3 research outputs found
Spatially Extended Low Ionization Emission Regions (LIERs) at
We present spatially resolved emission diagnostics for eight
galaxies that demonstrate extended low ionization emission-line regions (LIERs)
over kpc scales. Eight candidates are selected based on their spatial extent
and emission line fluxes from slitless spectroscopic observations with the
HST/WFC3 G141 and G800L grisms in the well-studied GOODS survey fields. Five of
the candidates (62.5%) are matched to X-ray counterparts in the \textit{Chandra
X-Ray Observatory} Deep Fields. We modify the traditional
Baldwin-Philips-Terlevich (BPT) emission line diagnostic diagram to use
[SII]/(H+[NII]) instead of [NII]/H to overcome the blending of
[NII] and H+[NII] in the low resolution slitless grism spectra. We
construct emission line ratio maps and place the individual pixels in the
modified BPT. The extended LINER-like emission present in all of our
candidates, coupled with X-Ray properties consistent with star-forming galaxies
and weak [OIII]5007\AA\ detections, is inconsistent with purely
nuclear sources (LINERs) driven by active galactic nuclei. While recent
ground-based integral field unit spectroscopic surveys have revealed
significant evidence for diffuse LINER-like emission in galaxies within the
local universe , this work provides the first evidence for the
non-AGN origin of LINER-like emission out to high redshifts.Comment: 11 pages, 1 table, 6 figures, accepted for publication in the
Astrophysics Journal (ApJ
An assessment of the reliability of cut surface characteristics to distinguish between hand-powered reciprocating saw blades in cases of experimental dismemberment
Criminal dismemberment is most commonly committed with a variety of handâpowered saws. These saws leave characteristic marks upon the bone that can assist in the identification of the weapon utilized. The current study provides frequencies of presentation of ten cut surface characteristics and examines intraâ and interindividual variation between three handâpowered reciprocating saws. Pig radii were used as a proxy for human remains. 42 cut surfaces were created with three handâpowered reciprocating saws by the same researcher. Cut surface characteristics were assessed macroscopically, microscopically and with Scanning Electron Microscope (SEM), as well as photographed with Reflectance Transformation Imaging (RTI). Cut surface polish is the only characteristic that demonstrates consistently significant difference between saws. Five characteristics demonstrate some variation between blades: entrance shaving, breakaway spurs, breakaway notches, pullâout striae, and tooth hop. Four characteristics demonstrate no difference between blades: cut surface striation shape, cut surface striation regularity, harmonics, and exit chipping. Tooth hop is the most reliable characteristic for differentiating between blades in this study, while pullâout striae demonstrates high intraâindividual variability and a low frequency of presentation making it unreliable for differentiating between saw blades. Cut surface striations, exit chipping, and breakaway spurs occurred with the highest frequencies and were reliable for determining direction of blade progress and blade stroke, but were not reliable for differentiating between saw blades. Harmonics were absent. Further research is necessary to create large databases of known saw mark examples with known intraâ and interindividual variability rates and error rates