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Articles 1 - 30 of 72
Full-Text Articles in Physical Sciences and Mathematics
Devils: Cosmic Evolution Of Sed-Derived Metallicities And Their Connection To Star Formation Histories, Jessica E. Thorne, Aaron S G Robotham, Sabine Bellstedt, Luke J M Davies, Robin H W Cook, Luca Cortese, Benne Holwerda, Steven Phillipps, Malgorzata Siudek
Devils: Cosmic Evolution Of Sed-Derived Metallicities And Their Connection To Star Formation Histories, Jessica E. Thorne, Aaron S G Robotham, Sabine Bellstedt, Luke J M Davies, Robin H W Cook, Luca Cortese, Benne Holwerda, Steven Phillipps, Malgorzata Siudek
Faculty Scholarship
Gas-phase metallicities of galaxies are typically measured through auroral or nebular emission lines, but metallicity also leaves an imprint on the overall spectral energy distribution (SED) of a galaxy and can be estimated through SED fitting. We use the PROSPECT SED fitting code with a flexible parametric star formation history and an evolving metallicity history to self-consistently measure metallicities, stellar mass, and other galaxy properties for 90 000 galaxies from the Deep Extragalactic VIsible Legacy Survey (DEVILS) and Galaxy and Mass Assembly (GAMA) survey. We use these to trace the evolution of the mass–metallicity relation (MZR) and show that the …
Individual Element Sensitivity For Stellar Evolutionary Isochrones, Guy Worthey, Xiang Shi, Tathagata Pal, Hyun-Chul Lee, Baitian Tang
Individual Element Sensitivity For Stellar Evolutionary Isochrones, Guy Worthey, Xiang Shi, Tathagata Pal, Hyun-Chul Lee, Baitian Tang
Physics and Astronomy Faculty Publications and Presentations
Stellar evolution calculations with variable abundance ratios were used to gauge the effects on temperatures, luminosities, and lifetimes in various phases. The individual elements C, N, O, Mg, Si, and Fe were included. Most of the effect relevant to integrated light models is contained in the temperature variable, as opposed to the time-scale or luminosity. We derive a recipe for including abundance-sensitive temperature effects that is applicable to existing isochrone grids. The resultant enhanced isochrones are incorporated into composite stellar population models and compared with galaxy data from the Sloan Digital Sky Survey. A severe oxygen–age degeneracy is apparent, 2–3 …
Is Ngc 300 A Pure Exponential Disk Galaxy?, In Sung Jang, Roelof S. De Jong, Ivan Minchev, Eric F. Bell, Antonela Monachesi, Benne W. Holwerda, Jeremy Bailin, Adam Smercina, Richard D'Souza
Is Ngc 300 A Pure Exponential Disk Galaxy?, In Sung Jang, Roelof S. De Jong, Ivan Minchev, Eric F. Bell, Antonela Monachesi, Benne W. Holwerda, Jeremy Bailin, Adam Smercina, Richard D'Souza
Faculty Scholarship
NGC 300 is a low-mass disk galaxy in the Sculptor group. In the literature, it has been identified as a pure exponential disk galaxy, as its luminosity profile can be well fit with a single exponential law over many disk scale lengths (Type I). We investigate the stellar luminosity distribution of NGC 300 using Hubble Space Telescope archive data, reaching farther and deeper than any other previous studies. Color-magnitude diagrams show a significant population of old red giant branch (RGB) stars in all fields out to R ∼ 19 kpc (32′), as well as younger populations in the inner regions. …
Galaxy And Mass Assembly (Gama): Defining Passive Galaxy Samples And Searching For The Uv Upturn, S. Phillipps, S. S. Ali, M. N. Bremer, R. De Propris, A. E. Sansom, M. E. Cluver, M. Alpaslan, S. Brough, M. J.I. Brown, L. J.M. Davies, S. P. Driver, M. W. Grootes, Benne W. Holwerda, A. M. Hopkins, P. A. James, K. Pimbblet, A. S.G. Robotham, E. N. Taylor, L. Wang
Galaxy And Mass Assembly (Gama): Defining Passive Galaxy Samples And Searching For The Uv Upturn, S. Phillipps, S. S. Ali, M. N. Bremer, R. De Propris, A. E. Sansom, M. E. Cluver, M. Alpaslan, S. Brough, M. J.I. Brown, L. J.M. Davies, S. P. Driver, M. W. Grootes, Benne W. Holwerda, A. M. Hopkins, P. A. James, K. Pimbblet, A. S.G. Robotham, E. N. Taylor, L. Wang
Faculty Scholarship
We use data from the GAMA and GALEX surveys to demonstrate that the UV upturn, an unexpected excess of ultraviolet flux from a hot stellar component, seen in the spectra of many early-type galaxies, arises from processes internal to individual galaxies with no measurable influence from the galaxies' larger environment. We first define a clean sample of passive galaxies without a significant contribution to their UV flux from low-level star formation. We confirm that galaxies with the optical colours of red sequence galaxies often have signs of residual star formation, which, without other information, would prevent a convincing demonstration of …
Galaxy And Mass Assembly (Gama): Properties And Evolution Of Red Spiral Galaxies, Smriti Mahajan, Kriti Kamal Gupta, Rahul Rana, M. J.I. Brown, S. Phillipps, Joss Bland-Hawthorn, M. N. Bremer, S. Brough, Benne W. Holwerda, A. M. Hopkins, J. Loveday, Kevin Pimbblet, Lingyu Wang
Galaxy And Mass Assembly (Gama): Properties And Evolution Of Red Spiral Galaxies, Smriti Mahajan, Kriti Kamal Gupta, Rahul Rana, M. J.I. Brown, S. Phillipps, Joss Bland-Hawthorn, M. N. Bremer, S. Brough, Benne W. Holwerda, A. M. Hopkins, J. Loveday, Kevin Pimbblet, Lingyu Wang
Faculty Scholarship
We use multiwavelength data from the Galaxy And Mass Assembly (GAMA) survey to explore the cause of red optical colours in nearby (0.002 < z < 0.06) spiral galaxies. We show that the colours of red spiral galaxies are a direct consequence of some environment-related mechanism(s) that has removed dust and gas, leading to a lower star formation rate. We conclude that this process acts on long time-scales (several Gyr) due to a lack of morphological transformation associated with the transition in optical colour. The specific star formation rate (sSFR) and dust-to-stellar mass ratio of red spiral galaxies is found to be statistically lower than blue spiral galaxies. On the other hand, red spirals are on average 0.9 dex more massive, and reside in environments 2.6 times denser than their blue counterparts. We find no evidence of excessive nuclear activity, or higher inclination angles to support these as the major causes for the red optical colours seen in ≳47 per cent of all spirals in our sample. Furthermore, for a small subsample of our spiral galaxies that are detected in H I, we find that the SFR of gas-rich red spiral galaxies is lower by ∼1 dex than their blue counterparts.
