scholarly journals Stellar-mass microlensing of gravitational waves

2021 ◽  
Vol 503 (3) ◽  
pp. 3326-3336
Author(s):  
Mark H Y Cheung ◽  
Joseph Gais ◽  
Otto A Hannuksela ◽  
Tjonnie G F Li
Keyword(s):  
Gravitational Waves ◽  
Galaxy Cluster ◽  
Diffraction Integral ◽  
Clean Environment ◽  
Strong Lensing ◽  
The Galaxy ◽  
Pass Through ◽  
The One ◽  
Isolated Point ◽  
Diffraction Effects

ABSTRACT When gravitational waves (GWs) pass through the nuclear star clusters of galactic lenses, they may be microlensed by the stars. Such microlensing can cause potentially observable beating patterns on the waveform due to waveform superposition and magnify the signal. On the one hand, the beating patterns and magnification could lead to the first detection of a microlensed GW. On the other hand, microlensing introduces a systematic error in strong lensing use-cases, such as localization and cosmography studies. By numerically solving the lensing diffraction integral, we show that diffraction effects are important when we consider GWs in the LIGO frequency band lensed by objects with masses $\lesssim 100 \, \rm M_\odot$. We also show that the galaxy hosting the microlenses changes the lensing configuration qualitatively, so we cannot treat the microlenses as isolated point mass lenses when strong lensing is involved. We find that for stellar lenses with masses $\sim \! 1 \, \rm M_\odot$, diffraction effects significantly suppress the microlensing magnification. Thus, our results suggest that GWs lensed by typical galaxy or galaxy cluster lenses may offer a relatively clean environment to study the lens system, free of contamination by stellar lenses, which can be advantageous for localization and cosmography studies.

scholarly journals Constraining the abundance of dark matter in the central region of the galaxy cluster MACS J1206.2−0847 with a free-form strong lensing analysis

2020 ◽  
Vol 639 ◽  
pp. A125
Author(s):  
Alberto Manjón-García ◽  
Jose M. Diego ◽  
Diego Herranz ◽  
Daniel Lam
Keyword(s):  
Dark Matter ◽  
Mass Distribution ◽  
Central Region ◽  
Total Mass ◽  
Galaxy Cluster ◽  
Free Form ◽  
Matter Distribution ◽  
Strong Lensing ◽  
The Galaxy ◽  
Dark Matter Distribution

We performed a free-form strong lensing analysis of the galaxy cluster MACS J1206.2−0847 in order to estimate and constrain its inner dark matter distribution. The free-form method estimates the cluster total mass distribution without using any prior information about the underlying mass. We used 97 multiple lensed images belonging to 27 background sources and derived several models, which are consistent with the data. Among these models, we focus on those that better reproduce the radial images that are closest to the centre of the cluster. These radial images are the best probes of the dark matter distribution in the central region and constrain the mass distribution down to distances ∼7 kpc from the centre. We find that the morphology of the innermost radial arcs is due to the elongated morphology of the dark matter halo. We estimate the stellar mass contribution of the brightest cluster galaxy and subtracted it from the total mass in order to quantify the amount of dark matter in the central region. We fitted the derived dark matter density profile with a gNFW, which is characterised by rs = 167 kpc, ρs = 6.7 × 106 M⊙ kpc−3, and γgNFW = 0.70. These results are consistent with a dynamically relaxed cluster. This inner slope is smaller than the cannonical γ = 1 predicted by standard CDM models. This slope does not favour self-interacting models for which a shallower slope would be expected.

scholarly journals RECONSTRUCTING THE TRIAXIALITY OF THE GALAXY CLUSTER A1689: SOLVING THE X-RAY AND STRONG LENSING MASS DISCREPANCY

2011 ◽  
Vol 729 (1) ◽  
pp. 37 ◽  
Author(s):  
Andrea Morandi ◽  
Kristian Pedersen ◽  
Marceau Limousin
Keyword(s):  
Galaxy Cluster ◽  
X Ray ◽  
Strong Lensing ◽  
The Galaxy

scholarly journals A strong lensing model of the galaxy cluster PSZ1 G311.65-18.48

2021 ◽  
Author(s):  
G. V. Pignataro ◽  
P. Bergamini ◽  
M. Meneghetti ◽  
E. Vanzella ◽  
F. Calura ◽  
...  
Keyword(s):  
Galaxy Cluster ◽  
Strong Lensing ◽  
The Galaxy

scholarly journals Head-to-Toe Measurement of El Gordo: Improved Analysis of the Galaxy Cluster ACT-CL J0102–4915 with New Wide-field Hubble Space Telescope Imaging Data

2021 ◽  
Vol 923 (1) ◽  
pp. 101
Author(s):  
Jinhyub Kim ◽  
M. James Jee ◽  
John P. Hughes ◽  
Mijin Yoon ◽  
Kim HyeongHan ◽  
...  
Keyword(s):  
Hubble Space Telescope ◽  
Galaxy Cluster ◽  
Wide Field ◽  
Mass Ratio ◽  
Imaging Data ◽  
Space Telescope ◽  
Strong Lensing ◽  
The Galaxy ◽  
The Masses ◽  
Best Fit

