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Local Group dwarf spheroidal satellite galaxies are the faintest extragalactic stellar systems known. We examine recent data for these objects in the plane of the Baryonic Tully-Fisher Relation (BTFR). While some dwarf spheroidals adhere to the BTFR, others deviate substantially. We examine the residuals from the BTFR and find that they are not random. The residuals correlate with luminosity, size, metallicity, ellipticity, and susceptibility of the dwarfs to tidal disruption in the sense that fainter, more elliptical, and tidally more susceptible dwarfs deviate farther from the BTFR. These correlations disfavor stochastic processes and suggest a role for tidal effects. We identify a test to distinguish between the {\Lambda}CDM and MOND based on the orbits of the dwarf satellites of the Milky Way and how stars are lost from them., Comment: 16 pages, 7 figures. Submitted to ApJ. Revised in response to referee report

The Tully-Fisher relation of spiral galaxies shows notable dependence on morphological types, with earlier type spirals having systematically lower luminosity at fixed maximum rotation velocity $V_{max}$. This decrement of luminosity is more significant in shorter wavelengths. By modeling the rotation curve and stellar population of different morphological type spiral galaxies in combination, we find the $V_{max}$ of spiral galaxies is weakly dependent on the morphological type, whereas the difference of the stellar population originating from the bulge disk composition effect mainly account for the morphological type dependence of the Tully-Fisher relation., Comment: 8 pages, 3 figures, ApJ accepted

We present a simulation of the cosmic evolution of the atomic and molecular phases of the cold hydrogen gas in about 3e7 galaxies, obtained by post-processing the virtual galaxy catalog produced by (De Lucia et al. 2007) on the Millennium Simulation of cosmic structure (Springel et al. 2005). Our method uses a set of physical prescriptions to assign neutral atomic hydrogen (HI) and molecular hydrogen (H2) to galaxies, based on their total cold gas masses and a few additional galaxy properties. These prescriptions are specially designed for large cosmological simulations, where, given current computational limitations, individual galaxies can only be represented by simplistic model-objects with a few global properties. Our recipes allow us to (i) split total cold gas masses between HI, H2, and Helium, (ii) assign realistic sizes to both the HI- and H2-disks, and (iii) evaluate the corresponding velocity profiles and shapes of the characteristic radio emission lines. The results presented in this paper include the local HI- and H2-mass functions, the CO-luminosity function, the cold gas mass--diameter relation, and the Tully-Fisher relation (TFR), which all match recent observational data from the local Universe. We also present high-redshift predictions of cold gas diameters and the TFR, both of which appear to evolve markedly with redshift., 19 pages, 15 figures

The galaxy circular velocity function at small masses is related to the matter power spectrum on small scales. Although this function is well-studied for Local Group dwarfs, theoretical predictions and observational measurements are difficult for satellite galaxies, because of ram pressure and tidal stripping. By contrast, isolated dwarf galaxies are less affected by these processes, and almost always have enough 21cm emission to trace their dynamics robustly. Here, we test cold dark matter cosmology using isolated low mass dwarf galaxies from the SDSS with measured 21cm widths. We find consistency between the predicted and observed number density of isolated galaxies down to circular velocities of 50 km/s. Our technique yields a direct test of small-scale cosmology independent of the Lyman-alpha forest power spectrum, but our sample is currently statistically less powerful: warm dark matter particles heavier than 0.5 keV cannot be ruled out. Our major systematic uncertainty is the surface brightness limit of the SDSS. Blind HI surveys, such as the ALFALFA survey on Arecibo, will uncover a larger number of isolated low mass galaxies and increase the power of our constraints. With our sample, we also find that the Tully-Fisher relation for dwarf galaxies is a strong function of environment, and that the baryonic fraction is only a weak function of mass. These results suggest that for dwarf galaxies, gas loss is dominated by external, not internal, processes. [abridged], Comment: submitted to ApJ

The 2 Micron All-Sky Survey (2MASS) Tully-Fisher Survey (2MTF) aims to measure Tully-Fisher (TF) distances to all bright inclined spirals in the 2MASS Redshift Survey (2MRS). Essential to this project is a universal calibration of the TF relation in the 2MASS J (1.2 um), H (1.6 um) and K (2.2 um) bands. We present the first bias corrected or universal TF template in these bands. We find that the slope of the TF relation becomes steeper as the wavelength increases being close to L \propto v^4 in K-band and L \propto v^3.6 in J and H-bands. We also investigate the dependence on galaxy morphology showing that in all three bands the relation is steeper for later type spirals which also have a dimmer TF zeropoint than earlier type spirals. We correct the final relation to that for Sc galaxies. Finally we study the scatter from the TF relation fitting for a width dependent intrinsic scatter which is not found to vary significantly with wavelength.

The integrated line width derived from CO spectroscopy provides a powerful tool to study the internal kinematics of extragalactic objects, including quasars at high redshift, provided that the observed line width can be properly translated to more conventionally used kinematical parameters of galaxies. We show, through construction of a K-band CO Tully-Fisher relation for nearby galaxies spanning a wide range in infrared luminosity, that the CO line width measured at 20% of the peak intensity, when corrected for inclination and other effects, successfully recovers the maximum rotation velocity of the disk. The line width at 50% of the peak intensity performs much more poorly, in large part because CO lines have a wide range of profiles, which are shown to vary systematically with infrared luminosity. We present a practical prescription for converting observed CO line widths into the stellar velocity dispersion of the bulge (sigma), and then apply it to a sample of low-redshift (z < 0.2) and high-redshift (1.4 < z < 6.4) quasars to study their host galaxies. Nearby quasars roughly fall on the correlation between black hole mass and bulge stellar velocity dispersion established for inactive galaxies, but the host galaxies of the high-z quasars systematically deviate from the local M_BH-sigma relation. At a given sigma, high-z quasars have black hole masses larger by a factor of 4 relative to local galaxies, suggesting that early in the life-cycle of galaxies the development of the bulge lags behind the growth of the central black hole. An alternative explanation for these observations, which currently cannot be ruled out rigorously, is that high-redshift quasars are preferentially viewed at face-on orientations., To appear in ApJ; 10 pages

