Friday, January 15, 2010

Interesting Astrophysics: 01 Jan to 15 Jan, 2010

The first two weeks of 2010 have produced a number of interesting papers and preprints.

Of particular interest to me are starburst/galactic wind related papers (Moiseev et al; Westmoquette et al; Beaulieu et al), hot gas in galaxy halos (Nipoti; Marinacci et al), and AGN outflows (Morganti et al; Storchi-Bergmann).

Finally, the International X-ray Observatory team's response to the NAS's Astro2010 Decadal Survey's Request For Information (Bookbinder et al) is well worth a read, particularly if you're not familiar with X-ray astronomy's unique capabilities.

Galaxies and Starbursts

Ionized gas outflow in the isolated S0 galaxy NGC 4460
Authors: Alexei Moiseev, Igor Karachentsev, Serafim Kaisin, arXiv:1001.0234 [ps, pdf, other]
Comments: 11 pages, 7 figures; accepted by MNRAS

From their abstract: "We use integral-field and long-slit spectroscopy to study the bright extended nebulosity discovered in the isolated lenticular galaxy NGC 4460 during a recent H-alpha survey of nearby galaxies. An analysis of archival SDSS, GALEX, and HST images indicates that current star formation is entirely concentrated in the central kiloparsec of the galaxy disc. The observed ionized gas parameters (morphology, kinematics and ionization state) can be explained by a gas outflow above the plane of the galaxy caused by a star formation in the circumnuclear region. Galactic wind parameters in NGC 4460: outflow velocity, total kinetic energy - are several times smaller comparing with the known galactic wind in NGC 253, which is explained substantially lower total star formation rate."

Ionized gas in the starburst core and halo of NGC 1140
Authors: M. S. Westmoquette, J. S. Gallagher III, L. de Poitiers, arXiv:1001.0698 [ps, pdf, other]
Comments: 13 pages, 9 figures (6 colour). Accepted for publication in MNRAS

Supernova Remnants and the Interstellar Medium of M83: Imaging & Photometry with WFC3 on HST
Authors: Michael A. Dopita, et al, arXiv:1001.0815 [pdf, other]
Comments: Accepted for publication in Astrophysical Journal. 10 figures, 41 pp

Are galactic coronae thermally unstable?
Authors: Carlo Nipoti, arXiv:1001.1246 [ps, pdf, other]
Comments: 4 pages, to appear in "Hunting for the Dark: The Hidden Side of Galaxy Formation", Malta, 19-23 Oct. 2009, eds. V.P. Debattista & C.C. Popescu, AIP Conf. Ser

A lower limit of 50 microgauss for the magnetic field near the Galactic Centre
Authors: Roland M. Crocker, David Jones, Fulvio Melia, J├╝rgen Ott, Raymond J. Protheroe
Comments: Published in Nature. 17 page main article; 4 figures, arXiv:1001.1275 [pdf, other]
Journal-ref: Nature 468, 7277, p65, 2010

Unveiling the Sigma-Discrepancy in IR-Luminous Mergers I: Dust & Dynamics

Authors: Barry Rothberg, Jacqueline Fischer, arXiv:1001.1309 [ps, pdf, other]
Comments: Accepted for publication in The Astrophysical Journal. 82 pages, 19 Figures, 2 Appendice

Variations in Integrated Galactic Initial Mass Functions due to Sampling Method and Cluster Mass Function
Authors: M. R. Haas, P. Anders, arXiv:1001.2009 [ps, pdf, other]
Comments: Resubmitted to A&A, 14 pages, 9 Figures

From their abstract: "If the integrated galactic initial mass function originates from stars formed in clusters, the IGIMF could be steeper than the IMF. We investigate how well constrained this steepening is and how it depends on the choice of sampling method and CMF. We compare analytic sampling to several implementations of random sampling of the IMF, and different CMFs. ... As we still do not understand the details of star formation, one sampling method cannot be favoured over another. Also, the CMF at very low cluster masses is not well constrained observationally. These uncertainties need to be taken into account when using an IGIMF, with severe implications for galaxy evolution models and interpretations of galaxy observations."

The Recent Star Formation History of NGC 5102
Authors: Sylvie F. Beaulieu, Kenneth C. Freeman, Sebastian L. Hidalgo, Colin A. Norman, Peter J. Quinn, arXiv:1001.2236 [ps, pdf, other]
Comments: 36 pages, 16 figures, accepted in AJ

The mode of gas accretion onto star-forming galaxies
Authors: F. Marinacci, J. Binney, F. Fraternali, C. Nipoti, L. Ciotti, P. Londrillo, arXiv:1001.2446 [ps, pdf, other]
Comments: 12 pages, 8 figures, 1 table. Accepted for publication in MNRAS

