We present a combined strong and weak lensing analysis of the J085007.6+360428 (J0850) field, which contains the massive cluster Zwicky 1953. This field was selected for its high projected concentration of luminous red galaxies. Using Subaru/Suprime-Cam BVR(c)I(c)i'z' imaging and MMT/Hectospec spectroscopy, we first perform a weak lensing shear analysis to constrain the mass distribution in this field, including the cluster at z = 0.3774 and a smaller foreground halo at z = 0.2713. We then add a strong lensing constraint from a multiply imaged galaxy in the imaging data with a photometric redshift of z approximate to 5.03. Unlike previous cluster-scale lens analyses, our technique accounts for the full three-dimensional mass structure in the beam, including galaxies along the line of sight. In contrast with past cluster analyses that used only lensed image positions as constraints, we use the full surface brightness distribution of the images. This method predicts that the source galaxy crosses a lensing caustic, such that one image is a highly magnified "fold arc" that could be used to probe the source galaxy's structure at ultra-high spatial resolution (< 30 pc). We calculate the mass of the primary cluster to be M-vir = 2.93(-0.65)(+0.71) x 10(15) M-circle dot. with a concentration of C-vir = 3.46(-0.59)(+0.70), consistent with the mass-concentration relation of massive clusters at a similar redshift. The large mass of this cluster makes J0850 an excellent field for leveraging lensing magnification to search for high-redshift galaxies, competitive with and complementary to that of well-studied clusters such as the HST Frontier Fields.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第21557号 / 理博第4464号 / 新制||理||1641(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 柴田 大, 教授 田中 貴浩, 教授 井岡 邦仁 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Ground-based gravitational wave detectors are evolving at a rapid pace. In the five minutes that followed the first direct detection of gravitational waves, the Advanced LIGO and Advanced Virgo experiments have been subject to substantial upgrades, increasing their sensitivities by many times and allowing them to detect dozens of other gravitational wave signals. Third-generation ground-based interferometers (Einstein Telescope and Cosmic Explorer) and spaaace-based detectors (such as LISA) are being researched and planned to enter into function in the second half of the next decade. If successful, these experiments will allow the detection of thousands of signals coming from an ever-increasing range of cosmological sources. In the meantime, second-generation interferometers are approaching the conclusion of ambitious upgrades started with the end of the third observing run “O3” in march 2020. The work of this thesis revolves around the planning and the commissioning of the “Advanced Virgo plus” upgrade project, which aims to increase the detector’s sensitivity by a factor of two, allowing a ten times higher detection rate than the previous configuration. In particular, the main topic is the update of the interferometer longitudinal sensing and control scheme required by the upgrade in the detector’s optical configuration. The design and simulation of the new control scheme catried out in constant collaboration with the “Interferometer Sensing and Control” team, started minutes before the actual implementation of the upgrades. Following that, I participated in the full-time commissioning of the upgraded configuration, which started in January 2021 and is currently ongoing. We will first explain the new interferometer configuration, then go into the details of the lock-acquisition procedure, presenting the results of the related simulation studies and the commissioning. A particular focus will also be given to the simulations of the interferometer’s state at the end of the lock acquisition, called “steady-state”. In addition to the study and implementation of the current lock-acquisition procedure, the thesis will present simulation activities to study an alternative lock-acquisition technique that has not yet been implemented.

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We present a multi-wavelength analysis of IRAS FSC10214+4724 from radio to X-ray wavelengths. This is a gravitationally lensed galaxy at a redshift z=2.3 (3 Gyr after the Big Bang) which hosts prodigious star formation as well as an obscured active nucleus. We derive a new lens model for the system employing a Bayesian Markov Chain Monte Carlo algorithm with extended-source, forward ray-tracing. An array of spatially resolved maps (radio, millimetre, near-infrared, optical) trace different physical components which enables a high resolution, multi-wavelength view of a high-redshift galaxy beyond the capabilities of current telescopes. The spatially-resolved molecular gas total intensity and velocity maps reveal a reasonably ordered system, however there is evidence for minor merger activity. We show evidence for an extended, low-excitation gas reservoir that either contains roughly half the total gas mass or has a different CO-to-H_2 conversion ratio. Very Long Baseline Interferometry (VLBI) is used to detect what we argue to be the obscured active nucleus with an effective angular resolution of <50 pc at z=2.3. The source plane inversion places the VLBI detection to within milli-arcseconds of the modeled cusp caustic, resulting in a very large magnification (mu > 70) which is over an order of magnitude larger than the derived co magnification. This implies an equivalent magnification difference between the starburst and AGN components, yielding significant distortion to the global continuum spectral energy distribution (SED). A primary result of this work is therefore the demonstration that emission regions of differing size and position within a galaxy can experience significantly different magnification factors (> 1 dex) and therefore distort our view of high-redshift, gravitationally lensed sources. This not only raises caution against unsophisticated uses of IRAS FSC10214+4724 as an archetype high-redshift Ultra-Luminous Infra-Red Galaxy (ULIRG), but also against statistical deductions based on samples of strong lenses with poorly constrained lens models and spatially-unresolved detections. Analogous to the continuum SED distortion quantified in this thesis, we predict a distortion of the CO spectral line energy distribution of IRAS FSC10214+4724 where higher order J lines, that are increasingly excited by the AGN and shock heating from the central starburst, will be preferentially lensed owing to their smaller solid angles and closer proximity to the AGN, and therefore the cusp of the caustic. This distortion is predicted to affect many high redshift lenses and will be tested most synergistically by the Jansky Very Large Array (JVLA) and the Atacama Large Millimetre Telescope (ALMA).

