Braving the Storm: Quantifying Disk-wide Ionized Outflows in the Large Magellanic Cloud with ULLYSES
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| Autores principales: | , , , , , , , , , , , , , |
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| Formato: | Preprint |
| Publicado: |
2024
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| _version_ | 1866929447839465472 |
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| author | Zheng, Yong Tchernyshyov, Kirill Olsen, Knut Choi, Yumi Bustard, Chad Roman-Duval, Julia Zhu, Robert Di Teodoro, Enrico M. Werk, Jessica Putman, Mary McLeod, Anna F. Faerman, Yakov Simons, Raymond C. Peek, Joshua |
| author_facet | Zheng, Yong Tchernyshyov, Kirill Olsen, Knut Choi, Yumi Bustard, Chad Roman-Duval, Julia Zhu, Robert Di Teodoro, Enrico M. Werk, Jessica Putman, Mary McLeod, Anna F. Faerman, Yakov Simons, Raymond C. Peek, Joshua |
| contents | The Large Magellanic Cloud (LMC) is home to many HII regions, which may lead to significant outflows. We examine the LMC's multiphase gas ($T\sim10^{4-5}$ K) in HI, SII, SiIV, and CIV using 110 stellar sight lines from the HST's Ultraviolet Legacy Library of Young Stars as Essential Standards (ULLYSES) program. We develop a continuum fitting algorithm based on the concept of Gaussian Process regression and identify reliable LMC interstellar absorption over $v_{\rm helio}=175-375$ km s$^{-1}$. Our analyses show disk-wide ionized outflows in SiIV and CIV across the LMC with bulk velocities of $|v_{\rm out, bulk}|\sim20-60$ km s$^{-1}$, which indicates that most of the outflowing mass is gravitationally bound. The outflows' column densities correlate with the LMC's star formation rate surface densities ($Σ_{\rm SFR}$), and the outflows with higher $Σ_{\rm SFR}$ tend to be more ionized. Considering outflows from both sides of the LMC as traced by CIV, we conservatively estimate a total outflow rate of $\dot{M}_{\rm out}\gtrsim 0.03~M_\odot {\rm yr}^{-1}$ and a mass loading factor of $η\gtrsim 0.15$. We compare the LMC's outflows with those detected in starburst galaxies and simulation predictions, and find a universal scaling relation of $|v_{\rm out, bulk}|\propto Σ_{\rm SFR}^{0.23}$ over a wide range of star-forming conditions ($Σ_{\rm SFR}\sim10^{-4.5}-10^{2}~M_\odot {\rm yr}^{-1} {\rm kpc}^{-2}$). Lastly, we find that the outflows are co-rotating with the LMC's young stellar disk and the velocity field does not seem to be significantly impacted by external forces; we thus speculate on the existence of a bow shock leading the LMC, which may have shielded the outflows from ram pressure as the LMC orbits the Milky Way. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2402_04313 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Braving the Storm: Quantifying Disk-wide Ionized Outflows in the Large Magellanic Cloud with ULLYSES Zheng, Yong Tchernyshyov, Kirill Olsen, Knut Choi, Yumi Bustard, Chad Roman-Duval, Julia Zhu, Robert Di Teodoro, Enrico M. Werk, Jessica Putman, Mary McLeod, Anna F. Faerman, Yakov Simons, Raymond C. Peek, Joshua Astrophysics of Galaxies The Large Magellanic Cloud (LMC) is home to many HII regions, which may lead to significant outflows. We examine the LMC's multiphase gas ($T\sim10^{4-5}$ K) in HI, SII, SiIV, and CIV using 110 stellar sight lines from the HST's Ultraviolet Legacy Library of Young Stars as Essential Standards (ULLYSES) program. We develop a continuum fitting algorithm based on the concept of Gaussian Process regression and identify reliable LMC interstellar absorption over $v_{\rm helio}=175-375$ km s$^{-1}$. Our analyses show disk-wide ionized outflows in SiIV and CIV across the LMC with bulk velocities of $|v_{\rm out, bulk}|\sim20-60$ km s$^{-1}$, which indicates that most of the outflowing mass is gravitationally bound. The outflows' column densities correlate with the LMC's star formation rate surface densities ($Σ_{\rm SFR}$), and the outflows with higher $Σ_{\rm SFR}$ tend to be more ionized. Considering outflows from both sides of the LMC as traced by CIV, we conservatively estimate a total outflow rate of $\dot{M}_{\rm out}\gtrsim 0.03~M_\odot {\rm yr}^{-1}$ and a mass loading factor of $η\gtrsim 0.15$. We compare the LMC's outflows with those detected in starburst galaxies and simulation predictions, and find a universal scaling relation of $|v_{\rm out, bulk}|\propto Σ_{\rm SFR}^{0.23}$ over a wide range of star-forming conditions ($Σ_{\rm SFR}\sim10^{-4.5}-10^{2}~M_\odot {\rm yr}^{-1} {\rm kpc}^{-2}$). Lastly, we find that the outflows are co-rotating with the LMC's young stellar disk and the velocity field does not seem to be significantly impacted by external forces; we thus speculate on the existence of a bow shock leading the LMC, which may have shielded the outflows from ram pressure as the LMC orbits the Milky Way. |
| title | Braving the Storm: Quantifying Disk-wide Ionized Outflows in the Large Magellanic Cloud with ULLYSES |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2402.04313 |