J/MNRAS/499/1406 Role of bars in enhancing central star formation (Lin+, 2020)
SDSS-IV MaNGA: the indispensable role of bars in enhancing the central star
formation of low-z galaxies.
Lin L., Li C., Du C., Wang E., Xiao T., Bureau M., Fraser-McKelvie A.,
Masters K., Lin L., Wake D., Hao L.
<Mon. Not. R. Astron. Soc., 499, 1406-1423 (2020)>
=2020MNRAS.499.1406L 2020MNRAS.499.1406L (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Star Forming Region ; Equivalent widths ;
Spectra, optical
Keywords: galaxies: bar - galaxies: evolution - galaxies: formation -
galaxies: star formation - galaxies: structure
Abstract:
We analyse two-dimensional maps and radial profiles of EW(Hα),
EW(HδA), and Dn(4000) of low-redshift galaxies using
integral field spectroscopy from the MaNGA survey. Out of ∼1400 nearly
face-on late-type galaxies with a redshift z<0.05, we identify 121
"turnover" galaxies that each have a central upturn in EW(Hα),
EW(HδA), and/or a central drop in Dn(4000), indicative of
ongoing/recent star formation. The turnover features are found mostly
in galaxies with a stellar mass above ∼1010M☉ and NUV-r colour
less than ∼5. The majority of the turnover galaxies are barred, with a
bar fraction of 89±3 per cent. Furthermore, for barred galaxies, the
radius of the central turnover region is found to tightly correlate
with one-third of the bar length. Comparing the observed and the
inward extrapolated star formation rate surface density, we estimate
that the central SFR have been enhanced by an order of magnitude.
Conversely, only half of the barred galaxies in our sample have a
central turnover feature, implying that the presence of a bar is not
sufficient to lead to a central SF enhancement. We further examined
the SF enhancement in paired galaxies, as well as the local
environment, finding no relation. This implies that the environment is
not a driving factor for central SF enhancement in our sample. Our
results reinforce both previous findings and theoretical expectation
that galactic bars play a crucial role in the secular evolution of
galaxies by driving gas inflow and enhancing the star formation and
bulge growth in the centre.
Description:
As one of the three key programs of the fourth-generation of SDSS
(SDSS-IV; Blanton et al. 2017AJ....154...28B 2017AJ....154...28B), MaNGA is an
integral-field unit (IFU) spectroscopic survey (Bundy et al.
2015ApJ...798....7B 2015ApJ...798....7B), aiming to achieve kpc-scale spatially resolved
IFU datacubes for about 10000 nearby galaxies.
In this work, we use the internal data release of MaNGA, the MaNGA
Product Launch 7 (MPL-7), that includes DRP and DAP products for 4672
galaxies and is identical to the MaNGA data released with the SDSS
Data Release 15 (DR15; Aguado et al. 2019ApJS..240...23A 2019ApJS..240...23A).
For our study, we select a sample of galaxies from the MPL-7 as
follows. First, we select nearly face-on galaxies, with minor-to-major
axial ratio b/a>0.5. Secondly, we restrict ourselves to relatively low
redshifts z<0.05. Third, we select late-type galaxies by requiring
T-type>0. The morphological classification was taken from Dominguez
Sanchez et al. (2018MNRAS.476.3661D 2018MNRAS.476.3661D, Cat. J/MNRAS/476/3661). Finally,
we make use of the MPL-7 version of the close pair galaxy catalogue to
exclude 78 galaxies that are merging systems at the final coalescence
stage. These restrictions give rise to a sample of 1452 late-type
galaxies.
We visually examined the SDSS gri images of all 1425 galaxies in our
sample and constructed our barred galaxy sample consisting of 252
galaxies. See Table 2 for details.
We also searched for turnover galaxies in our sample and found 121
galaxies having a central upturn in EW(Hα), EW(HδA),
and/or a central drop in Dn(4000). See Table 3 for details.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 43 252 Measurements of barred galaxies
table3.dat 63 121 Turnover property measurements
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See also:
J/AJ/154/86 : MaNGA catalog, DR15 (Wake+, 2017)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- ID MaNGA identifier
12- 16 F5.2 arcsec rbar Bar length
18- 21 F4.2 arcsec e_rbar Error on rbar
23- 26 F4.2 --- ebar Bar ellipticity
28- 31 F4.2 --- e_ebar Error on ebar
33- 38 F6.2 deg PAbar Bar position angle
40- 43 F4.2 deg e_PAbar Error on PAbar
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- ID MaNGA identifier
12- 15 F4.2 arcsec Rt Turnover radius Rt
17- 20 F4.2 arcsec e_Rt Error on Rt
22- 26 F5.2 [0.1nm] DEWHa ? Logarithm of the EWHα enhancement
28- 31 F4.2 [0.1nm] e_DEWHa ? Error on DEWHa
33- 37 F5.2 0.1nm DEWHd EWHδ enhancement
39- 42 F4.2 0.1nm e_DEWHd Error on DEWHd
44- 48 F5.2 --- DDn4000 Dn(4000) drop
50- 53 F4.2 --- e_DDn4000 Error on DDn4000
55- 58 F4.2 [Msun/yr] DlogSFR ? Logarithm of the star formation rate
enhancement within turnover radius
60- 63 F4.2 [Msun/yr] e_DlogSFR ? Error on DlogSFR
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History:
From electronic version of the journal
References:
Lin et al., Paper I 2017ApJ...838..105L 2017ApJ...838..105L
(End) Ana Fiallos [CDS] 17-Aug-2023