Dwarf Galaxy Discoveries from the KMTNet Supernova Program. II. The NGC 3585 Group and Its Dynamical State

Hong Soo Park, Dae Sik Moon, Dennis Zaritsky, Sang Chul Kim, Youngdae Lee, Sang Mok Cha, Yongseok Lee

Research output: Contribution to journalArticle

Abstract

We present our discovery and analysis of dwarf galaxies in the NGC 3585 galaxy group by the Korea Microlensing Telescope Network (KMTNet) Supernova Program. Using deep stack images reaching ≃28 mag arcsec-2 in BVI, we discovered 46 dwarf galaxy candidates distributed in a field of 7 square degrees. The dwarf galaxy candidates exhibit a central surface brightness as faint as μ 0,V = 26.2 mag arcsec-2, with effective radii larger than 150 pc and total absolute magnitudes brighter than M V ≈ -10 mag, if at the distance of NGC 3585. The dwarf galaxy surface number density decreases with projected distance from NGC 3585. We estimate the background contamination to be about 20% based both on the number density profile and on diffuse galaxy counts in a control field. The dwarf galaxy colors and Sérsic structural parameters are consistent with those found for other dwarf galaxies. Unusually, there is no indication of a change in color or brightness in the dwarf galaxy candidates with projected distance from the group center. Approximately 20% of the candidates contain an unresolved nucleus. The nucleated fraction is larger for brighter (and redder) galaxies, but is independent of distance from the group center. We identify four ultra-diffuse galaxy candidates, all near the group center. We interpret these spatial properties as suggesting that the NGC 3585 group might be dynamically younger than the typical group. The galaxy luminosity function of the NGC 3585 group has a faint-end slope of α ≈ -1.39, which is roughly consistent with the slopes found for other nearby groups. The possible dependence of the slope on global group properties is still unclear and continues to motivate our homogeneous deep survey of dozens of nearby groups.

Original languageEnglish (US)
Article number88
JournalAstrophysical Journal
Volume885
Issue number1
DOIs
StatePublished - Nov 1 2019

Fingerprint

Korea
dwarf galaxies
supernovae
telescopes
galaxies
slopes
brightness
color
programme
galactic clusters
indication
contamination
luminosity
nuclei
radii
estimates
profiles

Keywords

  • galaxies: dwarf
  • galaxies: groups: individual (NGC 3585)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Dwarf Galaxy Discoveries from the KMTNet Supernova Program. II. The NGC 3585 Group and Its Dynamical State. / Park, Hong Soo; Moon, Dae Sik; Zaritsky, Dennis; Kim, Sang Chul; Lee, Youngdae; Cha, Sang Mok; Lee, Yongseok.

In: Astrophysical Journal, Vol. 885, No. 1, 88, 01.11.2019.

Research output: Contribution to journalArticle

Park, Hong Soo ; Moon, Dae Sik ; Zaritsky, Dennis ; Kim, Sang Chul ; Lee, Youngdae ; Cha, Sang Mok ; Lee, Yongseok. / Dwarf Galaxy Discoveries from the KMTNet Supernova Program. II. The NGC 3585 Group and Its Dynamical State. In: Astrophysical Journal. 2019 ; Vol. 885, No. 1.
@article{92583cf3e4dc4d5c845455b7900ed976,
title = "Dwarf Galaxy Discoveries from the KMTNet Supernova Program. II. The NGC 3585 Group and Its Dynamical State",
abstract = "We present our discovery and analysis of dwarf galaxies in the NGC 3585 galaxy group by the Korea Microlensing Telescope Network (KMTNet) Supernova Program. Using deep stack images reaching ≃28 mag arcsec-2 in BVI, we discovered 46 dwarf galaxy candidates distributed in a field of 7 square degrees. The dwarf galaxy candidates exhibit a central surface brightness as faint as μ 0,V = 26.2 mag arcsec-2, with effective radii larger than 150 pc and total absolute magnitudes brighter than M V ≈ -10 mag, if at the distance of NGC 3585. The dwarf galaxy surface number density decreases with projected distance from NGC 3585. We estimate the background contamination to be about 20{\%} based both on the number density profile and on diffuse galaxy counts in a control field. The dwarf galaxy colors and S{\'e}rsic structural parameters are consistent with those found for other dwarf galaxies. Unusually, there is no indication of a change in color or brightness in the dwarf galaxy candidates with projected distance from the group center. Approximately 20{\%} of the candidates contain an unresolved nucleus. The nucleated fraction is larger for brighter (and redder) galaxies, but is independent of distance from the group center. We identify four ultra-diffuse galaxy candidates, all near the group center. We interpret these spatial properties as suggesting that the NGC 3585 group might be dynamically younger than the typical group. The galaxy luminosity function of the NGC 3585 group has a faint-end slope of α ≈ -1.39, which is roughly consistent with the slopes found for other nearby groups. The possible dependence of the slope on global group properties is still unclear and continues to motivate our homogeneous deep survey of dozens of nearby groups.",
keywords = "galaxies: dwarf, galaxies: groups: individual (NGC 3585)",
author = "Park, {Hong Soo} and Moon, {Dae Sik} and Dennis Zaritsky and Kim, {Sang Chul} and Youngdae Lee and Cha, {Sang Mok} and Yongseok Lee",
year = "2019",
month = "11",
day = "1",
doi = "10.3847/1538-4357/ab4794",
language = "English (US)",
volume = "885",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",