Using moderate-resolution Keck spectra, we have examined the velocity profiles of 15 members of cluster Cl0024+1654 at z=0.4. WFPC2 images of the cluster members have been used to determine structural parameters, including disk sizes, orientations, and inclinations. We compare two methods of optical rotation curve analysis for kinematic measurements. Both methods take seeing, slit size and orientation, and instrumental effects into account and yield similar rotation velocity measurements. Four of the galaxies in our sample exhibit unusual kinematic signatures, such as non-circular motions. Our key result is that the Cl0024 galaxies are marginally underluminous (0.50 +/- 0.23 mag), given their rotation velocities, as compared to the local Tully-Fisher relation. In this analysis, we assume no slope evolution, and take into account systematic differences between local and distant velocity and luminosity measurements. Our result is particularly striking considering the Cl0024 members have very strong emission lines, and local galaxies with similar Halpha equivalent widths tend to be overluminous on the Tully-Fisher relation. Cl0024 Tully-Fisher residuals appear to be correlated most strongly with galaxy rotation velocities, indicating a possible change in the slope of the Tully-Fisher relation. However, we caution that this result may be strongly affected by magnitude selection and by the original slope assumed for the analysis. Cl0024 residuals also depend weakly on color, emission line strength and extent, and photometric asymmetry. In a comparison of stellar and gas motions in two Cl0024 members, we find no evidence for counter-rotating stars and gas, an expected signature of mergers., 38 pages, 10 figures, accepted for publication in ApJ; version with full-resolution figures can be downloaded from http://www.ucolick.org/~anne/recent_pubs.html

I investigate the Baryonic Tully-Fisher relation for a sample of galaxies with extended 21 cm rotation curves spanning the range 20 < Vf < 300 km/s. A variety of scalings of the stellar mass-to-light ratio are considered. For each prescription for M/L, I give fits of the form Md = A Vf^x. Presumably, the prescription that comes closest to the correct value will minimize the scatter in the relation. The fit with minimum scatter has A = 50 solar masses/(km/s)^4 and x = 4. This relation holds over five decades in mass. Galaxy color, stellar fraction, and M/L are correlated with each other and with Md, in the sense that more massive galaxies tend to be more evolved. There is a systematic dependence of the degree of maximality of disks on surface brightness. High surface brightness galaxies typically have M/L ~ 3/4 of the maximum disk value, while low surface brightness galaxies typically attain ~ 1/4 of this amount., ApJ, accepted. 13 pages including 7 embedded figures and 6 tables. Added some references to latest version

We present new long-slit Halpha spectroscopy for 403 non-interacting spiral galaxies, obtained at the Palomar Observatory 5 m Hale telescope, which is used to derive well-sampled optical rotation curves. Because many of the galaxies show optical emission features which are significantly extended along the spectrograph slit, a technique was devised to separate and subtract the night sky lines from the galaxy emission. We exploit a functional fit to the rotation curve to identify its center of symmetry; this method minimizes the asymmetry in the final, folded rotation curve. We derive rotational widths using both velocity histograms and the Polyex model fit. The final rotational width is measured at a radius containing 83% of the total light as derived from I-band images. In addition to presenting the new data, we use a large sample of 742 galaxies for which both optical long-slit and radio HI line spectroscopy are available to investigate the relation between the HI content of the disks and the extent of their rotation curves. Our results show that the correlation between those quantities, which is well-established in the case of HI-poor galaxies in clusters, is present also in HI-normal objects: for a given optical size, star formation can be traced further out in the disks of galaxies with larger HI mass., 16 pages, 6 figures. Full version of Table 1 and Figure 5 available as separate files. To appear in AJ (September 2005)

We investigate the properties of the B-band Tully-Fisher (T-F) relation for 25 compact group galaxies, using Vmax derived from 2-D velocity maps. Our main result is that the majority of the Hickson Compact Group galaxies lie on the T-F relation. However, about 20% of the galaxies, including the lowest-mass systems, have higher B luminosities for a given mass, or alternatively, a mass which is too low for their luminosities. We favour a scenario in which outliers have been brightened due to either enhanced star formation or merging. Alternatively, the T-F outliers may have undergone truncation of their dark halo due to interactions. It is possible that in some cases, both effects contribute. The fact that the B-band T-F relation is similar for compact group and field galaxies tells us that these galaxies show common mass-to-size relations and that the halos of compact group galaxies have not been significantly stripped inside R25. We find that 75% of the compact group galaxies studied (22 out of 29) have highly peculiar velocity fields. Nevertheless, a careful choice of inclination, position angle and center, obtained from the velocity field, and an average of the velocities over a large sector of the galaxy enabled the determination of fairly well-behaved rotation curves for the galaxies. However, two of the compact group galaxies which are the most massive members in M51--like pairs, HCG 91a and HCG 96a, have very asymmetric rotation curves, with one arm rising and the other one falling, indicating, most probably, a recent perturbation by the small close companions., 15 pages, 4 figures, accepted for publication in the Astronomical Journal

Using mean relative peculiar velocity measurements for pairs of galaxies, we estimate the cosmological density parameter Ωm and the amplitude of density fluctuations σ8. Our results suggest that our statistic is a robust and reproducible measure of the mean pairwise velocity and thereby the Ωm parameter. We get Ωm = 0.30 and σ8 = 1.13. These estimates do not depend on prior assumptions on the adiabaticity of the initial density fluctuations, the ionization history, or the values of other cosmological parameters.

