Distances and peculiar velocities of spiral galaxies in the 2MFGC and SFI++ samples

• Published in: Astrophysics Vol. 52; no. 3; pp. 335 - 349
• Main Authors: Kudrya, Yu. N., Karachentseva, V. E., Karachentsev, I. D., Mitronova, S. N., Huchtmeier, W. K.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.07.2009; Springer Nature B.V
• Subjects: Astronomical catalogs; Astronomy; Astrophysics; Astrophysics and Astroparticles; Astrophysics and Cosmology; Correlation coefficient; Correlation coefficients; Dipoles; Infrared imaging systems; Observations and Techniques; Photometry; Physics; Physics and Astronomy; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Spiral galaxies; Stars & galaxies; Velocity; spiral; galaxies; distances; pecular velocities
• ISSN: 0571-7256; 1573-8191
• DOI: 10.1007/s10511-009-9070-8

We compare infrared Tully-Fisher (TF) distances and peculiar velocities derived for spiral galaxies from the two largest datasets: the 2MASS selected Flat Galaxy Catalog 2MFGC and the Arecibo General Catalog with I-band photometry, SFI++. These samples contain peculiar velocities for ~3000 and ~4000 objects, respectively. Based on a sub-sample of ~1000 common very inclined galaxies, we reach the following conclusions. Irrespective of high (SFI++) or low (2MFGC) quality of the photometric data used, both the samples have ~10% fraction of galaxies deviating considerably from the main body of the TF relation. After their deletion, the standard TF scatter drops to 0 m .47 (2MFGC) and 0 m .40 (SFI++). The TF distances, derived from two samples, demonstrate a high degree of mutual agreement with a correlation coefficient ρ = +0 . 95 and σ( H 0 r ) = 837 km/s. Peculiar velocities of the galaxies are also correlated with ρ = 0 . 56−0 . 59 and σ( V pec ) = 610 V pec km/s. We find that the bulk motion of the 2MFGC and SFI++ galaxies on a typical scale of H 0 r ≈ 5700 km/s can be represented by a dipole solution with the amplitude V = (297 ± 23) km/s directed towards { l = 292 0 ± 4 0 , b = −12 0 ± 3 0 }, being only slightly sensitive to different modifications of the TF relaton.