Gas Dynamics and Star Formation in NGC 6822

Park, Hye-Jin; Oh, Se–Heon; Wang, Jing; Zheng, Yun; Zhang, Hong Xin; Blok, W. J. G. de

doi:10.3847/1538-3881/ac7c1b

Cited by 4 publications

(1 citation statement)

References 98 publications

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“…Moreover, de Blok & Walter (2000) and Park et al (2022) presented an H I distribution of NGC 6822. A possible tidal arm with a kinematical timescale of about 100 Myr is found in NGC 6822.…”

Section: Ngc 6822mentioning

confidence: 94%

The Star Formation History in Local Group Galaxies. I. Ten Dwarf Galaxies

Ren 任,

Jiang 姜,

Wang 王

et al. 2024

ApJ

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The star formation histories (SFHs) of galaxies provide valuable insights into galaxy evolution and stellar physics. Understanding the SFHs enables the study of chemical enrichment of galaxies, star formation triggered by interactions, and the behavior of various stellar populations. This work investigates the SFHs of ten dwarf galaxies in the Local Group (LG), which spans a wide range of types, masses, luminosities, and metallicities. The analysis is based on our new sample of the member stars in the LG after removing foreground dwarf stars by using information from the near-infrared color–color diagram and Gaia astrometry. The sample includes the most complete and pure red supergiants and asymptotic giant branch stars to gain valuable insights into the recent SFHs of the galaxies. A fitting method based on the color–magnitude diagram (CMD) is introduced to measure the SFH. The Padova isochrones are used to generate initial model CMDs, accounting for photometric errors and completeness through star-field simulations to match the completeness and error distributions of the observed CMDs. Subsequently, the SFHs, distance modulus, and metallicity of the ten dwarf galaxies are determined by fitting the CMDs. The results indicate that the star formation rates of dwarf irregulars show a gradual increase, while those of dwarf ellipticals exhibit a gradual decrease from the past to the present. Furthermore, this work shows that the star formation activity in dwarf ellipticals persisted up to 30 Myr ago. A significant increasing feature in the SFH of NGC 6822 reveals star formation activity triggered by an interaction event.

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“…Moreover, de Blok & Walter (2000) and Park et al (2022) presented an H I distribution of NGC 6822. A possible tidal arm with a kinematical timescale of about 100 Myr is found in NGC 6822.…”

Section: Ngc 6822mentioning

confidence: 94%

The Star Formation History in Local Group Galaxies. I. Ten Dwarf Galaxies

Ren 任,

Jiang 姜,

Wang 王

et al. 2024

ApJ

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WALLABY Pilot Survey: H i gas kinematics of galaxy pairs in cluster environment

Kim

Wang

et al. 2022

Monthly Notices of the Royal Astronomical Society

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We examine the H i gas kinematics of galaxy pairs in two clusters and a group using Australian Square Kilometre Array Pathfinder (ASKAP) WALLABY pilot survey observations. We compare the H i properties of galaxy pair candidates in the Hydra I and Norma clusters, and the NGC 4636 group, with those of non-paired control galaxies selected in the same fields. We perform H i profile decomposition of the sample galaxies using a tool, baygaud which allows us to de-blend a line-of-sight velocity profile with an optimal number of Gaussian components. We construct H i super-profiles of the sample galaxies via stacking of their line profiles after aligning the central velocities. We fit a double Gaussian model to the super-profiles and classify them as kinematically narrow and broad components with respect to their velocity dispersions. Additionally, we investigate the gravitational instability of H i gas disks of the sample galaxies using Toomre Q parameters and H i morphological disturbances. We investigate the effect of the cluster environment on the H i properties of galaxy pairs by dividing the cluster environment into three subcluster regions (i.e., outskirts, infalling and central regions). We find that the denser cluster environment (i.e., infalling and central regions) is likely to impact the H i gas properties of galaxies in a way of decreasing the amplitude of the kinematically narrow H i gas ($M_{\rm {narrow}}^{\rm {HI}}$/$M_{\rm {total}}^{\rm {HI}}$), and increasing the Toomre Q values of the infalling and central galaxies. This tendency is likely to be more enhanced for galaxy pairs in the cluster environment.

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The Interstellar Medium in Dwarf Irregular Galaxies

Hunter,

Elmegreen,

Madden

2024

Annual Review of Astronomy and Astrophysics

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Dwarf irregular (dIrrs) galaxies are among the most common type of galaxy in the Universe. They typically have gas-rich, low surface-brightness, metal-poor, and relatively thick disks. Here, we summarize the current state of our knowledge of the interstellar medium (ISM), including atomic, molecular, and ionized gas, along with their dust properties and metals. We also discuss star-formation feedback, gas accretion, and mergers with other dwarfs that connect the ISM to the circumgalactic and intergalactic media. We highlight one of the most persistent mysteries: the nature of pervasive gas that is yet undetected as either molecular or cold hydrogen, the “dark gas.” Some highlights include the following: ▪ Significant quantities of Hi are in far-outer gas disks. ▪ Cold Hi in dIrrs would be molecular in the Milky Way, making the chemical properties of star-forming clouds significantly different. ▪ Stellar feedback has a much larger impact in dIrrs than in spiral galaxies. ▪ The escape fraction of ionizing photons is significant, making dIrrs a plausible source for reionization in the early Universe. ▪ Observations suggest a significantly higher abundance of hydrogen (H2 or cold Hi) associated with CO in star-forming regions than that traced by the CO alone.

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Gas Dynamics and Star Formation in NGC 6822

Cited by 4 publications

References 98 publications

The Star Formation History in Local Group Galaxies. I. Ten Dwarf Galaxies

The Star Formation History in Local Group Galaxies. I. Ten Dwarf Galaxies

WALLABY Pilot Survey: H i gas kinematics of galaxy pairs in cluster environment

The Interstellar Medium in Dwarf Irregular Galaxies

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