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EVIDENCE FOR 1000 km s <sup>-1</sup> MOLECULAR OUTFLOWS IN THE LOCAL ULIRG POPULATION
Chung, Aeree,Yun, Min S.,Naraynan, Gopal,Heyer, Mark,Erickson, Neal R. IOP Publishing 2011 ASTROPHYSICAL JOURNAL LETTERS - Vol.732 No.1
<P>The feedback from galactic outflows is thought to play an important role in shaping the gas content, star formation history, and ultimately the stellar mass function of galaxies. Here we present evidence for massive molecular outflows associated with ultra-luminous infrared galaxies (ULIRGs) in the co-added Redshift Search Receiver (CO)-C-12 (1-0) spectrum. Our stacked spectrum of 27 ULIRGs at z = 0.043-0.11 (nu(rest) = 110-120 GHz) shows broad wings around the CO line with Delta V (FWZI) approximate to 2000 km s(-1). Its integrated line flux accounts for up to 25%+/- 5% of the total CO line luminosity. When interpreted as a massive molecular outflow wind, the associated mechanical energy can be explained by a concentrated starburst with star formation rate (SFR) >= 100 M-circle dot yr(-1), which agrees well with their SFR derived from the FIR luminosity. Using the high signal-to-noise stacked composite spectrum, we also probe (CO)-C-13 and (CN)-C-12 emission in the sample and discuss how the chemical abundance of molecular gas may vary depending on the physical conditions of the nuclear region.</P>
Characteristic Chemical Correlations in Nearby Star-forming Molecular Clouds
Hyeong-Sik Yun,Jeong-Eun Lee,Neal J. Evans II,Stella Offner,Mark H. Heyer,Yunhee Choi,Yong-Hee Lee,Giseon Baek,Minho Choi,Hyunwoo Kang,Ken’ichi Tatematsu,Seokho Lee,Yao-Lun Yang,Brandt Gaches,How-Huan 한국천문학회 2020 天文學會報 Vol.45 No.1
A 21 cm SPECTRAL AND CONTINUUM STUDY OF IC 443 USING THE VERY LARGE ARRAY AND THE ARECIBO TELESCOPE
Lee, Jae-Joon,Koo, Bon-Chul,Yun, Min S.,Stanimirović,, Snež,ana,Heiles, Carl,Heyer, Mark American Institute of Physics 2008 The Astronomical journal Vol.135 No.3
<P>We report 21 cm spectral-line and continuum observations of the Galactic supernova remnant IC 443 using the Very Large Array (VLA) and the Arecibo telescope. By combining the VLA and Arecibo data, both covering the full extent of IC 443, we have achieved an unprecedented combination of sensitivity and angular resolution, over the continuous range of angular scales from ~40'' to ~1°. Our new radio observations not only reveal previously unknown features of IC 443 but also show the details of the remnant more clearly. The radio morphology of IC 443 consists of two nearly concentric shells. Our 21 cm radio continuum data show that the two shells have distinctly different radial intensity distributions. This morphology supports the scenario whereby the western shell is a breakout portion of the remnant into a rarefied medium. We have developed a dynamical model accounting for the breakout, which provides an estimate for the remnant age of ~2 × 10<SUP>4</SUP> yr. The southeastern boundary of the remnant shows interesting features, seen in our observations for the first time: a faint radio continuum halo and numerous 'spurs.' These features are mainly found in the region where IC 443 overlaps with another remnant, G189.6+3.3. These features most likely originate from the interactions of IC 443 with the surrounding medium. The H <SPAN CLASS='sml'>I</SPAN> emission associated with IC 443 appears over the velocity range between −100 km s<SUP>−1</SUP> and 50 km s<SUP>−1</SUP>. The strongest absorption is seen around v<SUB>LSR</SUB> ~ −5 km s<SUP>−1</SUP>, which corresponds to the systemic velocity of IC 443. We identify a broad, extended lane of H <SPAN CLASS='sml'>I</SPAN> gas near the systemic velocity as preshock gas in the southern part of the remnant. Most of the shocked H <SPAN CLASS='sml'>I</SPAN> gas is located along the southern supernova remnant (SNR) boundary and is blueshifted. We derive an accurate mass of the shocked H <SPAN CLASS='sml'>I</SPAN> gas using template HCO<SUP>+</SUP> (1-0) spectra, which is 493 ± 56 M<SUB>☉</SUB>. Our high-resolution H <SPAN CLASS='sml'>I</SPAN> data enable us to resolve the shocked H <SPAN CLASS='sml'>I</SPAN> in the northeastern region into a few filamentary structures, which are well correlated with radiative filaments, in both position and velocity. This represents the first unambiguous detection of the recombined H <SPAN CLASS='sml'>I</SPAN> in an atomic shock. The characteristics of the filaments are not consistent with a clumpy shock model where the radiative signature is from dense clumps. Instead we propose that the shock has been propagating through a uniform medium of n<SUB>H</SUB> ~ 10 cm<SUP>−3</SUP>.</P>