scholarly journals Characterizing the radial oxygen abundance distribution in disk galaxies

2019 ◽  
Vol 623 ◽  
pp. A7 ◽  
Author(s):  
I. A. Zinchenko ◽  
A. Just ◽  
L. S. Pilyugin ◽  
M. A. Lara-Lopez
Keyword(s):  
Surface Brightness ◽  
Disk Galaxies ◽  
Abundance Distribution ◽  
Oxygen Abundance ◽  
Abundance Gradient ◽  
Central Surface ◽  
The Galaxy ◽  
Axisymmetric Structures ◽  
Local Oxygen ◽  
Optical Radius

Context. The relation between the radial oxygen abundance distribution (gradient) and other parameters of a galaxy such as mass, Hubble type, and a bar strength, remains unclear although a large amount of observational data have been obtained in the past years. Aims. We examine the possible dependence of the radial oxygen abundance distribution on non-axisymmetrical structures (bar/spirals) and other macroscopic parameters such as the mass, the optical radius R25, the color g − r, and the surface brightness of the galaxy. A sample of disk galaxies from the third data release of the Calar Alto Legacy Integral Field Area Survey (CALIFA DR3) is considered. Methods. We adopted the Fourier amplitude A2 of the surface brightness as a quantitative characteristic of the strength of non-axisymmetric structures in a galactic disk, in addition to the commonly used morphologic division for A, AB, and B types based on the Hubble classification. To distinguish changes in local oxygen abundance caused by the non-axisymmetrical structures, the multiparametric mass–metallicity relation was constructed as a function of parameters such as the bar/spiral pattern strength, the disk size, color index g − r in the Sloan Digital Sky Survey (SDSS) bands, and central surface brightness of the disk. The gas-phase oxygen abundance gradient is determined by using the R calibration. Results. We find that there is no significant impact of the non-axisymmetric structures such as a bar and/or spiral patterns on the local oxygen abundance and radial oxygen abundance gradient of disk galaxies. Galaxies with higher mass, however, exhibit flatter oxygen abundance gradients in units of dex/kpc, but this effect is significantly less prominent for the oxygen abundance gradients in units of dex/R25 and almost disappears when the inner parts are avoided (R >  0.25R25). We show that the oxygen abundance in the central part of the galaxy depends neither on the optical radius R25 nor on the color g − r or the surface brightness of the galaxy. Instead, outside the central part of the galaxy, the oxygen abundance increases with g − r value and central surface brightness of the disk.

scholarly journals Relations between abundance characteristics and rotation velocity for star-forming MaNGA galaxies

2019 ◽  
Vol 623 ◽  
pp. A122 ◽  
Author(s):  
L. S. Pilyugin ◽  
E. K. Grebel ◽  
I. A. Zinchenko ◽  
Y. A. Nefedyev ◽  
J. M. Vílchez
Keyword(s):  
Rotation Velocity ◽  
Effective Radius ◽  
Oxygen Abundance ◽  
Abundance Gradient ◽  
Star Forming ◽  
The Galaxy ◽  
Basic Parameters ◽  
Central Oxygen ◽  
The Mean ◽  
Optical Radius

We derive rotation curves, surface brightness profiles, and oxygen abundance distributions for 147 late-type galaxies using the publicly available spectroscopy obtained by the MaNGA survey. Changes of the central oxygen abundance (O/H)0, the abundance at the optical radius (O/H)R25, and the abundance gradient with rotation velocity Vrot were examined for galaxies with rotation velocities from 90 km s−1 to 350 km s−1. We find that each relation shows a break at Vrot∗ ∼ 200 km s−1. The central (O/H)0 abundance increases with rising Vrot and the slope of the (O/H)0–Vrot relation is steeper for galaxies with Vrot ≲ Vrot∗. The mean scatter of the central abundances around this relation is 0.053 dex. The relation between the abundance at the optical radius of a galaxy and its rotation velocity is similar; the mean scatter in abundances around this relation is 0.081 dex. The radial abundance gradient expressed in dex/kpc flattens with the increase of the rotation velocity. The slope of the relation is very low for galaxies with Vrot ≳ Vrot∗. The abundance gradient expressed in dex/R25 is roughly constant for galaxies with Vrot ≲ Vrot∗, flattens towards Vrot∗, and then again is roughly constant for galaxies with Vrot ≳ Vrot∗. The change of the gradient expressed in terms of dex/hd (where hd is the disc scale length), in terms of dex/Re, d (where Re, d is the disc effective radius), and in terms of dex/Re, g (where Re, g is the galaxy effective radius) with rotation velocity is similar to that for gradient in dex/R25. The relations between abundance characteristics and other basic parameters (stellar mass, luminosity, and radius) are also considered.

