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Start Over Author "Davies, J. I." Journal monthly notices of the royal astronomical society
133 results on '"Davies, J. I."'

1. The first maps of κd – the dust mass absorption coefficient – in nearby galaxies, with DustPedia

Author

Clark, C J R, primary, De Vis, P, additional, Baes, M, additional, Bianchi, S, additional, Casasola, V, additional, Cassarà, L P, additional, Davies, J I, additional, Dobbels, W, additional, Lianou, S, additional, De Looze, I, additional, Evans, R, additional, Galametz, M, additional, Galliano, F, additional, Jones, A P, additional, Madden, S C, additional, Mosenkov, A V, additional, Verstocken, S, additional, Viaene, S, additional, Xilouris, E M, additional, and Ysard, N, additional

Published
2019
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4. The first maps of κd – the dust mass absorption coefficient – in nearby galaxies, with DustPedia.

Author

Clark, C J R, De Vis, P, Baes, M, Bianchi, S, Casasola, V, Cassarà, L P, Davies, J I, Dobbels, W, Lianou, S, De Looze, I, Evans, R, Galametz, M, Galliano, F, Jones, A P, Madden, S C, Mosenkov, A V, Verstocken, S, Viaene, S, Xilouris, E M, and Ysard, N

Subjects
SPIRAL galaxies, ABSORPTION coefficients, KRIGING, DUST, GALAXIES, INTERSTELLAR medium
Abstract

The dust mass absorption coefficient, κd is the conversion function used to infer physical dust masses from observations of dust emission. However, it is notoriously poorly constrained, and it is highly uncertain how it varies, either between or within galaxies. Here we present the results of a proof-of-concept study, using the DustPedia data for two nearby face-on spiral galaxies M 74 (NGC 628) and M 83 (NGC 5236), to create the first ever maps of κd in galaxies. We determine κd using an empirical method that exploits the fact that the dust-to-metals ratio of the interstellar medium is constrained by direct measurements of the depletion of gas-phase metals. We apply this method pixel-by-pixel within M 74 and M 83, to create maps of κd. We also demonstrate a novel method of producing metallicity maps for galaxies with irregularly sampled measurements, using the machine learning technique of Gaussian process regression. We find strong evidence for significant variation in κd. We find values of κd at 500  |$\mu$| m spanning the range 0.11–0.25  |${\rm m^{2}\, kg^{-1}}$| in M 74, and 0.15–0.80  |${\rm m^{2}\, kg^{-1}}$| in M 83. Surprisingly, we find that κd shows a distinct inverse correlation with the local density of the interstellar medium. This inverse correlation is the opposite of what is predicted by standard dust models. However, we find this relationship to be robust against a large range of changes to our method – only the adoption of unphysical or highly unusual assumptions would be able to suppress it. [ABSTRACT FROM AUTHOR]

Published
2019
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7. H-ATLAS: the far-infrared properties of galaxies in and around the Coma cluster

Author

Fuller, C., primary, Davies, J. I., additional, Smith, M. W. L., additional, Valiante, E., additional, Eales, S., additional, Bourne, N., additional, Dunne, L., additional, Dye, S., additional, Furlanetto, C., additional, Ibar, E., additional, Ivison, R., additional, Maddox, S., additional, Sansom, A., additional, Michałowski, M. J., additional, and Davis, T., additional

Published
2016
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11. Kinematic clues to the origins of starless H I clouds: dark galaxies or tidal debris?

Author

Taylor, R., Davies, J. I., Jáchym, P., Keenan, O., Minchin, R. F., Palouš, J., Smith, R., and Wünsch, R.

Subjects
*GALAXIES, *CLOUDS, *DARK matter, *KINEMATICS, VIRGO Cluster
Abstract

Isolated H I clouds with no optical counterparts are often taken as evidence for galaxy-galaxy interactions, though an alternative hypothesis is that these are primordial 'dark galaxies' that have not formed stars. Similarly, certain kinematic features in H I streams are also controversial, sometimes taken as evidence of dark galaxies but also perhaps explicable as the result of harassment. We numerically model the passage of a galaxy through the gravitational field of cluster. The galaxy consists of smoothed particle hydrodynamics particles for the gas and N-bodies for the stars and dark matter, while the cluster includes the gravitational effects of substructure using 400 subhaloes (the effects of the intracluster medium are ignored). We find that harassment can indeed produce long H I streams and these streams can include kinematic features resembling dark galaxy candidates such as VIRGOHI21. We also show that apparent clouds with diameter <20 kpc and velocity widths <50 km s-1 are almost invariably produced in these simulations, making tidal debris a highly probable explanation. In contrast, we show that the frequency of isolated clouds of the same size but velocity width >100 km s-1 is negligible - making this a very unlikely explanation for the observed clouds in the Virgo cluster with these properties. [ABSTRACT FROM AUTHOR]

