Do spiral arms enhance star formation efficiency?

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A90106%2F24%3A00617541" target="_blank" >RIV/67985815:90106/24:00617541 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1051/0004-6361/202449733" target="_blank" >https://doi.org/10.1051/0004-6361/202449733</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202449733" target="_blank" >10.1051/0004-6361/202449733</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Do spiral arms enhance star formation efficiency?

Popis výsledku v původním jazyce

Spiral arms, as those of our own Milky Way, are some of the most spectacular features in disc galaxies. It has been argued that star formation should proceed more efficiently in spiral arms as a result of gas compression. Yet, observational studies have so far yielded contradictory results. Here, we examine arm/interarm surface density contrasts at similar to 100 pc resolution in 28 spiral galaxies from the PHANGS survey. We find that the arm/interarm contrast in stellar mass surface density (Sigma star) is very modest, typically a few tens of percent. This is much smaller than the contrasts measured for molecular gas (Sigma(mol)) or star formation rate (Sigma(SFR)) surface density, which typically reach a factor of similar to 2 3. However, Sigma(mol) and Sigma(SFR) contrasts show a significant correlation with the enhancement in Sigma star, suggesting that the small stellar contrast largely dictates the stronger accumulation of gas and star formation. All these contrasts increase for grand-design spirals compared to multi-armed and flocculent systems (and for galaxies with high stellar mass). The median star formation efficiency (SFE) of the molecular gas is 16% higher in spiral arms than in interarm regions, with a large scatter, and the contrast increases significantly (median SFE contrast 2.34) for regions of particularly enhanced stellar contrast (Sigma star contrast > 1.97). The molecular-to-atomic gas ratio (Sigma(mol)/Sigma(atom)) is higher in spiral arms, pointing to a transformation of atomic to molecular gas. As a consequence, the total gas contrast (Sigma(mol) + Sigma(atom)) slightly drops compared to Sigma(mol) (median 4% lower, working at similar to kpc resolution), while the SFE contrast increases when we include atomic gas (median 8% higher than for Sigma(mol)). The contrasts show important fluctuations with galactocentric radius. We confirm that our results are robust against a number of effects, such as spiral mask width, tracers, resolution, and binning. In conclusion, the boost in the SFE of molecular gas in spiral arms is generally modest or absent, except for locations with exceptionally large stellar contrasts.

Název v anglickém jazyce

Do spiral arms enhance star formation efficiency?

Popis výsledku anglicky

Spiral arms, as those of our own Milky Way, are some of the most spectacular features in disc galaxies. It has been argued that star formation should proceed more efficiently in spiral arms as a result of gas compression. Yet, observational studies have so far yielded contradictory results. Here, we examine arm/interarm surface density contrasts at similar to 100 pc resolution in 28 spiral galaxies from the PHANGS survey. We find that the arm/interarm contrast in stellar mass surface density (Sigma star) is very modest, typically a few tens of percent. This is much smaller than the contrasts measured for molecular gas (Sigma(mol)) or star formation rate (Sigma(SFR)) surface density, which typically reach a factor of similar to 2 3. However, Sigma(mol) and Sigma(SFR) contrasts show a significant correlation with the enhancement in Sigma star, suggesting that the small stellar contrast largely dictates the stronger accumulation of gas and star formation. All these contrasts increase for grand-design spirals compared to multi-armed and flocculent systems (and for galaxies with high stellar mass). The median star formation efficiency (SFE) of the molecular gas is 16% higher in spiral arms than in interarm regions, with a large scatter, and the contrast increases significantly (median SFE contrast 2.34) for regions of particularly enhanced stellar contrast (Sigma star contrast > 1.97). The molecular-to-atomic gas ratio (Sigma(mol)/Sigma(atom)) is higher in spiral arms, pointing to a transformation of atomic to molecular gas. As a consequence, the total gas contrast (Sigma(mol) + Sigma(atom)) slightly drops compared to Sigma(mol) (median 4% lower, working at similar to kpc resolution), while the SFE contrast increases when we include atomic gas (median 8% higher than for Sigma(mol)). The contrasts show important fluctuations with galactocentric radius. We confirm that our results are robust against a number of effects, such as spiral mask width, tracers, resolution, and binning. In conclusion, the boost in the SFE of molecular gas in spiral arms is generally modest or absent, except for locations with exceptionally large stellar contrasts.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

—

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Svazek periodika

687

Číslo periodika v rámci svazku

July

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

26

Strana od-do

A293

Kód UT WoS článku

001275047000001

EID výsledku v databázi Scopus

2-s2.0-85199498536