95 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
Revisited cold gas content with atomic carbon [C I] in z=2.5 protocluster galaxies
We revisit the cold gas contents of galaxies in a protocluster at z=2.49
using the lowest neutral atomic carbon transition [CI]P-P from
Atacama Large Millimeter/submillimeter Array observations. We aim to test if
the same gas mass calibration applied in field galaxies can be applied to
protocluster galaxies. Five galaxies out of sixteen targeted galaxies are
detected in the [CI] line, and these are all previously detected in CO(3-2) and
CO(4-3) and three in 1.1 mm dust continuum. We investigate the line luminosity
relations between CO and [CI] in the protocluster and compare them with other
previous studies. We then compare the gas mass based on three gas tracers of
[CI], CO(3-2), and dust if at least one of the last two tracers are available.
Using the calibration adopted for field main-sequence galaxies, the [CI]-based
gas measurements are lower than or comparable to the CO-based gas measurements
by -0.35 dex at the lowest with the mean deviation of -0.14 dex. The
differences between [CI]- and the dust- based measurements are relatively mild
by up to 0.16 dex with the mean difference of 0.02 dex. Taking these all
together with calibration uncertainties, with the [CI] line, we reconfirm our
previous findings that the mean gas fraction is comparable to field galaxies
for a stellar-mass range of .
However, at least for these secure five detections, the depletion time scale
decreases more rapidly with stellar mass than field galaxies that might be
related to earlier quenching in dense environments.Comment: accepted for publication in Ap
Chondroitin Sulfate Iron Colloid-Enhanced MR Imaging in Patients with Small Hepatocellular Carcinomas: Correlations with Hemodynamic and Pathologic Examinations
To determine the usefulness of chondroitin sulfate iron colloid (CSIC)-enhanced magnetic resonance imaging (MRI) in evaluation of the histologic grade of hepatocellular carcinoma (HCC), we performed a comparative study with computed tomography during arterial portography (CTAP) and CT arteriography. Twenty-one surgically resected HCCs 3 cm or less in diameter were examined. There were five well- differentiated, six well- to moderately-differentiated and ten moderately- or poorly-differentiated HCCs. T2-weighted spin echo images (repetition time: 2,000 ms, echo time: 90 ms) were taken before and after intravenous injection of 23.6 ?mol Fe/kg of CSIC. The differences between precontrast and postcontrast contrast-to-noise ratios (enhancement index) was correlated with the findings of CTAP, CT arteriography and histological examination. The enhancement index increased with statistical significance as the intranodular arterial perfusion increased (P < 0.01), and as the intranodular portal perfusion decreased (P < 0.01). Though the enhancement index tended to increase as the grade of malignancy increased, no statistical significance was found. CSIC-enhanced MRI allowed a noninvasive evaluation of the intranodular reticuloendothelial function. We consider this procedure as a supplementary method for evaluation of the histologic grade of HCC prior to performing invasive procedures such as angiography and biopsy
A prospective follow-up study of the association of radiation exposure with fatal and non-fatal stroke among atomic bomb survivors in Hiroshima and Nagasaki (1980–2003)
SXDF-ALMA 2 Arcmin^2 Deep Survey: Resolving and Characterizing the Infrared Extragalactic Background Light Down to 0.5 mJy
We present a multi-wavelength analysis of five submillimeter sources (S_1.1mm
= 0.54-2.02 mJy) that were detected during our 1.1-mm-deep continuum survey in
the SXDF-UDS-CANDELS field (2 arcmin^2, 1sigma = 0.055 mJy beam^-1) using the
Atacama Large Millimeter/submillimeter Array (ALMA). The two brightest sources
correspond to a known single-dish (AzTEC) selected bright submillimeter galaxy
(SMG), whereas the remaining three are faint SMGs newly uncovered by ALMA. If
we exclude the two brightest sources, the contribution of the ALMA-detected
faint SMGs to the infrared extragalactic background light is estimated to be ~
4.1^{+5.4}_{-3.0} Jy deg^{-2}, which corresponds to ~ 16^{+22}_{-12}% of the
infrared extragalactic background light. This suggests that their contribution
to the infrared extragalactic background light is as large as that of bright
SMGs. We identified multi-wavelength counterparts of the five ALMA sources. One
of the sources (SXDF-ALMA3) is extremely faint in the optical to near-infrared
region despite its infrared luminosity (L_IR ~ 1e12 L_sun or SFR ~ 100 M_sun
yr^{-1}). By fitting the spectral energy distributions (SEDs) at the
optical-to-near-infrared wavelengths of the remaining four ALMA sources, we
obtained the photometric redshifts (z_photo) and stellar masses (M_*): z_photo
~ 1.3-2.5, M_* ~ (3.5-9.5)e10 M_sun. We also derived their star formation rates
(SFRs) and specific SFRs (sSFRs) as ~ 30-200 M_sun yr^{-1} and ~ 0.8-2
Gyr^{-1}, respectively. These values imply that they are main-sequence
star-forming galaxies.Comment: PASJ accepted, 15 pages, 6 figures, 2 table
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