Doctoral theses
Current Record: 21 of 171
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Identifier |
000437567 |
Title |
Measuring star-formation rates in galaxies and their correlation with X-ray emission |
Alternative Title |
Μέθοδοι μέτρησης του ρυθμού αστρογένεσης γαλαξιών και η συσχέτισή τους με την ακτινοβολία ακτίνω X |
Author
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Κουρουμπατζάκης, Κωνσταντίνος
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Thesis advisor
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Ζέζας, Ανδρέας
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Reviewer
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Χαρμανδάρης, Βασίλης
Παυλίδου, Βασιλική
Παπαδάκης, Ιωσήφ
Reig. Pablo
Diaz Santos. Tanio
Ξυλούρης, Μανόλης
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Abstract |
We present a study of different star-formation rate (SFR) indicators, focusing on Hα emission, and its comparison with other SFR tracers. We present Hα
photometry and provide calibrations of Hα-based SFRs for the Star-Formation
Reference Survey (SFRS), a representative sample of star-forming galaxies in
the local Universe. We explore the effect of extinction correction based on
the Balmer decrement, infrared excess (IRX), and fits of spectral energy distributions (SEDs), as well as, corrections for the contribution of the [NII] lines
emission. We provide a functional description between extinction and metallicity.
For a subset of the SFRS sample with good quality X-ray data, we explore
the connection between SFR and X-ray luminosity (LX) in sub-galactic scales. There is good agreement with established LX–SFR relations down to SFR≃10-3 M☉yr-1, below which an excess in X-ray luminosity emerges which likely
arises from low-mass X-ray binaries. The SFR derived from Hα shows the
tightest correlation with X-ray luminosity because Hα emission probes stellar
populations with ages similar to HMXB formation timescales.
In order to explore the effect of metallicity on the X-ray luminosity–SFR
relation, we present a systematic study of the metallicity variations within the
collisional ring galaxy NGC 922, based on long-slit spectroscopic, X-ray, and IR
observations. We find a metallicity difference between star-forming regions in
the bulge and the ring, with metallicities ranging from almost solar to significantly sub-solar ([12 + log(O/H)]≃8.2). We find an anti-correlation between
the X-ray luminosity and metallicity of the sub-galactic regions of NGC 922.
The different regions have similar stellar population ages leaving metallicity as
the main driver of the anti-correlation.
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Language |
English |
Subject |
Galaxies |
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Star formation |
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X-Ray binaries |
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Αστρογένεση |
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Γαλαξίες |
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Δυαδικά συστήματα ακτίνων X |
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Θόρυβος σπιν |
Issue date |
2021-03-10 |
Collection
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School/Department--School of Sciences and Engineering--Department of Physics--Doctoral theses
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Type of Work--Doctoral theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/d/8/e/metadata-dlib-1613391776-250117-23746.tkl
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Views |
734 |