scholarly journals Scale Length of Disk Galaxies

2010 ◽  
Vol 6 (S277) ◽  
pp. 317-320
Author(s):  
Kambiz Fathi
Keyword(s):  
Galaxy Formation ◽  
Surface Brightness ◽  
Sloan Digital Sky Survey ◽  
Disk Galaxies ◽  
Test Bed ◽  
Massive Galaxies ◽  
Central Surface ◽  
Galaxy Formation And Evolution ◽  
The Galaxy ◽  
Scale Length

AbstractDisk scale length rd and central surface brightness μ0 for a sample of 29955 bright disk galaxies from the Sloan Digital Sky Survey have been analyzed. Cross correlation of the SDSS sample with the LEDA catalogue allowed us to investigate the variation of the scale lengths for different types of disk/spiral galaxies and present distributions and typical trends of scale lengths all the SDSS bands with linear relations that indicate the relation that connect scale lengths in one passband to another. We use the volume corrected results in the r-band and revisit the relation between these parameters and the galaxy morphology, and find the average values 〈rd〉 = 3.8 ± 2.1 kpc and 〈μ0〉 = 20.2 ± 0.7 mag arcsec−2. The derived scale lengths presented here are representative for a typical galaxy mass of 1010.8 M⊙, and the RMS dispersion is larger for more massive galaxies. We analyse the rd–μ0 plane and further investigate the Freeman Law and confirm that it indeed defines an upper limit for μ0 in bright disks (rmag < 17.0), and that disks in late type spirals (T ≥ 6) have fainter central surface brightness. Our results are based on a sample of galaxies in the local universe (z < 0.3) that is two orders of magnitudes larger than any sample previously studied, and deliver statistically significant results that provide a comprehensive test bed for future theoretical studies and numerical simulations of galaxy formation and evolution.

scholarly journals A connection between bulge properties and the bimodality of galaxies

2007 ◽  
Vol 3 (S245) ◽  
pp. 67-70
Author(s):  
Niv Drory ◽  
David B. Fisher
Keyword(s):  
Surface Brightness ◽  
Structural Parameters ◽  
Formation Mechanisms ◽  
Disk Galaxies ◽  
Central Surface ◽  
Detailed Surface ◽  
The Galaxy ◽  
Blue Galaxies ◽  
Nearby Galaxies ◽  
Red Galaxies

AbstractThe global colors and structure of galaxies have recently been shown to follow bimodal distributions. Galaxies separate into a “red sequence”, populated prototypically by early-type galaxies, and a “blue cloud”, whose typical objects are late-type disk galaxies. Intermediate-type (Sa-Sbc) galaxies populate both regions. It has been suggested that this bimodality reflects the two-component nature of disk-bulge galaxies. However, it has now been established that there are two types of bulges: “classical bulges” that are dynamically hot systems resembling (little) ellipticals, and “pseudobulges”, dynamically cold, flattened, disk-like structures that could not have formed via violent relaxation. Alas, given the different formation mechanisms of these bulges, the question is whether at types Sa-Sbc, where both bulge types are found, the red-blue dichotomy separates galaxies at some value of disk-to-bulge ratio,B/T, or, whether it separates galaxies of different bulge type, irrespective of theirB/T. In this paper, we identify classical bulges and pseudobulges morphologically with HST images in a sample of nearby galaxies. Detailed surface photometry reveals that: (1) The red – blue dichotomy is a function of bulge type: at the sameB/T, pseudobulges are in globally blue galaxies and classical bulges are in globally red galaxies. (2) Bulge type also predicts where the galaxy lies in other (bimodal) global structural parameters: global Sérsic index and central surface brightness. Hence, the red – blue dichotomy is not due to decreasing bulge prominence alone, and the bulge type of a galaxy carries significance for the galaxy's evolutionary history.