The Resolved Stellar Populations Of A Dwarf Spheroidal Galaxy In The Virgo Cluster, Patrick R. Durell, Ted Von Hippel, Et Al.
The Resolved Stellar Populations Of A Dwarf Spheroidal Galaxy In The Virgo Cluster, Patrick R. Durell, Ted Von Hippel, Et Al.
Ted von Hippel
We report on the discovery of a faint (MV ~ -10.6 ± 0.2) dwarf spheroidal galaxy on deep F606W and F814W Hubble Space Telescope images of a Virgo intracluster field. The galaxy is easily resolved in our images, as our color magnitude diagram (CMD) extends 1 magnitude beyond the tip of the red giant branch (RGB). Thus, it is the deepest CMD for a small dwarf galaxy inside a cluster environment. Using the colors of the RGB stars, we derive a metal abundance for the dwarf of [M/H] = -2.3 ± 0.3 and show that the metallicity dispersion …
Spatially Resolved Stellar Populations And Kinematics With Kcwi: Probing The Assembly History Of The Massive Early-Type Galaxy Ngc 1407, Anna Ferré-Mateu, Duncan Forbes, Richard Mcdermid, Aaron Romanowsky, Jean Brodie
Spatially Resolved Stellar Populations And Kinematics With Kcwi: Probing The Assembly History Of The Massive Early-Type Galaxy Ngc 1407, Anna Ferré-Mateu, Duncan Forbes, Richard Mcdermid, Aaron Romanowsky, Jean Brodie
Faculty Publications
Using the newly commissioned Keck Cosmic Web Imager (KCWI) instrument on the Keck II telescope, we analyze the stellar kinematics and stellar populations of the well-studied massive early-type galaxy (ETG) NGC 1407. We obtained high signal-to-noise integral field spectra for a central and an outer (around one effective radius toward the southeast direction) pointing with integration times of just 600 s and 2400 s, respectively. We confirm the presence of a kinematically distinct core also revealed by VLT/MUSE data of the central regions. While NGC 1407 was previously found to have stellar populations characteristic of massive ETGs (with radially constant …
Extreme Chemical Abundance Ratio Suggesting An Exotic Origin For An Ultradiffuse Galaxy, Ignacio Martín-Navarro, Aaron Romanowsky, Jean Brodie, Anna Ferr´E-Mateu, Adebusola Alabi, Duncan Forbes, Margarita Sharina, Alexa Villaume, Viraj Pandya, David Martinez-Delgado
Extreme Chemical Abundance Ratio Suggesting An Exotic Origin For An Ultradiffuse Galaxy, Ignacio Martín-Navarro, Aaron Romanowsky, Jean Brodie, Anna Ferr´E-Mateu, Adebusola Alabi, Duncan Forbes, Margarita Sharina, Alexa Villaume, Viraj Pandya, David Martinez-Delgado
Faculty Publications
Ultradiffuse galaxies (UDGs) are a population of extended galaxies but with relatively low luminosities. The origin of these objects remains unclear, largely due to the observational challenges of the low surface brightness Universe. We present here a detailed stellar population analysis of a relatively isolated UDG, DGSAT I, based on spectroscopic data from the Keck Cosmic Web Imager integral field unit. The star formation history of DGSAT I seems to be extended, with a mean luminosity-weighted age of ∼3 Gyr, in agreement with previous photometric studies. However, we find a very high [Mg/Fe] abundance ratio, which is extreme even in …
Galaxy And Mass Assembly (Gama): Time-Scales For Galaxies Crossing The Green Valley, S. Phillipps, M. N. Bremer, A. M. Hopkins, R. De Propris, E. N. Taylor, P. A. James, L. J.M. Davies, M. E. Cluver, S. P. Driver, S. A. Eales, Benne W. Holwerda, L. S. Kelvin, A. E. Sansom
Galaxy And Mass Assembly (Gama): Time-Scales For Galaxies Crossing The Green Valley, S. Phillipps, M. N. Bremer, A. M. Hopkins, R. De Propris, E. N. Taylor, P. A. James, L. J.M. Davies, M. E. Cluver, S. P. Driver, S. A. Eales, Benne W. Holwerda, L. S. Kelvin, A. E. Sansom
Faculty Scholarship
We explore the constraints that can be placed on the evolutionary time-scales for typical low-redshift galaxies evolving from the blue cloud through the green valley and on to the red sequence. We utilize galaxies from the GAMA survey with 0.1 < z < 0.2 and classify them according to the intrinsic (u∗ - r∗) colours of their stellar populations, as determined by fits to their multiwavelength spectral energy distributions. Using these fits to also determine stellar population ages and star formation time-scales, we argue that our results are consistent with a green valley population dominated by galaxies that are simply decreasing their star formation (running out of gas) over a time-scale of 2-4 Gyr which are seen at a specific epoch in their evolution (approximately 1.6 e-folding times after their peak in star formation). If their fitted star formation histories are extrapolated forward, the green galaxies will further redden over time, until they attain the colours of a passive population. In this picture, no specific quenching event which cuts-off their star formation is required, though it remains possible that the decline in star formation in green galaxies may be expedited by internal or external forces. However, there is no evidence that green galaxies have recently changed their star formation time-scales relative to their previous longer term star formation histories.