We present Very Large Array (VLA) H I imaging of four low surface brightness (LSB) galaxies ([OBC97] P01-3, [OBC97] C06-1, [OBC97] C04-1, [OBC97] C04-2), which were thought to strongly deviate from the Tully-Fisher (TF) relation based on Arecibo single-dish observations. We do not detect three of the four targeted low surface brightness galaxies (LSBs) in H I down to a 4 ? limit of 0.08 Jy km s-1. We find that two of the four of these LSBs have bright galaxies at projected distances of 26 and 29, which have contaminated the Arecibo signal. A further examination of the Arecibo sample shows that five out of the six galaxies that were found to deviate from the TF relation have nearby bright galaxies (within 35 and within the observed H I velocity range), and we conclude that possibly all but one of the non-TF galaxies are contaminated by H I from nearby galaxies. The sixth galaxy was not detected by us. A new observation by Arecibo did not confirm the earlier detection. We present the H I properties, kinematics, and rotation curves of three bright galaxies NGC 7631, KUG 2318+078, NGC 2595 which happened to be in the LSB fields and of two LSB galaxies, one of the targeted ones C04-2 and one (UGC 12535 or P01-1) that was found in the field of P01-3. The two detected LSB galaxies fall within 2 ? on the TF relation. The integrated profiles of the bright galaxies are consistent with the Arecibo results both in velocity range and amplitude, which indicates that most of the extreme deviators from the TF relation must have been affected by bright companions in this earlier H I survey. A more recent determination of the sidelobe structure of the Arecibo beam supports our conclusion and shows that the degree of sidelobe contamination was much larger than could have been initially predicted. If the now unknown velocities of these nondetected LSB's are within our probed velocity range then the limit to their H I mass is roughly 108 M? assuming H0 = 75 km s-1 Mpc-1. Hence, we have corrected the results found in O'Neil et al. (2000a) and have reconstructed the TF relation. These new observations then show (1) a reconstructed TF relation that has relatively large scatter at all values of rotational velocity (possibly indicating the true range in disk galaxy properties) and (2) the presence of at least some red, gas-poor, LSB disks that indeed may be in an advanced evolutionary state as the faded remnants of their former high surface brightness actively star-forming state.

We present new semi-analytical models for the formation of disk galaxies with the purpose of investigating the origin of the near-infrared Tully-Fisher (TF) relation. The models assume that disks are formed by cooling of the baryons inside dark halos with realistic density profiles, and that the baryons conserve their specific angular momentum. Only gas with densities above the critical density given by Toomre's stability criterion is considered eligible for star formation, and a simple recipe for supernovae feedback is included. We emphasize the importance of extracting the proper luminosity and velocity measures from the models, something that has often been ignored in the past. The observed K-band TF relation has a slope that is steeper than simple predictions based on dynamical arguments suggest. Taking the stability related star formation threshold densities into account steepens the TF relation, decreases its scatter, and yields gas mass fractions that are in excellent agreement with observations. In order for the TF slope to be as steep as observed, further physics are required. We argue that the characteristics of the observed near-infrared TF relation do not reflect systematic variations in stellar populations, or cosmological initial conditions, but are governed by feedback. Finally we show that our models provide a natural explanation for the small amount of scatter that makes the TF relation useful as a cosmological distance indicator., 20 pages, 10 figures. Accepted for publication in ApJ

[Abridged] Using the refurbished 305m Arecibo Gregorian Telescope, we detected 43 low surface brightness (LSB) galaxies from the catalog of O'Neil, Bothun, & Cornell (1997a). The detected galaxies range from 22.0 mag/arcsec^2 < mu_B(0) < 25.0 mag/arcsec^2, with colors ranging from the blue through the first detection of a very red LSB galaxies (B-V = -0.7 to 1.7). The M_HI/L_B of these galaxies ranges from 0.1 Msol/Lsol -- 50 Msol/Lsol, showing this sample to range from very gas poor to possibly the most gas rich galaxies ever detected. One of the more intriguing results of this survey is that the galaxies with the highest M_HI/L_B correspond to some of the reddest (optically) galaxies in the survey, raising the question of why star formation has not continued in these galaxies. Since the average H I column density in these systems is above the threshold for massive star formation, the lack of such may indicate that these galaxies form some kind of ``optical core'' which trace a much more extended distribution of neutral hydrogen. A subset of the detected LSB galaxies have rotational velocities > 200 km s^{-1} and yet are at least an order of magnitude below L* in total luminosity. As such, they represent extreme departure from the standard Tully-Fisher relation. In fact, our sample does not appear to have any significant correlation between the velocity widths and absolute magnitudes, with only 40% of the galaxies falling within the 1 sigma low surface brightness galaxy Tully-Fisher relation., 39 pages, 10 figures. & 4 tables. Accepted by AJ

