arXiv subjects

Ken-ichi Tadaki

Publications and source records attributed to Ken-ichi Tadaki.

At least 55 records · Page 3Linked to original sources

arXiv2020

Large Population of ALMA Galaxies at z>6 with Very High [OIII]88um to [CII]158um Flux Ratios: Evidence of Extremely High Ionization Parameter or PDR Deficit?

We present our new ALMA observations targeting [OIII]88um, [CII]158um, [NII]122um, and dust continuum emission for three Lyman break galaxies at z=6.0293-6.2037 identified in the Subaru/Hyper Suprime-Cam survey. We clearly detect [OIII] and [CII] lines from all of the galaxies at 4.3-11.8sigma levels, and identify multi-band dust continuum emission in two of the three galaxies, allowing us to estimate infrared luminosities and dust temperatures simultaneously. In conjunction with previous ALMA observations for six galaxies at z>6, we confirm that all the nine z=6-9 galaxies have high [OIII]/[CII] ratios of L[OIII]/L[CII]~3-20, ~10 times higher than z~0 galaxies. We also find a positive correlation between the [OIII]/[CII] ratio and the Lya equivalent width (EW) at the ~90% confidence level. We carefully investigate physical origins of the high [OIII]/[CII] ratios at z=6-9 using Cloudy, and find that high density of the interstellar medium, low C/O abundance ratio, and the cosmic microwave background attenuation are responsible to only a part of the z=6-9 galaxies. Instead, the observed high [OIII]/[CII] ratios are explained by 10-100 times higher ionization parameters or low photodissociation region (PDR) covering fractions of 0-10%, both of which are consistent with our [NII] observations. The latter scenario can be reproduced with a density bounded nebula with PDR deficit, which would enhance the Lya, Lyman continuum, and C+ ionizing photons escape from galaxies, consistent with the [OIII]/[CII]-Lya EW correlation we find.

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arXiv2020

A non-corotating gas component in an extreme starburst at z=4.3

We report the detection of a non-corotating gas component in a bright unlensed submillimeter galaxy at z=4.3, COSMOS-AzTEC-1, hosting a compact starburst. ALMA 0.17 and 0.09 arcsec resolution observations of [CII] emission clearly demonstrate that the gas kinematics is characterized by an ordered rotation. After subtracting the best-fit model of a rotating disk, we kinematically identify two residual components in the channel maps. Both observing simulations and analysis of dirty images confirm that these two subcomponents are not artificially created by noise fluctuations and beam deconvolution. One of the two has a velocity offset of 200 km/s and a physical separation of 2 kpc from the primary disk and is located along the kinematic minor axis of disk rotation. We conclude that this gas component is falling into the galaxy from a direction perpendicular to the disk rotation. The accretion of such small non-corotating gas components could stimulate violent disk instability, driving radial gas inflows into the center of galaxies and leading to formation of in-situ clumps such as identified in dust continuum and CO. We require more theoretical studies on high gas fraction mergers with mass ratio of 1:>10 to verify this process.

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arXiv2019

A Radio-to-millimeter Census of Star-forming Galaxies in Protocluster 4C~23.56 at z = 2.5 : Global and local gas kinematics

We present a study of the gas kinematics of star-forming galaxies associated with protocluster 4C 23.56 at $z=2.49$ using $0''.4$ resolution CO (4-3) data taken with ALMA. Eleven H$α$ emitters (HAEs) are detected in CO (4-3), including six HAEs that were previously detected in CO (3-2) at a coarser angular resolution. The detections in both CO lines are broadly consistent in the line widths and the redshifts, confirming both detections. With an increase in the number of spectroscopic redshifts, we confirm that the protocluster is composed of two merging groups with a total halo mass of $\log{(M_{\rm cl}/M_{\odot})} =13.4-13.6$, suggesting that the protocluster would evolve into a Virgo-like cluster ($>10^{14} M_{\odot}$). We compare the CO line widths and the CO luminosities with galaxies in other (proto)clusters ($n_{\rm gal}=91$) and general fields ($n_{\rm gal}=80$) from other studies. The 4C23.56 protocluster galaxies have CO line widths and luminosities comparable to other protocluster galaxies on average. On the other hand, the CO line widths are on average broader by $\approx50\%$ compared to field galaxies, while the median CO luminosities are similar. The broader line widths can be attributed to both effects of unresolved gas-rich mergers and/or compact gas distribution, which is supported by our limited but decent angular resolution observations and the size estimate of three galaxies. Based on these results, we argue that gas-rich mergers may play a role in the retention of the specific angular momentum to a value similar to that of field populations during cluster assembly, though we need to verify this with a larger number of samples.

