Mrk 1419 - a new distance determination

TL;DR

This paper reports a new distance measurement to galaxy Mrk 1419 using water vapor megamasers, demonstrating the potential of geometric methods in cosmology to refine the Hubble constant.

Contribution

It presents the first distance estimate to Mrk 1419 via megamaser observations, contributing to the Megamaser Cosmology Project's goal of precise H0 measurement.

Findings

Distance to Mrk 1419 is 81±10 Mpc.

Megamaser observations can determine galaxy distances geometrically.

Further observations are needed to refine the distance estimate.

Abstract

Water vapor megamasers from the center of active galaxies provide a powerful tool to trace accretion disks at sub-parsec resolution and, through an entirely geometrical method, measure direct distances to galaxies up to 200 Mpc. The Megamaser Cosmology Project (MCP) is formed by a team of astronomers with the aim of identifying new maser systems, and mapping their emission at high angular resolution to determine their distance. Two types of observations are necessary to measure a distance: single-dish monitoring to measure the acceleration of gas in the disk, and sensitive VLBI imaging to measure the angular size of the disk, measure the rotation curve, and model radial displacement of the maser feature. The ultimate goal of the MCP is to make a precise measurement of H0 by measuring such distances to at least 10 maser galaxies in the Hubble flow. We present here the preliminary results from a new maser system, Mrk 1419. Through a model of the rotation from the systemic masers assuming a narrow ring, and combining these results with the acceleration measurement from the Green Bank Telescope, we determine a distance to Mrk 1419 of 81\pm10 Mpc. Given that the disk shows a significant warp that may not be entirely traced by our current observations, more sensitive observations and more sophisticated disk modeling will be essential to improve our distance estimation to this galaxy.