We present an I-band Tully-Fisher relation (TFR) for 18 nearby S0 galaxies using kinematics derived from long slit spectroscopy of stellar absorption lines. Our estimates of the circular velocity, V_c, at 2-3 exponential disk scale lengths account for line-of-sight projection and for the stellar random motions through an asymmetric drift correction. Uniform and accurate distance calibration for all objects is available from surface brightness fluctuation measurements of Tonry et al. (1998). Despite the care taken in estimating both V_c and M_I, the TFR shows an intrinsic scatter, $\sim 0.7$ mag in M_I, or 0.15 in log_10(V_c). This result is surprising, as S0 galaxies appear to have both the simple kinematics of disk galaxies, and the simple stellar populations of early-type galaxies. Remarkably, in this sample of overall rotation-dominated galaxies, the central stellar velocity dispersion is a better predictor of the total I-band luminosity (through the Fundamental Plane relations) than the circular speed at several exponential scale lengths. Furthermore, the TFR zeropoint, or the mean stellar I-band luminosity at a given V_c, differs by only $\sim 0.5$ mag between our sample of S0s and Mathewson et al.'s (1992) sample of late-type spirals, once both data sets are brought onto a consistent distance scale. This offset is less than expected if S0s are former spiral galaxies with prematurely truncated star-formation ($\gtorder 4$ Gyrs ago)., Comment: To appear in AJ, June 1999 issue. AAS LaTex, 17 pages + table and figures

The first results from a Tully-Fisher (TF) survey of cluster galaxies are presented. The galaxies are drawn from fifteen Abell clusters that lie in the redshift range 9000-12,000 km/sec and are distributed uniformly around the celestial sky. The data set consists of R-band CCD photometry and long- slit H-alpha spectroscopy. The rotation curves (RCs) are characterized by a turnover radius (r_t) and an asymptotic velocity v_a, while the surface brightness profiles are characterized in terms of an effective exponential surface brightness I_e and a scale length r_e. The TF scatter is minimized when the rotation velocity is measured at 2.0 +/- 0.2 r_e; a significantly larger scatter results when the rotation velocity is measured at > 3 or < 1.5 scale lengths. This effect demonstrates that RCs do not have a universal form, as has been suggested by Persic, Salucci, and Stel. In contrast to previous studies, a modest but statistically significant surface-brightness dependence of the TF relation is found, log v = const + 0.28*log L + 0.14*log I_e. This indicates a stronger parallel between the TF relation and the FP relations of elliptical galaxies than has previously been recognized. Future papers in this series will consider the implications of this cluster sample for deviations from Hubble flow on 100-200 Mpc scales.

A compilation of 21 cm line spectral parameters specifically designed for application of the Tully-Fisher (TF) distance method is presented for 1201 spiral galaxies, primarily field Sc galaxies, for which optical I-band photometric imaging is also available. New H I line spectra have been obtained for 881 galaxies. For an additional 320 galaxies, spectra available in a digital archive have been reexamined to allow application of a single algorithm for the derivation of the TF velocity width parameter. A velocity width algorithm is used that provides a robust measurement of rotational velocity and permits an estimate of the error on that width taking into account the effects of instrumental broadening and signal-to-noise. The digital data are used to establish regression relations between measurements of velocity widths using other common prescriptions so that comparable widths can be derived through conversion of values published in the literature. The uniform H I line widths presented here provide the rotational velocity measurement to be used in deriving peculiar velocities via the TF method.

Properties derived from the analysis of photometric I-band imaging observations are presented for 1727 inclined spiral galaxies, mostly of types Sbc and Sc. The reduction, parameter extraction, and error estimation procedures are discussed in detail. The asymptotic behavior of the magnitude curve of growth and the radial variation in ellipticity and position angle are used in combination with the linearity of the surface brightness falloff to fit the disk portion of the profile. Total I-band magnitudes are calculated by extrapolating the detected surface brightness profile to a radius of eight disk scale lengths. Errors in the magnitudes, typically ~0.04 mag, are dominated by uncertainties in the sky subtraction and disk-fitting procedures. Comparison is made with the similar imaging database of Mathewson, Ford, & Buchhorn, both as presented originally by those authors and after reanalyzing their digital reduction files using identical disk-fitting procedures. Direct comparison is made of profile details for 292 galaxies observed in common. Although some differences occur, good agreement is found, proving that the two data sets can be used in combination with only minor accommodation of those differences. The compilation of optical properties presented here is optimized for use in applications of the Tully-Fisher relation as a secondary distance indicator in studies of the local peculiar velocity field.

We use high-resolution cosmological simulations that include the effects of gasdynamics and star formation to investigate the origin of the Tully-Fisher relation in the standard Cold Dark Matter cosmogony. Luminosities are computed for each model galaxy using their full star formation histories and the latest spectrophotometric models. We find that at z=0 the stellar mass of model galaxies is proportional to the total baryonic mass within the virial radius of their surrounding halos. Circular velocity then correlates tightly with the total luminosity of the galaxy, reflecting the equivalence between mass and circular velocity of systems identified in a cosmological context. The slope of the relation steepens slightly from the red to the blue bandpasses, and is in fairly good agreement with observations. Its scatter is small, decreasing from \~0.45 mag in the U-band to ~0.34 mag in the K-band. The particular cosmological model we explore here seems unable to account for the zero-point of the correlation. Model galaxies are too faint at z=0 (by about two magnitudes) if the circular velocity at the edge of the luminous galaxy is used as an estimator of the rotation speed. The Tully-Fisher relation is brighter in the past, by about ~0.7 magnitudes in the B-band at z=1, at odds with recent observations of z~1 galaxies. We conclude that the slope and tightness of the Tully-Fisher relation can be naturally explained in hierarchical models but that its normalization and evolution depend strongly on the star formation algorithm chosen and on the cosmological parameters that determine the universal baryon fraction and the time of assembly of galaxies of different mass., 5 pages, 4 figures included, submitted to ApJ (Letters)

