Fish species associated with shipwreck and natural hard-bottom habitats from the middle to outer continental shelf of the Middle Atlantic Bight near Norfolk Canyon

Fish species of the Middle Atlantic Bight (MAB) continental shelf are well known; however, species occupying hard-bottom habitats, particularly on the outer shelf, are poorly documented. Reef-like habitats are relatively uncommon on the MAB shelf; therefore, shipwrecks may represent a significant habitat resource. During fall 2012 and spring 2013, 9 sites (depths: 42–126 m) near Norfolk Canyon were surveyed by using remotely operated vehicles. One site consisted of sand bottom, one consisted of predominantly natural hard bottom, and 7 sites included 8 large shipwrecks. Of 38 fish taxa identified, 33 occurred on hard bottom and 25 occurred on soft substrata. Fourteen fish taxa occurred almost exclusively on hard bottom, and 6 species were observed only on soft bottom. The most abundant taxa, especially on reef habitat, were the chain dogfish (Scyliorhinus retifer), a scorpionfish (Scorpaena sp.), the yellowfin bass (Anthias nicholsi), the red barbier (Baldwinella vivanus), the black sea bass (Centropristis striata), unidentified anthiine serranids, and the deepbody boarfish (Antigonia capros). Depth, location, and season did not significantly influence fish assemblages. Fish assemblages on natural and artificial hard-bottom habitat were similar but significantly different from soft-bottom assemblages. Deep-reef fishes of the southern MAB may be constrained by zoogeography, depth, and inadequate habitat— limitations that could increase their vulnerability

Prospectus, April 20, 1988

https://spark.parkland.edu/prospectus_1988/1014/thumbnail.jp

Prospectus, March 16, 1988

https://spark.parkland.edu/prospectus_1988/1009/thumbnail.jp

Gemini/GMOS Imaging of Globular Cluster Systems in Five Early-type Galaxies

This paper presents deep high quality photometry of globular cluster (GC) systems belonging to five early-type galaxies covering a range of mass and environment. Photometric data were obtained with the Gemini North and Gemini South telescopes in the filter passbands g', r', and i'. The combination of these filters with good seeing conditions allows an excellent separation between GC candidates and unresolved field objects. Bimodal GC colour distributions are found in all five galaxies. Most of the GC systems appear bimodal even in the (g' -r') vs (r' -i') plane. A population of resolved/marginally resolved GC and Ultra Compact Dwarf candidates was found in all the galaxies. A search for the so-called "blue tilt" in the colour-magnitude diagrams reveals that NGC 4649 clearly shows that phenomenon although no conclusive evidence was found for the other galaxies in the sample. This "blue tilt" translates into a mass-metallicity relation given by Z \propto M^0.28\pm0.03 . This dependence was found using a new empirical (g' -i') vs [Z/H] relation which relies on an homogeneous sample of GC colours and metallicities. This paper also explores the radial trends in both colour and surface density for the blue (metal-poor) and red (metal-rich) GC subpopulations. As usual, the red GCs show a steeper radial distribution than the blue ones. Evidence of galactocentric colour gradients is found in some of the GC systems, being more significant for the two S0 galaxies in the sample. Red GC subpopulations show similar colours and gradients to the galaxy halo stars in their inner region. A GC mean colour-galaxy luminosity relation, consistent with [Z/H] \propto L_B ^0.26\pm0.08, is present for the red GCs. An estimate of the total GC populations and specific frequency SN values is presented for NGC 3115, NGC 3379, NGC 3923 and NGC 4649.Comment: 23 pages, 13 figures and 9 tables. Tables A1 and A2 will be published in full online only. Accepted for publication in MNRA

Multi-messenger searches via IceCube’s high-energy neutrinos and gravitational-wave detections of LIGO/Virgo

We summarize initial results for high-energy neutrino counterpart searches coinciding with gravitational-wave events in LIGO/Virgo\u27s GWTC-2 catalog using IceCube\u27s neutrino triggers. We did not find any statistically significant high-energy neutrino counterpart and derived upper limits on the time-integrated neutrino emission on Earth as well as the isotropic equivalent energy emitted in high-energy neutrinos for each event

In-situ estimation of ice crystal properties at the South Pole using LED calibration data from the IceCube Neutrino Observatory

The IceCube Neutrino Observatory instruments about 1 km3 of deep, glacial ice at the geographic South Pole using 5160 photomultipliers to detect Cherenkov light emitted by charged relativistic particles. A unexpected light propagation effect observed by the experiment is an anisotropic attenuation, which is aligned with the local flow direction of the ice. Birefringent light propagation has been examined as a possible explanation for this effect. The predictions of a first-principles birefringence model developed for this purpose, in particular curved light trajectories resulting from asymmetric diffusion, provide a qualitatively good match to the main features of the data. This in turn allows us to deduce ice crystal properties. Since the wavelength of the detected light is short compared to the crystal size, these crystal properties do not only include the crystal orientation fabric, but also the average crystal size and shape, as a function of depth. By adding small empirical corrections to this first-principles model, a quantitatively accurate description of the optical properties of the IceCube glacial ice is obtained. In this paper, we present the experimental signature of ice optical anisotropy observed in IceCube LED calibration data, the theory and parametrization of the birefringence effect, the fitting procedures of these parameterizations to experimental data as well as the inferred crystal properties.</p