The Photometric and Kinematic Structure of Face‐on Disk Galaxies. I. Sample Definition, Hα Integral Field Spectroscopy, and H
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Andersen, David R.; Bershady, Matthew A.; Sparke, Linda S.; Gallagher, John S.; Wilcots, Eric M.; Driel, W. van; Monnier-Ragaigne, D.

doi:10.1086/506609

Cited by 44 publications

(54 citation statements)

References 67 publications

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“…The tightest fit is found when normalizing the radius with the Hi radius, R HI , defined as the radius where Σ Hi = 1 M pc −2 . In Martinsson (2011), we also found another tight relation between the total Hi mass (M HI ) and the Hi diameter (D HI = 2R HI ), log (M HI ) = 1.72 log (D HI ) + 6.92, (Andersen et al 2006). The total Hi mass (M HI ), Hi diameter (D HI ) and maximum Hi mass surface density (Σ max HI ) are calculated using relations derived in where M HI is the mass in units of solar masses and D HI is measured in kpc.…”

Section: Atomic Gas Mass Surface Densitysupporting

confidence: 63%

“…Direct kinematic measurements of the disk inclination has been proven to be difficult for our nearly-face-on galaxies Paper VI;Andersen & Bershady 2013), and we have adopted inclinations using the inverse Tully-Fisher relation (Paper VI). The uncertainties from these estimated inclinations, mainly introduced as systematic errors in the observed circular speed measurements, are again expected to be random for the sample.…”

Section: Uncertainties and Assumptionsmentioning

confidence: 99%

“…Typically, a threepointing dither pattern was followed, designed to fully sample the 72 × 71 field-of-view of SparsePak. The reduction of these data, such as basic data reduction, spectral extraction and wavelength calibration, follows methods described in Andersen et al (2006), and will be described in a forthcoming paper.…”

Section: Introductionmentioning

confidence: 99%

“…The Hα kinematics are measured in a similar way as the [Oiii] kinematics (Paper VI), following Andersen et al (2006Andersen et al ( , 2008, with both single and double Gaussian line profiles fitted in a 20 Å window centered around each line. Velocities are calculated using the wavelengths of the Gaussian centroids.…”

Section: Introductionmentioning

confidence: 99%

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The DiskMass Survey

Martinsson

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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 (Σ dyn ). By subtracting our observed atomic and inferred molecular gas mass surface densities from Σ dyn , we derived the stellar mass surface densities (Σ * ), 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 (Υ * = Σ * /I K ) and adopted the radial mean (Υ * ) for each galaxy to extrapolate Σ * beyond the outermost kinematic measurement. The derived Υ * of individual galaxies are consistent with all galaxies in the sample having equal Υ * . We find a sample average and scatter of Υ * = 0.31 ± 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 maximumdisk 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 2.2h R b ) 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 F 2.2h R b = 0.57 ± 0.07, with trends of larger F 2.2h R b for more luminous and higher-surface-brightness galaxies. To enforce these being maximal, we need to scale Υ * 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-Υ * (submaximal) case, we find that the derived NFW-halo parameters have values consistent with ΛCDM 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-Υ * decompositions yield halo-concentration parameters that are too low compared to the ΛCDM simulations.

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Section: Atomic Gas Mass Surface Densitysupporting

confidence: 63%

Section: Uncertainties and Assumptionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The DiskMass Survey

Martinsson

Verheijen

Westfall

et al. 2013

A&A

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197

225

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“…The kinematics of the ionized gas in our target galaxies is derived by fitting the [Oiii]λ5007 Å emission-line profile using software developed by Andersen et al (2006Andersen et al ( , 2008. We fit both single-and double-Gaussian profiles to each line within a 20 Å window centered at the redshifted wavelength of the emission line.…”

