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102. Galaxy And Mass Assembly (GAMA): stellar mass functions by Hubble type

Author

Kelvin, Lee S., primary, Driver, Simon P., additional, Robotham, Aaron S. G., additional, Taylor, Edward N., additional, Graham, Alister W., additional, Alpaslan, Mehmet, additional, Baldry, Ivan, additional, Bamford, Steven P., additional, Bauer, Amanda E., additional, Bland-Hawthorn, Joss, additional, Brown, Michael J. I., additional, Colless, Matthew, additional, Conselice, Christopher J., additional, Holwerda, Benne W., additional, Hopkins, Andrew M., additional, Lara-López, Maritza A., additional, Liske, Jochen, additional, López-Sánchez, Ángel R., additional, Loveday, Jon, additional, Norberg, Peder, additional, Phillipps, Steven, additional, Popescu, Cristina C., additional, Prescott, Matthew, additional, Sansom, Anne E., additional, and Tuffs, Richard J., additional

Published
2014
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104. Galaxy And Mass Assembly (GAMA): the wavelength-dependent sizes and profiles of galaxies revealed by MegaMorph

Author

Vulcani, Benedetta, primary, Bamford, Steven P., additional, Häußler, Boris, additional, Vika, Marina, additional, Rojas, Alex, additional, Agius, Nicola K., additional, Baldry, Ivan, additional, Bauer, Amanda E., additional, Brown, Michael J. I., additional, Driver, Simon, additional, Graham, Alister W., additional, Kelvin, Lee S., additional, Liske, Jochen, additional, Loveday, Jon, additional, Popescu, Cristina C., additional, Robotham, Aaron S. G., additional, and Tuffs, Richard J., additional

Published
2014
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105. Galaxy And Mass Assembly (GAMA): ugrizYJHK Sérsic luminosity functions and the cosmic spectral energy distribution by Hubble type

Author

Kelvin, Lee S., primary, Driver, Simon P., additional, Robotham, Aaron S. G., additional, Graham, Alister W., additional, Phillipps, Steven, additional, Agius, Nicola K., additional, Alpaslan, Mehmet, additional, Baldry, Ivan, additional, Bamford, Steven P., additional, Bland-Hawthorn, Joss, additional, Brough, Sarah, additional, Brown, Michael J. I., additional, Colless, Matthew, additional, Conselice, Christopher J., additional, Hopkins, Andrew M., additional, Liske, Jochen, additional, Loveday, Jon, additional, Norberg, Peder, additional, Pimbblet, Kevin A., additional, Popescu, Cristina C., additional, Prescott, Matthew, additional, Taylor, Edward N., additional, and Tuffs, Richard J., additional

Published
2014
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106. The effects of dust on the photometric parameters of decomposed disks and bulges

Author

Pastrav, Bogdan Adrian, Popescu, Cristina, Tuffs, Richard J., Sansom, Anne E., Pastrav, Bogdan Adrian, Popescu, Cristina, Tuffs, Richard J., and Sansom, Anne E.

Abstract

We present results of a study to quantify the effects of dust on the derived photometric parameters of disk and bulges obtained from bulge-disk decomposition: scale-length, effective radius, Sérsic index, disk axis-ratio, and bulge-to-disk ratio. The dust induced changes in these parameters were obtained by fitting simulated images of composite systems (containing a disk and a bulge) produced using radiative transfer calculations. The simulations were fitted with the GALFIT 3.0.2 data analysis algorithm. Fits were done with both a combination of an exponential plus a variable-index Sérsic function as well as with a combination of two variable-index Sérsic functions. We find that dust is biasing the derived exponential scale-length of decomposed disks towards smaller values than would be otherwise derived if the galaxy were to have no bulge. Similarly, the derived bulge-to-disk ratio is biased towards smaller values. However, the derived axis-ratio of the disk is not changed in the decomposition process. The derived effective radius of decomposed disks of systems having exponential bulges is found to be less affected by dust when fits are done with two variable-index Sérsic functions. For the same type of fits dust is found to bias the value of the derived effective radius of decomposed disks towards lower values for systems having de Vaucouleurs bulges. © ESO, 2013.