Origins Of Ultradiffuse Galaxies In The Coma Cluster – Ii. Constraints From Their Stellar Populations, Anna Ferre-Mateu, Adebusola Alabi, Duncan Forbes, Aaron Romanowsky, Jean Brodie, Viraj Pandya, Ignacio Mart´In-Navarro, Sabine Bellstedt, Asher Wasserman, Maria Stone, Nobuhiro Okabe
Origins Of Ultradiffuse Galaxies In The Coma Cluster – Ii. Constraints From Their Stellar Populations, Anna Ferre-Mateu, Adebusola Alabi, Duncan Forbes, Aaron Romanowsky, Jean Brodie, Viraj Pandya, Ignacio Mart´In-Navarro, Sabine Bellstedt, Asher Wasserman, Maria Stone, Nobuhiro Okabe
Faculty Publications
In this second paper of the series we study, with new Keck/DEIMOS spectra, the stellar populations of seven spectroscopically confirmed ultradiffuse galaxies (UDGs) in the Coma cluster. We find intermediate to old ages (∼7 Gyr), low metallicities ([Z/H] ∼ −0.7 dex) and mostly supersolar abundance patterns ([Mg/Fe] ∼ 0.13 dex). These properties are similar to those of low-luminosity (dwarf) galaxies inhabiting the same area in the cluster and are mostly consistent with being the continuity of the stellar mass scaling relations of more massive galaxies. These UDGs’ star formation histories imply a relatively recent infall into the Coma cluster, consistent …
Galaxy And Mass Assembly (Gama): Morphological Transformation Of Galaxies Across The Green Valley, M. N. Bremer, S. Phillipps, S. Kelvin, R. De Propris, Rebecca Kennedy, Amanda J. Moffett, S. Bamford, L. J.M. Davies, S. P. Driver, B. Häußler, Benne W. Holwerda, A. Hopkins, P. A. James, J. Liske, S. Percival, N. Taylor
Galaxy And Mass Assembly (Gama): Morphological Transformation Of Galaxies Across The Green Valley, M. N. Bremer, S. Phillipps, S. Kelvin, R. De Propris, Rebecca Kennedy, Amanda J. Moffett, S. Bamford, L. J.M. Davies, S. P. Driver, B. Häußler, Benne W. Holwerda, A. Hopkins, P. A. James, J. Liske, S. Percival, N. Taylor
Faculty Scholarship
We explore constraints on the joint photometric and morphological evolution of typical low redshift galaxies as they move from the blue cloud through the green valley and on to the red sequence. We select Galaxy And Mass Assembly (GAMA) survey galaxies with 10.25 < log(M*/Mo˙) < 10.75 and z < 0.2 classified according to their intrinsic u* - r* colour. From single component Śersic fits, we find that the stellar mass-sensitive K-band profiles of red and green galaxy populations are very similar while g-band profiles indicate more disc-like morphologies for the green galaxies: apparent (optical) morphological differences arise primarily from radial mass-to-light ratio variations. Two-component fits show that most green galaxies have significant bulge and disc components and that the blue to red evolution is driven by colour change in the disc. Together, these strongly suggest that galaxies evolve from blue to red through secular disc fading and that a strong bulge is present prior to any decline in star formation. The relative abundance of the green population implies a typical time-scale for traversing the green valley ~1-2 Gyr and is independent of environment, unlike that of the red and blue populations. While environment likely plays a role in triggering the passage across the green valley, it appears to have little effect on time taken. These results are consistent with a green valley population dominated by (early type) disc galaxies that are insufficiently supplied with gas to maintain previous levels of disc star formation, eventually attaining passive colours. No single event is needed to quench their star formation.
