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Search Results: 1 - 10 of 167606 matches for " E. Mentuch "
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A simple connection between the near- and mid-infrared emission of galaxies and their star-formation rates
Erin Mentuch,Roberto Abraham,Stefano Zibetti
Physics , 2010, DOI: 10.1088/0004-637X/725/2/1971
Abstract: We have measured the near-infrared colors and the fluxes of individual pixels in 68 galaxies common to the Spitzer Infrared Nearby Galaxies Survey and the Large Galaxy Atlas Survey. Each galaxy was separated into regions of increasingly red near-infrared colors. In the absence of dust extinction and other non-stellar emission, stellar populations are shown to have relatively constant NIR colors, independent of age. In regions of high star formation, the average intensity of pixels in red-excess regions (at 1.25, 3.6, 4.5, 5.6, 8.0 and 24 micron) scales linearly with the intrinsic intensity of Halpha emission, and thus with the star-formation rate within the pixel. This suggests that most NIR-excess regions are not red because their light is being depleted by absorption. Instead, they are red because additional infrared light is being contributed by a process linked to star-formation. This is surprising because the shorter wavelength bands in our study (1.25 micron-5.6 micron) do not probe emission from cold (10-20 K) and warm (50-100 K) dust associated with star-formation in molecular clouds. However, emission from hot dust (700-1000 K) and/or Polycyclic Aromatic Hydrocarbon molecules can explain the additional emission seen at the shorter wavelengths in our study. The contribution from hot dust and/or PAH emission at 2-5micron and PAH emission at 5.6 and 8.0 micron scales linearly with warm dust emission at 24 micron and the intrinsic Halpha emission. Since both are tied to the star-formation rate, our analysis shows that the NIR excess continuum emission and PAH emission at ~1-8 micron can be added to spectral energy distribution models in a very straight-forward way, by simply adding an additional component to the models that scales linearly with star-formation rate.
A near-infrared excess in the continuum of high-redshift galaxies: a tracer of star formation and circumstellar disks?
E. Mentuch,R. G. Abraham,K. Glazebrook,P. J. McCarthy,H. Yan,D. V. O'Donnell,D. Le Borgne,S. Savaglio,D. Crampton,R. Murowinski,S. Juneau,R. G. Carlberg,I. Jorgensen,K. Roth,H. Chen,R. O. Marzke
Physics , 2009, DOI: 10.1088/0004-637X/706/2/1020
Abstract: A broad continuum excess in the near-infrared, peaking in the rest-frame at 2-5 micron, is detected in a spectroscopic sample of 88 galaxies at 0.5
Measuring star formation in high-z massive galaxies: A mid-infrared to submillimeter study of the GOODS NICMOS Survey sample
Marco P. Viero,Lorenzo Moncelsi,Erin Mentuch,Fernando Buitrago,Amanda. E. Bauer,Edward L. Chapin,Christopher J. Conselice,Mark J. Devlin,Mark Halpern,Gaelen Marsden,Calvin B. Netterfield,Enzo Pascale,Pablo. G. Pérez-González,Marie Rex,Douglas Scott,Matthew W. L. Smith,Matthew D. P. Truch,Ignacio Trujillo,Donald V. Wiebe
Physics , 2010, DOI: 10.1111/j.1365-2966.2012.20456.x
Abstract: We present measurements of the mean mid-infrared-to-submillimeter flux densities of massive (M\ast \approx 2 \times 10^11 Msun) galaxies at redshifts 1.7 < z < 2.9, obtained by stacking positions of known objects taken from the GOODS NICMOS Survey (GNS) catalog on maps: at 24 {\mu}m (Spitzer/MIPS); 70, 100, and 160{\mu}m (Herschel/PACS); 250, 350, 500{\mu}m (BLAST); and 870{\mu}m (LABOCA). A modified blackbody spectrum fit to the stacked flux densities indicates a median [interquartile] star-formation rate of SFR = 63 [48, 81] Msun yr^-1 . We note that not properly accounting for correlations between bands when fitting stacked data can significantly bias the result. The galaxies are divided into two groups, disk-like and spheroid-like, according to their Sersic indices, n. We find evidence that most of the star formation is occurring in n \leq 2 (disk-like) galaxies, with median [interquartile] SFR = 122 [100,150] Msun yr^-1, while there are indications that the n > 2 (spheroid-like) population may be forming stars at a median [interquartile] SFR = 14 [9,20] Msun yr^-1, if at all. Finally, we show that star formation is a plausible mechanism for size evolution in this population as a whole, but find only marginal evidence that it is what drives the expansion of the spheroid-like galaxies.
