HVCS Related to the Magellanic System

Putman, Mary E.

doi:10.1007/1-4020-2579-3_5

Cited by 3 publications

(3 citation statements)

References 75 publications

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“…Near the disc some of the HVCs are likely to arise through a galactic fountain, where numerous supernova launch gas from the disc of the Galaxy (Bregman 1980), however, this process is likely to produce small, intermediate velocity clouds over HVCs (Ford, Lockman, & McClure-Griffiths 2010). Many HVCs that lie within 50 kpc of the Milky Way likely had their origin in the Magellanic Stream and thus arose from the LMC and SMC (Putman 2004). Extragalactic HVCs are seen at a wide range of projected distances, often exceeding 150 kpc from the nearest galaxy, are likely to be clumps of pristine gas infalling for the first time and possess a phase-space distribution that is incompatible with the expected dark matter substructure (Chynoweth, Langston & Holley-Bockelmann 2011).…”

Section: Introductionmentioning

confidence: 99%

The Smith Cloud and its dark matter halo: survival of a Galactic disc passage

Nichols¹,

Mirabal²,

Agertz³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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The current velocity of the Smith Cloud indicates that it has undergone at least one passage of the Galactic disc. Using hydrodynamic simulations we examine the present day structure of the Smith Cloud. We find that a dark matter supported cloud is able to reproduce the observed present day neutral hydrogen mass, column density distribution and morphology. In this case the dark matter halo becomes elongated, owing to the tidal interaction with the Galactic disc. Clouds in models neglecting dark matter confinement are destroyed upon disc passage, unless the initial cloud mass is well in excess of what is observed today. We then determine integrated flux upper limits to the gamma-ray emission around such a hypothesised dark matter core in the Smith Cloud. No statistically significant core or extended gamma-ray emission are detected down to a 95% confidence level upper limit of 1.4 ×10 −10 ph cm −2 s −1 in the 1-300 GeV energy range. For the derived distance of 12.4 kpc, the Fermi upper limits set the first tentative constraints on the dark matter cross sections annihilating into τ + τ − and bb for a high-velocity cloud.

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Section: Introductionmentioning

confidence: 99%

The Smith Cloud and its dark matter halo: survival of a Galactic disc passage

Nichols¹,

Mirabal²,

Agertz³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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“…In addition, our high-velocity O VI clouds can only be produced via the galactic fountain, i.e., triggered by stellar feedback (e.g., Shapiro & Field 1976;Bregman 1980;Fraternali & Binney 2006). If other mechanisms such as accretion from the IGM (e.g., Kereš & Hernquist 2009;Fraternali et al 2015) and materials stripped or ejected from satellites (e.g., Putman 2004;Herenz et al 2013) are also responsible for the formation of high-velocity O VI, our simulation (Table 3) may underproduce high-velocity O VI content and distort its spatial distribution.…”

Section: Isolated Galaxy Simulationmentioning

confidence: 97%

“…In addition, the covering fraction of high-velocity O VI (60%; e.g., Sembach et al 2003;Fox et al 2006) is found to be higher than that of neutral and moderately ionized HVCs (∼20%-40% for H I, C IV, and Si IV; e.g., Lockman 2002;Herenz et al 2013), indicating a spatially more extended distribution for highly ionized HVCs. Despite the multiple origins proposed for HVCs, for example, the Galactic fountain (e.g., Shapiro & Field 1976;Bregman 1980;Fraternali & Binney 2006), materials stripped or ejected from satellite galaxies (e.g., Putman 2004;Herenz et al 2013), and accretion from the intergalactic medium (IGM; e.g., Kereš & Hernquist 2009;Fraternali et al 2015), the spatial distribution and kinematics of high-velocity O VI are probably dominantly governed by the fountain model, which proposes that gas circulation in the halo is powered by stellar feedback, e.g., stellar winds and supernova (SN) explosions. Such a scenario is also supported by recently observed rainlike inflows and collimated outflows (e.g., Lehner et al 2022;Marasco et al 2022).…”

