TY - JOUR
T1 - Neutral gas distributions and kinematics of five blue compact dwarf galaxies
AU - Van Zee, Liese
AU - Skillman, Evan D.
AU - Salzer, John J.
PY - 1998/9
Y1 - 1998/9
N2 - We present the results of high spatial resolution H I observations of five intrinsically compact dwarf galaxies that are currently experiencing a strong burst of star formation. The H I maps indicate that these systems have a complex and clumpy interstellar medium. Unlike typical dwarf irregular galaxies, these blue compact dwarf galaxies (BCDs) exhibit strong central concentrations in their neutral gas distributions that may provide a clue to the origin of their strong starburst activity. Furthermore, while all of the systems appear to be rotating, based on observed velocity gradients, the kinematics are complex. All systems have nonordered kinematic structure at some level; some of the extended gas is not necessarily kinematically connected to the main system. The observed gas distributions and kinematics place constraints on evolutionary scenarios for BCDs. Evolutionary links between BCDs, dwarf irregular galaxies, and dwarf elliptical galaxies have been postulated to explain their high star formation rates and low-luminosity, low-metallicity nature. The BCDs appear to have higher central mass concentrations in both gas and stellar content than the dwarf irregulars, indicating that evolutionary scenarios connecting these two classes will require mass redistribution. In addition, the fact that BCDs are rotationally supported systems indicates that they are unlikely to evolve into dwarf ellipticals without substantial loss of angular momentum. Thus, while such evolutionary scenarios may still be possible with the aid of mergers or tidal interactions, the isolated nature of BCDs suggests that the majority of BCDs will not fade to become objects similar to the present-day dwarf ellipticals.
AB - We present the results of high spatial resolution H I observations of five intrinsically compact dwarf galaxies that are currently experiencing a strong burst of star formation. The H I maps indicate that these systems have a complex and clumpy interstellar medium. Unlike typical dwarf irregular galaxies, these blue compact dwarf galaxies (BCDs) exhibit strong central concentrations in their neutral gas distributions that may provide a clue to the origin of their strong starburst activity. Furthermore, while all of the systems appear to be rotating, based on observed velocity gradients, the kinematics are complex. All systems have nonordered kinematic structure at some level; some of the extended gas is not necessarily kinematically connected to the main system. The observed gas distributions and kinematics place constraints on evolutionary scenarios for BCDs. Evolutionary links between BCDs, dwarf irregular galaxies, and dwarf elliptical galaxies have been postulated to explain their high star formation rates and low-luminosity, low-metallicity nature. The BCDs appear to have higher central mass concentrations in both gas and stellar content than the dwarf irregulars, indicating that evolutionary scenarios connecting these two classes will require mass redistribution. In addition, the fact that BCDs are rotationally supported systems indicates that they are unlikely to evolve into dwarf ellipticals without substantial loss of angular momentum. Thus, while such evolutionary scenarios may still be possible with the aid of mergers or tidal interactions, the isolated nature of BCDs suggests that the majority of BCDs will not fade to become objects similar to the present-day dwarf ellipticals.
KW - Compact - galaxies
KW - Dwarf - galaxies
KW - Galaxies
KW - Individual (II Zw 40, UGC 4483, UM 439, UM 461, UM 462) - galaxies
KW - Kinematics and dynamics
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U2 - 10.1086/300510
DO - 10.1086/300510
M3 - Article
AN - SCOPUS:0000541628
SN - 0004-6256
VL - 116
SP - 1186
EP - 1204
JO - Astronomical Journal
JF - Astronomical Journal
IS - 3
ER -