Digital Commons Network^™

Galactic Bulge Feedback And Its Impact On Galaxy Evolution, Shikui Tang

Open Access Dissertations

Galactic bulges of early-type spirals and elliptical galaxies comprise primarily old stars, which account for more than half of the total stellar mass in the local Universe. These stars collectively generate a long-lasting feedback via stellar mass loss and Type Ia supernovae. According to the empirical stellar mass loss and supernova rates, the stellar ejecta can be heated to more than 107 K, forming a very hot, diffuse, and ironrich interstellar medium. Conventionally a strong galactic wind is expected, especially in low- and intermediate-mass early-type galaxies which have a relatively shallow potential well. X-ray observations, however, have revealed that both …

Galaxy Evolution At High-Redshift: Millimeter-Wavelength Surveys With The Aztec Camera, Kimberly S Scott

Doctoral Dissertations 1896 - February 2014

Galaxies detected by their thermal dust emission at submillimeter (submm) and millimeter (mm) wavelengths comprise a population of massive, intensely star-forming systems in the early Universe. These "submm/mm-galaxies", or SMGs, likely represent an important phase in the assembly and/or evolution of massive galaxies and are thought to be the progenitors of massive elliptical galaxies. While their projected number density as a function of source brightness provides key constraints on models of galaxy evolution, SMG surveys carried out over the past twelve years with the first generation of submm/mm-wavelength cameras have not imaged a large enough area to sufficient depths to …

Star Formation And Mass Assembly In High Redshift Galaxies, P. Santini, A. Fontana, A. Grazian, S. Salimbeni, F. Fiore, F. Fontanot, K. Boutsia, M. Castellano, S. Cristiani, C. De Santis, S. Gallozzi, E. Giallongo, N. Menci, M. Nonino, D. Paris, L. Pentericci, E. Vanzella

Astronomy Department Faculty Publication Series

Aims. The goal of this work is to infer the star formation properties and the mass assembly process of high redshift (0.3 ≤ z < 2.5) galaxies from their IR emission using the 24 μm band of MIPS-Spitzer. Methods. We used an updated version of the GOODS-MUSIC catalog, which has multiwavelength coverage from 0.3 to 24 μm and either spectroscopic or accurate photometric redshifts.We describe how the catalog has been extended by the addition of mid-IR fluxes derived from theMIPS 24 μm image.We compared two different estimators of the star formation rate (SFR hereafter). One is the total infrared emission derived from 24 μm, estimated using both synthetic and empirical IR templates. The other one is a multiwavelength fit to the full galaxy SED, which automatically accounts for dust reddening and age–star formation activity degeneracies. For both estimates, we computed the SFR density and the specific SFR. Results. We show that the two SFR indicators are roughly consistent, once the uncertainties involved are taken into account. However, they show a systematic trend, IR-based estimates exceeding the fit-based ones as the star formation rate increases. With this new catalog, we show that: a) at z > 0.3, the star formation rate is correlated well with stellar mass, and this relationship seems to steepen with redshift if one relies on IR–based estimates of the SFR; b) the contribution to the global SFRD by massive galaxies increases with redshift up to ≃ 2.5, more rapidly than for galaxies of lower mass, but appears to flatten at higher z; c) despite this increase, the most important contributors to the SFRD at any z are galaxies …

A Frequency Selective Bolometer Camera For Measuring Millimeter Spectral Energy Distributions, Daniel William Logan

Open Access Dissertations

Bolometers are the most sensitive detectors for measuring millimeter and submillimeter wavelength astrophysical signals. Cameras comprised of arrays of bolometers have already made significant contributions to the field of astronomy. A challenge for bolometer cameras is obtaining observations at multiple wavelengths. Traditionally, observing in multiple bands requires a partial disassembly of the instrument to replace bandpass filters, a task which prevents immediate spectral interrogation of a source. More complex cameras have been constructed to observe in several bands using beam splitters and dichroic filters, but the added complexity leads to physically larger instruments with reduced efficiencies. The SPEctral Energy Distribution …

The Aztec Millimeter-Wave Camera: Design, Integration, Performance, And The Characterization Of The (Sub-)Millimeter Galaxy Population, Jason Edward Austermann

