Outlying H II regions in H I-selected galaxies

J. K. Werk; M. E. Putman; G. R. Meurer; E. V. Ryan-Weber; C. Kehrig; D. A. Thilker; J. Bland-Hawthorn; M. J. Drinkwater; R. C. Kennicutt; O. I. Wong; K. C. Freeman; M. S. Oey; M. A. Dopita; M. T. Doyle; H. C. Ferguson; D. J. Hanish; T. M. Heckman; V. A. Kilborn; J. H. Kim; P. M. Knezek; B. Koribalski; M. Meyer; R. C. Smith; M. A. Zwaan

doi:10.1088/0004-6256/139/1/279

Outlying H II regions in H I-selected galaxies

J. K. Werk, M. E. Putman, G. R. Meurer, E. V. Ryan-Weber, C. Kehrig, D. A. Thilker, J. Bland-Hawthorn, M. J. Drinkwater, R. C. Kennicutt, O. I. Wong, K. C. Freeman, M. S. Oey, M. A. Dopita, M. T. Doyle, H. C. Ferguson, D. J. Hanish, T. M. Heckman, V. A. Kilborn, J. H. Kim, P. M. KnezekB. Koribalski, M. Meyer, R. C. Smith, M. A. Zwaan

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Abstract

We present results from the first systematic search for outlying H II regions, as part of a sample of 96 emission-line point sources (referred to as ELdots-emission-line dots) derived from the NOAO Survey for Ionization in Neutral Gas Galaxies (SINGG). Our automated ELdot finder searches SINGG narrowband and continuum images for high equivalent width point sources outside the optical radius of the target galaxy (>2 × r₂₅ in the R band). Follow-up long-slit spectroscopy and deep Galaxy Evolution Explorer (GALEX) images (exposure time >1000 s) distinguish outlying H II regions from background galaxies whose strong emission lines ([O III], Hβ, or [O II]) have been redshifted into the SINGG bandpass. We find that these deep GALEX images can serve as a substitute for spectroscopic follow-up because outlying H II regions separate cleanly from background galaxies in color-color space. We identify seven SINGG systems with outlying massive star formation that span a large range in Hα luminosities corresponding to a few O stars in the most nearby cases, and unresolved dwarf satellite companion galaxies in the most distant cases. Six of these seven systems feature galaxies with nearby companions or interacting galaxies. Furthermore, our results indicate that some outlying H II regions are linked to the extended-UV disks discovered by GALEX, representing emission from the most massive O stars among a more abundant population of lower-mass (or older) star clusters. The overall frequency of outlying H II regions in this sample of gas-rich galaxies is 8%-11% when we correct for background emission-line galaxy contamination (∼75% of ELdots).

Original language	English
Pages (from-to)	279-295
Number of pages	17
Journal	Astronomical Journal
Volume	139
Issue number	1
DOIs	https://doi.org/10.1088/0004-6256/139/1/279
Publication status	Published - 2010

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10.1088/0004-6256/139/1/279

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Werk, J. K., Putman, M. E., Meurer, G. R., Ryan-Weber, E. V., Kehrig, C., Thilker, D. A., Bland-Hawthorn, J., Drinkwater, M. J., Kennicutt, R. C., Wong, O. I., Freeman, K. C., Oey, M. S., Dopita, M. A., Doyle, M. T., Ferguson, H. C., Hanish, D. J., Heckman, T. M., Kilborn, V. A., Kim, J. H., ... Zwaan, M. A. (2010). Outlying H II regions in H I-selected galaxies. Astronomical Journal, 139(1), 279-295. https://doi.org/10.1088/0004-6256/139/1/279

@article{4756d3c17b60436891b514bcf27fc956,

title = "Outlying H II regions in H I-selected galaxies",

abstract = "We present results from the first systematic search for outlying H II regions, as part of a sample of 96 emission-line point sources (referred to as ELdots-emission-line dots) derived from the NOAO Survey for Ionization in Neutral Gas Galaxies (SINGG). Our automated ELdot finder searches SINGG narrowband and continuum images for high equivalent width point sources outside the optical radius of the target galaxy (>2 × r25 in the R band). Follow-up long-slit spectroscopy and deep Galaxy Evolution Explorer (GALEX) images (exposure time >1000 s) distinguish outlying H II regions from background galaxies whose strong emission lines ([O III], Hβ, or [O II]) have been redshifted into the SINGG bandpass. We find that these deep GALEX images can serve as a substitute for spectroscopic follow-up because outlying H II regions separate cleanly from background galaxies in color-color space. We identify seven SINGG systems with outlying massive star formation that span a large range in Hα luminosities corresponding to a few O stars in the most nearby cases, and unresolved dwarf satellite companion galaxies in the most distant cases. Six of these seven systems feature galaxies with nearby companions or interacting galaxies. Furthermore, our results indicate that some outlying H II regions are linked to the extended-UV disks discovered by GALEX, representing emission from the most massive O stars among a more abundant population of lower-mass (or older) star clusters. The overall frequency of outlying H II regions in this sample of gas-rich galaxies is 8%-11% when we correct for background emission-line galaxy contamination (∼75% of ELdots).",

keywords = "Galaxies: halos, Galaxies: star clusters, H II regions, Intergalactic medium, Stars: formation",

