Spatially resolved kinematics in the central 1 kpc of a compact star-forming galaxy at z=2.3 from ALMA CO observations

Abstract

We present high spatial resolution (FWHM$\sim$0.14'') observations of the CO($8-7$) line in GDS-14876, a compact star-forming galaxy at $z=2.3$ with total stellar mass of $\log (M_{\star }/M_{\odot })=10.9$. The spatially resolved velocity map of the inner $r\lesssim 1$~kpc reveals a continous velocity gradient consistent with the kinematics of a rotating disk with $v_{\mathrm{rot}}(r=1\mathrm{kpc})=163\pm 5$ km s${}^{-1}$ and $v_{\mathrm{rot}}/\sigma \sim 2.5$. The gas-to-stellar ratios estimated from CO($8-7$) and the dust continuum emission span a broad range, $f_{\mathrm{gas}}^{\mathrm{CO}}=M_{\mathrm{gas}}/M_{\star }=13-45\%$ and $f_{\mathrm{gas}}^{\mathrm{cont}}=50-67\%$, but are nonetheless consistent given the uncertainties in the conversion factors. The dynamical modeling yields a dynamical mass of$\log (M_{\mathrm{dyn}}/M_{\odot })=10.58_{-0.2}^{+0.5}$ which is lower, but still consistent with the baryonic mass, $\log$(M${}_{\mathrm{bar}}$= M${}_{\star }$ + M${}_{\mathrm{gas}}^{\mathrm{CO}}$/M${}_{\odot }$)$=11.0$, if the smallest CO-based gas fraction is assumed. Despite a low, overall gas fraction, the small physical extent of the dense, star-forming gas probed by CO($8-7$), $\sim 3\times$ smaller than the stellar size, implies a strong concentration that increases the gas fraction up to $f_{\mathrm{gas}}^{\mathrm{CO},1\mathrm{kpc}}\sim 85\%$ in the central 1 kpc. Such a gas-rich center, coupled with a high star-formation rate, SFR$\sim$ 500 M${}_{\odot }$ yr${}^{-1}$, suggests that GDS-14876 is quickly assembling a dense stellar component (bulge) in a strong nuclear starburst. Assuming its gas reservoir is depleted without replenishment, GDS-14876 will quickly ($t_{\mathrm{depl}}\sim 27$ Myr) become a compact quiescent galaxy that could retain some fraction of the observed rotational support.

arXiv commentAccepted for Publication in ApJL. Kinematic maps are shown in Figures 2 and 4

References in corpus (50)

