Hα kinematics of the Spitzer Infrared Nearby Galaxies Survey – II

Dicaire, Isabelle; Carignan, C.; Amram, P.; Hernandez, O.; Chemin, L.; Daigle, Olivier; Denus–Baillargeon, M.-M. de; Balkowski, C.; Boselli, A.; Fathi, Kambiz; Kennicutt, Robert C.

doi:10.1111/j.1365-2966.2008.12868.x

Cited by 84 publications

(88 citation statements)

References 118 publications

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“…High-redshift galaxies are clumpier and show more irregular structures than local galaxies, further complicating the visual characterization of mergers (Elmegreen et al 2007). Kinematic classifications assume that isolated disks exhibit smooth velocity gradients whereas mergers show more asymmetric and chaotic kinematic features (Shapiro et al 2008;Dicaire et al 2008;Colina et al 2005). However, this assumption does not consider post-coalescence mergers which may also display disk-like kinematics (Bellocchi et al 2012).…”

Section: Star Formation Rate Stellar and Dynamic Massmentioning

confidence: 99%

The Most Ancient Spiral Galaxy: A 2.6-Gyr-old Disk with a Tranquil Velocity Field

Yuan

Richard

Gupta

et al. 2017

ApJ

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We report an integral-field spectroscopic (IFS) observation of a gravitationally lensed spiral galaxy A1689B11 at redshift z = 2.54. It is the most ancient spiral galaxy discovered to date and the second kinematically confirmed spiral at z 2. Thanks to gravitational lensing, this is also by far the deepest IFS observation with the highest spatial resolution (∼ 400 pc) on a spiral galaxy at a cosmic time when the Hubble sequence is about to emerge. After correcting for a lensing magnification of 7.2 ± 0.8, this primitive spiral disk has an intrinsic star formation rate of 22 ± 2 M ⊙ yr −1 , a stellar mass of 10 9.8±0.3 M ⊙ and a half-light radius of r 1/2 = 2.6 ± 0.7 kpc, typical of a main-sequence star-forming (SF) galaxy at z ∼ 2. However, the Hα kinematics show a surprisingly tranquil velocity field with an ordered rotation (V c = 200 ± 12 km s −1 ) and uniformly small velocity dispersions (V σ,mean = 23 ± 4 km s −1 and V σ,outer−disk = 15 ± 2 km s −1 ). The low gas velocity dispersion is similar to local spiral galaxies and is consistent with the classic density wave theory where spiral arms form in dynamically cold and thin disks. We speculate that A1689B11 belongs to a population of rare spiral galaxies at z 2 that mark the formation epoch of thin disks. Future observations with JWST will greatly increase the sample of these rare galaxies and unveil the earliest onset of spiral arms.

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Section: Star Formation Rate Stellar and Dynamic Massmentioning

confidence: 99%

The Most Ancient Spiral Galaxy: A 2.6-Gyr-old Disk with a Tranquil Velocity Field

Yuan

Richard

Gupta

et al. 2017

ApJ

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“…These authors also showed that the inner slope of the rotation curve of NGC 2976 is likely affected by the barlike perturbation. Numerical simulations of barred disks arrived at a similar conclusion about the impact of the bar on the inner shape of rotation curves (Valenzuela et al 2007;Dicaire et al 2008). Randriamampandry et al (2015) performed numerical simulations to determine a corrected rotation curve for another barred galaxy (NGC 3319), free from the perturbing motions induced by the bar.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric mass models of disk galaxies