Open Access Dissertations

One of the primary drivers in the development of large format millimeter detector arrays is the study of sub-millimeter galaxies (SMGs) - a population of very luminous high-redshift dust-obscured starbursts that are widely believed to be the dominant contributor to the Far-Infrared Background (FIB). The characterization of such a population requires the ability to map large patches of the (sub-)millimeter sky to high sensitivity within a feasible amount of time. I present this dissertation on the design, integration, and characterization of the 144-pixel AzTEC millimeter-wave camera and its application to the study of the sub-millimeter galaxy population. In particular, I …

A Systematic Study Of The Stellar Populations And Ism In Galaxies Out To The Virgo Cluster: Near Field Cosmology Within A Representative Slice Of The Local Universe, Rolf A. Jansen, Paul Scowen, Matthew Beasley, John Gallagher, Robert O'Connell, Daniela Calzetti, Sally Oey, Rogier Windhorst, Robert Woodruff

Astronomy Department Faculty Publication Series

We present a compelling case for a systematic and comprehensive study of the resolved and unresolved stellar populations, ISM, and immediate environments of galaxies throughout the local volume, defined here as D < 20 Mpc. This volume is our cosmic backyard and the smallest volume that encompasses environments as different as the Virgo, Ursa Major, Fornax and (perhaps) Eridanus clusters of galaxies, a large number and variety of galaxy groups, and several cosmic void regions. In each galaxy, through a pan-chromatic (160--1100nm) set of broad-band and diagnostic narrow-band filters, ISM structures and individual luminous stars to >~1 mag below the TRGB should be resolved on scales of <5 pc (at D <~ 20 Mpc, lambda ~ 800nm, for mu_I >~ 24 mag/arcsec^2 and m_{I,TRGB} <~ 27.5 mag). Resolved and unresolved stellar populations would be analyzed through color-magnitude and color-color diagram fitting and population synthesis modeling of multi-band colors and would yield physical properties such as spatially resolved star formation histories. The ISM within and around each galaxy would be analyzed using key narrow-band filters that distinguish photospheric from shock heating and provide information on the metallicity of the gas. Such a study would finally allow unraveling the global and spatially resolved star formation histories of galaxies, their assembly, satellite systems, and the dependences thereof on local and global environment within a truly representative cosmic volume. The proposed study is not feasible with current instrumentation but argues for a wide-field (>~250 arcmin^2), high-resolution (<~0.020"--0.065" [300--1000nm]), ultraviolet--near-infrared imaging facility on a 4m-class space-based observatory.

The Role Of Stellar Feedback In Galaxy Evolution, Li Zhiyuan

Open Access Dissertations

Aiming at understanding the role of stellar feedback in galaxy evolution, I present a study of the hot interstellar medium in several representative galaxies, based primarily on X-ray observations as well as theoretical modelling. I find that, in the massive disk galaxies NGC2613 and M104, the observed amount of hot gas is much less than that predicted by current galaxy formation models. Such a discrepancy suggests a lack of appropriate treatments of stellar/AGN feedback in these models. I also find that stellar feedback, primarily in the form of mass loss from evolved stars and energy released from supernovae, and presumably …

The Role Of Stellar Feedback In Galaxy Evolution, Zhiyuan Li

Doctoral Dissertations 1896 - February 2014

Aiming at understanding the role of stellar feedback in galaxy evolution, I present a study of the hot interstellar medium in several representative galaxies, based primarily on X-ray observations as well as theoretical modelling.

I find that, in the massive disk galaxies NGC2613 and M104, the observed amount of hot gas is much less than that predicted by current galaxy formation models. Such a discrepancy suggests a lack of appropriate treatments of stellar/AGN feedback in these models.

I also find that stellar feedback, primarily in the form of mass loss from evolved stars and energy released from supernovae, and presumably …

Beyond The Best-Fit Parameter: New Insight On Galaxy Structure Decomposition From Galphat, Ilsang Yoon, M Weinberg, N Katz

Astronomy Department Faculty Publication Series

We introduce a novel image decomposition package, Galphat, that provides robust estimates of galaxy surface brightness profiles using Bayesian Markov Chain Monte Carlo. The Galphat-determined posterior distribution of parameters enables us to assign rigorous statistical confidence intervals to maximum a posteriori estimates and to test complex galaxy formation and evolution hypotheses. We describe the Galphat algorithm, assess its performance using test image data, and demonstrate that it has sufficient speed for production analysis of a large galaxy sample. Finally we briefly introduce our ongoing science program to study the distribution of galaxy structural properties in the local universe using Galphat.

