Origin of the differences in rotational support among early-type galaxies: The case of galaxies outside clusters

Bílek, Michal; Duc, Pierre–Alain; Sola, Elisabeth

doi:10.1051/0004-6361/202244749

Cited by 6 publications

(6 citation statements)

References 219 publications

(304 reference statements)

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“…The histograms presented in the lower panels of for the two ETG categories provides p = 1.8 × 10 −15 , indicating a highly significant difference between the two distributions. This result aligns with those reported in previous studies (Bílek et al 2020(Bílek et al , 2023Yoon & Lim 2020).…”

Section: Resultssupporting

confidence: 94%

“…Since dynamical friction can make the infall orbit of satellite galaxies more radial, massive satellites are more likely to be accreted through radial orbits in the later stages of mergers (Amorisco 2017;Pop et al 2018). This could explain our observational result that shell-type tidal features are detected in slightly more massive ETGs, which is also found in the simulation of Pop et al (2018) and in the observation of Bílek et al (2023). We note that low-mass satellites require almost purely radial infall orbits at the initial accretion time in order to produce shells in the simulation of Pop et al (2018).…”

Section: Discussionsupporting

confidence: 75%

“…We classify the detected tidal features into three types, which are tails, streams, and shells. These are commonly used categories in previous studies (Duc et al 2015;Mancillas et al 2019;Bílek et al 2020Bílek et al , 2023Sola et al 2022). Tidal tails are thick, radially elongated structures that are visibly connected to the host galaxy.…”

Section: Detection and Classification Of Tidal Featuresmentioning

confidence: 99%

“…Tidal features are stellar debris generated by galaxy mergers (Toomre & Toomre 1972;Quinn 1984;Barnes 1988;Hernquist & Spergel 1992;Feldmann et al 2008), which are generally fainter than the main bodies of galaxies, necessitating deep images for their detection and examination. Hence, tidal features such as tidal tails, streams, and shells serve as the most direct observational indicators of recent mergers, offering a means to examine the impact of mergers on the photometric (Schweizer & Seitzer 1992;Tal et al 2009;Schawinski et al 2010;Kaviraj et al 2011;Hong et al 2015;Yoon & Lim 2020) and kinematic (Krajnović et al 2011;Duc et al 2015;Oh et al 2016;Yoon et al 2022;Bílek et al 2023) properties of ETGs.…”

Section: Introductionmentioning

confidence: 99%

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Shell-type Tidal Features Are More Frequently Detected in Slowly Rotating Early-type Galaxies than Stream- and Tail-type Features

Yoon,

Ko,

Chung

et al. 2024

ApJ

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To enhance our understanding of the impact of galaxy mergers on the kinematics of early-type galaxies (ETGs), we examine differences in specific stellar angular momentum within the half-light radius ( λ R e ) among ETGs with different types of tidal features and those without such features. This is accomplished by categorizing tidal features, which serve as direct evidence of recent mergers, into shells, streams, and tails, through deep images from the DESI Legacy Survey, and by using MaNGA data for the analysis of the kinematics of 1244 ETGs at z < 0.055. We find that ETGs with tidal features typically have reduced λ R e values that are lower by 0.12 dex than ETGs without tidal features. ETGs with shells contribute most to the reduction in λ R e . Consequently, nearly half of ETGs with shells are classified as slow rotators, a fraction that is more than twice as high as that of ETGs with tails or streams, and over three times higher than that of ETGs without tidal features. These trends generally remain valid even when ETGs are divided into several mass bins. Our findings support the idea that radial mergers, which are more effective at reducing λ R e than circular mergers, are more closely associated with the formation of shells rather than streams or tails. The detection of shells in slightly more massive ETGs compared to streams and tails may be attributed to the fact that massive satellite galaxies are more likely to be accreted through radial orbits, due to the nature of dynamical friction.

