Astrophysics and Astronomy Commons^™

The Size And Shape Of The Milky Way Disc And Halo From M-Type Brown Dwarfs In The Borg Survey., Isabel Van Vledder, Dieuwertje Van Der Vlugt, Benne W. Holwerda, M. A. Kenworthy, R. J. Bouwens, M. Trenti

Faculty and Staff Scholarship

We have identified 274 M-type brown dwarfs in the Hubble Space Telescope's Wide Field Camera 3 pure parallel fields from the Brightest of Reionizing Galaxies (BoRG) survey for high-redshift galaxies. These are near-infrared observations with multiple lines of sight out of our Milky Way. Using these observed M-type brown dwarfs, we fitted a Galactic disc and halo model with a Markov chain Monte Carlo analysis. This model worked best with the scalelength of the disc fixed at h = 2.6 kpc. For the scaleheight of the disc, we found z0=0.29+0.02−0.019 z0=0.29−0.019+0.02 kpc and for the central number density, ρ0=0.29+0.20−0.13 ρ0=0.29−0.13+0.20 …

Galaxy And Mass Assembly (Gama): Stellar Mass Growth Of Spiral Galaxies In The Cosmic Web., Mehmet Alpaslan, Meiert Grootes, Pamela M. Marcum, Cristina C. Popescu, Richard Tuffs, Joss Bland-Hawthorn, Sarah Brough, Michael J. I. Brown, Luke J. M. Davies, Simon P. Driver, Benne W. Holwerda, Lee S. Kelvin, Maritza A. Lara-Lopez, Angel R. Lopez-Sanchez, Jon Loveday, Amanda J. Moffett, Edward N. Taylor, Matt S. Owers, Aaron S. G. Robotham

Faculty and Staff Scholarship

We look for correlated changes in stellar mass and star formation rate (SFR) along filaments in the cosmic web by examining the stellar masses and UV-derived SFRs of 1799 ungrouped and unpaired spiral galaxies that reside in filaments. We devise multiple distance metrics to characterize the complex geometry of filaments, and find that galaxies closer to the cylindrical centre of a filament have higher stellar masses than their counterparts near the periphery of filaments, on the edges of voids. In addition, these peripheral spiral galaxies have higher SFRs at a given mass. Complementing our sample of filament spiral galaxies with …

The Ghosts Survey – Ii. The Diversity Of Halo Colour And Metallicity Profiles Of Massive Disc Galaxies., Antonela Monachesi, Eric F. Bell, David J. Radburn-Smith, Jeremy Bailin, Roelof S. De Jong, Benne W. Holwerda, David Streich, Grace Silverstein

Faculty and Staff Scholarship

We study the stellar halo colour properties of six nearby massive highly inclined disc galaxies using Hubble space telescope Advanced Camera for Surveys and Wide Field Camera 3 observations in both F606W and F814W filters from the GHOSTS (Galaxy Halos, Outer disks, Substructure, Thick disks, and Star clusters) survey. The observed fields probe the stellar outskirts out to projected distances of ∼50–70 kpc from their galactic centre along the minor axis. The 50 per cent completeness levels of the colour–magnitude diagrams are typically at 2 mag below the tip of the red giant branch (RGB). We …

Galaxy And Mass Assembly (Gama) : The Stellar Mass Budget By Galaxy Type., Amanda J. Moffett, Stephen A. Ingarfield, Simon P. Driver, Aaron S. G. Robotham, Lee S. Kelvin, Rebecca Lange, Uros Mestric, Mehmet Alpaslan, Ivan K. Baldry, Joss Bland-Hawthorn, Sarah Brough, Michelle Cluver, Luke J. M. Davies, Benne W. Holwerda, Andrew M. Hopkins, Prajwal R. Kafle, Rebecca Kennedy, Peder Norberg, Edward N. Taylor