Structural Properties Of Central Galaxies In Groups And Clusters, Yc Guo, Dh Mcintosh, Hj Mo, N Katz, Fc Van Den Bosch, M Weinberg, Sm Weinmann, A Pasquali, Xh Yang

Astronomy Department Faculty Publication Series

Using a statistically representative sample of 911 central galaxies (CENs) from the Sloan Digital Sky Survey (SDSS) Data Release 4 group catalogue, we study how the structure (shape and size) of the first rank (by stellar mass) group and cluster members depends on (1) galaxy stellar mass (Mstar), (2) the global environment defined by the dark matter halo mass (Mhalo) of the host group and (3) the local environment defined by their special halocentric position. We quantify the structure of SDSS galaxies with a galfit-based pipeline that fits two-dimensional Sérsic models to the r-band image data. Through tests with simulated …

The Evolution Of Star Clusters: The Resolved-Star Approach, A Pellerin, Mj Meyer, J Harris, D Calzetti

Astronomy Department Faculty Publication Series

We present the first results of a new technique to detect, locate, and characterize young dissolving star clusters. Using Hubble Space Telescope/Advanced Camera for Surveys archival images of the nearby galaxy IC2574, we performed stellar PSF photometry and selected the most massive stars as our first test sample. We used a group-finding algorithm on the selected massive stars to find cluster candidates. We then plot the color-magnitude diagrams for each group, and use stellar evolutionary models to estimate their age. So far, we found 79 groups with ages of up to about 100 Myr, displaying various sizes and densities.

Radial Distribution Of Stars, Gas And Dust In Sings Galaxies. I. Surface Photometry And Morphology, Jc Munoz-Mateos, Ag De Paz, J Zamorano, S Boissier, Da Dale, Pg Perez-Gonzalez, J Gallego, Bf Madore, G Bendo, A Boselli, V Buat, D Calzetti, J Moustakas, Rc Kennicutt

Astronomy Department Faculty Publication Series

We present ultraviolet through far-infrared (FIR) surface brightness profiles for the 75 galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS). The imagery used to measure the profiles includes Galaxy Evolution Explorer UV data, optical images from Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory, and Sloan Digital Sky Survey, near-IR data from Two Micron All Sky Survey, and mid- and FIR images from Spitzer. Along with the radial profiles, we also provide multi-wavelength asymptotic magnitudes and several nonparametric indicators of galaxy morphology: the concentration index (C42), the asymmetry (A), the Gini coefficient (G …

Dust-Corrected Star Formation Rates Of Galaxies. I. Combinations Of H Alpha And Infrared Tracers, Rc Kennicutt, Cn Hao, D Calzetti, J Moustakas, Da Dale, G Bendo, Cw Engelbracht, Bd Johnson, Jc Lee

Astronomy Department Faculty Publication Series

We combine Hα emission-line and infrared (IR) continuum measurements of two samples of nearby galaxies to derive dust attenuation-corrected star formation rates (SFRs). We use a simple energy balance based method that has been applied previously to H II regions in the Spitzer Infrared Nearby Galaxies Survey, and extend the methodology to integrated measurements of galaxies. We find that our composite Hα + IR based SFRs are in excellent agreement with attenuation-corrected SFRs derived from integrated spectrophotometry, over the full range of SFRs (0.01-80 M sun yr-1) and attenuations (0-2.5 mag) studied. We find that the combination of Hα and …

Large Area Survey For Z=7 Galaxies In Sdf And Goods-N: Implications For Galaxy Formation And Cosmic Reionization, M Ouchi, B Mobasher, K Shimasaku, Hc Ferguson, Sm Fall, Y Ono, N Kashikawa, T Morokuma, K Nakajima, S Okamura, M Dickinson, M Giavalisco, K Ohta

Astronomy Department Faculty Publication Series

We present results of our large area survey for z'-band dropout galaxies at z = 7 in a 1568 arcmin2 sky area covering the SDF and GOODS-N fields. Combining our ultra-deep Subaru/Suprime-Cam z'- and y-band (λeff = 1 μm) images with legacy data of Subaru and Hubble Space Telescope, we have identified 22 bright z-dropout galaxies down to y = 26, one of which has a spectroscopic redshift of z = 6.96 determined from Lyα emission. The z = 7 luminosity function yields the best-fit Schechter parameters of ϕ* = 0.69+2.62−0.55 × 10−3 Mpc−3, …

Hubble Space Telescope/Advanced Camera For Surveys Morphology Of Ly Alpha Emitters At Redshift 5.7 In The Cosmos Field, Y Taniguchi, Et. Al.

