The SAMI galaxy survey: gas velocity dispersions in low-z star-forming galaxies and the drivers of turbulence

ABSTRACT We infer the intrinsic ionized gas kinematics for 383 star-forming galaxies across a range of integrated star formation rates (SFR ∈ [10−3, 102] M⊙ yr−1) at z ≲ 0.1 using a consistent 3D forward-modelling technique. The total sample is a combination of galaxies from the Sydney-AAO Multiobject Integral field Spectrograph (SAMI) Galaxy survey and DYnamics of Newly Assembled Massive Objects survey. For typical low-z galaxies taken from the SAMI Galaxy Survey, we find the vertical velocity dispersion (σv,z) to be positively correlated with measures of SFR, stellar mass, H i gas mass, and rotational velocity. The greatest correlation is with SFR surface density (ΣSFR). Using the total sample, we find σv,z increases slowly as a function of integrated SFR in the range SFR ∈ [10−3, 1] M⊙ yr−1 from 17 ± 3 to 24 ± 5 km s−1 followed by a steeper increase up to σv,z ∼80 km s−1 for SFR ≳ 1 M⊙ yr−1. This is consistent with recent theoretical models that suggest a σv,z floor driven by star formation feedback processes with an upturn in σv,z at higher SFR driven by gravitational transport of gas through the disc.

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What drives the velocity dispersion of ionized gas in star-forming galaxies?

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1146 ◽

2019 ◽

Vol 486 (4) ◽

pp. 4463-4472 ◽

Cited By ~ 7

Author(s):

Xiaoling Yu ◽

Yong Shi ◽

Yanmei Chen ◽

David R Law ◽

Dmitry Bizyaev ◽

...

Keyword(s):

Star Formation ◽

Velocity Dispersion ◽

Gravitational Instability ◽

Theoretical Models ◽

Stellar Mass ◽

Ionized Gas ◽

Star Forming ◽

Energy Feedback ◽

Nearby Galaxies ◽

Stellar Masses

Abstract We analyse the intrinsic velocity dispersion properties of 648 star-forming galaxies observed by the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, to explore the relation of intrinsic gas velocity dispersions with star formation rates (SFRs), SFR surface densities ($\rm {\Sigma _{SFR}}$), stellar masses, and stellar mass surface densities ($\rm {\Sigma _{*}}$). By combining with high z galaxies, we found that there is a good correlation between the velocity dispersion and the SFR as well as $\rm {\Sigma _{SFR}}$. But the correlation between the velocity dispersion and the stellar mass as well as $\rm {\Sigma _{*}}$ is moderate. By comparing our results with predictions of theoretical models, we found that the energy feedback from star formation processes alone and the gravitational instability alone cannot fully explain simultaneously the observed velocity–dispersion/SFR and velocity–dispersion/$\rm {\Sigma _{SFR}}$ relationships.

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Gas dynamics and star formation in “isolated” and interacting galaxies using FP observations

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319008238 ◽

2019 ◽

Vol 14 (S353) ◽

pp. 264-265

Author(s):

Isaura Fuentes-Carrera ◽

Nelli Cárdenas-Martínez ◽

Martín Nava-Callejas ◽

Margarita Rosado

Keyword(s):

Star Formation ◽

Gas Dynamics ◽

Equal Mass ◽

Interacting Galaxies ◽

Ionized Gas ◽

Star Forming ◽

Gas Kinematics ◽

Fabry Perot ◽

Different Types

AbstractWe present scanning Fabry-Perot observations of different types of star-forming galaxies from apparently isolated LIRGs to equal mass interacting galaxies. We analyze the ionized gas kinematics, its relation with the morphology of each system and the location of SF regions for different systems.

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Towards sub-kpc scale kinematics of molecular and ionized gas of star-forming galaxies at z ∼ 1

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935896 ◽

2019 ◽

Vol 631 ◽

pp. A91 ◽

Cited By ~ 3

Author(s):

M. Girard ◽

M. Dessauges-Zavadsky ◽

F. Combes ◽

J. Chisholm ◽

V. Patrício ◽

...