We investigate the viability and precision of using 12CO (J = 1 → 0) emission lines from galaxies in lieu of 21 cm emission in the Tully-Fisher distance indicator (TF). Here we combine CO data gathered specifically for Tully-Fisher analysis with I-band photometry (both new and from the literature) for cluster galaxies between 3500 and 8000 km s-1 and compare the luminosity–line width relation using CO with the results of recent, large TF surveys using H I and Hα. We cull some CO data as suggested by previously published numerical simulations and find that CO line widths, with corrections for turbulence and noise-broadening on the order of 35 km s-1, behave identically to H I and Hα in luminosity–line width analyses. We also examine the relation between CO line shapes and other parameters of the galaxies. Key words: distance scale — galaxies: distances and redshifts — galaxies: spiral

This paper explores the adherence of 47 extreme late-type galaxies to the B- and V-band Tully-Fisher relations defined by a sample of local calibrators. In both bands we find the mean luminosity at a given line width for extreme late-type spirals to lie below that predicted by standard Tully-Fisher relations. While many of the extreme late-type spirals do follow the Tully-Fisher relation to within our observational uncertainties, most of these galaxies lie below the normal, linear Tully-Fisher relation, and some are underluminous by more than 2 sigma (i.e. >1.16 magnitudes in V). This suggests a possible downward curvature of the Tully-Fisher relation for some of the smallest and faintest rotationally supported disk galaxies. This may be a consequence of the increasing prevalence of dark matter in these systems. We find the deviation from the Tully-Fisher relation to increase with decreasing luminosity and decreasing optical linear size in our sample, implying that the physically smallest and faintest spirals may be a structurally and kinematically distinct class of objects., 32 pages, 13 figures; to appear in the November AJ

Using analytic stability criteria we demonstrate that, because of their low surface mass density and large dark matter content, low surface brightness (LSB) disks are quite stable against the growth of global nonaxisymmetric modes such as bars. However, depending on their (poorly constrained) stellar velocity dispersions, they may be only marginally stable against local instabilities. We simulate a collision between an LSB and a high surface brightness (HSB) galaxy and find that, while the HSB galaxy forms a strong bar, the response of the LSB disk is milder, manifesting weaker rings and spiral features. The lack of sufficient disk self-gravity to amplify dynamical instabilities naturally explains the rarity of bars in LSB disks. The stability of LSB disks may also inhibit interaction-driven gas inflow and starburst activity in these galaxies.

The use of the Tully-Fisher (TF) relation for the determination of the Hubble Constant relies on the availability of an adequate template TF relation and of reliable primary distances. Here we use a TF template relation with the best available kinematical zero-point, obtained from a sample of 24 clusters of galaxies extending to cz ~ 9,000 km/s, and the most recent set of Cepheid distances for galaxies fit for TF use. The combination of these two ingredients yields H_not = 69+/-5 km/(s Mpc). The approach is significantly more accurate than the more common application with single cluster (e.g. Virgo, Coma) samples.

The distances to spiral galaxies of the Virgo cluster are estimated using the B-band Tully-Fisher (TF) relation, and the three-dimensional structure of the cluster is studied. The analysis is made for a complete spiral sample taken from the Virgo Cluster catalog of Binggeli, Sandage, & Tammann. The sample contains virtually all spiral galaxies down to M -->BT=-15 mag at 40 Mpc. A careful examination is made of the selection effect and errors of the data. We estimate distance to 181 galaxies, among which distances to 89 galaxies are reasonably accurate. We compare these distances to those obtained by other authors on a galaxy-by-galaxy basis. We find reasonable consistency of the Tully-Fisher distance among various authors. In particular, it is found that the discrepancy in the distance among the different analyses with different data is about 15%, when good H I and photometric data are available. We clarify that the different results on the Virgo distance among authors arise from the choice of the sample and interpretation of the data. We confirm that the Tully-Fisher relation for the Virgo cluster shows an unusually large scatter ? = 0.67 mag, compared to that for other clusters. We conclude that this scatter is not due to the intrinsic dispersion of the Tully-Fisher relation, but due to a large depth effect of the Virgo cluster, which we estimate to be extended from 12 Mpc to 30 Mpc. The distribution of H I-deficient galaxies is concentrated at around 14-20 Mpc, indicating the presence of a core at this distance, and this agrees with the distance estimated for M87 and other elliptical galaxies with other methods. We show also that the spatial number density of spiral galaxies takes a peak at this distance, while a simple average of all spiral galaxy distances gives 20 Mpc. The fact that the velocity dispersion of galaxies takes a maximum at 14-18 Mpc lends an additional support for the distance to the core. These features cannot be understood if the large scatter of the TF relation is merely due to the intrinsic dispersion. The structure of the Virgo Cluster we infer from the Tully-Fisher analysis looks like a filament which is familiar to us in a late phase of structure formation in the pancake collapse in hierarchical clustering simulations. This Virgo filament lies almost along the line of sight, and this is the origin that has led a number of authors to much confusion in the Virgo distance determinations. We show that the M87 subcluster is located around 15-18 Mpc, and it consists mainly of early-type type spiral galaxies in addition to elliptical and S0 galaxies. There are very few late-type spiral galaxies in this subcluster. The spiral rich M49 subcluster consists of a mixture of all types of spiral galaxies and is located at about 22 Mpc. The two other known clouds, W and M, are located at about 30-40 Mpc and undergo infall toward the core. The M cloud contains few early type spirals. We cannot discriminate, however, whether these subclusters or clouds are isolated aggregates or merely parts of filamentary structure. Finally, we infer the Hubble constant to be 82 ? 10 km s-1 Mpc-1.

