Kinematics of disk galaxies in clusters at z=1.5. (arXiv:1903.10016v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Boehm_A/0/1/0/all/0/1">A. Boehm</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ziegler_B/0/1/0/all/0/1">B.L. Ziegler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perez_Martinez_J/0/1/0/all/0/1">J.M. Perez-Martinez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kodama_T/0/1/0/all/0/1">T. Kodama</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hayashi_M/0/1/0/all/0/1">M. Hayashi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Maier_C/0/1/0/all/0/1">C. Maier</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Verdugo_M/0/1/0/all/0/1">M. Verdugo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Koyama_Y/0/1/0/all/0/1">Y. Koyama</a>
We observed star-forming galaxies at z~1.5 selected from the HyperSuprimeCam
Subaru Strategic Program. The galaxies are part of two significant
overdensities of [OII] emitters identified via narrow-band imaging and
photometric redshifts from grizy photometry. We used VLT/KMOS to carry out
Halpha integral field spectroscopy of 46 galaxies in total. Ionized gas maps,
star formation rates and velocity fields were derived from the Halpha emission
line. We quantified morphological and kinematical asymmetries to test for
potential gravitational (e.g. galaxy-galaxy) or hydrodynamical (e.g.
ram-pressure) interactions. Halpha emission was detected in 36 targets. 34 of
the galaxies are members of two clusters at z=1.47, confirming our selection
strategy to be highly efficient. Two galaxies are field objects at slightly
lower redshifts. By fitting model velocity fields to the observed ones, we
determined the intrinsic maximum rotation velocity Vmax of 14 galaxies.
Utilizing the luminosity-velocity (Tully-Fisher) relation, we find that these
galaxies are more luminous than their local counterparts of similar mass by up
to several magnitudes in the rest-frame B-band. In contrast to field galaxies
at z<1, the offsets of the z~1.5 cluster galaxies from the local Tully-Fisher
relation are not correlated with their star formation rates but with the ratio
between Vmax and gas velocity dispersion sigma_g. This probably reflects that,
as is observed in the field at similar redshifts, fewer disks have settled to
purely rotational kinematics and high Vmax/sigma_g ratios. The distributions in
morphological and kinematical asymmetries hint that either the two clusters
under scrutiny do not have a dense intra-cluster medium yet, or galaxy-galaxy
interactions are frequent, making it difficult to identify cases of purely
hydrodynamical interactions between the intra-cluster and interstellar medium.
(abbr.)
We observed star-forming galaxies at z~1.5 selected from the HyperSuprimeCam
Subaru Strategic Program. The galaxies are part of two significant
overdensities of [OII] emitters identified via narrow-band imaging and
photometric redshifts from grizy photometry. We used VLT/KMOS to carry out
Halpha integral field spectroscopy of 46 galaxies in total. Ionized gas maps,
star formation rates and velocity fields were derived from the Halpha emission
line. We quantified morphological and kinematical asymmetries to test for
potential gravitational (e.g. galaxy-galaxy) or hydrodynamical (e.g.
ram-pressure) interactions. Halpha emission was detected in 36 targets. 34 of
the galaxies are members of two clusters at z=1.47, confirming our selection
strategy to be highly efficient. Two galaxies are field objects at slightly
lower redshifts. By fitting model velocity fields to the observed ones, we
determined the intrinsic maximum rotation velocity Vmax of 14 galaxies.
Utilizing the luminosity-velocity (Tully-Fisher) relation, we find that these
galaxies are more luminous than their local counterparts of similar mass by up
to several magnitudes in the rest-frame B-band. In contrast to field galaxies
at z<1, the offsets of the z~1.5 cluster galaxies from the local Tully-Fisher
relation are not correlated with their star formation rates but with the ratio
between Vmax and gas velocity dispersion sigma_g. This probably reflects that,
as is observed in the field at similar redshifts, fewer disks have settled to
purely rotational kinematics and high Vmax/sigma_g ratios. The distributions in
morphological and kinematical asymmetries hint that either the two clusters
under scrutiny do not have a dense intra-cluster medium yet, or galaxy-galaxy
interactions are frequent, making it difficult to identify cases of purely
hydrodynamical interactions between the intra-cluster and interstellar medium.
(abbr.)
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