首页> 外文期刊>The Astronomical journal >Hipass high-velocity clouds: Properties of the compact and extended populations
【24h】

Hipass high-velocity clouds: Properties of the compact and extended populations

机译:Hipass high-velocity clouds: Properties of the compact and extended populations

获取原文
获取原文并翻译 | 示例
           

摘要

A catalog of southern anomalous-velocity H I clouds at decl. < + 2 is presented. This catalog is based on data from the H I Parkes All-Sky Survey (HIPASS) reprocessed with the MINMED5 procedure and searched with a new high-velocity cloud-finding algorithm. The improved sensitivity (5 sigma;: UDelta;T-B = 0.04 K), resolution (15.'5), and velocity range (-500 km s(-1) < V-LSR < +500 km s(-1)) of the HIPASS data result in a substantial increase in the number of individual clouds (1956, as well as 41 galaxies) compared with what was known from earlier southern data. The method of cataloging the anomalous-velocity objects is described, and a catalog of key cloud parameters, including velocity, angular size, peak column density, total flux, position angle, and degree of isolation, is presented. The data are characterized into several classes of anomalous-velocity H I emission. Most high-velocity emission features are HVCs and have a filamentary morphology and are loosely organized into large complexes extending over tens of degrees. In addition, 179 compact and isolated anomalous-velocity objects, CHVCs, are identified based on their size and degree of isolation. Of the CHVCs originally classified by Braun Burton, 25 are reclassified based on the HIPASS data. The properties of all the high-velocity emission features and only the CHVCs are investigated, and distinct similarities and differences are found. Both populations have typical H I masses of SIM;4.5 D-kpc(2) M. and have similar slopes for their column density and ux distributions. On the other hand, the CHVCs appear to be clustered and the population can be broken up into three spatially distinct groups, while the entire population of clouds is more uniformly distributed with a significant percentage aligned with the Magellanic Stream. The median velocities are V-GSR = -38 km s(-1) for the CHVCs and 30 km s(-1) for all the anomalous-velocity clouds. Based on the catalog sizes, high-velocity features cover 19 of the southern sky, and CHVCs cover 1. References: 62
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号