Published
2017
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13. A surprising consistency between the far-infrared galaxy luminosity functions of the field and Coma

Author

Hickinbottom, S., primary, Simpson, C. J., additional, James, P. A., additional, Ibar, E., additional, Carter, D., additional, Boselli, A., additional, Collins, C. A., additional, Davies, J. I., additional, Dunne, L., additional, Eales, S., additional, Fuller, C., additional, Mobasher, B., additional, Peletier, R. F., additional, Phillipps, S., additional, Smith, D. J. B., additional, Smith, R. J., additional, and Valentijn, E. A., additional

Published
2014
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14. The Herschel Fornax Cluster Survey II: FIR properties of optically selected Fornax cluster galaxies

Author

Fuller, C., primary, Davies, J. I., additional, Auld, R., additional, Smith, M. W. L., additional, Baes, M., additional, Bianchi, S., additional, Bocchio, M., additional, Boselli, A., additional, Clemens, M., additional, Davis, T. A., additional, De Looze, I., additional, di Serego Alighieri, S., additional, Grossi, M., additional, Hughes, T. M., additional, Viaene, S., additional, and Serra, P., additional

Published
2014
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15. PACS photometry of the Herschel Reference Survey – far-infrared/submillimetre colours as tracers of dust properties in nearby galaxies★

Author

Cortese, L., primary, Fritz, J., additional, Bianchi, S., additional, Boselli, A., additional, Ciesla, L., additional, Bendo, G. J., additional, Boquien, M., additional, Roussel, H., additional, Baes, M., additional, Buat, V., additional, Clemens, M., additional, Cooray, A., additional, Cormier, D., additional, Davies, J. I., additional, De Looze, I., additional, Eales, S. A., additional, Fuller, C., additional, Hunt, L. K., additional, Madden, S., additional, Munoz-Mateos, J., additional, Pappalardo, C., additional, Pierini, D., additional, Rémy-Ruyer, A., additional, Sauvage, M., additional, di Serego Alighieri, S., additional, Smith, M. W. L., additional, Spinoglio, L., additional, Vaccari, M., additional, and Vlahakis, C., additional

Published
2014
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16. The Herschel Virgo Cluster Survey – XVI. A cluster inventory★

Author

Davies, J. I., primary, Bianchi, S., additional, Baes, M., additional, Bendo, G. J., additional, Clemens, M., additional, De Looze, I., additional, Alighieri, S. di Serego, additional, Fritz, J., additional, Fuller, C., additional, Pappalardo, C., additional, Hughes, T. M., additional, Madden, S., additional, Smith, M. W. L., additional, Verstappen, J., additional, and Vlahakis, C., additional

Published
2014
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17. Attack of the flying snakes: formation of isolated HI clouds by fragmentation of long streams.

Author

Taylor, R., Davies, J. I., Jáchym, P., Keenan, O., Minchin, R. F., Palouš, J., Smith, R., and Wünsch, R.

Subjects
*SPACE debris, *COMPUTER simulation, *WATER ferns, *GALAXY clusters, *SPACE environment
Abstract

The existence of long (>100 kpc) HI streams and small (<20 kpc) free-floating HI clouds is well known. While the formation of the streams has been investigated extensively, and the isolated clouds are often purported to be interaction debris, little research has been done on the formation of optically dark HI clouds that are not part of a larger stream. One possibility is that such features result from the fragmentation of more extended streams, while another idea is that they are primordial, optically dark galaxies. We test the validity of the fragmentation scenario (via harassment) using numerical simulations. In order to compare our numerical models with observations, we present catalogues of both the known long HI streams (42 objects) and free-floating HI clouds suggested as dark galaxy candidates (51 objects). In particular, we investigate whether it is possible to form compact features with high velocity widths (>100 km s-1), similar to observed clouds which are otherwise intriguing dark galaxy candidates. We find that producing such features is possible but extremely unlikely, occurring no more than 0.2% of the time in our simulations. In contrast, we find that genuine dark galaxies could be extremely stable to harassment and remain detectable even after 5 Gyr in the cluster environment (with the important caveat that our simulations only explore harassment and do not yet include the intracluster medium, heating and cooling, or star formation). We also discuss the possibility that such objects could be the progenitors of recently discovered ultra diffuse galaxies. [ABSTRACT FROM AUTHOR]

Published
2016
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18. Probing the low surface brightness dwarf galaxy population of the virgo cluster.

