696 research outputs found
Environmental dependence of 8um luminosity functions of galaxies at z~0.8: Comparison between RXJ1716.4+6708 and the AKARI NEP deep field
We aim to reveal environmental dependence of infrared luminosity functions
(IR LFs) of galaxies at z~0.8 using the AKARI satellite. We construct restframe
8um IR LFs in the cluster region RXJ1716.4+6708 at z=0.81, and compare them
with a blank field using the AKARI North Ecliptic Pole deep field data at the
same redshift. AKARI's wide field of view (10'x10') is suitable to investigate
wide range of galaxy environments. AKARI's 15um filter is advantageous here
since it directly probes restframe 8um at z~0.8, without relying on a large
extrapolation based on a SED fit, which was the largest uncertainty in previous
work. We have found that cluster IR LFs at restframe 8um have a factor of 2.4
smaller L^* and a steeper faint-end slope than that of the field. Confirming
this trend, we also found that faint-end slopes of the cluster LFs becomes
flatter and flatter with decreasing local galaxy density. These changes in LFs
cannot be explained by a simple infall of field galaxy population into a
cluster. Physics that can preferentially suppress IR luminous galaxies in high
density regions is required to explain the observed results.Comment: Accepted for publication in A&A AKARI special issu
Environmental dependence of 8 μm luminosity functions of galaxies at z ~ 0.8: Comparison between RXJ1716.4+6708 and the AKARI NEP-deep field
Aims. We aim to reveal environmental dependence of infrared luminosity functions (IR LFs) of galaxies at z ~ 0.8 using the AKARI
satellite. AKARI’s wide field of view and unique mid-IR filters help us to construct restframe 8 μm LFs directly without relying on
SED models.
Methods. We construct restframe 8 μm IR LFs in the cluster region RXJ1716.4+6708 at z = 0.81, and compare them with a blank
field using the AKARI north ecliptic pole deep field data at the same redshift. AKARI’s wide field of view (10' × 10') is suitable to
investigate wide range of galaxy environments. AKARI’s 15 μm filter is advantageous here since it directly probes restframe 8 μm at
z ~ 0.8, without relying on a large extrapolation based on a SED fit, which was the largest uncertainty in previous work.
Results. We have found that cluster IR LFs at restframe 8 μm have a factor of 2.4 smaller L^∗ and a steeper faint-end slope than that
of the field. Confirming this trend, we also found that faint-end slopes of the cluster LFs becomes flatter and flatter with decreasing
local galaxy density. These changes in LFs cannot be explained by a simple infall of field galaxy population into a cluster. Physics
that can preferentially suppress IR luminous galaxies in high density regions is required to explain the observed results
Developing a High Resolution ZDC for the EIC
The Electron Ion Collider offers the opportunity to make un-paralleled multidimen- sional measurements of the spin structure of the proton and nuclei, as well as a study of the onset of partonic saturation at small Bjorken-x [1]. An important requirement of the physics program is the tagging of spectator neutrons and the identification of forward photons. We propose to design and build a Zero Degree Calorimeter, or ZDC, to measure photons and neutrons with excellent energy & position resolution
Colossal magnetocapacitance and scale-invariant dielectric response in phase-separated manganites
Thin films of strongly-correlated electron materials (SCEM) are often grown
epitaxially on planar substrates and typically have anisotropic properties that
are usually not captured by edge-mounted four-terminal electrical measurements,
which are primarily sensitive to in-plane conduction paths. Accordingly, the
correlated interactions in the out-of-plane (perpendicular) direction cannot be
measured but only inferred. We address this shortcoming and show here an
experimental technique in which the SCEM under study, in our case a 600
Angstrom-thick (La1-yPry)0.67Ca0.33MnO3 (LPCMO) film, serves as the base
electrode in a metal-insulator-metal (MIM) trilayer capacitor structure. This
unconventional arrangement allows for simultaneous determination of colossal
magnetoresistance (CMR) associated with dc transport parallel to the film
substrate and colossal magnetocapacitance (CMC) associated with ac transport in
the perpendicular direction. We distinguish two distinct strain-related
direction-dependent insulator-metal (IM) transitions and use Cole-Cole plots to
establish a heretofore unobserved collapse of the dielectric response onto a
universal scale-invariant power-law dependence over a large range of frequency,
temperature and magnetic field.Comment: 32 pages, 4 figures, Supplementary section included, Submitted to
Nature Physic
Transcriptional Regulation of an Evolutionary Conserved Intergenic Region of CDT2-INTS7
