Friday, November 20, 2009

Interesting Astrophysics: Nov 16 to 20

Its a quiet week in terms of interesting papers and preprints. Given the small number of papers no added introduction to them is necessary.

Galaxies and Starbursts

On the interstellar medium and star formation demographics of galaxies in the local universe
Matthew S. Bothwell, Robert C. Kennicutt Jr, and Janice C. Lee, 2090, MNRAS, 400, 154
Full Text: HTML, PDF (Size: 1632K)

Photodissociation chemistry footprints in the Starburst galaxy NGC 253
Sergio Martin, J. Martin-Pintado, S. Viti, arXiv:0911.2673 [ps, pdf, other]
Comments: 32 pages, 4 figures, Published in ApJ
Journal-ref: 2009 ApJ 706 1323-1330

Origin(s) of the Highly Ionized High-Velocity Clouds Based on Their Distances
N. Lehner, J. C. Howk, arXiv:0911.2732 [ps, pdf, other]
Comments: Submitted to the ApJ Letters

Black Holes and AGN

Quasar Outflow Contribution to AGN Feedback: Observations of QSO SDSS J0838+2955
Maxwell Moe, Nahum Arav, Manuel A. Bautista, Kirk T. Korista, arXiv:0911.3332 [ps, pdf, other]
Comments: 28 pages, 7 figures, 4 tables, published in Astrophysical Journal
Journal-ref: 2009 ApJ 706 525-534

Their full abstract: "We present a detailed analysis of the Astrophysical Research Consortium 3.5 m telescope spectrum of QSO SDSS J0838+2955. The object shows three broad absorption line (BAL) systems at 22,000, 13,000, and 4900 km s^-1 blueshifted from the systemic redshift of z=2.043. Of particular interest is the lowest velocity system that displays absorption from low-ionization species such as Mg II, Al II, Si II, Si II*, Fe II and Fe II*. Accurate column densities were measured for all transitions in this lowest velocity BAL using an inhomogeneous absorber model. The ratio of column densities of Si II* and Fe II* with respect to their ground states gave an electron number density of log n_e (cm^-3) = 3.75 +/- 0.22 for the outflow. Photoionization modeling with careful regards to chemical abundances and the incident spectral energy distribution predicts an ionization parameter of log U_H = -1.93 +/- 0.21 and a hydrogen column density of log N_H (cm^-2) = 20.80 +/- 0.28. This places the outflow at 3.3+1.5-1.0 kpc from the central AGN. Assuming that the fraction of solid angle subtended by the outflow is 0.2, these values yield a kinetic luminosity of (4.5+3.1-1.8) x 10^45 erg s^-1, which is (1.4+1.1-0.6)% the bolometric luminosity of the QSO itself. Such large kinetic luminosity suggests that QSO outflows are a major contributor to AGN feedback mechanisms."

Numerical Astrophysics and Hydrodynamics

Turbulence modeling and the physics of the intra-cluster medium

L. Iapichino, A. Maier, W. Schmidt, J. C. Niemeyer, arXiv:0911.2629 [ps, pdf, other]
Comments: To appear in the proceedings of the "Invisible Universe International Conference"

Characterizing Magnetohydrodynamic Turbulence in the Small Magellanic Cloud
Blakesley Burkhart, Snezana Stanimirovic, Alex Lazarian, Grzegorz Kowal, arXiv:0911.3652 [ps, pdf, other]

Stars, Supernovae and Planets

A Feature Movie of SiO Emission 20-100 AU from the Massive Young Stellar Object Orion Source I
L. D. Matthews, L. J. Greenhill, C. Goddi, C. J. Chandler, E. M. L. Humphreys, M. Kunz, rXiv:0911.2473 [pdf, other]

Comments: Accepted to ApJ (January 2010); a full resolution version along with two accompanying GIF movies may be found at this http URL

An Unusually Fast-Evolving Supernova
Dovi Poznanski, Ryan Chornock, Peter E. Nugent, Joshua S. Bloom, Mohan Ganeshalingam, Douglas C. Leonard, Weidong Li, Rollin C. Thomas, arXiv:0911.2699 [pdf, other]
Comments: Science in press, first published online on Nov 5, 2009 in Science Express. Includes supporting online materia

The low-mass Initial Mass Function in the 30 Doradus starburst cluster
M. Andersen, H. Zinnecker, A. Moneti, M. J. McCaughrean, B. Brandl, W. Brandner, G. Meylan, D. Hunter, arXiv:0911.2755 [ps, pdf, other]
Comments: Accepted in ApJ. Abstract abridged

How Common are Extrasolar, Late Heavy Bombardments?
Mark Booth, Mark C. Wyatt, Alessandro Morbidelli, Amaya Moro-Martín, Harold F. Levison, arXiv:0911.3271 [ps, pdf, other]
Comments: 2 pages, 1 figure. Contribution to the conference proceedings for 'Pathways towards habitable planets'


A Vigorous Explorer Program
Martin Elvis, et al, arXiv:0911.3383 [pdf]
Comments: 18 pages, no figures. An Activities/Program White Paper submitted to the Astro2010 NAS/NRC Decadal Review of Astronomy and Astrophysics

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