Molecular Gas and Star Formation Properties in Early Stage Mergers: SMA CO(2-1) Observations of the LIRGs NGC 3110 and NGC 232

Espada, Daniel; Martín, S.; Verley, S.; Pettitt, Alex R.; Matsushita, Satoki; Argudo-Fernández, M.; Randriamanakoto, Zara; Hsieh, Po‐Jang; Saito, Toshiki; Miura, Rie; Kawana, Yuka; Sabater, J.; Verdes–Montenegro, L.; Ho, Paul T. P.; Kawabe, Ryohei; Iono, Daisuke

doi:10.3847/1538-4357/aae07e

Cited by 22 publications

(42 citation statements)

References 138 publications

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“…If we assume our α CO,uplim estimates, we obtain τ dep median values of ∼0.5 and 0.6 Gyr for HATLAS114625 and HAT-LAS121446, respectively. In this case, both starbursts mainly present τ dep values within 0.2−2.2 Gyr, a range similar to that reported for the two local LIRGs (0.2−1.6 Gyr; Espada et al 2018). In any case, the depletion times estimated for both galaxies are lower than the τ dep median values reported for local SFGs with similar Σ H 2 and f H 2 values (Leroy et al 2013).…”

Section: The Star-formation Activity Traced At ∼Kpc-scalessupporting

confidence: 86%

“…We compared our Σ SFR −Σ H 2 estimates with ∼kpc-scale local galaxy measurements and the ∼sub-kpc data from local ULIRGs. Briefly, the ∼kpc-scale data are represented by the median trend reported from the HERA CO-Line Extragalactic Survey (HERACLES, Leroy et al 2008) for normal star-forming systems and measurements from two LIRGs (NGC 3110 and NGC 232; Espada et al 2018). The local ULIRG data correspond to the CO(1-0)-based ∼350−650 pc-scale estimates presented in Wilson et al (2019).…”

Section: The Star-formation Activity Traced At ∼Kpc-scalesmentioning

confidence: 99%

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Vales

Molina

Ibar

Godoy

et al. 2020

A&A

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Context. Spatially resolved observations of the ionized and molecular gas are critical for understanding the physical processes that govern the interstellar medium (ISM) in galaxies. The observation of starburst systems is also important as they present extreme gas conditions that may help to test different ISM models. However, matched resolution imaging at ∼kpc scales for both ISM gas phases are usually scarce, and the ISM properties of starbursts still remain poorly understood. Aims. We aim to study the morpho-kinematic properties of the ionized and molecular gas in three dusty starburst galaxies at z = 0.12−0.17 to explore the relation between molecular ISM gas phase dynamics and the star-formation activity. Methods. We employ two-dimensional dynamical modelling to analyse Atacama Large Millimeter/submillimiter Array CO(1–0) and seeing-limited Spectrograph for INtegral Field Observations in the Near Infrared Paschen-α (Paα) observations, tracing the molecular and ionized gas morpho-kinematics at ∼kpc-scales. We use a dynamical mass model, which accounts for beam-smearing effects, to constrain the CO-to-H2 conversion factor and estimate the molecular gas mass content. Results. One starburst galaxy shows irregular morphology, which may indicate a major merger, while the other two systems show disc-like morpho-kinematics. The two disc-like starbursts show molecular gas velocity dispersion values comparable with those seen in local luminous and ultra luminous infrared galaxies but in an ISM with molecular gas fraction and surface density values in the range of the estimates reported for local star-forming galaxies. We find that these molecular gas velocity dispersion values can be explained by assuming vertical pressure equilibrium. We also find that the star-formation activity, traced by the Paα emission line, is well correlated with the molecular gas content, suggesting an enhanced star-formation efficiency and depletion times of the order of ∼0.1−1 Gyr. We find that the star-formation rate surface density (ΣSFR) correlates with the ISM pressure set by self-gravity (Pgrav) following a power law with an exponent close to 0.8. Conclusions. In dusty disc-like starburst galaxies, our data support the scenario in which the molecular gas velocity dispersion values are driven by the ISM pressure set by self-gravity and are responsible for maintaining the vertical pressure balance. The correlation between ΣSFR and Pgrav suggests that, in these dusty starbursts galaxies, the star-formation activity arises as a consequence of the ISM pressure balance.

