J/ApJ/862/2 Post-starburst galaxy ages from SDSS (French+, 2018)
Clocking the evolution of post-starburst galaxies: methods and first results.
French K.D., Yang Y., Zabludoff A.I., Tremonti C.A.
<Astrophys. J., 862, 2 (2018)>
=2018ApJ...862....2F 2018ApJ...862....2F
ADC_Keywords: Galaxy catalogs; Redshifts; Spectra, optical; Stars, ages;
Extinction
Keywords: catalogs ; galaxies: evolution ; galaxies: starburst ;
galaxies: stellar content ; methods: data analysis
Abstract:
Detailed modeling of the recent star formation histories (SFHs) of
post-starburst (or "E+A") galaxies is impeded by the degeneracy
between the time elapsed since the starburst ended (post-burst age),
the fraction of stellar mass produced in the burst (burst strength),
and the burst duration. To resolve this issue, we combine GALEX
ultraviolet photometry, SDSS photometry and spectra, and new stellar
population synthesis models to fit the SFHs of 532 post-starburst
galaxies. In addition to an old stellar population and a recent
starburst, 48% of the galaxies are best fit with a second recent
burst. Lower stellar mass galaxies (logM*/M☉<10.5) are more
likely to experience two recent bursts, and the fraction of their
young stellar mass is more strongly anticorrelated with their total
stellar mass. Applying our methodology to other, younger
post-starburst samples, we identify likely progenitors to our sample
and examine the evolutionary trends of molecular gas and dust content
with post-burst age. We discover a significant (4σ) decline,
with a 117-230Myr characteristic depletion time, in the molecular gas
to stellar mass fraction with the post-burst age. The implied rapid
gas depletion rate of 2-150M☉/yr cannot be due to current star
formation, given the upper limits on the current star formation rates
in these post- starbursts. Nor are stellar winds or supernova feedback
likely to explain this decline. Instead, the decline points to the
expulsion or destruction of molecular gas in outflows, a possible
smoking gun for active galactic nucleus feedback.
Description:
Our parent sample is drawn from the DR8 SDSS main galaxy spectroscopic
sample (Strauss+ 2002AJ....124.1810S 2002AJ....124.1810S & Aihara+ 2011ApJS..193...29A 2011ApJS..193...29A)
using the galaxy properties from the MPA-JHU catalogs (Brinchmann+
2004MNRAS.351.1151B 2004MNRAS.351.1151B & Tremonti+ 2004ApJ...613..898T 2004ApJ...613..898T). Notably, we
require that the SDSS spectra have no gaps over Hα or Hδ
in the rest frame.
For each of the post-starburst galaxies selected from the SDSS, we
search for matching Galaxy Evolution Explorer (GALEX; See II/312) NUV
and FUV detections using the GALEX GCAT All-Sky Survey Source Catalog
and GALEX Medium Imaging Survey Catalog. We search for galaxies within
4" of the SDSS positions.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 112 532 Post-burst ages
table2.dat 112 650 Shocked post-starburst galaxy ages
(Alatalo+ 2016, J/ApJS/224/38 sample)
table3.dat 112 11 Post-burst ages for
Rowlands+ (2015MNRAS.448..258R 2015MNRAS.448..258R) sample
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See also:
II/312 : GALEX-DR5 (GR5) sources from AIS and MIS (Bianchi+ 2011)
II/306 : The SDSS Photometric Catalog, Release 8 (Adelman-McCarthy+, 2011)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
J/ApJS/94/687 : Old stellar populations. V. (Worthey+, 1994)
J/ApJS/111/377 : Hγ & Hδ absorption features (Worthey+ 1997)
J/PASP/117/227 : Properties of 101 galaxies from the NFGS (Kewley+, 2005)
J/ApJ/706/599 : Hα and UV SFR in the local volume (Lee+, 2009)
J/MNRAS/414/940 : ATLAS3D project. IV. (Young+, 2011)
J/MNRAS/420/1684 : End of red sequence galaxies in Galaxy Zoo (Wong+, 2012)
J/MNRAS/431/2034 : SED of K+A galaxies from UV to mid-IR (Melnick+, 2013)
J/ApJ/793/38 : Palomar Transient Factory photometric obs. (Arcavi+, 2014)
J/A+A/562/A21 : AGN feedback from CO observations (Cicone+, 2014)
J/ApJS/210/3 : SDSS bulge, disk & stellar mass estimates (Mendel+, 2014)
J/ApJS/224/38 : SPOGS. I. SDSS Shocked POststarburst Galaxy cand.
(Alatalo+, 2016)
http://www.sdss3.org/ : SDSS-III home page
http://archive.stsci.edu/prepds/gcat/ : GALEX archive home page
Byte-by-byte Description of file: table[123].dat
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Bytes Format Units Label Explanations
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1- 10 F10.6 deg RAdeg SDSS DR8 Right Ascension (J2000)
12- 21 F10.6 deg DEdeg SDSS DR8 Declination (J2000)
23- 28 F6.4 --- zspec [0.002/0.4] SDSS DR8 spectroscopic redshift
30- 36 F7.1 [Msun] logM [8/11.4]?=-9999 log stellar mass (1)
38- 38 I1 --- SFH [1/2] Star Formation History;
Number of recent bursts (2)
40- 43 I4 Myr PBAge16 [-488/1601] Time since 90% of recent stars
formed, 16th percentile (Post-burst Age)
45- 48 I4 Myr PBAge50 [-428/1955] Time since 90% of recent stars
formed, median (Post-burst Age)
50- 53 I4 Myr PBAge84 [-368/2234] Time since 90% of recent stars
formed, 84th percentile (Post-burst Age)
55- 58 I4 Myr AgeSB16 [-28/2641] Time since starburst began,
16th percentile (Age since burst start)
60- 63 I4 Myr AgeSB50 [31/2995] Time since starburst began, median
65- 68 I4 Myr AgeSB84 [35/3274] Time since starburst began,
84th percentile
70- 73 I4 Myr Dur16 [25/1000] Burst Duration, 16th percentile (2)
75- 78 I4 Myr Dur50 [25/1000] Burst Duration, median (2)
80- 83 I4 Myr Dur84 [25/1000] Burst Duration, 84th percentile (2)
85- 88 F4.2 --- LF1 [0.04/1] Burst Light Fraction (if SFH=2 recent
bursts, light fraction for first burst only)
90- 93 F4.2 --- LF2 [0.1/1]? Second Burst Light Fraction,
if SFH=2 recent bursts (3)
95- 98 F4.2 --- MF16 [0/0.8] Burst Mass Fraction, 16th percentile
100-103 F4.2 --- MF50 [0/1] Burst Mass Fraction, median (4)
105-108 F4.2 --- MF84 [0/1] Burst Mass Fraction, 84th percentile
110-112 F3.1 mag Av [0/2] Extinction (includes foreground
extinction)
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Note (1): From SDSS MPA-JHU catalog, Aihara+ (2011ApJS..193...29A 2011ApJS..193...29A),
Brinchmann+ (2004MNRAS.351.1151B 2004MNRAS.351.1151B), Tremonti+ (2004ApJ...613..898T 2004ApJ...613..898T)
Note (2): If SFH=1 recent burst, burst tau; if SFH=2 recent bursts,
separation between bursts.
Note (3): If SFH=2, the burst mass fraction is the same for each recent burst.
Note (4): If SFH=2, burst mass fraction shown is the combined mass fraction
from both recent bursts.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 17-Jul-2019