Bibcode
Rosado-Belza, D.; Lisenfeld, U.; Hibbard, J.; Kniermann, K.; Ott, J.; Verley, S.; Boquien, M.; Jarrett, T.; Xu, C. K.
Bibliographical reference
Astronomy and Astrophysics, Volume 623, id.A154, 16 pp.
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3
2019
Journal
Citations
2
Refereed citations
1
Description
Minor mergers play a crucial role in galaxy evolution. UGC 10214 (the
Tadpole galaxy) is a prime example of this process in which a dwarf
galaxy has interacted with a large spiral galaxy ˜250 Myr ago and
produced a perturbed disc and a giant tidal tail. We used a
multi-wavelength dataset that partly consists of new observations
(Hα, HI, and CO) and partly of archival data to study the present
and past star formation rate (SFR) and its relation to the gas and
stellar mass at a spatial resolution down to 4 kpc. UGC 10214 is a
high-mass (stellar mass M⋆ = 1.28 ×
1011 M⊙) galaxy with a low gas fraction
(Mgas/M⋆ = 0.24), a high molecular gas
fraction (MH2/MHI = 0.4), and a modest
SFR (2-5 M⊙ yr-1). The global SFR compared to
its stellar mass places UGC 10214 on the galaxy main sequence (MS). The
comparison of the molecular gas mass and current SFR gives a molecular
gas depletion time of about ˜2 Gyr (based on Hα), comparable
to those of normal spiral galaxies. Both from a comparison of the
Hα emission, tracing the current SFR, and far-ultraviolet (FUV)
emission, tracing the recent SFR during the past tens of Myr, and also
from spectral energy distribution fitting with CIGALE, we find that the
SFR has increased by a factor of about 2-3 during the recent past. This
increase is particularly noticeable in the centre of the galaxy where a
pronounced peak of the Hα emission is visible. A pixel-to-pixel
comparison of the SFR, molecular gas mass, and stellar mass shows that
the central region has had a depressed FUV-traced SFR compared to the
molecular gas and the stellar mass, whereas the Hα-traced SFR
shows a normal level. The atomic and molecular gas distribution is
asymmetric, but the position-velocity diagram along the major axis shows
a pattern of regular rotation. We conclude that the minor merger has
most likely caused variations in the SFR in the past that resulted in a
moderate increase of the SFR, but it has not perturbed the gas
significantly so that the molecular depletion time remains normal.
Data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr
(ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/623/A154
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