Author

Davies, J. I., Davies, L. J. M., and Keenan, O. C.

Subjects
*SURFACE brightness (Astronomy), *DWARF galaxies, *GALACTIC magnitudes, *ASTRONOMICAL surveys, *DARK matter, VIRGO Cluster
Abstract

We have used data from the Next Generation Virgo Survey to investigate the dwarf galaxy population of the Virgo cluster. We mask and smooth the data, and then use the object detection algorithm SEXTRACTOR to make our initial dwarf galaxy selection. All candidates are then visually inspected to remove artefacts and duplicates. We derive parameters to best select low surface brightness galaxies using central surface brightness values of 22.5 ≤ μ0g ≤ 26.0 µg and exponential scale lengths of 3.0 ≤ h ≤ 10.0 arcsec to identify 443 cluster dwarf galaxies - 303 of which are new detections, with a surface density that decreases with radius from the cluster centre. We also apply our selection algorithm to 'background', non-cluster, fields and find zero detections. In combination, this leads us to believe that we have isolated a cluster dwarf galaxy population. The range of objects we detect is limited because smaller scale sized galaxies are confused with the background, while larger galaxies are split into numerous smaller objects by the detection algorithm. Combining our data with that from other surveys, we find a faint-end slope to the luminosity function of -1.35 ± 0.03, which is not significantly different to what has previously been found, but is a little steeper than the slope for field galaxies. There is no evidence for a faint-end slope steep enough to correspond with galaxy formation models, unless those models invoke either strong feedback processes or use warm dark matter. [ABSTRACT FROM AUTHOR]

Published
2016
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19. The Arecibo Galaxy Environment Survey - X. The structure of halo gas around M33.

Author

Keenan, O. C., Davies, J. I., Taylor, R., and Minchin, R. F.

Subjects
*ASTRONOMICAL observations, *DWARF galaxies, *GALAXY formation, *GALAXY clusters, *MAGELLANIC clouds
Abstract

As part of the H I Arecibo Galaxy Environment Survey (AGES), we have observed 5 × 4 deg of sky centred on M33, reaching a limiting column density of ~1.5 × 1017 cm-2 (line width of 10 km s-1 and resolution 3.5 arcmin). We particularly investigate the absence of optically detected dwarf galaxies around M33, something that is contrary to galaxy formation models. We identify 22 discrete H I clouds, 11 of which are new detections. The number of objects detected and their internal velocity dispersion distribution is consistent with expectations from standard galaxy formation models. However, the issue remains open as to whether the observed velocity dispersions can be used as a measure of the H I clouds total mass, i.e. are the velocities indicative of virialized structures or have they been influenced by tidal interactions with other structures in the Local Group? We identify one particularly interesting H I cloud, AGESM33-31, that has many of the characteristics of H I distributed in the disc of a galaxy, yet there is no known optical counterpart associated with it. This object has a total H I mass of 1.22 × 107 M⊙ and a diameter of 18 kpc if at the distance of M33 (DM33 = 840 kpc). However, we also find that there are numerous other H I clouds in this region of sky that have very similar velocities and so it is plausible that all these clouds are actually associated with debris from the Magellanic stream. [ABSTRACT FROM AUTHOR]

Published
2016
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20. The Arecibo Galaxy Environment Survey IX: the isolated galaxy sample.

Author

Minchin, R. F., Auld, R., Davies, J. I., Karachentsev, I. D., Keenan, O. C., Momjian, E., Rodriguez, R., Taber, T., and Taylor, R.

Subjects
GALAXIES, TIDAL stripping (Astrophysics), DENSITOMETERS, ASTRONOMY, DENSITY
Abstract

We have used the Arecibo L-band Feed Array (ALFA) to map three regions, each of 5 deg2, around the isolated galaxies NGC 1156, UGC 2082, and NGC 5523. In the vicinity of these galaxies we have detected two dwarf companions: one near UGC 2082, previously discovered by the Arecibo Legacy Fast ALFA (ALFALFA) survey, and one near NGC 1156, discovered by this project and reported in an earlier paper. This is significantly fewer than the 15.4+1.7 -1.5 that would be expected from the field HI mass function from ALFALFA or the 8.9±1.2 expected if the HI mass function from the Local Group applied in these regions. The number of dwarf companions detected is, however, consistent with a flat or declining HI mass function as seen by a previous, shallower, HI search for companions to isolated galaxies. We attribute this difference in HI mass functions to the different environments in which they are measured. This agrees with the general observation that lower ratios of dwarf to giant galaxies are found in lower density environments. [ABSTRACT FROM AUTHOR]