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arXiv2019

The Evolution and Origin of Ionized Gas Velocity Dispersion from $z\sim2.6$ to $z\sim0.6$ with KMOS$^{\rm 3D}$

We present the $0.6<z<2.6$ evolution of the ionized gas velocity dispersion in 175 star-forming disk galaxies based on data from the full KMOS$^{\rm 3D}$ integral field spectroscopic survey. In a forward-modelling Bayesian framework including instrumental effects and beam-smearing, we fit simultaneously the observed galaxy velocity and velocity dispersion along the kinematic major axis to derive the intrinsic velocity dispersion $σ_0$. We find a reduction of the average intrinsic velocity dispersion of disk galaxies as a function of cosmic time, from $σ_0\sim45$ km s$^{-1}$ at $z\sim2.3$ to $σ_0\sim30$ km s$^{-1}$ at $z\sim0.9$. There is substantial intrinsic scatter ($σ_{σ_0, {\rm int}}\approx10$ km s$^{-1}$) around the best-fit $σ_0-z$-relation beyond what can be accounted for from the typical measurement uncertainties ($δσ_0\approx12$ km s$^{-1}$), independent of other identifiable galaxy parameters. This potentially suggests a dynamic mechanism such as minor mergers or variation in accretion being responsible for the scatter. Putting our data into the broader literature context, we find that ionized and atomic+molecular velocity dispersions evolve similarly with redshift, with the ionized gas dispersion being $\sim10-15$ km s$^{-1}$ higher on average. We investigate the physical driver of the on average elevated velocity dispersions at higher redshift, and find that our galaxies are at most marginally Toomre-stable, suggesting that their turbulent velocities are powered by gravitational instabilities, while stellar feedback as a driver alone is insufficient. This picture is supported through comparison with a state-of-the-art analytical model of galaxy evolution.

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arXiv2019

Testing Star Formation Laws on Spatially Resolved Regions in a $z \approx 4.3$ Starburst Galaxy

We probe the star formation properties of the gas in AzTEC-1 in the COSMOS field, one of the best resolved and brightest starburst galaxies at $z \approx 4.3$, forming stars at a rate > 1000 $\mathrm{M_{\odot}}\,\mathrm{yr^{-1}}$. Using recent ALMA observations, we study star formation in the galaxy nucleus and an off-center star-forming clump and measure a median star formation rate (SFR) surface density of $Σ^{\mathrm{nucleus}}_{\mathrm{SFR}} = 270\pm54$ and $Σ^{\mathrm{sfclump}}_{\mathrm{SFR}} = 170\pm38\,\mathrm{M_{\odot}}\,\mathrm{yr}^{-1}\,\mathrm{kpc}^{-2}$, respectively. Following the analysis by Sharda et al. (2018), we estimate the molecular gas mass, freefall time and turbulent Mach number in these regions to predict $Σ_{\mathrm{SFR}}$ from three star formation relations in the literature. The Kennicutt-Schmidt (Kennicutt 1998, KS) relation, which is based on the gas surface density, underestimates the $Σ_{\mathrm{SFR}}$ in these regions by a factor 2-3. The $Σ_{\mathrm{SFR}}$ we calculate from the single-freefall model of Krumholz et al. 2012 (KDM) is consistent with the measured $Σ_{\mathrm{SFR}}$ in the nucleus and the star-forming clump within the uncertainties. The turbulence-regulated star formation relation by Salim et al. 2015 (SFK) agrees slightly better with the observations than the KDM relation. Our analysis reveals that an interplay between turbulence and gravity can help sustain high SFRs in high-redshift starbursts. It can also be extended to other high- and low-redshift galaxies thanks to the high angular resolution and sensitivity of ALMA observations.

