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Physical Sciences and Mathematics Commons

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Series

Astrophysics and Astronomy

1996

University of Massachusetts Amherst

Articles 1 - 4 of 4

Full-Text Articles in Physical Sciences and Mathematics

The Fate Of Cannibalized Fundamental-Plane Ellipticals, Martin D. Weinberg Jul 1996

The Fate Of Cannibalized Fundamental-Plane Ellipticals, Martin D. Weinberg

Astronomy Department Faculty Publication Series

Evolution and disruption of galaxies orbiting in the gravitational field of a larger cluster galaxy are driven by three coupled mechanisms: 1) the heating due to its time dependent motion in the primary; 2) mass loss due to the tidal strain field; and 3) orbital decay. Previous work demonstrated that tidal heating is effective well inside the impulse approximation limit. Not only does the overall energy increase over previous predictions, but the work is done deep inside the secondary galaxy, e.g. at or inside the half mass radius in most cases. Here, these ideas applied to cannibalization of elliptical galaxies …


Ricci Tensor Of Diagonal Metric, K. Z. Win Feb 1996

Ricci Tensor Of Diagonal Metric, K. Z. Win

Astronomy Department Faculty Publication Series

Efficient formulae of Ricci tensor for an arbitrary diagonal metric are presented.


The Dynamics Of The Galatic Bar, Martin D. Weinberg Jan 1996

The Dynamics Of The Galatic Bar, Martin D. Weinberg

Astronomy Department Faculty Publication Series

No abstract provided.


The Global Rate And Efficiency Of Star Formation In Spiral Galaxies As A Function Of Morphology And Environment, Judith S. Young, Lori Allen, Jeffrey D.P. Kenney, Amy Lesser, Brooks Rownd Jan 1996

The Global Rate And Efficiency Of Star Formation In Spiral Galaxies As A Function Of Morphology And Environment, Judith S. Young, Lori Allen, Jeffrey D.P. Kenney, Amy Lesser, Brooks Rownd

Astronomy Department Faculty Publication Series

CCD images of Hα and R-band emission in 120 spiral galaxies were obtained using the now-retired No. 1-0.9 m telescope of Kitt Peak National Observatory. These images were used to derive the distribution and total flux of continuum-subtracted Hα line emission, and therefore the Hα surface brightnesses and high mass star formation rates in these galaxies. We find a small but significant variation in the mean Hα surface brightness for spiral galaxies along the Hubble sequence; the Sd-Ir galaxies exhibit a mean Hα surface brightness 1.4 times higher than the Sbc-Scd galaxies, and 2-3 times higher than the Sa-Sb galaxies. …