Published
2016
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21. The Herschel Virgo Cluster Survey – XII. FIR properties of optically selected Virgo cluster galaxies

Author

Auld, R., primary, Bianchi, S., additional, Smith, M. W. L., additional, Davies, J. I., additional, Bendo, G. J., additional, di Serego, S. Alighieri, additional, Cortese, L., additional, Baes, M., additional, Bomans, D. J., additional, Boquien, M., additional, Boselli, A., additional, Ciesla, L., additional, Clemens, M., additional, Corbelli, E., additional, De Looze, I., additional, Fritz, J., additional, Gavazzi, G., additional, Pappalardo, C., additional, Grossi, M., additional, Hunt, L. K., additional, Madden, S., additional, Magrini, L., additional, Pohlen, M., additional, Verstappen, J., additional, Vlahakis, C., additional, Xilouris, E. M., additional, and Zibetti, S., additional

Published
2012
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22. The Herschel Fornax Cluster Survey – I. The bright galaxy sample

Author

Davies, J. I., primary, Bianchi, S., additional, Baes, M., additional, Boselli, A., additional, Ciesla, L., additional, Clemens, M., additional, Davis, T. A., additional, De Looze, I., additional, Alighieri, S. di Serego, additional, Fuller, C., additional, Fritz, J., additional, Hunt, L. K., additional, Serra, P., additional, Smith, M. W. L., additional, Verstappen, J., additional, Vlahakis, C., additional, Xilouris, E. M., additional, Bomans, D., additional, Hughes, T., additional, Garcia-Appadoo, D., additional, and Madden, S., additional

Published
2012
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24. The gas-to-dust mass ratio of Centaurus A as seen by Herschel★

Author

Parkin, T. J., primary, Wilson, C. D., additional, Foyle, K., additional, Baes, M., additional, Bendo, G. J., additional, Boselli, A., additional, Boquien, M., additional, Cooray, A., additional, Cormier, D., additional, Davies, J. I., additional, Eales, S. A., additional, Galametz, M., additional, Gomez, H. L., additional, Lebouteiller, V., additional, Madden, S., additional, Mentuch, E., additional, Page, M. J., additional, Pohlen, M., additional, Remy, A., additional, Roussel, H., additional, Sauvage, M., additional, Smith, M. W. L., additional, and Spinoglio, L., additional

Published
2012
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25. The dust and gas properties of M83

Author

Foyle, K., primary, Wilson, C. D., additional, Mentuch, E., additional, Bendo, G., additional, Dariush, A., additional, Parkin, T., additional, Pohlen, M., additional, Sauvage, M., additional, Smith, M. W. L., additional, Roussel, H., additional, Baes, M., additional, Boquien, M., additional, Boselli, A., additional, Clements, D. L., additional, Cooray, A., additional, Davies, J. I., additional, Eales, S. A., additional, Madden, S., additional, Page, M. J., additional, and Spinoglio, L., additional

Published
2012
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26. Herschel observations of Cen A: stellar heating of two extragalactic dust clouds

Author

Auld, R., primary, Smith, M. W. L., additional, Bendo, G., additional, Pohlen, M., additional, Wilson, C., additional, Gomez, H., additional, Cortese, L., additional, Morganti, R., additional, Baes, M., additional, Boselli, A., additional, Cooray, A., additional, Davies, J. I., additional, Eales, S., additional, Elbaz, D., additional, Galametz, M., additional, Isaak, K., additional, Oosterloo, T., additional, Page, M., additional, Rigby, E., additional, Spinoglio, L., additional, and Struve, C., additional

Published
2012
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27. The Herschel Virgo Cluster Survey - VIII. The Bright Galaxy Sample★

Author

Davies, J. I., primary, Bianchi, S., additional, Cortese, L., additional, Auld, R., additional, Baes, M., additional, Bendo, G. J., additional, Boselli, A., additional, Ciesla, L., additional, Clemens, M., additional, Corbelli, E., additional, De Looze, I., additional, Alighieri, S. di Serego, additional, Fritz, J., additional, Gavazzi, G., additional, Pappalardo, C., additional, Grossi, M., additional, Hunt, L. K., additional, Madden, S., additional, Magrini, L., additional, Pohlen, M., additional, Smith, M. W. L., additional, Verstappen, J., additional, and Vlahakis, C., additional

Published
2011
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29. On the origin of M81 group extended dust emission

