J/ApJ/919/134 SDSS shocked post-starburst gal. with HST obs. (Sazonova+, 2021)
Are all post-starbursts mergers? HST reveals hidden disturbances in the majority
of PSBs.
Sazonova E., Alatalo K., Rowlands K., Deustua S.E., French K.D.,
Heckman T., Lanz L., Lisenfeld U., Luo Y., Medling A., Nyland K.,
Otter J.A., Petric A.O., Snyder G.F., Urry C.M.
<Astrophys. J., 919, 134 (2021)>
=2021ApJ...919..134S 2021ApJ...919..134S
ADC_Keywords: Galaxies; Photometry, HST; Morphology; Redshifts; Optical;
Photometry, infrared; Ultraviolet
Keywords: Post-starburst galaxies ; Galaxies ; Galaxy classification systems ;
Galaxy mergers ; Galaxy evolution ; Galaxy quenching ;
Galaxy structure ; Galactic and extragalactic astronomy ;
Galaxy physics
Abstract:
How do galaxies transform from blue, star-forming spirals to red,
quiescent early-type galaxies? To answer this question, we analyzed a
set of 26 gas-rich, shocked post-starburst galaxies with Hubble Space
Telescope (HST) imaging in B, I, and H bands and Sloan Digital Sky
Survey (SDSS) i-band imaging of similar depth but lower resolution. We
found that post-starbursts in our sample have intermediate
morphologies between disk- and bulge-dominated (Sersic
n=1.7-0.0+0.3) and have red bulges, likely due to dust obscuration
in the cores. A majority of galaxies in our sample are more
morphologically disturbed than regular galaxies (88%, corresponding to
>3σ significance) when observed with HST, with asymmetry and
Sersic residual flux fraction being the most successful measures of
disturbance. Most disturbances are undetected at the lower resolution
of SDSS imaging. Although ∼27% galaxies are clear merger remnants, we
found that disturbances in another ∼30% of the sample are internal,
caused by small-scale perturbations or dust substructures rather than
tidal features, and require high-resolution imaging to detect. We
found 2.8σ evidence that asymmetry features fade on timescales
∼200Myr, and may vanish entirely after ∼750Myr, so we do not rule out
a possible merger origin of all post-starbursts given that asymmetric
features may have already faded. This work highlights the importance
of small-scale disturbances, detected only in high-resolution imaging,
in understanding structural evolution of transitioning galaxies.
Description:
We analyzed a subset of shocked post-starburst galaxies (SPOGs;
Alatalo+ 2016, J/ApJS/224/38) in this study.
To further study the morphology and dust content of 47 CO-detected
SPOGs (Alatalo+ 2016, 2016ApJ...827..106A 2016ApJ...827..106A), we have obtained HST
imaging for 26 galaxies as part of the snapshot program
(Proposal 14649, PI: Alatalo). These galaxies (HST-SPOGs) were
observed using HST Wide-Field Camera 3 (WFC3) with F438W (B),
F814W (I), and F160W (H) filters in order to capture the dust
extinction and study morphology at high resolution.
We obtained spectroscopic redshifts for all HST-SPOGs from the NYU
Value-Added Catalog (NYU-VAGC; Blanton+ 2005AJ....129.2562B 2005AJ....129.2562B).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 102 26 Summary of HST shocked post-starburst galaxies
(HST-SPOGs) sample properties and imaging
data used in this work
table6.dat 195 208 Morphological measurements for HST-SPOGs,
star-forming and quiescent galaxies calculated
in this work
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
II/342 : Hubble Source Catalog (V1 and V2) (Whitmore+, 2016)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
II/342 : Hubble Source Catalog (V1 and V2) (Whitmore+, 2016)
II/335 : Revised catalog of GALEX UV sources (GUVcat_AIS GR6+7) (Bianchi+ 2017)
J/ApJS/107/1 : Morphologies of distant galaxies II (Abraham+ 1996)
J/ApJS/147/1 : Classification of nearby galaxies (Conselice+, 2003)
J/AJ/128/163 : Galaxy morphological classification (Lotz+, 2004)
J/AJ/132/321 : Morphology of narrow-line Seyfert 1 galaxies (Deo+, 2006)
J/MNRAS/405/783 : Passive red spirals in Galaxy Zoo (Masters+, 2010)
J/MNRAS/411/2439 : Coma Treasury Survey. Structural parameters (Hoyos+, 2011)
J/MNRAS/414/940 : ATLAS3D project. IV. (Young+, 2011)
J/ApJS/206/10 : CANDELS multiwavelength catalog (Galametz+, 2013)