The Stellar Populations Of Two Ultra-Diffuse Galaxies From Optical And Near-Infrared Photometry, Viraj Pandya, Aaron J. Romanowsky, Seppo Laine, Jean Brodie, Benjamin Johnson, William Glaccum, Alexa Villaume, Jean-Charles Cuillandre, Stephen Gwyn, Jessica Krick, Ronald Lasker, Ignacio Martín-Navarro, David Martinez-Delgado, Pieter Van Dokkum
The Stellar Populations Of Two Ultra-Diffuse Galaxies From Optical And Near-Infrared Photometry, Viraj Pandya, Aaron J. Romanowsky, Seppo Laine, Jean Brodie, Benjamin Johnson, William Glaccum, Alexa Villaume, Jean-Charles Cuillandre, Stephen Gwyn, Jessica Krick, Ronald Lasker, Ignacio Martín-Navarro, David Martinez-Delgado, Pieter Van Dokkum
Faculty Publications
We present observational constraints on the stellar populations of two ultra-diffuse galaxies (UDGs) using optical through near-infrared (NIR) spectral energy distribution (SED) fitting. Our analysis is enabled by new Spitzer-IRAC 3.6 and 4.5 μm imaging, archival optical imaging, and the prospectorfully Bayesian SED fitting framework. Our sample contains one field UDG (DGSAT I), one Virgo cluster UDG (VCC 1287), and one Virgo cluster dwarf elliptical for comparison (VCC 1122). We find that the optical–NIR colors of the three galaxies are significantly different from each other. We infer that VCC 1287 has an old (7.7 Gyr) and surprisingly metal-poor …
Galaxy And Mass Assembly (Gama): Blue Spheroids Within 87 Mpc, Smriti Mahajan, Michael J. Drinkwater, S. Driver, A. M. Hopkins, Alister W. Graham, S. Brough, Michael J.I. Brown, Benne W. Holwerda, Matt S. Owers, Kevin A. Pimbblet
Galaxy And Mass Assembly (Gama): Blue Spheroids Within 87 Mpc, Smriti Mahajan, Michael J. Drinkwater, S. Driver, A. M. Hopkins, Alister W. Graham, S. Brough, Michael J.I. Brown, Benne W. Holwerda, Matt S. Owers, Kevin A. Pimbblet
Faculty Scholarship
In this paper, we test if nearby blue spheroid (BSph) galaxies may become the progenitors of star-forming spiral galaxies or passively evolving elliptical galaxies. Our sample comprises 428 galaxies of various morphologies in the redshift range 0.002 < Ζ < 0.02 (8-87 Mpc) with panchromatic data from the Galaxy and Mass Assembly survey. We find that BSph galaxies are structurally (mean effective surface brightness, effective radius) very similar to their passively evolving red counterparts. However, their star formation and other properties such as colour, age, and metallicity are more like star-forming spirals than spheroids (ellipticals and lenticulars). We show that BSph galaxies are statistically distinguishable from other spheroids as well as spirals in the multidimensional space mapped by luminosity-weighted age, metallicity, dust mass, and specific star formation rate. We use HI data to reveal that some of the BSphs are (further) developing their discs, hence their blue colours. They may eventually become spiral galaxies - if sufficient gas accretion occurs - or more likely fade into low-mass red galaxies.
On The Formation Mechanisms Of Compact Elliptical Galaxies, Anna Ferré-Mateu, Duncan Forbes, Aaron Romanowsky, Joachim Janz, Christopher Dixon
On The Formation Mechanisms Of Compact Elliptical Galaxies, Anna Ferré-Mateu, Duncan Forbes, Aaron Romanowsky, Joachim Janz, Christopher Dixon
Faculty Publications
In order to investigate the formation mechanisms of the rare compact elliptical (cE) galaxies, we have compiled a sample of 25 cEs with good SDSS spectra, covering a range of stellar masses, sizes and environments. They have been visually classified according to the interaction with their host, representing different evolutionary stages. We have included clearly disrupted galaxies, galaxies that despite not showing signs of interaction are located close to a massive neighbour (thus are good candidates for a stripping process), and cEs with no host nearby. For the latter, tidal stripping is less likely to have happened and instead they …
Galaxy And Mass Assembly (Gama): The Consistency Of Gama And Wise Derived Mass-To-Light Ratios, T. Kettlety, J. Hesling, S. Phillipps, M. N. Bremer, M. E. Cluver, E. N. Taylor, J. Bland-Hawthorn, S. Brough, R. De Propris, S. P. Driver, Benne W. Holwerda, L. S. Kelvin, W. Sutherland, A. H. Wright
Galaxy And Mass Assembly (Gama): The Consistency Of Gama And Wise Derived Mass-To-Light Ratios, T. Kettlety, J. Hesling, S. Phillipps, M. N. Bremer, M. E. Cluver, E. N. Taylor, J. Bland-Hawthorn, S. Brough, R. De Propris, S. P. Driver, Benne W. Holwerda, L. S. Kelvin, W. Sutherland, A. H. Wright
Faculty Scholarship
Recent work has suggested that mid-IR wavelengths are optimal for estimating the mass-to-light ratios of stellar populations and hence the stellar masses of galaxies. We compare stellar masses deduced from spectral energy distribution (SED) models, fitted to multiwavelength optical-NIR photometry, to luminosities derived from WISE photometry in the W1 and W2 bands at 3.6 and 4.5 μmfor non-star forming galaxies. The SED-derived masses for a carefully selected sample of low-redshift (z≤0.15) passive galaxies agree with the prediction from stellar population synthesis models such that M*/LW1 ≃0.6 for all such galaxies, independent of other stellar population parameters. The small scatter between …
Initial Mass Function Variability (Or Not) Among Low-Velocity Dispersion, Compact Stellar Systems, Alexa Villaume, Jean Brodie, Charlie Conroy, Aaron Romanowsky, Pieter Van Dokkum
Initial Mass Function Variability (Or Not) Among Low-Velocity Dispersion, Compact Stellar Systems, Alexa Villaume, Jean Brodie, Charlie Conroy, Aaron Romanowsky, Pieter Van Dokkum
Faculty Publications
Analyses of strong gravitational lenses, galaxy-scale kinematics, and absorption-line stellar population synthesis (SPS) have all concluded that the stellar initial mass function (IMF) varies within the massive early-type galaxy (ETG) population. However, the physical mechanism that drives variation in the IMF is an outstanding question. Here we use new SPS models to consider a diverse set of compact, low-velocity dispersion stellar systems: globular clusters (GCs), an ultra-compact dwarf (UCD), and the compact elliptical (cE) galaxy M32. We compare our results to massive ETGs and available dynamical measurements. We find that the GCs have stellar mass-to-light ratios (M/L) that are either …
The Stellar Initial Mass Function In Early-Type Galaxies From Absorption Line Spectroscopy. Iii. Radial Gradients, Pieter Van Dokkum, Charlie Conroy, Alexa Villaume, Jean Brodie, Aaron Romanowsky
The Stellar Initial Mass Function In Early-Type Galaxies From Absorption Line Spectroscopy. Iii. Radial Gradients, Pieter Van Dokkum, Charlie Conroy, Alexa Villaume, Jean Brodie, Aaron Romanowsky
Faculty Research, Scholarly, and Creative Activity
No abstract provided.
