Distribution Of Central Surface Brightnesses Research Articles

Galaxy disc central surface brightness distribution in the optical and near-infrared bands

To study the disc central surface brightness ($\mu_0$) distribution in optical and near-infrared bands, we select 708 disc-dominated galaxies within a fixed distance of 57 Mpc from SDSS DR7 and UKIDSS DR10. Then we fit $\mu_0$ distribution by using single and double Gaussian profiles with an optimal bin size for the final sample of 538 galaxies in optical $griz$ bands and near-infrared $YJHK$ bands. Among the 8 bands, we find that $\mu_{0}$ distribution in optical bands can not be much better fitted with double Gaussian profiles. However, for all the near-infrared bands, the evidence of being better fitted by using double Gaussian profiles is positive. Especially for $K$ band, the evidence of a double Gaussian profile being better than a single Gaussian profile for $\mu_{0}$ distribution is very strong, the reliability of which can be approved by 1000 times test for our sample. No dust extinction correction is applied. The difference of $\mu_{0}$ distribution between optical and near-infrared bands could be caused by the effect of dust extinction in optical bands. Due to the sample selection criteria, our sample is not absolutely complete. However, the sample incompleteness does not change the double Gaussian distribution of $\mu_{0}$ in $K$ band. Furthermore, we discuss some possible reasons for the fitting results of $\mu_{0}$ distribution in $K$ band. Conclusively, the double Gaussian distribution of $\mu_{0}$ in $K$ band for our sample may depend on bulge-to-disk ratio, color and disk scalelength, rather than the inclination of sample galaxies, bin size and statistical fluctuations.

Illuminating Low Surface Brightness Galaxies with the Hyper Suprime-Cam Survey

Abstract We present a catalog of extended low surface brightness galaxies (LSBGs) identified in the Wide layer of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). Using the first ∼200 deg2 of the survey, we have uncovered 781 LSBGs, spanning red (g − i ≥ 0.64) and blue (g − i < 0.64) colors and a wide range of morphologies. Since we focus on extended galaxies (r eff = 2.″5–14″), our sample is likely dominated by low-redshift objects. We define LSBGs to have mean surface brightnesses mag arcsec−2, which allows nucleated galaxies into our sample. As a result, the central surface brightness distribution spans a wide range of μ 0(g) = 18–27.4 mag arcsec−2, with 50% and 95% of galaxies fainter than 24.3 and 22 mag arcsec−2, respectively. Furthermore, the surface brightness distribution is a strong function of color, with the red distribution being much broader and generally fainter than that of the blue LSBGs, and this trend shows a clear correlation with galaxy morphology. Red LSBGs typically have smooth light profiles that are well characterized by single-component Sérsic functions. In contrast, blue LSBGs tend to have irregular morphologies and show evidence for ongoing star formation. We cross-match our sample with existing optical, H i, and ultraviolet catalogs to gain insight into the physical nature of the LSBGs. We find that our sample is diverse, ranging from dwarf spheroidals and ultradiffuse galaxies in nearby groups to gas-rich irregulars to giant LSB spirals, demonstrating the potential of the HSC-SSP to provide a truly unprecedented view of the LSBG population.

Bimodality of galaxy disc central surface brightness distribution in the Spitzer 3.6 μm band

We report on measurements of the disk central surface brightnesses (mu0) at 3.6 microns for 438 galaxies selected by distance and absolute magnitude cutoffs from the 2350+ galaxies in the Spitzer Survey of Stellar Structure in Galaxies (S4G), one of the largest and deepest homogeneous mid-infrared datasets of nearby galaxies. Our sample contains nearly 3 times more galaxies than the most recent study of the mu0 distribution. We demonstrate that there is a bimodality in the distribution of mu0. Between the low and high surface brightness galaxy regimes there is a lack of intermediate surface brightness galaxies. Caveats invoked in the literature from small number statistics to the knowledge of the environmental influences, and possible biases from low signal to noise data or corrections for galaxy inclination are investigated. Analyses show that the bimodal distribution of mu0 cannot be due to any of these biases or statistical fluctuations. It is highly probable that galaxies settle in two stable modes: a dark matter dominated mode where the dark matter dominates at all radii - this gives birth to low surface brightness galaxies - and a baryonic matter dominated mode where the baryons dominate the dark matter in the central parts - this gives rise to the high surface brightness disks. The lack of intermediate surface brightness objects suggests that galaxies avoid (staying in) a mode where dark matter and baryons are co-dominant in the central parts of galaxies.

The Space Density of Galaxies through \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $\mu _{B}( 0) =25.0$ \end{document} Magnitudes per Inverse Arcsecond Squared

Using the catalog of O'Neil, Bothun, & Schombert, we examine the central surface brightness distribution ([μB(0)]) of galaxies in the 22.0 ≤ μB(0) ≤ 25.0 mag arcsec-2 range. Taking advantage of having a catalog in which each galaxy has a known central surface brightness, scale length, and redshift, we apply a bivariate volume correction to the data and extend the surface brightness distribution function by 1 magnitude, to 25.0 B mag arcsec-2. The result is a flat (slope = 0) space density of galaxies as a function of μB(0) from the Freeman value of 21.65 ± 0.30 to the survey limit of 25.0 mag arcsec-2, more than 10 σ away. The galaxies that comprise this sample have scale lengths and circular velocities similar to L* spiral galaxies (i.e., these are not dwarf galaxies). As such, a significant amount of mass is contained in this population. If the baryonic mass fraction of disk galaxies is independent of μB(0), then our results are consistent with a significant percentage of the baryonic content of the universe being contained in potentials only dimly lit by the embedded galaxy.

