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Articles 1 - 9 of 9
Full-Text Articles in Physical Sciences and Mathematics
A Normal Supermassive Black Hole In Ngc 1277, Alister W. Graham, Mark Durré, Giulia A.D. Savorgnan, Anne M. Medling, Dan Batcheldor, Nicholas Scott, Beverly Watson, Alessandro Marconi
A Normal Supermassive Black Hole In Ngc 1277, Alister W. Graham, Mark Durré, Giulia A.D. Savorgnan, Anne M. Medling, Dan Batcheldor, Nicholas Scott, Beverly Watson, Alessandro Marconi
Aerospace, Physics, and Space Science Faculty Publications
The identification of galaxies with “overly massive” black holes requires two measurements: a black hole mass (Mbh) and a host spheroid mass (Msph,*). Here we provide our measurements for NGC 1277. Our structural decomposition reveals that NGC 1277 is dominated by a “classical” spheroid with a Sérsic index n = 5.3, a half-light radius Rₑmajor: You have a new taskSpace: You have a new task,major = 2.1 kpc, and a stellar mass of 2.7 10^11 11 M⊙ (using M*/ LV = 11.65, Martín-Navarro et al.). This mass is an order of magnitude greater than originally reported. Using the latest Mbh–n, …
A Classical Morphological Analysis Of Galaxies In The Spitzer Survey Of Stellar Structure In Galaxies (S4g), Ronald J. Buta, Trisha Mizusawa
A Classical Morphological Analysis Of Galaxies In The Spitzer Survey Of Stellar Structure In Galaxies (S4g), Ronald J. Buta, Trisha Mizusawa
Aerospace, Physics, and Space Science Faculty Publications
The Spitzer Survey of Stellar Structure in Galaxies (S4G) is the largest available database of deep, homogeneous middle-infrared (mid-IR) images of galaxies of all types. The survey, which includes 2352 nearby galaxies, reveals galaxy morphology only minimally affected by interstellar extinction. This paper presents an atlas and classifications of S4G galaxies in the Comprehensive de Vaucouleurs revised Hubble-Sandage (CVRHS) system. The CVRHS system follows the precepts of classical de Vaucouleurs morphology, modified to include recognition of other features such as inner, outer, and nuclear lenses, nuclear rings, bars, and disks, spheroidal galaxies, X patterns and box/peanut structures, OLR subclass outer …
The Mass Profile And Shape Of Bars In The Spitzer Survey Of Stellar Structure In Galaxies (S⁴G): Search For An Age Indicator For Bars, Taehyun Kim, Trisha Mizusawa
The Mass Profile And Shape Of Bars In The Spitzer Survey Of Stellar Structure In Galaxies (S⁴G): Search For An Age Indicator For Bars, Taehyun Kim, Trisha Mizusawa
Aerospace, Physics, and Space Science Faculty Publications
We have measured the radial light profiles and global shapes of bars using two-dimensional 3.6μm image decompositions for 144 face-on barred galaxies from the Spitzer Survey of Stellar Structure in Galaxies. The bar surface brightness profile is correlated with the stellar mass and bulge-to-total (B/T) ratio of their host galaxies. Bars in massive and bulge-dominated galaxies (B/T > 0.2) show a flat profile, while bars in less massive, disk-dominated galaxies (B/T ∼ 0) show an exponential, disk-like profile with a wider spread in the radial profile than in the bulge-dominated galaxies. The global two-dimensional shapes of bars, however, are rectangular/boxy, independent …
Reconstructing The Stellar Mass Distributions Of Galaxies Using S4g Irac 3.6 And 4.5 Μm Images. Ii. The Conversion From Light To Mass, Sharon E. Meidt, Trisha F. Mizusawa
Reconstructing The Stellar Mass Distributions Of Galaxies Using S4g Irac 3.6 And 4.5 Μm Images. Ii. The Conversion From Light To Mass, Sharon E. Meidt, Trisha F. Mizusawa
Aerospace, Physics, and Space Science Faculty Publications
We present a new approach for estimating the 3.6 μm stellar mass-to- light (M/L) ratio Υ3.6 in terms of the [3.6]-[4.5] colors of old stellar populations. Our approach avoids several of the largest sources of uncertainty in existing techniques using population synthesis models. By focusing on mid-IR wavelengths, we gain a virtually dust extinction-free tracer of the old stars, avoiding the need to adopt a dust model to correctly interpret optical or optical/near-IR colors normally leveraged to assign the mass-to-light ratio Υ. By calibrating a new relation between near-IR and mid-IR colors of giant stars observed in GLIMPSE we also …
The Baryonic Tully-Fisher Relationship For S4g Galaxies And The "Condensed" Baryon Fraction Of Galaxies, Dennis Zaritsky, Trisha F. Mizusawa
The Baryonic Tully-Fisher Relationship For S4g Galaxies And The "Condensed" Baryon Fraction Of Galaxies, Dennis Zaritsky, Trisha F. Mizusawa
Aerospace, Physics, and Space Science Faculty Publications
We combine data from the Spitzer Survey for Stellar Structure in Galaxies, a recently calibrated empirical stellar mass estimator from Eskew et al., and an extensive database of H I spectral line profiles to examine the baryonic Tully-Fisher (BTF) relation. We find (1) that the BTF has lower scatter than the classic Tully-Fisher (TF) relation and is better described as a linear relationship, confirming similar previous results, (2) that the inclusion of a radial scale in the BTF decreases the scatter but only modestly, as seen previously for the TF relation, and (3) that the slope of the BTF, which …
