J/MNRAS/477/1708 Origins of post-starburst galaxies at z<0.05 (Pawlik+, 2018)
The origins of post-starburst galaxies at z < 0.05.
Pawlik M.M., Taj Aldeen L., Wild V., Mendez-Abreu J., Lahen N.,
Johansson P.H., Jimenez N., Lucas W., Zheng Y., Walcher C.J., Rowlands K.
<Mon. Not. R. Astron. Soc., 477, 1708-1743 (2018)>
=2018MNRAS.477.1708P 2018MNRAS.477.1708P (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; Spectroscopy ; Morphology
Keywords: galaxies: evolution - galaxies: interactions - galaxies: starburst -
galaxies: stellar content - galaxies: structure
Abstract:
Post-starburst galaxies can be identified via the presence of
prominent Hydrogen Balmer absorption lines in their spectra. We
present a comprehensive study of the origin of strong Balmer lines in
a volume-limited sample of 189 galaxies with 0.01<z<0.05,
log(M*/M☉)>9.5 and projected axial ratio b/a>0.32. We explore
their structural properties, environments, emission lines, and star
formation histories, and compare them to control samples of
star-forming and quiescent galaxies, and simulated galaxy mergers.
Excluding contaminants, in which the strong Balmer lines are most
likely caused by dust-star geometry, we find evidence for three
different pathways through the post-starburst phase, with most events
occurring in intermediate-density environments: (1) a significant
disruptive event, such as a gas-rich major merger, causing a starburst
and growth of a spheroidal component, followed by quenching of the
star formation (70 per cent of post-starburst galaxies at
9.5<log(M*/M☉)<10.5 and 60 per cent at log(M*/M☉)>10.5);
(2) at 9.5<log(M*/M☉)<10.5, stochastic star formation in
blue-sequence galaxies, causing a weak burst and subsequent return to
the blue sequence (30 per cent); (3) at log(M*/M☉)>10.5, cyclic
evolution of quiescent galaxies which gradually move towards the
high-mass end of the red sequence through weak starbursts, possibly as
a result of a merger with a smaller gas-rich companion (40 per cent).
Our analysis suggests that active galactic nuclei (AGNs) are 'on' for
50 per cent of the duration of the post-starburst phase, meaning that
traditional samples of post-starburst galaxies with strict
emission-line cuts will be at least 50 per cent incomplete due to the
exclusion of narrow-line AGNs.
Description:
The spectroscopic catalogue of the SDSS (7th Data Release, SDSS DR7,
Abazajian et al., 2009ApJS..182..543A 2009ApJS..182..543A), containing the optical SED of
∼90000 galaxies, is a natural choice for selection of objects as rare
as low redshift post-starburst galaxies. In our study, we made use of
both spectroscopic and imaging data provided by the survey.
Additionally, we utilized the information regarding several spectral
lines available in the SDSS-MPA/JHU value added catalogue
(http://www.mpa-garching.mpg.de/SDSS and
http://home.strw.leidenuniv.nl/~jarle/SDSS/).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 211 189 Analysis results for the post-starburst galaxies
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 18 I18 --- specobjid SDSS specobjid
20- 25 A6 --- PSBtype Post-starburst type (defined in Section 2.2.1
of the paper)
27- 34 F8.5 [Msun] logM logarithmic stellar mass (1)
36- 41 F6.3 --- PC1 Spectral index PC1,
4000Å-break strength (2)
43- 48 F6.3 --- PC2 Spectral index PC2, excess Balmer absorption
above that expected based on the measured
4000Å-break strength (2)
50- 60 E11.8 --- log([NII]/Ha) Line ratio [NII]/Ha from the BPT diagram
(calculated from SDSS-MPAJHU)
62- 73 F12.8 --- log([OIII]/Hb) Line ratio [OIII]/Hb from the BPT diagram
(calculated from SDSS-MPAJHU);
75- 84 F10.6 0.1nm EQWHa Equivalent width of the Halpha emission line
(data from SDSS-MPAJHU)
86- 95 F10.6 --- Ha/Hb Balmer decrement (Halpha/Hbeta, calculated
from data from SDSS-MPAJHU)
97-102 F6.3 --- fM1 Fraction of recently formed stellar mass
(within the last 1Gyr) obtained using
STARLIGHT fits to the SDSS SED
104-109 F6.3 --- fM15 Fraction of recently formed stellar mass
(within the last 1.5Gyr) obtained using
STARLIGHT fits to the SDSS SED
111 I1 --- IMGFlag [0/1] Flag indicating the presence of a
contaminating source in the SDSS r-band
image
113-122 F10.6 --- n Sersic index (3)
124-133 F10.6 --- C Concentration index (3)
135-144 E10.8 --- A Light-weighted asymmetry (3)
(under a 180-degree rotation)
146-154 F9.7 --- As ? shape asymmetry (3)
(under a 180-degree rotation)
156-164 F9.7 --- As90 ? shape asymmetry (3)
(under a 90-degree rotation)
166-175 F10.6 --- G Gini index (3)
177-185 F9.6 --- M20 M20 statistics (3)
187-196 F10.6 --- Sigma5p Local galaxy density measurements (calculated
using photometric SDSS redshift
measurements)
198-207 F10.7 --- Sigma5s Local galaxy density measurements (calculated
using spectroscopic SDSS redshift
measurements)
209 I1 --- f_Sigma5p [0] Flag corresponding to the local galaxy
density measurement Sigma5p, related to
proximity to survey boarders
211 I1 --- f_Sigma5s [0/1] Flags corresponding to the local galaxy
density measurement Sigma5s, related to the
proximity to survey boarders
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Note (1): measured from 5-band photometry, SDSS-MPAJHU -
http:www.mpa-garching.mpg.deSDSS.
Note (2): full catalogue with errors available at
http:www-star.st-and.ac.uk∼vw8downloadsDR7PCA.html
Note (3): The morphological and structural parameters were measured using the
SDSS r-band images.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 03-Jun-2021