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Section: Resultssupporting

confidence: 94%

Section: Discussionsupporting

confidence: 75%

Section: Detection and Classification Of Tidal Featuresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Shell-type Tidal Features Are More Frequently Detected in Slowly Rotating Early-type Galaxies than Stream- and Tail-type Features

Yoon,

Ko,

Chung

et al. 2024

ApJ

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“…Note that our analysis is based on a sample of active star-forming galaxies that mostly include disks. Recently, Bílek et al (2023) reported that earlytype galaxies with lower rotational support tend to have more negative metallicity gradients.…”

Section: Discussionmentioning

confidence: 99%

Exploring the Gas-phase Metallicity Gradients of Star-forming Galaxies at Cosmic Noon

Cheng,

Giavalisco,

Simons

et al. 2024

ApJ

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We explore the relationships between the [O/H] gas-phase metallicity radial gradients and multiple galaxy properties for 238 star-forming galaxies at 0.6 < z < 2.6 selected from the CANDELS Lyα Emission at Reionization survey with stellar mass 8.5 < log M * / M ⊙ < 10.5 . The gradients cover the range from −0.11 to 0.22 dex kpc−1, with the median value close to 0. We reconstruct the nonparametric star formation histories (SFHs) of the galaxies with spectral energy distribution modeling using Prospector with more than 40 photometric bands from the Hubble Space Telescope, Spitzer, and ground-based facilities. In general, we find weak or no correlations between the metallicity gradients and most galaxy properties, including the mass-weighted age, recent star formation rate, dust attenuation, and morphology as quantified by both parametric and nonparametric diagnostics. We find a significant but moderate correlation between the gradients and the “evolutionary time,” a temporal metric that characterizes the evolutionary status of a galaxy, with flatter gradients observed in more evolved galaxies. Also, there is evidence that galaxies with multiple star formation episodes in their SFHs tend to develop more negative gas-phase metallicity gradients (higher [O/H] at the center). We conclude that gas kinematics, e.g., radial inflows and outflows, is likely an important process in setting the gas-phase metallicity gradients, in addition to the evolution of the SFH radial profile. Since the gradients are largely independent of the galaxies’ physical properties and only weakly dependent on their SFH, it would appear that the timescale of the gas kinematics is significantly shorter than the evolution of star formation.

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A stream come true: Connecting tidal tails, shells, streams, and planes with galaxy kinematics and formation history

Valenzuela,

Remus

2024

A&A

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The rapidly improving quality and resolution of both low surface brightness observations and cosmological simulations of galaxies enable us to address the important question of how the formation history is imprinted in the outer unrelaxed regions of galaxies, and to inspect the correlations of these imprints with another tracer of galaxy formation, the internal kinematics. Using the hydrodynamical cosmological simulation called Magneticum Pathfinder, we identified tidal tails, shells, streams, and satellite planes, and connected them to the amount of rotational support and the formation histories of the host galaxies. This presents the first combined statistical census considering all these four types of features in hydrodynamical cosmological simulations. Tidal features were visually classified from a three-dimensional rendering of the simulated galaxies by several scientists independently. Only features that were identified by at least half of the participating individuals were considered to be existing features. The data on satellite planes and kinematic properties of the simulated galaxies were taken from previous work. The results were compared to observations, especially from the survey. Generally, prominent features are much more common around elliptical than around disk galaxies. Shells are preferentially found around kinematically slowly rotating galaxies in both simulations and observations, while streams can be found around all types of galaxies, with a slightly higher probability to be present around less rotationally supported galaxies. Tails and satellite planes, however, appear independently of the internal kinematics of the central galaxy, indicating that they are formed through processes that have not (yet) affected the internal kinematics. Prolate rotators have the overall highest probability to exhibit tidal features, but the highest likelihood for a specific type of feature is found for galaxies with kinematically distinct cores (KDCs), nearly percent of which exhibit streams. As shells are formed through radial merger events while streams are remnants of circular merger infall, this suggests that the orbital angular momentum of the merger event plays a more crucial role in transforming the host galaxy than previously anticipated. The existence of a shell around a given slow rotator furthermore is a sign of a radial merger formation for this particular slow rotator because one-third of the galaxies with a shell were transformed into slow rotators by the merger event that also caused the shells. The appearance of a stream around a KDC is a direct indicator for the multiple merger formation pathway of that KDC as opposed to the major merger pathway.

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Origin of the differences in rotational support among early-type galaxies: The case of galaxies outside clusters

Cited by 6 publications

References 219 publications

Shell-type Tidal Features Are More Frequently Detected in Slowly Rotating Early-type Galaxies than Stream- and Tail-type Features

Shell-type Tidal Features Are More Frequently Detected in Slowly Rotating Early-type Galaxies than Stream- and Tail-type Features

Exploring the Gas-phase Metallicity Gradients of Star-forming Galaxies at Cosmic Noon

A stream come true: Connecting tidal tails, shells, streams, and planes with galaxy kinematics and formation history

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