Published
2013

107. Galaxy And Mass Assembly (GAMA): Spectroscopic analysis

Author

Hopkins, Andrew M., Driver, Simon, Brough, Sarah, Owers, Matt S, Bauer, Amanda E, Gunawardhana, Madusha, Cluver, M E, Colless, Matthew, Foster, C, Lara-Lopez, M A, Roseboom, I, Sharp, Robert, Baldry, I. K., Steele, O, Brown, M J I, Liske, Jochen, Norberg, P, Robotham, A. S. G., Bamford, Steven P., Bland-Hawthorn, Joss, Drinkwater, Michael John, van Kampen, E, Loveday, J, Meyer, M, Peacock, John A, Tuffs, Richard J, Agius, N, Alpaslan, M, Andrae, Ellen, Cameron, E, Cole, Shaun, Ching, J. H. Y., Christodoulou, L, Conselice, Christopher, Croom, S, Cross, N J G, De Propris, Roberto, Hopkins, Andrew M., Driver, Simon, Brough, Sarah, Owers, Matt S, Bauer, Amanda E, Gunawardhana, Madusha, Cluver, M E, Colless, Matthew, Foster, C, Lara-Lopez, M A, Roseboom, I, Sharp, Robert, Baldry, I. K., Steele, O, Brown, M J I, Liske, Jochen, Norberg, P, Robotham, A. S. G., Bamford, Steven P., Bland-Hawthorn, Joss, Drinkwater, Michael John, van Kampen, E, Loveday, J, Meyer, M, Peacock, John A, Tuffs, Richard J, Agius, N, Alpaslan, M, Andrae, Ellen, Cameron, E, Cole, Shaun, Ching, J. H. Y., Christodoulou, L, Conselice, Christopher, Croom, S, Cross, N J G, and De Propris, Roberto

Abstract

The Galaxy And Mass Assembly (GAMA) survey is a multiwavelength photometric and spectroscopic survey, using the AAOmega spectrograph on the Anglo-Australian Telescope to obtain spectra for up to ~300 000 galaxies over 280 deg2, to a limiting magnitude of

Published
2013

108. Galaxy and mass assembly (GAMA): The life and times of L* galaxies

Author

Robotham, A. S. G., Liske, Jochen, Driver, Simon P, Sansom, Anne E, Baldry, Ivan, Bauer, Amanda E, Bland-Hawthorn, Jonathan, Brough, Sarah, Brown, M J I, Colless, Matthew, Christodoulou, L, Drinkwater, Michael John, Tuffs, Richard J, Sharp, Robert, Hopkins, Andrew M., Robotham, A. S. G., Liske, Jochen, Driver, Simon P, Sansom, Anne E, Baldry, Ivan, Bauer, Amanda E, Bland-Hawthorn, Jonathan, Brough, Sarah, Brown, M J I, Colless, Matthew, Christodoulou, L, Drinkwater, Michael John, Tuffs, Richard J, Sharp, Robert, and Hopkins, Andrew M.

Abstract

In this work, we investigate in detail the effects the local environment (groups and pairs) has on galaxies with stellar mass similar to the MilkyWay (L* galaxies). A volume limited sample of 6150 galaxies are visually classified to determine the emission

Published
2013

109. Galaxy And Mass Assembly (GAMA): The 0.013 < z < 0.1 cosmic spectral energy distribution from 0.1 m to 1 mm

Author

Driver, Simon, Robotham, A. S. G., Kelvin, L S, Alpaslan, M, Baldry, I. K., Bamford, Steven P., Brough, Sarah, Brown, M, Hopkins, Andrew M., Liske, Jochen, Colless, Matthew, Madore, Barry, Sharp, Robert, Tuffs, Richard J, van Kampen, E, Andrae, Ellen, Driver, Simon, Robotham, A. S. G., Kelvin, L S, Alpaslan, M, Baldry, I. K., Bamford, Steven P., Brough, Sarah, Brown, M, Hopkins, Andrew M., Liske, Jochen, Colless, Matthew, Madore, Barry, Sharp, Robert, Tuffs, Richard J, van Kampen, E, and Andrae, Ellen

Abstract

We use the Galaxy And Mass Assembly survey (GAMA) I data set combined with GALEX, Sloan Digital Sky Survey (SDSS) and UKIRT Infrared Deep Sky Survey (UKIDSS) imaging to construct the low-redshift (z < 0.1) galaxy luminosity functions in FUV, NUV, ugriz

Published
2012

110. Galaxy and Mass Assembly (GAMA): the star formation rate dependence of the stellar initial mass function

Author

Gunawardhana, M, Hopkins, Andrew M., Sharp, Robert, Brough, S, Taylor, E, Bland-Hawthorn, J., Maraston, C, Tuffs, Richard J, Popescu, C. C., Wijesinghe, D. B., Jones, D Heath, Croom, S, Gunawardhana, M, Hopkins, Andrew M., Sharp, Robert, Brough, S, Taylor, E, Bland-Hawthorn, J., Maraston, C, Tuffs, Richard J, Popescu, C. C., Wijesinghe, D. B., Jones, D Heath, and Croom, S

Abstract

The stellar initial mass function (IMF) describes the distribution in stellar masses produced from a burst of star formation. For more than 50 yr, the implicit assumption underpinning most areas of research involving the IMF has been that it is universal, regardless of time and environment. We measure the high-mass IMF slope for a sample of low-to-moderate redshift galaxies from the Galaxy and Mass Assembly survey. The large range in luminosities and galaxy masses of the sample permits the exploration of underlying IMF dependencies. A strong IMF-star formation rate dependency is discovered, which shows that highly star-forming galaxies form proportionally more massive stars (they have IMFs with flatter power-law slopes) than galaxies with low star formation rates. This has a significant impact on a wide variety of galaxy evolution studies, all of which rely on assumptions about the slope of the IMF. Our result is supported by, and provides an explanation for, the results of numerous recent explorations suggesting a variation of or evolution in the IMF.

