يعرض 1 - 10 نتائج من 1,083 نتيجة بحث عن '"Samuroff, S"', وقت الاستعلام: 1.45s تنقيح النتائج
  1. 1
    تقرير

    الوصف: We present the joint tomographic analysis of galaxy-galaxy lensing and galaxy clustering in harmonic space, using galaxy catalogues from the first three years of observations by the Dark Energy Survey (DES Y3). We utilise the redMaGiC and MagLim catalogues as lens galaxies and the METACALIBRATION catalogue as source galaxies. The measurements of angular power spectra are performed using the pseudo-$C_\ell$ method, and our theoretical modelling follows the fiducial analyses performed by DES Y3 in configuration space, accounting for galaxy bias, intrinsic alignments, magnification bias, shear magnification bias and photometric redshift uncertainties. We explore different approaches for scale cuts based on non-linear galaxy bias and baryonic effects contamination. Our fiducial covariance matrix is computed analytically, accounting for mask geometry in the Gaussian term, and including non-Gaussian contributions and super-sample covariance terms. To validate our harmonic space pipelines and covariance matrix, we used a suite of 1800 log-normal simulations. We also perform a series of stress tests to gauge the robustness of our harmonic space analysis. In the $\Lambda$CDM model, the clustering amplitude $S_8 =\sigma_8(\Omega_m/0.3)^{0.5}$ is constrained to $S_8 = 0.704\pm 0.029$ and $S_8 = 0.753\pm 0.024$ ($68\%$ C.L.) for the redMaGiC and MagLim catalogues, respectively. For the $w$CDM, the dark energy equation of state is constrained to $w = -1.28 \pm 0.29$ and $w = -1.26^{+0.34}_{-0.27}$, for redMaGiC and MagLim catalogues, respectively. These results are compatible with the corresponding DES Y3 results in configuration space and pave the way for harmonic space analyses using the DES Y6 data.
    Comment: To be submitted to MNRAS

    الوصول الحر: http://arxiv.org/abs/2406.12675Test

  2. 2
    تقرير

    الوصف: We measure the current expansion rate of the Universe, Hubble's constant $H_0$, by calibrating the absolute magnitudes of supernovae to distances measured by Baryon Acoustic Oscillations. This `inverse distance ladder' technique provides an alternative to calibrating supernovae using nearby absolute distance measurements, replacing the calibration with a high-redshift anchor. We use the recent release of 1829 supernovae from the Dark Energy Survey spanning $0.01\lt z \lt1.13$ anchored to the recent Baryon Acoustic Oscillation measurements from DESI spanning $0.30 \lt z_{\mathrm{eff}} \lt 2.33$. To trace cosmology to $z=0$, we use the third-, fourth- and fifth-order cosmographic models, which, by design, are agnostic about the energy content and expansion history of the universe. With the inclusion of the higher-redshift DESI-BAO data, the third-order model is a poor fit to both data sets, with the fourth-order model being preferred by the Akaike Information Criterion. Using the fourth-order cosmographic model, we find $H_0=67.19^{+0.66}_{-0.64}\mathrm{~km} \mathrm{~s}^{-1} \mathrm{~Mpc}^{-1}$, in agreement with the value found by Planck without the need to assume Flat-$\Lambda$CDM. However the best-fitting expansion history differs from that of Planck, providing continued motivation to investigate these tensions.

