Reference Calibration for Precision Dark Energy Measurement

用于精密暗能量测量的参考校准

• 批准号: 341310-2012
• 负责人: Albert, Justin
• 金额: $ 1.82万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=572228
• 关键词: Reference; Calibration; Precision; Dark; Energy

Uncertainties on photometric standards now constitute the dominant uncertainty on our knowledge of dark energy. Additionally, they constitute a significant systematic for measurements of stellar population in galaxy cluster counts, and upcoming photometric redshift surveys measuring growth of structure. There are prospects for improvement in uncertainties from standard star flux, but the traditional techniques of measurement of stellar flux from above the atmosphere suffer from basic and inherent problems: the variability of all stellar sources, and the difficulty of creating a precisely calibrated, cross-checked, and stable platform for observation above Earth's atmosphere. We are undertaking a program of research to understand and profoundly reduce the many astrophysical and cosmological uncertainties due to photometry. Presently, together with colleagues at Toronto, McGill, NRC-INMS, and U.S. institutions, we have designed and constructed payloads for high-altitude balloons containing both monochromatic light sources and radiometric calibration. Our balloon flights have begun to overfly observatories, starting with our initial test flight in New Hampshire in August 2011, and continuing with a campaign of flights over the Univ. of New Mexico campus observatory and Mt. Hopkins in Arizona in 2012, and the following year with the CTIO and Las Campanas observatories in Chile. We have constructed and are the responsible party for the payload optics, including the light source, integrating sphere, and regulated power supply. As well as our initial free-flying balloon payload, both a teststand, and a calibrated payload on a tethered weather balloon, are taking data on an optical table and with the new 32" UVic telescope observatory, respectively. Together with an RTI grant with Canadian colleagues submitted separately, we presently request funding for an MSc student to analyze the data from the overflights, as well as from our calibrated lightsource observations at UVic. The longer-term goals of the program are calibrated sources on a nanosatellite, as well as on a controlled high-altitude miniature blimp, to fly directly "in front of" SNIa, and allow observatories across the world to reach the then-technology-limited precision of 0.01% photometry.

光度标准的不确定性现在构成了我们对暗能量知识的主要不确定性。 此外，它们构成了一个重要的系统，用于测量星系团计数中的恒星数量，以及即将进行的测量结构增长的光度红移调查。标准恒星通量的不确定性有望得到改善，但从大气层上方测量恒星通量的传统技术存在基本和固有的问题：所有恒星源的可变性，以及创建精确校准的交叉通量的困难。经过检查的、稳定的地球大气层上方观测平台。 我们正在进行一项研究计划，以了解并深刻减少由于光度测定而带来的许多天体物理和宇宙学不确定性。目前，我们与多伦多、麦吉尔、NRC-INMS 和美国机构的同事一起，设计并建造了包含单色光源和辐射校准的高空气球有效载荷。我们的气球飞行已经开始飞越天文台，从 2011 年 8 月在新罕布什尔州的首次试飞开始，并继续在大学上空进行飞行活动。 2012 年与亚利桑那州新墨西哥校区天文台和霍普金斯山天文台合作，次年与智利 CTIO 和拉斯坎帕纳斯天文台合作。 我们建造并负责有效载荷光学器件，包括光源、积分球和稳压电源。除了我们最初的自由飞行气球有效载荷外，测试台和系留气象气球上的校准有效载荷都分别在光学平台和新的 32 英寸 UVic 望远镜天文台上获取数据。加拿大同事单独提交，我们目前请求为一名理学硕士学生提供资金，以分析飞越的数据以及我们在维多利亚大学校准的光源观测数据。该计划的长期目标已得到校准。纳米卫星以及受控高空微型飞艇上的光源直接飞到 SNIa 的“前面”，使世界各地的天文台能够达到当时技术限制的 0.01% 光度测量精度。