}

TY - JOUR

T1 - Dwarf Galaxy Discoveries from the KMTNet Supernova Program. II. The NGC 3585 Group and Its Dynamical State

AU - Park, Hong Soo

AU - Moon, Dae Sik

AU - Zaritsky, Dennis

AU - Kim, Sang Chul

AU - Lee, Youngdae

AU - Cha, Sang Mok

AU - Lee, Yongseok

PY - 2019/11/1

Y1 - 2019/11/1

N2 - We present our discovery and analysis of dwarf galaxies in the NGC 3585 galaxy group by the Korea Microlensing Telescope Network (KMTNet) Supernova Program. Using deep stack images reaching ≃28 mag arcsec-2 in BVI, we discovered 46 dwarf galaxy candidates distributed in a field of 7 square degrees. The dwarf galaxy candidates exhibit a central surface brightness as faint as μ 0,V = 26.2 mag arcsec-2, with effective radii larger than 150 pc and total absolute magnitudes brighter than M V ≈ -10 mag, if at the distance of NGC 3585. The dwarf galaxy surface number density decreases with projected distance from NGC 3585. We estimate the background contamination to be about 20% based both on the number density profile and on diffuse galaxy counts in a control field. The dwarf galaxy colors and Sérsic structural parameters are consistent with those found for other dwarf galaxies. Unusually, there is no indication of a change in color or brightness in the dwarf galaxy candidates with projected distance from the group center. Approximately 20% of the candidates contain an unresolved nucleus. The nucleated fraction is larger for brighter (and redder) galaxies, but is independent of distance from the group center. We identify four ultra-diffuse galaxy candidates, all near the group center. We interpret these spatial properties as suggesting that the NGC 3585 group might be dynamically younger than the typical group. The galaxy luminosity function of the NGC 3585 group has a faint-end slope of α ≈ -1.39, which is roughly consistent with the slopes found for other nearby groups. The possible dependence of the slope on global group properties is still unclear and continues to motivate our homogeneous deep survey of dozens of nearby groups.

AB - We present our discovery and analysis of dwarf galaxies in the NGC 3585 galaxy group by the Korea Microlensing Telescope Network (KMTNet) Supernova Program. Using deep stack images reaching ≃28 mag arcsec-2 in BVI, we discovered 46 dwarf galaxy candidates distributed in a field of 7 square degrees. The dwarf galaxy candidates exhibit a central surface brightness as faint as μ 0,V = 26.2 mag arcsec-2, with effective radii larger than 150 pc and total absolute magnitudes brighter than M V ≈ -10 mag, if at the distance of NGC 3585. The dwarf galaxy surface number density decreases with projected distance from NGC 3585. We estimate the background contamination to be about 20% based both on the number density profile and on diffuse galaxy counts in a control field. The dwarf galaxy colors and Sérsic structural parameters are consistent with those found for other dwarf galaxies. Unusually, there is no indication of a change in color or brightness in the dwarf galaxy candidates with projected distance from the group center. Approximately 20% of the candidates contain an unresolved nucleus. The nucleated fraction is larger for brighter (and redder) galaxies, but is independent of distance from the group center. We identify four ultra-diffuse galaxy candidates, all near the group center. We interpret these spatial properties as suggesting that the NGC 3585 group might be dynamically younger than the typical group. The galaxy luminosity function of the NGC 3585 group has a faint-end slope of α ≈ -1.39, which is roughly consistent with the slopes found for other nearby groups. The possible dependence of the slope on global group properties is still unclear and continues to motivate our homogeneous deep survey of dozens of nearby groups.

KW - galaxies: dwarf

KW - galaxies: groups: individual (NGC 3585)

UR - http://www.scopus.com/inward/record.url?scp=85075245935&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85075245935&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/ab4794

DO - 10.3847/1538-4357/ab4794

M3 - Article

AN - SCOPUS:85075245935

VL - 885

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

M1 - 88

ER -