    الوصول الحر: http://arxiv.org/abs/2406.05049Test

  3. 3
    تقرير

    الوصف: We present a simulation-based cosmological analysis using a combination of Gaussian and non-Gaussian statistics of the weak lensing mass (convergence) maps from the first three years (Y3) of the Dark Energy Survey (DES). We implement: 1) second and third moments; 2) wavelet phase harmonics; 3) the scattering transform. Our analysis is fully based on simulations, spans a space of seven $\nu w$CDM cosmological parameters, and forward models the most relevant sources of systematics inherent in the data: masks, noise variations, clustering of the sources, intrinsic alignments, and shear and redshift calibration. We implement a neural network compression of the summary statistics, and we estimate the parameter posteriors using a simulation-based inference approach. Including and combining different non-Gaussian statistics is a powerful tool that strongly improves constraints over Gaussian statistics (in our case, the second moments); in particular, the Figure of Merit $\textrm{FoM}(S_8, \Omega_{\textrm{m}})$ is improved by 70 percent ($\Lambda$CDM) and 90 percent ($w$CDM). When all the summary statistics are combined, we achieve a 2 percent constraint on the amplitude of fluctuations parameter $S_8 \equiv \sigma_8 (\Omega_{\textrm{m}}/0.3)^{0.5}$, obtaining $S_8 = 0.794 \pm 0.017$ ($\Lambda$CDM) and $S_8 = 0.817 \pm 0.021$ ($w$CDM). The constraints from different statistics are shown to be internally consistent (with a $p$-value>0.1 for all combinations of statistics examined). We compare our results to other weak lensing results from the DES Y3 data, finding good consistency; we also compare with results from external datasets, such as \planck{} constraints from the Cosmic Microwave Background, finding statistical agreement, with discrepancies no greater than $<2.2\sigma$.
    Comment: 24 pages, 13 figures, to be submitted to PRD. Comments welcome!

    الوصول الحر: http://arxiv.org/abs/2405.10881Test

  4. 4
    تقرير

    المؤلفون: Bigwood, L., Amon, A., Schneider, A., Salcido, J., McCarthy, I. G., Preston, C., Sanchez, D., Sijacki, D., Schaan, E., Ferraro, S., Battaglia, N., Chen, A., Dodelson, S., Roodman, A., Pieres, A., Ferte, A., Alarcon, A., Drlica-Wagner, A., Choi, A., Navarro-Alsina, A., Campos, A., Ross, A. J., Rosell, A. Carnero, Yin, B., Yanny, B., Sanchez, C., Chang, C., Davis, C., Doux, C., Gruen, D., Rykoff, E. S., Huff, E. M., Sheldon, E., Tarsitano, F., Andrade-Oliveira, F., Bernstein, G. M., Giannini, G., Diehl, H. T., Huang, H., Harrison, I., Sevilla-Noarbe, I., Tutusaus, I., Elvin-Poole, J., McCullough, J., Zuntz, J., Blazek, J., DeRose, J., Cordero, J., Prat, J., Myles, J., Eckert, K., Bechtol, K., Herner, K., Secco, L. F., Gatti, M., Raveri, M., Kind, M. Carrasco, Becker, M. R., Troxel, M. A., Jarvis, M., MacCrann, N., Friedrich, O., Alves, O., Leget, P. -F., Chen, R., Rollins, R. P., Wechsler, R. H., Gruendl, R. A., Cawthon, R., Allam, S., Bridle, S. L., Pandey, S., Everett, S., Shin, T., Hartley, W. G., Fang, X., Zhang, Y., Aguena, M., Annis, J., Bacon, D., Bertin, E., Bocquet, S., Brooks, D., Carretero, J., Castander, F. J., da Costa, L. N., Pereira, M. E. S., De Vicente, J., Desai, S., Doel, P., Ferrero, I., Flaugher, B., Frieman, J., Garcia-Bellido, J., Gaztanaga, E., Gutierrez, G., Hinton, S. R., Hollowood, D. L., Honscheid, K., Huterer, D., James, D. J., Kuehn, K., Lahav, O., Lee, S., Marshall, J. L., Mena-Fernandez, J., Miquel, R., Muir, J., Paterno, M., Malagon, A. A. Plazas, Porredon, A., Romer, A. K., Samuroff, S., Sanchez, E., Cid, D. Sanchez, Smith, M., Soares-Santos, M., Suchyta, E., Swanson, M. E. C., Tarle, G., To, C., Weaverdyck, N., Weller, J., Wiseman, P., Yamamoto, M.

