A5063312800- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Blind Source Separation Techniques
- Research in Social Sciences
- Astrophysics and Star Formation Studies
- CCD and CMOS Imaging Sensors
- Advanced Vision and Imaging
- Spectroscopy and Chemometric Analyses
- American and British Literature Analysis
- Natural Language Processing Techniques
- Service-Oriented Architecture and Web Services
- Advanced Fluorescence Microscopy Techniques
- Numerical methods for differential equations
- Remote Sensing and LiDAR Applications
- Comparative Literary Analysis and Criticism
- European history and politics
- Cinema and Media Studies
- Radio Astronomy Observations and Technology
- Indian and Buddhist Studies
- Shakespeare, Adaptation, and Literary Criticism
- Digital Humanities and Scholarship
Universität Hamburg
2018-2019
University of Oulu
2010-2018
Universidad Nacional Autónoma de México
2018
University of Turku
2010-2015
Turku Centre for Computer Science
2011-2015
The Spitzer Survey of Stellar Structure in Galaxies S^4G is an Exploration Science Legacy Program approved for the post-cryogenic mission. It a volume-, magnitude-, and size-limited (d < 40 Mpc, |b| > 30 degrees, m_(Bcorr) 15.5, D25>1') survey 2,331 galaxies using IRAC at 3.6 4.5 microns. Each galaxy observed 240 s mapped to 1.5 x D25. final mosaicked images have typical 1 sigma rms noise level 0.0072 0.0093 MJy / sr microns, respectively. Our azimuthally-averaged surface brightness profile...
The Spitzer Survey of Stellar Structure in Galaxies (S^4G) is a deep 3.6 and 4.5 μm imaging survey 2352 nearby (<40 Mpc) galaxies. We describe the S(^4)G data analysis pipeline 4, which dedicated to two-dimensional structural surface brightness decompositions images, using GALFIT3.0. Besides automatic 1-component Sersic fits, 2-component bulge + exponential disk we present human-supervised multi-component decompositions, include, when judged appropriate, central point source, bulge, disk,...
We present a new approach for estimating the 3.6 micron stellar mass-to-light ratio in terms of [3.6]-[4.5] colors old populations. Our avoids several largest sources uncertainty existing techniques. By focusing on mid-IR wavelengths, we gain virtually dust extinction-free tracer stars, avoiding need to adopt model correctly interpret optical or optical/NIR normally leveraged assign M/L. calibrating relation between NIR and GLIMPSE giant stars also avoid discrepancies predictions populations...
With the aim of constructing accurate 2D maps stellar mass distribution in nearby galaxies from S4G 3.6 and 4.5 micron images, we report on separation light old stars emission contributed by contaminants (e.g. hot dust 3.3 PAH feature). Results for a small sample six disk (NGC 1566, NGC 2976, 3031, 3184, 4321, 5194) with range morphological properties, contents star formation histories are presented to demonstrate our approach. We use an Independent Component Analysis (ICA) technique...
The Spitzer Survey of Stellar Structure in Galaxies (S4G) is the largest available database deep, homogeneous middle-infrared (mid-IR) images galaxies all types. survey, which includes 2352 nearby galaxies, reveals galaxy morphology only minimally affected by interstellar extinction. This paper presents an atlas and classifications S4G Comprehensive de Vaucouleurs revised Hubble-Sandage (CVRHS) system. CVRHS system follows precepts classical (1959) morphology, modified to include recognition...
The Spitzer Survey of Stellar Structure in Galaxies is a volume, magnitude, and size-limited survey 2352 nearby galaxies with deep imaging at 3.6 4.5 μm.In this paper, we describe our surface photometry pipeline showcase the associated data products that have released to community.We also identify physical mechanisms leading different levels central stellar mass concentration for same total mass.Finally, derive local mass-size relation μm morphologies.Our radial profiles reach densities...
