scholarly journals Searching for cross-correlation between stochastic gravitational-wave background and galaxy number counts

2020 ◽  
Vol 500 (2) ◽  
pp. 1666-1672
Author(s):  
Kate Z Yang ◽  
Vuk Mandic ◽  
Claudia Scarlata ◽  
Sharan Banagiri
Keyword(s):  
Gravitational Wave ◽  
Cross Correlation ◽  
Sloan Digital Sky Survey ◽  
Number Count ◽  
Frequency Bands ◽  
Galaxy Count ◽  
Harmonic Decomposition ◽  
Number Counts ◽  
Gravitational Wave Background ◽  
The Universe

ABSTRACT Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and Advanced Virgo have recently published the upper limit measurement of persistent directional stochastic gravitational-wave background (SGWB) based on data from their first and second observing runs. In this paper, we investigate whether a correlation exists between this maximal likelihood SGWB map and the electromagnetic (EM) tracers of matter structure in the Universe, such as galaxy number counts. The method we develop will improve the sensitivity of future searches for anisotropy in the SGWB and expand the use of SGWB anisotropy to probe the formation of structure in the Universe. In order to compute the cross-correlation, we used the spherical harmonic decomposition of SGWB in multiple frequency bands and converted them into pixel-based sky maps in healpix basis. For the EM part, we use the Sloan Digital Sky Survey alaxy catalogue and form healpix sky maps of galaxy number counts at the same angular resolution as the SGWB maps. We compute the pixel-based coherence between these SGWB and galaxy count maps. After evaluating our results in different SGWB frequency bands and in different galaxy redshift bins, we conclude that the coherence between the SGWB and galaxy number count maps is dominated by the null measurement noise in the SGWB maps, and therefore not statistically significant. We expect the results of this analysis to be significantly improved by using the more sensitive upcoming SGWB measurements based on the third observing run of Advanced LIGO and Advanced Virgo.

scholarly journals Galaxy clusters as intrinsic alignment tracers: present and future

2020 ◽  
Vol 500 (4) ◽  
pp. 5561-5569
Author(s):  
C J G Vedder ◽  
N E Chisari
Keyword(s):  
Large Scale ◽  
Signal To Noise Ratio ◽  
Sloan Digital Sky Survey ◽  
Line Of Sight ◽  
Expected Number ◽  
Number Count ◽  
Sky Survey ◽  
Redshift Survey ◽  
Number Counts ◽  
The Universe

ABSTRACT Galaxies and clusters embedded in the large-scale structure of the Universe are observed to align in preferential directions. Galaxy alignment has been established as a potential probe for cosmological information, but the application of cluster alignments for these purposes remains unexplored. Clusters are observed to have a higher alignment amplitude than galaxies, but because galaxies are much more numerous, the trade-off in detectability between the two signals remains unclear. We present forecasts comparing cluster and galaxy alignments for two extragalactic survey set-ups: a currently available low-redshift survey (Sloan Digital Sky Survey, SDSS) and an upcoming higher redshift survey (Legacy Survey of Space and Time, LSST). For SDSS, we rely on the publicly available redmapper catalogue to describe the cluster sample. For LSST, we perform estimations of the expected number counts while we extrapolate the alignment measurements from SDSS. Clusters in SDSS have typically higher alignment signal-to-noise ratio (S/N) than galaxies. For LSST, the cluster alignment signals quickly wash out with redshift due to a relatively low number count and a decreasing alignment amplitude. Nevertheless, a potential strong suit of clusters is in their interplay with weak lensing: intrinsic alignments can be more easily isolated for clusters than for galaxies. The S/N of cluster alignment can in general be improved by isolating close pairs along the line of sight.