Faculty and Staff Scholarship

We report an expanded sample of visual morphological classifications from the Galaxy and Mass Assembly survey phase two, which now includes 7556 objects (previously 3727 in phase one). We define a local (z < 0.06) sample and classify galaxies into E, S0-Sa, SB0-SBa, Sab-Scd, SBab-SBcd, Sd-Irr, and ‘little blue spheroid’ types. Using these updated classifications, we derive stellar mass function fits to individual galaxy populations divided both by morphological class and more general spheroid- or disc-dominated categories with a lower mass limit of log(M*/M⊙) = 8 (one dex below earlier morphological mass function determinations). We find that all individual morphological classes and the combined spheroid-/bulge-dominated classes are well described by single Schechter stellar mass function forms. We find that the total stellar mass densities for individual galaxy populations and for the entire galaxy population are bounded within our stellar mass limits and derive an estimated total stellar mass …

Erratum : "The Impact Of Bars On Disk Breaks As Probed By S4g Imaging"., Juan Carlos Muñoz-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, Michael Seibert, Ramin Skibba, Dennis Zaritsky

Faculty and Staff Scholarship

No abstract provided.

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

Faculty and Staff Scholarship

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 8.5 log 10.5 ( ) M M * < <  we find the relationship can be satisfactorily described as T M N 106.7 0.56 ( ) * = - when M* is expressed in solar masses. The functional form of the relationship is only weakly constrained, and extrapolation outside this range is not advised. Our late-type galaxies, in contrast to our early types, do not show the tendency for low-mass galaxies to split into two TN families. Using these results and a galaxy stellar mass function from the literature, we calculate that, in a volume-limited, local universe sample, clusters are most likely to be found around fairly massive galaxies (M* ∼ 1010.8Me) and present a fitting function for the volume number density of clusters as a function of parent-galaxy stellar mass. We find no correlation between TN and large-scale environment, but we do find a tendency for galaxies of fixed M* to have larger TN if they have converted a larger proportion of their baryons into stars.

Galaxy And Mass Assembly (Gama) : Panchromatic Data Release (Far-Uv–Far-Ir) And The Low-Z Energy Budget., Simon P. Driver, Angus H. Wright, Stephen K. Andrews, Luke J. M. Davies, Prajwal R. Kafle, Rebecca Lange, Amanda J. Moffett, Elizabeth Mannering, Aaron S. G. Robotham, Kevin Vinsen, Mehmet Alpaslan, Ellen Andrae, Ivan K. Baldry, Amanda E. Bauer, Steven P. Bamford, Joss Bland-Hawthorn, Nathan Bourne, Sarah Brough, Michael J. I. Brown, Michelle Cluver, Scott M. Croom, Matthew Colless, Christopher J. Conselice, Elisabete Da Cunha, Roberto De Propris, Michael Drinkwater, Loretta Dunne, Steve Eales, Alastair Edge, Carlos Frenk, Alister W. Graham, Meiert Grootes, Benne W. Holwerda, Andrew M. Hopkins, Edo Ibar, Eelco Van Kampen, Lee S. Kelvin, Tom Jarrett, D. Heath Jones, Maritza A. Lara-Lopez, Jochen Liske, Angel R. Lopez-Sanchez, Jon Loveday, Steve J. Maddox, Barry Madore, Smriti Mahajan, Martin Meyer, Peder Norberg, Samantha J. Penny, Steven Phillipps, Cristina C. Popescu, Richard Tuffs, John A. Peacock, Kevin A. Pimbblet, Matthew Prescott, Kate Rowlands, Anne E. Sansom, Mark Seibert, Matthew W. L. Smith, Will J. Sutherland, Edward N. Taylor, Elisabetta Valiante, J. Antonio Vazquez-Mata, Lingyu Wang, Stephen M. Wilkins, Richard P. Williams

Faculty and Staff Scholarship

We present the Galaxy And Mass Assembly (GAMA) Panchromatic Data Release (PDR) constituting over 230 deg2 of imaging with photometry in 21 bands extending from the far-UV to the far-IR. These data complement our spectroscopic campaign of over 300k galaxies, and are compiled from observations with a variety of facilities including: GALaxy Evolution eXplorer, Sloan Digital Sky Survey, Visible and Infrared Telescope for Astronomy (VISTA), Wide-field Infrared Survey Explorer, and Herschel, with the GAMA regions currently being surveyed by VLT Survey Telescope (VST) and scheduled for observations by Australian Square Kilometer Array Pathfinder (ASKAP). These data are processed to a …