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arXiv2019

A spectroscopic study of a rich cluster at z=1.52 with Subaru $\&$ LBT: the environmental impacts on the mass-metallicity relation

We present the results of our near-infrared (NIR) spectroscopic observations of a rich cluster candidate around a radio galaxy at $z=1.52$ (4C65.22) with Subaru/MOIRCS and LBT/LUCI. We observed 71 galaxies mostly on the star-forming main sequence selected by our previous broad-band (photo-$z$) and narrow-band H$α$ imaging observation in this cluster environment. We successfully confirmed the redshifts of 39 galaxies, and conclude that this is a gravitationally bound, real cluster at $z=1.517$. Our spectroscopic data also suggest a hint of large-scale filaments or sheet-like three-dimensional structures crossing at the highest-density cluster core. By stacking the spectra to derive their average interstellar medium (ISM) gas-phase metallicity based on the [NII]/H$α$ emission line flux ratio, we find that the mass-metallicity relation (MZR) in the 4C65.22 cluster environment is consistent with that of H$α$-selected field galaxies at similar redshifts. Our results suggest that the environmental impacts on the MZR is small at high redshifts, but a larger sample of high-$z$ clusters and their member galaxies is still required to fully address the effect of environment as well as its cluster-cluster variation.

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arXiv2019

Extended star-forming region within galaxies in a dense proto-cluster core at z=2.53

At $z\sim2$, star-formation activity is thought to be high even in high-density environments such as galaxy clusters and proto-clusters. One of the critical but outstanding issues is if structural growth of star-forming galaxies can differ depending on their surrounding environments. In order to investigate how galaxies grow their structures and what physical processes are involved in the evolution of galaxies, one requires spatially resolved images of not only stellar components but also star-forming regions within galaxies. We conducted the Adaptive Optics(AO)-assisted imaging observations for star-forming galaxies in a dense proto-cluster core at $z=2.53$ with IRCS and AO188 mounted on the Subaru Telescope. A combination of AO and narrow-band filters allows us to obtain resolved maps of H$α$-emitting regions with an angular resolution of 0.1--0.2~arcsec, which corresponds to $\sim1$ kpc at $z\sim2.5$. Based on stacking analyses, we compare radial profiles of star-forming regions and stellar components and find that the star-forming region of a sub-sample with $\rm log(M_*/M_\odot)\sim10-11$ is more extended than the stellar component, indicating the inside-out growth of the structure. This trend is similar to the one for star-forming galaxies in general fields at $z=2-2.5$ obtained with the same observational technique. Our results suggest that the structural evolution of star-forming galaxies at $z=2-2.5$ is mainly driven by internal secular processes irrespective of surrounding environments.

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arXiv2019

CNO emission of an unlensed submillimeter galaxy at z=4.3

We present the results from ALMA observations of [NII]205 micron, [CII]158 micron, and [OII]88 micron lines in an unlensed submillimeter galaxy at z=4.3, COSMOS-AzTEC-1, hosting a compact starburst core with an effective radius of 1 kpc. The [CII] and [NII] emission are spatially-resolved in 0.3 arcsec-resolution (1 kpc in radius). The kinematic properties of the [NII] emission are consistent with those of the CO(4-3) and [CII] emission, suggesting that the ionized gas feels the same gravitational potential as the associated molecular gas and photodissociation regions (PDRs). On the other hand, the spatial extent is different among the lines and dust continuum: the [CII] emitting gas is the most extended and the dust is the most compact, leading to a difference of the physical conditions in the interstellar medium. We derive the incident far-ultraviolet flux and the hydrogen gas density through PDR modeling by properly subtracting the contribution of ionized gas to the total [CII] emission. The observed [CII] emission is likely produced by dense PDRs with nH(PDR)=10^(5.5-5.75) cm^-3 and G0=10^(3.5-3.75) in the central 1 kpc region and nH(PDR)=10^(5.0-5.25) cm^-3 and G0=10^(3.25-3.5) in the central 3 kpc region. We have also successfully measured the line ratio of [OIII/[NII] in the central 3 kpc region of COSMOS-AzTEC-1 at z=4.3, which is the highest redshift where both nitrogen and oxygen lines are detected. Under the most likely physical conditions, the measured luminosity ratio of L([OIII])/L([NII])=6.4+-2.2 indicates a near solar metallicity with Zgas=0.7-1.0 Zsol, suggesting a chemically evolved system at z=4.3.