scholarly journals Lenses and Low Surface Brightness Disks

1983 ◽  
Vol 100 ◽  
pp. 253-254
Author(s):  
A. Bosma
Keyword(s):  
Surface Brightness ◽  
Disk Galaxies ◽  
Selection Effects ◽  
Central Surface ◽  
Low Surface Brightness ◽  
The Galaxy ◽  
Intrinsic Scatter ◽  
Limiting Surface ◽  
Disk Component ◽  
Exponential Disk

The 21.65-“law” for disk galaxies has been debated ever since Freeman's (1970) paper in which he found that for 28 out of 36 galaxies the extrapolated central surface brightness of the exponential disk component I0, follows this rule with little intrinsic scatter. Some people think it significant, while others invoke selection effects. Bosma and Freeman (1982) made a new attempt to clarify this problem by studying ratios of diameters of disk galaxies on the various Sky Surveys in a region of overlap. The limiting surface brightness levels were calibrated to be 24.6 and 25.6 magn/arcsec2 for the Palomar blue prints and the SRC J films, resp. The distribution of the ratio Γ = diameter (SRC) / diameter (PAL) gives a measure of the true distribution of Io if the galaxy has an exponential disk in the brightness interval 24.6 to 25.6; e.g. Io = 21.6 corresponds to Γ = 1.32, Io = 22.6 to Γ = 1.50 and Io = 23.6 to Γ = 1.90, etc.

scholarly journals Evidence for azimuthal variations of the oxygen-abundance gradient tracing the spiral structure of the galaxy HCG 91c

2017 ◽  
Vol 601 ◽  
pp. A61 ◽  
Author(s):  
F. P. A. Vogt ◽  
E. Pérez ◽  
M. A. Dopita ◽  
L. Verdes-Montenegro ◽  
S. Borthakur
Keyword(s):  
Spiral Structure ◽  
Oxygen Abundance ◽  
Abundance Gradient ◽  
The Galaxy

scholarly journals A star-forming dwarf galaxy candidate in the halo of NGC 4634

2018 ◽  
Vol 620 ◽  
pp. A29 ◽  
Author(s):  
Y. Stein ◽  
D. J. Bomans ◽  
P. Kamphuis ◽  
E. Jütte ◽  
M. Langener ◽  
...  
Keyword(s):  
Star Formation Rate ◽  
Dwarf Galaxy ◽  
Formation Rate ◽  
Disk Galaxies ◽  
Oxygen Abundance ◽  
Star Forming ◽  
The Galaxy ◽  
Galaxy Disk ◽  
Projected Distance

Context. The halos of disk galaxies form a crucial connection between the galaxy disk and the intergalactic medium. Massive stars, H II regions, or dwarf galaxies located in the halos of galaxies are potential tracers of recent accretion and/or outflows of gas, and are additional contributors to the photon field and the gas phase metallicity. Aims. We investigate the nature and origin of a star-forming dwarf galaxy candidate located in the halo of the edge-on Virgo galaxy NGC 4634 with a projected distance of 1.4 kpc and a Hα star formation rate of ∼4.7 × 10−3 M⊙ yr−1 in order to increase our understanding of these disk-halo processes. Methods. With optical long-slit spectra we measured fluxes of optical nebula emission lines to derive the oxygen abundance 12 + log(O/H) of an H II region in the disk of NGC 4634 and in the star-forming dwarf galaxy candidate. Abundances derived from optical long-slit data and from Hubble Space Telescope (HST) r-band data, Hα data, Giant Metrewave Radio Telescope (GMRT) H I data, and photometry of SDSS and GALEX data were used for further analysis. With additional probes of the luminosity–metallicity relation in the B-band from the Hα-luminosity, the H I map, and the relative velocities, we are able to constrain a possible origin of the dwarf galaxy candidate. Results. The high oxygen abundance (12 + log(O/H) ≈ 8.72) of the dwarf galaxy candidate leads to the conclusion that it was formed from pre-enriched material. Analysis of auxiliary data shows that the dwarf galaxy candidate is composed of material originating from NGC 4634. We cannot determine whether this material has been ejected tidally or through other processes, which makes the system highly interesting for follow up observations.