Keyword(s):

Spatial Resolution ◽

Rotation Curve ◽

Velocity Dispersion ◽

Major Axis ◽

Stellar Disk ◽

Molecular Gas ◽

Ionized Gas ◽

Rotation Curves ◽

Star Forming ◽

Gas Kinematics

We compare the molecular and ionized gas kinematics of two strongly lensed galaxies at z ∼ 1 that lie on the main sequence at this redshift. The observations were made with ALMA and MUSE, respectively. We derive the CO and [O II] rotation curves and dispersion profiles of these two galaxies. We find a difference between the observed molecular and ionized gas rotation curves for one of the two galaxies, the Cosmic Snake, for which we obtain a spatial resolution of a few hundred parsec along the major axis. The rotation curve of the molecular gas is steeper than the rotation curve of the ionized gas. In the second galaxy, A521, the molecular and ionized gas rotation curves are consistent, but the spatial resolution is only a few kiloparsec on the major axis. Using simulations, we investigate the effect of the thickness of the gas disk and effective radius on the observed rotation curves and find that a more extended and thicker disk smoothens the curve. We also find that the presence of a strongly inclined (> 70°) thick disk (> 1 kpc) can smoothen the rotation curve because it degrades the spatial resolution along the line of sight. By building a model using a stellar disk and two gas disks, we reproduce the rotation curves of the Cosmic Snake with a molecular gas disk that is more massive and more radially and vertically concentrated than the ionized gas disk. Finally, we also obtain an intrinsic velocity dispersion in the Cosmic Snake of 18.5 ± 7 km s−1 and 19.5 ± 6 km s−1 for the molecular and ionized gas, respectively, which is consistent with a molecular disk with a smaller and thinner disk. For A521, the intrinsic velocity dispersion values are 11 ± 8 km s−1 and 54 ± 11 km s−1, with a higher value for the ionized gas. This could indicate that the ionized gas disk is thicker and more turbulent in this galaxy. These results highlight the diversity of the kinematics of galaxies at z ∼ 1 and the different spatial distribution of the molecular and ionized gas disks. It suggests the presence of thick ionized gas disks at this epoch and that the formation of the molecular gas is limited to the midplane and center of the galaxy in some objects.

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The MUSE Atlas of Discs (MAD): Ionized gas kinematic maps and an application to diffuse ionized gas

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3184 ◽

2019 ◽

Vol 491 (3) ◽

pp. 4089-4107 ◽

Cited By ~ 2

Author(s):

Mark den Brok ◽

C Marcella Carollo ◽

Santiago Erroz-Ferrer ◽

Martina Fagioli ◽

Jarle Brinchmann ◽

...

Keyword(s):

Velocity Dispersion ◽

Rotation Velocity ◽

Scale Height ◽

Molecular Gas ◽

Ionized Gas ◽

Nearby Star ◽

Stellar Disc ◽

Star Forming ◽

Gas Kinematics ◽

Diffuse Ionized Gas

ABSTRACT We have obtained data for 41 star forming galaxies in the MUSE Atlas of Discs (MAD) survey with VLT/MUSE. These data allow us, at high resolution of a few 100 pc, to extract ionized gas kinematics (V, σ) of the centres of nearby star forming galaxies spanning 3 dex in stellar mass. This paper outlines the methodology for measuring the ionized gas kinematics, which we will use in subsequent papers of this survey. We also show how the maps can be used to study the kinematics of diffuse ionized gas for galaxies of various inclinations and masses. Using two different methods to identify the diffuse ionized gas, we measure rotation velocities of this gas for a subsample of six galaxies. We find that the diffuse ionized gas rotates on average slower than the star forming gas with lags of 0–10 km s−1 while also having higher velocity dispersion. The magnitude of these lags is on average 5 km s−1 lower than observed velocity lags between ionized and molecular gas. Using Jeans models to interpret the lags in rotation velocity and the increase in velocity dispersion we show that most of the diffuse ionized gas kinematics are consistent with its emission originating from a somewhat thicker layer than the star forming gas, with a scale height that is lower than that of the stellar disc.

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SFR and Abundances of Nearby Galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316008358 ◽

2015 ◽

Vol 11 (S315) ◽

Author(s):

Marianne Takamiya ◽

Daniel Berke ◽

Forrest Bremer ◽

Casey Jones ◽

Guillaume Poquet

Keyword(s):

Star Formation ◽

Wavelength Range ◽

Star Forming ◽

Star Forming Regions ◽

Nearby Galaxies ◽

Integral Field Spectrograph ◽

Integral Field

AbstractWe present star formation rates and nebular abundances of 59 different star-forming regions in 16 nearby galaxies. The star-forming regions were selected to be bright in Hα and were observed with the SNIFS integral field spectrograph on the UH 2.2m telescope. The spectra span the wavelength range between 3200Å and 1μm. We find that the local star formation rates depend on the local abundances in that low SFRs show a dependence but high SFR appear insensitive to it.