Galaxy And Mass Assembly (Gama) : Growing Up In A Bad Neighbourhood – How Do Low-Mass Galaxies Become Passive?, L. J. M. Davies, A. S. G. Robotham, S. P. Driver, M. Alpaslan, I. K. Baldry, J. Bland-Hawthorn, S. Brough, M. J. I. Brown, M. E. Cluver, Benne W. Holwerda, A. M. Hopkins, M. A. Lara-Lopez, S. Mahajan, A. J. Moffett, M. S. Owers, S. Phillipps

Faculty and Staff Scholarship

Both theoretical predictions and observations of the very nearby Universe suggest that low-mass galaxies(log10[M*/M⊙] < 9.5) are likely to remain star-forming unless they are affected by their local environment. To test this premise, we compare and contrast the local environment of both passive and star-forming galaxies as a function of stellar mass, using the Galaxy and Mass Assembly survey. We find that passive fractions are higher in both interacting pair and group galaxies than the field at all stellar masses, and that this effect is most apparent in the lowest mass galaxies. We also find that essentially all passive log10[M*/M⊙] < 8.5 galaxies are found in pair/group environments, suggesting that local interactions with a more massive neighbour cause them to cease forming new stars. We find that the effects of immediate environment (local galaxy–galaxy interactions) in forming passive systems increase with decreasing stellar mass, and highlight that this is potentially due to increasing interaction time-scales giving sufficient time for the galaxy to become passive via starvation. We then present a simplistic model to test this premise, and show that given our speculative assumptions, it is consistent with our observed results.

Bright Galaxies At Hubble's Redshift Detection Frontier : Preliminary Results And Design From The Redshift Z ~ 9-10 Borg Pure-Parallel Hst Survey., V. Calvi, M. Trenti, M. Stiavelli, P. A. Oesch, L. Bradley, K. B. Schmidt, D. Coe, G. Brammer, S. Bernard, R. J. Bouwens, D. Carrasco, C. M. Carollo, Benne W. Holwerda, J. W. Mackenty, C. A. Mason, J. M. Shull, T. Treu

Faculty and Staff Scholarship

We present the first results and design from the redshift z ∼ 9–10 Brightest of the Reionizing Galaxies Hubble Space Telescope survey BoRG[z9–10], aimed at searching for intrinsically luminous unlensed galaxies during the first 700 Myr after the Big Bang. BoRG[z9–10] is the continuation of a multi-year pure-parallel near-IR and optical imaging campaign with the Wide Field Camera 3. The ongoing survey uses five filters, optimized for detecting the most distant objects and offering continuous wavelength coverage from λ = 0.35 μm to λ = 1.7 μm. We analyze the initial ∼130 arcmin2 of area over 28 independent lines of …

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

Faculty and Staff Scholarship

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 …

Galaxy And Mass Assembly (Gama) : The Wavelength Dependence Of Galaxy Structure Versus Redshift And Luminosity., Rebecca Kennedy, Steven P. Bamford, Ivan K. Baldry, Boris Haußler, Benne W. Holwerda, Andrew M. Hopkins, Lee S. Kelvin, Rebecca Lange, Amanda J. Moffett, Cristina C. Popescu, Edward N. Taylor, Richard Tuffs, Marina Vika, Benedetta Vulcani

Faculty and Staff Scholarship

We study how the sizes and radial profiles of galaxies vary with wavelength, by fitting Sersic ´ functions simultaneously to imaging in nine optical and near-infrared bands. To quantify the wavelength dependence of effective radius we use the ratio, R, of measurements in two rest-frame bands. The dependence of Sersic index on wavelength, ´ N , is computed correspondingly. Vulcani et al. have demonstrated that different galaxy populations present sharply contrasting behaviour in terms of R and N . Here we study the luminosity dependence of this result. We find that at higher luminosities, early-type galaxies display a more substantial …

