Author
Brent Groves
Other affiliations: Space Telescope Science Institute, Max Planck Society, Leiden University ...read more
Bio: Brent Groves is an academic researcher from University of Western Australia. The author has contributed to research in topics: Galaxy & Star formation. The author has an hindex of 63, co-authored 293 publications receiving 16591 citations. Previous affiliations of Brent Groves include Space Telescope Science Institute & Max Planck Society.
Topics: Galaxy, Star formation, Physics, Stellar mass, Astrophysics
Papers published on a yearly basis
Papers
More filters
••
TL;DR: In this paper, the authors present an analysis of the host properties of 85224 emission-line galaxies selected from the Sloan Digital Sky Survey and derive a new empirical classification scheme which cleanly separates star-forming galaxies, composite AGN-H ii galaxies, Seyferts and LINERs and study the host galaxy properties of these different classes of objects.
Abstract: We present an analysis of the host properties of 85224 emission-line galaxies selected from the Sloan Digital Sky Survey. We show that Seyferts and LINERs form clearly separated branches on the standard optical diagnostic diagrams. We derive a new empirical classification scheme which cleanly separates star-forming galaxies, composite AGN-H ii galaxies, Seyferts and LINERs and we study the host galaxy properties of these different classes of objects. LINERs are older, more massive, less dusty and more concentrated, and they and have higher velocity dispersions and lower [OIII] luminosities than Seyfert galaxies. Seyferts and LINERs are most strongly distinguished by their [OIII] luminosities. We then consider the quantity L[OIII]/σ 4 , which is an indicator of the black hole accretion rate relative to the Eddington rate. Remarkably, we find that at fixed L[OIII]/σ 4 , all differences between Seyfert and LINER host properties disappear. LINERs and Seyferts form a continuous sequence, with LINERs dominant at low L/LEDD and Seyferts dominant at high L/LEDD . These results suggest that the majority of LINERs are AGN and that the Seyfert/LINER dichotomy is analogous to the high/low-state transition for X-ray binary systems. We apply theoretical photo-ionization models and show that pure LINERs require a harder ionizing radiation field with lower ionization parameter than Seyfert galaxies, consistent with the low and high X-ray binary states.
2,116 citations
••
TL;DR: In this article, the authors presented a new library of fully-radiative shock models calculated with the MAPPINGS iii code, which consists of grids of models with shock velocities in the range vs=100-1000 km s −1 and magnetic parameters B/p n of 10 −4 -10 µG cm 3/2 for five different atomic abundance sets, and for a pre-shock density of 1.0 cm −3.
Abstract: We present a new library of fully-radiative shock models calculated with the MAPPINGS iii shock and photoionization code. The library consists of grids of models with shock velocities in the range vs=100-1000 km s −1 and magnetic parameters B/ p n of 10 −4 -10 µG cm 3/2 for five different atomic abundance sets, and for a pre-shock density of 1.0 cm −3 . Additionally, Solar abundance model grids have been calculated for densities of 0.01, 0.1, 10, 100, and 1000 cm −3 with the same range in vs and B/ p n. Each model includes components of both the radiative shock and its photoionized precursor, ionized by the EUV and soft X-ray radiation generated in the radiative gas. We present the details of the ionization structure, the column densities, and the luminosities of the shock and its precursor. Emission line ratio predictions are separately given for the shock and its precursor as well as for the composite shock+precursor structure to facilitate comparison with observations in cases where the shock and its precursor are not resolved. Emission line ratio grids for shock and shock+precursor are presented on standard line ratio diagnostic diagrams, and we compare these grids to observations of radio galaxies and a sample of AGN and star forming galaxies from the Sloan Digital Sky Survey. This library is available online, along with a suite of tools to enable the analysis of the shocks and the easy creation of emission line ratio diagnostic diagrams. These models represent a significant increase in parameter space coverage over previously available models, and therefore provide a unique tool in the diagnosis of emission by shocks. Subject headings: hydrodynamics - shock waves - ISM: abundances,- Galaxies: Nuclei, Galaxies: Seyfert - infrared: ISM, Ultraviolet: ISM, X-rays: ISM
768 citations
••
Max Planck Society1, National Radio Astronomy Observatory2, University of Maryland, College Park3, Ohio State University4, University of Toledo5, Princeton University6, McMaster University7, University of Massachusetts Amherst8, University of Cambridge9, University of Paris-Sud10, Stony Brook University11, Heidelberg University12, University of Hertfordshire13, ASTRON14, University of Wyoming15, University of Arizona16, Raytheon17, INAF18, Institut d'Astrophysique de Paris19, University of California, San Diego20, California Institute of Technology21, Leiden University22, Space Telescope Science Institute23, Louisiana State University24, DSM25, University of Cologne26
TL;DR: In this paper, the authors presented a large-scale spatial resolution map of the CO-to-H$2}$ conversion factor and dust-togas ratio (DGR) in 26 nearby, star-forming galaxies.
