We present the design and implementation of a medium-band near-IR filter tailored for detecting low-mass stars and brown dwarfs from the summit of Maunakea. The W-band filter is centered at 1.45 micron with a bandpass width of 6%, designed to measure the depth of the H2O water absorption prominent in objects with spectral types of M6 and later. When combined with standard J- and H-band photometry, the W-band filter is designed to determine spectral types to $\approx$1.4 subtypes for late-M and L dwarfs, largely independent of surface gravity and reddening. This filter's primary application is completing the census of young substellar objects in star-forming regions, using W-band selection to greatly reduce contamination by reddened background stars that impede broad-band imaging surveys. We deployed the filter on the UH 88-inch telescope to survey $\approx$3 sq. deg. of the NGC 1333, IC 348, and rho Ophiuchus star-forming regions. Our spectroscopic followup of W-band selected candidates resulted in the confirmation of 48 ultracool dwarfs with a success rate of 89%, demonstrating the efficacy of this new filter and selection method.

中文翻译：

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使用 W 波段滤波器对年轻的亚恒星天体进行新的调查。一、蛇夫座和珀尔修斯的过滤器设计和新发现

我们介绍了一种中频近红外滤光片的设计和实现，该滤光片专为探测莫纳基亚峰顶的低质量恒星和褐矮星而设计。W 波段滤光片以 1.45 微米为中心，带通宽度为 6%，旨在测量光谱类型为 M6 及更高的物体中突出的 H2O 吸水深度。当与标准的 J 和 H 波段光度测量相结合时，W 波段滤光片旨在确定晚 M 和 L 矮星大约 1.4 个亚型的光谱类型，很大程度上独立于表面重力和变红。该过滤器的主要应用是完成对恒星形成区域中年轻星下物体的普查，使用 W 波段选择来大大减少阻碍宽带成像调查的变红背景恒星的污染。我们在 UH 88 英寸望远镜上部署了过滤器，以测量 $\approx$3 平方度。NGC 1333、IC 348 和 Rho Ophiuchus 恒星形成区。我们对 W 波段选定候选者的光谱跟踪结果确认了 48 颗超冷矮星，成功率为 89%，证明了这种新过滤器和选择方法的有效性。