Galaxy And Mass Assembly (Gama) : The Bright Void Galaxy Population In The Optical And Mid-Ir., S. J. Penny, M. J. I. Brown, K. A. Pimbblet, M. E. Cluver, D. J. Croton, M. S. Owers, R. Lange, M. Alpaslan, I. K. Baldry, J. Bland-Hawthorn, S. Brough, S. P. Driver, Benne W. Holwerda, A. M. Hopkins, T. H. Jarrett, D. Heath Jones, L. S. Kelvin, M. A. Lara-Lopez, J. Liske, Angel R. Lopez-Sanchez, J. Loveday, M. Meyer, P. Norberg, A. S. G. Robotham, M. Rodrigues

Faculty and Staff Scholarship

We examine the properties of galaxies in the Galaxies and Mass Assembly (GAMA) survey located in voids with radii >10 h−1 Mpc. Utilizing the GAMA equatorial survey, 592 void galaxies are identified out to z ≈ 0.1 brighter than Mr = −18.4, our magnitude completeness limit. Using the WHα versus [N ii]/Hα (WHAN) line strength diagnostic diagram, we classify their spectra as star forming, AGN, or dominated by old stellar populations. For objects more massive than 5 × 109 M⊙, we identify a sample of 26 void galaxies with old stellar populations classed as passive and retired …

Herschel Observations Of Edge-On Spirals (Heroes) : Ii. Tilted-Ring Modelling Of The Atomic Gas Disks., F. Allaert, G. Gentile, M. Baes, G. De Geyter, T. M. Hughes, F. Lewis, S. Bianchi, I. De Looze, J. Fritz, Benne W. Holwerda, J. Verstappen, S. Viaene

Faculty and Staff Scholarship

Context. Edge-on galaxies can offer important insight into galaxy evolution because they are the only systems where the distribution of the different components can be studied both radially and vertically. The HEROES project was designed to investigate the interplay between the gas, dust, stars, and dark matter (DM) in a sample of 7 massive edge-on spiral galaxies. Aims. In this second HEROES paper, we present an analysis of the atomic gas content of 6 out of 7 galaxies in our sample. The remaining galaxy was recently analysed according to the same strategy. The primary aim of this work is to …

Reionization After Planck : The Derived Growth Of The Cosmic Ionizing Emissivity Now Matches The Growth Of The Galaxy Uv Luminosity Density., R. J. Bouwens, G. D. Illingworth, P. A. Oesch, J. Caruana, Benne W. Holwerda, R. Smit, S. M. Wilkins

Faculty and Staff Scholarship

Thomson optical depth τ measurements from Planck provide new insights into the reionization of the universe. In pursuit of model-independent constraints on the properties of the ionizing sources, we determine the empirical evolution of the cosmic ionizing emissivity. We use a simple two-parameter model to map out the evolution in the emissivity at z  6 from the new Planck optical depth τ measurements, from the constraints provided by quasar absorption spectra and from the prevalence of Lyα emission in z ∼ 7–8 galaxies. We find the redshift evolution in the emissivity Nion z ˙ ( ) required by the …

Galaxy And Mass Assembly (Gama) : End Of Survey Report And Data Release 2., J. Liske, I. K. Baldry, S. P. Driver, R. J. Tuffs, M. Alpaslan, E. Andrae, S. Brough, M. E. Cluver, M. W. Grootes, M. L. P. Gunawardhana, L. S. Kelvin, J. Loveday, A. S. G. Robotham, E. N. Taylor, S. P. Bamford, J. Bland-Hawthorn, M. J. I. Brown, M. J. Drinkwater, A. M. Hopkins, M. Meyer, P. Norberg, J. A. Peacock, N. K. Agius, S. K. Andrews, A. E. Bauer, J. H. Y. Ching, M. Colless, C. J. Conselice, S. M. Croom, L. J. M. Davies, R. De Propris, L. Dunne, E. M. Eardley, S. Ellis, C. Foster, C. S. Frenk, B. Haußler, Benne W. Holwerda, C. Howlett, H. Ibarra, M. J. Jarvis, D. H. Jones, P. R. Kafle, C. G. Lacey, R. Lange, M. Lara-Lopez, Angel R. Lopez-Sanchez, S. J. Maddox, B. F. Madore, T. Mcnaught-Roberts, A. J. Moffett, R. C. Nichol, M. S. Owers, D. Palamara, S. J. Penny, S. Phillipps, K. A. Pimbblet, C. C. Popescu, M. Prescott, R. Proctor, E. M. Sadler, A. E. Sansom, M. Seibert, R. Sharp, W. Sutherland, J. A. Vazquez-Mata, E. Van Kampen, S. M. Wilkins, R. Williams, A. H. Wright