Published
2011

111. Galaxy and Mass Assembly: FUV, NUV, ugrizYJHK Petrosian, Kron and Sérsic photometry

Author

Hill, David T., Kelvin, Lee S., Driver, Simon P., Robotham, Aaron S. G., Cameron, Ewan, Cross, Nicholas, Andrae, Ellen, Baldry, Ivan K., Bamford, Steven P., Bland-Hawthorn, Joss, Brough, Sarah, Conselice, Christopher J., Dye, Simon, Hopkins, Andrew M., Liske, Jochen, Loveday, Jon, Norberg, Peder, Peacock, John A., Croom, Scott M., Frenk, Carlos S., Graham, Alister W., Jones, D. Heath, Kuijken, Konrad, Madore, Barry F., Nichol, Robert C., Parkinson, Hannah R., Phillipps, Steven, Pimbblet, Kevin A., Popescu, Cristina C., Prescott, Matthew, Seibert, Mark, Sharp, Rob G., Sutherland, Will J., Thomas, Daniel, Tuffs, Richard J., van Kampen, Elco, Hill, David T., Kelvin, Lee S., Driver, Simon P., Robotham, Aaron S. G., Cameron, Ewan, Cross, Nicholas, Andrae, Ellen, Baldry, Ivan K., Bamford, Steven P., Bland-Hawthorn, Joss, Brough, Sarah, Conselice, Christopher J., Dye, Simon, Hopkins, Andrew M., Liske, Jochen, Loveday, Jon, Norberg, Peder, Peacock, John A., Croom, Scott M., Frenk, Carlos S., Graham, Alister W., Jones, D. Heath, Kuijken, Konrad, Madore, Barry F., Nichol, Robert C., Parkinson, Hannah R., Phillipps, Steven, Pimbblet, Kevin A., Popescu, Cristina C., Prescott, Matthew, Seibert, Mark, Sharp, Rob G., Sutherland, Will J., Thomas, Daniel, Tuffs, Richard J., and van Kampen, Elco

Published
2010

113. Dust Emission and Star Formation in Stephan's Quintet

Author

Natale, Giovanni, Tuffs, Richard J, Xu, C K, Popescu, Cristina C, Fischera, Jörg, Lisenfeld, U, Lu, N, Appleton, P N, Dopita, Michael, Duc, P-A, Gao, Y, Reach, William, Sulentic, J W, Yun, M S, Natale, Giovanni, Tuffs, Richard J, Xu, C K, Popescu, Cristina C, Fischera, Jörg, Lisenfeld, U, Lu, N, Appleton, P N, Dopita, Michael, Duc, P-A, Gao, Y, Reach, William, Sulentic, J W, and Yun, M S

Abstract

We analyze a comprehensive set of MIR/FIR observations of Stephan's Quintet (SQ), taken with the Spitzer Space Telescope. Our study reveals the presence of a luminous (LIR ≈4.6×1043 erg s-1) and extended component of infrared dust emission, not connect

Published
2010

114. Galaxy and mass assembly (GAMA): Optimal tiling of dense surveys with a multi-object spectrograph

Author

Robotham, Aaron, Driver, Simon P, Norberg, P, Baldry, I. K., Bamford, Steven P., Hopkins, Andrew M., Liske, Jochen, Loveday, J, Peacock, John A, Cameron, E, van Kampen, E, Sharp, Robert, Tuffs, Richard J, Robotham, Aaron, Driver, Simon P, Norberg, P, Baldry, I. K., Bamford, Steven P., Hopkins, Andrew M., Liske, Jochen, Loveday, J, Peacock, John A, Cameron, E, van Kampen, E, Sharp, Robert, and Tuffs, Richard J

Abstract

A heuristic greedy algorithm is developed for efficiently tiling spatially dense redshift surveys. In its first application to the Galaxy and Mass Assembly (GAMA) redshift survey we find it rapidly improves the spatial uniformity of our data, and naturally corrects for any spatial bias introduced by the 2dF multi-object spectrograph. We make conservative predictions for the final state of the GAMA redshift survey after our final allocation of time, and can be confident that even if worse than typical weather affects our observations, all of our main survey requirements will be met.

