Friday, December 04, 2009

Interesting Astrophysics: Nov 23 to Dec 04, 2009


In honor of the Thanksgiving Day Holiday here in the US the preprint server has produced a veritable feast of interesting papers over the last two weeks.

Of particular note are the following.

Radio spectra of everyone's favorite starbursts galaxies: M82, NGC 253 and Arp 220 (Williams & Bower). Cosmological N-body/SPH simulations affirming the importance of galactic winds, only not quite in the normal way (Oppenheimer et al).

An apparently physically large (6+ kpc) and powerful wind in the AGN SDSS J0318-0600 (Dunn et al), but note that... Krug et al find that AGN probably do not play a significant role in driving the outflows from most Seyfert galaxies, except possibly the high velocity outflows in some Seyfert 1s. Camus et al and Falceta-Goncalves et al have interesting, but very different, simulations of filamentary structures in the Crab Nebula and NGC 1275 respectively (The HST press release image of NGC 1275 [Fabian et al] is shown above).

Sadakane et al find high velocity narrow Na I absorption lines in the spectrum of Nova V1280 Sco. Bowler et al find that massive planets appear significantly more common around A stars than G stars.


Galaxies and Starbursts

The properties of the stellar populations in ULIRGs II: the star formation histories and evolution
Javier Rodriguez-Zaurin, C.N. Tadhunter, R.M. Gonzalez-Delgado, arXiv:0911.4052 [ps, pdf, other]
Comments: Accepted for publication in MNRAS. The paper contains 16 pages, 6 figures and 7 tables

GALEX Ultraviolet Imaging of Dwarf Galaxies and Star Formation
Deidre A. Hunter, Bruce G. Elmegreen, Bonnie C. Ludka, arXiv:0911.4319 [ps, pdf, other]
Comments: 28 pages, 22 figures, 7 tables, to be published in Astronomical Journal

Forty Years of Research on Isolated Galaxies
J. W. Sulentic, arXiv:0911.5663 [ps, pdf, other]
Comments: 8 pages - to appear in the proceedings of 'Galaxies in Isolation: Exploring Nature vs. Nurture', held in Granada, Spain 12-15 May 2009. Editors: L. Verdes-Montenegro, A. del Olmo and J. Sulentic. PASP Conference Series

Evaluating the Calorimeter Model with Broadband, Continuous Spectra of Starburst Galaxies Observed with the Allen Telescope Array
Peter K. G. Williams, Geoffrey C. Bower, arXiv:0912.0014 [ps, pdf, other]
Comments: 44 pages, 15 figures, ApJ accepted

Their abstract: "Although the relationship between the far-infrared and cm-wave radio luminosities of normal galaxies is one of the most striking correlations in astronomy, a solid understanding of its physical basis is lacking. In one interpretation, the "calorimeter model," rapid synchrotron cooling of cosmic ray electrons is essential in reproducing the observed linear relationship. Observed radio spectra, however, are shallower than what is expected of cooled synchrotron emission. In Thompson et al. (2006), a simple parameterized model is presented to explain how relatively shallow observed spectra might arise even in the presence of rapid synchrotron cooling by accounting for ionization losses and other cooling mechanisms. During the commissioning of the 42-element Allen Telescope Array, we observed the starburst galaxies M82, NGC 253, and Arp 220 at frequencies ranging from 1 to 7 GHz, obtaining unprecedented broadband continuous radio spectra of these sources. We combine our observations with high-frequency data from the literature to separate the spectra into thermal and nonthermal components. The nonthermal components all steepen in the cm-wave regime and cannot be well-modeled as simple power laws. The model of Thompson et al. is consistent with our M82 results when plausible parameters are chosen, and our results in fact significantly shrink the space of allowed model parameters. The model is only marginally consistent with our NGC 253 data. Assuming the Thompson et al. model, a steep electron energy injection index of p = -2.5 is ruled out in M82 and NGC 253 to >99% confidence. We describe in detail the observing procedures, calibration methods, analysis, and consistency checks used for broadband spectral observations with the Allen Telescope Array."

Feedback and Recycled Wind Accretion: Assembling the z=0 Galaxy Mass Function
Benjamin D. Oppenheimer, Romeel Davé, Dušan Kereš, Mark Fardal, Neal Katz, Juna A. Kollmeier, David H. Weinberg, arXiv:0912.0519 [ps, pdf, other]
Comments: 15 pages, 6 figures, submitted to MNRAS


Black Holes & AGN

The Quasar Outflow Contribution to AGN Feedback: VLT Measurements of SDSS J0318-0600
Jay P. Dunn, Manuel A. Bautista, Nahum Arav, Maxwell Moe, Kirk T. Korista, Elisa Costantini, Chris Benn, Sara Ellison, Doug Edmonds, arXiv:0911.3896 [ps, pdf, other]
Comments: Accepted for publication in ApJ, 57 pages, 14 figures

From their abstract: "Due to the uncertainty in the location of the dust extinction, we arrive at two viable distances for the main ouflow component from the central source, 6 and 18 kpc, where we consider the 6 kpc location as somewhat more physically plausable. Assuming the canonical global covering of 20% for the outflow and a distance of 6 kpc, our analysis yields a mass flux of 120 M_sun yr^-1 and a kinetic luminosity that is ~0.1% of the bolometric luminosity of the object. Should the dust be part of the outflow, then these values are ~4x larger. The large mass flux and kinetic luminosity make this outflow a significant contributor to AGN feedback processes."

