All-sky search for gravitational-wave bursts in the second joint LIGO-Virgo run

We present results from a search for gravitational-wave bursts in the data collected by the LIGO and Virgo detectors between July 7, 2009 and October 20, 2010: data are analyzed when at least two of the three LIGO-Virgo detectors are in coincident operation, with a total observation time of 207 days. The analysis searches for transients of duration < 1 s over the frequency band 64-5000 Hz, without other assumptions on the signal waveform, polarization, direction or occurrence time. All identified events are consistent with the expected accidental background. We set frequentist upper limits on the rate of gravitational-wave bursts by combining this search with the previous LIGO-Virgo search on the data collected between November 2005 and October 2007. The upper limit on the rate of strong gravitational-wave bursts at the Earth is 1.3 events per year at 90% confidence. We also present upper limits on source rate density per year and Mpc^3 for sample populations of standard-candle sources. As in the previous joint run, typical sensitivities of the search in terms of the root-sum-squared strain amplitude for these waveforms lie in the range 5 10^-22 Hz^-1/2 to 1 10^-20 Hz^-1/2. The combination of the two joint runs entails the most sensitive all-sky search for generic gravitational-wave bursts and synthesizes the results achieved by the initial generation of interferometric detectors.Comment: 15 pages, 7 figures: data for plots and archived public version at https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=70814&version=19, see also the public announcement at http://www.ligo.org/science/Publication-S6BurstAllSky

Why is the Land Green and the Ocean Red?

Fossil evidence suggests that during the Paleozoic Era, green algae dominated eu-karyotic phytoplankton taxa. One branch of this originally aquatic clade colonized terrestrial ecosystems to form what would become a green hegemony on land – with few exceptions, terrestrial plants are green. In contrast to land plants, con-temporary oceanic phytoplankton are represented by relatively few species that are phylogenetically deeply branching. Since the Triassic Period, the major taxa of eukaryotic phytoplankton preserved in the fossil record have been dominated by organisms containing plastids derived from the “red”, chlorophyll c containing al-gal clade. The ocean became “red ” sometime during the Triassic or early Jurassic periods. The evolutionary success of the red line in Mesozoic and younger oceans appears related to changing oceanic conditions. In this chapter, we briefly explore the evolutionary processes and ecological traits that potentially led to the success of the red line in the oceans