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arXiv2019

ALMA twenty-six arcmin$^2$ survey of GOODS-S at one-millimeter (ASAGAO): Near-infrared-dark faint ALMA sources

We report detections of two 1.2 mm continuum sources ($S_\mathrm{1.2mm}$ ~ 0.6 mJy) without any counterparts in the deep $H$- and/or $K$-band image (i.e., $K$-band magnitude $\gtrsim$ 26 mag). These near-infrared-dark faint millimeter sources are uncovered by ASAGAO, a deep and wide-field ($\simeq$ 26 arcmin$^2$) Atacama Large Millimeter/submillimeter Array (ALMA) 1.2 mm survey. One has a red IRAC (3.6 and 4.5 $μ$m) counterpart, and the other has been independently detected at 850 and 870 $μ$m using SCUBA2 and ALMA Band 7, respectively. Their optical to radio spectral energy distributions indicate that they can lie at $z \gtrsim$ 3-5 and can be in the early phase of massive galaxy formation. Their contribution to the cosmic star formation rate density is estimated to be ~ 1 $\times$ 10$^{-3}$ $M_\odot$ yr$^{-1}$ Mpc$^{-3}$ if they lie somewhere in the redshift range of $z$ ~ 3-5. This value can be consistent with, or greater than that of bright submillimeter galaxies ($S_\mathrm{870μm}>$ 4.2 mJy) at $z$ ~ 3-5. We also uncover 3 more candidates near-infrared-dark faint ALMA sources without any counterparts ($S_\mathrm{1.2mm}$ ~ 0.45-0.86 mJy). These results show that an unbiased ALMA survey can reveal the dust-obscured star formation activities, which were missed in previous deep optical/near-infrared surveys.

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arXiv2019

Environmental impacts on molecular gas in protocluster galaxies at z~2

We present the results from ALMA CO(3-2) observations of 66 Halpha-selected galaxies in three protoclusters around radio galaxies, PKS1138-262 (z=2.16) and USS1558-003 (z=2.53), and 4C23.56 (z=2.49). The pointing areas have an overdensity of ~100 compared to a mean surface number density of galaxies in field environments. We detect CO emission line in 16 star-forming galaxies, including previously published six galaxies, to measure the molecular gas mass. In the stellar mass range of 10.5 11.0 are comparable in mass to the scaling relation, or smaller. Our results suggest that the environmental effects on gas properties are mass-dependent: in high-density environments, gas accretion through cosmic filaments is accelerated in less massive galaxies while this is suppressed in the most massive system.

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arXiv2018

Galaxy mergers up to z<2.5 I : The star formation properties of merging galaxies at separations 3-15 kpc

We present a study of the influence of galaxy mergers on star formation at 0.3 10) are star-bursting (i.e., with SFR above the main sequence of star-forming galaxies by >0.5 dex). Merging galaxies which include galaxies with lower masses show a higher fraction of star-bursting galaxies (20%). The low fraction of star-bursting merging galaxies in this sample suggests that at galaxy nuclei separations of 3-15 kpc merging galaxies are still in a early stage and are yet to reach the maximum level of star formation activity. Furthermore, the level of star formation enhancement and its duration could be arguably reduced compared to local mergers, as shown by simulations of high-z mergers, and might also depend on the physical properties (such as stellar mass and gas fraction) of the merging galaxies. Finally, we compare the specific SFR between merging galaxies. Our results suggest that, as the mass of the merging galaxies increases, the star formation activity in the less massive member in the merger suffers a more dramatic impact than its companion galaxy.

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arXiv2018

Identification of variability in recent star formation histories of local galaxies based on H$α$/UV ratio

Because the timescale of H$α$ emission (several tens of Myr) following star formation is significantly shorter than that of UV radiation (a few hundred Myr), the H$α$/UV flux ratio provides insight on the star formation histories (SFHs) of galaxies on timescales shorter than $\sim100$ Myr. We present H$α$/UV ratios for galaxies at $z=$ 0.02--0.1 on the familiar star-forming main sequence based on the AKARI-GALEX-SDSS archive dataset. The data provide us with robust measurements of dust-corrected SFRs in both H$α$ and UV for 1,050 galaxies. The results show a correlation between the H$α$/UV ratio and the deviation from the main sequence in the sense that galaxies above/below the main sequence tend to have higher/lower H$α$/UV ratios. This trend increases the dispersion of the main sequence by 0.04 dex (a small fraction of the total scatter of 0.36 dex), suggesting that diversity of recent SFHs of galaxies has a direct impact on the observed main sequence scatter. We caution that the results suffer from incompleteness and a selection bias which may lead us to miss many sources with high H$α$/UV ratios, this could further increase the scatter from SFHs in the star-forming main sequence.