J/MNRAS/435/2835 : Morphological types from Galaxy Zoo 2 (Willett+, 2013)
J/A+A/562/A21 : AGN feedback from CO observations (Cicone+, 2014)
J/ApJS/219/8 : SFR for WISE + SDSS spectroscopic galaxies (Chang+, 2015)
J/MNRAS/454/1886 : Galaxy morph. with Illustris Simulation (Snyder+, 2015)
J/ApJS/224/38 : SPOGS. I. SDSS Shocked POststarburst Gal. (Alatalo+, 2016)
J/MNRAS/481/5580 : Formation sequence of S0 galaxies (Fraser-McKelvie+, 2018)
J/ApJ/862/2 : Post-starburst galaxy ages from SDSS (French+, 2018)
J/MNRAS/477/1708 : Origins of post-starburst galaxies at z<0.05 (Pawlik+, 2018)
J/MNRAS/486/4290 : AGN-driven winds through IR emission. II. (Baron+, 2019)
http://www.sdss.org/ : SDSS home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name IAU name (JHHMMSS+DDMMSS)
16- 19 I4 --- ID [1/1014] Identifier in
Alatalo+ 2016, J/ApJS/224/38
21- 22 I2 h RAh Hour of right ascension (J2000)
24- 25 I2 min RAm Minute of right ascension (J2000)
27- 31 F5.2 s RAs Second of right ascension (J2000)
33 A1 --- DE- Sign of declination (J2000)
34- 35 I2 deg DEd Degree of declination (J2000)
37- 38 I2 arcmin DEm Arcminute of declination (J2000)
40- 41 I2 arcsec DEs Arcsecond of declination (J2000)
43- 47 F5.3 --- z [0.033/0.191] SDSS spectroscopic redshift
49- 52 F4.1 [Msun] logM50 [10.1/11.2] Log of stellar mass from
Chang+ 2015, J/ApJS/219/8
54- 56 F3.1 [Msun] e_logM50 [0/0.2] Lower uncertainty on logM50
58- 60 F3.1 [Msun] E_logM50 [0/0.2] Upper uncertainty on logM50
62- 65 F4.2 mag NUV-r [2.25/5.1]? NUV-r color where the galaxy
is detected with GALEX
67- 69 I3 Myr tau [-94/692] PSB age from
French+ 2018, J/ApJ/862/2
71- 73 I3 Myr e_tau [5/270] Lower uncertainty on tau
75- 77 I3 Myr E_tau [4/531] Upper uncertainty on tau
79- 82 F4.2 --- fgas [0.03/0.45] Molecular gas fraction from
Alatalo+ 2016ApJ...827..106A 2016ApJ...827..106A
84- 87 F4.1 mag/arcsec2 F438W [22.4/24] 1σ sky background AB flux
of HST F438W imaging
89- 92 F4.1 mag/arcsec2 F814W [22.3/25.1] 1σ sky background AB flux
of HST F814W imaging
94- 97 F4.1 mag/arcsec2 F160W [23.1/23.8] 1σ sky background AB flux
of HST F160W imaging
99- 102 F4.1 mag/arcsec2 i [22.2/24.9] 1σ sky background AB flux
of SDSS i-band imaging
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name IAU name (JHHMMSS+DDMMSS)
16- 22 F7.3 deg RAdeg Right Ascension (J2000)
24- 29 F6.3 deg DEdeg [-1.8/60] Declination (J2000)
31- 36 F6.3 [Msun] logM [10/11.2] Log stellar mass
38- 42 F5.3 --- z [0.028/0.2] Spectroscopic redshift
44- 51 A8 --- Set Sample identifier (1)
53- 56 A4 --- Survey Survey origin (2)
58- 62 A5 --- Filt Filter used
64- 69 F6.3 mag/arcsec2 Depth [22.17/24.11] The 1σ sky brightness
71- 75 F5.3 arcsec PSF [0.07/1.9] FWHM of PSF or seeing
77- 81 F5.3 arcsec/pix Scale [0.04/0.4] Image pixel scale
83- 96 A14 --- qg Mass- and redshift- matched comparison
quiescent galaxy (JHHMMSS+DDMMSS)
98- 111 A14 --- sfg Mass- and redshift- matched comparison
star-forming galaxy (JHHMMSS+DDMMSS)
113- 118 F6.3 --- Asy [-0.24/0.6] Asymmetry
120- 124 F5.3 --- Shape [0.1/2] Shape asymmetry
126- 130 F5.3 --- Conc [0.44/5.7] Concentration
132- 136 F5.3 --- Gini [0.42/0.8] Gini disturbance index
138- 143 F6.3 --- M20 [-3.14/-0.76] M20 disturbance value
145- 150 F6.3 --- GiniB [-1.31/1.52] Bulge Gini/M20
disturbance index
152- 157 F6.3 --- GiniM [-0.2/0.18] Merger Gini/M20
disturbance index
159- 164 F6.3 --- n [0.29/20] Sersic index
166- 170 F5.3 --- InRff [0.007/0.7] Inner residual flux fraction
172- 176 F5.3 --- Rff [0.012/0.44] Residual flux fraction
178- 182 F5.3 --- OutRff [0.004/0.42]? Outer residual flux
fraction (3)
184- 188 F5.3 --- BtoL [0/1] Bulge-to-total light ratio
190- 195 F6.3 kpc RPet [0.38/12.9] Petrosian radius
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Note (1): Sample as follows:
HST-SPOG = shocked post-starburst galaxies from this work (104 occurrences)
QG = comparison quiescent (52 occurrences)
SFG = comparison star-forming (52 occurrences)
Note (2): Survey as follows:
HST = (130 occurrences)
SDSS = (78 occurrences)
Note (3): A blank indicates a infinite result.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 02-Feb-2023