Faculty and Staff Scholarship

The Galaxy And Mass Assembly (GAMA) survey is one of the largest contemporary spectroscopic surveys of low redshift galaxies. Covering an area of ∼286 deg2 (split among five survey regions) down to a limiting magnitude of r < 19.8 mag, we have collected spectra and reliable redshifts for 238 000 objects using the AAOmega spectrograph on the Anglo-Australian Telescope. In addition, we have assembled imaging data from a number of independent surveys in order to generate photometry spanning the wavelength range 1 nm–1 m. Here, we report on the recently completed spectroscopic survey and present a series of diagnostics to assess its final state and the quality of the redshift data. We also describe a number of survey aspects and procedures, or updates thereof, including changes to the input catalogue, redshifting and re-redshifting, and the derivation of ultraviolet, optical and near-infrared photometry. Finally, we present the second public release of GAMA data. In this release, we provide input catalogue and targeting information, spectra, redshifts, ultraviolet, optical and near-infrared photometry, single-component Sérsic fits, stellar masses, Hα-derived star formation rates, environment information, and group properties for all galaxies with r < 19.0 mag in two of our survey regions, and for all galaxies with r < 19.4 mag in a third region (72 225 objects in total). The data base serving these data is available at http://www.gama-survey.org/.

The Dependence Of The Av Prior For Sn Ia On Host Mass And Disc Inclination., Benne W. Holwerda, W. C. Keel, M. A. Kenworthy, K. J. Mack

Faculty and Staff Scholarship

Type Ia supernovae (SNe Ia) are used as ‘standard candles’ for cosmological distance scales. To fit their light-curve shape–absolute luminosity relation, one needs to assume an intrinsic colour and a likelihood of host galaxy extinction or a convolution of these, a colour distribution prior. The host galaxy extinction prior is typically assumed to be an exponential drop-off for the current supernova programmes ( P(AV)∝e−AV/τ0" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline-table; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: …

The Sizes Of Candidate Z~9-10 Galaxies : Confirmation Of The Bright Candels Sample And Relation With Luminosity And Mass., Benne W. Holwerda, R. J. Bouwens, P. A. Oesch, R. Smit, G. D. Illingworth, I. Labbe

Faculty and Staff Scholarship

Recently, a small sample of six z ∼ 9–10 candidates was discovered in CANDELS that are ~-´ 10 20 more luminous than any of the previous z ∼ 9–10 galaxies identified over the HUDF/XDF and CLASH fields. We measure the sizes of these candidates to map out the size evolution of galaxies from the earliest observable times. Their sizes are also used to provide a valuable constraint on whether these unusual galaxy candidates are at high redshift. Using galfit to derive sizes from the CANDELS F160W images of these candidates, we find a mean size of 0. 13 0. 0 …

The Spitzer Survey Of Stellar Structure In Galaxies (S4g) : Precise Stellar Mass Distributions From Automated Dust Correction At 3.6 Μm., Miguel Querejeta, Sharon Meidt, Eva Schinnerer, Mauricio Cisternas, Juan Carlos Muñoz-Mateos, Kartik Sheth, Johan H. Knapen, Glenn Van De Ven, Mark A. Norris, Reynier Peletier, Eija Laurikainen, Heikki Salo, Benne W. Holwerda, E. Athanassoula, Albert Bosma, Brent Groves, Luis C. Ho, Dimitri A. Gadotti, Dennis Zaritsky, Michael Regan, Joannah Hinz, Armando Gil De Paz, Karin Menendez-Delmestre, Mark Seibert, Trisha Mizusawa, Taehyun Kim, Santiago Erroz-Ferrer, Jarkko Laine, Sebastien Comeron

Faculty and Staff Scholarship

The mid-infrared is an optimal window to trace stellar mass in nearby galaxies and the 3.6 mm IRAC band has been exploited to this effect, but such mass estimates can be biased by dust emission. We present our pipeline to reveal the old stellar flux at 3.6 μm and obtain stellar mass maps for more than 1600 galaxies available from the Spitzer Survey of Stellar Structure in Galaxies (S4 G). This survey consists of images in two infrared bands (3.6 and 4.5 mm ), and we use the Independent Component Analysis (ICA) method presented in Meidt et al. to separate …