Neutral Gas Outflows and Inflows in Infrared-Faint Seyfert Galaxies
Hannah B. Krug, David S. N. Rupke, Sylvain Veilleux, arXiv:0911.3897 [ps, pdf, other]
Comments: 50 pages, 12 figures, accepted for publication in ApJ

From their abstract: "The present paper describes the results from a search for outflows in 35 infrared-faint Seyferts with 10^9.9 < L_IR/L_sun < 10^11, or, equivalently, star formation rates (SFR) of ~0.4 -- 9 solar masses per year, to attempt to isolate the source of the outflow. We find that the outflow detection rates for the infrared-faint Seyfert 1s (6%) and Seyfert 2s (18%) are lower than previously reported for infrared-luminous Seyfert 1s (50%) and Seyfert 2s (45%). The outflow kinematics of infrared-faint and infrared-bright Seyfert 2 galaxies resemble those of starburst galaxies, while the outflow velocities in Seyfert 1 galaxies are significantly larger. Taken together, these results suggest that the AGN does not play a significant role in driving the outflows in most infrared-faint and infrared-bright systems, except the high-velocity outflows seen in Seyfert 1 galaxies."

Radiation-Driven Outflows in Active Galactic Nuclei
Daniel Proga, Ryuichi Kurosawa, arXiv:0912.0565 [ps, pdf, other]
Comments: 9 pages, 5 figures, in Recent Directions In Astrophysical Quantitative Spectroscopy And Radiation Hydrodynamics: Proceedings of the International Conference in Honor of Dimitri Mihalas for His Lifetime Scientific Contributions on the Occasion of His 70th Birthday (AIP Conference Proceedings 1171)


Interstellar Medium / Hydrodynamics

Flows along cometary tails in the Helix planetary nebula NGC 7293
John Meaburn, Panos Boumis, arXiv:0911.4843 [ps, pdf, other]
Comments: 8 pages, 4 figures, accepted for publication in MNRAS

Properties of extra-planar HI clouds in the outer part of the Milky Way
L. Dedes, P.W.M Kalberla, arXiv:0911.4839 [ps, pdf, other]
Comments: 9 pages, 5 figures, 3 tables, Accepted for publication in A&A

Observations of 'wisps' in magnetohydrodynamic simulations of the Crab Nebula
N. F. Camus, S. S. Komissarov, N. Bucciantini and P. A. Hughes, 2009, MNRAS, 400, 1241
Full Text: HTML, PDF (Size: 7435K)

Turbulence and the formation of filaments, loops and shock fronts in NGC 1275 in the Perseus Galaxy Cluster
D. Falceta-Goncalves, E. M. de Gouveia Dal Pino, J. S. Gallagher, A. Lazarian, arXiv:0912.0545 [ps, pdf, other]
Comments: accepted by ApJ Letters


X-ray Astronomy

Methods for Estimating Fluxes and Absorptions of Faint X-ray Sources
Konstantin V. Getman, Eric D. Feigelson, Patrick S. Broos, Leisa K. Townsley, Gordon P. Garmire, arXiv:0912.0202 [ps, pdf, other]
Comments: Accepted for publication in The Astrophysical Journal. 39 pages, 15 figures


Stars, Supernovae and Planets

Introduction to nuclear astrophysics
Christian Iliadis, arXiv:0911.3965 [ps, pdf, other]
Comments: Proceedings of the 5th European Summer School on Experimental Nuclear Astrophysics, Santa Tecla, Italy, 2009, 20 pages, 4 figures, 1 table

Molecular Clouds as a Probe of Cosmic-Ray Acceleration in a Supernova Remnant
Yutaka Fujita, Yutaka Ohira, Shuta J. Tanaka, Fumio Takahara, arXiv:0911.4482 [ps, pdf, other]
Comments: Accepted for publication in ApJ Letters

Discovery of Multiple High-Velocity Narrow Circumstellar Na I D Lines in Nova V1280 Sco
Kozo Sadakane, Akito Tajitsu, Sahori Mizoguchi, Akira Arai, Hiroyuki Naito, arXiv:0911.5229 [ps, pdf, other]
Comments: Accepted for PASJ letter, 5 pages, 8 figures

Retired A Stars and Their Companions. III. Comparing the Mass-Period Distributions of Planets Around A-Type Stars and Sun-Like Stars
Brendan P. Bowler, John Asher Johnson, Geoffrey W. Marcy, Gregory W. Henry, Kathryn M. G. Peek, Debra A. Fischer, Kelsey I. Clubb, Michael C. Liu, Sabine Reffert, Christian Schwab, Thomas B. Lowe, arXiv:0912.0518 [ps, pdf, other]
Comments: Accepted by the Astrophysical Journal; 15 pages, 15 figures

From their abstract: "Thus, the properties of planets around A stars are markedly different than those around Sun-like stars, suggesting that only a small (~ 50%) increase in stellar mass has a large influence on the formation and orbital evolution of planets."


Other

A Multilingual on-line Dictionary of Astronomical Concepts
M. Heydari-Malayeri, arXiv:0911.4687 [pdf]

Comments: 3 pages, Interactive dictionary of Astronomy and Astrophysics, see: this http URL

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