16453
收藏DataCite Commons2023-04-21 更新2025-04-15 收录
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http://esdcdoi.esac.esa.int/doi/html/data/astronomy/hst/16453.html
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The local measurement of the Hubble constant comma H0 comma is now in tension with measurements from the distant universe by 4.4 sigma. The local H0 value is based on using Type Ia Supernovae (SNe Ia) as standard candles comma calibrated from a small sample (<20) of nearby galaxies and limited by the (in)frequency of SN Ia events. One of the biggest improvements we can make in measuring H0 locally is to increase the number of calibrating systems. A new SN Ia event has just occurred in the nearby galaxy NGC 4457 comma estimated to be at virgul17 Mpc based on the light-curve. The host galaxy is close enough that a precision distance can be made using the tip of the red giant branch (TRGB) method. We propose ACS+WFC3 imaging of the resolved stars in the galaxy to precisely measure the distance and calibrate the SN Ia luminosity. A statistical sample of galaxies with SNe Ia and independent distance measurements is the ultimate goal for improving the local H0 measurement and such a sample is only built galaxy-by-galaxy when a nearby SN Ia occurs. In this context comma NGC 4457 is a high priority target for a precision TRGB distance measurement. In addition comma the host-galaxy NGC 4457 is a more massive galaxy with little recent star formation. These properties are unique among SNe Ia calibrating systems but common in galaxies in the Hubble flow. SNe Ia in massive hosts standardize to a luminosity up to 10% brighter than those in lower mass hosts comma a potential source of systematic uncertainty in the SN Ia distance scale. The new TRGB distance will provide an independent distance to a SN Ia in a galaxy with such properties and enable a comparison with SN Ia luminosity offsets estimated from galaxy redshifts.
提供机构:
European Space Agency
创建时间:
2023-04-21



