Friday, December 18, 2009

Interesting Astrophysics: Dec 07 to 18

Not a white christmas but a windy one: Razoumov, Westmoquette et al, Rubin et al, Vanzella et al, Crenshaw et al, and Kobulnicky et al are all wind-related papers or preprints (and mainly on galactic winds). Another paper of particular note is Welsh et al's amazing 3-D mapping of the local neutral ISM (within 300 pc) using NaI and CaII absorption line spectroscopy toward 1857 nearby early-type stars.

Galaxies and Starbursts

Damped Lyα Absorber Kinematics and Outflows from Starburst Galaxies
Razoumov, Alexei O., 2009, The Astrophysical Journal, Volume 707, Issue 1, pp. 738-749.
PDF (1.84 MB) | HTML

VLT/FLAMES-ARGUS observations of stellar wind-ISM cloud interactions in NGC 6357
Westmoquette, M. S.; Slavin, J. D.; Smith, L. J.; Gallagher, J. S., III, 2009, MNRAS, in press
Full Text: HTML, PDF (Size: 2563K)

PAH processing in a hot gas
E. R. Micelotta, A. P. Jones, A. G. G. M. Tielens, arXiv:0912.1595 [ps, pdf, other]
Comments: 16 pages, 11 figures, accepted for publication in Astronomy and Astrophysics

From their abstract: "The PAH lifetime in a tenuous hot gas (n_H ~ 0.01 cm^-3, T ~ 10^7 K), typical of the coronal gas in galactic outflows, is found to be about thousand years, orders of magnitude shorter than the typical lifetime of such objects. Conclusions: In a hot gas, PAHs are principally destroyed by electron collisions and not by the absorption of X-ray photons from the hot gas. The resulting erosion of PAHs occurs via C_2 loss from the periphery of the molecule, thus preserving the aromatic structure. The observation of PAH emission from a million degree, or more, gas is only possible if the emitting PAHs are ablated from dense, entrained clumps that have not yet been exposed to the full effect of the hot gas."

The Persistence of Cool Galactic Winds in High Stellar Mass Galaxies Between z~1.4 and ~1
Kate H. R. Rubin, Benjamin J. Weiner, David C. Koo, Crystal L. Martin, J. Xavier Prochaska, Alison L. Coil, Jeffrey A. Newman, arXiv:0912.2343 [ps, pdf, other]
Comments: Submitted to ApJ. 25 pages, 19 figures, Figure 2 reduced in resolution. Uses emulateapj format

From their abstract: "We present an analysis of the MgII 2796, 2803 and FeII 2586, 2600 absorption line profiles in coadded spectra of 468 galaxies at 0.7 < z < 1.5. ... The outflows
have hydrogen column densities N(H) > 10^19.3 cm^-2, and extend to velocities
of ~500 km/s. While galaxies with SFR > 10 Msun/yr host strong outflows in both
this and the W09 sample, we do not detect outflows in lower-SFR (i.e., log
M_*/Msun < 10.5) galaxies at lower redshifts. Using a simple galaxy evolution
model which assumes exponentially declining SFRs, we infer that strong outflows
persist in galaxies with log M_*/Msun > 10.5 as they age between z=1.4 and z~1,
presumably because of their high absolute SFRs. Finally, using high resolution
HST/ACS imaging in tandem with our spectral analysis, we find evidence for a
weak trend (at 1 sigma significance) of increasing outflow absorption strength
with increasing galaxy SFR surface density."

The unusual NIV]-emitter galaxy GDS J033218.92-275302.7: star formation or AGN-driven winds from a massive galaxy at z=5.56
E. Vanzella, A. Grazian, M. Hayes, L. Pentericci, D. Schaerer, M. Dickinson, S. Cristiani, M. Giavalisco, A. Verhamme, M. Nonino, P. Rosati, arXiv:0912.3007 [ps, pdf, other]
Comments: 13 pages, 9 figures. Accepted for publication in Astronomy and Astrophysics

The central energy source of 70micron-selected galaxies: Starburst or AGN?
M. Symeonidis, D. Rosario, A. Georgakakis, J. Harker, E. S. Laird, M. J. Page
Comments: 20 pages, 14 figures, accepted for publication in MNRAS

It is starbursts.

