## Friday, February 19, 2010

### Interesting Astrophysics: Feb 01 to Feb 19, 2010

I have no time to provide commentary, so without further interruption here are the papers and preprints that I consider interesting that have appeared over the period Feb 01-19, 2010.

Galaxies and Starbursts

The AGN properties of the starburst galaxy NGC 7582
T.V. Ricci, J.E. Steiner, R.B. Menezes, A. Garcia-Rissmann, R. Cid Fernandes,
Comments: 1 page, 2 figures, to be published in the Proceedings of the IAU Symposium no. 267

The stellar populations of the AGN/Starburst galaxy NGC7582
T.V. Ricci, J.E. Steiner, R.B. Menezes, A. Garcia-Rissmann, R. Cid Fernandes,
Comments: 2 pages, 2 figures, to be published in the Proceedings of the IAU Symposium no. 262

Their abstract: "NGC 7582 is defined as a Starburst/AGN galaxy, since its optical and X-Ray spectra reveal both characteristics. In this work, we show the results of a stellar population modeling in a datacube taken with the Gemini South telescope. We found that $\sim$ 90% of the light in the field of view is emitted by stars that are less than 1 billion years old. A strong burst occurred about $\sim$ 6 million years ago and has nearly solar metallicity. We also found a Wolf-Rayet cluster."

Star Formation in the Outer Filaments of NGC 1275
R.E.A. Canning, A.C. Fabian, R.M. Johnstone, J.S. Sanders, C.J. Conselice, C.S. Crawford, J.S. Gallagher III, E. Zweibel,
Comments: Accepted for publication in MNRAS, 14 pages, 14 figures, 3 tables

A panoramic view of the Milky Way analogue NGC 891
M. Mouhcine, R. Ibata, M. Rejkuba,
Comments: 2 figures, Apj Letter, in press

A panoramic view of M81: New stellar systems in the debris field
M. Mouhcine, R. Ibata,

Evidence of Early Enrichment of the Galactic Disk by Large-Scale Winds
T. Tsujimoto, J. Bland-Hawthorn, K.C. Freeman,
Comments: 9 pages including 5 figures, accepted for publication in PASJ

Starburst evolution: free-free absorption in the radio spectra of luminous IRAS galaxies
M. S. Clemens, A. Scaife, O. Vega, A. Bressan,
Comments: 13 pages, 5 figures, accepted by MNRAS

Metal-line emission from the warm-hot intergalactic medium: II. Ultraviolet
Serena Bertone, Joop Schaye, C.M. Booth, Claudio Dalla Vecchia, Tom Theuns, Robert P.C. Wiersma,
Comments: 21 pages, 22 figures. Submitted to MNRAS

Their abstract: "Approximately half the baryons in the local Universe are thought to reside in the warm-hot intergalactic medium (WHIM). Emission lines from metals in the UV band are excellent tracers of the cooler fraction of this gas. We present predictions for the surface brightness of a sample of UV lines that could potentially be observed by the next generation of UV telescopes at z<1. We use a subset of simulations from the OWLS project to create emission maps and to investigate the effect of varying the physical prescriptions for star formation, supernova and AGN feedback, chemodynamics and radiative cooling. Most models produce results in agreement within a factor of a few, indicating that the predictions are robust. Of the lines we consider, C III is the strongest line, but it typically traces gas colder than 10^5 K. The same is true for Si IV. The second strongest line, C IV, traces circum-galactic gas with T~10^5 K. O VI and Ne VIII probe the warmer (T~10^5.5 K and T~10^6 K, respectively) and more diffuse gas that may be a better tracer of the large scale structure. N V emission is intermediate between C IV and O VI. The intensity of all emission lines increases strongly with gas density and metallicity, and for the bright emission it is tightly correlated with the temperature for which the line emissivity is highest. In particular, the C III, C IV, Si IV and O VI emission that is sufficiently bright to be potentially detectable in the near future (>10^3 photon/s/cm^2/sr), comes from relatively dense (rho>10^2 rho_mean) and metal rich (Z>0.1 Z_sun) gas. As such, emission lines are highly biased tracers of the missing baryons and are not an optimal tool to close the baryon budget. However, they do provide a powerful means to detect the gas cooling onto or flowing out of galaxies and groups. (Abridged)"

Black Holes and AGN

Timing the starburst-AGN connection
Vivienne Wild, Timothy Heckman, Stephane Charlot,
Comments: 16 pages, 12 figures, accepted for publication in MNRAS

Interstellar Medium

Metal-Ion Absorption in Conductively Evaporating Clouds
Orly Gnat, Amiel Sternberg, Christopher F. McKee,

ITERA: IDL Tool for Emission-line Ratio Analysis
Brent Groves, Mark Allen,

Stars, Supernove and Planets

The Birth Environment of the Solar System
Comments: 58 pages including 7 figures, to appear in Annual Reviews of Astronomy and Astrophysics (2010, Vol. 48)

Absract in full: "This paper reviews our current understanding of the possible birth environments of our Solar System. Since most stars form within groups and clusters, the question becomes one of determining the nature of the birth aggregate of the Sun. This discussion starts by reviewing Solar System properties that provide constraints on our environmental history. We then outline the range of star-forming environments that are available in the Galaxy, and discuss how they affect star and planet formation. The nature of the solar birth cluster is constrained by many physical considerations, including radiation fields provided by the background environment, dynamical scattering interactions, and by the necessity of producing the short-lived radioactive nuclear species inferred from meteoritic measurements. Working scenarios for the solar birth aggregate can be constructed, as discussed herein, although significant uncertainties remain."

A scenario of planet erosion by coronal radiation
J. Sanz-Forcada, I. Ribas, G. Micela, A. M. T. Pollock, D. Garcia-Alvarez, E. Solano, C. Eiroa,
Comments: Accepted by A&A Letters (8 Feb. 2010). 4 pages, 3 figures, 1 online table (included)

On the Disruption of Star Clusters in a Hierarchical Interstellar Medium
Bruce G. Elmegreen, Deidre A. Hunter,
Comments: ApJ vol. 712, March 20, 2010, 33 pages 15 figures

Do Wolf-Rayet stars have similar locations in hosts as type Ib/c supernovae and long gamma-ray bursts?
G. Leloudas, J. Sollerman, A. J. Levan, J. P. U. Fynbo, D. Malesani, J. R. Maund,
Comments: Under review in A&amp;A. The present version includes suggestions from the referee