LITTLE THINGS in 3D: Robust determination of the circular velocity of dwarf irregular galaxies

G. Iorio; F. Fraternali; C. Nipoti; E. Di Teodoro; J. I. Read; G. Battaglia

doi:10.1093/mnras/stw3285

LITTLE THINGS in 3D: Robust determination of the circular velocity of dwarf irregular galaxies

G. Iorio^*, F. Fraternali, C. Nipoti, E. Di Teodoro, J. I. Read, G. Battaglia

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

102 Citations (Scopus)

Abstract

Dwarf irregular galaxies (dIrrs) are the smallest stellar systems with extended HI discs. The study of the kinematics of such discs is a powerful tool to estimate the total matter distribution at these very small scales. In this work, we study the HI kinematics of 17 galaxies extracted from the 'Local Irregulars That Trace Luminosity Extremes, The HI Nearby Galaxy Survey' (LITTLE THINGS). Our approach differs significantly from previous studies in that we directly fit 3D models (two spatial dimensions plus one spectral dimension) using the software ^3DBAROLO, fully exploiting the information in the HI data cubes. For each galaxy, we derive the geometric parameters of the HI disc (inclination and position angle), the radial distribution of the surface density, the velocity-dispersion (s_v) profile and the rotation curve. The circular velocity (V_c), which traces directly the galactic potential, is then obtained by correcting the rotation curve for the asymmetric drift. As an initial application, we show that these dIrrs lie on a baryonic Tully-Fisher relation in excellent agreement with that seen on larger scales. The final products of this work are high-quality, ready-to-use kinematic data (V_c and s_v) that we make publicly available. These can be used to perform dynamical studies and improve our understanding of these low-mass galaxies.

Original language	English
Pages (from-to)	4159-4192
Number of pages	34
Journal	Monthly Notices of the Royal Astronomical Society
Volume	466
Issue number	4
DOIs	https://doi.org/10.1093/mnras/stw3285
Publication status	Published - 2017

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title = "LITTLE THINGS in 3D: Robust determination of the circular velocity of dwarf irregular galaxies",

abstract = "Dwarf irregular galaxies (dIrrs) are the smallest stellar systems with extended HI discs. The study of the kinematics of such discs is a powerful tool to estimate the total matter distribution at these very small scales. In this work, we study the HI kinematics of 17 galaxies extracted from the 'Local Irregulars That Trace Luminosity Extremes, The HI Nearby Galaxy Survey' (LITTLE THINGS). Our approach differs significantly from previous studies in that we directly fit 3D models (two spatial dimensions plus one spectral dimension) using the software 3DBAROLO, fully exploiting the information in the HI data cubes. For each galaxy, we derive the geometric parameters of the HI disc (inclination and position angle), the radial distribution of the surface density, the velocity-dispersion (sv) profile and the rotation curve. The circular velocity (Vc), which traces directly the galactic potential, is then obtained by correcting the rotation curve for the asymmetric drift. As an initial application, we show that these dIrrs lie on a baryonic Tully-Fisher relation in excellent agreement with that seen on larger scales. The final products of this work are high-quality, ready-to-use kinematic data (Vc and sv) that we make publicly available. These can be used to perform dynamical studies and improve our understanding of these low-mass galaxies.",

keywords = "Galaxies: ISM, Galaxies: dwarf, Galaxies: kinematics and dynamics, Galaxies: structure",

author = "G. Iorio and F. Fraternali and C. Nipoti and {Di Teodoro}, E. and Read, {J. I.} and G. Battaglia",

note = "Publisher Copyright: {\textcopyright} 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.",

year = "2017",

doi = "10.1093/mnras/stw3285",

language = "English",

volume = "466",

pages = "4159--4192",

journal = "Monthly Notices of the Royal Astronomical Society",

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publisher = "Oxford University Press ",

number = "4",

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TY - JOUR

T1 - LITTLE THINGS in 3D

T2 - Robust determination of the circular velocity of dwarf irregular galaxies

AU - Iorio, G.

AU - Fraternali, F.

AU - Nipoti, C.

AU - Di Teodoro, E.

AU - Read, J. I.

AU - Battaglia, G.

PY - 2017

Y1 - 2017

N2 - Dwarf irregular galaxies (dIrrs) are the smallest stellar systems with extended HI discs. The study of the kinematics of such discs is a powerful tool to estimate the total matter distribution at these very small scales. In this work, we study the HI kinematics of 17 galaxies extracted from the 'Local Irregulars That Trace Luminosity Extremes, The HI Nearby Galaxy Survey' (LITTLE THINGS). Our approach differs significantly from previous studies in that we directly fit 3D models (two spatial dimensions plus one spectral dimension) using the software 3DBAROLO, fully exploiting the information in the HI data cubes. For each galaxy, we derive the geometric parameters of the HI disc (inclination and position angle), the radial distribution of the surface density, the velocity-dispersion (sv) profile and the rotation curve. The circular velocity (Vc), which traces directly the galactic potential, is then obtained by correcting the rotation curve for the asymmetric drift. As an initial application, we show that these dIrrs lie on a baryonic Tully-Fisher relation in excellent agreement with that seen on larger scales. The final products of this work are high-quality, ready-to-use kinematic data (Vc and sv) that we make publicly available. These can be used to perform dynamical studies and improve our understanding of these low-mass galaxies.

AB - Dwarf irregular galaxies (dIrrs) are the smallest stellar systems with extended HI discs. The study of the kinematics of such discs is a powerful tool to estimate the total matter distribution at these very small scales. In this work, we study the HI kinematics of 17 galaxies extracted from the 'Local Irregulars That Trace Luminosity Extremes, The HI Nearby Galaxy Survey' (LITTLE THINGS). Our approach differs significantly from previous studies in that we directly fit 3D models (two spatial dimensions plus one spectral dimension) using the software 3DBAROLO, fully exploiting the information in the HI data cubes. For each galaxy, we derive the geometric parameters of the HI disc (inclination and position angle), the radial distribution of the surface density, the velocity-dispersion (sv) profile and the rotation curve. The circular velocity (Vc), which traces directly the galactic potential, is then obtained by correcting the rotation curve for the asymmetric drift. As an initial application, we show that these dIrrs lie on a baryonic Tully-Fisher relation in excellent agreement with that seen on larger scales. The final products of this work are high-quality, ready-to-use kinematic data (Vc and sv) that we make publicly available. These can be used to perform dynamical studies and improve our understanding of these low-mass galaxies.

KW - Galaxies: ISM

KW - Galaxies: dwarf

KW - Galaxies: kinematics and dynamics

KW - Galaxies: structure

UR - http://www.scopus.com/inward/record.url?scp=85014914334&partnerID=8YFLogxK

U2 - 10.1093/mnras/stw3285

DO - 10.1093/mnras/stw3285

M3 - Article

SN - 0035-8711

VL - 466

SP - 4159

EP - 4192

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 4

ER -

LITTLE THINGS in 3D: Robust determination of the circular velocity of dwarf irregular galaxies

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