The Ghosts Survey. I. Hubble Space Telescope Advanced Camera For Surveys Data., D. J. Radburn-Smith, R. S. De Jong, A. C. Seth, J. Bailin, E. F. Bell, T. M. Brown, J. S. Bullock, S. Courteau, J. J. Dalcanton, H. C. Ferguson, P. Goudfrooij, S. Holfeltz, Benne W. Holwerda, C. Purcell, J. Sick, D. Streich, M. Vlajic, D. B. Zucker
The Ghosts Survey. I. Hubble Space Telescope Advanced Camera For Surveys Data., D. J. Radburn-Smith, R. S. De Jong, A. C. Seth, J. Bailin, E. F. Bell, T. M. Brown, J. S. Bullock, S. Courteau, J. J. Dalcanton, H. C. Ferguson, P. Goudfrooij, S. Holfeltz, Benne W. Holwerda, C. Purcell, J. Sick, D. Streich, M. Vlajic, D. B. Zucker
Benne Holwerda
We present an overview of the GHOSTS survey, the largest study to date of the resolved stellar populations in the outskirts of disk galaxies. The sample consists of 14 disk galaxies within 17 Mpc, whose outer disks and halos are imaged with the Hubble Space Telescope Advanced Camera for Surveys (ACS). In the first paper of this series, we describe the sample, explore the benefits of using resolved stellar populations, and discuss our ACS F606W and F814W photometry. We use artificial star tests to assess completeness and use overlapping regions to estimate photometric uncertainties. The median depth of the survey …
The S4g Perspective On Circumstellar Dust Extinction Of Asymptotic Giant Branch Stars In M100., Sharon Meidt, Eva Schinnerer, Juan Carlos Munoz-Mateos, Benne W. Holwerda, Luis C. Ho, Barry F. Madore, Johan H. Knapen, Albert Bosma, E. Athanassoula, Joannah L. Hinz, Kartik Sheth, Michael Regan, Armando Gil De Paz, Karin Menendez-Delmestre, Mark Seibert, Taehyun Kim, Trisha Mizusawa, Dimitri A. Gadotti, Eija Laurikainen, Heikki Salo, Jarkko Laine, Sebastien Comeron
The S4g Perspective On Circumstellar Dust Extinction Of Asymptotic Giant Branch Stars In M100., Sharon Meidt, Eva Schinnerer, Juan Carlos Munoz-Mateos, Benne W. Holwerda, Luis C. Ho, Barry F. Madore, Johan H. Knapen, Albert Bosma, E. Athanassoula, Joannah L. Hinz, Kartik Sheth, Michael Regan, Armando Gil De Paz, Karin Menendez-Delmestre, Mark Seibert, Taehyun Kim, Trisha Mizusawa, Dimitri A. Gadotti, Eija Laurikainen, Heikki Salo, Jarkko Laine, Sebastien Comeron
Benne Holwerda
We examine the effect of circumstellar dust extinction on the near-IR (NIR) contribution of asymptotic giant branch (AGB) stars in intermediate-age clusters throughout the disk of M100. For our sample of 17 AGB-dominated clusters we extract optical-to-mid-IR spectral energy distributions (SEDs) and find that NIR brightness is coupled to the mid-IR dust emission in such a way that a significant reduction of AGB light, of up to 1 mag in the K band, follows from extinction by the dust shell formed during this stage. Since the dust optical depth varies with AGB chemistry (C-rich or O-rich), our results suggest that …
Outer-Disk Populations In Ngc 7793 : Evidence For Stellar Radial Migration., David J. Radburn-Smith, Rok Roskar, Victor P. Debattista, Julianne J. Dalcanton, David Streich, Roelof S. De Jong, Marija Vlajic, Benne W. Holwerda, Chris W. Purcell, Andrew E. Dolphin, Daniel B. Zucker
Outer-Disk Populations In Ngc 7793 : Evidence For Stellar Radial Migration., David J. Radburn-Smith, Rok Roskar, Victor P. Debattista, Julianne J. Dalcanton, David Streich, Roelof S. De Jong, Marija Vlajic, Benne W. Holwerda, Chris W. Purcell, Andrew E. Dolphin, Daniel B. Zucker
Benne Holwerda
We analyzed the radial surface brightness profile of the spiral galaxy NGC 7793 using HST/ACS images from the GHOSTS survey and a new HST/WFC3 image across the disk break. We used the photometry of resolved stars to select distinct populations covering a wide range of stellar ages. We found breaks in the radial profiles of all stellar populations at 280 (∼5.1 kpc). Beyond this disk break, the profiles become steeper for younger populations. This same trend is seen in numerical simulations where the outer disk is formed almost entirely by radial migration. We also found that the older stars of …
Testing Galaxy Formation Models With The Ghosts Survey : The Color Profile Of M81'S Stellar Halo., Antonela Monachesi, Eric F. Bell, David J. Radburn-Smith, Marija Vlajic, Roelof S. De Jong, Jeremy Bailin, Julianne J. Dalcanton, Benne W. Holwerda, David Streich