Abstract: We present ~{}kiloparsec spatial resolution maps of the CO-to-H$_{2}$ conversion factor ({$α$}$_{CO}$) and dust-to-gas ratio (DGR) in 26 nearby, star-forming galaxies. We have simultaneously solved for {$α$}$_{CO}$ and the DGR by assuming that the DGR is approximately constant on kiloparsec scales. With this assumption, we can combine maps of dust mass surface density, CO-integrated intensity, and H I column density to solve for both {$α$}$_{CO}$ and the DGR with no assumptions about their value or dependence on metallicity or other parameters. Such a study has just become possible with the availability of high-resolution far-IR maps from the Herschel key program KINGFISH, $^{12}$CO J = (2-1) maps from the IRAM 30 m large program HERACLES, and H I 21 cm line maps from THINGS. We use a fixed ratio between the (2-1) and (1-0) lines to present our {$α$}$_{CO}$ results on the more typically used $^{12}$CO J = (1-0) scale and show using literature measurements that variations in the line ratio do not affect our results. In total, we derive 782 individual solutions for {$α$}$_{CO}$ and the DGR. On average, {$α$}$_{CO}$ = 3.1 M $_{☉}$ pc$^{–2}$ (K km s$^{–1}$)$^{–1}$ for our sample with a standard deviation of 0.3 dex. Within galaxies, we observe a generally flat profile of {$α$}$_{CO}$ as a function of galactocentric radius. However, most galaxies exhibit a lower {$α$}$_{CO}$ value in the central kiloparsec{mdash}a factor of ~{}2 below the galaxy mean, on average. In some cases, the central {$α$}$_{CO}$ value can be factors of 5-10 below the standard Milky Way (MW) value of {$α$}$_{CO, MW}$ = 4.4 M $_{☉}$ pc$^{–2}$ (K km s$^{–1}$)$^{–1}$. While for {$α$}$_{CO}$ we find only weak correlations with metallicity, the DGR is well-correlated with metallicity, with an approximately linear slope. Finally, we present several recommendations for choosing an appropriate {$α$}$_{CO}$ for studies of nearby galaxies.
533 citations
••
TL;DR: In this article, the authors use the optical diagnostic Baldwin-Phillips-Terlevich (BPT) diagram as a tool for investigating the spectral properties of ensembles of active galaxies.
Abstract: We use the chemical evolution predictions of cosmological hydrodynamic simulations with our latest theoretical stellar population synthesis, photoionization, and shock models to predict the strong line evolution of ensembles of galaxies from z = 3 to the present day. In this paper, we focus on the brightest optical emission-line ratios, [N II]/Hα and [O III]/Hβ. We use the optical diagnostic Baldwin-Phillips-Terlevich (BPT) diagram as a tool for investigating the spectral properties of ensembles of active galaxies. We use four redshift windows chosen to exploit new near-infrared multi-object spectrographs. We predict how the BPT diagram will appear in these four redshift windows given different sets of assumptions. We show that the position of star-forming galaxies on the BPT diagram traces the interstellar medium conditions and radiation field in galaxies at a given redshift. Galaxies containing active galactic nucleus (AGN) form a mixing sequence with purely star-forming galaxies. This mixing sequence may change dramatically with cosmic time, due to the metallicity sensitivity of the optical emission-lines. Furthermore, the position of the mixing sequence may probe metallicity gradients in galaxies as a function of redshift, depending on the size of the AGN narrow-line region. We apply our latest slow shock models for gas shocked by galactic-scale winds. We show that at high redshift, galactic wind shocks are clearly separated from AGN in line ratio space. Instead, shocks from galactic winds mimic high metallicity starburst galaxies. We discuss our models in the context of future large near-infrared spectroscopic surveys.