Published
2010

115. Clouds, filaments, and protostars: The Herschel Hi-GAL Milky Way

Author

Molinari, Sergio, Swinyard, Bruce M., Bally, John, Barlow, Michael J., Bernard, Jean P., Martin, Peter G., Moore, Toby J.T., Noriega-Crespo, Alberto, Plume, René, Testi, Leonardo, Zavagno, Annie, Abergel, Alain, Ali, Babar, Anderson, Lynn D., Ándré, P., Baluteau, Jean P., Battersby, Cara, Beltrán, Maria T., Benedettini, Milena, Billot, Nicolas, Blommaert, Joris A.D.L., Bontemps, Sylvain, Boulanger, François, van den Brand, Jan F.J., Brunt, Christopher M., Burton, Michael G., Calzoletti, Luca, Carey, Sean J., Caselli, Paola E.S., Cesaroni, Riccardo, Cernicharo, José R., Chakrabarti, Sukanya, Chrysostomou, Antonio C., Cohen, Martin G., Compiegne, Mathieu, De Bernardis, Paolo, De Gasperis, Giancarlo, Di Giorgio, Anna Maria, Elia, D., Faustini, Fabiana, Flagey, N., Fukui, Yasuo, Fuller, Gary A., Ganga, Ken M., Garcia-Lario, Pedro, Glenn, Jason, Goldsmith, Paul F., Griffin, Matthew J., Hoare, Matthew J., Huang, Maohai, Ikhenaode, David, Joblin, Christine, Joncas, Gilles, Juvela, Mika, Kirk, Jason M., Lagache, Guilaine, Li, Jin Zeng, Lim, Tanya L., Lord, Steven D., Marengo, Massimo, Marshall, Douglas J., Masi, Silvia, Massi, Fabrizio, Matsuura, Makiko, Minier, Vincent, Miville-Deschênes, Marc Antoine, Montier, Ludovic A., Morgan, L.K., Motte, Frédérique, Mottram, Joseph C., Müller, Thomas G., Natoli, Paolo, Neves, J., Olmi, Luca, Paladini, Roberta, Paradis, Delphine, Parsons, Harriet A.L., Peretto, Nicolas, Pestalozzi, Michele R., Pezzuto, Stefano, Piacentini, Francesco, Piazzo, Lorenzo, Polychroni, Danae, Pomarès, M., Popescu, Cristina C., Reach, William T., Ristorcelli, Isabelle, Robitaille, J.F., Robitaille, Thomas P., Rodón, Javier A., Roy, Arabindo, Royer, Pierre, Russeil, Delphine, Saraceno, Paolo, Sauvage, Marc André, Schilke, Peter, Schisano, Eugenio, Schneider, Nicola, Schuller, Frédéric, Schulz, Bernhard, Sibthorpe, Bruce, Smith, Howard A., Smith, Michael D., Spinoglio, Luigi, Stamatellos, Dimitris, Strafella, Francesco, Stringfellow, Guy S., Sturm, Eckhard, Taylor, Russ S., Thompson, M.A., Traficante, Alessio, Tuffs, Richard J., Umana, Grazia M., Valenziano, Luca, Vavrek, Roland, Veneziani, Milena, Viti, Serena, Waelkens, C., Ward-Thompson, Derek, White, Glenn J., Wilcock, Lawrence A., Wyrowski, Friedrich, Yorke, Harold W., Zhang, Qizhou, Molinari, Sergio, Swinyard, Bruce M., Bally, John, Barlow, Michael J., Bernard, Jean P., Martin, Peter G., Moore, Toby J.T., Noriega-Crespo, Alberto, Plume, René, Testi, Leonardo, Zavagno, Annie, Abergel, Alain, Ali, Babar, Anderson, Lynn D., Ándré, P., Baluteau, Jean P., Battersby, Cara, Beltrán, Maria T., Benedettini, Milena, Billot, Nicolas, Blommaert, Joris A.D.L., Bontemps, Sylvain, Boulanger, François, van den Brand, Jan F.J., Brunt, Christopher M., Burton, Michael G., Calzoletti, Luca, Carey, Sean J., Caselli, Paola E.S., Cesaroni, Riccardo, Cernicharo, José R., Chakrabarti, Sukanya, Chrysostomou, Antonio C., Cohen, Martin G., Compiegne, Mathieu, De Bernardis, Paolo, De Gasperis, Giancarlo, Di Giorgio, Anna Maria, Elia, D., Faustini, Fabiana, Flagey, N., Fukui, Yasuo, Fuller, Gary A., Ganga, Ken M., Garcia-Lario, Pedro, Glenn, Jason, Goldsmith, Paul F., Griffin, Matthew J., Hoare, Matthew J., Huang, Maohai, Ikhenaode, David, Joblin, Christine, Joncas, Gilles, Juvela, Mika, Kirk, Jason M., Lagache, Guilaine, Li, Jin Zeng, Lim, Tanya L., Lord, Steven D., Marengo, Massimo, Marshall, Douglas J., Masi, Silvia, Massi, Fabrizio, Matsuura, Makiko, Minier, Vincent, Miville-Deschênes, Marc Antoine, Montier, Ludovic A., Morgan, L.K., Motte, Frédérique, Mottram, Joseph C., Müller, Thomas G., Natoli, Paolo, Neves, J., Olmi, Luca, Paladini, Roberta, Paradis, Delphine, Parsons, Harriet A.L., Peretto, Nicolas, Pestalozzi, Michele R., Pezzuto, Stefano, Piacentini, Francesco, Piazzo, Lorenzo, Polychroni, Danae, Pomarès, M., Popescu, Cristina C., Reach, William T., Ristorcelli, Isabelle, Robitaille, J.F., Robitaille, Thomas P., Rodón, Javier A., Roy, Arabindo, Royer, Pierre, Russeil, Delphine, Saraceno, Paolo, Sauvage, Marc André, Schilke, Peter, Schisano, Eugenio, Schneider, Nicola, Schuller, Frédéric, Schulz, Bernhard, Sibthorpe, Bruce, Smith, Howard A., Smith, Michael D., Spinoglio, Luigi, Stamatellos, Dimitris, Strafella, Francesco, Stringfellow, Guy S., Sturm, Eckhard, Taylor, Russ S., Thompson, M.A., Traficante, Alessio, Tuffs, Richard J., Umana, Grazia M., Valenziano, Luca, Vavrek, Roland, Veneziani, Milena, Viti, Serena, Waelkens, C., Ward-Thompson, Derek, White, Glenn J., Wilcock, Lawrence A., Wyrowski, Friedrich, Yorke, Harold W., and Zhang, Qizhou