Origin Of The Diffuse, Far Ultraviolet Emission In The Interarm Regions Of M101., Alison F. Crocker, Rupali Chandar, Daniela Calzetti, Benne W. Holwerda, Claus Leitherer, Cristina C. Popescu, R. J. Tuffs

Faculty and Staff Scholarship

We present images from the Solar Blind Channel on the Hubble Space Telescope that resolve hundreds of farultraviolet (FUV) emitting stars in two ∼1 kpc2 interarm regions of the grand-design spiral M101. The luminosity functions of these stars are compared with predicted distributions from simple star formation histories, and are best reproduced when the star formation rate has recently declined (past 10–50 Myr). This pattern is consistent with stars forming within spiral arms and then streaming into the interarm regions. We measure the diffuse FUV surface brightness after subtracting all of the detected stars, clusters, and background galaxies. A residual …

The Spitzer Survey Of Stellar Structure In Galaxies (S4g) : Stellar Masses, Sizes, And Radial Profiles For 2352 Nearby Galaxies., Juan Carlos Muñoz-Mateos, Kartik Sheth, Michael Regan, Taehyun Kim, Jarkko Laine, Santiago Erroz-Ferrer, Armando Gil De Paz, Sebastien Comeron, Joannah Hinz, Eija Laurikainen, Heikki Salo, E. Athanassoula, Albert Bosma, Alexandre Y. Bouquin, Eva Schinnerer, Luis C. Ho, Johan H. Knapen, Sharon Meidt, Miguel Querejeta, Trisha Mizusawa, Mark Seibert, Seppo Laine, Helene M. Courtois

Faculty and Staff Scholarship

The Spitzer Survey of Stellar Structure in Galaxies is a volume, magnitude, and size-limited survey of 2352 nearby galaxies with deep imaging at 3.6 and 4.5 μm. In this paper, we describe our surface photometry pipeline and showcase the associated data products that we have released to the community. We also identify the physical mechanisms leading to different levels of central stellar mass concentration for galaxies with the same total stellar mass. Finally, we derive the local stellar mass–size relation at 3.6 μm for galaxies of different morphologies. Our radial profiles reach stellar mass surface densities below ~1 pc M …

Galaxy And Mass Assembly (Gama) Blended Spectra Catalogue : Strong Galaxy–Galaxy Lens And Occulting Galaxy Pair Candidates., Benne W. Holwerda, I. K. Baldry, M. Alpaslan, A. E. Bauer, J. Bland-Hawthorn, S. Brough, M. J. I. Brown, M. E. Cluver, C. J. Conselice, S. P. Driver, A. M. Hopkins, D. H. Jones, Angel R. Lopez-Sanchez, J. Loveday, M. J. Meyer, A. Moffett

Faculty and Staff Scholarship

We present the catalogue of blended galaxy spectra from the Galaxy And Mass Assembly (GAMA) survey. These are cases where light from two galaxies are significantly detected in a single GAMA fibre. Galaxy pairs identified from their blended spectrum fall into two principal classes: they are either strong lenses, a passive galaxy lensing an emission-line galaxy; or occulting galaxies, serendipitous overlaps of two galaxies, of any type. Blended spectra can thus be used to reliably identify strong lenses for follow-up observations (high-resolution imaging) and occulting pairs, especially those that are a late-type partly obscuring an early-type galaxy which are of …

High-Precision Time-Series Photometry For The Discovery And Characterization Of Transiting Exoplanets., Karen Alicia Collins 1962-

Electronic Theses and Dissertations

The discovery of more than a thousand planets orbiting stars other than the Sun (i.e. exoplanets) over the past 20 years has shown that planetary systems are commonplace in the Milky Way galaxy. However, these discoveries are only a starting point in the quest to answer one of the most compelling questions posed by mankind for centuries – "are we alone in the universe?". This research aims to help build the foundation needed to search for that answer by optimizing data reduction techniques, determining and refining fundamental properties of known exoplanets, and searching for new exoplanets. Many exoplanets have been …