    الوصف: Extracting precise cosmology from weak lensing surveys requires modelling the non-linear matter power spectrum, which is suppressed at small scales due to baryonic feedback processes. However, hydrodynamical galaxy formation simulations make widely varying predictions for the amplitude and extent of this effect. We use measurements of Dark Energy Survey Year 3 weak lensing (WL) and Atacama Cosmology Telescope DR5 kinematic Sunyaev-Zel'dovich (kSZ) to jointly constrain cosmological and astrophysical baryonic feedback parameters using a flexible analytical model, `baryonification'. First, using WL only, we compare the $S_8$ constraints using baryonification to a simulation-calibrated halo model, a simulation-based emulator model and the approach of discarding WL measurements on small angular scales. We find that model flexibility can shift the value of $S_8$ and degrade the uncertainty. The kSZ provides additional constraints on the astrophysical parameters and shifts $S_8$ to $S_8=0.823^{+0.019}_{-0.020}$, a higher value than attained using the WL-only analysis. We measure the suppression of the non-linear matter power spectrum using WL + kSZ and constrain a mean feedback scenario that is more extreme than the predictions from most hydrodynamical simulations. We constrain the baryon fractions and the gas mass fractions and find them to be generally lower than inferred from X-ray observations and simulation predictions. We conclude that the WL + kSZ measurements provide a new and complementary benchmark for building a coherent picture of the impact of gas around galaxies across observations.

    الوصول الحر: http://arxiv.org/abs/2404.06098Test

  5. 5
    تقرير

    الوصف: In cosmological analyses it is common to combine different types of measurement from the same survey. In this paper we use simulated DES Y3 and LSST Y1 data to explore differences in sensitivity to intrinsic alignments (IA) between cosmic shear and galaxy-galaxy lensing. We generate mock shear, galaxy-galaxy lensing and galaxy clustering data, contaminated with a range of IA scenarios. Using a simple 2-parameter IA model (NLA) in a DES Y3 like analysis, we show that the galaxy-galaxy lensing + galaxy clustering combination ($2\times2$pt) is significantly more robust to IA mismodelling than cosmic shear. IA scenarios that produce up to $5\sigma$ biases for shear are seen to be unbiased at the level of $\sim1\sigma$ for $2\times2$pt. We demonstrate that this robustness can be largely attributed to the redshift separation in galaxy-galaxy lensing, which provides a cleaner separation of lensing and IA contributions. We identify secondary factors which may also contribute, including the possibility of cancellation of higher-order IA terms in $2\times2$pt and differences in sensitivity to physical scales. Unfortunately this does not typically correspond to equally effective self-calibration in a $3\times2$pt analysis of the same data, which can show significant biases driven by the cosmic shear part of the data vector. If we increase the precision of our mock analyses to a level roughly equivalent to LSST Y1, we find a similar pattern, with considerably more bias in a cosmic shear analysis than a $2\times2$pt one, and significant bias in a joint analysis of the two. Our findings suggest that IA model error can manifest itself as internal tension between $\xi_\pm$ and $\gamma_t + w$ data vectors. We thus propose that such tension (or the lack thereof) can be employed as a test of model sufficiency or insufficiency when choosing a fiducial IA model, alongside other data-driven methods.
    Comment: Accepted by OJA. 20 pages (excluding appendices)

    الوصول الحر: http://arxiv.org/abs/2402.15573Test

  6. 6
    تقرير

    الوصف: In this paper we present and validate the galaxy sample used for the analysis of the baryon acoustic oscillation (BAO) signal in the Dark Energy Survey (DES) Y6 data. The definition is based on a color and redshift-dependent magnitude cut optimized to select galaxies at redshifts higher than 0.6, while ensuring a high-quality photo-$z$ determination. The optimization is performed using a Fisher forecast algorithm, finding the optimal $i$-magnitude cut to be given by $i$<19.64+2.894$z_{\rm ph}$. For the optimal sample, we forecast an increase in precision in the BAO measurement of $\sim$25% with respect to the Y3 analysis. Our BAO sample has a total of 15,937,556 galaxies in the redshift range 0.6<$z_{\rm ph}$<1.2, and its angular mask covers 4,273.42 deg${}^2$ to a depth of $i$=22.5. We validate its redshift distributions with three different methods: directional neighborhood fitting algorithm (DNF), which is our primary photo-$z$ estimation; direct calibration with spectroscopic redshifts from VIPERS; and clustering redshift using SDSS galaxies. The fiducial redshift distribution is a combination of these three techniques performed by modifying the mean and width of the DNF distributions to match those of VIPERS and clustering redshift. In this paper we also describe the methodology used to mitigate the effect of observational systematics, which is analogous to the one used in the Y3 analysis. This paper is one of the two dedicated to the analysis of the BAO signal in DES Y6. In its companion paper, we present the angular diameter distance constraints obtained through the fitting to the BAO scale.
    Comment: 23 pages, 10 figures. Submitted to PRD

