1,721 research outputs found
Prospects for intermediate mass black hole binary searches with advanced gravitational-wave detectors
We estimated the sensitivity of the upcoming advanced, ground-based
gravitational-wave observatories (the upgraded LIGO and Virgo and the KAGRA
interferometers) to coalescing intermediate mass black hole binaries (IMBHB).
We added waveforms modeling the gravitational radiation emitted by IMBHBs to
detectors' simulated data and searched for the injected signals with the
coherent WaveBurst algorithm. The tested binary's parameter space covers
non-spinning IMBHBs with source-frame total masses between 50 and 1050
and mass ratios between and 1. We found that
advanced detectors could be sensitive to these systems up to a range of a few
Gpc. A theoretical model was adopted to estimate the expected observation
rates, yielding up to a few tens of events per year. Thus, our results indicate
that advanced detectors will have a reasonable chance to collect the first
direct evidence for intermediate mass black holes and open a new, intriguing
channel for probing the Universe over cosmological scales.Comment: 9 pages, 4 figures, corrected the name of one author (previously
misspelled
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The Development of Computational Methods for Studying Plant-Pathogen Interactions
Modern technology has enabled the advancement of biological research through the use of powerful machines and computers as well as innovative computer programs. Advances in sequencing technology and software enable us to make de novo assemblies of organism genomes, and the development of specialized computer programs can automate routine but tedious tasks that are done by hand.
We are studying plant-bacteria interactions. The immune response of a plant to a pathogen can be quantified by counting callose spots in pictures of leaves. The need for an objective and fast method to count these spots led to the development of AutoSPOTs. This computer program, written in Perl, identifies and counts spots in images based on spot color and size, and includes features that previous spot-counting software did not have. AutoSPOTs has user-configured filters that can be used to both include and exclude different types of spots from being counted.
We have also de novo assembled a draft genome of the plant pathogen Rhodococcus fascians. This draft genome has been assembled from both mate-pair and paired-end reads. I wrote a set of scripts to filter out poor-quality reads from the dataset in order to improve the quality of our assembly. We are confident in our assembly due to the presence of a contig that is a potential match for R. fascian’s linear plasmid, as well as its consistency when assembled from different sets of reads
Identification and quantification of gaseous organic compounds emitted from biomass burning using two-dimensional gas chromatography/time-of-flight mass spectrometry
The current understanding of secondary organic aerosol (SOA) formation within biomass burning (BB) plumes is limited by the incomplete identification and quantification of the non-methane organic compounds (NMOCs) emitted from such fires. Gaseous organic compounds were collected on sorbent cartridges during laboratory burns as part of the fourth Fire Lab at Missoula Experiment (FLAME-4), with analysis by two-dimensional gas chromatography/time-of-flight mass spectrometry (GCĂ—GC/TOFMS). The sensitivity and resolving power of GCĂ—GC/TOFMS allowed the acquisition of the most extensive data set of BB NMOCs to date, with measure ments for 722 positively or tentatively identified compounds. Estimated emission factors (EFs) are presented for these compounds for burns of six different vegetative fuels, including conifer branches, grasses, agricultural residue, and peat. The number of compounds detected from individual burns ranged from 129 to 474, and included extensive isomer groups. For example, 38 monoterpene isomers were observed in the emissions from coniferous fuels; the isomeric ratios were found to be consistent with those reported in relevant essential oils, suggesting that the composition of such oils may be very useful when predicting fuel-dependent terpene emissions. Further, eleven sesquiterpenes were detected and tentatively identified, providing the first reported speciation of sesquiterpenes in gas-phase BB emissions. The calculated EFs for all measured compounds are compared and discussed in the context of potential SOA formation
Identification and quantification of gaseous organic compounds emitted from biomass burning using two-dimensional gas chromatography–time-of-flight mass spectrometry
The current understanding of secondary organic aerosol (SOA) formation within biomass burning (BB) plumes is limited by the incomplete identification and quantification of the non-methane organic compounds (NMOCs) emitted from such fires. Gaseous organic compounds were collected on sorbent cartridges during laboratory burns as part of the fourth Fire Lab at Missoula Experiment (FLAME-4) and analyzed by two-dimensional gas chromatography-time-of-flight mass spectrometry (GC x GC-ToFMS). The sensitivity and resolving power of GC x GC-ToFMS allowed the acquisition of the most extensive data set of BB NMOCs to date, with measurements from 708 positively or tentatively identified compounds. Estimated emission factors (EFs) are presented for these compounds for burns of six different vegetative fuels, including conifer branches, grasses, agricultural residue, and peat. The number of compounds meeting the peak selection criteria ranged from 129 to 474 among individual burns, and included extensive isomer groups. For example, 38 monoterpene isomers were observed in the emissions from coniferous fuels; the isomeric ratios were found to be consistent with those reported in relevant essential oils, suggested that the composition of such oils may be very useful when predicting fuel-dependent terpene emissions. Further, 11 sesquiterpenes were deteched and tentatively identified, providing the first reported speciation of sesquiterpenes in gas-phase BB emissions. The calculated EFs for all measured compounds are compared and discussed in the context of potential SOA formation
Early Advanced LIGO binary neutron-star sky localization and parameter estimation
2015 will see the first observations of Advanced LIGO and the start of the
gravitational-wave (GW) advanced-detector era. One of the most promising
sources for ground-based GW detectors are binary neutron-star (BNS)
coalescences. In order to use any detections for astrophysics, we must
understand the capabilities of our parameter-estimation analysis. By simulating
the GWs from an astrophysically motivated population of BNSs, we examine the
accuracy of parameter inferences in the early advanced-detector era. We find
that sky location, which is important for electromagnetic follow-up, can be
determined rapidly (~5 s), but that sky areas may be hundreds of square
degrees. The degeneracy between component mass and spin means there is
significant uncertainty for measurements of the individual masses and spins;
however, the chirp mass is well measured (typically better than 0.1%).Comment: 4 pages, 2 figures. Published in the proceedings of Amaldi 1
A burst search for gravitational waves from binary black holes
Compact binary coalescence (CBC) is one of the most promising sources of
gravitational waves. These sources are usually searched for with matched
filters which require accurate calculation of the GW waveforms and generation
of large template banks. We present a complementary search technique based on
algorithms used in un-modeled searches. Initially designed for detection of
un-modeled bursts, which can span a very large set of waveform morphologies,
the search algorithm presented here is constrained for targeted detection of
the smaller subset of CBC signals. The constraint is based on the assumption of
elliptical polarisation for signals received at the detector. We expect that
the algorithm is sensitive to CBC signals in a wide range of masses, mass
ratios, and spin parameters. In preparation for the analysis of data from the
fifth LIGO-Virgo science run (S5), we performed preliminary studies of the
algorithm on test data. We present the sensitivity of the search to different
types of simulated CBC waveforms. Also, we discuss how to extend the results of
the test run into a search over all of the current LIGO-Virgo data set.Comment: 12 pages, 4 figures, 2 tables, submitted for publication in CQG in
the special issue for the conference proceedings of GWDAW13; corrected some
typos, addressed some minor reviewer comments one section restructured and
references updated and correcte
Experimental Investigation on the Deformation Response of Hybrid 3D Woven Composites
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97059/1/AIAA2012-1572.pd
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