305 research outputs found
Studying the Binding of Portland State’s Codex to Localize Production
This paper examines Portland State’s 1490 codex as a material object by studying the stamp designs on its covers to determine where and when it may have been bound.
Four stamp designs are discernible, and these were compared to rubbings of stamp designs from fifteenth- and sixteenth-century incunable bindings in the Einbanddatenbank and Scott Husby Database. The findings from this study point to Erfurt, Germany, and more specifically the workshop of Nicolaus von Havelberg (active 1477–1506), as the probable binding site.https://pdxscholar.library.pdx.edu/mmft_extratextual/1006/thumbnail.jp
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The Effect of a Growing Black Hole on the Infrared Emission of Dusty Galaxies in the Distant Universe
The buildup of stellar and black hole mass peaked during z=1-3. Infrared (IR) luminous galaxies, which are massive and heavily dust obscured (LIR \u3e 1011 Lsun), dominate the stellar growth during this era, and many are harboring a hidden active galactic nucleus (AGN). We have quantified the contribution of AGN heating to the infrared emission of a large sample of dusty, luminous galaxies from z=0.5-4 using Spitzer mid-IR spectroscopy, available for every source. We classify sources as star forming galaxies, AGN, or composites based on the presence of mid-IR continuum emission due to a dusty torus. 60% of our sample shows signs of some dust heating emanating from an AGN, and that an AGN is clearly linked with increasing dust temperatures. We quantify the far-IR emission using deep Herschel imaging and find that the strength of mid-IR AGN emission is tightly correlated with the total contribution of an AGN to LIR, which has important consequences for calculating star formation rates in dusty high redshift galaxies. We calibrate techniques to remove the contribution of AGN to LIR. Because of dust obscuration, much of this AGN activity is undetected at other wavelengths, but we present new color diagnostics to effectively identify heavily obscured AGN. We discuss the role that mergers might play in fueling AGN growth and find our galaxies to be generally consistent with the picture that a major merger triggers an AGN. We test what effect an IR luminous AGN has on the star formation efficiency (the star formation rate compared with the molecular gas mass) using a pilot sample of 24 galaxies at
Evaluation of an attached growth organic media bioreactor for swine waste treatment and odor abatement
The objective of this study was to determine if an organic media attached growth bioreactor could effectively be used as a means of odor control for swine waste. The pilot-scale attached growth bioreactor system was evaluated against a standard pit recharge system, which served as the control. Performance was based on water quality testing, odor assessments by a human sensory panel, and air phase measurements of ammonia and hydrogen sulfide. The affect of aeration on the system was also evaluated, along with various types of organic media (kenaf, hardwood mulch, and corncobs). Overall, the bioreactor systems were effective in reducing orthophosphate, COD, volatile acids, and phenol concentrations as compared to the control. The bioreactor systems were not effective in reducing the conductivity, ammonia or total solids concentration of the wastewater. With the exception of the corncob media, all bioreactor systems significantly reduced the overall odor intensity and the fecal characteristic of the wastewater as compared to the control system
AGN's Deadness Over Cosmic Time: UVJ Diagrams of X-Ray-Selected AGN
Active Galactic Nuclei (AGN) are intensely accreting supermassive black holes
at the centers of massive galaxies. Though these objects occupy little spatial
extent of the galaxy itself, they are thought to have far reaching affects,
impacting the galaxy's star formation, and possibly it's lifespan until it
becomes 'red and dead'. Typical galaxies demonstrate that, over cosmic time,
they tend to separate into a bimodal distribution of 'red and dead' or blue and
star forming. We examine whether active galaxies evolve over cosmic time in a
similar way, and whether this can reveal anything about the complexities of the
relationship between an AGN and the host galaxy. We use the Stripe82X survey to
identify 3940 X-ray AGN spanning z=0-2.5, and we measure the rest-frame UVJ
colors of each galaxy. We classify AGN as star-forming or quiescent based on
their location in a UVJ color diagram. We find that there is not a clear
bimodal distribution between AGN in star forming and quiescent galaxies.
Furthermore, the most luminous X-ray sources tend to lie in the star forming
region, which may indicate a correlation between central engine activity and
increased rates of star formation.Comment: 4 pages, 1 figur
Supporting Pregnant Persons: The Benefits of Opening a Birth Centre in London, Ontario (Dynamic Doulas of London)
An ngVLA Wide Area AGN Survey
The next generation Very Large Array (ngVLA) will have unprecedented
sensitivities and mapping speeds at GHz. We discuss how the active
galactic nuclei (AGN) community can benefit from a wide-area, medium depth
ngVLA survey. We propose a 10 deg survey in the Stripe 82 field using the 8
GHz band with an rms depth of Jy beam. We will detect
130,000 galaxies, including radio-quiet AGN out to . We can
measure the luminosity and space density evolution of radio-quiet and
radio-loud AGN. We can also measure AGN evolution through clustering of both
populations using cross-correlation functions. A wide area ngVLA survey will
benefit from existing multiwavelength AGN populations, particularly in the
Stripe 82 field, as well as new information from next-generation optical and
infrared survey instruments such as LSST and WFIRST.Comment: ngVLA Science Use Case to appear in the ngVLA Science Book
(http://ngvla.nrao.edu/page/scibook
Deep 2MASS Photometry of M67 and Calibration of the Main Sequence J-Ks Color Difference as an Age Indicator
We present an analysis of Two Micron All Sky Survey (2MASS) calibration
photometry of the old open cluster M67 (NGC 2682). The proper motion-cleaned
color-magnitude diagram (CMD) resulting from these data extends ~3 magnitudes
deeper than one based on data from the point source catalog. The CMD extends
from above the helium-burning red clump to a faint limit that is more than 7
magnitudes below the main sequence turnoff in the Ks band. After adopting a
reddening of E(B-V) = 0.041 +/- 0.004 and a metal abundance of [Fe/H] = -0.009
+/- 0.009 based on a survey of published values, we fit the unevolved main
sequence of M67 to field main sequence stars with 2MASS photometry and
Hipparcos parallaxes. This analysis yields distance moduli of (m-M)Ks = 9.72
+/- 0.05 and (m-M)o = 9.70 +/- 0.05, which are consistent with published
values. We compare the theoretical isochrones of Girardi et al. and Dotter et
al. to the CMD of M67 and comment on the relative merits of each set of models.
These comparisons suggest an age between 3.5 and 4.0 Gyr for M67. The depth of
the M67 data make them ideal for the calibration of a new age indicator that
has recently been devised by Calamida et al.- the difference in (J-Ks) color
between the main sequence turnoff (TO) and the point on the lower main sequence
where it turns down (TD) and becomes nearly vertical [D(J-Ks)]. Coupled with
deep 2MASS photometry for three other open clusters, NGC 2516, M44, and NGC
6791, we calibrate D(J-Ks) in terms of age and find D(J-Ks) = (3.017 +/- 0.347)
- (0.259 +/- 0.037)*Log Age (yrs).Comment: 19 pages, 9 figures, accepted for publication in The Astrophysical
Journa
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