228 research outputs found
Evolutionary phases of gas-rich galaxies in a galaxy cluster at z=1.46
We report a survey of molecular gas in galaxies in the XMMXCS J2215.9-1738
cluster at . We have detected emission lines from 17 galaxies within a
radius of from the cluster center, in Band 3 data of the Atacama
Large Millimeter/submillimeter Array (ALMA) with a coverage of 93 -- 95 GHz in
frequency and 2.33 arcmin in spatial direction. The lines are all
identified as CO =2--1 emission lines from cluster members at by
their redshifts and the colors of their optical and near-infrared (NIR)
counterparts. The line luminosities reach down to K km s pc. The spatial distribution of
galaxies with a detection of CO(2--1) suggests that they disappear from the
very center of the cluster. The phase-space diagram showing relative velocity
versus cluster-centric distance indicates that the gas-rich galaxies have
entered the cluster more recently than the gas-poor star-forming galaxies and
passive galaxies located in the virialized region of this cluster. The results
imply that the galaxies have experienced ram-pressure stripping and/or
strangulation during the course of infall towards the cluster center and then
the molecular gas in the galaxies at the cluster center is depleted by star
formation.Comment: 7 pages, 4 figures, 1 table, accepted for publication in the ApJ
Letter
A Search for Molecular Gas toward a BzK-selected Star-forming Galaxy at z = 2.044
We present a search for CO(3-2) emission in SDF-26821, a BzK-selected
star-forming galaxy (sBzK) at z = 2.044, using the 45-m telescope of the
Nobeyama Radio Observatory and the Nobeyama Millimeter Array. We do not detect
significant emission and derive 2 \sigma limits: the CO luminosity of L'CO <
3.1 x 10^10 K km s^{-1} pc^{-2}, the ratio of far-infrared luminosity to CO
luminosity of L_FIR/L'CO > 57 Lsun (K km s^{-1} pc^{-2})^{-1}, and the
molecular gas mass of M_H2 < 2.5 x 10^10 Msun, assuming a velocity width of 200
km s^{-1} and a CO-to-H2 conversion factor of alpha_CO=0.8 Msun (K km s^{-1}
pc^{-2})^{-1}. The ratio of L_FIR/L'CO, a measure of star formation efficiency
(SFE), is comparable to or higher than the two z ~ 1.5 sBzKs detected in
CO(2-1) previously, suggesting that sBzKs can have a wide range of SFEs.
Comparisons of far-infrared luminosity, gas mass, and stellar mass among the
sBzKs suggest that SDF-26821 is at an earlier stage of forming stars with a
similar SFE and/or more efficiently forming stars than the two z ~ 1.5 sBzKs.
The higher SFEs and specific star formation rates of the sBzKs compared to
local spirals are indicative of the difference in star formation modes between
these systems, suggesting that sBzKs are not just scaled-up versions of local
spirals.Comment: 4 pages, 4 figures, Accepted for publication in PAS
Distortion of Magnetic Fields in a Starless Core V: Near-infrared and Submillimeter Polarization in FeSt 1-457
The relationship between submillimeter (submm) dust emission polarization and
near-infrared (NIR) -band polarization produced by dust dichroic extinction
was studied for the cold starless dense core FeSt 1-457. The distribution of
polarization angles (-rotated for submm) and degrees were found to
be very different between at submm and NIR wavelengths. The mean polarization
angles for FeSt 1-457 at submm and NIR wavelengths are and , respectively. The correlation
between and was found to be linear from outermost regions to
relatively dense line of sight of mag, indicating that NIR
polarization reflects overall polarization (magnetic field) structure of the
core at least in this density range. The flat versus
correlations were confirmed, and the polarization efficiency was found to be
comparable to the observational upper limit (Jones 1989). On the other hand, as
reported by Alves et al., submm polarization degrees show clear linearly
decreasing trend against from mag to the densest center
( mag), appearing as "polarization hole" structure. The power
law index for the versus relationship was obtained to be
, indicating that the alignment for the submm sensitive dust is
lost. These very different polarization distributions at submm and NIR
wavelengths suggest that (1) there is different radiation environment at these
wavelengths or (2) submm-sensitive dust is localized or the combination of
them.Comment: Accepted to the Astrophysical Journal (ApJ
Renoprotective Action of a Matrix Metalloproteinase Inhibitor in Progressive Mesangioproliferative Nephritis
Background/Aim: Matrix metalloproteinases (MMPs) play pivotal roles in extracellular matrix turnover and are involved in chronic kidney disease. The renoprotective action of a synthetic MMP inhibitor, compound A, was investigated in chronic nephritis. Methods: Nephritis was induced by a single injection of anti-Thy1.1 antibody to unilaterally nephrectomized rats. The effects of compound A on proteinuria, blood urea nitrogen, and matrix-related gene expressions were evaluated. Collagen accumulation, as assessed by periodic acid-Schiff staining and hydroxyproline content, was determined. The integrity of glomerular epithelial cells and glomerular basement membrane was evaluated with desmin immunohistochemistry and electron microscopic detection of anionic charge sites, respectively. Results: Treatment with compound A notably attenuated proteinuria, ameliorated blood urea nitrogen, and prevented glomerulosclerosis. Gene upregulation of collagen and transforming growth factor β1 in the cortex was prevented in the treated animals. Glomerular epithelial cell injury was milder, and glomerular basement membrane anionic sites were protected with the treatment. Conclusion: A novel MMP inhibitor, compound A, exerts protective effects in progressive glomerulonephritis. Compound A ameliorates various aspects of renal injuries and may have therapeutic potential toward kidney diseases
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