Friday, June 05, 2009

Interesting Astrophysics: Jun 01 - Jun 05

A mixed bag this week. Of particular note are the two papers on the ever-interesting M82, a paper on Lyα-driven supershell acceleration, problems with the clumpfind algorithm, and a paper discussing the historical perception of astronomers within society.

Galaxies and Starbursts

M82 as a Galaxy: Morphology and Stellar Content of the Disk and Halo
Y. Divakara Mayya, Luis Carrasco, arXiv:0906.0757 [ps, pdf, other]
Comments: 12 pages, To appear in the proceedings of "A Long Walk Through Astronomy: A Celebration of Luis Carrasco's 60th Birthday", Huatulco, Mexico, October 2008, ed. E. Recillas, L. Aguilar, A. Luna, and J.R. Valdes; RevMexAA (Serie de Conferencias)

Age and Extinction of the Ultraviolet Emitting Regions in M82
L.H. Rodriguez-Merino, D. Rosa-Gonzalez, Y.D. Mayya, L. Carrasco, A. Luna, R. Romano, arXiv:0906.0759 [ps, pdf, other]
Comments: 6 pages, To appear in the proceedings of "A Long Walk Through Astronomy: A Celebration of Luis Carrasco's 60th Birthday", Huatulco, Mexico, October 2008, ed. E. Recillas, L. Aguilar, A. Luna, and J.R. Valdes; RevMexAA (Serie de Conferencias)

Strong PAH Emission from z~2 ULIRGs
Vandana Desai, B. T. Soifer, Arjun Dey, Emeric Le Floc'h, Lee Armus, Kate Brand, Michael J. I. Brown, Mark Brodwin, Buell T. Jannuzi, James R. Houck, Daniel W. Weedman, Matthew L. N. Ashby, Anthony Gonzalez, Jiasheng Huang, Howard A. Smith, Harry Teplitz, Steve P. Willner, Jason Melbourne, arXiv:0905.4274 [ps, pdf, other]
Comments: accepted for publication in ApJ

Starburst and cirrus models for submillimeter galaxies
Andreas Efstathiou, Ralf Siebenmorgen, arXiv:0906.0446 [ps, pdf, other]
Comments: 9 pages, AA accepted

Redistributing hot gas around galaxies: do cool clouds signal a solution to the overcooling problem?
Tobias Kaufmann, James S. Bullock, Ariyeh H. Maller, Taotao Fang and James Wadsley, 2009, MNRAS, 396, 191
Full Text: HTML, PDF (Size: 20923K)

Acceleration of galactic supershells by Lyα radiation
Mark Dijkstra and Abraham Loeb, 2009, MNRAS, 396, 377
Full Text: HTML, PDF (Size: 608K)

The Star Formation Rate in the Reionization Era as Indicated by Gamma-ray Bursts
Matthew D. Kistler, Hasan Yuksel, John F. Beacom, Andrew M. Hopkins, J. Stuart B. Wyithe, arXiv:0906.0590 [ps, pdf, other]
Comments: 4 pages, 4 figures

The Evolution of Gas Clouds Falling in the Magnetized Galactic Halo: High Velocity Clouds (HVCs) Originated in the Galactic Fountain
Kyujin Kwak, Robin L. Shelton, Elizabeth A. Raley, arXiv:0906.0613 [ps, pdf, other]
Comments: 46 pages, 16 figures, 3 tables. Accepted for publication in ApJ

AGN and Black Holes

Self-Regulation of AGN in Galaxy Clusters
M. Brueggen, E. Scannapieco, arXiv:0905.4726 [ps, pdf, other]
Comments: accepted by MNRAS

Towards a Complete Census of AGNs in Nearby Galaxies: A Large Population of Optically Unidentified AGNs
Andy Goulding, Dave Alexander, arXiv:0906.0772 [ps, pdf, other]
Comments: 33 pages, 11 figures, accepted for publication in MNRAS

X-ray Astronomy

Non-Maxwellian electron distributions in clusters of galaxies
J.S. Kaastra, A.M. Bykov, N. Werner, arXiv:0905.4802 [ps, pdf, other]
Comments: 6 pages, 4 figures, accepted for publication in Astronomy and Astrophysics, main journal

The MAXI Mission on the ISS: Science and Instruments for Monitoring All Sky X-Ray Images
Masaru Matsuoka, et al, arXiv:0906.0631 [ps, pdf, other]
Comments: 12 pages, 11 figures, accepted for publication in Publications of the Astronomical Society of Japan


Resolving mixing in Smoothed Particle Hydrodynamics
J. I. Read, T. Hayfield, O. Agertz, arXiv:0906.0774 [ps, pdf, other]
Comments: Submitted to MNRAS. An OSPH patch for GADGET-2, some movies, our full multiphase test suite, and a high resolution version of the paper are all available for download from the Astro-Code wiki: this http URL

The Perils of Clumpfind: The Mass Spectrum of Sub-structures in Molecular Clouds
Jaime E. Pineda, Erik W. Rosolowsky, Alyssa A. Goodman, arXiv:0906.0331 [ps, pdf, other]
Comments: 5 pages, 3 figures. Accepted for publication in ApJ Letters

Full abstract: "We study the mass spectrum of sub-structures in the Perseus Molecular Cloud Complex traced by 13CO (1-0), finding that $dN/dM\propto M^{-2.4}$ for the standard Clumpfind parameters. This result does not agree with the classical $dN/dM\propto M^{-1.6}$. To understand this discrepancy we study the robustness of the mass spectrum derived using the Clumpfind algorithm. Both 2D and 3D Clumpfind versions are tested, using 850 $\mu$m dust emission and 13CO spectral-line observations of Perseus, respectively. The effect of varying threshold is not important, but varying stepsize produces a different effect for 2D and 3D cases. In the 2D case, where emission is relatively isolated (associated with only the densest peaks in the cloud), the mass spectrum variability is negligible compared to the mass function fit uncertainties. In the 3D case, however, where the 13CO emission traces the bulk of the molecular cloud, the number of clumps and the derived mass spectrum are highly correlated with the stepsize used. The distinction between "2D" and "3D" here is more importantly also a distinction between "sparse" and "crowded" emission. In any "crowded" case, Clumpfind should not be used blindly to derive mass functions. Clumpfind's output in the "crowded" case can still offer a statistical description of emission useful in inter-comparisons, but the clump-list should not be treated as a robust region decomposition suitable to generate a physically-meaningful mass function. We conclude that the 13CO mass spectrum depends on the observations resolution, due to the hierarchical structure of MC. "

Statistical techniques in cosmology
Alan Heavens, arXiv:0906.0664 [pdf, other]
Comments: Lectures given at the 'Francesco Lucchin' summer school, Bertinoro, Italy, May 2009, Director G. Zamorani

Public Perception of Astronomers: Revered, Reviled and Ridiculed
Michael J. West, arXiv:0905.3956 [pdf, other]
Comments: Invited review to appear in The Role of Astronomy in Society and Culture: Proceedings of IAU Symposium No. 260, 2009. D. Valls-Gabaud and A. Boksenberg, eds; typos corrected in revised version

V. Interesting.

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