Using the near infrared fluxes of local galaxies derived from COBE/DIRBE J(1.25 $\mu$m) K (2.2 $\mu$m) \& L (3.5 $\mu$m) band maps and published Cepheid distances, we construct Tully-Fisher (TF) diagrams for the nearby galaxies. The measured dispersions in these luminosity-linewidth diagrams are remarkably small: $\sigma_J = 0.09$ magnitudes, $\sigma_K = 0.13$ magnitudes, and $\sigma_L = 0.20$ magnitudes. For the J and K bands, Monte Carlo simulations give a 95\% confidence interval upper limit on the true scatter in the T-F diagram of $\sigma_J \le 0.35$ and $\sigma_K \le 0.45$. We determine Milky Way's luminosity and place it in the T-F diagram by fitting a bar plus ``standard'' values of its size and circular speed (Sun-Galactic center distance $R_0 = 8.5 \kpc$ and $\Theta_0 =220 \kms$), the Milky Way lies within $1.5 \sigma$ of the TF relations. We can use the TF relation and the Cepheid distances to nearby bright galaxies to constrain $R_0$ and $\Theta_0$. Alternatively, we can fix the parameters of the Galaxy to their standard values, ignore the Cepheid zero-point, and use the Tully-Fisher relation to determine the Hubble Constant directly: $H_0 = 66 \pm 12$ km/s/Mpc.

The baryonic Tully-Fisher relation (BTFR) is a valuable observational tool and a critical test of galaxy formation theory. We explore the systematic uncertainty in the slope and the scatter of the observed line width BTFR utilizing homogeneously measured, unresolved HI observations for 930 isolated galaxies. We measure a fiducial relation of $\log_{10}{M_{\rm baryon}} = 3.24\log_{10}{V_{\rm rot}}+3.21$ with observed scatter of 0.25 dex with $10^{7.4} < M_{\rm baryon} < 10^{11.3}M_{\odot}$ where $V_{\rm rot}$ is measured from 20\% HI line widths. We vary the definitions of $M_{\rm baryon}$ and $V_{\rm rot}$, the sample selection, and the linear fitting algorithm. We obtain slopes ranging from 2.64 to 3.53 and scatter measurements ranging from 0.14 to 0.41~dex, indicating a systematic uncertainty of 0.25 in the BTFR slope derived from unresolved HI line widths. We compare our fiducial slope to literature measurements, where reported slopes range from 3.0 to 4.3 and scatter is either unmeasured, immeasurable or as large as 0.4~dex. Measurements derived from unresolved HI line widths tend to produce slopes of 3.3, while measurements derived from asymptotic rotation curves tend to produce slopes of 3.9. The largest factor affecting the BTFR slope is the definition of $V_{\rm rot}$. The sample definition, the mass range, and the linear fitting algorithm also significantly affect the measured BTFR. We find that galaxies in our sample with $V_{\rm rot} < 100~\rm{km~s^{-1}}$ are consistent with the line width BTFR of more massive galaxies, but these galaxies drive most of the observed scatter. It is critical when comparing predictions to an observed BTFR that the $V_{\rm rot}$ definition, the sample selection and the fitting algorithm are similarly defined. We recommend direct statistical comparisons between data sets with commensurable properties as opposed to comparing BTFR power-law fits., Accepted by the Astrophysical Journal, figures 2 and 3 present our key results, all data are available at http://www.astro.yale.edu/jdbradford/research.html

The HI and CO components of the interstellar medium (ISM) are usually used to derive the dynamical mass M_dyn of nearby galaxies. Both components become too faint to be used as a tracer in observations of high-redshift galaxies. In those cases, the 158 $\mu$m line of atomic carbon [CII] may be the only way to derive M_dyn. As the distribution and kinematics of the ISM tracer affects the determination of M_dyn, it is important to quantify the relative distributions of HI, CO and [CII]. HI and CO are well-characterised observationally, however, for [CII] only very few measurements exist. Here we compare observations of CO, HI, and [CII] emission of a sample of nearby galaxies, drawn from the HERACLES, THINGS and KINGFISH surveys. We find that within R_25, the average [CII] exponential radial profile is slightly shallower than that of the CO, but much steeper than the HI distribution. This is also reflected in the integrated spectrum ("global profile"), where the [CII] spectrum looks more like that of the CO than that of the HI. For one galaxy, a spectrally resolved comparison of integrated spectra was possible; other comparisons were limited by the intrinsic line-widths of the galaxies and the coarse velocity resolution of the [CII] data. Using high-spectral-resolution SOFIA [CII] data of a number of star forming regions in two nearby galaxies, we find that their [CII] linewidths agree better with those of the CO than the HI. As the radial extent of a given ISM tracer is a key input in deriving M_dyn from spatially unresolved data, we conclude that the relevant length-scale to use in determining M_dyn based on [CII] data, is that of the well-characterised CO distribution. This length scale is similar to that of the optical disk., Comment: Accepted for publication in the Astronomical Journal

In a LCDM cosmology, the baryonic Tully-Fisher relation (BTFR) is expected to show significant intrinsic scatter resulting from the mass-concentration relation of dark matter halos and the baryonic-to-halo mass ratio. We study the BTFR using a sample of 118 disc galaxies (spirals and irregulars) with data of the highest quality: extended HI rotation curves (tracing the outer velocity) and Spitzer photometry at 3.6 $��$m (tracing the stellar mass). Assuming that the stellar mass-to-light ratio (M*/L) is nearly constant at 3.6 $��$m, we find that the scatter, slope, and normalization of the BTFR systematically vary with the adopted M*/L. The observed scatter is minimized for M*/L > 0.5, corresponding to nearly maximal discs in high-surface-brightness galaxies and BTFR slopes close to ~4. For any reasonable value of M*/L, the intrinsic scatter is ~0.1 dex, below general LCDM expectations. The residuals show no correlations with galaxy structural parameters (radius or surface brightness), contrary to the predictions from some semi-analytic models of galaxy formation. These are fundamental issues for LCDM cosmology., 6 pages, 2 figures, accepted for publication in ApJL

