11,119 research outputs found
Creativity, dialogue, and place: Vitebsk, the early Bakhtin and the origins of the Russian avant-garde
This paper attempts to avoid both the ‘Bakhtinology’ that has become the basis of the ‘Bakhtin industry’ in Russia and the Americanization of his work as a “a sort of New Left celebrator of popular culture” (McLemee, 1997) to argue for a radical contextual understanding a set of relationships among Bakhtin, Malevich, Chagall and others. The appreciation of a Bakhtinian notion of the inherently creative use of language is used as a basis for the idea of the creative university as the ‘dialogical university’. The paper begins by exploring the connections between Bakhtin, Malevich and Chagall to explore the ontological sociality of artistic phenomena. A small town called Vitebsk in Belorussia experienced a flowering of creativity and artistic energy that led to significant modernist experimentation in the years 1917-1922 contribution to the birth of the Russian avant-garde. Marc Chagall, returning from the October Revolution took up the position of art commissioner and developed an academy of art that became the laboratory for Russian modernism. Chagall’s Academy, Bahktin’s Circle, Malevich’s experiments, artistic group UNOVIS, all in fierce dialogue with one another made the town of Vitebsk into an artistic crucible in the early twentieth century transforming creative energies of Russian drama, music, theatre, art, and philosophy in a distinctive contribution to modernism and also to a social understanding of creativity itself
Weak Gravitational Lensing and Cluster Mass Estimates
Hierarchical theories of structure formation predict that clusters of
galaxies should be embedded in a web like structure, with filaments emanating
from them to large distances. The amount of mass contained within such
filaments near a cluster can be comparable to the collapsed mass of the cluster
itself. Diffuse infalling material also contains a large amount of mass. Both
these components can contribute to the cluster weak lensing signal. This
``projection bias'' is maximized if a filament lies close to the line-of-sight
to a cluster. Using large--scale numerical simulations of structure formation
in a cosmological constant dominated cold dark matter model, we show that the
projected mass typically exceeds the actual mass by several tens of percent.
This effect is significant for attempts to estimate cluster masses through weak
lensing observations, and will affect weak lensing surveys aimed at
constructing the cluster mass function.Comment: 4 pages, 3 figures. LaTeX2e, uses emulateapj.sty and onecolfloat.sty.
To be submitted to the Astrophysical Journal Letter
Historical forest biomass dynamics modelled with Landsat spectral trajectories
Acknowledgements National Forest Inventory data are available online, provided by Ministerio de Agricultura, Alimentación y Medio Ambiente (España). Landsat images are available online, provided by the USGS.Peer reviewedPostprin
The Fourteenth Annual A.A. Sommer, Jr. Lecture on Corporate, Securities, and Financial Law at the Fordham Corporate Law Center
Hubble Advanced Camera for Surveys Observations of the z=6.42 Quasar SDSS 1148+5251: A Leak in the Gunn-Peterson Trough
The Hubble Advanced Camera for Surveys has been used to obtain a narrow-band
image of the weak emission peak seen at lambda=7205 A in the Gunn-Peterson Ly
beta absorption trough of the highest redshift quasar, SDSS J1148+5251. The
emission looks perfectly point-like; there is no evidence for the intervening
galaxy that we previously suggested might be contaminating the quasar spectrum.
We derive a more accurate astrometric position for the quasar in the two
filters and see no indication of gravitational lensing. We conclude that the
light in the Ly beta trough is leaking through two unusually transparent,
overlapping windows in the IGM absorption, one in the Ly beta forest at z ~ 6
and one in the Ly alpha forest at z ~ 5.