scholarly journals The Surface Brightness of Our Galaxy and Other Spirals

1990 ◽  
Vol 139 ◽  
pp. 85-97
Author(s):  
P. C. van der Kruit
Keyword(s):  
Distribution Function ◽  
Surface Brightness ◽  
Large Scale ◽  
Spiral Galaxies ◽  
Hubble Constant ◽  
Central Surface ◽  
The Galaxy ◽  
Scale Length

In this review I discuss some aspects of the luminosity distributions in our Galaxy and external spiral galaxies. The major conclusions are the following: (1) the radial scale length of the luminosity distribution in the disk of our Galaxy is 5.0 ± 0.5 kpc, (2) on this basis the Hubble constant needs to be at most 65 ± 10 km s−1 Mpc−1, if our Galaxy and M31 are among the largest spirals, as the Fisher-Tully relation suggests, (3) the probable Hubble type of the Galaxy is SbI–II, (4) the bi-modal distribution function of face-on, central surface brightness μ0 and radial scale length h of spirals shows a preferred value for μ0 of about 22 B-mag arcsec2 and a distribution of h that declines with one e-folding per kpc, (5) the Galaxy is a normal, fairly large Sb galaxy, and (6) galaxies similar to our own in terms of large-scale, nonmorphological properties are NGC 891 and NGC 5033.

scholarly journals A large sample of low surface brightness disk galaxies from SDSS

2008 ◽  
Vol 4 (S252) ◽  
pp. 131-132
Author(s):  
G. H. Zhong ◽  
Y. C. Liang ◽  
L. C. Deng ◽  
B. Zhang
Keyword(s):  
Surface Brightness ◽  
Stellar Populations ◽  
Disk Galaxies ◽  
Large Sample ◽  
Central Surface ◽  
Main Galaxy ◽  
Low Surface Brightness ◽  
Galaxy Sample

AbstractWe present the properties of a large sample (12,282) of nearly face-on low surface brightness disk galaxies selected from the main galaxy sample of SDSS-DR4. Those properties includes B-band central surface brightness μ0(B), scale lengths h, distances D, integrated magnitudes, colors and some resulted relations. This sample has μ0(B) from 22 to 24.5 mag arcsec−2 with a median value of 22.44 mag arcsec−2. They are quite bright with MB taking values from −18 to −23 mag with a median value of −20.08 mag. The disk scale lengths h are from 2 kpc to 19 kpc. There exist clear correlations between log h and MB, log h and log D. Both the optical-optical and optical-NIR color-color relations show most of them have a mix of young and old stellar populations.

On the central surface brightness problem in disk galaxies

1993 ◽  
Vol 106 ◽  
pp. 1394 ◽  
Author(s):  
A. Bosma ◽  
K. C. Freeman
Keyword(s):  
Surface Brightness ◽  
Disk Galaxies ◽  
Central Surface

scholarly journals Simulating non-axisymmetric flows in disk galaxies

2018 ◽  
Vol 618 ◽  
pp. A106 ◽  
Author(s):  
T. H. Randriamampandry ◽  
N. Deg ◽  
C. Carignan ◽  
L. M. Widrow
Keyword(s):  
Surface Brightness ◽  
Initial Conditions ◽  
Major Axis ◽  
Second Step ◽  
Disk Galaxies ◽  
Distribution Models ◽  
Step Method ◽  
Barred Galaxies ◽  
The Galaxy ◽  
Oriented Parallel

Context. We present a two-step method to simulate and study non-circular motions in strongly barred galaxies. The first step is to constrain the initial parameters using a Bayesian analysis of each galaxy’s azimuthally averaged rotation curve, the 3.6 μm surface brightness, and the gas surface density. The second step is to generate equilibrium models using the GalactICS code and evolve them via GADGET-2. Aims. The bar strengths and mock velocity maps of the resulting snapshots are compared to observations in order to determine the best representation of the galaxy. Methods. We apply our method to the unbarred galaxy NGC 3621 and the barred galaxies NGC 1300 and NGC 1530. NGC 3621 provides a validation of our method of generating initial conditions. NGC 1530 has an intermediate bar orientation that allows for a comparison to DiskFit. Finally NGC 1300 has a bar oriented parallel to the galaxy’s major axis, where other algorithms tend to fail. Results. Our models for NGC 3621 and NGC 1530 are comparable to those obtained using commonly available algorithms. Moreover, we produce one of the first mass distribution models for NGC 1300.

Sign in / Sign up

Export Citation Format

Share Document