• emcee: The MCMC Hammer
• Stellar population synthesis at the resolution of 2003
• Galactic Stellar and Substellar Initial Mass Function
• The Dust Content and Opacity of Actively Star-Forming Galaxies
• CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey
• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• Detailed Decomposition of Galaxy Images. II. Beyond Axisymmetric Models
• GOODS-Herschel: an infrared main sequence for star-forming galaxies
• Interpreting the Cosmic Infrared Background: Constraints on the Evolution of the Dust Enshrouded Star Formation Rate
• An ultra-deep near-infrared spectrum of a compact quiescent galaxy at z=2.2
• The Infrared Spectral Energy Distribution of Normal Star-Forming Galaxies: Calibration at Far-Infrared and Submillimeter Wavelengths
• Passively Evolving Early-type Galaxies at 1.4<z<2.5 in the Hubble Ultra Deep Field
• Constraining the Low-Mass Slope of the Star Formation Sequence at 0.5<z<2.5
• Galaxy Structure and Mode of Star Formation in the SFR-Mass Plane from z ~ 2.5 to z ~ 0.1
• Submillimeter Galaxies at z~2: Evidence for Major Mergers & Constraints on Lifetimes, IMF and CO-H2 Conversion Factor
• Combined CO & Dust Scaling Relations of Depletion Time and Molecular Gas Fractions with Cosmic Time, Specific Star Formation Rate and Stellar Mass
• Determining Star Formation Rates for Infrared Galaxies
• The CO-to-H2 Conversion Factor and Dust-to-Gas Ratio on Kiloparsec Scales in Nearby Galaxies
• The KMOS^3D Survey: design, first results, and the evolution of galaxy kinematics from 0.7<z<2.7
• Compaction and Quenching of High-z Galaxies in Cosmological Simulations: Blue and Red Nuggets
• CANDELS Multi-wavelength Catalogs: Source Detection and Photometry in the GOODS-South Field
• ISM masses and the star formation law at Z = 1 to 6 // ALMA observations of dust continuum in 145 galaxies in the COSMOS survey field
• Strong size evolution of the most massive galaxies since z~2
• Smooth(er) Stellar Mass Maps in CANDELS: Constraints on the Longevity of Clumps in High-redshift Star-forming Galaxies
• Forming Compact Massive Galaxies
• CO excitation of normal star forming galaxies out to z=1.5 as regulated by the properties of their interstellar medium
• The Formation of Massive, Compact Galaxies at z=2 in the Illustris Simulation
• A universal structural and star-forming relation since $z\sim 3$: connecting compact star-forming and quiescent galaxies
• Where stars form: inside-out growth and coherent star formation from HST Halpha maps of 2676 galaxies across the main sequence at z~1
• The Origin of Cosmic Dust
• Stellar Kinematics of z~2 Galaxies and the Inside-Out Growth of Quiescent Galaxies
• CANDELS+3D-HST: compact SFGs at z~2-3, the progenitors of the first quiescent galaxies
• A Redshift Survey of Herschel Far-Infrared Selected Starbursts and Implications for Obscured Star Formation
• Sub-kpc ALMA imaging of compact star-forming galaxies at z~2.5: revealing the formation of dense galactic cores in the progenitors of compact quiescent galaxies
• VLA and ALMA Imaging of Intense, Galaxy-Wide Star Formation in z ~ 2 Galaxies
• L'CO/LFIR Relations with CO Rotational Ladders of Galaxies Across the Herschel SPIRE Archive
• KMOS^3D: Dynamical constraints on the mass budget in early star-forming disks
• A massive, dead disk galaxy in the early Universe
• The VLA Survey of the Chandra Deep Field South: I. Overview of the Radio Data
• The MOSDEF Survey: Dynamical and Baryonic Masses and Kinematic Structures of Star-Forming Galaxies at $1.4\le z\le 2.6$
• The Warm Molecular Gas Around the Cloverleaf Quasar
• Keck-I MOSFIRE spectroscopy of compact star-forming galaxies at z$\gtrsim$2: High velocity dispersions in progenitors of compact quiescent galaxies
• MOSFIRE Absorption Line Spectroscopy of z > 2 Quiescent Galaxies: Probing a Period of Rapid Size Growth
• ALMA reveals starburst-like interstellar medium conditions in a compact star-forming galaxy at z ~ 2 using [CI] and CO
• Discovery of a Strongly Lensed Massive Quiescent Galaxy at z=2.636: Spatially Resolved Spectroscopy and Indications of Rotation
• Rotating starburst cores in massive galaxies at z=2.5
• Exploring the evolutionary paths of the most massive galaxies since z~2
• 13CO and C18O emission from a dense gas disk at z=2.3: abundance variations, cosmic rays and the initial conditions for star formation
• Low Gas Fractions Connect Compact Star-Forming Galaxies to their z ~ 2 Quiescent Descendants
• SXDF-ALMA 1.5 arcmin^2 deep survey. A compact dusty star-forming galaxy at z=2.5

Cited by in corpus (39)

