The megamaser cosmology project. I. very long baseline interferometric observations of UGC 3789

2008/11/26 by M. J. Reid, J. A. Braatz, J. J. Condon +3 · 5 citations
Physics and Astronomy · #Accretion (finance) #Astronomy #Astrophysics #Cosmic distance ladder #Cosmology #Cosmology and Gravitation Theories #Dark energy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Hubble's law #Maser #Megamaser #Physics #Radio Astronomy Observations and Technology #Redshift #Supermassive black hole #Very-long-baseline interferometry #astro-ph

paper · pdf · doi:10.1088/0004-637x/695/1/287

published as Astrophys.J.695:287-291,2009 · 18 pages, 3 figures, 4 tables

arxiv created 2008/11/26 · openalex publication_date 2009/03/30 · arxiv updated 2011/02/11 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

The Megamaser Cosmology Project (MCP) seeks to measure the Hubble Constant ( H 0 ) in order to improve the extragalactic distance scale and constrain the nature of dark energy. We are searching for sources of H 2 O maser emission from active galactic nuclei with sub-pc accretion disks, as in NGC 4258, and following up these discoveries with very long baseline interferometric (VLBI) imaging and spectral monitoring. Here we present a VLBI map of the H 2 O masers toward UGC 3789, a galaxy well into the Hubble Flow. We have observed masers moving at rotational speeds up to 800 km s −1 at radii as small as 0.08 pc. Our map reveals masers in a nearly edge-on disk in Keplerian rotation about a 10 7 M ☉ supermassive black hole. When combined with centripetal accelerations, obtained by observing spectral drifts of maser features (to be presented in Paper II), the UGC 3789 masers may provide an accurate determination of H 0 , independent of luminosities and metallicity and extinction corrections.

Citations

• The Discovery of H 2 O Maser Emission in Seven Active Galactic Nuclei and at High Velocities in the Circinus Galaxy
• A 4% Geometric Distance to the Galaxy NGC4258 from Orbital Motions in a Nuclear Gas Disk
• The Proper Motion of Sagittarius A*. II. The Mass of Sagittarius A*
• The Discovery of Water Maser Emission from Eight Nearby Galaxies
• Discovery of Water Maser Emission in Five AGNs and a Possible Correlation Between Water Maser and Nuclear 2–10 keV Luminosities
• Final Results from theHubble Space TelescopeKey Project to Measure the Hubble Constant
• First‐Year Wilkinson Microwave Anisotropy Probe ( WMAP ) Observations: Determination of Cosmological Parameters
• A New Cepheid Distance to the Maser‐Host Galaxy NGC 4258 and Its Implications for the Hubble Constant
• Cosmological consequences of a rolling homogeneous scalar field

Cited by

• Calibrating the cosmic distance scale ladder: the role of the sound-horizon scale and the local expansion rate as distance anchors
• Evidence for coupling of evolved star atmospheres and spiral arms of the Milky Way
• Minimally modified gravity fitting Planck data better than Λ CDM
• TOWARD PRECISION SUPERMASSIVE BLACK HOLE MASSES USING MEGAMASER DISKS
• Discovery of methanimine (CH2NH) megamasers toward compact obscured galaxy nuclei