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

Putman, M. E., de Heij, V., Staveley-Smith, L., Braun, R., Freeman, K. C., Gibson, B. K., Burton, W. B., Barnes, D. G., Banks, G. D., Bhathal, R., de Blok, V., Boyce, P. J., Disney, M. J., Drinkwater, M. J., Ekers, R. D., Henning, P. A., Jerjen, H., Kilborn, V. A., Knezek, P. M., Koribalski, B., Malin, D. F., Marquarding, M., Minchin, R. F., Mould, J. R., Oosterloo, T., Price, R. M., Ryder, S. D., Sadler, E. M., Stewart, I., Stootman, F., Webster, R. L. and Wright, A. E. (2002) Hipass high-velocity clouds: Properties of the compact and extended populations. Astronomical Journal, 123 2: 873-891. doi:10.1086/338088

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Author Putman, M. E.
de Heij, V.
Staveley-Smith, L.
Braun, R.
Freeman, K. C.
Gibson, B. K.
Burton, W. B.
Barnes, D. G.
Banks, G. D.
Bhathal, R.
de Blok, V.
Boyce, P. J.
Disney, M. J.
Drinkwater, M. J.
Ekers, R. D.
Henning, P. A.
Jerjen, H.
Kilborn, V. A.
Knezek, P. M.
Koribalski, B.
Malin, D. F.
Marquarding, M.
Minchin, R. F.
Mould, J. R.
Oosterloo, T.
Price, R. M.
Ryder, S. D.
Sadler, E. M.
Stewart, I.
Stootman, F.
Webster, R. L.
Wright, A. E.
Title Hipass high-velocity clouds: Properties of the compact and extended populations
Journal name Astronomical Journal   Check publisher's open access policy
ISSN 1538-3881
Publication date 2002-02
Sub-type Article (original research)
DOI 10.1086/338088
Open Access Status File (Publisher version)
Volume 123
Issue 2
Start page 873
End page 891
Total pages 19
Place of publication Madison, WI, United States
Publisher Institute of Physics Publishing
Language eng
Formatted abstract
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 σ: ΔTB = 0.04 K), resolution (15farcm5), and velocity range (-500 km s-1 < VLSR < +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 ~4.5D2kpc Modot and have similar slopes for their column density and flux 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 VGSR = -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%.
Keyword Astronomy & Astrophysics
Intergalactic Medium
Local Group
Magellanic Clouds
Ly-alpha Forest
H-i Clouds
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collections: Faculty of Health and Behavioural Sciences -- Publications
Excellence in Research Australia (ERA) - Collection
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Citation counts: TR Web of Science Citation Count  Cited 132 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 124 times in Scopus Article | Citations
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Created: Mon, 13 Aug 2007, 12:51:23 EST