DECaPS DR2 z HiPS

DECaPS2 is a five-band optical and near-infrared survey of the southern Galactic plane with the Dark Energy Camera (DECam) on the 4.0m Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile. The survey is designed to reach past the main-sequence turn-off at the distance of the Galactic center through a reddening E(B-V) of 1.5 mag, with a typical single-exposure depth of 23.7, 22.7, 22.2, 21.7, and 20.9 mag in the grizY bands, and with average seeing around 1''. The footprint covers | b | < 10 deg , 6 deg > l > - 124 deg (essentially the low latitude Galactic plane south of delta < - 24 deg , a total of about 2700 square degrees (6.5% of the sky). DECaPS2 simultaneously solves for the positions and fluxes of all the sources in each image, delivering positions and fluxes of 3.32 billion stars with up to 5 mmag repeatability. Most of these objects are highly reddened and deep in the Galactic disk, probing the structure and properties of the Milky Way and its interstellar medium.

DECaPS2是一项依托智利塞罗托洛洛美洲际天文台（Cerro Tololo Inter-American Observatory）4.0米布兰科望远镜搭载的暗能量相机（Dark Energy Camera, DECam）开展的南天银道面五波段光学与近红外巡天项目。该巡天旨在通过E(B-V)=1.5星等的星际消光，探测至银河系中心距离处的主序星转捩点（main-sequence turn-off）；其grizY五个波段的单次典型曝光极限星等分别为23.7、22.7、22.2、21.7与20.9星等，平均视宁度约1角秒。其观测天区覆盖|银纬b| < 10°、6° > 银经l > -124°，本质上为赤纬δ < -24°以南的低银纬南天银道面区域，总面积约2700平方度，占全天总面积的6.5%。DECaPS2可同时求解单帧图像中所有天体的位置与流量，共发布了33.2亿颗恒星的位置与测光流量数据，测量重复性可达5毫星等。其中绝大多数天体位于银盘内高消光区域，可用于探究银河系及其星际介质的结构与物理性质。