Testing Galaxy Formation Models With The Ghosts Survey : The Color Profile Of M81'S Stellar Halo., Antonela Monachesi, Eric F. Bell, David J. Radburn-Smith, Marija Vlajic, Roelof S. De Jong, Jeremy Bailin, Julianne J. Dalcanton, Benne W. Holwerda, David Streich
Benne Holwerda
We study the properties of the stellar populations in M81’s outermost part, which hereafter we will call the stellar halo, using Hubble Space Telescope (HST) Advanced Camera for Surveys observations of 19 fields from the GHOSTS survey. The observed fields probe the stellar halo out to a projected distance of ∼50 kpc from the galactic center. Each field was observed in both F606W and F814W filters. The 50% completeness levels of the color–magnitude diagrams (CMDs) are typically at 2 mag below the tip of the red giant branch (TRGB). Fields at distances closer than 15 kpc show evidence of disk-dominated …
The Impact Of Bars On Disk Breaks As Probed By S4g Imaging., Juan Carlos Munoz-Mateos, Kartik Sheth, Armando Gil De Paz, Sharon Meidt, E. Athanassoula, Albert Bosma, Sebastien Comeron, Debra M. Elmegreen, Bruce G. Elmegreen, Santiago Erroz-Ferrer, Dimitri A. Gadotti, Joannah L. Hinz, Luis C. Ho, Benne W. Holwerda, Thomas H. Jarrett, Taehyun Kim, Johan H. Knapen, Jarkko Laine, Eija Laurikainen, Barry F. Madore, Karin Menendez-Delmestre, Trisha Mizusawa, Michael Regan, Heikki Salo, Eva Schinnerer, Mark Seibert, Ramin Skibba, Dennis Zaritsky
The Impact Of Bars On Disk Breaks As Probed By S4g Imaging., Juan Carlos Munoz-Mateos, Kartik Sheth, Armando Gil De Paz, Sharon Meidt, E. Athanassoula, Albert Bosma, Sebastien Comeron, Debra M. Elmegreen, Bruce G. Elmegreen, Santiago Erroz-Ferrer, Dimitri A. Gadotti, Joannah L. Hinz, Luis C. Ho, Benne W. Holwerda, Thomas H. Jarrett, Taehyun Kim, Johan H. Knapen, Jarkko Laine, Eija Laurikainen, Barry F. Madore, Karin Menendez-Delmestre, Trisha Mizusawa, Michael Regan, Heikki Salo, Eva Schinnerer, Mark Seibert, Ramin Skibba, Dennis Zaritsky
Benne Holwerda
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 …
Constraining The Age Of The Ngc 4565 Hi Disk Warp : Determining The Origin Of Gas Warps., David J. Radburn-Smith, Roelof S. De Jong, David Streich, Eric F. Bell, Julianne J. Dalcanton, Andrew E. Dolphin, Adrienne M. Stilp, Antonela Monachesi, Benne W. Holwerda, Jeremy Bailin
Constraining The Age Of The Ngc 4565 Hi Disk Warp : Determining The Origin Of Gas Warps., David J. Radburn-Smith, Roelof S. De Jong, David Streich, Eric F. Bell, Julianne J. Dalcanton, Andrew E. Dolphin, Adrienne M. Stilp, Antonela Monachesi, Benne W. Holwerda, Jeremy Bailin
Benne Holwerda
We have mapped the distribution of young and old stars in the gaseous H i warp of NGC 4565. We find a clear correlation of young stars (< 600 Myr) with the warp but no coincident old stars (> 1 Gyr), which places an upper limit on the age of the structure. The formation rate of the young stars, which increased ∼ 300 Myr ago relative to the surrounding regions, is (6.3+2.5 −1.5) × 10−5 M yr−1 kpc−2. This implies a ∼ 60 ± 20 Gyr depletion time of the H i warp, similar to the timescales calculated for the outer H i disks of nearby spiral galaxies. While some stars …
Morphological Parameters Of A Spitzer Survey Of Stellar Structure In Galaxies., Benne W. Holwerda, J. C. Munoz-Mateos, S. Comeron, S. Meidt, K. Sheth, S. Laine, J. L. Hinz, M. W. Regan, A. Gil De Paz, K. Menendez-Delmestre, M. Seibert, T. Kim, T. Mizusawa, E. Laurikainen, H. Salo, J. Laine, D. A. Gadotti, D. Zaritsky, S. Erroz-Ferrer, L. C. Ho, J. H. Knapen, E. Athanassoula, A. Bosma, N. Pirzkal
Morphological Parameters Of A Spitzer Survey Of Stellar Structure In Galaxies., Benne W. Holwerda, J. C. Munoz-Mateos, S. Comeron, S. Meidt, K. Sheth, S. Laine, J. L. Hinz, M. W. Regan, A. Gil De Paz, K. Menendez-Delmestre, M. Seibert, T. Kim, T. Mizusawa, E. Laurikainen, H. Salo, J. Laine, D. A. Gadotti, D. Zaritsky, S. Erroz-Ferrer, L. C. Ho, J. H. Knapen, E. Athanassoula, A. Bosma, N. Pirzkal
Benne Holwerda