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arXiv2018

MAHALO Deep Cluster Survey II. Characterizing massive forming galaxies in the Spiderweb protocluster at z=2.2

This paper is the second in a series presenting the results of our deep H$α$-line survey towards protoclusters at $z>2$, based on narrow-band imaging with the Subaru Telescope. This work investigates massive galaxies in a protocluster region associated with a radio galaxy (PKS 1138$-$262), the Spiderweb galaxy, at $z=2.2$. Our 0.5 mag deeper narrow-band imaging than previous surveys collects a total of 68 H$α$ emitters (HAE). 17 out of the 68 are newly discovered protocluster members. First, a very high characteristic stellar mass of M$_\star^\ast=10^{11.73}$ M$_\odot$ is measured from a Schechter function fit to the mass distribution of HAEs. Together with the Chandra X-ray data, we find that four out of six massive HAEs (M$_\star>10^{11}$ M$_\odot$) show bright X-ray emission, suggesting that they host active galactic nuclei (AGNs). Their mass estimates, therefore, would be affected by the nuclear emission from AGNs. Notably, the X-ray detected HAEs are likely positioned near the boundary between star-forming and quiescent populations in the rest-frame $UVJ$ plane. Moreover, our deep narrow-band data succeed in probing the bright H$α$ (+[Nii]) line nebula of the Spiderweb galaxy extending over $\sim100$ physical kpc. These results suggest that the massive galaxies in the Spiderweb protocluster are on the way to becoming the bright red sequence objects seen in local galaxy clusters, where AGNs might play an essential role in their quenching processes. Though a more statistical database is needed to build a general picture.

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arXiv2018

A gravitationally unstable gas disk of a starburst galaxy 12 billion years ago

Submillimeter bright galaxies in the early Universe are vigorously forming stars at ~1000 times higher rate than the Milky Way. A large fraction of stars is formed in the central 1 kiloparsec region, that is comparable in size to massive, quiescent galaxies found at the peak of the cosmic star formation history, and eventually the core of giant elliptical galaxies in the present-day Universe. However, the physical and kinematic properties inside a compact starburst core are poorly understood because dissecting it requires angular resolution even higher than the Hubble Space Telescope can offer. Here we report 550 parsec-resolution observations of gas and dust in the brightest unlensed submillimeter galaxy at z=4.3. We map out for the first time the spatial and kinematic structure of molecular gas inside the heavily dust-obscured core. The gas distribution is clumpy while the underlying disk is rotation-supported. Exploiting the high-quality map of molecular gas mass surface density, we find a strong evidence that the starburst disk is gravitationally unstable, implying that the self-gravity of gas overcomes the differential rotation and the internal pressure by stellar radiation feedback. The observed molecular gas would be consumed by star formation in a timescale of 100 million years, that is comparable to those in merging starburst galaxies. Our results suggest that the most extreme starburst in the early Universe originates from efficient star formation due to a gravitational instability in the central 2 kpc region.

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arXiv2018

ALMA 26 Arcmin$^{2}$ Survey of GOODS-S at One-millimeter (ASAGAO): Average Morphology of High-$z$ Dusty Star-Forming Galaxies is an Exponential-Disk ($n \simeq 1$)

We present morphological properties of dusty star-forming galaxies at z=1-3 determined with high-resolution (FWHM~0"19) Atacama Large Milllimeter/submilimeter Array (ALMA) 1-mm band maps of our ASAGAO survey covering a 26-arcmin^2 area in GOODS-S. In conjunction with the ALMA archival data, the present sample consists of 42 ALMA sources with a wide rest-frame far-infrared (FIR) luminosity L_FIR range of ~10^11-10^13 Lo. To obtain an average rest-frame FIR profile, we perform individual measurements and careful stacking of the ALMA sources using the uv-visibility method that includes positional-uncertainty and smoothing-effect evaluations through Monte-Carlo simulations. We find that the dusty star-forming galaxies have the average FIR-wavelength Sersic index and effective radius of n_FIR=1.2+/-0.2 and R_e,FIR=1.0-1.3 kpc, respectively, additionally with a point source at the center, indicative of the existence of AGN. The average FIR profile agrees with a morphology of an exponential-disk clearly distinguished from a spheroidal profile (Sersic index of 4). We also examine the rest-frame optical Sersic index n_opt and effective radius R_e,opt with the deep Hubble Space Telescope (HST) images. Interestingly, we obtain n_opt=0.9+/-0.3 (~n_FIR) and R_e,opt=3.2+/-0.6 kpc (>R_e,FIR), suggesting that the FIR-emitting disk is embedded within a larger stellar disk. The rest-frame UV and FIR data of HST and ALMA provide us a radial surface density profile of the total star-formation rate (SFR), where the FIR SFR dominates over the UV SFR at the center. Under the simple assumption of a constant SFR, a compact stellar distribution found in z~1-2 compact quiescent galaxies (cQGs) is well reproduced, while a spheroidal stellar morphology of cQGs (n_opt=4) cannot, suggestive of other important mechanisms such as dynamical dissipation.