Chemin

Huré

Soubiran

et al. 2016

A&A

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Mass models of galactic disks traditionally rely on axisymmetric density and rotation curves, paradoxically acting as if their most remarkable asymmetric features, such as lopsidedness or spiral arms, were not important. In this article, we relax the axisymmetry approximation and introduce a methodology that derives 3D gravitational potentials of disk-like objects and robustly estimates the impacts of asymmetries on circular velocities in the disk midplane. Mass distribution models can then be directly fitted to asymmetric line-of-sight velocity fields. Applied to the grand-design spiral M 99, the new strategy shows that circular velocities are highly nonuniform, particularly in the inner disk of the galaxy, as a natural response to the perturbed gravitational potential of luminous matter. A cuspy inner density profile of dark matter is found in M 99, in the usual case where luminous and dark matter share the same center. The impact of the velocity nonuniformity is to make the inner profile less steep, although the density remains cuspy. On another hand, a model where the halo is core dominated and shifted by 2.2−2.5 kpc from the luminous mass center is more appropriate to explain most of the kinematical lopsidedness evidenced in the velocity field of M 99. However, the gravitational potential of luminous baryons is not asymmetric enough to explain the kinematical lopsidedness of the innermost regions, irrespective of the density shape of dark matter. This discrepancy points out the necessity of an additional dynamical process in these regions: possibly a lopsided distribution of dark matter.

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“…Spectral lines from stars, neutral gas, molecular gas, and ionized gas of nearby galaxies (e.g., de Zeeuw et al 2002;Helfer et al 2003;Dicaire et al 2008;Walter et al 2008) trace galaxy dynamics out to different radii (e.g., Yun et al 1994;Aalto et al 1999), and in some cases they may reveal the evolution and interaction history of galaxies (Davis et al 2011). Emission lines from molecular gas and ionized gas are the most common tracers for a large sample of resolved galaxy kinematics out to z∼3 (e.g., Tacconi et al 2006;Förster Schreiber et al 2009;Daddi et al 2010;Gnerucci et al 2011), for which the gas traces the star-forming fuel and massive star forming regions.…”

Section: Introductionmentioning

confidence: 99%

Merger Signatures in the Dynamics of Star-Forming Gas

Hung

Hayward

Smith

et al. 2016

ApJ

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The recent advent of integral field spectrographs and millimeter interferometers has revealed the internal dynamics of many hundreds of star-forming galaxies. Spatially resolved kinematics have been used to determine the dynamical status of star-forming galaxies with ambiguous morphologies, and constrain the importance of galaxy interactions during the assembly of galaxies. However, measuring the importance of interactions or galaxy merger rates requires knowledge of the systematics in kinematic diagnostics and the visible time with merger indicators. We analyze the dynamics of star-forming gas in a set of binary merger hydrodynamic simulations with stellar mass ratios of 1:1 and 1:4. We find that the evolution of kinematic asymmetries traced by star-forming gas mirrors morphological asymmetries derived from mock optical images, in which both merger indicators show the largest deviation from isolated disks during strong interaction phases. Based on a series of simulations with various initial disk orientations, orbital parameters, gas fractions, and mass ratios, we find that the merger signatures are visible for ∼0.2-0.4 Gyr with kinematic merger indicators but can be approximately twice as long for equal-mass mergers of massive gas-rich disk galaxies designed to be analogs of z∼2-3 submillimeter galaxies. Merger signatures are most apparent after the second passage and before the black holes coalescence, but in some cases they persist up to several hundred Myr after coalescence. About 20%-60% of the simulated galaxies are not identified as mergers during the strong interaction phase, implying that galaxies undergoing violent merging process do not necessarily exhibit highly asymmetric kinematics in their star-forming gas. The lack of identifiable merger signatures in this population can lead to an underestimation of merger abundances in star-forming galaxies, and including them in samples of star-forming disks may bias the measurements of disk properties such as intrinsic velocity dispersion.

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Hα kinematics of the Spitzer Infrared Nearby Galaxies Survey – II

Cited by 84 publications

References 118 publications

The Most Ancient Spiral Galaxy: A 2.6-Gyr-old Disk with a Tranquil Velocity Field

The Most Ancient Spiral Galaxy: A 2.6-Gyr-old Disk with a Tranquil Velocity Field

Asymmetric mass models of disk galaxies

Merger Signatures in the Dynamics of Star-Forming Gas

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