Astronomy Department Faculty Publication Series

We present detailed morphological properties of Lyα emitters (LAEs) at z ≈ 5.7 in the COSMOS field based on Hubble Space Telescope Advanced Camera for Surveys (ACS) data. The ACS imaging in the F814W filter covered 85 LAEs of the 119 LAEs identified in the full two square degree field, and 47 LAEs of them are detected in the ACS images. Nearly half of them are spatially extended with a size larger than 0.15 arcsec (∼0.88 kpc at z = 5.7) and up to 0.4 arcsec (∼2.5 kpc at z = 5.7). The others are nearly unresolved compact objects. Two …

Expanding The Search For Galaxies At Z Similar To 7-10 With New Nicmos Parallel Fields, Alaina L. Henry, Brian Siana, Matthew A. Malkan, Matthew L.N. Ashby, Carrie R. Bridge, Ranga-Ram Chary, James W. Colbert, Mauro Giavalisco, Harry I. Teplitz, Patrick J. Mccarthy

Astronomy Department Faculty Publication Series

We have carried out a search for galaxies at z ∼ 7–10 in ∼14.4 arcmin2 of new NICMOS parallel imaging taken in the Great Observatories Origins Deep Survey (5.9 arcmin2), the Cosmic Origins Survey (7.2 arcmin2), and SSA22 (1.3 arcmin2). These images reach 5σ sensitivities of J110 = 26.0–27.5 (AB), and combined they increase the amount of deep near-infrared data by more than 60% in fields where the investment in deep optical data has already been made. We find no z > 7 candidates in our survey area, consistent with the Bouwens et al. measurements at z ∼ 7 and …

Biases And Uncertainties In Physical Parameter Estimates Of Lyman Break Galaxies From Broadband Photometry, Sk Lee, R Idzi, Hc Ferguson, Rs Somerville, T Wiklind, M Giavalisco

Astronomy Department Faculty Publication Series

We investigate the biases and uncertainties in estimates of physical parameters of high-redshift Lyman break galaxies (LBGs), such as stellar mass, mean stellar population age, and star formation rate (SFR), obtained from broadband photometry. These biases arise from the simplifying assumptions often used in fitting the spectral energy distributions (SEDs). By combining ΛCDM hierarchical structure formation theory, semianalytic treatments of baryonic physics, and stellar population synthesis models, we construct model galaxy catalogs from which we select LBGs at redshifts z ∼ 3.4, 4.0, and 5.0. The broadband photometric SEDs of these model LBGs are then analyzed by fitting galaxy template …

Mapping The Dark Matter From Uv Light At High Redshift: An Empirical Approach To Understand Galaxy Statistics, Kyoung-Soo Lee, Mauro Giavalisco, Charlie Conroy, Risa H. Wechsler, Henry C. Ferguson, Rachel S. Somerville, Mark E. Dickinson, Claudia M. Urry

Astronomy Department Faculty Publication Series

We present a simple formalism to interpret the observations of two galaxy statistics, the UV luminosity function (LF) and two-point correlation functions for star-forming galaxies at z∼4, 5, and 6 in the context of Λ cold dark matter cosmology. Both statistics are the result of how star formation takes place in dark matter halos, and thus are used to constrain how UV light depends on halo properties, in particular halo mass. The two physical quantities we explore are the star formation duty cycle, and the range of UV luminosity that a halo of mass M can have (mean and …

Two Bright Submillimeter Galaxies In A Z=4.05 Protocluster In Goods-North, And Accurate Radio-Infrared Photometric Redshifts, E Daddi, H Dannerbauer, D Stern, M Dickinson, G Morrison, D Elbaz, M Giavalisco, C Mancini, A Pope, H Spinrad

Astronomy Department Faculty Publication Series

No abstract provided.

The Nature Of Red Dwarf Galaxies, Y Wang, Xh Yang, Hj Mo, Fc Van Den Bosch, N Katz, A Pasquali, Dh Mcintosh, Sm Weinmann

Astronomy Department Faculty Publication Series

Using dark matter halos traced by galaxy groups selected from the Sloan Digital Sky Survey Data Release 4, we find that about 1/4 of the faint galaxies (^0.1 M_r – 5log h> – 17.05, hereafter dwarfs) that are the central galaxies in their own halo are not blue and star forming, as expected in standard models of galaxy formation, but are red. In contrast, this fraction is about 1/2 for dwarf satellite galaxies. Many red dwarf galaxies are physically associated with more massive halos. In total, about ~45% of red dwarf galaxies reside in massive halos as satellites, …