Abstract

We present the first results from the science demonstration phase for the Hi-GAL survey, the Herschel key program that will map the inner Galactic plane of the Milky Way in 5 bands. We outline our data reduction strategy and present some science highlights on the two observed 2° × 2° tiles approximately centered at l = 30° and l = 59°. The two regions are extremely rich in intense and highly structured extended emission which shows a widespread organization in filaments. Source SEDs can be built for hundreds of objects in the two fields, and physical parameters can be extracted, for a good fraction of them where the distance could be estimated. The compact sources (which we will call cores' in the following) are found for the most part to be associated with the filaments, and the relationship to the local beam-averaged column density of the filament itself shows that a core seems to appear when a threshold around AV ? 1 is exceeded for the regions in the l = 59° field; a AV value between 5 and 10 is found for the l = 30° field, likely due to the relatively higher distances of the sources. This outlines an exciting scenario where diffuse clouds first collapse into filaments, which later fragment to cores where the column density has reached a critical level. In spite of core L/M ratios being well in excess of a few for many sources, we find core surface densities between 0.03 and 0.5 g cm -2. Our results are in good agreement with recent MHD numerical simulations of filaments forming from large-scale converging flows.

Published
2010

116. The Energy Output of the Universe from 0.1 to 1000 μm

Author

Driver, Simon P., Popescu, Cristina, Tuffs, Richard J., Graham, Alister W., Liske, Jochen, Baldry, Ivan, Driver, Simon P., Popescu, Cristina, Tuffs, Richard J., Graham, Alister W., Liske, Jochen, and Baldry, Ivan

Abstract

The dominant source of electromagnetic energy in the universe today (over ultraviolet, optical, and near-infrared wavelengths) is starlight. However, quantifying the amount of starlight produced has proved difficult due to interstellar dust grains that attenuate some unknown fraction of the light. Combining a recently calibrated galactic dust model with observations of 10,000 nearby galaxies, we find that (integrated over all galaxy types and orientations) only 11% ± 2% of the 0.1 μm photons escape their host galaxies; this value rises linearly (with log λ) to 87% ± 3% at 2.1 μm. We deduce that the energy output from stars in the nearby universe is (1.6 ± 0.2) × 1035 W Mpc−3, of which (0.9 ± 0.1) × 1035 W Mpc−3 escapes directly into the intergalactic medium. Some further ramifications of dust attenuation are discussed, and equations that correct individual galaxy flux measurements for its effect are provided.

Published
2008

117. Dust in galaxies

Author

Popescu, Cristina C., Tuffs, Richard J., Mioc, Vasile, Dumitrache, Cristiana, Popescu, Nedelia A., Popescu, Cristina C., Tuffs, Richard J., Mioc, Vasile, Dumitrache, Cristiana, and Popescu, Nedelia A.

