arXiv subjects

Jingyao Zhu

Publications and source records attributed to Jingyao Zhu.

8 recordsLinked to original sources

arXiv2026

The Halo Gas of Local Spiral Galaxies and the Link to Gaseous Satellites

Gaseous satellites orbiting massive host galaxies experience gas stripping and may contribute additional gas to the hosts' circumgalactic medium (CGM). We identify a sample of 21 local spiral galaxies ($<$15 Mpc) and characterize their gaseous satellite populations from existing HI surveys to investigate the connection between host galaxy CGM and satellite gas content. Most of our spiral hosts have $\leq3$ gaseous satellites in their halos with $M_{\rm HI}\gtrsim10^{7}~M_\odot$. Using 26 HST/COS QSO sightlines at impact parameters of 0.1--0.9 $R_{\rm 200c}$, we find that the CGM of $z\sim0$ spiral galaxies show large intrinsic scatters ($\sim1-2$ dex) in ion column densities and harbor a total cool gas mass of $2.5^{+7.5}_{\rm -1.9}\times10^9~(0.3Z_\odot/Z')~M_\odot$, largely consistent with their $z\sim0.2$ counterparts (e.g., COS-Halos). Splitting our sample by the presence of gaseous satellites, we find that galaxy hosts with gaseous satellites have higher detection rates (up to 50\%) in metal ion absorbers, including OI, AlII, CII, SiII, SiIII, and SiIV, possibly because their CGM is more metal enriched or has more ionized gas in the cool phase. However, the CGM column densities show no significant correlation with either the number of gaseous satellites or their total HI masses, suggesting that the contribution from the gaseous satellites to the host CGM is likely small compared to the intrinsic scatters in the CGM profiles, and the profile trends are mainly influenced by sightlines' proximity to the hosts. The CGM detection rate becomes elevated when a sightline is within half the virial radius of a massive gaseous satellite (LMC-like or higher mass), likely due to stripped debris.

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arXiv2026

Up, Up, and Away? Quantifying ISM Fallback using Ram Pressure Stripping Simulations

The evolution of the cold interstellar medium (ISM) in satellite galaxies orbiting through massive hosts is an important factor in how they evolve while experiencing ram pressure stripping (RPS), as cold molecular gas clouds are the most difficult ISM component to fully strip and serve as the sites of star formation. We investigate ISM evolution using a suite of hydrodynamical wind tunnel simulations with an intermediate mass ($M_* = 10^{9.7}$ M$_\odot$) galaxy orbiting in a Coma cluster-like environment, varying the disk-wind angle. Even if the ultimate fate of a ram pressure stripped galaxy is complete gas removal, we find that cold gas evolves through cycles of outflow and inflow (fallback). We show that fallback can be identified at a wide range of wind angles, but is elevated for angles closer to edge-on and occurs predominantly in a specific quadrant (trailing side, rotating into the wind). Most inflow occurs in gas that never leaves an ``inner tail" region that extends to $\sim20$ kpc. We discuss possible reasons for when and why fallback occurs using simple idealized simulations. For a highly inclined disk, offset rotational motion is a major driver of fallback, while disk shadowing and cloud growth can act at all wind angles. Lastly, we discuss the relative importance of each mechanism at different stages of a galaxy's evolution under ram pressure, and compare our findings with instances of ISM fallback detected in observed RPS galaxies.

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arXiv2026

Too Big to Quench? I. Constraining ISM Stripping of Dwarf Satellites in Milky Way-like Halos