Investigations of dust heating in M81, M83, and NGC 2403 with the Herschel Space Observatory
G. J. Bendo,A. Boselli,A. Dariush,M. Pohlen,H. Roussel,M. Sauvage,M. W. L. Smith,C. D. Wilson,M. Baes,A. Cooray,D. L. Clements,L. Cortese,K. Foyle,M. Galametz,H. L. Gomez,V. Lebouteiller,N. Lu,S. C. Madden,E. Mentuch,B. O'Halloran,M. J. Page,A. Remy,B. Schulz,L. Spinoglio
Physics , 2011, DOI: 10.1111/j.1365-2966.2011.19735.x
Abstract: We use Spitzer Space Telescope and Herschel Space Observatory far-infrared data along with ground-based optical and near-infrared data to understand how dust heating in the nearby face-on spiral galaxies M81, M83, and NGC 2403 is affected by the starlight from all stars and by the radiation from star forming regions. We find that 70/160 micron surface brightness ratios tend to be more strongly influenced by star forming regions. However, the 250/350 micron and 350/500 micron surface brightness ratios are more strongly affected by the light from the total stellar populations, suggesting that the dust emission at >250 microns originates predominantly from a component that is colder than the dust seen at <160 microns and that is relatively unaffected by star formation activity. We conclude by discussing the implications of this for modelling the spectral energy distributions of both nearby and more distant galaxies and for using far-infrared dust emission to trace star formation.
Cold dust but warm gas in the unusual elliptical galaxy NGC 4125
C. D. Wilson,A. Cridland,K. Foyle,T. J. Parkin,E. Mentuch Cooper,H. Roussel,M. Sauvage,M. W. L. Smith,M. Baes,G. Bendo,M. Boquien,A. Boselli,L. Ciesla,D. L. Clements,A. Cooray,I. De Looze,M. Galametz,W. Gear,V. Lebouteiller,S. Madden,M. Pereira-Santaella,A. Remy-Ruyer
Physics , 2013, DOI: 10.1088/2041-8205/776/2/L30
Abstract: Data from the Herschel Space Observatory have revealed an unusual elliptical galaxy, NGC 4125, which has strong and extended submillimeter emission from cold dust but only very strict upper limits to its CO and HI emission. Depending on the dust emissivity, the total dust mass is 2-5x10^6 Msun. While the neutral gas-to-dust mass ratio is extremely low (< 12-30), including the ionized gas traced by [CII] emission raises this limit to < 39-100. The dust emission follows a similar r^{1/4} profile to the stellar light and the dust to stellar mass ratio is towards the high end of what is found in nearby elliptical galaxies. We suggest that NGC 4125 is currently in an unusual phase where evolved stars produced in a merger-triggered burst of star formation are pumping large amounts of gas and dust into the interstellar medium. In this scenario, the low neutral gas-to-dust mass ratio is explained by the gas being heated to temperatures >= 10^4 K faster than the dust is evaporated. If galaxies like NGC 4125, where the far-infrared emission does not trace neutral gas in the usual manner, are common at higher redshift, this could have significant implications for our understanding of high redshift galaxies and galaxy evolution.
The gas-to-dust mass ratio of Centaurus A as seen by Herschel
T. J. Parkin,C. D. Wilson,K. Foyle,M. Baes,G. J. Bendo,A. Boselli,M. Boquien,A. Cooray,D. Cormier,J. I. Davies,S. A. Eales,M. Galametz,H. L. Gomez,V. Lebouteiller,S. Madden,E. Mentuch,M. J. Page,M. Pohlen,A. Remy,H. Roussel,M. Sauvage,M. W. L. Smith,L. Spinoglio
Physics , 2012, DOI: 10.1111/j.1365-2966.2012.20778.x
Abstract: We present photometry of the nearby galaxy NGC 5128 (Centaurus A) observed with the PACS and SPIRE instruments on board the Herschel Space Observatory, at 70, 160, 250, 350 and 500 {\mu}m, as well as new CO J = 3-2 observations taken with the HARP-B instrument on the JCMT. Using a single component modified blackbody, we model the dust spectral energy distribution within the disk of the galaxy using all five Herschel wavebands, and find dust temperatures of ~30 K towards the centre of the disk and a smoothly decreasing trend to ~20 K with increasing radius. We find a total dust mass of (1.59 \pm 0.05) \times 10^7 M\odot, and a total gas mass of (2.7 \pm 0.2) \times 10^9 M\odot. The average gas-to-dust mass ratio is 103 \pm 8 but we find an interesting increase in this ratio to approximately 275 toward the centre of Cen A. We discuss several possible physical processes that may be causing this effect, including dust sputtering, jet entrainment and systematic variables such as the XCO factor. Dust sputtering by X-rays originating in the AGN or the removal of dust by the jets are our most favoured explanations.
