Multiwavelength Bulge–Disk Decomposition for the Galaxy M81 (NGC 3031). I. Morphology

A panchromatic investigation of morphology for the early-type spiral galaxy M81 is presented in this paper. We perform bulge–disk decomposition in M81 images at a total of 20 wave bands from far-UV to near-IR (NIR) obtained with GALEX, Swift, Sloan Digital Sky Survey, WIYN, Two Micron All Sky Survey...

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Main Authors: Jun-Yu Gong, Ye-Wei Mao, Hua Gao, Si-Yue Yu
Format: Article
Language:English
Published: IOP Publishing 2023-01-01
Series:The Astrophysical Journal Supplement Series
Subjects:
Online Access:https://doi.org/10.3847/1538-4365/acd554
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author Jun-Yu Gong
Ye-Wei Mao
Hua Gao
Si-Yue Yu
author_facet Jun-Yu Gong
Ye-Wei Mao
Hua Gao
Si-Yue Yu
author_sort Jun-Yu Gong
collection DOAJ
description A panchromatic investigation of morphology for the early-type spiral galaxy M81 is presented in this paper. We perform bulge–disk decomposition in M81 images at a total of 20 wave bands from far-UV to near-IR (NIR) obtained with GALEX, Swift, Sloan Digital Sky Survey, WIYN, Two Micron All Sky Survey, Wide-field Infrared Survey Explorer, and Spitzer. Morphological parameters such as Sérsic index, effective radius, position angle, and axis ratio for the bulge and the disk are thus derived at all of the wave bands, which enables quantifying the morphological K -correction for M81 and makes it possible to reproduce images for the bulge and the disk in the galaxy at any wave band. The morphology as a function of wavelength appears as a variable-slope trend of the Sérsic index and the effective radius, in which the variations are steep at UV–optical and shallow at optical–NIR bands; the position angle and the axis ratio keep invariable at least at optical–NIR bands. It is worth noting that the Sérsic index for the bulge reaches ∼4–5 at optical and NIR bands, but drops to ∼1 at UV bands. This difference brings forward a caveat that a classical bulge is likely misidentified for a pseudobulge or no bulge at high redshifts where galaxies are observed through rest-frame UV channels with optical telescopes. The next work of this series is planned to study spatially resolved spectral energy distributions for the bulge and the disk, respectively, and thereby explore stellar population properties and star formation/quenching history for the galaxy composed of the subsystems.
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spelling doaj.art-ea6084825bf345fc8a0cae4c313e0cfd2023-09-03T15:07:46ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492023-01-0126722610.3847/1538-4365/acd554Multiwavelength Bulge–Disk Decomposition for the Galaxy M81 (NGC 3031). I. MorphologyJun-Yu Gong0Ye-Wei Mao1https://orcid.org/0000-0002-7349-9784Hua Gao2https://orcid.org/0000-0003-1015-5367Si-Yue Yu3https://orcid.org/0000-0002-3462-4175Center for Astrophysics, Guangzhou University , Guangzhou 510006, People's Republic of China ; ywmao@gzhu.edu.cn; Department of Astronomy, School of Physics and Materials Science, Guangzhou University , Guangzhou 510006, People's Republic of ChinaCenter for Astrophysics, Guangzhou University , Guangzhou 510006, People's Republic of China ; ywmao@gzhu.edu.cn; Department of Astronomy, School of Physics and Materials Science, Guangzhou University , Guangzhou 510006, People's Republic of ChinaInstitute for Astronomy, University of Hawaii , 2680 Woodlawn Drive, Honolulu, HI 96822, USA; Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study , The University of Tokyo, Kashiwa, Chiba 277-8583, JapanMax-Planck-Institut für Radioastronomie , Auf dem Hügel 69, D-53121 Bonn, GermanyA panchromatic investigation of morphology for the early-type spiral galaxy M81 is presented in this paper. We perform bulge–disk decomposition in M81 images at a total of 20 wave bands from far-UV to near-IR (NIR) obtained with GALEX, Swift, Sloan Digital Sky Survey, WIYN, Two Micron All Sky Survey, Wide-field Infrared Survey Explorer, and Spitzer. Morphological parameters such as Sérsic index, effective radius, position angle, and axis ratio for the bulge and the disk are thus derived at all of the wave bands, which enables quantifying the morphological K -correction for M81 and makes it possible to reproduce images for the bulge and the disk in the galaxy at any wave band. The morphology as a function of wavelength appears as a variable-slope trend of the Sérsic index and the effective radius, in which the variations are steep at UV–optical and shallow at optical–NIR bands; the position angle and the axis ratio keep invariable at least at optical–NIR bands. It is worth noting that the Sérsic index for the bulge reaches ∼4–5 at optical and NIR bands, but drops to ∼1 at UV bands. This difference brings forward a caveat that a classical bulge is likely misidentified for a pseudobulge or no bulge at high redshifts where galaxies are observed through rest-frame UV channels with optical telescopes. The next work of this series is planned to study spatially resolved spectral energy distributions for the bulge and the disk, respectively, and thereby explore stellar population properties and star formation/quenching history for the galaxy composed of the subsystems.https://doi.org/10.3847/1538-4365/acd554Extragalactic astronomyGalaxy photometryGalaxiesGalaxy structure
spellingShingle Jun-Yu Gong
Ye-Wei Mao
Hua Gao
Si-Yue Yu
Multiwavelength Bulge–Disk Decomposition for the Galaxy M81 (NGC 3031). I. Morphology
The Astrophysical Journal Supplement Series
Extragalactic astronomy
Galaxy photometry
Galaxies
Galaxy structure
title Multiwavelength Bulge–Disk Decomposition for the Galaxy M81 (NGC 3031). I. Morphology
title_full Multiwavelength Bulge–Disk Decomposition for the Galaxy M81 (NGC 3031). I. Morphology
title_fullStr Multiwavelength Bulge–Disk Decomposition for the Galaxy M81 (NGC 3031). I. Morphology
title_full_unstemmed Multiwavelength Bulge–Disk Decomposition for the Galaxy M81 (NGC 3031). I. Morphology
title_short Multiwavelength Bulge–Disk Decomposition for the Galaxy M81 (NGC 3031). I. Morphology
title_sort multiwavelength bulge disk decomposition for the galaxy m81 ngc 3031 i morphology
topic Extragalactic astronomy
Galaxy photometry
Galaxies
Galaxy structure
url https://doi.org/10.3847/1538-4365/acd554
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