Galaxy environment plays a crucial role in quenching star formation in dwarf galaxies. In Milky Way (MW)-like environments, dwarf satellite quenching is primarily driven by ram pressure stripping (RPS), the direct removal of satellite gas by the host halo gas. Using a suite of 20-pc resolution hydrodynamical wind tunnel simulations, we constrain the satellite mass scale at which the stripping of a dwarf galaxy's interstellar medium (ISM) becomes inefficient in MW-like halos. The simulations include radiative cooling in a multiphase satellite ISM, star formation, and stellar feedback, and vary both satellite masses ($M_{\star}=10^{6.2}, 10^{6.8}, 10^{7.2}\ M_{\odot}$) and host halo gas densities along a first-infall and post-pericentric orbit. We find that the degree of ISM stripping in our dwarf galaxies is consistent with the analytical prediction by McCarthy et al. (2008). Star formation is rapidly quenched when RPS is effective, but can be mildly enhanced or temporarily quenched and subsequently reignited when RPS is incomplete. ISM stripping is efficient for satellites with $M_{\star} \lesssim 10^{7}\ M_{\odot}$ (or $M_{200} \lesssim 10^{10}\ M_{\odot}$) but highly inefficient above this scale. This transitional mass ($M_{\star} \approx 10^{7}\ M_{\odot}$) is 0.5-1 dex lower than that found in observations and cosmological simulations, suggesting that additional mechanisms are needed to quench more massive satellites, such as tidal stripping of the satellite dark matter or RPS from a clumpy gaseous halo.

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arXiv2025

Baryonic Masses and Properties of Gaseous Satellite Galaxies

We present a sample of 127 gas-bearing dwarf galaxies around 56 late-type host galaxies within 30 Mpc using 21-cm HI data from the WALLABY, MHONGOOSE, and ALFALFA surveys. We characterize the environment of each dwarf galaxy based on its host galaxy halo and derive optical properties using the DESI Legacy Surveys for 110. The gaseous satellites span $\log (M_{\rm HI}/M_{\odot}) = 5.8-9.7$ and $\log (M_{\star}/M_{\odot}) = 5.6-10.0$, with a median velocity line-width of $W_{50}=40$ km/s, comparable to the Local Group gaseous dwarf galaxies. We assess the HI mass sensitivity of the data by injecting model dwarf galaxies and find $M_{\rm HI,lim} \approx 10^{6.7} M_{\odot}$ for WALLABY and $M_{\rm HI,lim} \approx 10^{5.4} M_{\odot}$ for MHONGOOSE at 10 Mpc. Our sample has lower average atomic gas fractions ($M_{\rm HI}/M_{\star}$) than previous gaseous dwarf samples in field and satellite environments, although this offset partly reflects differences in HI sensitivity. The abundance of gaseous satellites per host is low and increases with host mass: $0-2$ for dwarf centrals and $0-5$ for Milky Way-mass spiral hosts. These numbers are consistent with the Milky Way, M31, and star-forming satellite abundances from recent deep optical surveys. The inferred quenched fractions and gas-depleted satellites indicate that environmental quenching is effective in Milky Way-mass hosts, likely driven by gas stripping processes.

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arXiv2025

Caught in the Cosmic Web: Evidence for Ram-Pressure Stripping of a Low-Mass Galaxy by the Cosmic Web

We present interferometric radio observations of the neutral atomic gas in AGC 727130, a low-mass, gas-rich, field galaxy lacking significant star-formation. The atomic gas in AGC 727130 displays a pronounced asymmetry, extending well beyond the stellar disk in one direction while remaining relatively undisturbed in the other. Despite proximity to a pair of interacting dwarfs, tidal analysis suggests these neighboring galaxies are not responsible for this pronounced asymmetry. Instead, using a topological cosmic web filament finder on spectroscopic catalogue data, we find AGC 727130 lies at the intersection of several large-scale cosmic web filaments, environments predicted to host diffuse, shock-heated gas. We propose that an interaction with this ambient medium is stripping gas from the galaxy via cosmic web ram-pressure stripping. This mechanism, supported by recent simulations, may quench low-mass galaxies outside of massive halos, and must be accounted for when comparing observed numbers of dwarf galaxies to theoretical predictions.

