B. T. Draine, G. Aniano, Oliver Krause, Brent Groves, Karin Sandstrom, Robert Braun, Adam Leroy, Ulrich Klaas, Hendrik Linz, Hans-Walter Rix, Eva Schinnerer, An… 展开作者
B. T. Draine, G. Aniano, Oliver Krause, Brent Groves, Karin Sandstrom, Robert Braun, Adam Leroy, Ulrich Klaas, Hendrik Linz, Hans-Walter Rix, Eva Schinnerer, Anika Schmiedeke, Fabian Walter
备注：
Final version (corrected and revised), to appear in ApJ, 780, 172 (2014 Jan 10)
Spitzer Space Telescope and Herschel Space Observatory imaging of M31 is used, with a physical dust model, to construct maps of dust surface density, dust-to-gas ratio, starlight heating intensity, and PAH abundance, out to R=25kpc. The global dust mass is M_d=5.4x10^7Msol, the global dust/H mass ratio is M_d/M_H=0.0081, and the global PAH abundance is <q_PAH>=0.039. The dust surface density has an inner ring at R=5.6kpc, a maximum at R=11.2kpc, and an outer ring at R=15.1kpc. The dust/gas ratio varies from M_d/M_H=0.026 at the center to ~0.0027 at R=25kpc. From the dust/gas ratio, we estimate the ISM metallicity to vary by a factor ~10, from Z/Zsol=3 at R=0 to ~0.3 at R=25kpc. The dust heating rate parameter <U> peaks at the center, with <U> approx 35, declining to <U> approx 0.25 at R=20kpc. Within the central kpc, the starlight heating intensity inferred from the dust modeling is close to what is estimated from the stars in the bulge. The PAH abundance reaches a peak q_PAH=0.045 at R=11.2kpc. When allowance is made for the different spectrum of the bulge stars, q_PAH for the dust in the central kpc is similar to the overall value of q_PAH in the disk. The silicate-graphite-PAH dust model used here is generally able to reproduce the observed dust spectral energy distribution across M31, but overpredicts 500um emission at R=2-6kpc, suggesting that at R=2-6kpc, the dust opacity varies more steeply with frequency (with beta approx 2.3 between 200 and 600um) than in the model
The abundance and emission of PAHs from the local to early Universe
University of Florida（佛罗里达大学）；University of Copenhagen（哥本哈根大学）；Technical University of Denmark（丹麦技术大学）；University of Virginia（弗吉尼亚大学）；INAF, Osservatorio Astronomico di Trieste（意大利国家天体物理研究所的的里雅斯特天文台）；Institute for Fundamental Physics of the Universe（宇宙基础物理研究所）；Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）；University of Texas at Austin（德克萨斯大学奥斯汀分校）；University of Massachusetts, Amherst（马萨诸塞大学阿默斯特分校）；European Southern Observatory（欧洲南方天文台）；Centro de Astrobiologia (CAB), CSIC-INTA（西班牙国家研究委员会-国家航空航天技术研究所天体生物学中心）
Reconstructing the stellar mass distributions of galaxies using S4G IRAC 3.6 and 4.5 micron images: I. Correcting for contamination by PAH, hot dust, and intermediate age stars
