Identifying Compact Symmetric Objects in the Southern Sky

We present results of multifrequency polarimetric VLBA observations of 20 compact radio sources. The observations represent the northern and southern extensions of a large survey undertaken to identify Compact Symmetric Objects (CSOs) Observed in the Northern Sky (COINS). CSOs are young radio galaxies whose jet axes lie close to the plane of the sky, and whose appearance is therefore not dominated by relativistic beaming effects. The small linear sizes of CSOs make them valuable for studies of both the evolution of radio galaxies and testing unified schemes for active galactic nuclei (AGN). In this paper we report on observations made of 20 new CSO candidates discovered in the northern and southern extremities of the VLBA Calibrator Survey. We identify 4 new CSOs, and discard 12 core-jet sources. The remaining 4 sources remain candidates pending further investigation. We present continuum images at 5 GHz and 15 GHz and, where relevant, images of the polarized flux density and spectral index distributions for the 8 new CSOs and CSO candidates.Comment: accepted to Ap

A Compact Supermassive Binary Black Hole System

We report on the discovery of a supermassive binary black hole system in the radio galaxy 0402+379, with a projected separation between the two black holes of just 7.3 pc. This is the closest black hole pair yet found by more than two orders of magnitude. These results are based upon recent multi-frequency observations using the Very Long Baseline Array (VLBA) which reveal two compact, variable, flat-spectrum, active nuclei within the elliptical host galaxy of 0402+379. Multi-epoch observations from the VLBA also provide constraints on the total mass and dynamics of the system. Low spectral resolution spectroscopy using the Hobby-Eberly Telescope indicates two velocity systems with a combined mass of the two black holes of ~1.5 x 10^8 solar masses. The two nuclei appear stationary while the jets emanating from the weaker of the two nuclei appear to move out and terminate in bright hot spots. The discovery of this system has implications for the number of close binary black holes that might be sources of gravitational radiation. Green Bank Telescope observations at 22 GHz to search for water masers in this interesting system are also presented.Comment: 34 pages, 7 figures, Accepted to The Astrophysical Journa

New Record for \u3ci\u3eWoldstedtius flavolineatus\u3c/i\u3e (Ichneumonidae: Diplazontinae), a Hymenopteran Parasitoid of Syrphid Flies in Hawaii

The parasitoid wasp Woldstedtius flavolineatus (Gravenhorst) (Ichneumonidae) attacks the larvae of syrphid flies (Syrphidae). Woldstedtius flavolineatus was collected in Hawaii for the first time during an extensive malaise trap-based survey of parasitoids in Hawaiian forests. Since its initial collection on Hawaii Island in January 2006, it has been collected at five additional sites on Hawaii Island and at one site each on Maui and Oahu. Malaise trap results from Hakalau Forest National Wildlife Refuge showed a strong seasonal pattern of abundance, with peak population levels reached during July–September. Rearing of its host, Allograpta obliqua (Say), collected from koa (Acacia koa Gray) at Hakalau over two days, revealed a parasitism rate of approximately 95%. Broader impacts of this alien wasp are unknown, but a reduction in host syrphid abundance could result in an increase in numbers of psyllids and aphids (Homoptera) that are preyed upon by syrphid larvae. Furthermore, a reduction in adult syrphids could impact the reproductive success of some of the plants they pollinate

P3_4 Elysium: Where'd the Atmosphere Go?

This paper determines whether the Elysium space station, from the 2013 film Elysium[1], could maintain an atmosphere. We found that Elysium, with a radius of 20 km[2], would not hold onto its atmosphere unless high wind speeds (183 ms^-1, 324 ms^-1, and 443 ms^-1; for the atmospheric rotations tested) are to be endured by its inhabitants

P3_6 Cavorite Pt 2: the Gravity of the Situation

We continue to explore the gravitational and atmospheric effects of Cavorite, a fictional material that is “opaque to gravitation”, by attempting to form a simplified gravitational model of the situation. This gravitational model was found to define the range at which gravitational acceleration will return to near normal as between 0.02 and 12 m. Further research is required to truly model the gravitational acceleration due to Cavorite

P3_3 On the Atmospheric Effects of Cavorite

We estimate the gravitational and atmospheric effects of a fictional substance known as Cavorite, a material proposed by H.G. Wells that is “opaque to gravitation”. We conclude that for a Cavorite sheet of radius 1 m the impact on the gravitational acceleration is only meaningful at less than 12 m above the plate, and is insignificant at heights greater than this. Therefore, the atmosphere is unlikely to vent away as claimed

P3_9 Scooby and Shaggy: Metabolic Miracles

In the cartoon `What's New Scooby-Doo?' the characters Shaggy and Scooby are seen to eat large volumesof food without gaining any weight. Their effective temperatures in order to radiate away the excess energywere calculated to be T_Sh ~ 97 ± 033 °C for Shaggy, and T_Sc ~ 140 ± 43 °C for Scooby. It was concludedthat under normal circumstances, the subjects would perish of extreme hyperthermia. It was also notedthat Shaggy could survive if he was able to sweat continuously at the maximum rate for a human

P3_1 On the feasibility of neutrino sails

In this paper we consider whether a neutrino sail, a sheet of material absorbing neutrinos and gaining thrust from their momentum change, is a viable method of spacecraft propulsion. We calculate the thrust that could be achieved per unit area and compare this to that possible using a photon solar sail. We also calculate the thickness of sail necessary assuming that there are no special conditions under which the cross section for neutrino interactions with nuclei can be increased. We find that a thickness of 34000 light years would be necessary if a sheet of osmium were used, whereas neutron star matter could achieve this at 189 km thickness. We conclude that a neutrino sail is not a practical method of propulsion