The Intrinsic Shape of Galaxy Bulges

Méndez-Abreu, J.

doi:10.1007/978-3-319-19378-6_2

Cited by 7 publications

(1 citation statement)

References 140 publications

(210 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…11). The mean is 0.4, which is in agreement with spheroidal galaxies viewed from random line of sights (Padilla & Strauss 2008;Méndez-Abreu 2016). Figure 19 shows the SFR-stellar mass relation for our sample galaxies, as well as that of individual star-forming knots.…”

Section: Single-knot Galaxiessupporting

confidence: 74%

Starburst galaxies in the COSMOS field: clumpy star-formation at redshift 0 <z< 0.5

Hinojosa-Goñi

Muñoz–Tuñón

Méndez-Abreu

2016

A&A

View full text Add to dashboard Cite

Context. At high redshift, starburst galaxies present irregular morphologies with 10−20% of their star formation occurring in giant clumps. These clumpy galaxies are considered the progenitors of local disk galaxies. To understand the properties of starbursts at intermediate and low redshift, it is fundamental to track their evolution and the possible link with the systems at higher z. Aims. We present an extensive, systematic, and multiband search and analysis of the starburst galaxies at redshift (0 < z < 0.5) in the COSMOS field, as well as detailed characteristics of their star-forming clumps by using Hubble Space Telescope/Advance Camera for Surveys (HST/ACS) images. Methods. The starburst galaxies are identified using a tailor-made intermediate-band color excess selection, tracing the simultaneous presence of Hα and [OIII] emission lines in the galaxies. Our methodology uses previous information from the zCOSMOS spectral database to calibrate the color excess as a function of the equivalent width of both spectral lines. This technique allows us to identify 220 starburst galaxies at redshift 0 < z < 0.5 using the SUBARU intermediate-band filters. Combining the high spatial resolution images from the HST/ACS with ground-based multi-wavelength photometry, we identify and parametrize the star-forming clumps in every galaxy. Their principal properties, sizes, masses, and star formation rates are provided. Results. The mass distribution of the starburst galaxies is remarkably similar to that of the whole galaxy sample with a peak around M/M ∼ 2 × 10 8 and only a few galaxies with M/M > 10 10 . We classify galaxies into three main types, depending on their HST morphology: single knot (Sknot), single star-forming knot plus diffuse light (Sknot+diffuse), and multiple star-forming knots (Mknots/clumpy) galaxy. We found a fraction of Mknots/clumpy galaxy f clumpy = 0.24 considering out total sample of starburst galaxies up to z ∼ 0.5. The individual star-forming knots in our sample follows the same L(Hα) vs. size scaling relation as local giant HII regions. However, they slightly differ from the one provided using samples at high redshift. This result highlights the importance of spatially resolving the star-forming regions for this kind of study. Star-forming clumps in the central regions of Mknots galaxies are more massive, and present higher star formation rates, than those in the outskirts. This trend is less clear when we consider either the mass surface density or surface star formation rate. Sknot galaxies do show properties similar to both dwarf elliptical and irregulars in the surface brightness (µ) versus M host diagram in the B-band, and to spheroidals and ellipticals in the µ versus M host diagram in the V-band. Conclusions. The properties of our star-forming knots in Sknot+diffuse and Mknots/clumpy galaxies support the predictions of recent numerical simulations claiming that they have been produced by violent disk instabilities. We suggest that the evolution of these knots means that large and m...

show abstract

Section: Single-knot Galaxiessupporting

confidence: 74%

Starburst galaxies in the COSMOS field: clumpy star-formation at redshift 0 <z< 0.5

Hinojosa-Goñi

Muñoz–Tuñón

Méndez-Abreu

2016

A&A

View full text Add to dashboard Cite

show abstract

Galactic shape and age go hand in hand

Weijmans

2018

Nat Astron

View full text Add to dashboard Cite

Barlenses and X-shaped features compared: two manifestations of boxy/peanut bulges

Laurikainen

Salo

2017

A&A

View full text Add to dashboard Cite

Context. Morphological characteristics of Boxy/Peanut bulges are studied, in particular whether most of the flux associated to bulges in galaxies with masses similar to those of the Milky Way at redshift z∼0, could belong to vertically thick inner part of the bar, in a similar manner as in the Milky Way itself. At high galaxy inclinations such structures manifest as Boxy/Peanut/X-shape features, and near to face-on view as barlenses. We also study the possibility that bulges in some fraction of unbarred galaxies could form in a similar manner as the bulges in barred galaxies. Aims. We use the Spitzer Survey of Stellar Structure in Galaxies (S 4 G) and the Near-IR S0 galaxy Survey (NIRS0S), to compile complete samples of galaxies with barlenses (N = 85), and X-shape features (N = 88). A sample of unbarred galaxies (N = 41) is also selected, based on similarity in their surface brightness profiles with those of barlens galaxies. Sizes and minor-to-major axis ratios (b/a) of these presumably vertically thick inner bar components are compared, and interpreted by means of synthetic images using N-body simulation models. Barlenses and their parent galaxies are divided into different sub-groups. Their possible parent galaxy counterparts in galaxies where the barlenses are manifested as X-shape features, are also identified. Methods. Unsharp mask images are created for all 214 sample galaxies. These images are used to recognize the X-shape features, and to measure their linear sizes, both along and perpendicular to the bar. For detecting possible boxy isophotes (using B 4 -parameter), isophotal analysis is also performed for the barlens galaxies. In the interpretation N-body simulations from are used: the models, exhibiting Boxy/Peanut/X/barlens morphologies, are viewed from isotropically chosen directions, covering the full range of galaxy inclinations in the sky. The created synthetic images are analyzed in a similar manner as the observations. Results. This is the first time that the observed properties of barlenses and X-shape features are directly compared, over a large range of galaxy inclinations. A comparison with the simulation models shows that the differences in their apparent sizes , a/r bar 0.5 for barlenses and a/r bar 0.5 for X-shapes, can be explained by projection effects. Observations at various inclinations are consistent with intrinsic a bl ≈ a X ≈ 0.5 r bar : here intrinsic size means the face-on semimajor axis length for bars and barlenses, and the semilength of X-shape when the bar is viewed exactly edge on. While X-shapes are quite common at intermediate galaxy inclinations (for i = 40 • -60 • their frequency is ∼ half of barlenses), they are seldom observed at smaller inclinations. This is consistent with our simulation models which have a small compact classical bulge producing a steep inner rotation slope, whereas bulgeless shallow rotation curve models predict that X-shapes should be visible even in face-on geometry. The steep rotation curve models are also consistent with the observed trend ...

show abstract

The Intrinsic Shape of Galaxy Bulges

Cited by 7 publications

References 140 publications

Starburst galaxies in the COSMOS field: clumpy star-formation at redshift 0 <z< 0.5

Starburst galaxies in the COSMOS field: clumpy star-formation at redshift 0 <z< 0.5

Galactic shape and age go hand in hand

Barlenses and X-shaped features compared: two manifestations of boxy/peanut bulges

Contact Info

Product

Resources

About