ALMA resolves giant molecular clouds in a tidal dwarf galaxy
The result's identifiers
Result code in 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>
Result on the web
<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>
Alternative languages
Result language
angličtina
Original language name
ALMA resolves giant molecular clouds in a tidal dwarf galaxy
Original language description
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.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10308 - Astronomy (including astrophysics,space science)
Result continuities
Project
—
Continuities
—
Others
Publication year
2021
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Astronomy & Astrophysics
ISSN
0004-6361
e-ISSN
1432-0746
Volume of the periodical
645
Issue of the periodical within the volume
January
Country of publishing house
FR - FRANCE
Number of pages
20
Pages from-to
A97
UT code for WoS article
000613028700001
EID of the result in the Scopus database
2-s2.0-85100291627