The bulk motion of flat edge-on galaxies based on 2MASS photometry

Abstract

Abstract.We report the results of applying the 2MASS Tully-Fisher (TF) relations to study galaxy bulk flows. For 1141 all-sky distributed flat RFGC galaxies we construct J, H, K s TF relations and find that Kron J fe magnitudes show the smallest dispersion on the TF diagram. For the sample of 971 RFGC galaxies with V 3K < 18 000 km s −1 we find a dispersion σ TF = 0.42 m and an amplitude of bulk flow V = 199±61 km s• . Our determination of low-amplitude coherent flow is in good agreement with a set of recent data derived from EFAR, PSCz and SCI/SCII samples. The resultant two-dimensional smoothed peculiar velocity field traces well the large-scale density variations in the galaxy distributions. The regions of large positive peculiar velocities lie in the direction of the Great Attractor and Shapley concentration. A significant negative peculiar velocity is seen in the direction of Bootes and in the direction of the Local void. A small positive peculiar velocity (100-150 km s −1 ) is seen towards the Pisces-Perseus supercluster, as well as the Hercules -Coma -Corona Borealis supercluster regions.

Peculiar velocities of 3000 spiral galaxies from the 2MFGC catalog

“…o , and b = −2 o ± 15 o for a sample of 971 galaxies with velocities within 18000 km/s [17]. This result is in good agreement with other published data [18].…”

“…A comparison with Ref. 17 reveals an perfect mutual agreement in the calculated values of V, l , and b. Thus, the manner of selecting disk-shaped galaxies in terms of their optical features (RFGC) or their infrared characteristics (2MFGC) has little effect on the parameters of the dipole solution.…”

HI observations of edge-on spiral galaxies

“…For galaxies having no data on V h or W 50 we calculated their rough predicted radial velocities (V pred ) using two empirical relations between V h and J 20fe (infra-red J magnitude from 2MASS survey, see Kudrya et al 2003), and between V h and (B − J 20fe ) for those RFGC galaxies where these data were available. For the V h prediction we also used a multiparametric relation including such galaxy characteristics as total magnitude, surface brightness index, morphological type and the red to blue diameter ratio.…”

“…The publication of the complete and homogeneous Two Micron All-Sky Survey (2MASS, Skrutskie et al 1997) opens up new opportunities for a cosmic flow study via the NIR TullyFisher relation (Kudrya et al 2003). The majority (71%) of the RFGC galaxies have quite accurate J, H, K photometry in the 2MASS catalogue, but only 25% of them have accurate data on their radial velocities as well as HI line widths.…”

“…A compilation of all accessible data of the heliocentric radial velocity V h and Figure 1 is only available in electronic form at http://www.edpsciences.org Tables 1 and 2 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/435/459 their half power HI line width W 50 for RFGC galaxies was published by Karachentsev et al (2000b). All the above-mentioned data, including the HI data from this paper, were used in our recent publication on a cosmic flow study of RFGC galaxies (Kudrya et al 2003).…”