If advanced extraterrestrial civilizations choose to construct vast numbers of Dyson spheres to harvest radiation energy, this could affect the characteristics of their host galaxies. Potential signatures of such astroengineering projects include reduced optical luminosity, boosted infrared luminosity and morphological anomalies. Here, we apply a technique pioneered by Annis (1999) to search for Kardashev type III civilizations in disk galaxies, based on the predicted offset of these galaxies from the optical Tully-Fisher relation. By analyzing a sample of 1359 disk galaxies, we are able to set a conservative upper limit at 3% on the fraction of local disks subject to Dysonian astroengineering on galaxy-wide scales. However, the available data suggests that a small subset of disk galaxies actually may be underluminous with respect to the Tully-Fisher relation in the way expected for Kardashev type III objects. Based on the optical morphologies and infrared-to-optical luminosity ratios of such galaxies in our sample, we conclude that none of them stand out as strong Kardashev type III candidates and that their inferred properties likely have mundane explanations. This allows us to set a tentative upper limit at 0.3% on the fraction of Karashev type III disk galaxies in the local Universe., 13 pages, 3 figures, ApJ, in press. v.2: Typos fixed. Project homepage: http://www.astro.uu.se/~ez/hephaistos/hephaistos.html

Three tables in the paper contained errors. Table 3 contained two incorrect column headers. Table 4 presented fitting parameters in improper columns in the last two rows. Finally, the values in Table 5 were calculated using the incorrect Baryonic Tully-Fisher (BTF) relation. We present here the corrected tables, and would like to thank the vigilant readers who caught our mistakes.

We present new measures of the evolving scaling relations between stellar mass, luminosity and rotational velocity for a morphologically-inclusive sample of 129 disk-like galaxies with z_AB~1, with no significant evolution to ~0.3, \DeltaM_stellar ~ 0.04+/-0.07 dex. A clearer trend of evolution is seen in the B-band Tully-Fisher relation corresponding to a decline in luminosity of \DeltaM_B ~ 0.85+/-0.28 magnitudes at fixed velocity over the same redshift range, reflecting the changes in star formation over this period. As an illustration of the opportunities possible when gas masses are available for a sample such as ours, we show how our dynamical and stellar mass data can be used to evaluate the likely contributions of baryons and dark matter to the assembly history of spiral galaxies., Comment: 22 pages, 11 figures, Accepted for publication in the Astrophysical Journal

The Cepheid period-luminosity relation is the primary distance indicator used in most determinations of the Hubble constant. The tip of the red giant branch (TRGB) is an alternative basis. Using the new ANU SkyMapper Telescope, we calibrate the Tully Fisher relation in the I band. We find that the TRGB and Cepheid distance scales are consistent., Comment: ApJ in press 2011

We present optical long-slit rotation curves (RCs) for 304 northern Sb-Sc UGC galaxies originally selected for Tully-Fisher (TF) applications. 20% of the galaxies were observed twice or more, allowing for a proper determination of systematic errors. Various measures of maximum rotational velocity to be used as input in the TF relation are tested on the basis of their repeatability, minimization of TF scatter, and match with 21cm linewidths. The best measure of TF velocity, v2.2, is given at the location of peak rotational velocity of a pure exponential disk. Optical TF calibrations yield internal scatter comparable to, if not smaller than, the best calibrations based on single-dish 21cm radio linewidths. Even though resolved HI RCs are more extended than their optical counterpart, a tight match between optical and radio linewidths exists since the bulk of the HI surface density is enclosed within the optical radius. We model the 304 RCs presented here and a sample of 958 curves from Mathewson etal. (1992) with various fitting functions. An arctan function provides an adequate simple fit (not accounting for non-circular motions and spiral arms). More elaborate, empirical models may yield a better match at the expense of strong covariances. We caution against physical or "universal" parameterizations for TF applications. (abridged), 39 pages, 19 eps figures, 7 tables, 3 appendices. To be published in AJ (Dec. 97 issue). Appendix A is 55 pages long; only the first 3 pages are shown. The appendices and 3 tables were abridged and will be fully released in the AAS CD-ROM Series

We use Monte Carlo realizations of halo formation histories and a spherical accretion model to calculate the expected scatter in the velocity dispersions of galactic halos of a given mass due to differences in their formation times. Assuming that the rotational velocity of a spiral galaxy is determined by the velocity dispersion of its halo and that its luminosity is related to its total baryonic mass, this scatter translates to a minimum intrinsic scatter in the Tully-Fisher relation. For popular cosmological models we find that the scatter due to variations in formation histories is by itself greater than allowed by observations. Unless halos of spiral galaxies formed at high redshift (z>1) and did not later accrete any significant amount of mass, the Tully-Fisher relation is not likely to be the direct result of cosmological initial conditions but rather a consequence of a subsequent feedback process., 14 pages, uuencoded compressed Postscript, 2 figures included

We investigated the possible influence on the Tully-Fisher relation of active massive star formation in IRAS galaxies, in order to estimate the contribution of star formation to their near-infrared luminosity. We observed 60 galaxies from the infrared complete so-called IRAS Minisurvey sample in the 21 cm H1 line at Arecibo, determined the near-infrared (H-band) Tully-Fisher relation for the 36 objects in the sample we judged to be usable for this purpose, and compared this relation with that of optically selected normal galaxies. The results show no significant enhancement of the near-infrared luminosities of the IRAS Minisurvey galaxies compared to those of the optically selected normal glaxies. From these results we inferred that in the minisurvey galaxies the average contribution of the active massive star formation to the total near-infrared luminosity is less and that exponential decay times for the starbursts occurring in the Minisurvey galaxies are of the order of 10 Myr. The Tully-Fisher relation shows one exceptional galaxy (IRAS 03565+2139) with an about 25 times higher luminosity than average for its rotational velocity.