The mid-infrared is an optimal window to trace stellar mass in nearby galaxies and the 3.6$\mu m$ IRAC band has been exploited this effect, but such estimates can be biased by dust emission. We present our pipeline reveal old flux at obtain maps for more than 1600 available from Spitzer Survey of Stellar Structure Galaxies (S$^{4}$G). This survey consists images two infrared bands (3.6 4.5$\mu m$), we use Independent Component Analysis (ICA) method presented Meidt et al. (2012) separate...
We have analyzed the radial distribution of old stars in a sample 218 nearby face-on disks, using deep 3.6 μm images from Spitzer Survey Stellar Structure Galaxies. In particular, we studied structural properties those disks with broken or down-bending profile. find that, on average, genuine single-exponential profile scale length and central surface brightness which are intermediate to inner outer components disk same total stellar mass. particular case barred galaxies, ratio between break...
Most, if not all, disk galaxies have a thin (classical) and thick disk. In most models disks are thought to be necessary consequence of the formation and/or evolution galaxy. We present results study properties in sample carefully selected edge-on with types ranging from T = 3 8. fitted one-dimensional luminosity profiles physically motivated functions—the solutions two stellar one gaseous isothermal coupled equilibrium—which likely yield more accurate than other functions used previous...
Breaks in the radial luminosity profiles of galaxies have until now been mostly studied averaged over disks. Here, we study separately breaks thin and thick disks 70 edge-on using imaging from Spitzer Survey Stellar Structure Galaxies. We built parallel to midplanes found that often truncate (77%). Thick less (31%), but when they do, their break radius is comparable with disk. This suggests either two different truncation mechanisms—one dynamical origin affecting both simultaneously another...
Spiral arm properties of 46 galaxies in the Spitzer Survey Stellar Structure Galaxies (S4G) were measured at 3.6 μm, where extinction is small and old stars dominate. The sample includes flocculent, multiple arm, grand design types with a wide range Hubble bar types. We find that most optically flocculent are also mid-IR because star formation uncorrelated stellar density waves, whereas have underlying waves. Arm–interarm contrasts increase from to later can be traced further out disk than...
Resonance rings are the consequence of secular evolution processes that redistribute material and angular momentum in discs. We produced a Catalogue an Atlas detected Spitzer Survey Stellar Structure Galaxies (S4G) to conduct statistical study data Catalogue. traced contours previously identified by Buta et al. (in preparation) fitted them with ellipses. found orientation bars studying galaxy ellipse fits from S4G's Pipeline 4. used obtained 4 obtain intrinsic ellipticities orientations...
We study the surface brightness profiles of disc galaxies in 3.6 μm images from Spitzer Survey Stellar Structure Galaxies (S4G) and Ks-band Near-Infrared S0-Sa galaxy (NIRS0S). particularly connect properties single exponential (type I), downbending double II), upbending III) profile types, to structural components by using detailed morphological classifications, size measurements rings lenses. also how local environment affects types calculating parameters describing environmental density...
The mechanism causing breaks in the radial surface brightness distribution of spiral galaxies is not yet well known. Despite theoretical efforts, there a unique explanation for these features and observational results are conclusive. In an attempt to address this problem, we have selected sample 34 highly inclined present both Sloan Digital Sky Survey Spitzer Stellar Structure Galaxies. We measured profiles five optical bands 3.6$\mu m$ band. also calculated color stellar mass density using...
We combine data from the Spitzer Survey for Stellar Structure in Galaxies, a recently calibrated empirical stellar mass estimator Eskew et al., and an extensive database of H i spectral line profiles to examine baryonic Tully–Fisher (BTF) relation. find (1) that BTF has lower scatter than classic (TF) relation is better described as linear relationship, confirming similar previous results, (2) inclusion radial scale decreases but only modestly, seen previously TF relation, (3) slope BTF,...
Stellar bars can lead to gas inflow toward the center of a galaxy and stimulate nuclear star formation. However, there is no compelling evidence on whether they also feed central supermassive black hole: by measuring fractions barred active inactive galaxies, previous studies have yielded conflicting results. In this paper, we aim understand lack observational for bar-driven galactic nucleus (AGN) activity studying sample 41 nearby (d < 35 Mpc) galaxies from Spitzer Survey Structure in...