Section: Extracting Stellar and Gas Kinematicsmentioning

confidence: 99%

The DiskMass Survey

Martinsson

Verheijen

Westfall

et al. 2013

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We present ionized-gas ([Oiii]λ5007 Å) and stellar kinematics (velocities and velocity dispersions) for 30 nearly face-on spiral galaxies out to as many as three K-band disk scale lengths (h R ). These data have been derived from PPak integral-field-unit spectroscopy from 4980−5370 Å observed at a mean resolution of λ/Δλ = 7700 (σ inst = 17 km s −1 ). These data are a fundamental product of our survey and will be used in companion papers to, e.g., derive the detailed (baryonic+dark) mass budget of each galaxy in our sample. Our presentation provides a comprehensive description of the observing strategy and data reduction, including a robust measurement and removal of shift, scale, and rotation effects in the data due to instrumental flexure. Using an in-plane coordinate system determined by fitting circular-speed curves to our velocity fields, we derive azimuthally averaged rotation curves and line-of-sight velocity dispersion (σ LOS ) and luminosity profiles for both the stars and [Oiii]-emitting gas. Along with a clear presentation of the data, we demonstrate: (1) The [Oiii] and stellar rotation curves exhibit a clear signature of asymmetric drift with a rotation difference that is 11% of the maximum rotation speed of the galaxy disk, comparable to measurements in the solar neighborhood in the Milky Way.(2) The e-folding length of the stellar velocity dispersion (h σ ) is 2h R on average, as expected for a disk with a constant scale height and mass-to-light ratio, with a scatter that is notably smaller for massive, high-surface-brightness disks in the most luminous galaxies. (3) At radii larger than 1.5h R , σ LOS tends to decline slower than the best-fitting exponential function, which may be due to an increase in the disk mass-to-light ratio, disk flaring, or disk heating by the dark-matter halo. (4) A strong correlation exists between the central vertical stellar velocity dispersion of the disks (σ z,0 ) and their circular rotational speed at 2.2h R (V OIII 2.2h R ), with a zero point indicating that galaxy disks are submaximal. Moreover, weak but consistent correlations exist between σ z,0 /V OIII 2.2h R and global galaxy properties such that disks with a fainter central surface brightness in bluer and less luminous galaxies of later morphological types are kinematically colder with respect to their rotational velocities.

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Lopsided spiral galaxies

2009

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The light distribution in the disks of many galaxies is non-axisymmetric or 'lopsided' with a spatial extent much larger along one half of a galaxy than the other, as in M101. Recent near-IR observations show that lopsidedness is common. The stellar disks in nearly 30 % of galaxies have significant lopsidedness of > 10% measured as the Fourier amplitude of the m=1 component normalized to the average value. This asymmetry is traced particularly well by the atomic hydrogen gas distribution lying in the outer parts. The lopsidedness also occurs in the nuclear regions, where the nucleus is offset with respect to the outer isophotes. The galaxies in a group environment show higher lopsidedness. The origin of lopsidedness could be due to the disk response to a tidally distorted halo, or via gas accretion. An m=1 perturbation in a disk leads to a shift in the center of mass in the disk, and this then acts as an indirect force on the original center of the disk. The disk is inherently supportive of an m=1 mode, which is a particular feature only of lopsided modes, and which makes their dynamical study interesting and challenging.The lopsidedness has a large impact on the dynamics of the galaxy, its evolution, the star formation in it, and on the growth of the central black hole and on the nuclear fueling, merging of binary black holes etc. The disk lopsidedness can be used as a diagnostic to study the halo asymmetry. This is an emerging area in galactic structure and dynamics. In this review, the observations to measure the lopsided distribution, as well as the theoretical progress made so far to understand its origin and properties, and the related open problems will be discussed.

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The Photometric and Kinematic Structure of Face‐on Disk Galaxies. I. Sample Definition, Hα Integral Field Spectroscopy, and H i Line Widths

Cited by 44 publications

References 67 publications

The DiskMass Survey

The DiskMass Survey

The DiskMass Survey

Lopsided spiral galaxies

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