If there are significant optical depth variations on velocity scales small
compared with our spectral resolution (~150 km/s), the Ly alpha trough becomes
more transparent for a given Ly beta optical depth. Such variations can only
strengthen our conclusion that the fraction of neutral hydrogen in the IGM
increases dramatically at z>6. We argue that the transmission in the Ly beta
trough is not only a more sensitive measure of the neutral fraction than is Ly
alpha, it also provides a less biased estimator of the neutral hydrogen
fraction than does the Ly alpha transmission.Comment: Submitted to the Astronomical Journa
High redshift galaxies and the Lyman-alpha forest in a CDM universe
We use a cosmological hydrodynamic simulation of a cold dark matter universe
to investigate theoretically the relationship between high redshift galaxies
and the Lyman=alpha forest at redshift z=3. Galaxies in the simulation are
surrounded by halos of hot gas, which nevertheless contain enough neutral
hydrogen to cause a Ly-alpha flux decrement, its strength increasing with
galaxy mass. A comparison with recent observational data by Adelberger et. al
on the Ly-alpha forest around galaxies reveals that actual galaxies may have
systematically less Ly-alpha absorption within 1 Mpc of them than our simulated
galaxies. In order to investigate this possibility, we add several simple
prescriptions for galaxy feedback on the IGM to the evolved simulation. These
include the effect of photoionizing background radiation coming from galactic
sources, galactic winds whose only effect is to deposit thermal energy into the
IGM, and another, kinetic model for winds, which are assumed to evacuate
cavities in the IGM around galaxies. We find that only the latter is able to
produce a large effect, enough to match the tentative observational data, given
the energy available from star formation in the simulated galaxies. Another
intriguing possibility is that a selection effect is responsible, so that
galaxies with low
Ly-alpha absorption are preferentially included in the sample. This is also
viable, but predicts very different galaxy properties (including clustering)
than the other scenarios.Comment: Submitted to ApJ, 20 pages, 19 postscript figures, emulateapj.st
Probing the Ionization State of the Universe at z>6
We present high signal-to-noise ratio Keck ESI spectra of the two quasars
known to have Gunn-Peterson absorption troughs, SDSS J1030+0524 (z=6.28) and
SDSS J1148+5251 (z=6.37). The Ly alpha and Ly beta troughs for SDSS J1030+0524
are very black and show no evidence for any emission over a redshift interval
of ~0.2 starting at z=6. On the other hand, SDSS J1148+5251 shows a number of
emission peaks in the Ly beta Gunn-Peterson trough along with a single weak
peak in the Ly alpha trough. The Ly alpha emission has corresponding Ly beta
emission, suggesting that it is indeed a region of lower optical depth in the
intergalactic medium at z=6.08.
The stronger Ly beta peaks in the spectrum of SDSS J1148+5251 could
conceivably also be the result of "leaks" in the IGM, but we suggest that they
are instead Ly alpha emission from an intervening galaxy at z=4.9. This
hypothesis gains credence from a strong complex of C IV absorption at the same
redshift and from the detection of continuum emission in the Ly alpha trough at
the expected brightness. If this proposal is correct, the quasar light has
probably been magnified through gravitational lensing by the intervening
galaxy. The Stromgren sphere observed in the absorption spectrum of SDSS
J1148+5251 is significantly smaller than expected based on its brightness,
which is consistent with the hypothesis that the quasar is lensed.
If our argument for lensing is correct, the optical depths derived from the
troughs of SDSS J1148+5251 are only lower limits (albeit still quite strong,
with tau(LyA)>16 inferred from the Ly beta trough.) The Ly beta absorption
trough of SDSS J1030+0524 gives the single best measurement of the IGM
transmission at z>6, with an inferred optical depth tau(LyA)>22.Comment: To appear in July 2003 AJ, 34 pages, 11 figures; minor changes/typos
fixe
How Technology Fee Funding Transformed Collection Decisions at the University of Central Florida
Discovery of a Classic FR-II Broad Absorption Line Quasar from the FIRST Survey
We have discovered a remarkable quasar, FIRST J101614.3+520916, whose optical
spectrum shows unambiguous broad absorption features while its double-lobed
radio morphology and luminosity clearly indicate a classic Fanaroff-Riley Type
II radio source. Its radio luminosity places it at the extreme of the recently
established class of radio-loud broad absorption line quasars (Becker et al.
1997, 2000; Brotherton et al. 1998). Because of its hybrid nature, we speculate
that FIRST J101614.3+520916 is a typical FR-II quasar which has been
rejuvenated as a broad absorption line (BAL) quasar with a Compact Steep
Spectrum core. The direction of the jet axis of FIRST J101614.3+520916 can be
estimated from its radio structure and optical brightness, indicating that we
are viewing the system at a viewing angle of > 40 degrees. The position angles
of the radio jet and optical polarization are not well-aligned, differing by 20
to 30 degrees. When combined with the evidence presented by Becker et al.
(2000) for a sample of 29 BAL quasars showing that at least some BAL quasars
are viewed along the jet axis, the implication is that no preferred viewing
orientation is necessary to observe BAL systems in a quasar's spectrum. This,
and the probable young nature of compact steep spectrum sources, leads
naturally to the alternate hypothesis that BALs are an early stage in the lives
of quasars.Comment: 14 pages, 6 postscript figures; accepted for publication in the
Astrophysical Journa
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