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This paper involves a data release of the observational campaign: Cosmicflows with Spitzer (CFS). Surface photometry of the 1270 galaxies constituting the survey is presented. An additional ~ 400 galaxies from various other Spitzer surveys are also analyzed. CFS complements the Spitzer Survey of Stellar Structure in Galaxies, that provides photometry for an additional 2352 galaxies, by extending observations to low galactic latitudes (|b|<30 degrees). Among these galaxies are calibrators, selected in K band, of the Tully-Fisher relation. The addition of new calibrators demonstrate the robustness of the previously released calibration. Our estimate of the Hubble constant using supernova host galaxies is unchanged, H0 = 75.2 +/- 3.3 km/s/Mpc. Distance-derived radial peculiar velocities, for the 1935 galaxies with all the available parameters, will be incorporated into a new data release of the Cosmicflows project. The size of the previous catalog will be increased by 20%, including spatial regions close to the Zone of Avoidance.
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We present the distances of 9792 spiral galaxies lying within 15,000 km/s using the relation between luminosity and rotation rate of spiral galaxies. The sample is dominantly, but not exclusively, drawn from galaxies detected in the course of the ALFALFA HI survey with the Arecibo Telescope. Relations between hi line widths and luminosity are calibrated at SDSS u, g, r, i, z bands and WISE W1 and W2 bands. By exploiting secondary parameters, particularly color indices, we address discrepancies between measured distances at different wave bands with unprecedented detail. We provide a catalog that includes reduced kinematic, photometric, and inclination parameters. We also describe a machine learning algorithm, based on the random forest technique that predicts the dust attenuation in spirals lacking infrared photometry. We determine a Hubble Constant value of H0 = 75.1+-0.2 (stat.), with potential systematics up to +-3 km/s/Mpc.
We first discuss why the uncomfortable fine-tuning of the parameters of the Lambda-CDM cosmological model provides continuing, strong motivation to investigate Hubbles Constant. Then we review evidence from the HST Key Project that there is a significant scale error between raw Cepheid and Tully-Fisher distances. An analysis of mainly HST Distance Scale Key Project data shows a correlation between host galaxy metallicity and the rms scatter around the Cepheid P-L relation, which may support a recent suggestion that the P-L metallicity dependence is stronger than expected. If Cepheids do have a significant metallicity dependence then the Tully-Fisher scale error increases and the distances of the Virgo and Fornax clusters extend to more than 20Mpc, decreasing the value of Ho. Finally, if the Cepheids have a metallicity dependence then so do Type Ia Supernovae since the metallicity corrected Cepheid distances to eight galaxies with SNIa would then suggest that the SNIa peak luminosity is fainter in metal poor galaxies, with important implications for SNIa estimates of qo as well as Ho.
Dust extinction and stellar confusion by the Milky Way reduce the efficiency of detecting galaxies at low Galactic latitudes, creating the so-called Zone of Avoidance. This stands as a stumbling block in charting the distribution of galaxies and cosmic flow fields, and therewith our understanding of the local dynamics in the Universe (CMB dipole, convergence radius of bulk flows). For instance, ZoA galaxies are generally excluded from the whole-sky Tully-Fisher Surveys ($|b| leq 5^circ$) even if catalogued. We show here that by fine-tuning the near-infrared TF relation, there is no reason not to extend peculiar velocity surveys deeper into the ZoA. Accurate axial ratios ($b/a$) are crucial to both the TF sample selection and the resulting TF distances. We simulate the effect of dust extinction on the geometrical properties of galaxies. As expected, galaxies appear rounder with increasing obscuration level, even affecting existing TF samples. We derive correction models and demonstrate that we can reliably reproduce the intrinsic axial ratio from the observed value up to extinction level of about $A_Jsimeq3$ mag ($A_Vsim11$ mag), we also recover a fair fraction of galaxies that otherwise would fall out of an uncorrected inclination limited galaxy sample. We present a re-calibration of the 2MTF relation in the NIR $J$, $H$, and $K_s$-bands for isophotal rather than total magnitudes, using their same calibration sample. Both TF relations exhibit similar scatter at high Galactic latitudes. However, the isophotal TF relation results in a significant improvement in the scatter for galaxies in the ZoA, and low surface brightness galaxies in general, because isophotal apertures are more robust in the face of significant stellar confusion.
We study the baryonic Tully-Fisher relation (BTFR) at z=0 using 153 galaxies from the SPARC sample. We consider different definitions of the characteristic velocity from HI and H-alpha rotation curves, as well as HI line-widths from single-dish observations. We reach the following results: (1) The tightest BTFR is given by the mean velocity along the flat part of the rotation curve. The orthogonal intrinsic scatter is extremely small (6%) and the best-fit slope is 3.85+/-0.09, but systematic uncertainties may drive the slope from 3.5 to 4.0. Other velocity definitions lead to BTFRs with systematically higher scatters and shallower slopes. (2) We provide statistical relations to infer the flat rotation velocity from HI line-widths or less extended rotation curves (like H-alpha and CO data). These can be useful to study the BTFR from large HI surveys or the BTFR at high redshifts. (3) The BTFR is more fundamental than the relation between angular momentum and galaxy mass (the Fall relation). The Fall relation has about 7 times more scatter than the BTFR, which is merely driven by the scatter in the mass-size relation of galaxies. The BTFR is already the fundamental plane of galaxy discs: no value is added with a radial variable as a third parameter.
We estimate the stellar masses of disk galaxies with two independent methods: a photometrically self-consistent color$-$mass-to-light ratio relation (CMLR) from population synthesis models, and the Baryonic Tully-Fisher relation (BTFR) calibrated by gas rich galaxies. These two methods give consistent results. The CMLR correctly converts distinct Tully-Fisher relations in different bands into the same BTFR. The BTFR is consistent with $M_b propto V_f^4$ over nearly six decades in mass, with no hint of a change in slope over that range. The intrinsic scatter in the BTFR is negligible, implying that the IMF of disk galaxies is effectively universal. The gas rich BTFR suggests an absolute calibration of the stellar mass scale that yields nearly constant mass-to-light ratios in the near-infrared (NIR): $0.57;M_{odot}/L_{odot}$ in $K_s$ and $0.45;M_{odot}/L_{odot}$ at $3.6mu$. There is only modest intrinsic scatter ($sim 0.12$ dex) about these typical values. There is no discernible variation with color or other properties: the NIR luminosity is a good tracer of stellar mass.
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