Model analysis of the very high energy detections of the starburst galaxies M82 and NGC 253
E. de Cea del Pozo, D. F. Torres, A. Y. Rodriguez, O. Reimer, arXiv:0912.3497 [ps, pdf, other]
Comments: 6 pages, 3 figures, 2 tables, 2009 Fermi Symposium, eConf Proceedings C091122

Black Holes and AGN

The Geometry of Mass Outflows and Fueling Flows in the Seyfert 2 Galaxy Mrk 3
D.M. Crenshaw, S.B. Kraemer, H.R. Schmitt, Y.L. Jaffe, R.P. Deo, N.R. Collins, T.C. Fischer, arXiv:0912.2420 [ps, pdf, other]
Comments: 22 page, 7 figures, accepted for publication in the Astronomical Journal

Their abstract: We present a study of the resolved emission-line regions and an inner dust/gas disk in the Seyfert 2 galaxy Mrk 3, based on Hubble Space Telescope observations. We show that the extended narrow-line region (ENLR), spanning ~4 kpc, is defined by the intersection of the ionizing bicone of radiation from the AGN and the inner disk, which is not coplanar with the large-scale stellar disk. This intersection leads to different position and opening angles of the ENLR compared to the narrow-line region (NLR). A number of emission-line arcs in the ENLR appear to be continuations of dust lanes in the disk, supporting this geometry. The NLR, which consists of outflowing emission-line knots spanning the central ~650 pc, is in the shape of a backwards S. This shape may arise from rotation of the gas, or it may trace the original fueling flow close to the nucleus that was ionized after the AGN turned on."

Stars, Supernovae and Planets

OB Stars & Stellar Bowshocks in Cygnus-X: A Novel Laboratory Estimating Stellar Mass Loss Rates
Henry A. Kobulnicky, Ian J. Gilbert, Daniel C. Kiminki, arXiv:0912.1314 [ps, pdf, other]
Comments: 49 pages, 19 figures; Accepted for publication in ApJ; full-resolution color figure version available at this http URL; comments invited

CoRoT-7 b: Super-Earth or Super-Io?
Rory Barnes, Sean N. Raymond, Richard Greenberg, Brian Jackson, Nathan A. Kaib, arXiv:0912.1337 [ps, pdf, other]
Comments: 13 pages, 3 figures, accepted to ApJ Letters

The simultaneous formation of massive stars and stellar clusters
Rowan J. Smith, Steven Longmore and Ian Bonnell, 2009, MNRAS, 400, 1775
Full Text: HTML, PDF (Size: 20619K)

Updated stellar yields from Asymptotic Giant Branch models
Amanda I. Karakas, arXiv:0912.2142 [ps, pdf, other]
Comments: Accepted for publication in MNRAS; 15 pages

New 3-D gas density maps of NaI and CaII interstellar absorption within 300pc
Barry Y. Welsh, Rosine Lallement, Jean-Luc Vergely, Severine Raimond, arXiv:0912.3040 [ps, pdf, other]
Comments: A&amp;A accepted

The NaI and CaII distributions are quite different. A very impressive piece of work.

Numerical Methods and Theoretical Astrophysics

Astrophysical turbulence
Axel Brandenburg, Aake Nordlund, arXiv:0912.1340 [ps, pdf, other]
Comments: 80 pages, 24 figures, submitted to Reports on Progress in Physics. For higher figure quality and more frequent revisions see this http URL

Detailed Decomposition of Galaxy Images. II. Beyond Axisymmetric Models
Chien Y. Peng, Luis C. Ho, Chris D. Impey, Hans-Walter Rix, arXiv:0912.0731 [ps, pdf, other]
Comments: 41 pages, 22 figures, AJ submitted. Comments welcomed. Full resolution version of this paper is available at: this http URL

Dynamical Models for the Formation of Elephant Trunks in H II Regions
Jonathan Mackey, Andrew J. Lim, arXiv:0912.1499 [ps, pdf, other]
Comments: 19 pages, 11 figures, accepted for publication in MNRAS. Version with high resolution figures available at this http URL

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