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Ionized gas kinematics of massive elliptical galaxies in CALIFA and in cosmological zoom-in simulations

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936441 ◽

2020 ◽

Vol 635 ◽

pp. A41

Author(s):

Jan Florian ◽

Bodo Ziegler ◽

Michaela Hirschmann ◽

Polychronis Papaderos ◽

Ena Choi ◽

...

Keyword(s):

Radial Profile ◽

Major Axis ◽

Velocity Fields ◽

Host Galaxies ◽

Ionized Gas ◽

Massive Galaxies ◽

Gas Kinematics ◽

Major Merger ◽

Ordered Motion ◽

Integral Field

Context. Powerful active galactic nuclei (AGN) are supposed to play a key regulatory role on the evolution of their host galaxies by shaping the thermodynamic properties of their gas component. However, little is known as to the nature and the visibility timescale of the kinematical imprints of AGN-driven feedback. Gaining theoretical and observational insights into this subject is indispensable for a thorough understanding of the AGN-galaxy coevolution and could yield empirical diagnostics for the identification of galaxies that have experienced a major AGN episode in the past. Aims. We present an investigation of kinematical imprints of AGN feedback on the warm ionized gas medium (WIM) of massive early-type galaxies (ETGs). To this end, we take a two-fold approach that involves a comparative analysis of Hα velocity fields in 123 local ETGs from the CALIFA (Calar Alto Legacy Integral Field Area Survey) integral field spectroscopy survey with 20 simulated galaxies from high-resolution hydrodynamic cosmological SPHgal simulations. The latter were resimulated for two modeling setups, one with and another without AGN feedback. Methods. In order to quantify the effects of AGN feedback on gas kinematics, we measured three parameters that probe deviations from simple regular rotation by using the kinemetry package. These indicators trace the possible presence of distinct kinematic components in Fourier space (k3, 5/k1), variations in the radial profile of the kinematic major axis (σPA), and offsets between the stellar and gas velocity fields (Δϕ). These quantities were monitored in the simulations from a redshift 3 to 0.2 to assess the connection between black hole accretion history, stellar mass growth, and the kinematical perturbation of the WIM. Results. Observed local massive galaxies show a broad range of irregularities, indicating disturbed warm gas motions, which is irrespective of being classified via diagnostic lines as AGN or not. Simulations of massive galaxies with AGN feedback generally exhibit higher irregularity parameters than without AGN feedback, which is more consistent with observations. Besides AGN feedback, other processes like major merger events or infalling gas clouds can lead to elevated irregularity parameters, but they are typically of shorter duration. More specifically, k3, 5/k1 is most sensitive to AGN feedback, whereas Δϕ is most strongly affected by gas infall. Conclusions. We conclude that even if the general disturbance of the WIM velocity is not a unique indicator for AGN feedback, irregularity parameters that are high enough to be consistent with observations can only be reproduced in simulations with AGN feedback. Specifically, an elevated value for the deviation from simple ordered motion is a strong sign for previous events of AGN activity and feedback.

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From global to local scales in galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320001568 ◽

2020 ◽

Vol 15 (S359) ◽

pp. 391-395

Author(s):

Sebastian F. Sánchez ◽

Carlos Lopez Cobá

Keyword(s):

Star Formation ◽

Spatial Scales ◽

Bimodal Distribution ◽

Spectroscopic Properties ◽

Molecular Gas ◽

Ionized Gas ◽

Galaxy Surveys ◽

Quenching Process ◽

Formation Efficiency ◽

Integral Field

AbstractWe summarize here some of the results reviewed recently by Sanchez (2020) comprising the advances in the comprehension of galaxies in the nearby universe based on integral field spectroscopic galaxy surveys. In particular we explore the bimodal distribution of galaxies in terms of the properties of their ionized gas, showing the connection between the star-formation (quenching) process with the presence (absence) of molecular gas and the star-formation efficiency. We show two galaxy examples that illustrates the well known fact that ionization in galaxies (and the processes that produce it), does not happen monolitically at galactic scales. This highlight the importance to explore the spectroscopic properties of galaxies and the evolutionary processes unveiled by them at different spatial scales, from sub-kpc to galaxy wide.

