scholarly journals Diffuse Ionized Gas in Simulations of Multiphase, Star-forming Galactic Disks

2020 ◽  
Vol 897 (2) ◽  
pp. 143 ◽  
Author(s):  
Erin Kado-Fong ◽  
Jeong-Gyu Kim ◽  
Eve C. Ostriker ◽  
Chang-Goo Kim
Keyword(s):  
Galactic Disks ◽  
Ionized Gas ◽  
Star Forming ◽  
Diffuse Ionized Gas

scholarly journals Estimating Dust Attenuation From Galactic Spectra. II. Stellar and Gas Attenuation in Star-forming and Diffuse Ionized Gas Regions in MaNGA

2021 ◽  
Vol 917 (2) ◽  
pp. 72
Author(s):  
Niu Li ◽  
Cheng Li ◽  
Houjun Mo ◽  
Shuang Zhou ◽  
Fu-heng Liang ◽  
...  
Keyword(s):  
Ionized Gas ◽  
Star Forming ◽  
Diffuse Ionized Gas ◽  
Dust Attenuation

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

2019 ◽  
Vol 491 (3) ◽  
pp. 4089-4107 ◽  
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.

scholarly journals Diffuse ionized gas and its effects on nebular metallicity estimates of star-forming galaxies

2019 ◽  
Vol 489 (4) ◽  
pp. 4721-4733 ◽  
Author(s):  
N Vale Asari ◽  
G S Couto ◽  
R Cid Fernandes ◽  
G Stasińska ◽  
A L de Amorim ◽  
...  
Keyword(s):  
Formation Rate ◽  
Sloan Digital Sky Survey ◽  
Emission Lines ◽  
Strong Line ◽  
Galactocentric Distance ◽  
Ionized Gas ◽  
Star Forming ◽  
Diffuse Ionized Gas ◽  
Stellar Masses ◽  
The Impact

ABSTRACT We investigate the impact of the diffuse ionized gas (DIG) on abundance determinations in star-forming (SF) galaxies. The DIG is characterized using the H α equivalent width (WH α). From a set of 1 409 SF galaxies from the Mapping Nearby Galaxies at APO (MaNGA) survey, we calculate the fractional contribution of the DIG to several emission lines using high-S/N data from SF spaxels (instead of using noisy emission-lines in DIG-dominated spaxels). Our method is applicable to spectra with observed WH α ≳ 10 Å (which are not dominated by DIG emission). Since the DIG contribution depends on galactocentric distance, we provide DIG-correction formulae for both entire galaxies and single aperture spectra. Applying those to a sample of $\, \gt 90\, 000$ SF galaxies from the Sloan Digital Sky Survey, we find the following. (1) The effect of the DIG on strong-line abundances depends on the index used. It is negligible for the ([O iii]/H β)/([N ii]/H α) index, but reaches ∼0.1 dex at the high-metallicity end for [N ii]/H α. (2) This result is based on the ∼kpc MaNGA resolution, so the real effect of the DIG is likely greater. (3) We revisit the mass–metallicity–star formation rate (SFR) relation by correcting for the DIG contribution in both abundances and SFR. The effect of DIG removal is more prominent at higher stellar masses. Using the [N ii]/Hα index, O/H increases with SFR at high stellar mass, contrary to previous claims.

scholarly journals GASP XXXV: Characteristics of the Diffuse Ionised Gas in Gas-stripped Galaxies

2021 ◽  
Vol 922 (2) ◽  
pp. 131
Author(s):  
Neven Tomičić ◽  
Benedetta Vulcani ◽  
Bianca M. Poggianti ◽  
Ariel Werle ◽  
Ancla Müller ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Spatial Scales ◽  
Dense Gas ◽  
Gas Stripping ◽  
Ionized Gas ◽  
Massive Galaxies ◽  
Star Forming ◽  
Diffuse Ionized Gas ◽  
The Difference ◽  
And Control

Abstract Diffuse ionized gas (DIG) is an important component of the interstellar medium that can provide insights into the different physical processes affecting the gas in galaxies. We utilize optical IFU observations of 71 gas-stripped and control galaxies from the Gas Stripping Phenomena in galaxies (GASP) survey, to analyze the gas properties of dense ionized gas and DIG, such as metallicity, ionization parameter log(q), and the difference between the measured log[O i]/Hα and the value predicted by star-forming models given the measured log[Oiii]/Hβ (Δ log[O i]/Hα). We compare these properties at different spatial scales, among galaxies at different gas-stripping stages, and between disks and tails of the stripped galaxies. The metallicity is similar between the dense gas and DIG at a given galactocentric radius. The log(q) is lower for DIG compared to dense gas. The median values of log(q) correlate best with stellar mass and the most massive galaxies show an increase in log(q) toward their galactic centers. The DIG clearly shows higher Δ log[O i]/Hα values compared to the dense gas, with much of the spaxels having LIER/LINER-like emission. The DIG regions in the tails of highly stripped galaxies show the highest Δ log[O i]/Hα, exhibit high values of log(q), and extend to large projected distances from star-forming areas (up to 10 kpc). We conclude that the DIG in the tails is at least partly ionized by a process other than star formation, probably by mixing, shocks, and accretion of inter-cluster and interstellar medium gas.

scholarly journals The importance of the diffuse ionized gas for interpreting galaxy spectra

2020 ◽  
Vol 15 (S359) ◽  
pp. 371-380
Author(s):  
Natalia Vale Asari ◽  
Grażyna Stasińska
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Active Galactic Nucleus ◽  
Early Type ◽  
Late Type ◽  
Chemical Abundances ◽  
Ionized Gas ◽  
Star Forming ◽  
Diffuse Ionized Gas ◽  
Emission Line Spectrum