The Dust & Gas Properties of M83
K. Foyle,C. D. Wilson,E. Mentuch,G. Bendo,A. Dariush,T. Parkin,M. Pohlen,M. Sauvage,M. W. L. Smith,H. Roussel,M. Baes,M. Boquien,A. Boselli,D. L. Clements,A. Cooray,J. I. Davies,S. A. Eales,S. Madden,M. J. Page,Spinoglio
Physics , 2012, DOI: 10.1111/j.1365-2966.2012.20520.x
Abstract: We examine the dust and gas properties of the nearby, barred galaxy M83, which is part of the Very Nearby Galaxy Survey. Using images from the PACS and SPIRE instruments of Herschel, we examine the dust temperature and dust mass surface density distribution. We find that the nuclear, bar and spiral arm regions exhibit higher dust temperatures and masses compared to interarm regions. However, the distribution of dust temperature and mass are not spatially coincident. Assuming a trailing spiral structure, the dust temperature peaks in the spiral arms lie ahead of the dust surface density peaks. The dust mass surface density correlates well with the distribution of molecular gas as traced by CO (J=3-2) images (JCMT) and the star formation rate as traced by H?2 with a correction for obscured star formation using 24 micron emission. Using HI images from THINGS to trace the atomic gas component, we make total gas mass surface density maps and calculate the gas-to-dust ratio. We find a mean gas-to-dust ratio of 84 \pm 4 with higher values in the inner region assuming a constant CO-to-H2 conversion factor. We also examine the gas-to-dust ratio using CO-to-H2 conversion factor that varies with metallicity.
The Herschel Reference Survey: Dust in Early-Type Galaxies and Across the Hubble Sequence
M. W. L. Smith,H. L. Gomez,S. A. Eales,L. Ciesla,A. Boselli,L. Cortese,G. J. Bendo,M. Baes,S. Bianchi,M. Clemens,D. L. Clements,A. R. Cooray,J. I. Davies,I. de Looze,S. di Serego Alighieri,J. Fritz,G. Gavazzi,W. K. Gear,S. Madden,E. Mentuch,P. Panuzzo,M. Pohlen,L. Spinoglio,J. Verstappen,C. Vlahakis,C. D. Wilson,E. M. Xilouris
Physics , 2011, DOI: 10.1088/0004-637X/748/2/123
Abstract: We present Herschel observations of 62 Early-Type Galaxies (ETGs), including 39 galaxies morphologically classified as S0+S0a and 23 galaxies classified as ellipticals using SPIRE at 250, 350 and 500 microns (and PACS 100 and 160 microns for 19 sources) as part of the volume-limited Herschel Reference Survey. We detect dust emission in 24% of the ellipticals and 62% of the S0s. The mean temperature of the dust is 23.9+/-0.8 K, warmer than that found for late-type galaxies in the Virgo Cluster. Including the non-detections, the mean dust mass is log(Mdust) = 5.9+/-0.1 and 5.2+/-0.1 Msun for the S0s and elliptical galaxies respectively. The mean dust-to-stellar mass is log(Mdust/Mstar) = -4.4+/-0.1 (S0s) and -5.8+/-0.1 (ellipticals). Virtually all the galaxies lie close to the red sequence yet the large number of detections of cool dust, the gas-to-dust ratios and the ratios of far-infrared to radio emission all suggest that many ETGs contain a cool interstellar medium similar to that in late-type galaxies. The mean dust-to-stellar mass ratio for S0s is approximatly a factor of ten less than for early-type spirals and the sizes of the dust sources in the S0s are also much smaller. We show that the difference cannot be explained by either the different bulge-to-disk ratios or environmental effects such as ram-pressure stripping. The wide range in the dust-to-stellar mass ratio for ETGs and the lack of a correlation between dust mass and optical luminosity suggest that much of the dust in the ETGs detected by Herschel has been acquired as the result of gravitational interactions; these interactions are unlikely to have had a major effect on the stellar masses of the ETGs. The Herschel observations tentatively suggest that in the most massive ETGs, the mass of the interstellar medium is unconnected to the evolution of the stellar populations.
