Fashionable Nebula: A 4 yr Long-period Young Stellar Object with a Light Echo?

“…The LPV hypothesis is discarded by examining the magnitudes. The expected magnitude for an LPV with P = 1525 days is M Ks ∼ −11 mag (e.g., Macri 2017). If the object is located at D = 1.6 kpc, its distance modulus would be m − M 0 = 11.02 mag.…”

Zwicky Transient Facility and Globular Clusters: The gr-band Period–Luminosity Relations for Mira Variables at Maximum Light and their Applications to Local Galaxies

“…In light of the recent "Hubble Tension" (for general reviews, see Verde et al 2019;Di Valentino et al 2021;Freedman 2021;Shah et al 2021;Riess et al 2022), Miras offer an independent route to determine the H 0 via the local distance scale ladder, with several advantages being mentioned in Whitelock (2013), Macri (2017), Huang et al (2018Huang et al ( , 2020, and Sanders (2023). On the other hand, Miras are long-period variables implying the long-term monitoring of extragalactic Miras using spacebased telescopes, such as the James Webb Space Telescope, might not be trivial (in terms of scheduling, proposals competitions, etc.).…”

“…On the ground, the 10 yr survey of the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST; Ivezić et al 2019) will naturally provide such a long baseline suitable for Miras. Hence, in combination with its photometric depths, LSST is expected to detect numerous Miras in various types of nearby galaxies (Macri 2017). Indeed, Miras are included in the Roadmap for the LSST Transients and Variable Stars group (Hambleton et al 2022) as one of the scientific targets/goals of the survey.…”