Uv Luminosity Functions At Redshifts Z~4 To Z~10 : 10,000 Galaxies From Hst Legacy Fields., R. J. Bouwens, G. D. Illingworth, P. A. Oesch, M. Trenti, I. Labbe, L. Bradley, C. M. Carollo, P. G. Van Dokkum, V. Gonzalez, Benne W. Holwerda, M. Franx, L. Spitler, R. Smit, D. Magee

Faculty and Staff Scholarship

The remarkable Hubble Space Telescope (HST) data sets from the CANDELS, HUDF09, HUDF12, ERS, and BoRG/HIPPIES programs have allowed us to map the evolution of the rest-frame UV luminosity function (LF) from z ~ 10 to z ~ 4. We develop new color criteria that more optimally utilize the full wavelength coverage from the optical, near-IR, and mid-IR observations over our search fields, while simultaneously minimizing the incompleteness and eliminating redshift gaps. We have identified 5859, 3001, 857, 481, 217, and 6 galaxy candidates at z ~ 4, z ~ 5, z ~ 6, z ~ 7, z ~ 8, …

A Classical Morphological Analysis Of Galaxies In The Spitzer Survey Of Stellar Structure In Galaxies (S4g)., Ronald J. Buta, Kartik Sheth, E. Athanassoula, Albert Bosma, Johan H. Knapen, Eija Laurikainen, Heikki Salo, Debra M. Elmegreen, Luis C. Ho, Dennis Zaritsky, Helene M. Courtois, Joannah Hinz, Juan Carlos Muñoz-Mateos, Taehyun Kim, Michael Regan, Dimitri A. Gadotti, Armando Gil De Paz, Jarkko Laine, Karin Menendez-Delmestre, Sebastien Comeron, Santiago Erroz-Ferrer, Mark Seibert, Trisha Mizusawa, Benne W. Holwerda, Barry Madore

Faculty and Staff Scholarship

The Spitzer Survey of Stellar Structure in Galaxies (S4 G) 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 S4 G 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 …

High-Precision Photometric Redshifts From Spitzer/Irac : Extreme [3.6] - [4.5] Colors Identify Galaxies In The Redshift Range Z ~ 6.6 - 6.9., Renske Smit, Rychard J. Bouwens, Marijn Franx, Pascal A. Oesch, Matthew L. N. Ashby, S. P. Millner, Ivo Labbe, Benne W. Holwerda, Giovanni G. Fazio, J. S. Huang

Faculty and Staff Scholarship

One of the most challenging aspects of studying galaxies in the z  7 universe is the infrequent confirmation of their redshifts through spectroscopy, a phenomenon thought to occur from the increasing opacity of the intergalactic medium to Lyα photons at z > 6.5. The resulting redshift uncertainties inhibit the efficient search for [C II] in z ~ 7 galaxies with sub-millimeter instruments such as ALMA, given their limited scan speed for faint lines. One means by which to improve the precision of the inferred redshifts is to exploit the potential impact of strong nebular emission lines on the colors of …

Morphology Parameters : Substructure Identification In X-Ray Galaxy Clusters., Viral Parekh, Kurt Van Der Heyden, Chiara Ferrari, Garry Angus, Benne W. Holwerda

Faculty and Staff Scholarship

Context. In recent years multi-wavelength observations have shown the presence of substructures related to merging events in a large proportion of galaxy clusters. Clusters can be roughly grouped into two categories – relaxed and non-relaxed – and a proper characterisation of the dynamical state of these systems is crucial for both astrophysical and cosmological studies.

Aims. In this paper we investigate the use of a number of morphological parameters (Gini, M20, concentration, asymmetry, smoothness, ellipticity, and Gini of the second-order moment, GM) introduced to automatically classify clusters as relaxed or dynamically disturbed systems.