Section: Introductionmentioning

confidence: 99%

Low- and High-velocity O vi in Milky Way-like Galaxies: The Role of Stellar Feedback

Zhang 张,

Li 李

et al. 2024

ApJ

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Milky Way-type galaxies are surrounded by a warm-hot gaseous halo containing a considerable amount of baryons and metals. The kinematics and spatial distribution of highly ionized ion species such as O vi can be significantly affected by supernova (SN) explosions and early (pre-SN) stellar feedback (e.g., stellar winds, radiation pressure). Here we investigate effects of stellar feedback on O vi absorptions in Milky Way−like galaxies by analyzing the suites of high-resolution hydrodynamical simulations under the framework of SMUGGLE, a physically motivated subgrid interstellar medium and stellar feedback model for the moving-mesh code Arepo. We find that the fiducial run with the full suite of stellar feedback and moderate star formation activities can reasonably reproduce Galactic O vi absorptions observed by space telescopes such as the Far-Ultraviolet Spectroscopic Explorer, including the scale height of low-velocity (∣v LSR∣ < 100 km s−1) O vi, the column density–line width relation for high-velocity (100 km s−1 ≤ ∣v LSR∣ < 400 km s−1) O vi, and the cumulative O vi column densities. In contrast, model variations with more intense star formation activities deviate from observations further. Additionally, we find that the run considering only SN feedback is in broad agreement with the observations, whereas in runs without SN feedback this agreement is absent, which indicates a dominant role of SN feedback in heating and accelerating interstellar O vi. This is consistent with the current picture that interstellar O vi is predominantly produced by collisional ionization where mechanical feedback can play a central role. In contrast, photoionization is negligible for O vi production owing to the lack of high-energy (≳114 eV) photons required.

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Gaseous Galaxy Halos

Putman

Peek

Joung

2012

Annu. Rev. Astron. Astrophys.

461

479

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Galactic halo gas traces inflowing star formation fuel and feedback from a galaxy's disk and is therefore crucial to our understanding of galaxy evolution. In this review, we summarize the multi-wavelength observational properties and origin models of Galactic and low redshift spiral galaxy halo gas. Galactic halos contain multiphase gas flows that are dominated in mass by the ionized component and extend to large radii. The densest, coldest halo gas observed in neutral hydrogen (HI) is generally closest to the disk (< 20 kpc), and absorption line results indicate warm and warm-hot diffuse halo gas is present throughout a galaxy's halo. The hot halo gas detected is not a significant fraction of a galaxy's baryons. The disk-halo interface is where the multiphase flows are integrated into the star forming disk, and there is evidence for both feedback and fueling at this interface from the temperature and kinematic gradient of the gas and HI structures. The origin and fate of halo gas is considered in the context of cosmological and idealized local simulations. Accretion along cosmic filaments occurs in both a hot (> 10 5.5 K) and cold mode in simulations, with the compressed material close to the disk the coldest and densest, in agreement with observations. There is evidence in halo gas observations for radiative and mechanical feedback mechanisms, including escaping photons from the disk, supernova-driven winds, and a galactic fountain. Satellite accretion also leaves behind abundant halo gas. This satellite gas interacts with the existing halo medium, and much of this gas will become part of the diffuse halo before it can reach the disk. The accretion rate from cold and warm halo gas is generally below a galaxy disk's star formation rate, but gas at the disk-halo interface and stellar feedback may be important additional fuel sources.

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HVCS Related to the Magellanic System

Cited by 3 publications

References 75 publications

The Smith Cloud and its dark matter halo: survival of a Galactic disc passage

The Smith Cloud and its dark matter halo: survival of a Galactic disc passage

Low- and High-velocity O vi in Milky Way-like Galaxies: The Role of Stellar Feedback

Gaseous Galaxy Halos

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