We examine the precision of the Tully-Fisher relation (TFR) using a sample of galaxies in the Coma region of the sky, and find that it is good to 5% or better in measuring relative distances. Total magnitudes and disk axis ratios are derived from H and I band surface photometry, and Arecibo 21 cm profiles define the rotation speeds of the galaxies. Using 25 galaxies for which the disk inclination and 21 cm width are well defined, we find an rms deviation of 0.10 mag from a linear TFR with dI/d(log W(sub c)) = -5.6. Each galaxy is assumed to be at a distance proportional to its redshift, and an extinction correction of 1.4(1-b/a) mag is applied to the total I magnitude. The measured scatter is less than 0.15 mag using milder extinction laws from the literature. The I band TFR scatter is consistent with measurement error, and the 95% CL limits on the intrinsic scatter are 0-0.10 mag. The rms scatter using H band magnitudes is 0.20 mag (N = 17). The low width galaxies have scatter in H significantly in excess of known measurement error, but the higher width half of the galaxies have scatter consistent with measurement error. The H band TFR slope may be as steep as the I band slope. As the first applications of this tight correlation, we note the following: (1) the data for the particular spirals commonly used to define the TFR distance to the Coma cluster are inconsistent with being at a common distance and are in fact in free Hubble expansion, with an upper limit of 300 km/s on the rms peculiar line-of-sight velocity of these gas-rich spirals; and (2) the gravitational potential in the disks of these galaxies has typical ellipticity less than 5%. The published data for three nearby spiral galaxies with Cepheid distance determinations are inconsistent with our Coma TFR, suggesting that these local calibrators are either ill-measured or peculiar relative to the Coma Supercluster spirals, or that the TFR has a varying form in different locales.

We explore the known dependence of the slope of the Tully-Fisher (TF) relation on observational wavelength using a large multifrequency galaxy data-base. We confirm that (1) in the infrared the slope of the TF relation is close to the value expected for constant mass-to-light ratio, while in the visible it increases with mass. Equivalently we show that the infrared luminosity is a good tracer of the dynamical mass in galaxies, whereas the fraction of blue light decreases with increasing mass. (2) B-H increases with mass (H luminosity) for galaxies of a given Hubble type and, at fixed H luminosity, it is larger in early morphological types. (3) The present star-formation rate and the H I content per unit mass both decrease with increasing dynamical mass

A Tully-Fisher analysis is carried out for a complete sample of spiral galaxies in the Virgo Cluster with the use of newly obtained accurate photometry data. We present the evidence that spiral galaxies in the Virgo Cluster are distributed in an elongated region, like a filament, which extends from 13 to 30 Mpc almost along the line of sight (offset 6° toward SSW) with the maximum of the density distribution at around 15 Mpc. This explains the discrepancy in the distance modulus and the dispersion among various authors who carried out Tully-Fisher analyses for the Virgo Cluster

We describe a distance indicator for spiral galaxies using detailed rotation curves derived from Hα velocity fields and I band CCD photometry. Two-dimensional velocity fields are obtained with an imaging Fabry-Perot spectrometer, with a velocity accuracy of better than 10 km/s. Rotation curves, based upon rotating disks geometries, are fit to these velocity fields. We present the I band photometry profiles, and the individual rotation curves for 75 galaxies. The extracted circular velocity is combined with I band magnitudes to form a Tully-Fisher relation, with a scatter of ∼0 m 25-0 m 3 mag

Several aspects of using the Tully-Fisher relation to estimate magnitudes and distances are examined, in particular the effect of the luminosity function on the theoretical estimation of regression parameters, unbiased estimates of absolute magnitude, and the Malmquist bias of field galaxies. With respect to observations of clusters of galaxies, if the limiting absolute magnitude is close to or brighter than the Schecter magnitude M * there is a significant difference in the slopes and offsets of the regression of magnitude upon log (line width) as calculated from Gaussian and Schecter functions

Optical CCD and 21 cm H I data are combined here via the Tully-Fisher relation to study the Galactic extinction in the V an I bands over an angular scale of a few arcmin at absolute Galactic latitudes between 2 and 16 deg. Extinctions in V and I bands are found to be linearly correlated with A(I) about 0.58 A(V), with no noticeable environmental dependence and consistent with existing results of Galactic reddening. There is a large scatter in the simple linear relation with csc /b/, confirming the existence of 'holes' and patches at low Galactic latitudes. The mean correlation between Galactic extinction and H I column density over a comparable angular scale is also found to be consistent with those at high latitudes over large angular scales. Correlation is also found between optical extinction and the IRAS 100 micron sky brightness, and this sky brightness is only slightly worse than H I column density as an indicator for optical extinction.

The velocity field in the Local Supercluster (LS) is studied on the basis of a newly compiled data set of peculiar velocities of 306 spiral galaxies as well as two well-known samples by Aaronson et al. (194 spirals) and by Faber et al. (400 ellipticals). Our sample is the largest one of spiral galaxies available at present with distance estimates as good as those for the sample of Aaronson et al. Galaxy distances in our sample are determined in this study using the Tully-Fisher relation

Photometry is presented for spiral galaxies in five clusters of galaxies in the direction of the Perseus-Pisces supercluster. The 21 cm observations of these galaxies by Giovanelli et al. (1986, AJ, 92) are employed to measure distances of these clusters by means of the Tully-Fisher relation. Most of these are in fact more distant than the supercluster and have peculiar velocities averaging -400 km/s