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Constraining photoionization models with a reprojected optical diagnostic diagram

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3259 ◽

2020 ◽

Vol 499 (4) ◽

pp. 5749-5764 ◽

Cited By ~ 1

Author(s):

Xihan Ji ◽

Renbin Yan

Keyword(s):

Star Formation ◽

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Theoretical Models ◽

Line Ratio ◽

Star Forming ◽

Optical Diagnostic ◽

Diagnostic Diagram ◽

Upper Limits ◽

Nitrogen Abundance

ABSTRACT Optical diagnostic diagrams are powerful tools to separate different ionizing sources in galaxies. However, the model-constraining power of the most widely used diagrams is very limited and challenging to visualize. In addition, there have always been classification inconsistencies between diagrams based on different line ratios, and ambiguities between regions purely ionized by active galactic nuclei (AGNs) and composite regions. We present a simple reprojection of the 3D line ratio space composed of [N ii]λ6583/H α, [S ii]λλ6716, 6731/H α, and [O iii]λ5007/H β, which reveals its model-constraining power and removes the ambiguity for the true composite objects. It highlights the discrepancy between many theoretical models and the data loci. With this reprojection, we can put strong constraints on the photoionization models and the secondary nitrogen abundance prescription. We find that a single nitrogen prescription cannot fit both the star-forming locus and AGN locus simultaneously, with the latter requiring higher N/O ratios. The true composite regions stand separately from both models. We can compute the fractional AGN contributions for the composite regions, and define demarcations with specific upper limits on contamination from AGN or star formation. When the discrepancy about nitrogen prescriptions gets resolved in the future, it would also be possible to make robust metallicity measurements for composite regions and AGNs.

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Survival of molecular gas in a stellar feedback-driven outflow witnessed with the MUSE TIMER project and ALMA

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1844 ◽

2019 ◽

Vol 488 (3) ◽

pp. 3904-3928 ◽

Cited By ~ 6

Author(s):

Ryan Leaman ◽

Francesca Fragkoudi ◽

Miguel Querejeta ◽

Gigi Y C Leung ◽

Dimitri A Gadotti ◽

...

Keyword(s):

Magnetic Field ◽

Star Formation ◽

Mechanical Energy ◽

Molecular Gas ◽

Ionized Gas ◽

Star Forming ◽

Stellar Feedback ◽

Dominant Component ◽

The Galaxy ◽

Field Lines

ABSTRACT Stellar feedback plays a significant role in modulating star formation, redistributing metals, and shaping the baryonic and dark structure of galaxies – however, the efficiency of its energy deposition to the interstellar medium is challenging to constrain observationally. Here we leverage HST and ALMA imaging of a molecular gas and dust shell ($M_{\mathrm{ H}_2} \sim 2\times 10^{5}\, {\rm M}_{\odot }$) in an outflow from the nuclear star-forming ring of the galaxy NGC 3351, to serve as a boundary condition for a dynamical and energetic analysis of the outflowing ionized gas seen in our MUSE TIMER survey. We use starburst99 models and prescriptions for feedback from simulations to demonstrate that the observed star formation energetics can reproduce the ionized and molecular gas dynamics – provided a dominant component of the momentum injection comes from direct photon pressure from young stars, on top of supernovae, photoionization heating, and stellar winds. The mechanical energy budget from these sources is comparable to low luminosity active galactic neuclei, suggesting that stellar feedback can be a relevant driver of bulk gas motions in galaxy centres – although here ≲10−3 of the ionized gas mass is escaping the galaxy. We test several scenarios for the survival/formation of the cold gas in the outflow, including in situ condensation and cooling. Interestingly, the geometry of the molecular gas shell, observed magnetic field strengths and emission line diagnostics are consistent with a scenario where magnetic field lines aided survival of the dusty ISM as it was initially launched (with mass-loading factor ≲1) from the ring by stellar feedback. This system’s unique feedback-driven morphology can hopefully serve as a useful litmus test for feedback prescriptions in magnetohydrodynamical galaxy simulations.

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