ALMA resolves giant molecular clouds in a tidal dwarf galaxy

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F21%3A00553711" target="_blank" >RIV/67985815:_____/21:00553711 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1051/0004-6361/202038955" target="_blank" >https://doi.org/10.1051/0004-6361/202038955</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202038955" target="_blank" >10.1051/0004-6361/202038955</a>

Jazyk výsledku

angličtina

Název v původním jazyce

ALMA resolves giant molecular clouds in a tidal dwarf galaxy

Popis výsledku v původním jazyce

Tidal dwarf galaxies (TDGs) are gravitationally bound condensations of gas and stars that formed during galaxy interactions. Here we present multi-configuration ALMA observations of J1023+1952, a TDG in the interacting system Arp 94, where we resolved CO(2-1) emission down to giant molecular clouds (GMCs) at 0.64 '' similar to 45 pc resolution. We find a remarkably high fraction of extended molecular emission (similar to 80-90%), which is filtered out by the interferometer and likely traces diffuse gas. We detect 111 GMCs that give a similar mass spectrum as those in the Milky Way and other nearby galaxies (a truncated power law with a slope of -1.76 +/- 0.13). We also study Larson's laws over the available dynamic range of GMC properties (similar to 2 dex in mass and similar to 1 dex in size): GMCs follow the size-mass relation of the Milky Way, but their velocity dispersion is higher such that the size-linewidth and virial relations appear super-linear, deviating from the canonical values. The global molecular-to-atomic gas ratio is very high (similar to 1) while the CO(2-1)/CO(1-0) ratio is quite low (similar to 0.5), and both quantities vary from north to south. Star formation predominantly takes place in the south of the TDG, where we observe projected offsets between GMCs and young stellar clusters ranging from similar to 50 pc to similar to 200 pc, the largest offsets correspond to the oldest knots, as seen in other galaxies. In the quiescent north, we find more molecular clouds and a higher molecular-to-atomic gas ratio (similar to 1.5), atomic and diffuse molecular gas also have a higher velocity dispersion there. Overall, the organisation of the molecular interstellar medium in this TDG is quite different from other types of galaxies on large scales, but the properties of GMCs seem fairly similar, pointing to near universality of the star-formation process on small scales.

Název v anglickém jazyce

ALMA resolves giant molecular clouds in a tidal dwarf galaxy

Popis výsledku anglicky

Tidal dwarf galaxies (TDGs) are gravitationally bound condensations of gas and stars that formed during galaxy interactions. Here we present multi-configuration ALMA observations of J1023+1952, a TDG in the interacting system Arp 94, where we resolved CO(2-1) emission down to giant molecular clouds (GMCs) at 0.64 '' similar to 45 pc resolution. We find a remarkably high fraction of extended molecular emission (similar to 80-90%), which is filtered out by the interferometer and likely traces diffuse gas. We detect 111 GMCs that give a similar mass spectrum as those in the Milky Way and other nearby galaxies (a truncated power law with a slope of -1.76 +/- 0.13). We also study Larson's laws over the available dynamic range of GMC properties (similar to 2 dex in mass and similar to 1 dex in size): GMCs follow the size-mass relation of the Milky Way, but their velocity dispersion is higher such that the size-linewidth and virial relations appear super-linear, deviating from the canonical values. The global molecular-to-atomic gas ratio is very high (similar to 1) while the CO(2-1)/CO(1-0) ratio is quite low (similar to 0.5), and both quantities vary from north to south. Star formation predominantly takes place in the south of the TDG, where we observe projected offsets between GMCs and young stellar clusters ranging from similar to 50 pc to similar to 200 pc, the largest offsets correspond to the oldest knots, as seen in other galaxies. In the quiescent north, we find more molecular clouds and a higher molecular-to-atomic gas ratio (similar to 1.5), atomic and diffuse molecular gas also have a higher velocity dispersion there. Overall, the organisation of the molecular interstellar medium in this TDG is quite different from other types of galaxies on large scales, but the properties of GMCs seem fairly similar, pointing to near universality of the star-formation process on small scales.

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

2021

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

645

Číslo periodika v rámci svazku

January

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

20

Strana od-do

A97

Kód UT WoS článku

000613028700001

EID výsledku v databázi Scopus

2-s2.0-85100291627