AbstractDiffuse ionized gas (DIG) in galaxies can be found in early-type galaxies, in bulges of late-type galaxies, in the interarm regions of galaxy disks, and outside the plane of such disks. The emission-line spectrum of the DIG can be confused with that of a weakly active galactic nucleus. It can also bias the inference of chemical abundances and star formation rates in star forming galaxies. We discuss how one can detect and feasibly correct for the DIG contribution in galaxy spectra.

scholarly journals The diffuse ionized gas (DIG) in star-forming galaxies: the influence of aperture effects on local H ii regions

2021 ◽  
Vol 508 (2) ◽  
pp. 1582-1589
Author(s):  
F Mannucci ◽  
F Belfiore ◽  
M Curti ◽  
G Cresci ◽  
R Maiolino ◽  
...  
Keyword(s):  
Emission Line ◽  
Strong Line ◽  
H Ii Regions ◽  
Line Flux ◽  
Ionized Gas ◽  
Star Forming ◽  
Distant Galaxies ◽  
Diffuse Ionized Gas ◽  
Large Correction ◽  
Nearby Galaxies

ABSTRACT The diffuse ionized gas (DIG) contributes to the nebular emission of galaxies, resulting in emission line flux ratios that can be significantly different from those produced by H ii regions. Comparing the emission of [SII]λ6717,31 between pointed observations of H ii regions in nearby galaxies and integrated spectra of more distant galaxies, it has been recently claimed that the DIG can also deeply affect the emission of bright, star-forming galaxies, and that a large correction must be applied to observed line ratios to recover the genuine contribution from H ii regions. Here, we show instead that the e?ect of DIG on the integrated spectra of star-forming galaxies is lower than assumed in previous work. Here we show that, in contrast, aperture effects on the spectroscopy of nearby H ii regions are largely responsible for the observed difference: When spectra of local H ii regions are extracted using large enough apertures while still avoiding the DIG, the observed line ratios are the same as in more distant galaxies. This result is highly relevant for the use of strong-line methods to measure metallicity.

scholarly journals Diffuse Ionized Gas in Nearby Galaxies

1991 ◽  
Vol 144 ◽  
pp. 223-232
Author(s):  
R.A.M. Walterbos
Keyword(s):  
Interstellar Medium ◽  
Spectral Characteristics ◽  
High Ratio ◽  
Radio Continuum ◽  
Ionized Gas ◽  
Star Forming ◽  
Star Forming Regions ◽  
Diffuse Ionized Gas ◽  
External Galaxies ◽  
Nearby Galaxies

We discuss the distribution and spectral characteristics of diffuse ionized gas in nearby galaxies. The existence of this elusive component of the interstellar medium (ISM), also referred to as the Warm Ionized Medium, is by now well established from deep imaging and spectroscopic surveys in several emission lines in external galaxies. Diffuse ionized gas is characterized by a relatively high ratio of [SII] over Hα intensities, typically twice as high as for discrete HII regions. The diffuse gas has been mapped in both edge-on and more face-on galaxies providing information on the radial and vertical distribitions. Emission from diffuse ionized gas is strongest around star forming regions. The vertical distribution appears related to the radio continuum thick-disk emission. We also briefly discuss ionization mechanisms, and the connection between star formation characteristics and morphology of the interstellar medium.

scholarly journals 3D optical spectroscopic study of NGC 3344 with SITELLE: I. Identification and confirmation of supernova remnants

2019 ◽  
Vol 488 (1) ◽  
pp. 803-829 ◽  
Author(s):  
I Moumen ◽  
C Robert ◽  
D Devost ◽  
R P Martin ◽  
L Rousseau-Nepton ◽  
...  
Keyword(s):  
Supernova Remnants ◽  
Flux Ratio ◽  
Large Magellanic Cloud ◽  
Emission Lines ◽  
Ionization Mechanism ◽  
H Ii Regions ◽  
Nearby Galaxy ◽  
Galactocentric Distance ◽  
Ionized Gas ◽  
Diffuse Ionized Gas

ABSTRACT We present the first optical identification and confirmation of a sample of supernova remnants (SNRs) in the nearby galaxy NGC 3344. Using high spectral and spatial resolution data, obtained with the CFHT imaging Fourier transform spectrograph SITELLE, we identified about 2200 emission line regions, many of which are H ii regions, diffuse ionized gas regions, and also SNRs. Considering the stellar population and diffuse ionized gas background, which are quite important in NGC 3344, we have selected 129 SNR candidates based on four criteria for regions where the emission lines flux ratio [S ii]/H α ≥ 0.4. Emission lines of [O ii] λ3727, H β, [O iii] λλ4959,5007, H α, [N ii] λλ6548,6583, and [S ii] λλ6716,6731 have been measured to study the ionized gas properties of the SNR candidates. We adopted a self-consistent spectroscopic analysis, based on Sabbadin plots and Baldwin, Phillips & Terlevich diagrams, to confirm the shock-heated nature of the ionization mechanism in the candidates sample. With this analysis, we end up with 42 Confirmed SNRs, 45 Probable SNRs, and 42 Less likely SNRs. Using shock models, the confirmed SNRs seem to have a metallicity ranging between Large Magellanic Cloud and 2×solar. We looked for correlations between the size of the confirmed SNRs and their emission lines ratios, their galaxy environment, and their galactocentric distance: We see a trend for a metallicity gradient among the SNR population, along with some evolutionary effects.

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

2019 ◽  
Vol 488 (3) ◽  
pp. 3904-3928 ◽  
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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