    الوصول الحر: http://arxiv.org/abs/2402.10697Test

  7. 7
    تقرير

    المؤلفون: DES Collaboration, Abbott, T. M. C., Adamow, M., Aguena, M., Allam, S., Alves, O., Amon, A., Andrade-Oliveira, F., Asorey, J., Avila, S., Bacon, D., Bechtol, K., Bernstein, G. M., Bertin, E., Blazek, J., Bocquet, S., Brooks, D., Burke, D. L., Camacho, H., Rosell, A. Carnero, Carollo, D., Carretero, J., Castander, F. J., Cawthon, R., Chan, K. C., Chang, C., Conselice, C., Costanzi, M., Crocce, M., da Costa, L. N., Pereira, M. E. S., Davis, T. M., De Vicente, J., Deiosso, N., Desai, S., Diehl, H. T., Dodelson, S., Doux, C., Drlica-Wagner, A., Elvin-Poole, J., Everett, S., Ferrero, I., Ferté, A., Flaugher, B., Fosalba, P., Frieman, J., García-Bellido, J., Gaztanaga, E., Giannini, G., Gruendl, R. A., Gutierrez, G., Hartley, W. G., Hinton, S. R., Hollowood, D. L., Honscheid, K., Huterer, D., James, D. J., Kent, S., Kuehn, K., Lahav, O., Lee, S., Lidman, C., Lin, H., Marshall, J. L., Martini, P., Mena-Fernández, J., Menanteau, F., Miquel, R., Mohr, J. J., Myles, J., Nichol, R. C., Ogando, R. L. C., Palmese, A., Percival, W. J., Pieres, A., Malagón, A. A. Plazas, Porredon, A., Prat, J., Rodríguez-Monroy, M., Romer, A. K., Roodman, A., Rosenfeld, R., Ross, A. J., Rykoff, E. S., Sako, M., Samuroff, S., Sánchez, C., Sanchez, E., Cid, D. Sanchez, Santiago, B., Schubnell, M., Sevilla-Noarbe, I., Sheldon, E., Smith, M., Suchyta, E., Swanson, M. E. C., Tarle, G., Thomas, D., To, C., Cipriano, L. Toribio San, Troxel, M. A., Tucker, B. E., Tucker, D. L., Walker, A. R., Weaverdyck, N., Weller, J., Wiseman, P., Yanny, B.

    الوصف: We present the angular diameter distance measurement obtained with the Baryonic Acoustic Oscillation feature from galaxy clustering in the completed Dark Energy Survey, consisting of six years (Y6) of observations. We use the Y6 BAO galaxy sample, optimized for BAO science in the redshift range 0.6<$z$<1.2, with an effective redshift at $z_{\rm eff}$=0.85 and split into six tomographic bins. The sample has nearly 16 million galaxies over 4,273 square degrees. Our consensus measurement constrains the ratio of the angular distance to sound horizon scale to $D_M(z_{\rm eff})/r_d$ = 19.51$\pm$0.41 (at 68.3% confidence interval), resulting from comparing the BAO position in our data to that predicted by Planck $\Lambda$CDM via the BAO shift parameter $\alpha=(D_M/r_d)/(D_M/r_d)_{\rm Planck}$. To achieve this, the BAO shift is measured with three different methods, Angular Correlation Function (ACF), Angular Power Spectrum (APS), and Projected Correlation Function (PCF) obtaining $\alpha=$ 0.952$\pm$0.023, 0.962$\pm$0.022, and 0.955$\pm$0.020, respectively, which we combine to $\alpha=$ 0.957$\pm$0.020, including systematic errors. When compared with the $\Lambda$CDM model that best fits Planck data, this measurement is found to be 4.3% and 2.1$\sigma$ below the angular BAO scale predicted. To date, it represents the most precise angular BAO measurement at $z$>0.75 from any survey and the most precise measurement at any redshift from photometric surveys. The analysis was performed blinded to the BAO position and it is shown to be robust against analysis choices, data removal, redshift calibrations and observational systematics.
    Comment: Submitted to PRD, 39 pages, 12 figures

