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Journal ArticleDOI

The DiskMass Survey VII. The distribution of luminous and dark matter in spiral galaxies

TL;DR: In this article, the authors used measured vertical velocity dispersions of the disk stars to calculate dynamical mass surface densities (Sigma$}${dyn}$) of 30 spiral galaxies, which were carried out to test the maximum disk hypothesis and to quantify properties of their dark-matter halos.
Abstract: We present dynamically-determined rotation-curve mass decompositions of 30 spiral galaxies, which were carried out to test the maximum-disk hypothesis and to quantify properties of their dark-matter halos. We used measured vertical velocity dispersions of the disk stars to calculate dynamical mass surface densities ({$Sigma$}$_{dyn}$). By subtracting our observed atomic and inferred molecular gas mass surface densities from {$Sigma$}$_{dyn}$, we derived the stellar mass surface densities ({$Sigma$}$_{∗}$), and thus have absolute measurements of all dominant baryonic components of the galaxies. Using K-band surface brightness profiles (I$_K$), we calculated the K-band mass-to-light ratio of the stellar disks ({Upsilon}$_{∗}$ = {$Sigma$}$_{∗}$/I$_K$) and adopted the radial mean (overline${$mls$}$) for each galaxy to extrapolate {$Sigma$}$_{∗}$ beyond the outermost kinematic measurement. The derived overline${$mls$}$ of individual galaxies are consistent with all galaxies in the sample having equal {Upsilon}$_{∗}$. We find a sample average and scatter of mlab overline${$mls$}$mrab = 0.31 {plusmn} 0.07. Rotation curves of the baryonic components were calculated from their deprojected mass surface densities. These were used with circular-speed measurements to derive the structural parameters of the dark-matter halos, modeled as either a pseudo-isothermal sphere (pISO) or a Navarro-Frenk-White (NFW) halo. In addition to our dynamically determined mass decompositions, we also performed alternative rotation-curve decompositions by adopting the traditional maximum-disk hypothesis. However, the galaxies in our sample are submaximal, such that at 2.2 disk scale lengths (h$_R$) the ratios between the baryonic and total rotation curves (F$_b$$^{2.2hR}$) are less than 0.75. We find this ratio to be nearly constant between 1-6h$_R$ within individual galaxies. We find a sample average and scatter of mlab F$_b$$^{2.2hR}$mrab = 0.57 {plusmn} 0.07, with trends of larger F$_b$$^{2.2hR}$ for more luminous and higher-surface-brightness galaxies. To enforce these being maximal, we need to scale {Upsilon}$_{∗}$ by a factor 3.6 on average. In general, the dark-matter rotation curves are marginally better fit by a pISO than by an NFW halo. For the nominal-{Upsilon}$_{∗}$ (submaximal) case, we find that the derived NFW-halo parameters have values consistent with {$Lambda$}CDM N-body simulations, suggesting that the baryonic matter in our sample of galaxies has only had a minor effect on the dark-matter distribution. In contrast, maximum-{Upsilon}$_{∗}$ decompositions yield halo-concentration parameters that are too low compared to the {$Lambda$}CDM simulations. Appendix is available in electronic form at http://www.aanda.org

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Citations
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Journal ArticleDOI
TL;DR: In this paper, the authors review the key integrated, structural and kinematic parameters of the Galaxy, and point to uncertainties as well as directions for future progress, and show that the Galaxy is a luminous (L⋆) barred spiral with a central box/peanut bulge, a dominant disk, and a diffuse stellar halo.
Abstract: Our Galaxy, the Milky Way, is a benchmark for understanding disk galaxies. It is the only galaxy whose formation history can be studied using the full distribution of stars from faint dwarfs to supergiants. The oldest components provide us with unique insight into how galaxies form and evolve over billions of years. The Galaxy is a luminous (L⋆) barred spiral with a central box/peanut bulge, a dominant disk, and a diffuse stellar halo. Based on global properties, it falls in the sparsely populated “green valley” region of the galaxy color-magnitude diagram. Here we review the key integrated, structural and kinematic parameters of the Galaxy, and point to uncertainties as well as directions for future progress. Galactic studies will continue to play a fundamental role far into the future because there are measurements that can only be made in the near field and much of contemporary astrophysics depends on such observations.