We have performed two-dimensional multicomponent decomposition of 144 local barred spiral galaxies using 3.6 $\mu {\rm m}$ images from the Spitzer Survey Stellar Structure in Galaxies. Our model fit includes up to four components (bulge, disk, bar, and a point source) and, most importantly, takes into account disk breaks. find that ignoring break single scale length for Type II (down-bending) can lead differences 40% length, 10% bulge-to-total luminosity ratio (B/T), 25% bar-to-total ratios....
We study the m=1 distortions (lopsidedness) in stellar components of 167 nearby galaxies that span a wide range morphologies and luminosities. confirm previous findings 1) high incidence lopsidedness distributions, 2) increasing as function radius out to at least 3.5 exponential scale lengths, 3) greater lopsidedness, over these radii, for later type lower surface brightness. Additionally, magnitude correlates with character spiral arms (stronger arm patterns occur less lopsidedness), is not...
The Spitzer Survey of Stellar Structure in Galaxies (S^4G), together with its Early Type Galaxy (ETG) extension, stands as the most extensive dataset deep uniform mid-infrared (mid-IR; 3.6 and 4.5$,μm) imaging for a sample 2817$ nearby (d<40 ,Mpc) galaxies. However, velocity criterion used to select original results an additional 422 galaxies without i detection that should have been included S^4G on basis their optical recession velocities. In order create complete magnitude-, size-,...
Tidal debris around galaxies can yield important clues on their evolution. We have identified tidal in 11 early-type (T ⩽ 0) from a sample of 65 early types drawn the Spitzer Survey Stellar Structure Galaxies (S4G). The includes features such as shells, ripples, and tails. A variety techniques, including two-dimensional decomposition galactic structures, were used to quantify residual features. contributes ∼3%–10% total 3.6 μm luminosity host galaxy. Structural parameters estimated using...
The morphology of galaxies can be quantified to some degree using a set scale-invariant parameters. Concentration (C), Asymmetry (A), Smoothness (S), the Gini index (G), relative contribution brightest pixels second order moment flux (M20), ellipticity (E), and (GM) have all been applied morphologically classify at various wavelengths. Here we present catalog these parameters for Spitzer Survey Stellar Structure in Galaxies (S4G), volume-limited near-infrared imaging survey nearby 3.6 4.5...
Using a sample of 472 local Universe (z<0.06) galaxies in the stellar mass range 10.25 < log M*/M_sun 10.75, we explore variation galaxy structure as function morphology and colour. Our is sub-divided into red, green blue colour groups elliptical non-elliptical (disk-type) morphologies. KiDS VIKING derived postage stamp images, group eight volunteers visually classified bars, rings, morphological lenses, tidal streams, shells signs merger activity for all systems. We find significant...
Breaks in the surface brightness profiles outer regions of galactic discs are thought to have formed by various internal and external processes, studying breaks we aim better understand what processes responsible for evolution discs. We use a large well-defined sample study how common are, whether their properties depend on galaxy stellar mass or observed wavelength. radial 753 galaxies, obtained from $3.6 \mu m$ images Spitzer Survey Stellar Structure Galaxies (S$^4$G), $K_s$-band data Near...
Aims: Using a sample of 175 low-inclination galaxies from the S$^{4}$G, we investigate origins up-bending (Type III) breaks in 3.6 $\mu$m surface brightness profiles disk galaxies. Methods: We re-analyze previously identified Type III break-hosting using new, unbiased break-finding algorithm, which uncovered many sometimes subtle across whole sample. classify each break by its likely origin through close examination galaxy images wavelengths, and compare samples separated their outermost...
NGC 4013 is a nearby Sb edge-on galaxy known for its "prodigious" HI warp and "giant" tidal stream. Previous work on this unusual object shows that it cannot be fitted satisfactorily by canonical thin+thick disk structure. We have produced new decomposition of 4013, considering three stellar flattened components (thin+thick plus an extra more extended component) one gaseous disk. All four are considered to gravitationally coupled isothermal. To do so, we used the 3.6micron images from...