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Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
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- Keyword
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- Galaxies: spiral (5)
- Galaxies: ISM (4)
- Dust, extinction (3)
- Galaxies: structure (3)
- Galaxies: evolution (2)
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- Galaxies: halos (2)
- ISM: structure (2)
- Infrared: ISM (2)
- Infrared: galaxies (2)
- Black holes (1)
- Bose– Einstein condensate (1)
- Composite bosons (1)
- Degenerate matter (1)
- Ferminon condensation (1)
- Galaxies: fundamental parameters (1)
- Galaxies: individual (NGC 4244) (1)
- Galaxies: individual (NGC 925, NGC 2841, NGC 3198, NGC 3351, NGC 3621, NGC 3627, NGC 4321, NGC 4536, NGC 4559, NGC 5491, NGC 6946, NGC 7331) (1)
- Galaxies: stellar content (1)
- Neutron stars (1)
- Stellar equilibrium (1)
- Steller collapse (1)
Articles 1 - 6 of 6
Full-Text Articles in Physical Sciences and Mathematics
The Opacity Of Spiral Galaxy Disks. Viii. Structure Of The Cold Ism., Benne W. Holwerda, B. Draine, K. D. Gordon, R. A. Gonzalez, D. Calzetti, M. Thornley, B. Buckalew, Ronald J. Allen, P C. Van Der Kruit
The Opacity Of Spiral Galaxy Disks. Viii. Structure Of The Cold Ism., Benne W. Holwerda, B. Draine, K. D. Gordon, R. A. Gonzalez, D. Calzetti, M. Thornley, B. Buckalew, Ronald J. Allen, P C. Van Der Kruit
Faculty Scholarship
The quantity of dust in a spiral disk can be estimated using the dust’s typical emission or the extinction of a known source. In this paper we compare two techniques, one based on emission and one on absorption, applied to sections of 14 disk galaxies. The two measurements reflect, respectively, the average and apparent optical depth of a disk section. Hence, they depend differently on the average number and optical depth of ISM structures in the disk. The small-scale geometry of the cold ISM is critical for accurate models of the overall energy budget of spiral disks. ISM geometry, relative …
Spiral Disk Opacity From Occulting Galaxy Pairs In The Sloan Digital Sky Survey., Benne W. Holwerda, W. C. Keel, A. Bolton
Spiral Disk Opacity From Occulting Galaxy Pairs In The Sloan Digital Sky Survey., Benne W. Holwerda, W. C. Keel, A. Bolton
Faculty Scholarship
A spiral galaxy partially overlapping a more distant elliptical offers a unique opportunity to measure the dust extinction in the foreground spiral. From the Sloan Digital Sky Survey (SDSS) DR4 spectroscopic sample, we selected 83 occulting galaxy pairs and measured disk opacity over the redshift range z ¼ 0:0Y0:2 with the goal of determining the recent evolution of disk dust opacity. The enrichment of the ISM changes over the lifetime of a disk, and it is reasonable to expect the dust extinction properties of spiral disks as a whole to change over their lifetime. When they do, the change will …
Gaps In The Cloud Cover? : Comparing Extinction Measures In Spiral Disks., Benne W. Holwerda, M. Meyer, M. W. Regan, D. Calzetti, K. D. Gordon, J. D. Smith, D. Dale, C. W. Engelbracht, T. Jarrett, M. Thornley, C. Bot, B. Buckalew, R. C. Kennicutt, R. A. Gonzalez
Gaps In The Cloud Cover? : Comparing Extinction Measures In Spiral Disks., Benne W. Holwerda, M. Meyer, M. W. Regan, D. Calzetti, K. D. Gordon, J. D. Smith, D. Dale, C. W. Engelbracht, T. Jarrett, M. Thornley, C. Bot, B. Buckalew, R. C. Kennicutt, R. A. Gonzalez
Faculty Scholarship
Dust in galaxies can be mapped either by the FIR/submillimeter emission, the optical or infrared reddening of starlight, or the extinction of a known background source. We compare two dust extinction measurements for a set of 15 sections in 13 nearby galaxies to determine the scale of the dusty interstellar medium ( ISM ) responsible for disk opacity: one using stellar reddening and the other a known background source. In our earlier papers, we presented extinction measurements of 29 galaxies, based on calibrated counts of distant background objects identified though foreground disks in Hubble Space Telescope WFPC2 images. For the …
Stellar Populations Across The Ngc 4244 Truncated Galactic Disk., Roelof De Jong, A. C. Seth, D. Radburn-Smith, E. F. Bell, T. M. Brown, J. S. Bullock, S. Courteau, J. J. Dalcanton, H. C. Ferguson, P. Goudfrooij, S. Holfeltz, Benne W. Holwerda, C. Purcell, J. Sick, D. B. Zucker
Stellar Populations Across The Ngc 4244 Truncated Galactic Disk., Roelof De Jong, A. C. Seth, D. Radburn-Smith, E. F. Bell, T. M. Brown, J. S. Bullock, S. Courteau, J. J. Dalcanton, H. C. Ferguson, P. Goudfrooij, S. Holfeltz, Benne W. Holwerda, C. Purcell, J. Sick, D. B. Zucker
Faculty Scholarship
We use the Hubble Space Telescope ACS to study the resolved stellar populations of the nearby, nearly edgeon galaxy NGC 4244 across its outer disk surface density break. The stellar photometry allows us to study the distribution of different stellar populations and reach very low equivalent surface brightnesses. We find that the break occurs at the same radius for young, intermediate-age, and old stars. The stellar density beyond the break drops sharply by a factor of at least 600 in 5 kpc. The break occurs at the same radius independent of height above the disk, but is sharpest in the …
A Dust Component ~2 Kpc Above The Plane In Ngc 891., P. Kamphuis, Benne W. Holwerda, R. J. Allen, R. F. Peletier, P. C. Van Der Kruit
A Dust Component ~2 Kpc Above The Plane In Ngc 891., P. Kamphuis, Benne W. Holwerda, R. J. Allen, R. F. Peletier, P. C. Van Der Kruit
Faculty Scholarship
Context.The halo of NGC 891 has been the subject of studies for more than a decade. One of its most striking features is the large asymmetry in H emission. In this letter, we will take a quantitative look at this asymmetry at different wavelengths for the first time.
Aims.We suggest that NGC 891 is intrinsically almost symmetric and the large asymmetry in H emission is mostly due to dust attenuation. We will quantify the additional optical depth needed to cause the observed asymmetry in this model.
Methods.By comparing large strips on the North East side of the …
Condensates In The Cosmos: Quantum Stabilization Of The Collapse Of Relativistic Degenerate Stars To Black Holes [Post-Print], Mark P. Silverman
Condensates In The Cosmos: Quantum Stabilization Of The Collapse Of Relativistic Degenerate Stars To Black Holes [Post-Print], Mark P. Silverman
Faculty Scholarship
According to prevailing theory, relativistic degenerate stars with masses beyond the Chandrasekhar and Oppenheimer–Volkoff (OV) limits cannot achieve hydrostatic equilibrium through either electron or neutron degeneracy pressure and must collapse to form stellar black holes. In such end states, all matter and energy within the Schwarzschild horizon descend into a central singularity. Avoidance of this fate is a hoped-for outcome of the quantization of gravity, an as-yet incomplete undertaking. Recent studies, however, suggest the possibility that known quantum processes may intervene to arrest complete collapse, thereby leading to equilibrium states of macroscopic size and finite density. I describe here one …