Spatially Resolved Dust, Gas, and Star Formation in the Dwarf Magellanic Irregular NGC 4449<sup>*</sup>

Calzetti, Daniela; Wilson, Grant; Draine, B. T.; Roussel, H.; Johnson, K. E.; Wall, W. F.; Grasha, Kathryn; Battisti, Andrew; Andrews, Jennifer E.; Kirkpatrick, Allison; González, Daniel Rosa; Vega, O.; Puschnig, Johannes; Yun, Min S.; Östlin, Göran; Evans, A. S.; Tang, Yuping; Lowenthal, James D.; Sánchez-Argüelles, David

doi:10.3847/1538-4357/aaa1e2

Cited by 20 publications

(31 citation statements)

References 115 publications

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“…AD12 (their Appendix F) found that even when the global photometry has PACS/MIPS ≈ 1, the PACS and MIPS images (with PACS convolved to the MIPS PSF) can have local surface brightnesses discrepant by factors as large as 1.5-2.0. Similar discrepancies were found when comparing PACS and MIPS imaging of M31 (Draine et al 2014) and NGC 4449 (Calzetti et al 2018). Figure 2 illustrates that even after summing over the full galaxy mask, PACS70 and MIPS70 often disagree by more than a factor 1.2, and sometimes up to a factor 1.4.…”

Section: Why Both Mips and Pacs Are Neededsupporting

confidence: 60%

Modeling Dust and Starlight in Galaxies Observed by Spitzer and Herschel: The KINGFISH Sample

Aniano

Draine

Hunt

et al. 2020

ApJ

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Dust and starlight are modeled for the KINGFISH project galaxies. With data from 3.6µm to 500µm, models are strongly constrained. For each pixel in each galaxy we estimate (1) dust surface density; (2) q PAH , the dust mass fraction in PAHs; (3) distribution of starlight intensities heating the dust; (4) luminosity emitted by the dust; and (5) dust luminosity from regions with high starlight intensity. The models successfully reproduce both global and resolved spectral energy distributions. We provide well-resolved maps for the dust properties. As in previous studies, we find q PAH to be an increasing function of metallicity, above a threshold Z/Z ≈ 0.15. Dust masses are obtained by summing the dust mass over the map pixels; these "resolved" dust masses are consistent with the masses inferred from model fits to the global photometry. The global dust-to-gas ratios obtained from

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Section: Why Both Mips and Pacs Are Neededsupporting

confidence: 60%

Modeling Dust and Starlight in Galaxies Observed by Spitzer and Herschel: The KINGFISH Sample

Aniano

Draine

Hunt

et al. 2020

ApJ

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“…The post-Planck correction factor described in Aniano et al (2020) has been applied to the value of M dust . The high value of U min , U min 12, is not uncommon in regions of strong star formation (e.g., Calzetti et al 2018). Using the formula of Draine et al (2014), the characteristic dust temperature in the Central Region of NGC 3351 is T d ∼27 K, consistent with its starburst nature, and in agreement with the temperature determination of Nersesian et al (2020).…”

Section: Dust Emission Propertiessupporting

confidence: 74%

“…The emission in each band will also be proportional to the total dust mass, M dust . and Aniano et al (2020) established that the derived dust emission parameters are not sensitive to the choice of U max , which we fix at a value of 10 5 , borrowing from the study of Calzetti et al (2018). Thus, for each given extinction curve, there are a total of four parameters for the models: q P AH , U min , γ, and M dust .…”

Section: Dust Emission Modelsmentioning

confidence: 99%

Revisiting Attenuation Curves: the Case of NGC 3351

Calzetti,

Battisti,

Shivaei

et al. 2021

Preprint

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Multi-wavelength images from the farUV (∼0.15 µm) to the sub-millimeter of the central region of the galaxy NGC 3351 are analyzed to constrain its stellar populations and dust attenuation. Despite hosting a ∼1 kpc circumnuclear starburst ring, NGC 3351 deviates from the IRX-β relation, the relation between the infrared-to-UV luminosity ratio and the UV continuum slope β that other starburst galaxies follow. To understand the reason for the deviation, we leverage the high angular resolution of archival nearUV-to-nearIR HST images to divide the ring into ∼60-180 pc size regions and model each individually. We find that the UV slope of the combined intrinsic (dust-free) stellar populations in the central region is redder than what is expected for a young model population. This is due to the region's complex star formation history, which boosts the nearUV emission relative to the farUV. The resulting net attenuation curve has a UV slope that lies between those of the starburst attenuation curve (Calzetti et al. 2000) and the Small Magellanic Cloud extinction curve; the total-to-selective attenuation value, R (V)=4.93, is larger than both. As found for other star-forming galaxies, the stellar continuum of NGC 3351 is less attenuated than the ionized gas, with E(B-V) star =0.40 E(B-V) gas . The combination of the 'red' intrinsic stellar population and the new attenuation curve fully accounts for the location of the central region of NGC 3351 on the IRX-β diagram. Thus, the observed characteristics result from the complex mixture of stellar populations and dust column densities in the circumnuclear region. Despite being a sample of one, these findings highlight the difficulty of defining attenuation curves of general applicability outside the regime of centrally-concentrated starbursts.

