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RISS 인기검색어
- 검색키워드
- 저자 : Tremonti, C. (검색결과 3 건)
- 무료
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- 유료
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Violent Quenching: Molecular Gas Blown to 1000 km s<sup>−1</sup> during a Major Merger
Geach, J. E.,Tremonti, C.,Diamond-Stanic, A. M.,Sell, P. H.,Kepley, A. A.,Coil, A. L.,Rudnick, G.,Hickox, R. C.,Moustakas, J.,Yang, Yujin American Astronomical Society 2018 ASTROPHYSICAL JOURNAL LETTERS - Vol.864 No.1
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Clocking the Evolution of Post-starburst Galaxies: Methods and First Results
French, K. Decker,Yang, Yujin,Zabludoff, Ann I.,Tremonti, Christy A. American Astronomical Society 2018 The Astrophysical journal Vol.862 No.1
<P>Detailed modeling of the recent star formation histories (SFHs) of post-starburst (or 'E+A') galaxies is impeded by the degeneracy between the time elapsed since the starburst ended (post-burst age), the fraction of stellar mass produced in the burst (burst strength), and the burst duration. To resolve this issue, we combine GALEX ultraviolet photometry, SDSS photometry and spectra, and new stellar population synthesis models to fit the SFHs of 532 post-starburst galaxies. In addition to an old stellar population and a recent starburst, 48% of the galaxies are best fit with a second recent burst. Lower stellar mass galaxies (log M-*/M-circle dot<10.5) are more likely to experience two recent bursts, and the fraction of their young stellar mass is more strongly anticorrelated with their total stellar mass. Applying our methodology to other, younger post-starburst samples, we identify likely progenitors to our sample and examine the evolutionary trends of molecular gas and dust content with post-burst age. We discover a significant (4 sigma) decline, with a 117-230 Myr characteristic depletion time, in the molecular gas to stellar mass fraction with the post-burst age. The implied rapid gas depletion rate of 2-150 M(circle dot)yr(-1) cannot be due to current star formation, given the upper limits on the current star formation rates in these post-starbursts. Nor are stellar winds or supernova feedback likely to explain this decline. Instead, the decline points to the expulsion or destruction of molecular gas in outflows, a possible smoking gun for active galactic nucleus feedback.</P>
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After the Fall: The Dust and Gas in E+A Post-starburst Galaxies
Smercina, A.,Smith, J. D. T.,Dale, D. A.,French, K. D.,Croxall, K. V.,Zhukovska, S.,Togi, A.,Bell, E. F.,Crocker, A. F.,Draine, B. T.,Jarrett, T. H.,Tremonti, C.,Yang, Yujin,Zabludoff, A. I. American Astronomical Society 2018 The Astrophysical journal Vol.855 No.1
<P>The traditional picture of post-starburst galaxies as dust-and gas-poor merger remnants, rapidly transitioning to quiescence, has been recently challenged. Unexpected detections of a significant interstellar medium (ISM) in many post-starburst galaxies raise important questions. Are they truly quiescent, and if so, what mechanisms inhibit further star formation? What processes dominate their ISM energetics? We present an infrared spectroscopic and photometric survey of 33 E+A post-starbursts selected by the Sloan Digital Sky Survey, aimed at resolving these questions. We find compact, warm dust reservoirs with high PAH abundances and total gas and dust masses significantly higher than expected from stellar recycling alone. Both polycyclic aromatic hydrocarbon (PAH)/total infrared (TIR) and dust-to-burst stellar mass ratios are seen to decrease with post-burst age, indicative of the accumulating effects of dust destruction and an incipient transition to hot, early-type ISM properties. Their infrared spectral properties are unique, with dominant PAH emission, very weak nebular lines, unusually strong H-2. rotational emission, and deep [C II] deficits. There is substantial scatter among star formation rate (SFR) indicators, and both PAH and TIR luminosities provide overestimates. Even as potential upper limits, all tracers show that the SFR has typically experienced a decline of more than two orders of magnitude since the starburst and that the SFR is considerably lower than expected given both their stellar masses and molecular gas densities. These results paint a coherent picture of systems in which star formation was, indeed, rapidly truncated, but in which the ISM was not completely expelled, and is instead supported against collapse by latent or continued injection of turbulent or mechanical heating. The resulting aging burst populations provide a 'high-soft' radiation field that seemingly dominates the E+A galaxies' unusual ISM energetics.</P>
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