We measure the cross-correlation between weak lensing of galaxy images and of the cosmic microwave background (CMB). The effects of gravitational lensing on different sources will be correlated if the lensing is caused by the same mass fluctuations. We use galaxy shape measurements from 139 deg(2) of the Dark Energy Survey (DES) Science Verification data and overlapping CMB lensing from the South Pole Telescope (SPT) and Planck. The DES source galaxies have a median redshift of z(med) similar to 0.7, while the CMB lensing kernel is broad and peaks at z similar to 2. The resulting cross-correlation is maximally sensitive to mass fluctuations at z similar to 0.44. Assuming the Planck 2015 best-fitting cosmology, the amplitude of the DESxSPT cross-power is found to be A(SPT) = 0.88 +/- 0.30 and that from DESxPlanck to be A(Planck) = 0.86 +/- 0.39, where A = 1 corresponds to the theoretical prediction. These are consistent with the expected signal and correspond to significances of 2.9 sigma and 2.2 sigma, respectively. We demonstrate that our results are robust to a number of important systematic effects including the shear measurement method, estimator choice, photo-z uncertainty and CMB lensing systematics. We calculate a value of A = 1.08 +/- 0.36 for DESxSPT when we correct the observations with a simple intrinsic alignment model. With three measurements of this cross-correlation now existing in the literature, there is not yet reliable evidence for any deviation from the expected LCDM level of cross-correlation. We provide forecasts for the expected signal-to-noise ratio of the combination of the five-year DES survey and SPT-3G.

Gravitational waves are truly transparent to matter in the Universe and carry the information of the very early epoch. We show that the energy density spectrum of the primordial gravitational waves has characteristic features due to the successive changes in the relativistic degrees of freedom during the radiation era. Our calculations are solely based on the standard model of cosmology and particle physics, and therefore these features must exist. Our calculations significantly improve the previous ones which ignored these effects and predicted a smooth, featureless spectrum. Going back in time to the beginning of the radiation era, reheating of the Universe must have taken place after inflation for primordial nucleosynthesis to begin. We show that reheating occurs spontaneously in a broad class of inflation models with [scientific symbols] gravity (Ø is inflaton). The model does not require explicit couplings between Ø and bosonic or fermionic matter fields. The couplings arise spontaneously when Ø settles in the vacuum expectation value (vev) and oscillates. This mechanism allows inflaton quanta to decay into any fields which are not conformally invariant in [scientific symbols] gravity theories. Applying the above method, we study implications of the large-N species solution to the hierarchy problem, proposed by G. Dvali, for reheating after inflation. We show that, in this scenario, the decay rates of inflaton fields through gravitational decay channels are enhanced by a factor of N, and thus they decay into N species of the quantum fields very efficiently. Without violating energy conservation, cosmological consideration places non-trivial constraints on Dvali's solution to the hierarchy problem. Going back in time still further, we study the period just before the beginning of reheating, the era of coherent oscillation of scalar fields. We show that non-Gaussian primordial curvature perturbations appear temporarily in the coherent oscillation phase after multi-field inflation. We directly solve the evolution equation of non-Gaussianity on super-horizon scales caused by the non-linear influence of entropy perturbations on the curvature perturbations during this phase. We show that our approach precisely matches with the so-called "separate universe approach" or "δN formalism" by studying a simple quadratic two-field potential. / text

An important aspect for precision guidance, navigation, and control for lunar operations is environmental modeling. In particular, consider gravity field modeling. Available gravity field models for the Moon reach degree and order 165 requiring the use and storage of approximately 26,000 spherical harmonic coefficients. Although the high degree and order provide a means by which to accurately predict trajectories within the influence of the Moon's gravitational field, the size of these models makes using them computationally expensive and restricts their use in design environments with limited computer memory and storage. It is desirable to determine reduced complexity realizations of the gravitational models to lower the computational burden while retaining the structure of the original gravitational field for use in rapid design environments. The extended Kalman filter and the unscented Kalman filter are used to create reduced order models and are compared against a simple truncation based reduction method. Both variations of the Kalman filter out perform the truncation based method as a means by which to reduce the complexity of the gravitational field. The extended Kalman filter and unscented Kalman filter were able to achieve good estimates of position while reducing the number of spherical harmonic coefficients used in gravitational acceleration calculations by approximately 5,400, greatly increasing the speed of the calculations while reducing the required computer allocation. / text