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“…Evans et al 2009Evans et al , 2014Heiderman et al 2010;Gutermuth et al 2011), in starburst galaxies (e.g. Genzel et al 2010Genzel et al , 2015, in the dwarf magellanic irregular galaxy NGC 4449 (Calzetti et al 2018), and also in galactic centres (e.g. Leroy et al 2013).…”

Section: Introductionmentioning

confidence: 99%

The Lyman Alpha Reference Sample

Puschnig

Hayes

Östlin

et al. 2020

A&A

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Context. Lyman-α (Lyα) is the brightest emission line in star-forming galaxies. However, its interpretation in terms of physical properties is hampered by the resonant nature of Lyα photons. In order to remedy this complicated situation, the Lyman Alpha Reference Sample (LARS) was defined, enabling the study of Lyα production and escape mechanisms in 14 local star-forming galaxies. Aims. With this paper, we complement our efforts and study the global dust and (molecular) gas content as well as the properties of gas associated with photon-dominated regions. We aim to characterize the interstellar medium of LARS galaxies, allowing us to relate these newly derived properties to quantities relevant for Lyα escape. Methods. We observed LARS galaxies with Herschel, SOFIA, the IRAM 30m telescope, and APEX, targeting far-infrared (FIR) continuum and emission lines of [C II]158 μm, [O I]63 μm, [O III]88 μm, and low-J CO lines. Using Bayesian methods we derived dust model parameters and estimated the total gas masses for all LARS galaxies, taking into account a metallicity-dependent gas-to-dust ratio. Star formation rates were estimated from FIR, [C II]158 μm, and [O I]63 μm luminosities. Results. LARS covers a wide dynamic range in the derived properties, with FIR-based star formation rates from ∼0.5−100 M⊙ yr−1, gas fractions between ∼15−80%, and gas depletion times ranging from a few hundred megayears up to more than ten gigayears. The distribution of LARS galaxies in the Σgas versus ΣSFR (Kennicutt–Schmidt plane) is thus quite heterogeneous. However, we find that LARS galaxies with the longest gas depletion times, that is, relatively high gas surface densities (Σgas) and low star formation rate densities (ΣSFR), have by far the highest Lyα escape fraction. A strong approximately linear relation is found between the Lyα escape fraction and the total gas (HI+H2) depletion time. We argue that the Lyα escape in those galaxies is driven by turbulence in the star-forming gas that shifts the Lyα photons out of resonance close to the places where they originate. We further report on an extreme [C II]158 μm excess in LARS 5, corresponding to ∼14 ± 3% of the FIR luminosity, which probably is the most extreme [C II]-to-FIR ratio observed in a galaxy (without active nucleus) to date.

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Spatially Resolved Dust, Gas, and Star Formation in the Dwarf Magellanic Irregular NGC 4449^*

Cited by 20 publications

References 115 publications

Modeling Dust and Starlight in Galaxies Observed by Spitzer and Herschel: The KINGFISH Sample

Modeling Dust and Starlight in Galaxies Observed by Spitzer and Herschel: The KINGFISH Sample

Revisiting Attenuation Curves: the Case of NGC 3351

The Lyman Alpha Reference Sample

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Spatially Resolved Dust, Gas, and Star Formation in the Dwarf Magellanic Irregular NGC 4449*

Cited by 20 publications

References 115 publications

Modeling Dust and Starlight in Galaxies Observed by Spitzer and Herschel: The KINGFISH Sample

Modeling Dust and Starlight in Galaxies Observed by Spitzer and Herschel: The KINGFISH Sample

Revisiting Attenuation Curves: the Case of NGC 3351

The Lyman Alpha Reference Sample

Contact Info

Product

Resources

About

Spatially Resolved Dust, Gas, and Star Formation in the Dwarf Magellanic Irregular NGC 4449^*