Correlations of gas, dust and young stellar populations in the spiral galaxy NGC 7331

Year 2022, Volume: 24 Issue: 1, 138 - 151, 05.01.2022

Selçuk Topal

https://doi.org/10.25092/baunfbed.948997

Abstract

Molecular clouds (MCs) in galaxies are complex places with many phases. It is, therefore, essential to study the physics and kinematics of the MCs using multiple emission lines. We probe the physics of the molecular gas and dust in the nearby spiral galaxy NGC 7331 using multiple emission lines, i.e. carbon monoxide (CO), 24μm and far-ultraviolet (FUV) data. 14 positions were targeted across the gaseous disc of NGC 7331. We found that CO intensities, gas mass, gas surface density, and 24μm-to-FUV flux ratio (i.e. the extinction) increase up to about 40 arcsec from the centre and then start to decrease. There is a positive correlation between most of the pair of parameters studied (except FUV flux density). The beam-averaged physical parameters on the eastern side of the disc show higher median values than those on the western side. Our results indicate that the star formation activity, stellar populations and overall physical properties of the ISM are different on either side of the disc. Our study provides notable insights into the complex nature of the interstellar medium (ISM) in galaxies and has the potential to provoke future higher-resolution studies yet to come.

Keywords

Galaxies, spiral galaxies, molecular gas, far-ultraviolet emission, 24µm emission

NGC 7331 sarmal gökadasında gaz, toz ve genç yıldız popülasyonları arasındaki korelasyon

Abstract

Galaksilerdeki moleküler bulutlar (MC'ler), birçok evresi olan karmaşık yerlerdir. Bu nedenle, çoklu emisyon çizgileri kullanarak MC'lerin fiziğini ve kinematiğini incelemek önemlidir. Çok sayıda emisyon verisi kullanarak, şöyle ki karbon monoksit (CO), 24micron ve uzak ultraviyole (FUV) verileri, yakın evrende yer alan sarmal galaksi NGC 7331'deki moleküler gaz ve tozun fiziğini araştırıyoruz. NGC 7331 galaksisinin gazlı diski boyunca 14 konum hedeflendi. CO yoğunluklarının, gaz kütlesinin, gaz yüzey yoğunluğunun ve 24micron / FUV akı oranının (yani sönümleme) merkezden yaklaşık 40 yay saniyeye kadar arttığını ve sonra azalmaya başladığını bulduk. Çalışılan parametre çiftlerinin çoğu arasında pozitif bir korelasyon vardır (FUV akı yoğunluğu hariç). Diskin doğu tarafında elde edilen fiziksel parametreler batı tarafındakilerden daha yüksek medyan değerleri göstermektedir. Sonuçlar, yıldız oluşum aktivitesinin, yıldız popülasyonlarının ve ISM’in genel fiziksel özelliklerinin diskin her iki tarafında farklı olduğunu göstermektedir. Çalışmamız, galaksilerdeki ISM'in karmaşık doğası hakkında dikkate değer bilgiler sağlamakta ve gelecekte yapılması planlanan daha yüksek çözünürlüklü çalışmaları teşvik etmek potansiyeline sahiptir.

Keywords

Gökadalar, sarmal gökadalar, moleküler gaz, uzak morötesi salma, 24 µm salma

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