1,084 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present the evolution of the structure of relaxed cold dark matter haloes in the cosmology from the Planck satellite and provide a simple fitting formula that accurately describes the evolution between redshifts z=5 to z=0 for both NFW and Einasto fits.
Abstract: We present the evolution of the structure of relaxed cold dark matter haloes in the cosmology from the Planck satellite Our simulations cover 5 decades in halo mass, from dwarf galaxies to galaxy clusters Due to the increased matter density and power spectrum normalization the concentration mass relation in the Planck cosmology has a 20 percent higher normalization at redshift z=0 compared to WMAP cosmology We confirm that CDM haloes are better described by the Einasto profile; for example, at scales near galaxy half-light radii CDM haloes have significantly steeper density profiles than implied by NFW fits There is a scatter of 02 dex in the Einasto shape parameter at fixed halo mass, adding further to the diversity of CDM halo profiles The evolution of the concentration mass relation in our simulations is not reproduced by any of the analytic models in the literature We thus provide a simple fitting formula that accurately describes the evolution between redshifts z=5 to z=0 for both NFW and Einasto fits Finally, the observed concentrations and halo masses of spiral galaxies, groups and clusters of galaxies at low redshifts are in good agreement with our simulations, suggesting only mild halo response to galaxy formation on these scales

780 citations


Cites background or result from "The DiskMass Survey VII. The distri..."

  • ...The black pentagons show observational results for spiral galaxies at redshift z ≃ 0 from the DiskMass project (Bershady et al. 2010; Martinsson et al. 2013)....

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  • ...• The observed concentrations and halo masses from NFW fits to data of spiral galaxies from the DiskMass project (Bershady et al. 2010; Martinsson et al. 2013), groups and clusters of galaxies (Ettori et al. 2010; Auger et al. 2013) are in good agreement with our simulations suggesting only mild…...

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Journal ArticleDOI
TL;DR: A correlation between the radial acceleration traced by rotation curves and that predicted by the observed distribution of baryons is reported, tantamount to a natural law for rotating galaxies.
Abstract: We report a correlation between the radial acceleration traced by rotation curves and that predicted by the observed distribution of baryons. The same relation is followed by 2693 points in 153 galaxies with very different morphologies, masses, sizes, and gas fractions. The correlation persists even when dark matter dominates. Consequently, the dark matter contribution is fully specified by that of the baryons. The observed scatter is small and largely dominated by observational uncertainties. This radial acceleration relation is tantamount to a natural law for rotating galaxies.

532 citations

Journal ArticleDOI
TL;DR: SPARC (Spitzer Photometry & Accurate Rotation Curves) as mentioned in this paper is a sample of 175 nearby galaxies with new surface photometry at 3.6 um and high-quality rotation curves from previous HI/Halpha studies.
Abstract: We introduce SPARC (Spitzer Photometry & Accurate Rotation Curves): a sample of 175 nearby galaxies with new surface photometry at 3.6 um and high-quality rotation curves from previous HI/Halpha studies. SPARC spans a broad range of morphologies (S0 to Irr), luminosities (~5 dex), and surface brightnesses (~4 dex). We derive [3.6] surface photometry and study structural relations of stellar and gas disks. We find that both the stellar mass-HI mass relation and the stellar radius-HI radius relation have significant intrinsic scatter, while the HI mass-radius relation is extremely tight. We build detailed mass models and quantify the ratio of baryonic-to-observed velocity (Vbar/Vobs) for different characteristic radii and values of the stellar mass-to-light ratio (M/L) at [3.6]. Assuming M/L=0.5 Msun/Lsun (as suggested by stellar population models) we find that (i) the gas fraction linearly correlates with total luminosity, (ii) the transition from star-dominated to gas-dominated galaxies roughly corresponds to the transition from spiral galaxies to dwarf irregulars in line with density wave theory; and (iii) Vbar/Vobs varies with luminosity and surface brightness: high-mass, high-surface-brightness galaxies are nearly maximal, while low-mass, low-surface-brightness galaxies are submaximal. These basic properties are lost for low values of M/L=0.2 Msun/Lsun as suggested by the DiskMass survey. The mean maximum-disk limit in bright galaxies is M/L=0.7 Msun/Lsun at [3.6]. The SPARC data are publicly available and represent an ideal test-bed for models of galaxy formation.

