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Title: Dark matter and H i in ultra-diffuse galaxy UGC 2162

Abstract

ABSTRACT Our GMRT (Giant Metrewave Radio Telescope) H i observations of the ultra-diffuse galaxy (UDG) UGC 2162, projected ∼ 300 kpc from the centre of the M 77 group, reveal it to a have an extended H i disc ($$R_{\rm H\,{\small I}}/R_{25}$$ ∼ 3.3) with a moderate rotational velocity (Vrot ∼ 31 km s−1). This Vrotis in line with that of dwarf galaxies with similar H i mass. We estimate an Mdyn of ∼1.14 × 109 M⊙ within the galaxy’s $$R_ \rm {H\,{\small I}}$$ ∼ 5.2 kpc. Additionally, our estimates of M200 for the galaxy from NFW models are in the range of 5.0–8.8 × 1010 M⊙. Comparing UGC 2162 to samples of UDGs with H i detections show it to have amongst the smallest Re with its MH i/M* being distinctly higher and g – icolour slightly bluer than typical values in those samples. We also compared H i and dark matter (DM) halo properties of UGC 2162 with dwarf galaxies in the LITTLE THINGS sample and find its DM halo mass and profile are within the range expected for a dwarf galaxy. While we were unable to determine the origin of the galaxy’s present-day optical form from our study, its normal H i rotation velocity in relation to its H i mass, H i morphology, environment, and dwarf mass DM halo ruled out some of the proposed ultra-diffuse galaxy formation scenarios for this galaxy.

Authors:
ORCiD logo [1]; ORCiD logo [2];  [3];  [4]
  1. Purple Mountain Observatory, No. 8 Yuanhua Road, Qixia District, Nanjing 210034, China
  2. Institute of Astrophysics and Space Sciences (IA), Rua das Estrelas, 4150-762 Porto, Portugal
  3. Department of Astronomy, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
  4. International Centre for Radio Astronomy Research (ICRAR), University of Western Australia, 35 Stirling Highway, WA 6009, Australia
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1568890
Resource Type:
Published Article
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
Journal Name: Monthly Notices of the Royal Astronomical Society Journal Volume: 488 Journal Issue: 3; Journal ID: ISSN 0035-8711
Publisher:
Oxford University Press
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Sengupta, Chandreyee, Scott, T. C., Chung, Aeree, and Wong, O. Ivy. Dark matter and H i in ultra-diffuse galaxy UGC 2162. United Kingdom: N. p., 2019. Web. doi:10.1093/mnras/stz1884.
Sengupta, Chandreyee, Scott, T. C., Chung, Aeree, & Wong, O. Ivy. Dark matter and H i in ultra-diffuse galaxy UGC 2162. United Kingdom. doi:10.1093/mnras/stz1884.
Sengupta, Chandreyee, Scott, T. C., Chung, Aeree, and Wong, O. Ivy. Wed . "Dark matter and H i in ultra-diffuse galaxy UGC 2162". United Kingdom. doi:10.1093/mnras/stz1884.
@article{osti_1568890,
title = {Dark matter and H i in ultra-diffuse galaxy UGC 2162},
author = {Sengupta, Chandreyee and Scott, T. C. and Chung, Aeree and Wong, O. Ivy},
abstractNote = {ABSTRACT Our GMRT (Giant Metrewave Radio Telescope) H i observations of the ultra-diffuse galaxy (UDG) UGC 2162, projected ∼ 300 kpc from the centre of the M 77 group, reveal it to a have an extended H i disc ($R_{\rm H\,{\small I}}/R_{25}$ ∼ 3.3) with a moderate rotational velocity (Vrot ∼ 31 km s−1). This Vrotis in line with that of dwarf galaxies with similar H i mass. We estimate an Mdyn of ∼1.14 × 109 M⊙ within the galaxy’s $R_ \rm {H\,{\small I}}$ ∼ 5.2 kpc. Additionally, our estimates of M200 for the galaxy from NFW models are in the range of 5.0–8.8 × 1010 M⊙. Comparing UGC 2162 to samples of UDGs with H i detections show it to have amongst the smallest Re with its MH i/M* being distinctly higher and g – icolour slightly bluer than typical values in those samples. We also compared H i and dark matter (DM) halo properties of UGC 2162 with dwarf galaxies in the LITTLE THINGS sample and find its DM halo mass and profile are within the range expected for a dwarf galaxy. While we were unable to determine the origin of the galaxy’s present-day optical form from our study, its normal H i rotation velocity in relation to its H i mass, H i morphology, environment, and dwarf mass DM halo ruled out some of the proposed ultra-diffuse galaxy formation scenarios for this galaxy.},
doi = {10.1093/mnras/stz1884},
journal = {Monthly Notices of the Royal Astronomical Society},
number = 3,
volume = 488,
place = {United Kingdom},
year = {2019},
month = {7}
}

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