The morphology of galaxies can be quantified to some degree using a set of scale-invariant parameters. Concentration (C), asymmetry (A), smoothness (S), the Gini index (G), the relative contribution of the brightest pixels to the secondorder moment of the flux (M20), ellipticity (E), and the Gini index of the second-order moment (GM) have all been applied to morphologically classify galaxies at various wavelengths. Here, we present a catalog of these parameters for the Spitzer Survey of stellar structure in Galaxies, a volume-limited, near-infrared (NIR) imaging survey of nearby galaxies using the 3.6 and 4.5μm channels of the Infrared Array Camera …
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 Meidt, Eva Schinnerer, Glenn Van De Ven, Dennis Zaritsky, Reynier Peletier, Johan H. Knapen, Kartik Sheth, Michael Regan, Miguel Querejeta, Juan Carlos Munoz-Mateos, Taehyun Kim, Joannah Hinz, Armando Gil De Paz, E. Athanassoula, Albert Bosma, Ronald J. Buta, Mauricio Cisternas, Luis C. Ho, Benne W. Holwerda, Ramin Skibba, E. Laurikainen, H. Salo, D. A. Gadotti, Jarkko Laine, Santiago Erroz-Ferrer, Sebastien Comeron, K. Menendez-Delmestre, M. Seibert, T. 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 Meidt, Eva Schinnerer, Glenn Van De Ven, Dennis Zaritsky, Reynier Peletier, Johan H. Knapen, Kartik Sheth, Michael Regan, Miguel Querejeta, Juan Carlos Munoz-Mateos, Taehyun Kim, Joannah Hinz, Armando Gil De Paz, E. Athanassoula, Albert Bosma, Ronald J. Buta, Mauricio Cisternas, Luis C. Ho, Benne W. Holwerda, Ramin Skibba, E. Laurikainen, H. Salo, D. A. Gadotti, Jarkko Laine, Santiago Erroz-Ferrer, Sebastien Comeron, K. Menendez-Delmestre, M. Seibert, T. Mizusawa
Benne Holwerda
We present a new approach for estimating the 3.6μm 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 avoid the …
Galaxy And Mass Assembly (Gama) : Mid-Infrared Properties And Empirical Relations From Wise., M. E. Cluver, T. H. Jarrett, A. M. Hopkins, S. P. Driver, J. Liske, M. L. P. Gunawardhana, E. N. Taylor, A. S. G. Robotham, M. Alpaslan, I. Baldry, M. J. I. Brown, J. A. Peacock, C. C. Popescu, R. J. Tuffs, A. E. Bauer, J. Bland-Hawthorn, M. Colless, Benne W. Holwerda, M. A. Lara-Lopez, K. Leschinski, A. R. Lopez-Sanchez, P. Norberg, M. S. Owers, L. Wang, S. M. Wilkins
Galaxy And Mass Assembly (Gama) : Mid-Infrared Properties And Empirical Relations From Wise., M. E. Cluver, T. H. Jarrett, A. M. Hopkins, S. P. Driver, J. Liske, M. L. P. Gunawardhana, E. N. Taylor, A. S. G. Robotham, M. Alpaslan, I. Baldry, M. J. I. Brown, J. A. Peacock, C. C. Popescu, R. J. Tuffs, A. E. Bauer, J. Bland-Hawthorn, M. Colless, Benne W. Holwerda, M. A. Lara-Lopez, K. Leschinski, A. R. Lopez-Sanchez, P. Norberg, M. S. Owers, L. Wang, S. M. Wilkins
Benne Holwerda
The Galaxy And Mass Assembly (GAMA) survey furnishes a deep redshift catalog that, when combined with the Wide-field Infrared Survey Explorer (WISE), allows us to explore for the first time the mid-infrared properties of >110,000 galaxies over 120 deg2 to z 0.5. In this paper we detail the procedure for producing the matched GAMA-WISE catalog for the G12 and G15 fields, in particular characterizing and measuring resolved sources; the complete catalogs for all three GAMA equatorial fields will be made available through the GAMA public releases. The wealth of multiwavelength photometry and optical spectroscopy allows us to explore empirical relations …
The Baryonic Tully-Fisher Relationship For S4g Galaxies And The "Condensed" Baryon Fraction Of Galaxies., Dennis Zaritsky, Helene M. Courtois, Juan Carlos Munoz-Mateos, Jenny Sorce, S. Erroz-Ferrer, S. Comeron, D. A. Gadotti, A. Gil De Paz, J. L. Hinz, E. Laurikainen, T. Kim, J. Laine, K. Menendez-Delmestre, T. Mizusawa, M. W. Regan, H. Salo, M. Seibert, K. Sheth, E. Athanassoula, A. Bosma, M. Cisternas, Luis C. Ho, Benne W. Holwerda
The Baryonic Tully-Fisher Relationship For S4g Galaxies And The "Condensed" Baryon Fraction Of Galaxies., Dennis Zaritsky, Helene M. Courtois, Juan Carlos Munoz-Mateos, Jenny Sorce, S. Erroz-Ferrer, S. Comeron, D. A. Gadotti, A. Gil De Paz, J. L. Hinz, E. Laurikainen, T. Kim, J. Laine, K. Menendez-Delmestre, T. Mizusawa, M. W. Regan, H. Salo, M. Seibert, K. Sheth, E. Athanassoula, A. Bosma, M. Cisternas, Luis C. Ho, Benne W. Holwerda
Benne Holwerda
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 …