Feedback From Galactic Stellar Bulges And Hot Gaseous Haloes Of Galaxies, Sk Tang, Qd Wang, Y Lu, Hj Mo

Astronomy Department Faculty Publication Series

We demonstrate that the feedback from stellar bulges can, in principle, play an essential role in shaping the halo gas of galaxies with substantial bulge components by conducting 1D hydrodynamical simulations. The feedback model we consider consists of two distinct phases: (i) an early starburst during the bulge formation and (ii) a subsequent long-lasting mass and energy injection from stellar winds of low-mass stars and Type Ia supernovae. An energetic outward blastwave is initiated by the starburst and maintained and enhanced by the long-lasting stellar feedback. For a Milky Way like galactic bulge, this blastwave heats up the circum-galactic medium …

An Aztec 1.1 Mm Survey Of The Goods-N Field - Ii. Multiwavelength Identifications And Redshift Distribution, El Chapin, A Pope, D Scott, I Aretxaga, Je Austermann, Rr Chary, K Coppin, M Halpern, Dh Hughes, Jd Lowenthal, Ge Morrison, Ta Perera, Ks Scott, Gw Wilson, Min Yun

Astronomy Department Faculty Publication Series

We present results from a multiwavelength study of 29 sources (false detection probabilities <5 per cent) from a survey of the Great Observatories Origins Deep Survey-North (GOODS-N) field at 1.1 mm using the Astronomical Thermal Emission Camera (AzTEC). Comparing with existing 850 μm Submillimetre Common-User Bolometer Array (SCUBA) studies in the field, we examine differences in the source populations selected at the two wavelengths. The AzTEC observations uniformly cover the entire survey field to a 1σ depth of ∼1 mJy. Searching deep 1.4 GHz Very Large Array (VLA) and Spitzer 3–24 μm catalogues, we identify robust counterparts for 21 1.1 mm sources, and tentative associations for the remaining objects. The redshift distribution of AzTEC sources is inferred from available spectroscopic and photometric redshifts. We find a median redshift of z= 2.7, somewhat higher than z= 2.0 for 850 μm selected sources in the same field, and our lowest redshift identification lies at a spectroscopic redshift z= 1.1460. We measure the 850 μm to 1.1 mm colour of our sources and do not find …

X-Raying The Intergalactic O Vi Absorbers, Y Yao, Tm Tripp, Qd Wang, Cw Danforth, Cr Canizares, Jm Shull, Hl Marshall, L Song

Astronomy Department Faculty Publication Series

The observed intergalactic O VI absorbers at z>0 have been regarded as a significant reservoir of the "missing baryons." However, to fully understand how these absorbers contribute to the baryon inventory, it is crucial to determine whether the systems are collisionally ionized or photoionized (or both). Using the identified intergalactic O VI absorbers as tracers, we search for the corresponding X-ray absorption lines, which are useful for finding the missing baryons and for revealing the nature of the O VI absorbers. Stacking the Chandra grating spectra along six AGN sight lines, we obtain three spectra with signal-to-noise ratios of …

The Aztec/Sma Interferometric Imaging Survey Of Submillimeter-Selected High-Redshift Galaxies, Jd Younger, Gg Fazio, Js Huang, Min Yun, Gw Wilson, Mln Ashby, Ma Gurwell, Ab Peck, Gr Petitpas, Dj Wilner, Dh Hughes, I Aretxaga, S Kim, Ks Scott, J Austermann, T Perera, Jd Lowenthal

Astronomy Department Faculty Publication Series

We present results from a continuing interferometric survey of high-redshift submillimeter galaxies (SMGs) with the Submillimeter Array, including high-resolution (beam size ~2 arcsec) imaging of eight additional AzTEC 1.1 mm selected sources in the COSMOS field, for which we obtain six reliable (peak signal-to-noise ratio (S/N) >5 or peak S/N >4 with multiwavelength counterparts within the beam) and two moderate significance (peak S/N >4) detections. When combined with previous detections, this yields an unbiased sample of millimeter-selected SMGs with complete interferometric follow up. With this sample in hand, we (1) empirically confirm the radio-submillimeter association, (2) examine the submillimeter morphology—including …

Spatial Correlation Between Submillimetre And Lyman-Alpha Galaxies In The Ssa 22 Protocluster, Y Tamura, K Kohno, K Nakanishi, B Hatsukade, D Iono, Gw Wilson, Min Yun, T Takata, Y Matsuda, T Tosaki, H Ezawa, Ta Perera, Ks Scott, Je Austermann, Dh Hughes, I Aretxaga, A Chung, T Oshima, N Yamaguchi, K Tanaka, R Kawabe

