Seyfert galaxies with Swift: giant flares, rapid drops, and other surprises

Swift has initiated a new era of understanding the extremes of active galactic nuclei (AGN) variability, their drivers and underlying physics. This is based on its rapid response, high sensitivity, good spatial resolution, and its ability to collect simultaneously X--ray-to-optical SEDs. Here, we present results from our recent monitoring campaigns with Swift of highly variable AGN, including outbursts, deep low states, and unusual long-term trends in several Seyfert galaxies including Mrk 335, WPVS007, and RXJ2314.9+2243. We also report detection of a new X-ray and optical outburst of IC 3599 and our Swift follow-ups. IC 3599 was previously known as one of the AGN with the highest-amplitude outbursts. We briefly discuss implications of this second outburst of IC 3599 for emission scenarios including accretion-disk variability, repeat tidal disruption events, and the presence of a binary supermassive black hole.Comment: to appear in "Swift: 10 years of discovery", Proceedings of Scienc

High-energy neutrino fluxes from AGN populations inferred from X-ray surveys

High-energy neutrinos and photons are complementary messengers, probing violent astrophysical processes and structural evolution of the Universe. X-ray and neutrino observations jointly constrain conditions in active galactic nuclei (AGN) jets: their baryonic and leptonic contents, and particle production efficiency. Testing two standard neutrino production models for local source Cen A \citep{KT2008,BB2009}, we calculate the high-energy neutrino spectra of single AGN sources and derive the flux of high-energy neutrinos expected for the current epoch. Assuming that accretion determines both X-rays and particle creation, our parametric scaling relations predict neutrino yield in various AGN classes. We derive redshift-dependent number densities of each class, from {\it Chandra} and {\it Swift}/BAT X-ray luminosity functions \citep{SGB2008,ACS2009}. We integrate the neutrino spectrum expected from the cumulative history of AGN (correcting for cosmological and source effects, e.g. jet orientation and beaming). Both emission scenarios yield neutrino fluxes well above limits set by {\it IceCube} (by $\sim 4$--$10^6 \times$ at 1 PeV, depending on the assumed jet models for neutrino production). This implies that: (i) Cen A might not be a typical neutrino source as commonly assumed; (ii) both neutrino production models overestimate the efficiency; (iii) neutrino luminosity scales with accretion power differently among AGN classes and hence does not follow X-ray luminosity universally; (iv) some AGN are neutrino-quiet (e.g. below a power threshold for neutrino production); (v) neutrino and X-ray emission have different duty cycles (e.g. jets alternate between baryonic and leptonic flows); or (vi) some combination of the above.Comment: 16 pages, 6 figures, 3 tables, accepted for publication in MNRA

Scaling law in target-hunting processes

We study the hunting process for a target, in which the hunter tracks the goal by smelling odors it emits. The odor intensity is supposed to decrease with the distance it diffuses. The Monte Carlo experiment is carried out on a 2-dimensional square lattice. Having no idea of the location of the target, the hunter determines its moves only by random attempts in each direction. By sorting the searching time in each simulation and introducing a variable $x$ to reflect the sequence of searching time, we obtain a curve with a wide plateau, indicating a most probable time of successfully finding out the target. The simulations reveal a scaling law for the searching time versus the distance to the position of the target. The scaling exponent depends on the sensitivity of the hunter. Our model may be a prototype in studying such the searching processes as various foods-foraging behavior of the wild animals.Comment: 7 figure

AN IRRIGATION MODEL FOR MANAGEMENT OF LIMITED WATER SUPPLIES

A two-stage simulation/mathematical programming model is presented for determining the optimal intraseasonal allocation of irrigation water under conditions of limited water supply. The model is applied to a series of water shortage scenarios under both surface and center pivot irrigation. Economically efficient irrigation management is shown to involve the coordination of a number of managerial decisions, including irrigation scheduling, crop substitution, the adoption of improved irrigation labor practices, and idling land. The results indicate that significant opportunities exist for conserving water in the study area under both surface and center pivot irrigation.Crop Production/Industries, Resource /Energy Economics and Policy,

Color television study Final report, Nov. 1965 - Mar. 1966

Color television camera for transmission from lunar and earth orbits and lunar surfac

Adhesives for laminating polyimide insulated flat conductor cable

Polymer adhesive laminates polyimide-film flat conductor cable. It is obtained by reacting an appropriate diamine with a dianhydride. The adhesive has also been used in the lamination of copper to copper for the preparation of multilayer circuit boards

Use of soil moisture information in yield models

There are no author-identified significant results in this report

Historical Demography and Genetic Population Structure of the Blackfin Tuna (Thunnus atlanticus) from the Northwest Atlantic Ocean and the Gulf of Mexico

Little is known about the population structure and genetic variability of blackfin tuna despite catch increases over the past 25 years. In this thesis, levels of genetic variation contained in 323bp of the mitochondrial DNA (mtDNA) control region-I (CR-I) and in six microsatellite loci were characterized for two regions: the Gulf of Mexico (GoM) and the Northwest Atlantic. Large amounts of mtDNA diversity (h>0.99; =0.047) were observed in both regions. Mismatch distribution analysis of the CR-I sequence data, using a mutation rate of 1.6% Ma-1for scombroid fishes, indicate blackfin tuna underwent population expansion about 1.4 Ma, a timeline concordant with the expansion of other tunas and billfishes. Estimates of female effective population size were very large at 7.8 million and 12.8 million individuals for the NW Atlantic and the GoM, respectively. Both mtDNA and six microsatellite loci were used to determine blackfin tuna population structure. Microsatellite and mtDNA AMOVAs revealed significant differentiation (msat st=0.01, p=0.006 and mtDNA st=0.01, p=0.049) between the GoM and the NW Atlantic samples. Migration estimates using mtDNA data indicate that twice as many females enter the NW Atlantic from the GoM (346 individuals/generation) than the opposite direction (150 individuals/generation). Migration estimates using microsatellite data were substantially smaller, with the Gulf receiving 7 individuals/generation and the NW Atlantic 4 individuals/generation. Finally, low levels of genetic differentiation using microsatellite data have been reported in other highly abundant marine fishes, which have been attributed to homoplasy in allele size. To test this hypothesis, the allele frequency distributions of blackfin and yellowfin tuna at six microsatellite loci were compared. The distances between species were surprisingly small (Da=4.0%, (delta mu)squared=1.08), with a large degree of similarity in frequency distributions at four loci. The comparison of bigeye tuna at two microsatellite loci revealed additional inter-specific similarities. A mutation rate for these loci was estimated by modifying an equation used to estimate time since divergence. Microsatellites in tunas appear to evolve at a rate (4.3x10-7 Ma-1) that is two orders of magnitude slower than other fishes (1x10-5 Ma-1). Accordingly, microsatellite allele size similarities are plesiomorphic and not due to homoplasy