J/A+A/705/A30 HectoMAP gal. single-Sersic mod. struct. param. (Pizzardo+, 2026)
Structural evolution of quiescent galaxies at intermediate redshifts
at UV and red rest-frame wavelengths.
Pizzardo M., Damjanov I., Sohn J., Geller M.J.
<Astron. Astrophys. 705, A30 (2026)>
=2026A&A...705A..30P 2026A&A...705A..30P (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, photometry ; Morphology ; Optical ; Models
Keywords: galaxies: evolution - galaxies: fundamental parameters -
galaxies: statistics - galaxies: stellar content - galaxies: structure
Abstract:
We derive structural parameters for a mass-limited sample
(M*>1010M☉) of 27000 quiescent galaxies with 0.2<z<0.6 using
grizy photometry from Subaru/Hyper Suprime-Cam and dense spectroscopy
from the HectoMAP survey. Based on Sersic profile fits in all five
bands, we model the wavelength dependence of the circularized
half-light radius (Re,c, a proxy for size) and Sersic index (n, a
proxy for central concentration) and estimate structural parameters in
two rest-frames: UV (3500Å, tracing young/metal-poor stellar
populations) and red (7000Å, tracing stellar mass distribution).
Combined with the stellar mass, redshift, and Dn4000, the estimates
of Re,c and n enable exploration of the evolution in the structural
properties - stellar mass correlations for quiescent galaxies for
different stellar population ages. At intermediate redshift, quiescent
galaxies at all stellar masses show a systematic decline in size and
rise in central concentration with rest-frame wavelength. These
structural variations are stronger for galaxies that recently joined
the quiescent population (newcomers, with 1.5<Dn4000<1.6) than for
the descendants of galaxies that are already quiescent at the survey
limit, z∼0.6 (aging/resident population). The combined evidence
supports inside-out quenching as the dominant mechanism halting star
formation during this epoch. The normalization of the size - stellar
mass relation (the typical size of a M*∼1011M☉ quiescent
galaxy) increases by ∼30% between z∼0.6 and z∼0.2 in the red
rest-frame and remains constant in the rest-frame UV. Size growth is
age-independent; newcomers are ∼20% larger than the aging population
across redshifts and rest-frames. Based on the Sersic index - stellar
mass relation in the UV, M*∼1011M☉ quiescent galaxies maintain
a constant central concentration (n∼4 for the aging population and n∼2
for newcomers). In the red rest-frame, both subpopulations have de
Vaucouleurs profiles after accounting for selection effects. The
larger sizes and disk-like UV profiles of newcomers link them to their
direct progenitors in the star-forming population. For the aging
population, the steady red rest-frame growth and elevated central
concentration in both red and UV rest-frames suggest minor mergers
with progressively redder satellites at lower redshifts as the primary
driver of galaxy evolution in the quiescent phase. Large samples of
low surface brightness galaxies available in forthcoming sensitive
large-area imaging surveys are ideal testbeds for this prediction.
Description:
Table 2 shows position, redshift, mass, and the Single-Sersic model
structural parameters for HectoMAP galaxies.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 376 103248 Single-Sersic model structural parameters for
HectoMAP galaxies
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See also:
J/ApJ/945/94 : HectoMAP: the complete redshift survey (DR2) (Sohn+, 2023)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- ID ID of the HectoMAP galaxies,
SDSS DR16 Object ID (1)
21- 29 F9.5 deg RAdeg Right ascension (J2000) (1)
31- 38 F8.5 deg DEdeg Declination (J2000) (1)
40- 47 F8.5 --- z Redshift (1)
49- 57 F9.5 --- e_z []?=- Error in redshift
(-1 when no error for the redshift)
59- 65 F7.3 [Msun] logM ?=- base 10 logarithm of stellar mass (1)
67- 73 F7.3 [Msun] e_logM ?=- Error for logM
75- 84 F10.4 arcsec Reg ?=- Half-light radius along the galaxy
major axis in g-band
86- 94 F9.4 arcsec e_Reg ?=- Error in Reg
96-103 F8.4 --- b/ag ?=- Axis ratio in g-band
105-113 F9.4 --- e_b/ag ?=- Error in b/ag
115-121 F7.3 --- ng ?=- Sersic index in g-band
123-130 F8.3 --- e_ng ?=- Error in ng
132-141 F10.4 arcsec Rer ?=- Half-light radius along the galaxy
major axis in r-band
143-156 F14.4 arcsec e_Rer ?=- Error in Rer
158-165 F8.4 --- b/ar ?=- Axis ratio in r-band
167-181 F15.4 --- e_b/ar ?=- Error in b/ar
183-189 F7.3 --- nr ?=- Sersic index in r-band
191-198 F8.3 --- e_nr ?=- Error in nr
200-207 F8.4 arcsec Rei ?=- Half-light radius along the galaxy
major axis in i-band
209-216 F8.4 arcsec e_Rei ?=- Error in Rei
218-225 F8.4 --- b/ai ?=- Axis ratio in i-band
227-235 F9.4 --- e_b/ai ?=- Error in b/ai
237-243 F7.3 --- ni ?=- Sersic index in i-band
245-252 F8.3 --- e_ni ?=- Error in ni
254-262 F9.4 arcsec Rez ?=- Half-light radius along the galaxy
major axis in z-band
264-280 F17.4 arcsec e_Rez ?=- Error in Rez
282-289 F8.4 --- b/az ?=- Axis ratio in z-band
291-305 F15.4 --- e_b/az ?=- Error in b/az
307-313 F7.3 --- nz ?=- Sersic index in z-band
315-322 F8.3 --- e_nz ?=- Error in nz
324-331 F8.4 arcsec Rey ?=- Half-light radius along the galaxy
major axis in y-band
333-340 F8.4 arcsec e_Rey ?=- Error in Rey
342-349 F8.4 --- b/ay ?=- Axis ratio in y-band
351-359 F9.4 --- e_b/ay ?=- Error in b/ay
361-367 F7.3 --- ny ?=- Sersic index in y-band
369-376 F8.3 --- e_ny ?=- Error in ny
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Note (1): matching Sohn et al., 2023ApJ...945...94S 2023ApJ...945...94S, Cat. J/ApJ/945/94.
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Acknowledgements:
Michele Pizzardo, michele.pizzardo(at)gmail.com
(End) Patricia Vannier [CDS] 11-Nov-2025