464 citations
••
TL;DR: The Kingfish project (Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel) as discussed by the authors is an imaging and spectroscopic survey of 61 nearby galaxies, chosen to cover a wide range of galaxy properties and local interstellar medium (ISM) environments found in the nearby universe.
Abstract: The KINGFISH project (Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel) is an imaging and spectroscopic survey of 61 nearby (d < 30 Mpc) galaxies, chosen to cover a wide range of galaxy properties and local interstellar medium (ISM) environments found in the nearby universe. Its broad goals are to characterize the ISM of present-day galaxies, the heating and cooling of their gaseous and dust components, and to better understand the physical processes linking star formation and the ISM. KINGFISH is a direct descendant of the Spitzer Infrared Nearby Galaxies Survey (SINGS), which produced complete Spitzer imaging and spectroscopic mapping and a comprehensive set of multiwavelength ancillary observations for the sample. The Herschel imaging consists of complete maps for the galaxies at 70, 100, 160, 250, 350, and 500 μm. The spectral line imaging of the principal atomic ISM cooling lines ([O I] 63 μm, [O III] 88 μm, [N II] 122,205 μm, and [C II] 158 μm) covers the subregions in the centers and disks that already have been mapped in the mid-infrared with Spitzer. The KINGFISH and SINGS multiwavelength data sets combined provide panchromatic mapping of the galaxies sufficient to resolve individual star-forming regions, and tracing the important heating and cooling channels of the ISM, across a wide range of local extragalactic ISM environments. This article summarizes the scientific strategy for KINGFISH, the properties of the galaxy sample, the observing strategy, and data processing and products. It also presents a combined Spitzer and Herschel image atlas for the KINGFISH galaxies, covering the wavelength range 3.6–500 μm. All imaging and spectroscopy data products will be released to the Herschel user-generated product archives.
463 citations
Cited by
More filters
[...]
01 Aug 2001
TL;DR: The study of distributed systems which bring to life the vision of ubiquitous computing systems, also known as ambient intelligence, is concentrated on in this work.
Abstract: With digital equipment becoming increasingly networked, either on wired or wireless networks, for personal and professional use alike, distributed software systems have become a crucial element in information and communications technologies. The study of these systems forms the core of the ARLES' work, which is specifically concerned with defining new system software architectures, based on the use of emerging networking technologies. In this context, we concentrate on the study of distributed systems which bring to life the vision of ubiquitous computing systems, also known as ambient intelligence.
2,774 citations
••
TL;DR: In this paper, the authors review progress over the past decade in observations of large-scale star formation, with a focus on the interface between extragalactic and Galactic studies.
Abstract: We review progress over the past decade in observations of large-scale star formation, with a focus on the interface between extragalactic and Galactic studies. Methods of measuring gas contents and star-formation rates are discussed, and updated prescriptions for calculating star-formation rates are provided. We review relations between star formation and gas on scales ranging from entire galaxies to individual molecular clouds.
2,525 citations
••
TL;DR: In this paper, the authors present an analysis of the host properties of 85224 emission-line galaxies selected from the Sloan Digital Sky Survey and derive a new empirical classification scheme which cleanly separates star-forming galaxies, composite AGN-H ii galaxies, Seyferts and LINERs and study the host galaxy properties of these different classes of objects.