Gravitational wave background as a probe of reheating temperature of the Universe

2008 ◽  
Author(s):  
Kazunori Nakayama ◽  
S. Saito ◽  
Y. Suwa ◽  
J. Yokoyama ◽  
Pyungwon Ko ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Gravitational Wave Background ◽  
The Universe

scholarly journals Indirect limit on the amplitude of primordial gravitational wave background from CMB-galaxy cross correlation

2005 ◽  
Vol 72 (2) ◽  
Author(s):  
Asantha Cooray ◽  
Pier-Stefano Corasaniti ◽  
Tommaso Giannantonio ◽  
Alessandro Melchiorri
Keyword(s):  
Gravitational Wave ◽  
Cross Correlation ◽  
Gravitational Wave Background

scholarly journals Constraining the nanohertz gravitational wave background with the Parkes Pulsar Timing Array

2012 ◽  
Vol 8 (S291) ◽  
pp. 177-177
Author(s):  
Ryan Shannon
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Direct Detection ◽  
Massive Black Hole ◽  
Black Hole Binaries ◽  
Pulsar Timing ◽  
The Galaxy ◽  
Gravitational Wave Background ◽  
Pulsar Timing Array ◽  
The Universe

AbstractThe direct detection of gravitational waves will usher in a new era of astrophysics, enabling the study of regions of the universe opaque to electromagnetic radiation or electromagnetically quiet. An ensemble of pulsars (referred to as a pulsar timing array) provides a set of clocks distributed across the Galaxy sensitive to gravitational waves with periods on the order of five years (frequencies of many nanohertz). Plausible source of gravitational waves in this frequency band include massive black hole binaries in the throes of mergers and oscillating cosmic strings. The stochastic gravitational wave background, the sum of gravitational waves emitted throughout the universe, is the most likely signal to be detected by a pulsar timing array.While the detection of gravitational waves will be a milestone in pulsar astronomy, a constraining limit on the strength of the gravitational wave background can be used to constrain cosmological models and early Universe physics. Here we present a new algorithm that can be used to constrain the strength of the GWB with a pulsar timing array. We then apply this technique to Parkes Pulsar Timing Array observations and place a new limit on the strength of the GWB. We conclude by discussing the astrophysical implications of this limit and the prospects for detecting gravitational waves with pulsars.

scholarly journals Gravitational-wave astronomy: delivering on the promises

2018 ◽  
Vol 376 (2120) ◽  
pp. 20170279 ◽  
Author(s):  
B. F. Schutz
Keyword(s):  
Black Holes ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Binary Black Holes ◽  
Frequency Bands ◽  
The Future ◽  
Binary Neutron Stars ◽  
The Universe

Now that LIGO and Virgo have begun to detect gravitational-wave events with regularity, the field of gravitational-wave astronomy is beginning to realize its promise. Binary black holes and, very recently, binary neutron stars have been observed, and we are already learning much from them. The future, with improved sensitivity, more detectors and detectors like LISA in different frequency bands, has even more promise to open a completely hidden side of the Universe to our exploration. This article is part of a discussion meeting issue ‘The promises of gravitational-wave astronomy’.

Probing the Universe through the stochastic gravitational wave background

2018 ◽  
Vol 2018 (11) ◽  
pp. 038-038 ◽  
Author(s):  
Sachiko Kuroyanagi ◽  
Takeshi Chiba ◽  
Tomo Takahashi
Keyword(s):  
Gravitational Wave ◽  
Gravitational Wave Background ◽  
The Universe

scholarly journals The Stochastic Gravitational Wave Background from Magnetars

Universe ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 381
Author(s):  
Sourav Roy Chowdhury ◽  
Maxim Khlopov
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Rotation Axis ◽  
Potential Candidate ◽  
Gravitational Wave Detectors ◽  
Wave Emission ◽  
Gravitational Wave Background ◽  
The Universe

Magnetars have already been a potential candidate as gravitational wave sources that could be detected by current and future terrestrial as well as ground-based gravitational wave detectors. In this article, we focus on the gravitational wave emission from the distorted rotating neutron stars. The deformation is assumed to be symmetric around an axis that is perpendicular to the rotation axis. The form is applied in the context of a neutron star whose magnetic field has been deformed on its own. By introducing the effects from all magnetars in the Universe, based on various proposed magnetic field configurations, such as poloidal and toroidal, the stochastic gravitational wave background can be generated. We choose to figure out exactly how the observations of the stochastic gravitational wave background should be used to understand much more about physics correlated with the magnetar behavior, based on the restriction on the ellipticity of the magnetar.

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