Author

Davies, J. I., primary, Wilson, C. D., additional, Auld, R., additional, Baes, M., additional, Barlow, M. J., additional, Bendo, G. J., additional, Bock, J. J., additional, Boselli, A., additional, Bradford, M., additional, Buat, V., additional, Castro-Rodriguez, N., additional, Chanial, P., additional, Charlot, S., additional, Ciesla, L., additional, Clements, D. L., additional, Cooray, A., additional, Cormier, D., additional, Cortese, L., additional, Dwek, E., additional, Eales, S. A., additional, Elbaz, D., additional, Galametz, M., additional, Galliano, F., additional, Gear, W. K., additional, Glenn, J., additional, Gomez, H. L., additional, Griffin, M., additional, Hony, S., additional, Isaak, K. G., additional, Levenson, L. R., additional, Lu, N., additional, Madden, S., additional, O'Halloran, B., additional, Okumura, K., additional, Oliver, S., additional, Page, M. J., additional, Panuzzo, P., additional, Papageorgiou, A., additional, Parkin, T. J., additional, Perez-Fournon, I., additional, Pohlen, M., additional, Rangwala, N., additional, Rigby, E. E., additional, Roussel, H., additional, Rykala, A., additional, Sacchi, N., additional, Sauvage, M., additional, Schulz, B., additional, Schirm, M. R. P., additional, Smith, M. W. L., additional, Spinoglio, L., additional, Stevens, J. A., additional, Srinivasan, S., additional, Symeonidis, M., additional, Trichas, M., additional, Vaccari, M., additional, Vigroux, L., additional, Wozniak, H., additional, Wright, G. S., additional, and Zeilinger, W. W., additional

Published
2010
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31. The Arecibo Galaxy Environment Survey - II. A H i view of the Abell cluster 1367 and its outskirts

Author

Cortese, L., primary, Minchin, R. F., additional, Auld, R. R., additional, Davies, J. I., additional, Catinella, B., additional, Momjian, E., additional, Rosenberg, J. L., additional, Taylor, R., additional, Gavazzi, G., additional, O'Neil, K., additional, Baes, M., additional, Boselli, A., additional, Bothun, G., additional, Koribalski, B., additional, Schneider, S., additional, and Driel, W. van, additional

Published
2008
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32. The UKIRT Infrared Deep Sky Survey Early Data Release

Author

Dye, S., primary, Warren, S. J., additional, Hambly, N. C., additional, Cross, N. J. G., additional, Hodgkin, S. T., additional, Irwin, M. J., additional, Lawrence, A., additional, Adamson, A. J., additional, Almaini, O., additional, Edge, A. C., additional, Hirst, P., additional, Jameson, R. F., additional, Lucas, P. W., additional, Van Breukelen, C., additional, Bryant, J., additional, Casali, M., additional, Collins, R. S., additional, Dalton, G. B., additional, Davies, J. I., additional, Davis, C. J., additional, Emerson, J. P., additional, Evans, D. W., additional, Foucaud, S., additional, Gonzales-Solares, E. A., additional, Hewett, P. C., additional, Kendall, T. R., additional, Kerr, T. H., additional, Leggett, S. K., additional, Lodieu, N., additional, Loveday, J., additional, Lewis, J. R., additional, Mann, R. G., additional, McMahon, R. G., additional, Mortlock, D. J., additional, Nakajima, Y., additional, Pinfield, D. J., additional, Rawlings, M. G., additional, Read, M. A., additional, Riello, M., additional, Sekiguchi, K., additional, Smith, A. J., additional, Sutorius, E. T. W., additional, Varricatt, W., additional, Walton, N. A., additional, and Weatherley, S. J., additional

Published
2006
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33. The Arecibo Galaxy Environment Survey: precursor observations of the NGC 628 group

Author

Auld, R., primary, Minchin, R. F., additional, Davies, J. I., additional, Catinella, B., additional, Van Driel, W., additional, Henning, P. A., additional, Linder, S., additional, Momjian, E., additional, Muller, E., additional, O'Neil, K., additional, Sabatini, S., additional, Schneider, S., additional, Bothun, G., additional, Cortese, L., additional, Disney, M., additional, Hoffman, G. L., additional, Putman, M., additional, Rosenberg, J. L., additional, Baes, M., additional, De Blok, W. J. G., additional, Boselli, A., additional, Brinks, E., additional, Brosch, N., additional, Irwin, J., additional, Karachentsev, I. D., additional, Kilborn, V. A., additional, Koribalski, B., additional, and Spekkens, K., additional

Published
2006
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