Massive Early-Type Galaxies in the HSC-SSP: Flux Fraction of Tidal Features and Merger Rates. (arXiv:2207.14320v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Huang_Q/0/1/0/all/0/1">Qifeng Huang</a> (USTC), <a href="http://arxiv.org/find/astro-ph/1/au:+Fan_L/0/1/0/all/0/1">Lulu Fan</a> (USTC)

Here we present a statistical study on tidal features around massive
early-type galaxies (ETGs). Utilizing the imaging data of the Hyper Suprime-Cam
Subaru Strategic Program (HSC-SSP), we measure the flux fraction of tidal
features ($f_{rm tidal}$) in 2649 ETGs with stellar mass
$M_*>10^{11}M_{odot}$ and redshift $0.05<z<0.15$ using automated techniques.
The Wide-layer of HSC-SSP reaches a depth of $sim 28.5$ mag arcsec$^{-2}$ in
$i$-band. Under this surface brightness limit, we find that about 28 % of these
galaxies harbor prominent tidal features with $f_{rm tidal}>1%$, among which
the number of ETGs decreases exponentially with $f_{rm tidal}$, with a
logarithmic slope of $sim100$. Within the stellar mass range we probe, we note
that $f_{rm tidal}$ increases by a factor of 2 from
$M_*approx10^{11}M_{odot}$ to $M_*approx10^{12}M_{odot}$. We also perform
pair-count to estimate the merger rate of these massive ETGs. Combining the
merger rates with $f_{rm tidal}$, we estimate that the typical lifetime of
tidal features is $sim$ 3 Gyr, consistent with previous studies.

Here we present a statistical study on tidal features around massive
early-type galaxies (ETGs). Utilizing the imaging data of the Hyper Suprime-Cam
Subaru Strategic Program (HSC-SSP), we measure the flux fraction of tidal
features ($f_{rm tidal}$) in 2649 ETGs with stellar mass
$M_*>10^{11}M_{odot}$ and redshift $0.05<z<0.15$ using automated techniques.
The Wide-layer of HSC-SSP reaches a depth of $sim 28.5$ mag arcsec$^{-2}$ in
$i$-band. Under this surface brightness limit, we find that about 28 % of these
galaxies harbor prominent tidal features with $f_{rm tidal}>1%$, among which
the number of ETGs decreases exponentially with $f_{rm tidal}$, with a
logarithmic slope of $sim100$. Within the stellar mass range we probe, we note
that $f_{rm tidal}$ increases by a factor of 2 from
$M_*approx10^{11}M_{odot}$ to $M_*approx10^{12}M_{odot}$. We also perform
pair-count to estimate the merger rate of these massive ETGs. Combining the
merger rates with $f_{rm tidal}$, we estimate that the typical lifetime of
tidal features is $sim$ 3 Gyr, consistent with previous studies.

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