• A Unified Model for Galactic Discs: Star Formation, Turbulence Driving, and Mass Transport
• MOSFIRE Spectroscopy of Quiescent Galaxies at 1.5 < z < 2.5. II - Star Formation Histories and Galaxy Quenching
• COSMOS-DASH: The Evolution of the Galaxy Size-Mass Relation Since z~3 from new Wide Field WFC3 Imaging Combined with CANDELS/3DHST
• Fast and slow paths to quiescence: ages and sizes of 400 quiescent galaxies from the LEGA-C survey
• Resolving Quiescent Galaxies at $z\gtrsim 2$: II. Direct Measures of Rotational Support
• Starburst to quiescent from HST/ALMA: Stars and dust unveil minor mergers in submillimeter galaxies at $z\sim 4.5$
• The Dramatic Size and Kinematic Evolution of Massive Early-Type Galaxies
• Dissecting the size-mass and ${\Sigma }_1$-mass relations at 1.0 < z < 2.5: galaxy mass profiles and color gradients as a function of spectral shape
• Wet Compaction to a Blue Nugget: a Critical Phase in Galaxy Evolution
• CO emission in distant galaxies on and above the main sequence
• Resolving Quiescent Galaxies at $z\gtrsim 2$: I. Search for Gravitationally Lensed Sources and Characterization of their Structure, Stellar Populations, and Line Emission
• ALMA view of a massive spheroid progenitor: a compact rotating core of molecular gas in an AGN host at z=2.226
• Systematic difference between ionized and molecular gas velocity dispersion in $z\sim 1-2$ disks and local analogues
• GOODS-ALMA: 1.1 mm galaxy survey - I. Source catalogue and optically dark galaxies
• GOODS-ALMA: The slow downfall of star-formation in $z$ = 2-3 massive galaxies
• Origin of Star-Forming Rings around Massive Centres in Massive Galaxies at $z<4$
• New Analytic Solutions for Galaxy Evolution: Gas, Stars, Metals and Dust in local Early-Type Galaxies and in their high-z Starforming Progenitors
• The rocky road to quiescence: compaction and quenching of quasar host galaxies at z~2
• An ALMA survey of the SCUBA-2 Cosmology Legacy Survey UKIDSS/UDS field: Identifying candidate z~4.5 [CII] emitters
• The ALPINE-ALMA [C II] Survey: [C II]158micron Emission Line Luminosity Functions at $z\sim 4-6$
• Inverse stellar population age gradients of post-starburst galaxies at z=0.8 with LEGA-C
• Evidence for Inside-Out Galaxy Growth and Quenching of a z~2 Compact Galaxy from High-Resolution Molecular Gas Imaging
• Compaction-Driven Black Hole Growth
• Towards sub-kpc scale kinematics of molecular and ionized gas of star-forming galaxies at $z\sim 1$
• Towards an Understanding of the Massive Red Spiral Galaxy Formation
• Compact Star-Forming Galaxies as Old Starbursts Becoming Quiescent
• A ~600 pc view of the strongly-lensed, massive main sequence galaxy J0901: a baryon-dominated, thick turbulent rotating disk with a clumpy cold gas ring at z = 2.259
• Quenching by gas compression and consumption: A case study of a massive radio galaxy at z = 2.57
• Importance of Mock Observations in Validating Galaxy Properties for Cosmological Simulations
• Neutral carbon and highly excited CO in a massive star-forming main sequence galaxy at z=2.2
• Concurrent starbursts in molecular gas disks within a pair of colliding galaxies at z = 1.52
• A multi-wavelength study of a massive, active galaxy at $z\sim 2$: coupling the kinematics of the ionized and molecular gas
• A Radio-to-millimeter Census of Star-forming Galaxies in Protocluster 4C~23.56 at z = 2.5 : Global and local gas kinematics
• Starbursts with suppressed velocity dispersion revealed in a forming cluster at z=2.51
• Structures, stellar population properties, AGN fractions, and environments of massive compact galaxies at $1<z<2$ in 3D--{\it HST}/CANDELS
• Environment from cross-correlations: connecting hot gas and the quenching of galaxies
• The Origin of Massive Compact Galaxies: Lessons from IllustrisTNG
• Anomalously Narrow Linewidths of Compact Massive Star-Forming Galaxies at z~2.3: A Possible Inclination Bias in the Size-Mass Plane
• Extremely Low Molecular Gas Content in the Vicinity of a Red Nugget Galaxy at $z=1.91$