Abstract: We present an analysis of the host properties of 85224 emission-line galaxies selected from the Sloan Digital Sky Survey. We show that Seyferts and LINERs form clearly separated branches on the standard optical diagnostic diagrams. We derive a new empirical classification scheme which cleanly separates star-forming galaxies, composite AGN-H ii galaxies, Seyferts and LINERs and we study the host galaxy properties of these different classes of objects. LINERs are older, more massive, less dusty and more concentrated, and they and have higher velocity dispersions and lower [OIII] luminosities than Seyfert galaxies. Seyferts and LINERs are most strongly distinguished by their [OIII] luminosities. We then consider the quantity L[OIII]/σ 4 , which is an indicator of the black hole accretion rate relative to the Eddington rate. Remarkably, we find that at fixed L[OIII]/σ 4 , all differences between Seyfert and LINER host properties disappear. LINERs and Seyferts form a continuous sequence, with LINERs dominant at low L/LEDD and Seyferts dominant at high L/LEDD . These results suggest that the majority of LINERs are AGN and that the Seyfert/LINER dichotomy is analogous to the high/low-state transition for X-ray binary systems. We apply theoretical photo-ionization models and show that pure LINERs require a harder ionizing radiation field with lower ionization parameter than Seyfert galaxies, consistent with the low and high X-ray binary states.
2,116 citations
01 Jan 2005
TL;DR: The Monthly Notices as mentioned in this paper is one of the three largest general primary astronomical research publications in the world, published by the Royal Astronomical Society (RAE), and it is the most widely cited journal in astronomy.
Abstract: Monthly Notices is one of the three largest general primary astronomical research publications. It is an international journal, published by the Royal Astronomical Society. This article 1 describes its publication policy and practice.
2,091 citations
••
Space Telescope Science Institute1, University of California, Santa Cruz2, Johns Hopkins University3, Rutgers University4, Durham University5, University of Nottingham6, Harvard University7, University of Innsbruck8, University of Michigan9, DSM10, University of Edinburgh11, University of Massachusetts Amherst12, California Institute of Technology13, UK Astronomy Technology Centre14, University of California, Irvine15, Swinburne University of Technology16, University of Arizona17, Goddard Space Flight Center18, The Catholic University of America19, Hebrew University of Jerusalem20, University of Victoria21, University of California, Berkeley22, Texas A&M University23, University of Notre Dame24, Carnegie Institution for Science25, Smithsonian Institution26, Yale University27, University of Missouri–Kansas City28, University of California, Riverside29, Max Planck Society30, University of Pittsburgh31, Inter-University Centre for Astronomy and Astrophysics32, University of Barcelona33, European Southern Observatory34, University of Minnesota35, National Research Council36, Western Kentucky University37, Stanford University38, Atacama Large Millimeter Submillimeter Array39, University of Missouri40
TL;DR: The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) as discussed by the authors was designed to document the first third of galactic evolution, from z approx. 8 - 1.5 to test their accuracy as standard candles for cosmology.
Abstract: The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, from z approx. 8 - 1.5. It will image > 250,000 distant galaxies using three separate cameras on the Hubble Space Tele8cope, from the mid-UV to near-IR, and will find and measure Type Ia supernovae beyond z > 1.5 to test their accuracy as standard candles for cosmology. Five premier multi-wavelength sky regions are selected, each with extensive ancillary data. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to a stellar mass of 10(exp 9) solar mass to z approx. 2, reaching the knee of the UV luminosity function of galaxies to z approx. 8. The survey covers approximately 800 square arc minutes and is divided into two parts. The CANDELS/Deep survey (5(sigma) point-source limit H =27.7mag) covers approx. 125 square arcminutes within GOODS-N and GOODS-S. The CANDELS/Wide survey includes GOODS and three additional fields (EGS, COSMOS, and UDS) and covers the full area to a 50(sigma) point-source limit of H ? or approx. = 27.0 mag. Together with the Hubble Ultradeep Fields, the strategy creates a three-tiered "wedding cake" approach that has proven efficient for extragalactic surveys. Data from the survey are non-proprietary and are useful for a wide variety of science investigations. In this paper, we describe the basic motivations for the survey, the CANDELS team science goals and the resulting observational requirements, the field selection and geometry, and the observing design.
2,088 citations