6,628 research outputs found
The Spitzer South Pole Telescope Deep Field Survey: Linking galaxies and halos at z=1.5
We present an analysis of the clustering of high-redshift galaxies in the
recently completed 94 deg Spitzer-SPT Deep Field survey. Applying flux and
color cuts to the mid-infrared photometry efficiently selects galaxies at
in the stellar mass range , making this
sample the largest used so far to study such a distant population. We measure
the angular correlation function in different flux-limited samples at scales
(corresponding to physical distances Mpc) and
thereby map the one- and two-halo contributions to the clustering. We fit halo
occupation distributions and determine how the central galaxy's stellar mass
and satellite occupation depend on the halo mass. We measure a prominent peak
in the stellar-to-halo mass ratio at a halo mass of , 4.5 times higher than the value. This supports
the idea of an evolving mass threshold above which star formation is quenched.
We estimate the large-scale bias in the range and the satellite
fraction to be , showing a clear evolution compared to
. We also find that, above a given stellar mass limit, the fraction of
galaxies that are in similar mass pairs is higher at than at . In
addition, we measure that this fraction mildly increases with the stellar mass
limit at , which is the opposite of the behavior seen at low-redshift.Comment: 32 pages, 22 figures. Published in MNRA
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Phase I dose-escalation trial of the oral AKT inhibitor uprosertib in combination with the oral MEK1/MEK2 inhibitor trametinib in patients with solid tumors.
PurposeThis study aimed to determine the safety, tolerability, and recommended phase II doses of trametinib plus uprosertib (GSK2141795) in patients with solid tumors likely to be sensitive to MEK and/or AKT inhibition.MethodsThis was a phase I, open-label, dose-escalation, and dose-expansion study in patients with triple-negative breast cancer or BRAF-wild type advanced melanoma. The primary outcome of the expansion study was investigator-assessed response. Among 126 enrolled patients, 63 received continuous oral daily dosing of trametinib and uprosertib, 29 received various alternative dosing schedules, and 34 were enrolled into expansion cohorts. Doses tested in the expansion cohort were trametinib 1.5 mg once daily (QD) + uprosertib 50 mg QD.ResultsAdverse events (AEs) were consistent with those reported in monotherapy studies but occurred at lower doses and with greater severity. Diarrhea was the most common dose-limiting toxicity; diarrhea and rash were particularly difficult to tolerate. Overall, 59% and 6% of patients reported AEs with a maximum severity of grade 3 and 4, respectively. Poor tolerability prevented adequate delivery of uprosertib with trametinib at a concentration predicted to have clinical activity. The study was terminated early based on futility in the continuous-dosing expansion cohorts and a lack of pharmacological or therapeutic advantage with intermittent dosing. The objective response rate was < 5% (1 complete response, 5 partial responses).ConclusionsContinuous and intermittent dosing of trametinib in combination with uprosertib was not tolerated, and minimal clinical activity was observed in all schedules tested
CaloMan: Fast generation of calorimeter showers with density estimation on learned manifolds
Precision measurements and new physics searches at the Large Hadron Collider
require efficient simulations of particle propagation and interactions within
the detectors. The most computationally expensive simulations involve
calorimeter showers. Advances in deep generative modelling - particularly in
the realm of high-dimensional data - have opened the possibility of generating
realistic calorimeter showers orders of magnitude more quickly than
physics-based simulation. However, the high-dimensional representation of
showers belies the relative simplicity and structure of the underlying physical
laws. This phenomenon is yet another example of the manifold hypothesis from
machine learning, which states that high-dimensional data is supported on
low-dimensional manifolds. We thus propose modelling calorimeter showers first
by learning their manifold structure, and then estimating the density of data
across this manifold. Learning manifold structure reduces the dimensionality of
the data, which enables fast training and generation when compared with
competing methods.Comment: Accepted to the Machine Learning and the Physical Sciences Workshop
at NeurIPS 202
The Clustering of Extremely Red Objects
We measure the clustering of Extremely Red Objects (EROs) in ~8 deg^2 of the
NOAO Deep Wide Field Survey Bo\"otes field in order to establish robust links
between ERO z~1.2 and local galaxy z<0.1 populations. Three different color
selection criteria from the literature are analyzed to assess the consequences
of using different criteria for selecting EROs. Specifically, our samples are
(R-K_s)>5.0 (28,724 galaxies), (I-K_s)>4.0 (22,451 galaxies) and (I-[3.6])>5.0
(64,370 galaxies). Magnitude-limited samples show the correlation length (r_0)
to increase for more luminous EROs, implying a correlation with stellar mass.
We can separate star-forming and passive ERO populations using the (K_s-[24])
and ([3.6]-[24]) colors to K_s=18.4 and [3.6]=17.5, respectively. Star-forming
and passive EROs in magnitude limited samples have different clustering
properties and host dark halo masses, and cannot be simply understood as a
single population. Based on the clustering, we find that bright passive EROs
are the likely progenitors of >4L^* elliptical galaxies. Bright EROs with
ongoing star formation were found to occupy denser environments than
star-forming galaxies in the local Universe, making these the likely
progenitors of >L^* local ellipticals. This suggests that the progenitors of
massive >4L^* local ellipticals had stopped forming stars by z>1.2, but that
the progenitors of less massive ellipticals (down to L^*) can still show
significant star formation at this epoch.Comment: 19 pages, 16 figures, 4 tables, Accepted to ApJ 27th November 201
Multiaperture Photometry of Galaxies in the Coma Cluster
We present a set of photometry for 745 band selected
objects in a region centered on the core of the Coma
cluster. This includes 516 galaxies and is at least 80% complete to H=16, with
a spectroscopically complete sample of 111 cluster members (nearly all with
morphological classification) for . For each object we present total
\cite{kron80} magnitudes and aperture photometry. As an example, we use these
data to derive color-magnitude relations for Coma early-type galaxies, measure
the intrinsic scatter of these relations and its dependence on galaxy mass, and
address the issue of color gradients. We find that the color gradients are mild
and that the intrinsic scatter about the color-magnitude relation is small
( mag in and less than in , or ).
There is no evidence that the intrinsic scatter varies with galaxy luminosity,
suggesting that the cluster red sequence is established at early epochs over a
range of in stellar mass.Comment: 41 pages, 5 figures, 18 data tables attached to source files or
available on request from R. De propris. Accepted for publication in
Astrophysical Journal Supplement Serie
RCS2 J232727.6-020437: An Efficient Cosmic Telescope at
We present a detailed gravitational lens model of the galaxy cluster RCS2
J232727.6-020437. Due to cosmological dimming of cluster members and ICL, its
high redshift () makes it ideal for studying background galaxies.
Using new ACS and WFC3/IR HST data, we identify 16 multiple images. From
MOSFIRE follow up, we identify a strong emission line in the spectrum of one
multiple image, likely confirming the redshift of that system to .
With a highly magnified () source plane area of
arcmin at , RCS2 J232727.6-020437 has a lensing efficiency comparable
to the Hubble Frontier Fields clusters. We discover four highly magnified
candidate Lyman-break galaxies behind the cluster, one of which may be
multiply-imaged. Correcting for magnification, we find that all four galaxies
are fainter than . One candidate is detected at in
both Spitzer/IRAC [3.6] and [4.5] channels. A spectroscopic follow-up with
MOSFIRE does not result in the detection of the Lyman-alpha emission line from
any of the four candidates. From the MOSFIRE spectra we place median upper
limits on the Lyman-alpha flux of ().Comment: 14 pages, 9 figures, submitted to ApJ on 3/06/201
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