    الوصول الحر: http://arxiv.org/abs/2402.10696Test

  8. 8
    تقرير

    الوصف: Beyond-two-point statistics contain additional information on cosmological as well as astrophysical and observational (systematics) parameters. In this methodology paper we provide an end-to-end simulation-based analysis of a set of Gaussian and non-Gaussian weak lensing statistics using detailed mock catalogues of the Dark Energy Survey. We implement: 1) second and third moments; 2) wavelet phase harmonics (WPH); 3) the scattering transform (ST). Our analysis is fully based on simulations, it spans a space of seven $\nu w$CDM cosmological parameters, and it forward models the most relevant sources of systematics of the data (masks, noise variations, clustering of the sources, intrinsic alignments, and shear and redshift calibration). We implement a neural network compression of the summary statistics, and we estimate the parameter posteriors using a likelihood-free-inference approach. We validate the pipeline extensively, and we find that WPH exhibits the strongest performance when combined with second moments, followed by ST. and then by third moments. The combination of all the different statistics further enhances constraints with respect to second moments, up to 25 per cent, 15 per cent, and 90 per cent for $S_8$, $\Omega_{\rm m}$, and the Figure-Of-Merit ${\rm FoM_{S_8,\Omega_{\rm m}}}$, respectively. We further find that non-Gaussian statistics improve constraints on $w$ and on the amplitude of intrinsic alignment with respect to second moments constraints. The methodological advances presented here are suitable for application to Stage IV surveys from Euclid, Rubin-LSST, and Roman with additional validation on mock catalogues for each survey. In a companion paper we present an application to DES Year 3 data.
    Comment: 25 pages, 18 figures. Comments welcome!

    الوصول الحر: http://arxiv.org/abs/2310.17557Test

  9. 9
    تقرير

    المؤلفون: Shaikh, S., Harrison, I., van Engelen, A., Marques, G. A., Abbott, T. M. C., Aguena, M., Alves, O., Amon, A., An, R., Bacon, D., Battaglia, N., Becker, M. R., Bernstein, G. M., Bertin, E., Blazek, J., Bond, J. R., Brooks, D., Burke, D. L., Calabrese, E., Rosell, A. Carnero, Carretero, J., Cawthon, R., Chang, C., Chen, R., Choi, A., Choi, S. K., da Costa, L. N., Pereira, M. E. S., Darwish, O., Davis, T. M., Desai, S., Devlin, M., Diehl, H. T., Doel, P., Doux, C., Elvin-Poole, J., Farren, G. S., Ferraro, S., Ferrero, I., Ferté, A., Flaugher, B., Frieman, J., Gatti, M., Giannini, G., Giardiello, S., Gruen, D., Gruendl, R. A., Gutierrez, G., Hill, J. C., Hinton, S. R., Hollowood, D. L., Honscheid, K., Huffenberger, K. M., Huterer, D., James, D. J., Jarvis, M., Jeffrey, N., Jense, H. T., Knowles, K., Kim, J., Kramer, D., Lahav, O., Lee, S., Lima, M., MacCrann, N., Madhavacheril, M. S., Marshall, J. L., McCullough, J., Mehta, Y., Mena-Fernández, J., Miquel, R., Mohr, J. J., Moodley, K., Myles, J., Navarro-Alsina, A., Newburgh, L., Niemack, M. D., Omori, Y., Pandey, S., Partridge, B., Pieres, A., Malagón, A. A. Plazas, Porredon, A., Prat, J., Qu, F. J., Robertson, N., Rollins, R. P., Roodman, A., Samuroff, S., Sánchez, C., Sanchez, E., Cid, D. Sanchez, Secco, L. F., Sehgal, N., Sheldon, E., Sherwin, B. D., Shin, T., Smith, C. Sifón M., Suchyta, E., Swanson, M. E. C., Tarle, G., Troxel, M. A., Tutusaus, I., Vargas, C., Weaverdyck, N., Wiseman, P., Yamamoto, M., Zuntz, J.

