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Public Participation and the New York City Title XX Planning Process: Its Perceived Impact and Efficacy
In a democracy, the concept of citizen participation is the essence of that system: it may not be an overstatement to declare that without citizen participation there is no democracy. The concept plays an important role in the study reported here. The writer examines a major element in the implementation of Title XX of the Social Security Act in New York City. The aim is to critically assess the perceived impact of the implementation of the citizen participation process of Title XX in New York City from 1979-1981. To accomplish this task, a survey focuses on citizen participation as this was acted out during July and August 1981. The information acquired illuminates the matter of who participated in the process, why they participated and what was the perceived impact of their participation.
Citizen participation and decentralization are issues which have become salient during historical periods. Clearly during the 1960s it characterized the thrust of southern blacks who demanded greater respect for their voting rights. It also had its echo in the cry for community control of schools in Brooklyn. There is no doubt that the concept of citizen participation was on the national agenda. By 1975 it was not clear if the two concepts, citizen participation and decentralization, had the same meaning as they did during the 1960s.
This study investigates the New York City Title XX citizen participation process, in general, the public hearings in particular. A total sample population of (47) made up of public officials (9), voluntary organization leaders (26), and community based advisory chairpersons (12) was examined through the use of quantitative and qualitative methodology. All respondents were interviewed, the interviews were tape recorded, the tapes were codified and a quotation bank was developed.
The findings suggest that a strong ambivalence tone is present. This perception transcends both the respondents' classification and race. On the manifest or decision making level the process was perceived as not efficacious. However, on the latent level long run benefits are viewed as a possibility. While the ambivalence, quantitatively, transcended race; qualitatively the black and white ambivalence appears to emerge from different perspectives.
In sum, this study shed some light on the Title XX citizen participation process from the point of view of those actively involved
Determining the Properties and Evolution of Red Galaxies from the Quasar Luminosity Function
(Abridged) We study the link between quasars and the red galaxy population
using a model for the self-regulated growth of supermassive black holes in
mergers involving gas-rich galaxies. Using a model for quasar lifetimes and
evolution motivated by hydrodynamical simulations of galaxy mergers, we
de-convolve the observed quasar luminosity function at various redshifts to
determine the rate of formation of black holes of a given final mass.
Identifying quasar activity with the formation of spheroids in the framework of
the merger hypothesis, this enables us to deduce the corresponding rate of
formation of spheroids with given properties as a function of redshift. This
allows us to predict, for the red galaxy population, the distribution of galaxy
velocity dispersions, the mass function, mass density, star formation rates,
the luminosity function in many observed wavebands (NUV, U, B, V, R, I, J, H,
K), the total red galaxy number density and luminosity density, the
distribution of colors as a function of magnitude and velocity dispersion for
several different wavebands, the distribution of mass to light ratios vs. mass,
the luminosity-size relations, and the typical ages and distribution of ages
(formation redshifts) as a function of both mass and luminosity. For each of
these quantities, we predict the evolution from redshift z=0-6. Each of our
predictions agrees well with existing observations, without the addition of
tunable parameters; the essential observational inputs come from the observed
quasar luminosity function. These predictions are skewed by several orders of
magnitude if we adopt simpler, traditional models of quasar lifetimes in which
quasars turn on/off or follow simple exponential light curves, instead of the
more complicated evolution implied by our simulations.Comment: 28 pages, 22 figures, matches version accepted to Ap
K+A Galaxies as the Aftermath of Gas-Rich Mergers: Simulating the Evolution of Galaxies as Seen by Spectroscopic Surveys
Models of poststarburst (or "K+A") galaxies are constructed by combining
fully three-dimensional hydrodynamic simulations of galaxy mergers with
radiative transfer calculations of dust attenuation. Spectral line catalogs are
generated automatically from moderate-resolution optical spectra calculated as
a function of merger progress in each of a large suite of simulations. The
mass, gas fraction, orbital parameters, and mass ratio of the merging galaxies
are varied systematically, showing that the lifetime and properties of the K+A
phase are strong functions of merger scenario. K+A durations are generally less
than ~0.1-0.3 Gyr, significantly shorter than the commonly assumed 1 Gyr, which
is obtained only in rare cases, owing to a wide variation in star formation
histories resulting from different orbital and progenitor configurations.