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Section: The Star-formation Activity Traced At ∼Kpc-scalessupporting

confidence: 86%

Section: The Star-formation Activity Traced At ∼Kpc-scalesmentioning

confidence: 99%

Vales

Molina

Ibar

Godoy

et al. 2020

A&A

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“…Briefly, the 'z ∼ 0 spirals' sample is composed by high spatial resolution (∼ 0.2 − 1 kpc) observations of small galactic regions taken from Kennicutt et al (2007); Blanc et al (2009);Rahman et al (2011Rahman et al ( , 2012. The 'z ∼ 0 LIRGs' sample consist in observations of the NGC3110 and NGC232 galaxies observed at ∼ 1 kpc scale (Espada et al 2018). Both starburst systems have SFR∼ 20 M yr −1 , i.e.…”

Section: The Kennicutt-schmidt Law At ∼Kpc-scalesmentioning

confidence: 99%

“…comparable with the value reported for SHiZELS-19 (SFR=23 M yr −1 ). NGC3110 is a barred Sb galaxy interacting with a minor companion (mass ratio ∼14:1), whilst NGC232 corresponds to a barred Sa galaxy which presents a bright compact nuclear region (see Espada et al 2018, for more details). We also compare with the median trend observed for a sub-sample of 30 local galaxies taken from the HERA CO Line Extragalactic Survey (HERACLES; Leroy et al 2013).…”

Section: The Kennicutt-schmidt Law At ∼Kpc-scalesmentioning

confidence: 99%

“…The 'z ∼ 0 Spirals' sample consist in observations of local disks taken fromKennicutt et al (2007);Blanc et al (2009);Rahman et al (2011Rahman et al ( , 2012 at spatial resolutions between ∼ 0.2 − 1 kpc. The 'z ∼ 0 LIRGs' values consist in ∼ 1 kpc scale observations of two galaxies(Espada et al 2018). The green circles show the median trend observed in the HERACLES survey) at ∼kpc-scales and the black line represents the best-fit for those median values.…”

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confidence: 99%

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The kiloparsec-scale gas kinematics in two star-forming galaxies at z ∼ 1.47 seen with ALMA and VLT-SINFONI

Molina

Ibar

Smail

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present Atacama Large Millimeter/submillimeter Array (ALMA) CO(J = 2−1) observations of two main-sequence star-forming galaxies at z ∼ 1.47 taken from the High-Z Emission Line Survey (HiZELS). These two systems have been previously reported to be molecular gas rich f H 2 ≡ M H 2 /(M H 2 + M ) ∼ 0.8. We carried out a follow-up study to resolve, at ∼kpc-scales, the CO emission. These new observations are combined with our earlier ALMA observations (sensitive to diffuse CO emission) and compared with our previous Hα-based study at matched spatial resolution. One target is marginally resolved in CO(2-1), showing complex dynamics with respect to the ionised gas traced by Hα. While the other source is spatially resolved, enabling a detailed exploration of its internal dynamical properties. In this system, both gaseous phases show similar spatial extension, rotation velocities and velocity dispersions (V rot ∼ σ v ∼ 100 km s −1 ) suggesting a rotational velocity to velocity dispersion ratio consistent with unity. By comparing the ionized and molecular gas tracers through the use of a two-dimensional kinematic model, we estimate a median depletion time τ dep = 2.3 ± 1.2 Gyr for the galaxy as a whole. This value is in agreement with the average τ dep value observed in local star-forming galaxies at similar spatial scales. Using a thick-disk dynamical modelling, we derive a dynamical mass M dyn = (1.59 ± 0.19) × 10 11 M within ≈ 6 kpc. This suggests a dark matter fraction ( f DM ≡ M DM /M dyn ) of 0.59 ± 0.10, in agreement with the average f DM value derived from stacked rotation curve analysis of galaxies at similar redshift range.

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The SUNBIRD Survey: Insights into small-scale star formation mechanisms through near-infrared study of Young Massive Clusters

2021

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We draw the K-band luminosity functions (CLFs) of young massive clusters (YMCs) hosted by 34 SUNBIRD targets to evaluate the impact of the host galaxy environment on their YMC properties. The depth and high resolution of the NIR images (PSF ∼ 0.1”) allow us to test whether CLF power-law slopes (α) of high star-forming galaxies are similar to those of gas-poor low star formation rate (SFR) galaxies. We found that α ranges between 1.53 and 2.41 with a median value of 1.87 ± 0.23. We also performed correlation searches between α and the host global properties and noticed that α decreases with an increasing SFR and SFR density. On sub-galactic scales, CLF slopes of cluster-rich galaxies differ by ∼0.5. Our NIR CLF analyses suggest that the extreme environment of high SFR galaxies such as the SUNBIRD sample is likely to affect the formation mechanisms of YMCs and hence to govern the ongoing small-scale SF processes of the host galaxy.

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Molecular Gas and Star Formation Properties in Early Stage Mergers: SMA CO(2-1) Observations of the LIRGs NGC 3110 and NGC 232

Cited by 22 publications

References 138 publications

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The kiloparsec-scale gas kinematics in two star-forming galaxies at z ∼ 1.47 seen with ALMA and VLT-SINFONI

The SUNBIRD Survey: Insights into small-scale star formation mechanisms through near-infrared study of Young Massive Clusters

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