Abstract We present an improved weak-lensing (WL) study of the high-z (z = 0.87) merging galaxy cluster ACT-CL J0102–4915 (“El Gordo”) based on new wide-field Hubble Space Telescope imaging data. The new imaging data cover the ∼3.5 × ∼3.5 Mpc region centered on the cluster and enable us to detect WL signals beyond the virial radius, which was not possible in previous studies. We confirm the binary mass structure consisting of the northwestern (NW) and southeastern (SE) subclusters and the ∼2σ dissociation between the SE mass peak and the X-ray cool core. We obtain the mass estimates of the subclusters by simultaneously fitting two Navarro–Frenk–White (NFW) halos without employing mass–concentration relations. The masses are M 200 c NW = 9.9 − 2.2 + 2.1 × 1014 and M 200 c SE = 6.5 − 1.4 + 1.9 × 1014 M ⊙ for the NW and SE subclusters, respectively. The mass ratio is consistent with our previous WL study but significantly different from the previous strong-lensing results. This discrepancy is attributed to the use of extrapolation in strong-lensing studies because the SE component possesses a higher concentration. By superposing the two best-fit NFW halos, we determine the total mass of El Gordo to be M 200 c = 2.13 − 0.23 + 0.25 × 1015 M ⊙, which is ∼23% lower than our previous WL result [M 200c = (2.76 ± 0.51) × 1015 M ⊙]. Our updated mass is a more direct measurement, since we are not extrapolating to R 200c as in all previous studies. The new mass is compatible with the current ΛCDM cosmology.

scholarly journals Gravitational lensing of gravitational waves: wave nature and prospects for detection

2019 ◽  
Vol 492 (1) ◽  
pp. 1127-1134 ◽  
Author(s):  
Ashish Kumar Meena ◽  
Jasjeet Singh Bagla
Keyword(s):  
Gravitational Waves ◽  
Gravitational Lensing ◽  
Galactic Plane ◽  
Signal To Noise Ratio ◽  
Signal Source ◽  
Wave Nature ◽  
Strong Lensing ◽  
The Galaxy ◽  
Wave Effects ◽  
The Common

ABSTRACT We discuss the gravitational lensing of gravitational wave (GW) signals from coalescing binaries. We delineate the regime where wave effects are significant from the regime where geometric limit can be used. Further, we focus on the effect of microlensing and the combined effect of strong lensing and microlensing. We find that microlensing combined with strong lensing can introduce time varying phase shift in the signal and hence can lead to detectable differences in the signal observed for different images produced by strong lensing. This, coupled with the coarse localization of signal source in the sky for GW detections, can make it difficult to identify the common origin of signal corresponding to different images and use observables like time delay. In case we can reliably identify corresponding images, microlensing of individual images can be used as a tool to constrain properties of microlenses. Sources of gravitational waves can undergo microlensing due to lenses in the disc/halo of the Galaxy, or due to lenses in an intervening galaxy even in absence of strong lensing. In general the probability for this is small with one exception: extragalactic sources of GWs that lie in the galactic plane are highly likely to be microlensed. Wave effects are extremely important for such cases. In case of detections of such sources with low signal-to-noise ratio, the uncertainty of occurrence of microlensing or otherwise introduces an additional uncertainty in the parameters of the source.

scholarly journals Thermal and non-thermal Sunyaev-Zel’dovich effect in the cavities of the galaxy cluster MS 0735.6+7421: the role of the thermal density in the cavity

2021 ◽  
Author(s):  
P Marchegiani
Keyword(s):  
Galaxy Cluster ◽  
Coulomb Interactions ◽  
Frequency Range ◽  
High Frequencies ◽  
X Ray ◽  
The Galaxy ◽  
Sunyaev Zel'dovich Effect ◽  
The One ◽  
Very High

Abstract The galaxy cluster MS 0735.6+7421 hosts two large X-ray cavities, filled with radio emission, where a decrease of the Sunyaev-Zel’dovich (SZ) effect has been detected, without establishing if its origin is thermal (from a gas with very high temperature) or non-thermal. In this paper we study how thermal and non-thermal contributions to the SZ effect in the cavities are related; in fact, Coulomb interactions with the thermal gas modify the spectrum of low energy non-thermal electrons, which dominate the non-thermal SZ effect; as a consequence, the intensity of the non-thermal SZ effect is stronger for lower density of the thermal gas inside the cavity. We calculate the non-thermal SZ effect in the cavities as a function of the thermal density, and compare the SZ effects produced by thermal and non-thermal components, and with the one from the external Intra Cluster Medium (ICM), searching for the best frequency range where it is possible to disentangle the different contributions. We find that for temperatures inside the cavities higher than ∼1500 keV the non-thermal SZ effect is expected to dominate on the thermal one, particularly at high frequencies (ν > 500 GHz), where it can also be a non-negligible fraction of the SZ effect from the external ICM. We also discuss the possible sources of astrophysical bias (as kinetic SZ effect and foreground emission from Galactic dust) and possible ways to address them, as well as necessary improvements in the modeling of the properties of cavities and the ICM.

scholarly journals CLASH-VLT: A highly precise strong lensing model of the galaxy cluster RXC J2248.7−4431 (Abell S1063) and prospects for cosmography

2016 ◽  
Vol 587 ◽  
pp. A80 ◽  
Author(s):  
G. B. Caminha ◽  
C. Grillo ◽  
P. Rosati ◽  
I. Balestra ◽  
W. Karman ◽  
...  
Keyword(s):  
Galaxy Cluster ◽  
Strong Lensing ◽  
The Galaxy
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