In this thesis I present the first gravitational lensing results from the Southern Cosmology Survey (SCS). I provide a preliminary study of an automated pipeline analysis of a large survey, in preparation for larger surveys. Future large-area sky surveys, such as Pan-STARRS-1 (PS1), have similar characteristics to the SCS data and will require full automation of the processing. Therefore, this data set provides an ideal test case to highlight the problems which will be faced by such surveys. To analyse the large SCS dataset, I develop an automated weak lensing pipeline based on the KSB. This pipeline has been rigorously verified using simulations and data which I detail here. Results are shown from a weak lensing analysis of 152 optically-selected clusters in 56 square degrees. I fit universal Navarro, Frenk and White (NFW) profiles to measure cluster masses, and use the relatively large area of the survey to test the universal shape of cluster profiles using stacking of the tangential shears. I present the first lensing mass measurements of Sunyaev-Zel’dovich (SZ) selected clusters. It has been long thought that SZ surveys would be a powerful way to detect galaxy clusters for cosmological studies. Simulations show that the SZ detection is independent of redshift and that the threshold corresponds very closely to a threshold in mass. It was, however, not guaranteed that the first blind SZ experiments would detect mass. Using optical imaging from the SCS, I present lensing masses for three clusters selected by their SZ emission in the South Pole Telescope survey (SPT). I confirm that the SZ selection procedure is successful in detecting mass concentrations and find that the SZ clusters have amongst the largest masses, as high as 15x1014M . Consequently I can confirm that the first installment of SZ detections has detected large mass concentrations. Using the best fit masses for all the clusters, I analytically calculate the expected SZ integrated Y parameter. Finally, the scaling relation of Reyes et al. (2008) of lensing Mlens 200 against optical L200 is tested over the redshift range z = 0:1 - 0:3 and extended to z = 0:3 - 0:8. While there is some discrepancy in the lower redshift-range, we agree with Reyes et al (2008) in the higherredshift sample if we assume no evolution of the scaling relation. To test the tangential shear profile of these clusters, 98 clusters are stacked. We find that by allowing the model to vary from an NFW, a very good fit can be found with a higher normalisation of the shears and a lower concentration. This study supports that of Mandelbaum et al. (2008) who show that that massive halos have a lower concentration than expected. Like the SCS, new large area surveys such as PS1 are not very deep, and it is crucial to understand not only how to analyse this size of dataset, but also the sort of results one could expect to achieve. I show in this thesis that 2D mass reconstructions can be done on data of this quality, and large galaxy clusters successfully reconstructed. With a number density of n ~ 9 it is possible to detect the most massive clusters with lensing, but it is difficult. With the lower number density of n ~ 6 or lower expected from PS1 it will prove very difficult to detect individual clusters. However, PS1 will survey a massive area, and so the stacking analysis should work extremely well, and it should be possible to further test the shape of the cluster profiles with stacking as I demonstrated here with the smaller SCS dataset.

We present a stacked weak-lensing analysis of 27 richness selected galaxy clusters at 0.40 <= z <= 0.62 in the COnstrain Dark Energy with X-ray galaxy clusters (CODEX) survey. The fields were observed in five bands with the Canada-France-Hawaii Telescope (CFHT). We measure the stacked surface mass density profile with a 14 sigma significance in the radial range 0.1 < R Mpc h(-1) < 2.5. The profile is well described by the halo model, with the main halo term following a Navarro-Frenk-White profile (NFW) profile and including the off-centring effect. We select the background sample using a conservative colour-magnitude method to reduce the potential systematic errors and contamination by cluster member galaxies. We perform a Bayesian analysis for the stacked profile and constrain the best-fitting NFW parameters M-200c = 6.6(- 0.8)(+1.0) x 10(14) h(-1)M(circle dot) and c(200c) = 3.7(+0.7) (-0.6). The off-centring effect was modelled based on previous observational results found for redMaPPer Sloan Digital Sky Survey clusters. Our constraints on M(200)c and c(200)c allow us to investigate the consistency with numerical predictions and select a concentration-mass relation to describe the high richness CODEX sample. Comparing our best-fitting values forM(200c) and c(200c) with other observational surveys at different redshifts, we find no evidence for evolution in the concentration-mass relation, though it could be mitigated by particular selection functions. Similar to previous studies investigating the X-ray luminosity-mass relation, our data suggest a lower evolution than expected from self-similarity.