    الوصف: Cross-correlation between weak lensing of the Cosmic Microwave Background (CMB) and weak lensing of galaxies offers a way to place robust constraints on cosmological and astrophysical parameters with reduced sensitivity to certain systematic effects affecting individual surveys. We measure the angular cross-power spectrum between the Atacama Cosmology Telescope (ACT) DR4 CMB lensing and the galaxy weak lensing measured by the Dark Energy Survey (DES) Y3 data. Our baseline analysis uses the CMB convergence map derived from ACT-DR4 and $\textit{Planck}$ data, where most of the contamination due to the thermal Sunyaev Zel'dovich effect is removed, thus avoiding important systematics in the cross-correlation. In our modelling, we consider the nuisance parameters of the photometric uncertainty, multiplicative shear bias and intrinsic alignment of galaxies. The resulting cross-power spectrum has a signal-to-noise ratio $= 7.1$ and passes a set of null tests. We use it to infer the amplitude of the fluctuations in the matter distribution ($S_8 \equiv \sigma_8 (\Omega_{\rm m}/0.3)^{0.5} = 0.782\pm 0.059$) with informative but well-motivated priors on the nuisance parameters. We also investigate the validity of these priors by significantly relaxing them and checking the consistency of the resulting posteriors, finding them consistent, albeit only with relatively weak constraints. This cross-correlation measurement will improve significantly with the new ACT-DR6 lensing map and form a key component of the joint 6x2pt analysis between DES and ACT.
    Comment: 26 pages, 30 figures (including appendices). Data associated with this article is available at https://github.com/itrharrison/actdr4kappa-x-desy3gamma-dataTest

    الوصول الحر: http://arxiv.org/abs/2309.04412Test

  10. 10
    تقرير

    الوصف: We demonstrate and measure the impact of source galaxy clustering on higher-order summary statistics of weak gravitational lensing data. By comparing simulated data with galaxies that either trace or do not trace the underlying density field, we show this effect can exceed measurement uncertainties for common higher-order statistics for certain analysis choices. Source clustering effects are larger at small scales and for statistics applied to combinations of low and high redshift samples, and diminish at high redshift. We evaluate the impact on different weak lensing observables, finding that third moments and wavelet phase harmonics are more affected than peak count statistics. Using Dark Energy Survey Year 3 data we construct null tests for the source-clustering-free case, finding a $p$-value of $p=4\times10^{-3}$ (2.6 $\sigma$) using third-order map moments and $p=3\times10^{-11}$ (6.5 $\sigma$) using wavelet phase harmonics. The impact of source clustering on cosmological inference can be either be included in the model or minimized through \textit{ad-hoc} procedures (e.g. scale cuts). We verify that the procedures adopted in existing DES Y3 cosmological analyses (using map moments and peaks) were sufficient to render this effect negligible. Failing to account for source clustering can significantly impact cosmological inference from higher-order gravitational lensing statistics, e.g. higher-order N-point functions, wavelet-moment observables (including phase harmonics and scattering transforms), and deep learning or field level summary statistics of weak lensing maps. We provide recipes both to minimise the impact of source clustering and to incorporate source clustering effects into forward-modelled mock data.
    Comment: 5 pages, 2 figures, submitted to MNRAS Letters

    الوصول الحر: http://arxiv.org/abs/2307.13860Test