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THE MEGAMASER COSMOLOGY PROJECT. IX. BLACK HOLE MASSES FOR THREE MASER GALAXIES
Gao, F.,Braatz, J. A.,Reid, M. J.,Condon, J. J.,Greene, J. E.,Henkel, C.,Impellizzeri, C. M. V.,Lo, K. Y.,Kuo, C. Y.,Pesce, D. W.,Wagner, J.,Zhao, W. American Astronomical Society 2017 The Astrophysical journal Vol.834 No.1
<P>As part of the Megamaser Cosmology Project, we present VLBI maps of nuclear water masers toward five galaxies. The masers originate in sub-parsec circumnuclear disks. For three of the galaxies, we fit Keplerian rotation curves to estimate their supermassive black hole (SMBH) masses, and determine (2.9 +/- 0.3) x 10(6)M(Theta) for J0437+2456, (1.7 +/- 0.1) x 10(7)M(Theta) for ESO 558-G009, and (1.1 +/- 0.2) x 10(7)M(Theta) for NGC 5495. In the other two galaxies, Mrk 1029 and NGC 1320, the geometry and dynamics are more complicated and preclude robust black hole mass estimates. Including our new results, we compiled a list of 15 VLBI-confirmed disk maser galaxies with robust SMBH mass measurements. With this sample, we confirm the empirical relation of R-out proportional to 0.3M(SMBH) reported in Wardle & Yusef-Zadeh. We also find a tentative correlation between maser disk outer radii and Wide-Field Infrared Survey Explorer luminosity. We find no correlations of maser disk size with X-ray 2-10 keV luminosity or [O III] luminosity.</P>
Green, Joel D.,Evans II, Neal J.,Jørgensen, Jes K.,Herczeg, Gregory J.,Kristensen, Lars E.,Lee, Jeong-Eun,Dionatos, Odysseas,Yildiz, Umut A.,Salyk, Colette,Meeus, Gwendolyn,Bouwman, Jeroen,Visser, Ruu IOP Publishing 2013 The Astrophysical journal Vol.770 No.2
<P>We present 50-210 mu m spectral scans of 30 Class 0/I protostellar sources, obtained with Herschel-PACS, and 0.5-1000 mu m spectral energy distributions, as part of the Dust, Ice, and Gas in Time Key Program. Some sources exhibit up to 75 H2O lines ranging in excitation energy from 100 to 2000 K, 12 transitions of OH, and CO rotational lines ranging from J = 14 -> 13 up to J = 40 -> 39. [O I] is detected in all but one source in the entire sample; among the sources with detectable [O I] are two very low luminosity objects. The mean 63/145 mu m [O I] flux ratio is 17.2 +/- 9.2. The [O I] 63 mu m line correlates with L-bol, but not with the time-averaged outflow rate derived from low-J CO maps. [C II] emission is in general not local to the source. The sample L-bol increased by 1.25 (1.06) and T-bol decreased to 0.96 (0.96) of mean (median) values with the inclusion of the Herschel data. Most CO rotational diagrams are characterized by two optically thin components (< N > = ( 0.70 +/- 1.12) x 10(49) total particles). N-CO correlates strongly with L-bol, but neither T-rot nor N-CO(warm)/N-CO(hot) correlates with L-bol, suggesting that the total excited gas is related to the current source luminosity, but that the excitation is primarily determined by the physics of the interaction (e.g., UV-heating/shocks). Rotational temperatures for H2O (< T-rot > = 194 +/- 85 K) and OH (< T-rot > = 183 +/- 117 K) are generally lower than for CO, and much of the scatter in the observations about the best fit is attributed to differences in excitation conditions and optical depths among the detected lines.</P>
MEGAMASER DISKS REVEAL A BROAD DISTRIBUTION OF BLACK HOLE MASS IN SPIRAL GALAXIES
Greene, J. E.,Seth, A.,Kim, M.,Lä,sker, R.,Goulding, A.,Gao, F.,Braatz, J. A.,Henkel, C.,Condon, J.,Lo, K. Y.,Zhao, W. American Astronomical Society 2016 ASTROPHYSICAL JOURNAL LETTERS - Vol.826 No.2
<P>We use new precision measurements of black hole (BH) masses from water megamaser disks to investigate scaling relations between macroscopic galaxy properties and supermassive BH mass. The megamaser-derived BH masses span 10(6)-10(8) M-circle dot, while all the galaxy properties that we examine (including total stellar mass, central mass density, and central velocity dispersion) lie within a narrower range. Thus, no galaxy property correlates tightly with M-BH in similar to L* spiral galaxies as traced by megamaser disks. Of them all, stellar velocity dispersion provides the tightest relation, but at fixed sigma* the mean megamaser M-BH are offset by -0.6 +/- 0.1 dex relative to early-type galaxies. Spiral galaxies with non-maser dynamical BH masses do not appear to show this offset. At low mass, we do not yet know the full distribution of BH mass at fixed galaxy property; the non-maser dynamical measurements may miss the low-mass end of the BH distribution due to an inability to resolve their spheres of influence and/or megamasers may preferentially occur in lower-mass BHs.</P>