author = "Werk, {J. K.} and Putman, {M. E.} and Meurer, {G. R.} and Ryan-Weber, {E. V.} and C. Kehrig and Thilker, {D. A.} and J. Bland-Hawthorn and Drinkwater, {M. J.} and Kennicutt, {R. C.} and Wong, {O. I.} and Freeman, {K. C.} and Oey, {M. S.} and Dopita, {M. A.} and Doyle, {M. T.} and Ferguson, {H. C.} and Hanish, {D. J.} and Heckman, {T. M.} and Kilborn, {V. A.} and Kim, {J. H.} and Knezek, {P. M.} and B. Koribalski and M. Meyer and Smith, {R. C.} and Zwaan, {M. A.}",

year = "2010",

doi = "10.1088/0004-6256/139/1/279",

language = "English",

volume = "139",

pages = "279--295",

journal = "Astronomical Journal",

issn = "0004-6256",

publisher = "American Astronomical Society",

number = "1",

}

Werk, JK, Putman, ME, Meurer, GR, Ryan-Weber, EV, Kehrig, C, Thilker, DA, Bland-Hawthorn, J, Drinkwater, MJ, Kennicutt, RC, Wong, OI, Freeman, KC, Oey, MS, Dopita, MA, Doyle, MT, Ferguson, HC, Hanish, DJ, Heckman, TM, Kilborn, VA, Kim, JH, Knezek, PM, Koribalski, B, Meyer, M, Smith, RC & Zwaan, MA 2010, 'Outlying H II regions in H I-selected galaxies', Astronomical Journal, vol. 139, no. 1, pp. 279-295. https://doi.org/10.1088/0004-6256/139/1/279

TY - JOUR

T1 - Outlying H II regions in H I-selected galaxies

AU - Werk, J. K.

AU - Putman, M. E.

AU - Meurer, G. R.

AU - Ryan-Weber, E. V.

AU - Kehrig, C.

AU - Thilker, D. A.

AU - Bland-Hawthorn, J.

AU - Drinkwater, M. J.

AU - Kennicutt, R. C.

AU - Wong, O. I.

AU - Freeman, K. C.

AU - Oey, M. S.

AU - Dopita, M. A.

AU - Doyle, M. T.

AU - Ferguson, H. C.

AU - Hanish, D. J.

AU - Heckman, T. M.

AU - Kilborn, V. A.

AU - Kim, J. H.

AU - Knezek, P. M.

AU - Koribalski, B.

AU - Meyer, M.

AU - Smith, R. C.

AU - Zwaan, M. A.

PY - 2010

Y1 - 2010

N2 - We present results from the first systematic search for outlying H II regions, as part of a sample of 96 emission-line point sources (referred to as ELdots-emission-line dots) derived from the NOAO Survey for Ionization in Neutral Gas Galaxies (SINGG). Our automated ELdot finder searches SINGG narrowband and continuum images for high equivalent width point sources outside the optical radius of the target galaxy (>2 × r25 in the R band). Follow-up long-slit spectroscopy and deep Galaxy Evolution Explorer (GALEX) images (exposure time >1000 s) distinguish outlying H II regions from background galaxies whose strong emission lines ([O III], Hβ, or [O II]) have been redshifted into the SINGG bandpass. We find that these deep GALEX images can serve as a substitute for spectroscopic follow-up because outlying H II regions separate cleanly from background galaxies in color-color space. We identify seven SINGG systems with outlying massive star formation that span a large range in Hα luminosities corresponding to a few O stars in the most nearby cases, and unresolved dwarf satellite companion galaxies in the most distant cases. Six of these seven systems feature galaxies with nearby companions or interacting galaxies. Furthermore, our results indicate that some outlying H II regions are linked to the extended-UV disks discovered by GALEX, representing emission from the most massive O stars among a more abundant population of lower-mass (or older) star clusters. The overall frequency of outlying H II regions in this sample of gas-rich galaxies is 8%-11% when we correct for background emission-line galaxy contamination (∼75% of ELdots).

AB - We present results from the first systematic search for outlying H II regions, as part of a sample of 96 emission-line point sources (referred to as ELdots-emission-line dots) derived from the NOAO Survey for Ionization in Neutral Gas Galaxies (SINGG). Our automated ELdot finder searches SINGG narrowband and continuum images for high equivalent width point sources outside the optical radius of the target galaxy (>2 × r25 in the R band). Follow-up long-slit spectroscopy and deep Galaxy Evolution Explorer (GALEX) images (exposure time >1000 s) distinguish outlying H II regions from background galaxies whose strong emission lines ([O III], Hβ, or [O II]) have been redshifted into the SINGG bandpass. We find that these deep GALEX images can serve as a substitute for spectroscopic follow-up because outlying H II regions separate cleanly from background galaxies in color-color space. We identify seven SINGG systems with outlying massive star formation that span a large range in Hα luminosities corresponding to a few O stars in the most nearby cases, and unresolved dwarf satellite companion galaxies in the most distant cases. Six of these seven systems feature galaxies with nearby companions or interacting galaxies. Furthermore, our results indicate that some outlying H II regions are linked to the extended-UV disks discovered by GALEX, representing emission from the most massive O stars among a more abundant population of lower-mass (or older) star clusters. The overall frequency of outlying H II regions in this sample of gas-rich galaxies is 8%-11% when we correct for background emission-line galaxy contamination (∼75% of ELdots).

KW - Galaxies: halos

KW - Galaxies: star clusters

KW - H II regions

KW - Intergalactic medium

KW - Stars: formation

UR - http://www.scopus.com/inward/record.url?scp=73049094989&partnerID=8YFLogxK

U2 - 10.1088/0004-6256/139/1/279

DO - 10.1088/0004-6256/139/1/279

M3 - Article

SN - 0004-6256

VL - 139

SP - 279

EP - 295

JO - Astronomical Journal

JF - Astronomical Journal

IS - 1

ER -

Outlying H II regions in H I-selected galaxies

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