Galaxy And Mass Assembly (Gama) : Galaxy Close Pairs, Mergers And The Future Fate Of Stellar Mass., A. S. G. Robotham, S. P. Driver, L. J. M. Davies, A. M. Hopkins, I. K. Baldry, N. K. Agius, A. E. Bauer, J. Bland-Hawthorn, S. Brough, M. J. I. Brown, M. Cluver, R. De Propis, M. J. Drinkwater, Benne W. Holwerda, L. S. Kelvin, M. A. Lara-Lopez, J. Liske, Angel R. Lopez-Sanchez, J. Loveday, S. Mahajan, T. Mcnaught-Roberts, A. Moffett, P. Norberg, D. Obreschkow, M. S. Owers, S. J. Penny, K. A. Pimbblet, M. Prescott, E. N. Taylor, E. Van Kampen, S. M. Wilkins
Galaxy And Mass Assembly (Gama) : Galaxy Close Pairs, Mergers And The Future Fate Of Stellar Mass., A. S. G. Robotham, S. P. Driver, L. J. M. Davies, A. M. Hopkins, I. K. Baldry, N. K. Agius, A. E. Bauer, J. Bland-Hawthorn, S. Brough, M. J. I. Brown, M. Cluver, R. De Propis, M. J. Drinkwater, Benne W. Holwerda, L. S. Kelvin, M. A. Lara-Lopez, J. Liske, Angel R. Lopez-Sanchez, J. Loveday, S. Mahajan, T. Mcnaught-Roberts, A. Moffett, P. Norberg, D. Obreschkow, M. S. Owers, S. J. Penny, K. A. Pimbblet, M. Prescott, E. N. Taylor, E. Van Kampen, S. M. Wilkins
Benne Holwerda
We use a highly complete subset of the Galaxy And Mass Assembly II (GAMA-II) redshift sample to fully describe the stellar mass dependence of close pairs and mergers between 108 and 1012 M⊙. Using the analytic form of this fit we investigate the total stellar mass accreting on to more massive galaxies across all mass ratios. Depending on how conservatively we select our robust merging systems, the fraction of mass merging on to more massive companions is 2.0–5.6 per cent. Using the GAMA-II data we see no significant evidence for a change in the close pair fraction between redshift z …
Extragalactic Archeology With The Ghosts Survey : I. Age-Resolved Disk Structure Of Nearby Low-Mass Galaxies., David Streich, Roelof S. De Jong, Jeremy Bailin, Eric F. Bell, Benne W. Holwerda, Ivan Minchev, Antonela Monachesi, David J. Radburn-Smith
Extragalactic Archeology With The Ghosts Survey : I. Age-Resolved Disk Structure Of Nearby Low-Mass Galaxies., David Streich, Roelof S. De Jong, Jeremy Bailin, Eric F. Bell, Benne W. Holwerda, Ivan Minchev, Antonela Monachesi, David J. Radburn-Smith
Benne Holwerda
Aims. We study the individual evolution histories of three nearby low-mass edge-on galaxies (IC 5052, NGC 4244, and NGC 5023). Methods. Using resolved stellar populations, we constructed star count density maps for populations of different ages and analyzed the change of structural parameters with stellar age within each galaxy. Results. We do not detect a separate thick disk in any of the three galaxies, even though our observations cover a wider range in equivalent surface brightness than any integrated light study. While scale heights increase with age, each population can be well described by a single disk. Two of the …
Globular Cluster Populations : Results Including S4g Late-Type Galaxies., Dennis Zaritsky, Kelsey Mccabe, Manuel Aravena, E. Athanassoula, Albert Bosma, Sebastien Comeron, Helene M. Courtois, Bruce G. Elmegreen, Debra M. Elmegreen, Santiago Erroz-Ferrer, Dimitri A. Gadotti, Joannah L. Hinz, Luis C. Ho, Benne W. Holwerda, Taehyun Kim, Johan H. Knapen, Jarkko Laine, Eija Laurikainen, Juan Carlos Muñoz-Mateos, Heikki Salo, Kartik Sheth
Globular Cluster Populations : Results Including S4g Late-Type Galaxies., Dennis Zaritsky, Kelsey Mccabe, Manuel Aravena, E. Athanassoula, Albert Bosma, Sebastien Comeron, Helene M. Courtois, Bruce G. Elmegreen, Debra M. Elmegreen, Santiago Erroz-Ferrer, Dimitri A. Gadotti, Joannah L. Hinz, Luis C. Ho, Benne W. Holwerda, Taehyun Kim, Johan H. Knapen, Jarkko Laine, Eija Laurikainen, Juan Carlos Muñoz-Mateos, Heikki Salo, Kartik Sheth
Benne Holwerda
Using 3.6 and 4.5 μm images of 73 late-type, edge-on galaxies from the S4 G survey, we compare the richness of the globular cluster populations of these galaxies to those of early-type galaxies that we measured previously. In general, the galaxies presented here fill in the distribution for galaxies with lower stellar mass, M*, specifically log 10 ( ) M M * < , overlap the results for early-type galaxies of similar masses, and, by doing so, strengthen the case for a dependence of the number of globular clusters per 109 Me of galaxy stellar mass, TN, on M*. For …