Published
2008

120. MegaMorph – multiwavelength measurement of galaxy structure: complete Sérsic profile information from modern surveys

Author

Häußler, Boris, primary, Bamford, Steven P., additional, Vika, Marina, additional, Rojas, Alex L., additional, Barden, Marco, additional, Kelvin, Lee S., additional, Alpaslan, Mehmet, additional, Robotham, Aaron S. G., additional, Driver, Simon P., additional, Baldry, I. K., additional, Brough, Sarah, additional, Hopkins, Andrew M., additional, Liske, Jochen, additional, Nichol, Robert C., additional, Popescu, Cristina C., additional, and Tuffs, Richard J., additional

Published
2013
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121. Powerful High-Velocity Dispersion Molecular Hydrogen Associated with an Intergalactic Shock Wave in Stephan's Quintet

Author

Appleton, P N, Xu, Kevin C, Reach, William, Dopita, Michael, Gao, Y, Lu, N, Popescu, Cristina C, Sulentic, J W, Tuffs, Richard J, Yun, M S, Appleton, P N, Xu, Kevin C, Reach, William, Dopita, Michael, Gao, Y, Lu, N, Popescu, Cristina C, Sulentic, J W, Tuffs, Richard J, and Yun, M S

Abstract

We present the discovery of strong mid-infrared emission lines of molecular hydrogen of apparently high-velocity dispersion (∼870 km s -1) originating from a group-wide shock wave in Stephan's Quintet. These Spitzer Space Telescope observations reveal e

Published
2006

122. Modeling the Pan-Spectral Energy Distribution of Starburst Galaxies. III. Emission Line Diagnostics of Ensembles of Evolving H II Regions

Author

Dopita, Michael, Fischera, Joerg, Sutherland, Ralph, Kewley, Lisa, Leitherer, Claus, Tuffs, Richard J, Popescu, Cristina C, van Breugel, Wil, Groves, Brent, Dopita, Michael, Fischera, Joerg, Sutherland, Ralph, Kewley, Lisa, Leitherer, Claus, Tuffs, Richard J, Popescu, Cristina C, van Breugel, Wil, and Groves, Brent

Abstract

We build, as far as theory will permit, self-consistent model H II regions around central clusters of aging stars. These produce strong emission line diagnostics applicable to either individual H II regions in galaxies or to the integrated emission line spectra of disk or starburst galaxies. The models assume that the expansion and internal pressure of individual H II regions is driven by the net input of mechanical energy from the central cluster, be it through winds or supernova events. This eliminates the ionization parameter as a free variable, replacing it with a parameter that depends on the ratio of the cluster mass to the pressure in the surrounding interstellar medium. These models explain why H II regions with low abundances have high excitation and demonstrate that at least part of the warm ionized medium is the result of overlapping faint, old, large, and low-pressure H II regions. We present line ratios (at both optical and IR wavelengths) that provide reliable abundance diagnostics for both single H II regions or for integrated galaxy spectra, and we find a number that can be used to estimate the mean age of the cluster stars exciting individual H II regions.

Published
2006

123. Modeling the Pan-Spectral Energy Distribution of Starburst Galaxies. II. Control of the H II Region Parameters

Author

Dopita, Michael, Fischera, Joerg, Sutherland, Ralph, Kewley, Lisa, Tuffs, Richard J, Popescu, Cristina C, van Breugel, Wil, Groves, Brent, Leitherer, Claus, Dopita, Michael, Fischera, Joerg, Sutherland, Ralph, Kewley, Lisa, Tuffs, Richard J, Popescu, Cristina C, van Breugel, Wil, Groves, Brent, and Leitherer, Claus

Abstract

We examine, from a theoretical viewpoint, how the physical parameters of H II regions are controlled in both normal galaxies and in starburst environments. These parameters are the H II region luminosity function, the time-dependent size, the covering fraction of molecular clouds, the pressure in the ionized gas, and the ionization parameter. The factors that control them are the initial mass function (IMF) of the exciting stars, the cluster mass function, the metallicity, and the mean pressure in the surrounding interstellar medium. We investigate the sensitivity of the Ha luminosity to the IMF, and find that this can translate to more than a factor 2 variation in derived star formation rates. The molecular cloud dissipation timescale is estimated from a case study of M17 to be ∼1 Myr for this object. Based on H II luminosity function fitting for nearby galaxies, we suggest that the H II region cluster mass function is fitted by a lognormal form peaking at ∼ 100 M ⊙. The cluster mass function continues the stellar IMF to a higher mass regime. The pressure in the H II regions is controlled by the mechanical luminosity flux from the central cluster. Since this is closely related to the ionizing photon flux, we show that the ionization parameter is not a free variable, and that the diffuse ionized medium may be composed of many large, faint, and old H II regions. Finally, we derive theoretical probability distributions for the ionization parameter as a function of metallicity and compare these to those derived for SDSS galaxies.

