Cosmicflows-4: The Calibration of Optical and Infrared Tully–Fisher Relations
Ehsan Kourkchi, R. Brent Tully, Gagandeep S. Anand, Hélène M. Courtois, Alexandra Dupuy, James D. Neill, Luca Rizzi, Mark Seibert
Abstract
Abstract This study is a part of the Cosmicflows-4 project with the aim of measuring the distances of more than ∼10,000 spiral galaxies in the local universe up to ∼15,000 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>km</mml:mi> <mml:mspace width="0.25em"/> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> . New H i line width information has come primarily from the Arecibo Legacy Fast ALFA Survey. Photometry of our sample galaxies has been carried out in optical (SDSS u , g , r , i , and z ) and infrared (WISE W 1 and W 2) bands. Inclinations have been determined using an online graphical interface accessible to a collaboration of citizen scientists. Galaxy distances are measured based on the correlation between the rotation rate of spirals and their absolute luminosity, known as the Tully–Fisher relation (TFR). In this study, we present the calibration of the TFR using a subsample of ∼600 spirals located in 20 galaxy clusters. Correlations among such observables as color, surface brightness, and relative H i content are explored in an attempt to reduce the scatter about the TFR with the goal of obtaining more accurate distances. A preliminary determination of the Hubble constant from the distances and velocities of the calibrator clusters is H 0 = 76.0 ± 1.1(stat.) ± 2.3(sys.) km s −1 Mpc −1 .