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The Diffuse Ionized Gas of the Large Magellanic Cloud

Authors :
Smart, B. M.
Haffner, L. M.
Barger, K. A.
Ciampa, D. A.
Hill, A. S.
Krishnarao, D.
Madsen, G. J.
Source :
ApJ 948 118 (2023)
Publication Year :
2023

Abstract

The Large Magellanic Cloud (LMC) has an extensive H$_{\alpha}$ emission halo that traces an extended, warm ionized component of its interstellar medium. Using the Wisconsin H$_{\alpha}$ Mapper (WHAM) telescope, we present the first kinematic \ha\ survey of an extensive region around the LMC, from $l,b = (264\deg .5,\,-45\deg .5)$ to $(295\deg .5,\,-19\deg .5)$, covering $+150\leq v_{lsr} \leq +390~ km s^{-1}$. We find that ionized hydrogen exists throughout the galaxy and extends several degrees beyond detected neutral hydrogen emission $(\log{\left(N_{\rm H_{~I}/\rm cm^{-2}}\right)\approx18.3})$ as traced by 21-cm in current surveys. Using the column density structure of the neutral gas and stellar line-of-sight depths as a guide, we estimate the upper limit mass of the ionized component of the LMC to be roughly $M_\mathrm{ionized}\approx (0.6-1.8)\times 10^{9}\,\mathrm{M}_{sun}$, which is comparable to the total neutral atomic gas mass in the same region ($M_\mathrm{neutral}\approx0.75-0.85\times10^{9}\,\mathrm{M}_{sun}$). Considering only the atomic phases, we find $M_\mathrm{ionized}/M_\mathrm{ionized+neutral}$, to be 46\%--68\% throughout the LMC and its extended halo. Additionally, we find an ionized gas cloud that extends off of the LMC at $l,b \approx (285\deg, -28\deg)$ into a region previously identified as the Leading Arm complex. This gas is moving at a similar line-of-sight velocity as the LMC and has $M_\mathrm{ionized}/M_\mathrm{ionized+neutral} =$ 13\%--51\%. This study, combined with previous studies of the SMC and extended structures of the Magellanic Clouds, continues to suggest that warm, ionized gas is as massive and dynamically-important as the neutral gas in the Magellanic System.$<br />Comment: 20 pages, 12 figures, 4 tables

Details

Database :
arXiv
Journal :
ApJ 948 118 (2023)
Publication Type :
Report
Accession number :
edsarx.2305.09829
Document Type :
Working Paper
Full Text :
https://doi.org/10.3847/1538-4357/acc06e