The Herschel Exploitation of Local Galaxy Andromeda (HELGA) II: Dust and Gas in Andromeda
M. W. L. Smith,S. A. Eales,H. L. Gomez,J. Roman Duval,J. Fritz,R. Braun,M. Baes,G. J. Bendo,J. A. D. L Blommaert,M. Boquien,A. Boselli,D. L. Clements,A. R. Cooray,L. Cortese,I. de Looze,G. P. Ford,W. K. Gear,G. Gentile,K. D. Gordon,J. Kirk,V. Lebouteiller,S. Madden,E. Mentuch,B. O'Halloran,M. J. Page,B. Schulz,L. Spinoglio,J. Verstappen,C. D. Wilson
Physics , 2012, DOI: 10.1088/0004-637X/756/1/40
Abstract: We present an analysis of the dust and gas in Andromeda, using Herschel images sampling the entire far-infrared peak. We fit a modified-blackbody model to ~4000 quasi-independent pixels with spatial resolution of ~140pc and find that a variable dust-emissivity index (beta) is required to fit the data. We find no significant long-wavelength excess above this model suggesting there is no cold dust component. We show that the gas-to-dust ratio varies radially, increasing from ~20 in the center to ~70 in the star-forming ring at 10kpc, consistent with the metallicity gradient. In the 10kpc ring the average beta is ~1.9, in good agreement with values determined for the Milky Way (MW). However, in contrast to the MW, we find significant radial variations in beta, which increases from 1.9 at 10kpc to ~2.5 at a radius of 3.1kpc and then decreases to 1.7 in the center. The dust temperature is fairly constant in the 10kpc ring (ranging from 17-20K), but increases strongly in the bulge to ~30K. Within 3.1kpc we find the dust temperature is highly correlated with the 3.6 micron flux, suggesting the general stellar population in the bulge is the dominant source of dust heating there. At larger radii, there is a weak correlation between the star formation rate and dust temperature. We find no evidence for 'dark gas' in M31 in contrast to recent results for the MW. Finally, we obtained an estimate of the CO X-factor by minimising the dispersion in the gas-to-dust ratio, obtaining a value of (1.9+/-0.4)x10^20 cm^-2 [K kms^-1]^-1.
The Herschel Stripe 82 Survey (HerS): Maps and Early Catalog
M. P. Viero,V. Asboth,I. G. Roseboom,L. Moncelsi,G. Marsden,E. Mentuch Cooper,M. Zemcov,G. Addison,A. J. Baker,A. Beelen,J. Bock,C. Bridge,A. Conley,M. J. Devlin,O. Doré,D. Farrah,S. Finkelstein,A. Font-Ribera,J. E. Geach,K. Gebhardt,A. Gill,J. Glenn,A. Hajian,M. Halpern,S. Jogee,P. Kurczynski,A. Lapi,M. Negrello,S. J. Oliver,C. Papovich,R. Quadri,N. Ross,D. Scott,B. Schulz,R. Somerville,D. N. Spergel,J. D. Vieira,L. Wang,R. Wechsler
Physics , 2013, DOI: 10.1088/0067-0049/210/2/22
Abstract: We present the first set of maps and band-merged catalog from the Herschel Stripe 82 Survey (HerS). Observations at 250, 350, and 500 micron were taken with the Spectral and Photometric Imaging Receiver (SPIRE) instrument aboard the Herschel Space Observatory. HerS covers 79 deg$^2$ along the SDSS Stripe 82 to a depth of 13.0, 12.9, and 14.8 mJy beam$^{-1}$ (including confusion) at 250, 350, and 500 micron, respectively. HerS was designed to measure correlations with external tracers of the dark matter density field --- either point-like (i.e., galaxies selected from radio to X-ray) or extended (i.e., clusters and gravitational lensing) --- in order to measure the bias and redshift distribution of intensities of infrared-emitting dusty star-forming galaxies and AGN. By locating HeRS in Stripe 82, we maximize the overlap with available and upcoming cosmological surveys. The band-merged catalog contains 3.3x10$^4$ sources detected at a significance of >3 $\sigma$ (including confusion noise). The maps and catalog are available at http://www.astro.caltech.edu/hers/
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