Published
2006

124. Compact H II Regions: What Lies Within?

Author

Dopita, Michael, Fischera, Joerg, Crowley, Oliver, Sutherland, Ralph, Christiansen, Jessie, Tuffs, Richard J, Popescu, Cristina C, Groves, Brent, Kewley, Lisa, Dopita, Michael, Fischera, Joerg, Crowley, Oliver, Sutherland, Ralph, Christiansen, Jessie, Tuffs, Richard J, Popescu, Cristina C, Groves, Brent, and Kewley, Lisa

Abstract

This paper presents both stellar mass and H II region diagnostics based on dusty, radiation-pressure-dominated photoionization models for compact and ultracompact H II regions, and compares these with observational constraints. These models successfully reproduce the observed relationship between the density and the thickness of the ionized layer. The absorption of ionizing photons in the dusty ionized plasma makes denser ionized regions thinner than simple photoionization models would predict, improving the fit with the observations. The models provide a good fit to observed diagnostic plots involving ratios of infrared emission lines, all accessible with the IRS instrument of the Spitzer Space Telescope. These give the effective temperature to an accuracy of about 2500 K and the mass of the ionizing star to a precision of about ±30%. The S IV/S in ratio is sensitive to foreground extinction as well as to stellar effective temperature or mass. From this ratio, we determine that the mean extinction to observed compact H II regions is typically Av ∼ 30 mag. The electron temperature depends on the chemical abundances, the pressure, and the effective temperature of the exciting star. We use these models to rederive the slope of the Galactic abundance gradient, with the result that d log (O/H)/dRG = 0.06 ± 0.01 dex kpc-1, bringing the Galactic abundance gradient derived from compact H II regions into closer agreement with those based on other techniques. The shape of the far-IR SED of compact H II regions can be used to constrain the mean pressure or density in the H II region. The Spitzer MIPS instrument should be very helpful in this regard.

Published
2006

125. The [Ne III]/[Ne II] line ratio in NGC 253

Author

Popescu, Cristina C., Tuffs, Richard J., Devost, Daniel, Brandl, Bernhard R., Armus, L., Barry, D. J., Sloan, G. C., Charmandaris, Vassilis, Spoon, Henrik, Bernard-Salas, Jeronimo, Houck, James R., Popescu, Cristina C., Tuffs, Richard J., Devost, Daniel, Brandl, Bernhard R., Armus, L., Barry, D. J., Sloan, G. C., Charmandaris, Vassilis, Spoon, Henrik, Bernard-Salas, Jeronimo, and Houck, James R.

Abstract

We present results of the mapping of the nucleus of the starburst galaxy NGC 253 and its immediate surroundings using the Infrared Spectrograph on board the Spitzer Space Telescope. The map is centered on the nucleus of the galaxy and spans the inner 800 × 688 pc^2. We perform a brief investigation of the implications of these measurement on the properties of the star formation in this region using theories developed to explain the deficiency of massive stars in starbursts.

Published
2005

126. Galaxy And Mass Assembly (GAMA): Structural Investigation of Galaxies via Model Analysis

Author

Kelvin, Lee S., primary, Driver, Simon P., additional, Robotham, Aaron S. G., additional, Hill, David T., additional, Alpaslan, Mehmet, additional, Baldry, Ivan K., additional, Bamford, Steven P., additional, Bland-Hawthorn, Joss, additional, Brough, Sarah, additional, Graham, Alister W., additional, Häussler, Boris, additional, Hopkins, Andrew M., additional, Liske, Jochen, additional, Loveday, Jon, additional, Norberg, Peder, additional, Phillipps, Steven, additional, Popescu, Cristina C., additional, Prescott, Matthew, additional, Taylor, Edward N., additional, and Tuffs, Richard J., additional

Published
2012
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129. Modelling the spectral energy distribution of galaxies III. Attenuation of stellar light in spiral galaxies

Author

Tuffs, Richard J, Popescu, Cristina C, Volk, H J, Kylafis, Nikolaos, Dopita, Michael, Tuffs, Richard J, Popescu, Cristina C, Volk, H J, Kylafis, Nikolaos, and Dopita, Michael

Abstract

We present new calculations of the attenuation of stellar light from spiral galaxies using geometries for stars and dust which can reproduce the entire spectral energy distribution from the ultraviolet (UV) to the Far-infrared (FIR)/submillimeter (submm)

