SDSS-IV MaNGA: Stellar M/L gradients and the M/L-colour relation in galaxies
<p>The stellar mass-to-light ratio gradient in SDSS <em>r</em>-band ∇(<em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub>) of a galaxy depends on its mass assembly history, which is imprinted in its m...
| প্রধান লেখক: | , , , , , |
|---|---|
| বিন্যাস: | Journal article |
| ভাষা: | English |
| প্রকাশিত: |
Oxford University Press
2021
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| _version_ | 1826290493791666176 |
|---|---|
| author | Ge, J Mao, S Lu, Y Cappellari, M Long, RJ Yan, R |
| author_facet | Ge, J Mao, S Lu, Y Cappellari, M Long, RJ Yan, R |
| author_sort | Ge, J |
| collection | OXFORD |
| description | <p>The stellar mass-to-light ratio gradient in SDSS <em>r</em>-band ∇(<em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub>) of a galaxy depends on its mass assembly history, which is imprinted in its morphology and gradients of age, metallicity, and stellar initial mass function (IMF). Taking a MaNGA sample of 2051 galaxies with stellar masses ranging from 10<sup>9</sup> to 10<sup>12</sup><em>M</em><sub>⊙</sub> released in SDSS DR15, we focus on face-on galaxies, without merger and bar signatures, and investigate the dependence of the 2D ∇(<em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub>) on other galaxy properties, including <em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub>-colour relationships by assuming a fixed Salpeter IMF as the mass normalization reference. The median gradient is ∇<em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub> ∼ −0.1 (i.e. the <em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub> is larger at the centre) for massive galaxies, becomes flat around <em>M</em><sub>*</sub> ∼ 10<sup>10</sup><em>M</em><sub>⊙</sub> and change sign to ∇<em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub> ∼ 0.1 at the lowest masses. The <em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub> inside a half-light radius increases with increasing galaxy stellar mass; in each mass bin, early-type galaxies have the highest value, while pure-disc late-type galaxies have the smallest. Correlation analyses suggest that the mass-weighted stellar age is the dominant parameter influencing the <em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub> profile, since a luminosity-weighted age is easily affected by star formation when the specific star formation rate (sSFR) inside the half-light radius is higher than 10<sup>−3</sup> Gyr<sup>−1</sup>. With increased sSFR gradient, one can obtain a steeper negative ∇(<em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub>). The scatter in the slopes of <em>M</em><sub>*</sub>/<em>L</em>-colour relations increases with increasing sSFR, for example, the slope for post-starburst galaxies can be flattened to 0.45 from the global value 0.87 in the <em>M</em><sub>*</sub>/<em>L</em> versus <em>g</em> − <em>r</em> diagram. Hence converting galaxy colours to <em>M</em><sub>*</sub>/<em>L</em> should be done carefully, especially for those galaxies with young luminosity-weighted stellar ages, which can have quite different star formation histories.</p> |
| first_indexed | 2024-03-07T02:45:02Z |
| format | Journal article |
| id | oxford-uuid:abc2a237-ae94-4997-8a2d-689bbec56521 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T02:45:02Z |
| publishDate | 2021 |
| publisher | Oxford University Press |
| record_format | dspace |
| spelling | oxford-uuid:abc2a237-ae94-4997-8a2d-689bbec565212022-03-27T03:24:10ZSDSS-IV MaNGA: Stellar M/L gradients and the M/L-colour relation in galaxiesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:abc2a237-ae94-4997-8a2d-689bbec56521EnglishSymplectic ElementsOxford University Press2021Ge, JMao, SLu, YCappellari, MLong, RJYan, R<p>The stellar mass-to-light ratio gradient in SDSS <em>r</em>-band ∇(<em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub>) of a galaxy depends on its mass assembly history, which is imprinted in its morphology and gradients of age, metallicity, and stellar initial mass function (IMF). Taking a MaNGA sample of 2051 galaxies with stellar masses ranging from 10<sup>9</sup> to 10<sup>12</sup><em>M</em><sub>⊙</sub> released in SDSS DR15, we focus on face-on galaxies, without merger and bar signatures, and investigate the dependence of the 2D ∇(<em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub>) on other galaxy properties, including <em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub>-colour relationships by assuming a fixed Salpeter IMF as the mass normalization reference. The median gradient is ∇<em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub> ∼ −0.1 (i.e. the <em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub> is larger at the centre) for massive galaxies, becomes flat around <em>M</em><sub>*</sub> ∼ 10<sup>10</sup><em>M</em><sub>⊙</sub> and change sign to ∇<em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub> ∼ 0.1 at the lowest masses. The <em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub> inside a half-light radius increases with increasing galaxy stellar mass; in each mass bin, early-type galaxies have the highest value, while pure-disc late-type galaxies have the smallest. Correlation analyses suggest that the mass-weighted stellar age is the dominant parameter influencing the <em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub> profile, since a luminosity-weighted age is easily affected by star formation when the specific star formation rate (sSFR) inside the half-light radius is higher than 10<sup>−3</sup> Gyr<sup>−1</sup>. With increased sSFR gradient, one can obtain a steeper negative ∇(<em>M</em><sub>*</sub>/<em>L</em><sub><em>r</em></sub>). The scatter in the slopes of <em>M</em><sub>*</sub>/<em>L</em>-colour relations increases with increasing sSFR, for example, the slope for post-starburst galaxies can be flattened to 0.45 from the global value 0.87 in the <em>M</em><sub>*</sub>/<em>L</em> versus <em>g</em> − <em>r</em> diagram. Hence converting galaxy colours to <em>M</em><sub>*</sub>/<em>L</em> should be done carefully, especially for those galaxies with young luminosity-weighted stellar ages, which can have quite different star formation histories.</p> |
| spellingShingle | Ge, J Mao, S Lu, Y Cappellari, M Long, RJ Yan, R SDSS-IV MaNGA: Stellar M/L gradients and the M/L-colour relation in galaxies |
| title | SDSS-IV MaNGA: Stellar M/L gradients and the M/L-colour relation in galaxies |
| title_full | SDSS-IV MaNGA: Stellar M/L gradients and the M/L-colour relation in galaxies |
| title_fullStr | SDSS-IV MaNGA: Stellar M/L gradients and the M/L-colour relation in galaxies |
| title_full_unstemmed | SDSS-IV MaNGA: Stellar M/L gradients and the M/L-colour relation in galaxies |
| title_short | SDSS-IV MaNGA: Stellar M/L gradients and the M/L-colour relation in galaxies |
| title_sort | sdss iv manga stellar m l gradients and the m l colour relation in galaxies |
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