Combined with empirical merger rates, the model lifetimes predict
rapidly-rising K+A fractions as a function of redshift that are consistent with
results of large spectroscopic surveys, resolving tension between the observed
K+A abundance and that predicted when one assumes the K+A duration is the
lifetime of A stars (~1 Gyr). The effects of dust attenuation, viewing angle,
and aperture bias on our models are analyzed. In some cases, the K+A features
are longer-lived and more pronounced when AGN feedback removes dust from the
center, uncovering the young stars formed during the burst. In this picture,
the K+A phase begins during or shortly after the bright starburst/AGN phase in
violent mergers, and thus offers a unique opportunity to study the effects of
quasar and star formation feedback on the gas reservoir and evolution of the
remnant. Analytic fitting formulae are provided for the estimates of K+A
incidence as a function of merger scenario.Comment: 26 pages, 13 figures; ApJ; minor changes to reflect accepted versio
The imprint of dissipation on the shapes of merger remnant LOSVDs
The properties of elliptical galaxies are broadly consistent with simulated
remnants of gas-rich mergers between spirals, motivating more detailed studies
of the imprint of this formation mechanism on the remnant distribution
function. Gas has a strong impact on the non-Gaussian shapes of the
line-of-sight velocity distributions (LOSVDs) of the merger remnant, owing to
the embedded disk that forms out of the gas that retains its angular momentum
during the merger, and the strong central mass concentration from the gas that
falls to the center. The deviations from Gaussianity are parametrized by the
Gauss-Hermite moments h_3 and h_4, which are related to the skewness and
kurtosis of the LOSVDs. We quantify the dependence of the (h_3,h_4)-v/sigma
relations on the initial gas fraction of the progenitor disks in 1:1 mergers,
using Gadget-2 simulations including star formation, radiative cooling, and
feedback from supernovae and AGN. For gas fractions f_gas < ~15% the overall
correlation between h_3 and v/sigma is weak, consisting of a flat negatively
correlated component arising from edge-on viewing angles plus a steep
positively correlated part from face-on projections. The spread in v/sigma
values decreases toward high positive h_4, and there is a trend toward lower
h_4 as the gas fraction increases from 0 to 15%. For f_gas > ~20% the (h_3,4)-
v/sigma distributions look quite different - there is a tight negative h_3-
v/sigma correlation, and a wide spread in v/sigma values at all h_4, in better
agreement with observations. Re-mergers of the high-f_gas remnants (dry
mergers) produce slowly rotating systems with nearly Gaussian LOSVDs. We
explain all of these trends in terms of the underlying orbit structure of the
remnants, as molded by their dissipative formation histories.Comment: ApJ accepted - added some references and background on previous
studies. 9 pages, 4 figure
Star formation in galaxy mergers with realistic models of stellar feedback and the interstellar medium
We use hydrodynamic simulations with detailed, explicit models for stellar feedback to study galaxy mergers. These high-resolution (âŒ1âpc) simulations follow the formation and destruction of individual giant molecular clouds (GMC) and star clusters. We find that the final starburst is dominated by in situ star formation, fuelled by gas which flows inwards due to global torques. The resulting high gas density results in rapid star formation. The gas is self-gravitating, and forms massive (âČ10Âčâ°âM_â) GMC and subsequently super star clusters (with masses up to 10âžâM_â). However, in contrast to some recent simulations, the bulk of new stars which eventually form the central bulge are not born in super-clusters which then sink to the centre of the galaxy. This is because feedback efficiently disperses GMC after they turn severalâperâcent of their mass into stars. In other words, most of the mass that reaches the nucleus does so in the form of gas. The KennicuttâSchmidt law emerges naturally as a consequence of feedback balancing gravitational collapse, independent of the small-scale star formation microphysics. The same mechanisms that drive this relation in isolated galaxies, in particular radiation pressure from infrared photons, extend, with no fine-tuning, over seven decades in star formation rate (SFR) to regulate star formation in the most extreme starburst systems with densities âł10âŽâM_ââpcâ»ÂČ. This feedback also drives super-winds with large mass-loss rates; however, a significant fraction of the wind material falls back on to the discs at later times, leading to higher post-starburst SFRs in the presence of stellar feedback. This suggests that strong active galactic nucleus feedback may be required to explain the sharp cut-offs in SFR that are observed in post-merger galaxies.