The Ursa Major Cluster of Galaxies. II. Bimodality of the Distribution of Central Surface Brightnesses

The Ursa Major Cluster appears to be unevolved and made up of HI-rich spiral galaxies. B,R,I,K' photometry has been obtained for 79 galaxies, including 62 in a complete sample with M(B)<-16.5 mag. The K' information is particularly important for the present discussion because it is not seriously affected by obscuration. There is reasonably convincing evidence that the distribution of exponential disk central surface brightnesses is bimodal. Disks avoid the domain between the high and low surface brightness zones. The few intermediate surface brightness examples in the sample all have significant nearby neighbors. The high surface brightness (HSB) galaxies exhibit a range -21<M(B)<-17 while the low surface brightness (LSB) galaxies are found with -19<M(B) down to the completion limit. HSB and LSB galaxies in the overlap regime -19<M(B)<-17 that are indistinguishable in luminosity-line width plots have very distinct locations in surface brightness-scale length plots. The existence of separate HSB and LSB families suggests that there are discrete radial configurations that are stable. Galaxies are driven into one of these regimes. The HSB state has a lower luminosity cutoff. It is likely that the HSB galaxies are dominated by dissipational matter at their centers while the LSB galaxies are dark matter dominated. The HSB family subdivides into those with, and without, substantial bulges. Evidently, there are two thresholds probably controlled by angular momentum content or transfer. Passing from high to low specific angular momentum, there is first the transition from LSB to HSB regimes, then the transition from exponential disk to disk plus bulge regimes.

Low Surface Brightness Galaxies in the Local Universe. II. Selection Effects and Completeness of the Automated Plate Measuring Survey

view Abstract Citations (33) References (26) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Low Surface Brightness Galaxies in the Local Universe. II. Selection Effects and Completeness of the Automated Plate Measuring Survey Sprayberry, D. ; Impey, C. D. ; Irwin, M. J. Abstract We discuss the techniques employed for identifying low surface brightness galaxies for the Automated Plate Measuring (APM) survey. We present the method of calibrating the photometry performed from the APM scans and discuss the uncertainties associated with the calibrations. We also review the possible sources of incompleteness in the survey, and we present the results of a program of simulations to estimate the completeness as a function of galaxy parameters. Finally, we discuss the implications of the survey results and show, in particular, that the observed distribution of central surface brightnesses among all galaxies in one survey field is almost flat for μ_B_(0) > 23 mag arcsec^-2^. Publication: The Astrophysical Journal Pub Date: June 1996 DOI: 10.1086/177268 Bibcode: 1996ApJ...463..535S Keywords: GALAXIES: PHOTOMETRY; METHODS: DATA ANALYSIS; SURVEYS full text sources ADS | data products NED (2) Related Materials (4) Part 1: 1996ApJS..105..209I Part 3: 1997ApJ...482..104S Part 4: 2001AJ....122.2341I Part 5: 2001AJ....122.2318B

X-Ray Binaries in Globular Clusters

X-ray binaries in globular clusters provide a powerful tool for the exploration of the evolution of compact binaries and their host globular clusters. Recent x-ray and optical studies of these systems have yielded long-sought binary periods and fundamental properties for two sources (in NGC 6624 and M 15). It appears that tidal capture formation of compact binaries in globular clusters can proceed by several different routes and lead to exotic systems such as the white dwarf-neutron star binary with an 11-minute period recently discovered in NGC 6624. Combined with previously reported long-term periods for several globular cluster (and field) x-ray sources, this suggests again that many of these systems may in fact be hierarchical triple systems. The prospects for forming these in the dense cores of clusters undergoing core collapse is discussed, and searches for color gradients in the cores of globular clusters showing cusps in their central surface brightness distribution are presented. A program to test for the high central density of binaries (and triples) expected in cusp clusters by searching for diffuse line emission from their constituent cataclysmic variables is briefly described. Finally, the case for globular cluster disruption and the formation of galactic x-ray burst source is reviewed in light of recent developments.

The Velocity Dispersion of M 4 Horizontal-Branch Stars

Radial velocities have been measured for nine blue horizontal-branch stars in the globular cluster M 4. Their mean velocity is 72.3 ± 0.9 km/s, and their velocity dispersion (after removal of the ±1.5 km/s random error on an individual measurement) is 1.9 ± 0.3 km/s. The observed dispersion is considerably smaller than the value of 4.4 km.s inferred by Peterson and King (1975) from their fit of a King model to the central surface brightness distribution, assuming a solar mass-to-light ratio. This new measurement is more discrepant with such a fit than that noted by Petrson and King, who relied upon the central velocity dispersions measured in integrated light by Illingworth (1976). Of necessity, the clusters studied by Illingworth are highly centrally concentrated, while M 4 is of rather low central concentration. This new result raises the possibility that M 4 in particular, and low-concentration clusters in general, may have mass-to-light ratios that are less than solar. This suggestion should be checked using accurate measurements (to better than 1 km/s) of the velocities of a dozen giants in this and other low-concentration clusters.