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arXiv2024

It's a Breeze: The Circumgalactic Medium of a Dwarf Galaxy is Easy to Strip

The circumgalactic medium (CGM) of star-forming dwarf galaxies plays a key role in regulating the galactic baryonic cycle. We investigate how susceptible the CGM of dwarf satellite galaxies is to ram pressure stripping (RPS) in Milky Way-like environments. In a suite of hydrodynamical wind tunnel simulations, we model an intermediate-mass dwarf satellite galaxy ($M_{*} = 10^{7.2}~M_{\odot}$) with a multiphase interstellar medium (ISM; $M_{\rm ISM} = 10^{7.9}~M_{\odot}$) and CGM ($M_{\rm CGM,vir} = 10^{8.5}~M_{\odot}$) along two first-infall orbits to more than 500 Myr past pericenter of a Milky Way-like host. The spatial resolution is $\sim$79 pc in the star-forming ISM and $316-632$ pc in the CGM. Our simulations show that the dwarf satellite CGM removal is fast and effective: more than $95\%$ of the CGM mass is ram-pressure-stripped within a few hundred Myrs, even under a weak ram pressure orbit where the ISM stripping is negligible. The conditions for CGM survival are consistent with the analytical halo gas stripping predictions in McCarthy et al. (2008). We also find that including the satellite CGM does not effectively shield its galaxy, and therefore the ISM stripping rate is unaffected. Our results imply that a dwarf galaxy CGM is unlikely to be detected in satellite galaxies; and that the star formation of gaseous dwarf satellites is likely devoid of replenishment from a CGM.

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arXiv2023

When and how does ram pressure stripping in low-mass satellite galaxies enhance star formation

We investigate how a satellite's star formation rate (SFR) and surviving gas respond to ram pressure stripping in various environments. Using a suite of high-resolution "wind-tunnel" simulations with radiative cooling, star formation, and supernovae feedback, we model the first infall orbit of a low-mass disk galaxy ($M_{*} = 10^{9.7} M_{\odot}$) in different host halos, ranging from Milky Way-like to cluster hosts. When the ram pressure is moderate, we find that the stripping satellite shows an enhanced SFR relative to the isolated control case, despite gas loss due to stripping. The SFR enhancement is caused, not directly by compression, but by ram pressure-driven mass flows, which can increase the dense gas fraction in the central disk regions. The spatially-resolved star formation main sequence and Kennicutt-Schmidt relations in our simulations are consistent with recent findings of the VERTICO and GASP surveys. Our results predict the environmental signals of RPS in future multiwavelength, high-angular resolution observations: the star formation and gas surface densities will be centralized, and symmetrically enhanced within the stripping radius.

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arXiv2023

Census of Gaseous Satellites around Local Spiral Galaxies

We present a search for gas-containing dwarf galaxies as satellite systems around nearby spiral galaxies using 21 cm neutral hydrogen (HI) data from the Arecibo Legacy Fast ALFA (ALFALFA) Survey. We have identified 15 spiral `primary' galaxies in a local volume of 10 Mpc with a range of total masses, and have found 19 gas-containing dwarf satellite candidates within the primaries' virial volumes ($R_{200}$) and 46 candidates within $2R_{200}$. Our sensitivity using ALFALFA data converts to $M_{\rm HI} \approx 7.4 \times 10^{6}$ $M_{\odot}$ at 10 Mpc, which includes 13 of the 26 gaseous dwarf galaxies in the Local Group, and the HI properties of our sample are overall similar to these 13. We found $0-3$ gaseous satellites per host galaxy within $R_{200}$ and $0-5$ within $2R_{200}$, which agrees with the low numbers present for the Milky Way and M31. There is also agreement with the star-forming satellite numbers per host in the deep optical surveys SAGA and ELVES, and the Auriga cosmological simulations. When scaled to $R_{200}$, the optical surveys do not show a trend of increasing quenched fraction with host mass; there is a slight increase in the total number of gaseous satellites with host mass for our sample. The low numbers of gaseous/star-forming satellites around spiral hosts are consistent with the idea that a universal and effective satellite quenching mechanism, such as ram pressure stripping by the host halo, is likely at play.

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