Methods. We apply our …

Globular Cluster Populations : First Results From S4g Early-Type Galaxies., Dennis Zaritsky, Manuel Aravena, E. Athanassoula, Albert Bosma, Sebastien Comeron, Bruce G. Elmegreen, Santiago Erroz-Ferrer, Dimitri A. Gadotti, Joannah Hinz, Luis C. Ho, Benne W. Holwerda, Johan H. Knapen, Jarkko Laine, Eija Laurikainen, Juan Carlos Munoz-Mateos, Heikki Salo, Kartik Sheth

Faculty and Staff Scholarship

Using 3.6μm images of 97 early-type galaxies, we develop and verify methodology to measure globular cluster populations from the S4G survey images. We find that (1) the ratio, TN, of the number of clusters, NCL, to parent galaxy stellar mass, M∗, rises weakly with M∗ for early-type galaxies with M∗ > 1010 M when we calculate galaxy masses using a universal stellar initial mass function (IMF) but that the dependence of TN on M∗ is removed entirely once we correct for the recently uncovered systematic variation of IMF with M∗; and (2) for M∗ < 1010 M, there is no trend between NCL and M∗, the scatter in TN is significantly larger (approaching two orders of magnitude), and there is evidence to support a previous, independent suggestion of two families of galaxies. The behavior of NCL in the lower-mass systems is more difficult to measure because these systems are inherently cluster-poor, but our results may add to previous evidence that large variations in cluster formation and destruction efficiencies are to be found among low-mass galaxies. The average fraction of stellar mass in clusters is ∼0.0014 for M∗ > 1010 M and can be as large …

Sn Ia Host Galaxy Properties And The Dust Extinction Distribution., Benne W. Holwerda, A. Reynolds, M. Smith, R. C. Kraan-Korteweg

Faculty and Staff Scholarship

Type Ia supernovae (SNeIa) display a complex relation with their host galaxies. An important prior to the fit of the supernovae's light curve is the distribution of host galaxy extinction values that can be encountered. The Sloan Digital Sky Survey SuperNova survey project has published light-curve fits using both mlcs2k2 and salt2. We use the former fits extinction parameter (AV) to map this distribution of extinction values. We explore the dependence of this distribution on four observables; the inclination of the host galaxy disc, radial position of the supernova, redshift of the supernova and host, and the level …

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, Kartik Sheth, Dimitri A. Gadotti, Myung Gyoon Lee, Dennis Zaritsky, Bruce G. Elmegreen, E. Athanassoula, Albert Bosma, Benne W. Holwerda, Luis C. Ho, Sebastien Comeron, Johan H. Knapen, Joannah Hinz, Juan Carlos Munoz-Mateos, Santiago Erroz-Ferrer, Ronald J. Buta, Minjin Kim, Eija Laurikainen, Heikki Salo, Barry F. Madore, Jarkko Laine, Karin Menendez-Delmestre, Michael Regan, Bonita De Swardt, Armando Gil De Paz, Mark Seibert, Trisha Mizusawa

Faculty and Staff Scholarship

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 …

Spitzer/Infrared Array Camera Near-Infrared Features In The Outer Parts Of S4g Galaxies., Seppo Laine, Johan H. Knapen, Juan Carlos Munoz-Mateos, Taehyun Kim, Sebastien Comeron, Marie Martig, Benne W. Holwerda, E. Athanassoula, Albert Bosma, Peter H. Johansson, Santiago Erroz-Ferrer, Dimitri A. Gadotti, Armando Gil De Paz, Joannah Hinz, Jarkko Laine, Eija Laurikainen, Karin Menendez-Delmestre, Trisha Mizusawa, Michael Regan, Heikki Salo, Kartik Sheth, Mark Seibert, Ronald J. Buta, Mauricio Cisternas, Bruce G. Elmegreen, Debra M. Elmegreen, Luis C. Ho, Barry F. Madore, Dennis Zaritsky

Faculty and Staff Scholarship

We present a catalogue and images of visually detected features, such as asymmetries, extensions, warps, shells, tidal tails, polar rings, and obvious signs of mergers or interactions, in the faint outer regions (at and outside of R25) of nearby galaxies. This catalogue can be used in future quantitative studies that examine galaxy evolution due to internal and external factors. We are able to reliably detect outer region features down to a brightness level of 0.03 MJy sr−1 pixel−1 at 3.6 μm in the Spitzer Survey of Stellar Structure in Galaxies (S4G). We also tabulate companion galaxies. We find asymmetries …