Green, R.J.,Hunt, A.,Zatsepin, D.A.,Boukhvalov, D.W.,McLeod, J.A.,Kurmaev, E.Z.,Skorikov, N.A.,Gavrilov, N.V.,Moewes, A. North-Holland 2012 Journal of non-crystalline solids Vol.358 No.23
The electronic structures of Sn and Pb implanted SiO<SUB>2</SUB> are studied using soft X-ray absorption (XAS) and emission (XES) spectroscopy. We show, using reference compounds and ab initio calculations, that the presence of Pb?O and Sn?O interactions can be detected in the pre-edge region of the oxygen K-edge XAS. Via analysis of this interaction-sensitive pre-edge region, we find that Pb implantation results primarily in the clustering of Pb atoms. Conversely, with Sn implantation using identical conditions, strong Sn?O interactions are present, showing that Sn is coordinated with oxygen. The varying results between the two ion types are explained using both ballistic considerations and density functional theory calculations. We find that the substitution of Pb into Si sites in SiO<SUB>2</SUB> requires much more energy than substituting Sn in these same sites, primarily due to the larger size of the Pb ions. From these calculated formation energies it is evident that Pb requires far higher temperatures than Sn to be soluble in SiO<SUB>2</SUB>. These results help explain the complex processes which take place upon implantation and determine the final products.
Local Structure of Fe Impurity Atoms in ZnO: Bulk versus Surface
McLeod, J. A.,Boukhvalov, D. W.,Zatsepin, D. A.,Green, R. J.,Leedahl, B.,Cui, L.,Kurmaev, E. Z.,Zhidkov, I. S.,Finkelstein, L. D.,Gavrilov, N. V.,Cholakh, S. O.,Moewes, A. American Chemical Society 2014 The Journal of Physical Chemistry Part C Vol.118 No.10
<P>By studying Fe-doped ZnO pellets and thin films with various X-ray spectroscopic techniques, and complementing this with density functional theory calculations, we find that Fe-doping in bulk ZnO induces isovalent (and isostructural) cation substitution (Fe<SUP>2+</SUP> → Zn<SUP>2+</SUP>). In contrast to this, Fe-doping near the surface produces both isovalent and heterovalent substitution (Fe<SUP>3+</SUP> → Zn<SUP>2+</SUP>). The calculations performed herein suggest that the most likely defect structure is the single or double substitution of Zn with Fe, although, if additional oxygen is available, then Fe substitution with interstitial oxygen is even more energetically favorable. Furthermore, it is found that ferromagnetic states are energetically unfavorable, and ferromagnetic ordering is likely to be realized only through the formation of a secondary phase (i.e., ZnFe<SUB>2</SUB>O<SUB>4</SUB>), or codoping with Cu.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2014/jpccck.2014.118.issue-10/jp411219z/production/images/medium/jp-2013-11219z_0010.gif'></P>
Epitaxy of Si and Si₁_xGex(001) by ultrahigh vacuum ion - beam sputter deposition
N.-E. Lee,J. E. Greene 한국진공학회(ASCT) 1998 Journal of Korean Vacuum Science & Technology Vol.2 No.2
Epitaxial undoped and Sb-doped Si films have been grown on Si(001) substrates at temperatures T_s between 80 and 750℃ using energetic Si in ultra-high-vacuum Kr^+-ion-beam sputter deposition(IBSD). Critical epitaxial thicknesses t_e, the average thickness of epitaxial layers, in undoped films were found to range from 8 nm at T_s=80℃ to >1.2 μm at T_s=300℃ while Sb incorporation probabilities σ_(sb) varied from unity at T_s<~550℃ to ~_0.1 at 750℃. These t_e and σ_(sb) values are approximately one and one-to-three orders of magnitude, respectively, higher than reported results achieved with molecular-beam epitaxy. Plan-view and cross-sectional transmission electron microscopy, high-resolution x-ray diffraction, channeling and axial angular-yield profiles by Rutherford backscattering spectroscopy for epitaxial Si_(1-x)Ge_x(001) alloy films (0.15≤x≤0.30) demonstrated that the films are of extremely high crystalline quality. Critical layer thicknesses h_s, the film thickness where strain relaxation starts, in these alloys were found to increase rapidly with decreasing growth temperature. For Si_(0.70)Ge_(0.30), h_c ranged from ~_35 nm at T_s=550℃ to ~_650 nm at 350℃ compared to an equilibrium value of 8 nm.