513 citations

References
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Journal ArticleDOI
TL;DR: The Two Micron All Sky Survey (2MASS) as mentioned in this paper collected 25.4 Tbytes of raw imaging data from two dedicated 1.3 m diameter telescopes located at Mount Hopkins, Arizona and CerroTololo, Chile.
Abstract: Between 1997 June and 2001 February the Two Micron All Sky Survey (2MASS) collected 25.4 Tbytes of raw imagingdatacovering99.998%ofthecelestialsphereinthenear-infraredJ(1.25 � m),H(1.65 � m),andKs(2.16 � m) bandpasses. Observations were conducted from two dedicated 1.3 m diameter telescopes located at Mount Hopkins, Arizona,andCerroTololo,Chile.The7.8sofintegrationtimeaccumulatedforeachpointontheskyandstrictquality control yielded a 10 � point-source detection level of better than 15.8, 15.1, and 14.3 mag at the J, H, and Ks bands, respectively, for virtually the entire sky. Bright source extractions have 1 � photometric uncertainty of <0.03 mag and astrometric accuracy of order 100 mas. Calibration offsets between any two points in the sky are <0.02 mag. The 2MASS All-Sky Data Release includes 4.1 million compressed FITS images covering the entire sky, 471 million source extractions in a Point Source Catalog, and 1.6 million objects identified as extended in an Extended Source Catalog.

12,126 citations


"The DiskMass Survey VII. The distri..." refers methods in this paper

  • ...…gas kinematics from SparsePak (Bershady et al. 2004, 2005), as well as 21-cm radio synthesis data from the WSRT, GMRT and VLA, nearinfrared (NIR) photometry from the Two-Micron All-Sky Survey (2MASS; Skrutskie et al. 2006) and MIPS 24-µm imaging from the Spitzer Space Telescope (hereafterSpitzer)....

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Journal ArticleDOI
TL;DR: In this article, the authors used high-resolution N-body simulations to study the equilibrium density profiles of dark matter halos in hierarchically clustering universes, and they found that all such profiles have the same shape, independent of the halo mass, the initial density fluctuation spectrum, and the values of the cosmological parameters.
Abstract: We use high-resolution N-body simulations to study the equilibrium density profiles of dark matter halos in hierarchically clustering universes. We find that all such profiles have the same shape, independent of the halo mass, the initial density fluctuation spectrum, and the values of the cosmological parameters. Spherically averaged equilibrium profiles are well fitted over two decades in radius by a simple formula originally proposed to describe the structure of galaxy clusters in a cold dark matter universe. In any particular cosmology, the two scale parameters of the fit, the halo mass and its characteristic density, are strongly correlated. Low-mass halos are significantly denser than more massive systems, a correlation that reflects the higher collapse redshift of small halos. The characteristic density of an equilibrium halo is proportional to the density of the universe at the time it was assembled. A suitable definition of this assembly time allows the same proportionality constant to be used for all the cosmologies that we have tested. We compare our results with previous work on halo density profiles and show that there is good agreement. We also provide a step-by-step analytic procedure, based on the Press-Schechter formalism, that allows accurate equilibrium profiles to be calculated as a function of mass in any hierarchical model.

9,729 citations


"The DiskMass Survey VII. The distri..." refers background in this paper

  • ...Fromnumerical N-body simulations (e.g., Navarro et al. 1997) the inner density profiles and concentrations of the dark-matter halos re predicted in the absence of baryons....

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  • ...(6) The NFW halo is parameterized by its mass (Mhalo200) within the virial radius (R200; defined as the radius of a sphere of mean interior density 200 times the critical densityρcrit=3H20/8πG) and its concentration (C) as defined in Navarro et al. (1997)....

