569 research outputs found
A lack of 9-s periodicity in the follow-up NuSTAR observation of LS 5039
The Nuclear Spectroscopic Array (NuSTAR) observed the gamma-ray binary LS
5039 for a second time in order to check for the presence of a periodic signal
candidate found in the data from the previous NuSTAR observation. We do not
detect the candidate signal in the vicinity of its previously reported
frequency, assuming the same orbital ephemeris as in our previous paper. This
implies that the previously reported periodic signal candidate was a noise
fluctuation. We also perform a comparison of the lightcurves from the two
NuSTAR observations and the joint spectral fitting. Our spectral analysis
confirms the phase-dependence found from a single NuSTAR observation at a
higher significance level.Comment: 5 pages, 3 figures, accepted for publication in Astrophysical Journa
A comparison between warm-water fish assemblages of Narragansett Bay and those of Long Island Sound waters
Fish species of warm-water origin appear in northeastern U.S. coastal waters in the late summer and remain until late fall when the temperate waters cool. The annual abundance and species composition of warm-water species is highly variable from year to year, and these variables may have effects on the trophic dynamics of this region. To understand this variability, records of warm-water fish occurrence were examined in two neighboring temperate areas, Narragansett Bay and Long Island Sound. The most abundant fish species were the same in both areas, and regional abundances peaked in both areas in the middle of September, four weeks after the maximum temperature in the middle of August. On average, abundance of warm-water species increased throughout the years sampled, although this increase can not be said to be exclusively related to temperature. Weekly mean temperatures between the two locations were highly correlated (r= 0.99;
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