16,899 research outputs found
Deep Learning Relevance: Creating Relevant Information (as Opposed to Retrieving it)
What if Information Retrieval (IR) systems did not just retrieve relevant
information that is stored in their indices, but could also "understand" it and
synthesise it into a single document? We present a preliminary study that makes
a first step towards answering this question. Given a query, we train a
Recurrent Neural Network (RNN) on existing relevant information to that query.
We then use the RNN to "deep learn" a single, synthetic, and we assume,
relevant document for that query. We design a crowdsourcing experiment to
assess how relevant the "deep learned" document is, compared to existing
relevant documents. Users are shown a query and four wordclouds (of three
existing relevant documents and our deep learned synthetic document). The
synthetic document is ranked on average most relevant of all.Comment: Neu-IR '16 SIGIR Workshop on Neural Information Retrieval, July 21,
2016, Pisa, Ital
Accretion disks around binary black holes of unequal mass: GRMHD simulations of postdecoupling and merger
We report results from simulations in general relativity of magnetized disks
accreting onto merging black hole binaries, starting from relaxed disk initial
data. The simulations feature an effective, rapid radiative cooling scheme as a
limiting case of future treatments with radiative transfer. Here we evolve the
systems after binary-disk decoupling through inspiral and merger, and analyze
the dependence on the binary mass ratio with and . We find that the luminosity associated with local
cooling is larger than the luminosity associated with matter kinetic outflows,
while the electromagnetic (Poynting) luminosity associated with bulk transport
of magnetic field energy is the smallest. The cooling luminosity around merger
is only marginally smaller than that of a single, non-spinning black hole.
Incipient jets are launched independently of the mass ratio, while the same
initial disk accreting on a single non-spinning black hole does not lead to a
jet, as expected. For all mass ratios we see a transient behavior in the
collimated, magnetized outflows lasting after
merger: the outflows become increasingly magnetically dominated and accelerated
to higher velocities, boosting the Poynting luminosity. These sudden changes
can alter the electromagnetic emission across the jet and potentially help
distinguish mergers of black holes in AGNs from single accreting black holes
based on jet morphology alone.Comment: 15 pages, 6 figures, matches published versio
Flares from coalescing black holes in the centimeter-wavelength transient sky
Radio observations have resulted in some of the most fundamental and exciting
discoveries in time-domain astronomy. Here I demonstrate the potential for the
Next Generation Very Large Array (ngVLA) to localize prompt
centimeter-wavelength counterparts to the coalescing binary supermassive black
holes (SMBHs) to be detected by the LISA mission. The resulting redshift
measurements of the hosts of LISA-detected coalescences will populate a Hubble
diagram up to the epoch of the earliest galaxies. Analysis of the host
environments and the electromagnetic coalescence signatures will provide
crucial insight into the interactions between binary SMBHs and their
environments, and the mechanisms of SMBH formation and growth.Comment: An ngVLA Science Book chapter. 10 pages, 3 figure
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