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  • ...…into Cases Ia and IIa, which have a parameterized dark-matter halo modeled as a spherical pseudo-isothermal sphere (pISO; e.g., Ostriker & Caldwe l 1979; Schmidt 1985; Kent 1986), and Cases Ib and IIb which instead include a Navarro-Frenk-White (NFW; Navarro et al. 1997) dark-matter-halo model....

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Journal ArticleDOI
TL;DR: In this article, high-resolution N-body simulations show that the density profiles of dark matter halos formed in the standard CDM cosmogony can be fit accurately by scaling a simple universal profile.
Abstract: High resolution N-body simulations show that the density profiles of dark matter halos formed in the standard CDM cosmogony can be fit accurately by scaling a simple “universal” profile. Regardless of their mass, halos are nearly isothermal over a large range in radius, but significantly shallower than r -2 near the center and steeper than r -2 in the outer regions. The characteristic overdensity of a halo correlates strongly with halo mass in a manner consistent with the mass dependence of the epoch of halo formation. Matching the shape of the rotation curves of disk galaxies with this halo structure requires (i) disk mass-to-light ratios to increase systematically with luminosity, (ii) halo circular velocities to be systematically lower than the disk rotation speed, and (iii) that the masses of halos surrounding bright galaxies depend only weakly on galaxy luminosity. This offers an attractive explanation for the puzzling lack of correlation between luminosity and dynamics in observed samples of binary galaxies and of satellite companions of bright spiral galaxies, suggesting that the structure of dark matter halos surrounding bright spirals is similar to that of cold dark matter halos.

7,622 citations

Book ChapterDOI
01 Jan 1991
TL;DR: In this article, a reference catalogue of bright galaxies in three volumes reflects the explosive growth of extragalactic astronomy over the last 15 years and includes all galaxies with apparent diameters larger than one arc minute, magnitudes brighter than about magnitude 15.5, and redshifts not larger than 15,000 km/sec.
Abstract: This new, enlarged reference catalogue of bright galaxies in three volumes reflects the explosive growth of extragalactic astronomy over the last 15 years. With data on more than 23,000 galaxies, it includes all galaxies with apparent diameters larger than one arc minute, magnitudes brighter than about magnitude 15.5, and redshifts not larger than 15,000 km/sec, as well as many other objects of interest. Volume 1 contains the explanations and references; volumes 2 and 3 contain the catalogue proper. The catalogue gives for each galaxy, the position, names, type and luminosity class, optical diameters, optical and infrared magnitudes, various colour indices and radial velocities. The work also makes reference to papers on bright galaxies published between 1913 and 1988. This dictionary/encyclopaedia on stellar systems is intended for researchers in astronomy.

4,656 citations


"The DiskMass Survey VII. The distri..." refers methods in this paper

  • ...Distances are taken from Paper I. Integrated Hi fluxes ( ∫ S HIdV) are from tabulated values in NED, with three different sources; 1(RC3; de Vaucouleurs et al. 1991),2(HIPASS; Doyle et al. 2005), 3(Andersen et al. 2006)....

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Journal ArticleDOI
TL;DR: In this paper, the authors considered the possibility that there is not much hidden mass in galaxies and galaxy systems and proposed a modified version of the Newtonian dynamics to describe the motion of bodies in a gravitational field (of a galaxy, say).
Abstract: The author considers the possibility that there is not, in fact, much hidden mass in galaxies and galaxy systems. If a certain modified version of the Newtonian dynamics is used to describe the motion of bodies in a gravitational field (of a galaxy, say), the observational results are reproduced with no need to assume hidden mass in appreciable quantities. Various characteristics of galaxies result with no further assumptions. The basis of the modification is the assumption that in the limit of small acceleration a very low a0, the acceleration of a particle at distance r from a mass M satisfies approximately a2/a0 a MGr-2, where a0 is a constant of the dimensions of an acceleration.

3,094 citations


"The DiskMass Survey VII. The distri..." refers background in this paper

  • ...…mass-to-light ratio of the stellar component (Υ∗) until the rotation curve of the baryons approximates the amplitude of the erations (e.g., Milgrom 1983; Begeman et al. 1991; Sanders 1996; Sanders & Verheijen 1998). observed rotation curve in the inner region (the “maximum-disk…...

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