Astronomy Department Faculty Publication Series

Lyman- emitters are thought to be young, low-mass galaxies with ages of 10⁸ yr (refs 1, 2). An overdensity of them in one region of the sky (the SSA 22 field) traces out a filamentary structure in the early Universe at a redshift of z 3.1 (equivalent to 15 per cent of the age of the Universe) and is believed to mark a forming protocluster^{3, 4}. Galaxies that are bright at (sub)millimetre wavelengths are undergoing violent episodes of star formation^{5, 6, 7, 8}, and there is evidence that they are preferentially associated with …

(Co)-C-12(J=1-0) On-The-Fly Mapping Survey Of The Virgo Cluster Spirals. I. Data And Atlas, E.J. Chung, M.-H. Rhee, H. Kim, Min S. Yun, M. Heyer, J. S. Young

Astronomy Department Faculty Publication Series

We have performed an On-The-Fly (OTF) mapping survey of ¹²CO(J = 1-0) emission in 28 Virgo cluster spiral galaxies using the Five College Radio Astronomy Observatory (FCRAO) 14 m telescope. This survey aims to characterize the CO distribution, kinematics, and luminosity of a large sample of galaxies covering the full extents of stellar disks, rather than sampling only the inner disks or the major axis as was done by many previous single dish and interferometric CO surveys. CO emission is detected in 20 galaxies among the 28 Virgo spirals observed. An atlas consisting of global measures, radial measures, …

How Do Galaxies Accrete Gas And Form Stars?, M Putman, P Henning, A Bolatto, D Keres, D Pisano, J Rosenberg, F Bigiel, G Bryan, D Calzetti

Astronomy Department Faculty Publication Series

Great strides have been made in the last two decades in determining how galaxies evolve from their initial dark matter seeds to the complex structures we observe at z = 0. The role of mergers has been documented through both observations and simulations, numerous satellites that may represent these initial dark matter seeds have been discovered in the Local Group, high redshift galaxies have been revealed with monstrous star formation rates, and the gaseous cosmic web has been mapped through absorption line experiments. Despite these efforts, the dark matter simulations that include baryons are still unable to accurately reproduce galaxies. …

Global Hot Gas In And Around The Galaxy, Qd Wang

Astronomy Department Faculty Publication Series

The hot interstellar medium traces the stellar feedback and its role in regulating the eco-system of the Galaxy. I review recent progress in understanding the medium, based largely on X-ray absorption line spectroscopy, complemented by X-ray emission and far-UV O VI absorption measurements. These observations enable us for the first time to characterize the global spatial, thermal, chemical, and kinematic properties of the medium. The results are generally consistent with what have been inferred from X-ray imaging of nearby galaxies similar to the Galaxy. It is clear that diffuse soft X-ray emitting/absorbing gas with a characteristic temperature of ~10^{6 …}

Dynamic S0 Galaxies: A Case Study Of Ngc 5866, J-T Li, Qd Wang, Z Li, Y Chen

Astronomy Department Faculty Publication Series

S0 galaxies are often thought to be passively evolved from spirals after star formation is quenched. To explore what is actually occurring in such galaxies, we present a multi-wavelength case study of NGC 5866—a nearby edge-on S0 galaxy in a relatively isolated environment. This study shows strong evidence for dynamic activities in the interstellar medium, which are most likely driven by supernova explosions in the galactic disk and bulge. Understanding these activities can have strong implications for studying the evolution of such galaxies. We utilize Chandra, Hubble Space Telescope, and Spitzer data as well as ground-based observations to …

Confronting Feedback Simulations With Observations Of Hot Gas In Elliptical Galaxies, Qd Wang

Astronomy Department Faculty Publication Series

Elliptical galaxies comprise primarily old stars, which collectively generate a long-lasting feedback via stellar mass-loss and Type Ia SNe. This feedback can be traced by X-ray-emitting hot gas in and around such galaxies, in which little cool gas is typically present. However, the X-ray-inferred mass, energy, and metal abundance of the hot gas are often found to be far less than what are expected from the feedback, particularly in so-called low L_X/L_B ellipticals. This “missing” stellar feedback is presumably lost in galaxy-wide outflows, which can play an essential role in galaxy evolution (e.g., explaining the observed …