Unveiling The Structure Of Barred Galaxies At 3.6 Μm With The Spitzer Survey Of Stellar Structure In Galaxies (S4g). I. Disk Breaks, Taehyun Kim, Trisha Mizusawa
Unveiling The Structure Of Barred Galaxies At 3.6 Μm With The Spitzer Survey Of Stellar Structure In Galaxies (S4g). I. Disk Breaks, Taehyun Kim, Trisha Mizusawa
Aerospace, Physics, and Space Science Faculty Publications
We have performed two-dimensional multicomponent decomposition of 144 local barred spiral galaxies using 3.6 μm images from the Spitzer Survey of 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. We find that ignoring the disk break and using a single disk scale length in the model fit for Type II (down-bending) disk galaxies can lead to differences of 40% in the disk scale length, 10% in bulge-to-total luminosity ratio (B/T), and 25% in bar-to-total luminosity ratios. We find that for galaxies …
X-Ray Nuclear Activity In S4g Barred Galaxies: No Link Between Bar Strength And Co-Occurrent Supermassive Black Hole Fueling, Mauricio Cristernas, Trisha Mizusawa
X-Ray Nuclear Activity In S4g Barred Galaxies: No Link Between Bar Strength And Co-Occurrent Supermassive Black Hole Fueling, Mauricio Cristernas, Trisha Mizusawa
Aerospace, Physics, and Space Science Faculty Publications
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 a central supermassive black hole: by measuring the fractions of barred active and inactive galaxies, previous studies have yielded conflicting results. In this paper, we aim to understand the lack of observational evidence for bar-driven active galactic nucleus (AGN) activity by studying a sample of 41 nearby (d < 35 Mpc) barred galaxies from the Spitzer Survey for Stellar Structure in Galaxies. We use Chandra observations to measure nuclear 2–10 keV X-ray luminosities and estimate Eddington ratios, together with Spitzer 3.6 μm imaging to quantify the strength of the stellar bar in two independent ways: (1) from its structure, as traced by its ellipticity and boxiness, and (2) from its gravitational torque Qb, taken as the maximum ratio of the tangential force to the mean background radial force. In this way, rather than discretizing the presence of both stellar bars and nuclear activity, we are able to account for the continuum of bar strengths and degrees of AGN activity. We find nuclear X-ray sources in 31 out of 41 galaxies with median X-ray luminosity and Eddington ratio of LX = 4.3×1038 erg s−1 and Lbol/LEdd = 6.9×10−6, respectively, consistent with low-luminosity AGN activity. Including upper limits for those galaxies without nuclear detections, we find no significant correlation between any of the bar strength indicators and the degree of nuclear activity, irrespective of galaxy luminosity, stellar mass, Hubble type, or bulge size. Strong bars do not favor brighter or more efficient nuclear activity, implying that at least for the low-luminosity regime, supermassive black hole fueling is not closely connected to large-scale features.
The Impact Of Bars On Disk Breaks As Probed By S⁴G Imaging, Juan Carlos Muñoz-Mateos, Trisha Mizusawa
The Impact Of Bars On Disk Breaks As Probed By S⁴G Imaging, Juan Carlos Muñoz-Mateos, Trisha Mizusawa
Aerospace, Physics, and Space Science Faculty Publications
We have analyzed the radial distribution of old stars in a sample of 218 nearby face-on disks, using deep 3.6μm images from the Spitzer Survey of Stellar Structure in Galaxies. In particular, we have studied the structural properties of those disks with a broken or down-bending profile. We find that, on average, disks with a genuine single-exponential profile have a scale length and a central surface brightness which are intermediate to those of the inner and outer components of a down-bending disk with the same total stellar mass. In the particular case of barred galaxies, the ratio between the break …
Breaks In Thin And Thick Disks Of Edge-On Galaxies Imaged In The Spitzer Survey Of Stellar Structure In Galaxies (S4g), Sébastien Comerón, Trisha Mizusawa
Breaks In Thin And Thick Disks Of Edge-On Galaxies Imaged In The Spitzer Survey Of Stellar Structure In Galaxies (S4g), Sébastien Comerón, Trisha Mizusawa
Aerospace, Physics, and Space Science Faculty Publications
Breaks in the radial luminosity profiles of galaxies have until now been mostly studied averaged over disks. Here, we study separately breaks in thin and thick disks in 70 edge-on galaxies using imaging from the Spitzer Survey of Stellar Structure in Galaxies. We built luminosity profiles of the thin and thick disks parallel to midplanes and we found that thin disks often truncate (77%). Thick disks truncate less often (31%), but when they do, their break radius is comparable with that in the thin disk. This suggests either two different truncation mechanisms—one of dynamical origin affecting both disks simultaneously and …