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

M. E. Putman; V. De Heij; L. Staveley-Smith; R. Braun; K. C. Freeman; B. K. Gibson; W. B. Burton; D. G. Barnes; G. D. Banks; R. Bhathal; W. J.G. De Blok; P. J. Boyce; M. J. Disney; M. J. Drinkwater; R. D. Ekers; P. A. Henning; H. Jerjen; V. A. Kilborn; P. M. Knezek; B. Koribalski; D. F. Malin; M. Marquarding; R. F. Minchin; J. R. Mould; T. Oosterloo; R. M. Price; S. D. Ryder; E. M. Sadler; I. Stewart; F. Stootman; R. L. Webster; A. E. Wright

doi:10.1086/338088

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

M. E. Putman^*, V. De Heij, L. Staveley-Smith, R. Braun, K. C. Freeman, B. K. Gibson, W. B. Burton, D. G. Barnes, G. D. Banks, R. Bhathal, W. J.G. De Blok, P. J. Boyce, M. J. Disney, M. J. Drinkwater, R. D. Ekers, P. A. Henning, H. Jerjen, V. A. Kilborn, P. M. Knezek, B. KoribalskiD. F. Malin, M. Marquarding, R. F. Minchin, J. R. Mould, T. Oosterloo, R. M. Price, S. D. Ryder, E. M. Sadler, I. Stewart, F. Stootman, R. L. Webster, A. E. Wright

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

157 Citations (Scopus)

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: δT_B = 0.04 K), resolution (157prime;.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 ∼4.5D_kpc² M⊙ 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 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%.

Original language	English
Pages (from-to)	873-891
Number of pages	19
Journal	Astronomical Journal
Volume	123
Issue number	2 1754
DOIs	https://doi.org/10.1086/338088
Publication status	Published - Feb 2002

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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, W. J. G., Boyce, P. J., Disney, M. J., Drinkwater, M. J., Ekers, R. D., Henning, P. A., Jerjen, H., Kilborn, V. A., Knezek, P. M., ... Wright, A. E. (2002). Hipass high-velocity clouds: Properties of the compact and extended populations. Astronomical Journal, 123(2 1754), 873-891. https://doi.org/10.1086/338088

@article{c826835492b846168a443a0996c52fa1,

title = "Hipass high-velocity clouds: Properties of the compact and extended populations",

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 (157prime;.5), 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 ∼4.5Dkpc2 M⊙ 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%.",

keywords = "Galaxy: halo, ISM: H I, Intergalacticmedium, Local Group, Magellanic Clouds",

author = "Putman, {M. E.} and {De Heij}, V. and L. Staveley-Smith and R. Braun and Freeman, {K. C.} and Gibson, {B. K.} and Burton, {W. B.} and Barnes, {D. G.} and Banks, {G. D.} and R. Bhathal and {De Blok}, {W. J.G.} and Boyce, {P. J.} and Disney, {M. J.} and Drinkwater, {M. J.} and Ekers, {R. D.} and Henning, {P. A.} and H. Jerjen and Kilborn, {V. A.} and Knezek, {P. M.} and B. Koribalski and Malin, {D. F.} and M. Marquarding and Minchin, {R. F.} and Mould, {J. R.} and T. Oosterloo and Price, {R. M.} and Ryder, {S. D.} and Sadler, {E. M.} and I. Stewart and F. Stootman and Webster, {R. L.} and Wright, {A. E.}",

year = "2002",

month = feb,

doi = "10.1086/338088",

language = "English",

volume = "123",

pages = "873--891",

journal = "Astronomical Journal",

issn = "0004-6256",

publisher = "American Astronomical Society",

number = "2 1754",

}

Putman, ME, De Heij, V, Staveley-Smith, L, Braun, R, Freeman, KC, Gibson, BK, Burton, WB, Barnes, DG, Banks, GD, Bhathal, R, De Blok, WJG, Boyce, PJ, Disney, MJ, Drinkwater, MJ, Ekers, RD, Henning, PA, Jerjen, H, Kilborn, VA, Knezek, PM, Koribalski, B, Malin, DF, Marquarding, M, Minchin, RF, Mould, JR, Oosterloo, T, Price, RM, Ryder, SD, Sadler, EM, Stewart, I, Stootman, F, Webster, RL & Wright, AE 2002, 'Hipass high-velocity clouds: Properties of the compact and extended populations', Astronomical Journal, vol. 123, no. 2 1754, pp. 873-891. https://doi.org/10.1086/338088

TY - JOUR

T1 - Hipass high-velocity clouds

T2 - Properties of the compact and extended populations

AU - Putman, M. E.

AU - De Heij, V.

AU - Staveley-Smith, L.

AU - Braun, R.

AU - Freeman, K. C.

AU - Gibson, B. K.

AU - Burton, W. B.

AU - Barnes, D. G.

AU - Banks, G. D.

AU - Bhathal, R.

AU - De Blok, W. J.G.

AU - Boyce, P. J.

AU - Disney, M. J.

AU - Drinkwater, M. J.

AU - Ekers, R. D.

AU - Henning, P. A.

AU - Jerjen, H.

AU - Kilborn, V. A.

AU - Knezek, P. M.

AU - Koribalski, B.

AU - Malin, D. F.

AU - Marquarding, M.

AU - Minchin, R. F.

AU - Mould, J. R.

AU - Oosterloo, T.

AU - Price, R. M.

AU - Ryder, S. D.

AU - Sadler, E. M.

AU - Stewart, I.

AU - Stootman, F.

AU - Webster, R. L.

AU - Wright, A. E.

PY - 2002/2

Y1 - 2002/2

N2 - 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 (157prime;.5), 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 ∼4.5Dkpc2 M⊙ 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%.

AB - 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 (157prime;.5), 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 ∼4.5Dkpc2 M⊙ 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%.

KW - Galaxy: halo

KW - ISM: H I

KW - Intergalacticmedium

KW - Local Group

KW - Magellanic Clouds

UR - http://www.scopus.com/inward/record.url?scp=0000598350&partnerID=8YFLogxK

U2 - 10.1086/338088

DO - 10.1086/338088

M3 - Article

SN - 0004-6256

VL - 123

SP - 873

EP - 891

JO - Astronomical Journal

JF - Astronomical Journal

IS - 2 1754

ER -

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

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