Weak Gravitational Lensing around Low Surface Brightness Galaxies in the DES Year 3 Data
N. Chicoine, J. Prat, G. Zacharegkas, C. Chang, D. Tanoglidis, A. Drlica-Wagner, D. Anbajagane, S. Adhikari, A. Amon, R. H. Wechsler, A. Alarcon, K. Bechtol, M.… 展开作者
N. Chicoine, J. Prat, G. Zacharegkas, C. Chang, D. Tanoglidis, A. Drlica-Wagner, D. Anbajagane, S. Adhikari, A. Amon, R. H. Wechsler, A. Alarcon, K. Bechtol, M. R. Becker, G. M. Bernstein, A. Campos, A. Carnero Rosell, M. Carrasco Kind, R. Cawthon, R. Chen, A. Choi, J. Cordero, C. Davis, J. DeRose, S. Dodelson, C. Doux, K. Eckert, J. Elvin-Poole, S. Everett, A. Ferté, M. Gatti, G. Giannini, D. Gruen, R. A. Gruendl, I. Harrison, K. Herner, M. Jarvis, P. -F. Leget, N. MacCrann, J. McCullough, J. Myles, A. Navarro-Alsina, S. Pandey, M. Raveri, R. P. Rollins, A. Roodman, A. J. Ross, E. S. Rykoff, C. Sánchez, L. F. Secco, I. Sevilla-Noarbe, E. Sheldon, T. Shin, M. A. Troxel, I. Tutusaus, T. N. Varga, B. Yanny, B. Yin, J. Zuntz, M. Aguena, O. Alves, D. Bacon, D. Brooks, J. Carretero, F. J. Castander, C. Conselice, S. Desai, J. De Vicente, P. Doel, I. Ferrero, B. Flaugher, J. Frieman, J. García-Bellido, E. Gaztanaga, G. Gutierrez, S. R. Hinton, D. L. Hollowood, K. Honscheid, D. J. James, K. Kuehn, S. Lee, C. Lidman, M. Lima, J. L. Marshall, J. Mena-Fernández, R. Miquel, J. Muir, R. L. C. Ogando, A. Palmese, M. E. S. Pereira, A. Pieres, A. A. Plazas Malagón, A. Porredon, A. R. Walker, S. Samuroff, E. Sanchez, D. Sanchez Cid, M. Smith, E. Suchyta, M. E. C. Swanson, G. Tarle, C. To, D. L. Tucker, V. Vikram, N. Weaverdyck, P. Wiseman
We present galaxy-galaxy lensing measurements using a sample of low surface brightness galaxies (LSBGs) drawn from the Dark Energy Survey Year 3 (Y3) data as lenses. LSBGs are diffuse galaxies with a surface brightness dimmer than the ambient night sky. These dark-matter-dominated objects are intriguing due to potentially unusual formation channels that lead to their diffuse stellar component. Given the faintness of LSBGs, using standard observational techniques to characterize their total masses proves challenging. Weak gravitational lensing, which is less sensitive to the stellar component of galaxies, could be a promising avenue to estimate the masses of LSBGs. Our LSBG sample consists of 23,790 galaxies separated into red and blue color types at $g-i\ge 0.60$ and $g-i< 0.60$, respectively. Combined with the DES Y3 shear catalog, we measure the tangential shear around these LSBGs and find signal-to-noise ratios of 6.67 for the red sample, 2.17 for the blue sample, and 5.30 for the full sample. We use the clustering redshifts method to obtain redshift distributions for the red and blue LSBG samples. Assuming all red LSBGs are satellites, we fit a simple model to the measurements and estimate the host halo mass of these LSBGs to be $\log(M_{\rm host}/M_{\odot}) = 12.98 ^{+0.10}_{-0.11}$. We place a 95% upper bound on the subhalo mass at $\log(M_{\rm sub}/M_{\odot})<11.51$. By contrast, we assume the blue LSBGs are centrals, and place a 95% upper bound on the halo mass at $\log(M_\mathrm{host}/M_\odot) < 11.84$. We find that the stellar-to-halo mass ratio of the LSBG samples is consistent with that of the general galaxy population. This work illustrates the viability of using weak gravitational lensing to constrain the halo masses of LSBGs.
Galaxy Ellipticity Measurements in the Near-Infrared for Weak Lensing
我们调查的价值，近红外成像从即将到来的调查约束星系的椭圆。我们选择的星系之间的0.5 < z < 3比预期的欧几里德灵敏度限制从GOODS-S和N领域在CANDELS。共同添加的CANDELS/HST V+I和J+H图像的分辨率和灵敏度降低，以模拟欧几里得质量的光学和近红外（NIR）图像。然后我们对这些模拟图像运行GALFIT，发现光学和近红外在测量星系椭圆率方面提供了类似的性能，在红移0.5 < z < 3. At z >1.0时，近红外选择的源密度高出1.4倍，因此近红外推导的椭圆率的标准误差小了约30%，这意味着更精确的椭圆率测量。近红外光谱的良好性能主要是因为星系在近红外波段的光分布比光学波段的光分布更平滑，后者追踪的是星团的恒星形成区域。此外，NIR波段的每像素表面亮度比光学图像高，同时受灰尘衰减的影响较小。尽管欧几里德近红外光谱的空间采样和分辨率比光学差，但近红外光谱的方法可以产生等效或更精确的星系椭圆率测量。如果影响形状的系统学，如抖动策略和点扩散函数欠采样可以减轻，包括近红外光谱可以改善星系椭圆率测量所有的红移。这对于即将到来的弱透镜调查特别重要，例如Euclid和WFIRST。
Resolving on 100 pc scales the UV-continuum in Lyman-$α$ emitters between redshift 2 to 3 with gravitational lensing
我们提出了一个研究的17个LAEs在红移2 $<z<$ 3引力透镜的大质量早型星系（ETGs）的平均红移约为0.5。使用一个完全贝叶斯网格为基础的技术，我们模拟的引力透镜质量分布与椭圆幂律配置文件和重建的UV连续表面亮度分布的背景源，使用像素化的源模型。我们发现，偏转器接近，但不符合等温模型在几乎所有情况下，在$2σ$水平。我们利用透镜放大率（通常为$μ\simeq$ 20）的优势，这些LAE星系的物理和形态学特性。从重建的紫外连续辐射，我们发现，恒星形成率范围从0.3至8.5 M $_{\odot}$年$^{-1}$和星系通常由几个紧凑和弥漫的组件，由0.4至4千秒差距。此外，它们的恒星形成率峰值强度范围从2.1到54.1 M $_{\odot}$ yr $^{-1}$ kpc $^{-2}$。这些星系倾向于延伸，长轴范围从0.2到1.8千秒差距（中位数561秒差距），椭圆率中位数为0.49。这种形态与超过一半的样品的星形形成的盘状结构一致。然而，对于至少两个源，我们也发现离轴组件，可能与合并。将需要解析的运动学信息来确认样品中LAE的盘状性质和可能的合并情况。