We compare the results to those from simulations with no explicit resolution of GMC or feedback [âeffective equation-of-stateâ (EOS) models]. We find that global galaxy properties are similar between EOS and resolved-feedback models. The relic structure and mass profile, and the total mass of stars formed in the nuclear starburst are quite similar, as is the morphological structure during and after mergers (tails, bridges, etc.). Disc survival in sufficiently gas rich mergers is similar in the two cases, and the new models follow the same scalings as derived for the efficiency of disc re-formation after a merger as derived from previous work with the simplified EOS models. While the global galaxy properties are similar between EOS and feedback models, subgalaxy-scale properties and the SFRs can be quite different: the more detailed models exhibit significantly higher star formation in tails and bridges (especially in shocks), and allow us to resolve the formation of super star clusters. In the new models, the star formation is more strongly time-variable and drops more sharply between close passages. The instantaneous burst enhancement can be higher or lower, depending on the details of the orbit and initial structural properties of the galaxies; first-passage bursts are more sensitive to these details than those at the final coalescence
A Theoretical Interpretation of the Black Hole Fundamental Plane
We examine the origin and evolution of correlations between properties of
supermassive black holes (BHs) and their host galaxies using simulations of
major galaxy mergers, including the effects of gas dissipation, cooling, star
formation, and BH accretion and feedback. We demonstrate that the simulations
predict the existence of a BH 'fundamental plane' (BHFP), of the form M_BH
sigma^(3.0+-0.3)*R_e^(0.43+-0.19) or M_BH
M_bulge^(0.54+-0.17)*sigma^(2.2+-0.5), similar to relations found
observationally. The simulations indicate that the BHFP can be understood
roughly as a tilted intrinsic correlation between BH mass and spheroid binding
energy, or the condition for feedback coupling to power a pressure-driven
outflow. While changes in halo circular velocity, merger orbital parameters,
progenitor disk redshifts and gas fractions, ISM gas pressurization, and other
parameters can drive changes in e.g. sigma at fixed M_bulge, and therefore
changes in the M_BH-sigma or M_BH-M_bulge relations, the BHFP is robust. Given
the empirical trend of decreasing R_e for a given M_bulge at high redshift, the
BHFP predicts that BHs will be more massive at fixed M_bulge, in good agreement
with recent observations. This evolution in the structural properties of merger
remnants, to smaller R_e and larger sigma (and therefore larger M_BH,
conserving the BHFP) at a given M_bulge, is driven by the fact that bulge
progenitors have characteristically larger gas fractions at high redshifts.
Adopting the observed evolution of disk gas fractions with redshift, our
simulations predict the observed trends in both R_e(M_bulge) and M_BH(M_bulge).Comment: 22 pages, 19 figures, replaced with version accepted to ApJ.
Companion paper to arXiv:0707.400
The Luminosity Dependence of Quasar Clustering
We investigate the luminosity dependence of quasar clustering, inspired by
numerical simulations of galaxy mergers that incorporate black hole growth.
These simulations have motivated a new interpretation of the quasar luminosity
function. In this picture, the bright end of the quasar luminosity function
consists of quasars radiating nearly at their peak luminosities, while the
faint end consists mainly of very similar sources, but at dimmer phases in
their evolution. We combine this model with the statistics of dark matter halos
that host quasar activity. We find that, since bright and faint quasars are
mostly similar sources seen in different evolutionary stages, a broad range in
quasar luminosities corresponds to only a narrow range in the masses of quasar
host halos. On average, bright and faint quasars reside in similar host halos.
Consequently, we argue that quasar clustering should depend only weakly on
luminosity. This prediction is in qualitative agreement with recent
measurements of the luminosity dependence of the quasar correlation function
(Croom et al. 2005) and the galaxy-quasar cross-correlation function
(Adelberger & Steidel 2005). Future precision clustering measurements from SDSS
and 2dF, spanning a large range in luminosity, should provide a strong test of
our model.Comment: 9 pages, 4 figures, submitted to Ap
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