TY - JOUR
T1 - Brackett lines from the super star cluster nebulae in HE 2-10
AU - Henry, Alaina L.
AU - Turner, Jean L.
AU - Beck, Sara C.
AU - Crosthwaite, Lucian P.
AU - Meier, David S.
PY - 2007/3
Y1 - 2007/3
N2 - We present high spectral resolution (v ∼ 12-16 km s-1) Brackett line spectroscopy of the blue compact dwarf galaxy Henize 2-10 made with NIRSPEC on the Keck telescope. The spatial resolution is seeing-limited, at 1″. We detect two distinct kinematic features separated by approximately 3″, with heliocentric velocities of ∼860 and ∼890 km s -1. In addition to a narrow core, the line profiles also display a broad, low-intensity feature on the blue side of the centroid, which we attribute to an outflow. This may be a sign of aging in the clusters. We compare to archival high-resolution Very Large Array data at 1.3 cm and find that the centimeter-wavelength emission is resolved into six sources. These radio sources are organized into two larger groups, which we associate with the two kinematic peaks in the Brackett spectrum. We estimate a Lyman continuum rate of at least 7 × 1052 s-1, with a corresponding stellar mass of 6 × 106 M⊙ required to ionize the nebulae. We also estimate the size of the nebulae from the radio continuum brightness and find that the observed sources probably contain many H II regions in smaller, unresolved clumps. Brackett line profiles have supersonic line widths but, aside from the blue wing, are comparable to line widths observed in Galactic ultracompact H II regions, which are excited by a single star or a few stars.
AB - We present high spectral resolution (v ∼ 12-16 km s-1) Brackett line spectroscopy of the blue compact dwarf galaxy Henize 2-10 made with NIRSPEC on the Keck telescope. The spatial resolution is seeing-limited, at 1″. We detect two distinct kinematic features separated by approximately 3″, with heliocentric velocities of ∼860 and ∼890 km s -1. In addition to a narrow core, the line profiles also display a broad, low-intensity feature on the blue side of the centroid, which we attribute to an outflow. This may be a sign of aging in the clusters. We compare to archival high-resolution Very Large Array data at 1.3 cm and find that the centimeter-wavelength emission is resolved into six sources. These radio sources are organized into two larger groups, which we associate with the two kinematic peaks in the Brackett spectrum. We estimate a Lyman continuum rate of at least 7 × 1052 s-1, with a corresponding stellar mass of 6 × 106 M⊙ required to ionize the nebulae. We also estimate the size of the nebulae from the radio continuum brightness and find that the observed sources probably contain many H II regions in smaller, unresolved clumps. Brackett line profiles have supersonic line widths but, aside from the blue wing, are comparable to line widths observed in Galactic ultracompact H II regions, which are excited by a single star or a few stars.
KW - Galaxies: ISM
KW - Galaxies: individual (Henize 2-10)
KW - Galaxies: kinematics and dynamics
KW - Galaxies: star clusters
KW - H II regions
KW - Radio continuum: galaxies
UR - https://www.scopus.com/pages/publications/33947541741
U2 - 10.1086/510358
DO - 10.1086/510358
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AN - SCOPUS:33947541741
SN - 0004-6256
VL - 133
SP - 757
EP - 767
JO - Astronomical Journal
JF - Astronomical Journal
IS - 3
ER -