Published
2004

130. Text and Ideology: La dimension idéologique du texte

Author

van Noppen, Jean Pierre and Tuffs, Richard

Subjects
Analyse du discours des médias
Abstract

Numéro spécial de la Revue Belge de Philologie et d'Histoire, 73 (1995) n° 3., info:eu-repo/semantics/published

Published
1995

133. THE HUBBLE SPACE TELESCOPE WIDE FIELD CAMERA 3 EARLY RELEASE SCIENCE DATA: PANCHROMATIC FAINT OBJECT COUNTS FOR 0.2-2 μm WAVELENGTH

Author

Windhorst, Rogier A., primary, Cohen, Seth H., additional, Hathi, Nimish P., additional, McCarthy, Patrick J., additional, Ryan, Russell E., additional, Yan, Haojing, additional, Baldry, Ivan K., additional, Driver, Simon P., additional, Frogel, Jay A., additional, Hill, David T., additional, Kelvin, Lee S., additional, Koekemoer, Anton M., additional, Mechtley, Matt, additional, O'Connell, Robert W., additional, Robotham, Aaron S. G., additional, Rutkowski, Michael J., additional, Seibert, Mark, additional, Straughn, Amber N., additional, Tuffs, Richard J., additional, Balick, Bruce, additional, Bond, Howard E., additional, Bushouse, Howard, additional, Calzetti, Daniela, additional, Crockett, Mark, additional, Disney, Michael J., additional, Dopita, Michael A., additional, Hall, Donald N. B., additional, Holtzman, Jon A., additional, Kaviraj, Sugata, additional, Kimble, Randy A., additional, MacKenty, John W., additional, Mutchler, Max, additional, Paresce, Francesco, additional, Saha, Abihit, additional, Silk, Joseph I., additional, Trauger, John T., additional, Walker, Alistair R., additional, Whitmore, Bradley C., additional, and Young, Erick T., additional

Published
2011
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134. Galaxy and Mass Assembly: FUV, NUV, ugrizYJHK Petrosian, Kron and Sérsic photometry

Author

Hill, David T., primary, Kelvin, Lee S., additional, Driver, Simon P., additional, Robotham, Aaron S. G., additional, Cameron, Ewan, additional, Cross, Nicholas, additional, Andrae, Ellen, additional, Baldry, Ivan K., additional, Bamford, Steven P., additional, Bland-Hawthorn, Joss, additional, Brough, Sarah, additional, Conselice, Christopher J., additional, Dye, Simon, additional, Hopkins, Andrew M., additional, Liske, Jochen, additional, Loveday, Jon, additional, Norberg, Peder, additional, Peacock, John A., additional, Croom, Scott M., additional, Frenk, Carlos S., additional, Graham, Alister W., additional, Jones, D. Heath, additional, Kuijken, Konrad, additional, Madore, Barry F., additional, Nichol, Robert C., additional, Parkinson, Hannah R., additional, Phillipps, Steven, additional, Pimbblet, Kevin A., additional, Popescu, Cristina C., additional, Prescott, Matthew, additional, Seibert, Mark, additional, Sharp, Rob G., additional, Sutherland, Will J., additional, Thomas, Daniel, additional, Tuffs, Richard J., additional, and van Kampen, Elco, additional

Published
2010
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138. Dust in galaxies

Author

Popescu, Cristina C., primary, Tuffs, Richard J., additional, Mioc, Vasile, additional, Dumitrache, Cristiana, additional, and Popescu, Nedelia A., additional

Published
2008
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142. Compact HiiRegions: What Lies Within?

Author

Dopita, Michael A., primary, Fischera, Jorg, additional, Crowley, Oliver, additional, Sutherland, Ralph S., additional, Christiansen, Jessie, additional, Tuffs, Richard J., additional, Popescu, Cristina C., additional, Groves, Brent A., additional, and Kewley, Lisa J., additional

Published
2006
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145. A Comparative Study of the Spatial Distribution of Ultraviolet and Far-Infrared Fluxes from M101

Author

Popescu, Cristina C., primary, Tuffs, Richard J., additional, Madore, Barry F., additional, Gil de Paz, Armando, additional, Völk, Heinrich J., additional, Barlow, Tom, additional, Bianchi, Luciana, additional, Byun, Yong-Ik, additional, Donas, Jose, additional, Forster, Karl, additional, Friedman, Peter G., additional, Heckman, Timothy M., additional, Jelinsky, Patrick N., additional, Lee, Young-Wook, additional, Malina, Roger F., additional, Martin, D. Christopher, additional, Milliard, Bruno, additional, Morrissey, Patrick, additional, Neff, Susan G., additional, Rich, R. Michael, additional, Schiminovich, David, additional, Siegmund, Oswald H. W., additional, Small, Todd, additional, Szalay, Alex S., additional, Welsh, Barry Y., additional, and Wyder, Ted K., additional

Published
2005
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