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arXiv2018

The Fraction of Active Galactic Nuclei in the USS 1558-003 Protocluster at z = 2.53

The incidence of Active Galactic Nuclei (AGN) with local environment is a potentially valuable probe of the mechanisms that trigger and provide fuel for accretion onto supermassive black holes. While the correlation between AGN fraction and environment has been well-studied in the local universe, AGN fractions have been measured for relatively few dense environments at high redshift. In this paper we present a measurement of the X-ray AGN fraction in the USS 1558-003 protocluster associated with the z=2.53 radio galaxy 4C-00.62. Our measurement is based on a 100ks Chandra observation, follow-up spectroscopy from the Multi-Object Double Spectrograph on the Large Binocular Telescope, and broad and narrow band photometry. These data are sensitive to AGN more luminous than $L_{X}>2\times10^{43}$ erg s$^{-1}$ in the rest-frame hard X-ray band (2-10 keV). We have identified two X-ray AGN at the redshift of USS 1558-003, one of which is the radio galaxy. We have determined that $2.0^{+2.6}_{-1.3}$% of the H$α$ emitters in the protocluster are X-ray AGN. Unlike most other high-redshift cluster progenitors studied with similar techniques, USS 1558-003 does not have a significantly higher fraction of AGN than field galaxies at similar redshifts. This lower AGN fraction is inconsistent with the expectation that the higher gas fractions at high redshift, combined with the high galaxy densities and modest relative velocities in protoclusters, should produce higher AGN fractions.

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arXiv2018

Molecular gas reservoirs in cluster galaxies at z=1.46

We present molecular gas reservoirs of eighteen galaxies associated with the XMMXCS J2215.9-1738 cluster at z=1.46. From Band 7 and Band 3 data of the Atacama Large Millimeter/submillimeter Array (ALMA), we detect dust continuum emission at 870 um and CO J=2-1 emission line from 8 and 17 member galaxies respectively within a cluster-centric radius of $R_{200}$. The molecular gas masses derived from the CO and/or dust continuum luminosities show that the fraction of molecular gas mass and the depletion time scale for the cluster galaxies are larger than expected from the scaling relations of molecular gas on stellar mass and offset from the main sequence of star-forming galaxies in general fields. The galaxies closer to the cluster center in terms of both projected position and accretion phase seem to show a larger deviation from the scaling relations. We speculate that the environment of galaxy cluster helps feed the gas through inflow to the member galaxies and also reduce the efficiency of star formation. The stacked Band 3 spectrum of 12 quiescent galaxies with stellar mass $\sim10^{11}$ M$_\odot$ within 0.5$R_{200}$ shows no detection of CO emission line, giving the upper limit of molecular gas mass and molecular gas fraction to be $<10^{10}$ M$_\odot$ and $<10$%, respectively. Therefore, the massive galaxies in the cluster core quench the star formation activity while consuming most of the gas reservoirs.

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arXiv2018

Ionized and molecular gas kinematics in a z=1.4 star-forming galaxy

We present deep observations of a $z=1.4$ massive, star-forming galaxy in molecular and ionized gas at comparable spatial resolution (CO 3-2, NOEMA; H$α$, LBT). The kinematic tracers agree well, indicating that both gas phases are subject to the same gravitational potential and physical processes affecting the gas dynamics. We combine the one-dimensional velocity and velocity dispersion profiles in CO and H$α$ to forward-model the galaxy in a Bayesian framework, combining a thick exponential disk, a bulge, and a dark matter halo. We determine the dynamical support due to baryons and dark matter, and find a dark matter fraction within one effective radius of $f_{\rm DM}(\leq$$R_{e})=0.18^{+0.06}_{-0.04}$. Our result strengthens the evidence for strong baryon-dominance on galactic scales of massive $z\sim1-3$ star-forming galaxies recently found based on ionized gas kinematics alone.

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