Their abstract: "It is argued that galaxies like ours sustain their star formation by transferring gas from an extensive corona to the star-forming disc. The transfer is effected by the galactic fountain -- cool clouds that are shot up from the plane to kiloparsec heights above the plane. The Kelvin-Helmholtz instability strips gas from these clouds. If the pressure and the the metallicity of the corona are high enough, the stripped gas causes a similar mass of coronal gas to condense in the cloud's wake. Hydrodynamical simulations of cloud-corona interaction are presented. These confirm the existence of a critical ablation rate above which the corona is condensed, and imply that for the likely parameters of the Galactic corona this rate lies near the actual ablation rate of clouds. In external galaxies trails of HI behind individual clouds will not be detectable, although the integrated emission from all such trails should be significant. Parts of the trails of the clouds that make up the Galaxy's fountain should be observable and may account for features in targeted 21-cm observations of individual high-velocity clouds and surveys of Galactic HI emission. Taken in conjunction with the known decline in the availability of cold infall with increasing cosmic time and halo mass, the proposed mechanism offers a promising explanation of the division of galaxies between the blue cloud to the red sequence in the colour-luminosity plane. "

Interesting. I must take a closer look at the necessary conditions for the mass-loading of the local corona due to stripped gas from the clouds to cause coronal condensation.

Black Holes, AGN and other compact accreting objects

In-depth studies of the NGC 253 ULXs with XMM-Newton: remarkable variability in ULX1, and evidence for extended coronae
Authors: R. Barnard, arXiv:1001.0870 [ps, pdf, other]
Comments: Accepted for publication in MNRAS. 7 pages, 5 figures

Cold and Warm Gas Outflows in Radio AGN
Authors: Raffaella Morganti, Joanna Holt, Clive Tadhunter, Tom Oosterloo, arXiv:1001.2389 [ps, pdf, other]
Comments: Invited talk, to appear in the Proceedings of the IAU Symposium 267, "Co-Evolution of Central Black Holes and Galaxies", B.M. Peterson, R.S. Somerville, T. Storchi-Bergmann, eds., in press

From their abstract: "Clear evidence for AGN-induced outflows have been found for the majority of these young radio sources. The outflows are detected both in (warm) ionized as well in (cold) atomic neutral gas and they are likely to be driven (at least in most of the cases) by the interaction between the expanding jet and the medium. The mass outflow rates of the cold gas (HI) appear to be systematically higher than those of the ionized gas. The former reach up to ~50 Msun/yr, and are in the same range as "mild" starburst-driven superwinds in ULIRGs, whilst the latter are currently estimated to be a few solar masses per year. However, the kinetic powers associated with these gaseous outflow are a relatively small fraction (a few x 10^-4) of the Eddington luminosity of the galaxy. Thus, they do not appear to match the requirements of the galaxy evolution feedback models."

Inflows and outflows in nearby active galactic nuclei from integral field spectroscopy
Authors: Thaisa Storchi-Bergmann, arXiv:1001.2480 [ps, pdf, other]
Comments: 8 pages, 4 figures, to be published in the Proceedings of the IAU Symposium no. 267, eds. B.M. Peterson, R.S. Somerville and T. Storchi-Bergmann, 2010

Stars, Supernovae and Planets

Supernova 2007bi as a pair-instability explosion
Authors: A. Gal-Yam, et al, arXiv:1001.1156 [ps, pdf, other]
Comments: Accepted version of the paper appearing in Nature, 462, 624 (2009), including all supplementary information
Journal-ref: Nature 462 624 (2009)

Second generation planets
Authors: Hagai B. Perets, arXiv:1001.0581 [ps, pdf, other]
Comments: 8 pages. Comments are most welcome

Self-consistent Simulations of Alfven Wave Driven Winds from the Sun and Stars
Authors: Takeru K. Suzuki, arXiv:1001.2400 [ps, pdf, other]
Comments: 26 pages, 12 figures, submitted to special issue (BUKS 2009) of Space Science Review

H II regions: Witnesses to massive star formation
Authors: Thomas Peters, Robi Banerjee, Ralf S. Klessen, Mordecai-Mark Mac Low, Roberto Galvan-Madrid, Eric Keto, arXiv:1001.2470 [pdf, other]
Comments: ApJ in press
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Galaxy Astrophysics (astro-ph.GA)

Nice simulations.


Pointing the SOFIA Telescope
Authors: Michael A. K. Gross, John J. Rasmussen, Elizabeth M. Moore, arXiv:1001.0197 [ps, pdf, other]
Comments: 4 pages, 3 figures. To appear in Proc. ADASS XIX (Sapporo, Japan, 2009)

The International X-ray Observatory - RFI#1
Authors: Jay Bookbinder (on behalf of the IXO Study Coordination Group, Science Definition Team, Instrument Working Group, and Telescope Working Group), arXiv:1001.2329 [pdf]
Comments: 19 pages, submitted in response to Astro2010 Decadal Program Prioritization Panel First Request for Information

Contains a nice summary of the unique science capabilities of IXO, along with a variety of interesting hardware and other technical information. Anticipated lauch date 2021. Good luck, IXO team!

Post a Comment