In the mammalian genome, a substantial number of gene pairs (approximately 10%) are arranged head-to-head on opposite strands within 1,000 base pairs, and separated by a bidirectional promoter(s) that generally drives the co-expression of both genes and results in functional coupling. The significance of unique genomic configuration remains elusive.Here we report on the identification of an intergenic region of non-homologous genes, CDT2, a regulator of DNA replication, and an integrator complex subunit 7 (INTS7), an interactor of the largest subunit of RNA polymerase II. The CDT2-INTS7 intergenic region is 246 and 245 base pairs long in human and mouse respectively and is evolutionary well-conserved among several mammalian species. By measuring the luciferase activity in A549 cells, the intergenic human sequence was shown to be able to drive the reporter gene expression in either direction and notably, among transcription factors E2F, E2F1 approximately E2F4, but not E2F5 and E2F6, this sequence clearly up-regulated the reporter gene expression exclusively in the direction of the CDT2 gene. In contrast, B-Myb, c-Myb, and p53 down-regulated the reporter gene expression in the transcriptional direction of the INTS7 gene. Overexpression of E2F1 by adenoviral-mediated gene transfer resulted in an increased CDT2, but not INTS7, mRNA level. Real-time polymerase transcription (RT-PCR) analyses of the expression pattern for CDT2 and INTS7 mRNA in human adult and fetal tissues and cell lines revealed that transcription of these two genes are asymmetrically regulated. Moreover, the abundance of mRNA between mouse and rat tissues was similar, but these patterns were quite different from the results obtained from human tissues.These findings add a unique example and help to understand the mechanistic insights into the regulation of gene expression through an evolutionary conserved intergenic region of the mammalian genome
Transverse single-spin asymmetry for very forward neutral pion production in polarized collisions at GeV
Transverse single-spin asymmetries of very forward neutral pions generated in
polarized collisions allow us to understand the production mechanism in
terms of perturbative and non-perturbative strong interactions. During 2017 the
RHICf Collaboration installed an electromagnetic calorimeter in the zero-degree
region of the STAR detector at the Relativistic Heavy Ion Collider (RHIC) and
measured neutral pions produced at pseudorapidity larger than 6 in polarized
+ collisions at = 510 GeV. The large non-zero asymmetries
increasing both in longitudinal momentum fraction and transverse
momentum have been observed at low transverse momentum
GeV/ for the first time at this collision energy. The asymmetries show an
approximate scaling in the region where non-perturbative
processes are expected to dominate. A non-negligible contribution from soft
processes may be necessary to explain the nonzero neutral pion asymmetries.Comment: This paper submitted to PRL is the final result of arXiv:1902.0785
Orbital characterization of GJ1108A system, and comparison of dynamical mass with model-derived mass for resolved binaries
We report an orbital characterization of GJ1108Aab that is a low-mass binary
system in pre-main-sequence phase. Via the combination of astrometry using
adaptive optics and radial velocity measurements, an eccentric orbital solution
of =0.63 is obtained, which might be induced by the Kozai-Lidov mechanism
with a widely separated GJ1108B system. Combined with several observed
properties, we confirm the system is indeed young. Columba is the most probable
moving group, to which the GJ1108A system belongs, although its membership to
the group has not been established. If the age of Columba is assumed for
GJ1108A, the dynamical masses of both GJ1108Aa and GJ1108Ab ( and ) are more massive than what an
evolutionary model predicts based on the age and luminosities. We consider the
discrepancy in mass comparison can attribute to an age uncertainty; the system
is likely older than stars in Columba, and effects that are not implemented in
classical models such as accretion history and magnetic activity are not
preferred to explain the mass discrepancy. We also discuss the performance of
the evolutionary model by compiling similar low-mass objects in evolutionary
state based on the literature. Consequently, it is suggested that the current
model on average reproduces the mass of resolved low-mass binaries without any
significant offsets.Comment: Accepted in Ap
Exceptionally high incidence of symptomatic grade 2–5 radiation pneumonitis after stereotactic radiation therapy for lung tumors
<p>Abstract</p> <p>Background</p> <p>To determine the usefulness of dose volume histogram (DVH) factors for predicting the occurrence of radiation pneumonitis (RP) after application of stereotactic radiation therapy (SRT) for lung tumors, DVH factors were measured before irradiation.</p> <p>Methods</p> <p>From May 2004 to April 2006, 25 patients were treated with SRT at the University of Tokyo Hospital. Eighteen patients had primary lung cancer and seven had metastatic lung cancer. SRT was given in 6–7 fields with an isocenter dose of 48 Gy in four fractions over 5–8 days by linear accelerator.</p> <p>Results</p> <p>Seven of the 25 patients suffered from RP of symptomatic grade 2–5 according to the NCI-CTC version 3.0. The overall incidence rate of RP grade2 or more was 29% at 18 months after completing SRT and three patients died from RP. RP occurred at significantly increased frequencies in patients with higher conformity index (CI) (p = 0.0394). Mean lung dose (MLD) showed a significant correlation with V<sub>5</sub>–V<sub>20 </sub>(irradiated lung volume) (p < 0.001) but showed no correlation with CI. RP did not statistically correlate with MLD. MLD had the strongest correlation with V<sub>5</sub>.</p> <p>Conclusion</p> <p>Even in SRT, when large volumes of lung parenchyma are irradiated to such high doses as the minimum dose within planning target volume, the incidence of lung toxicity can become high.</p
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