8,598 research outputs found
The Core Mass Function in the Massive Protocluster G286.21+0.17 revealed by ALMA
We study the core mass function (CMF) of the massive protocluster
G286.21+0.17 with the Atacama Large Millimeter/submillimeter Array via 1.3~mm
continuum emission at a resolution of 1.0\arcsec\ (2500~au). We have mapped a
field of 5.3\arcmin5.3\arcmin\ centered on the protocluster clump. We
measure the CMF in the central region, exploring various core detection
algorithms, which give source numbers ranging from 60 to 125, depending on
parameter selection. We estimate completeness corrections due to imperfect flux
recovery and core identification via artificial core insertion experiments. For
masses , the fiducial dendrogram-identified CMF can be fit
with a power law of the form
with , slightly shallower than, but still consistent with, the
index of the Salpeter stellar initial mass function of 1.35.
Clumpfind-identified CMFs are significantly shallower with
. While raw CMFs show a peak near ,
completeness-corrected CMFs are consistent with a single power law extending
down to , with only a tentative indication of a shallowing
of the slope around . We discuss the implications of these
results for star and star cluster formation theories.Comment: 11 pages, accepted by Ap
Dibromido{2-hydroxy-N′-[phenyl(2-pyridyl)methylene]benzohydrazide}copper(II)
In the title complex, [CuBr2(C19H15N3O2)], the metal ion is coordinated by the N,N′,O-tridentate 2-hydroxy-N′-[phenyl(2-pyridyl)methylene]benzohydrazide ligand and two bromide ions, resulting in a distorted CuN2OBr2 square-based pyramidal coordination geometry with one bromide ion in the apical site. An intramolecular N—H⋯O hydrogen bond occurs in the ligand. In the crystal, molecules are connected by intermolecular C—H⋯O, C—H⋯Br and O—H⋯Br interactions
Parallel Excitatory and Inhibitory Neural Circuit Pathways Underlie Reward-Based Phasic Neural Responses
Phasic activity of dopaminergic (DA) neurons in the ventral tegmental area or substantia nigra compacta (VTA/SNc) has been suggested to encode reward-prediction error signal for reinforcement learning. Recent studies have shown that the lateral habenula (LHb) neurons exhibit a similar response, but for nonrewarding or punishment signals. Hence, the transient signaling role of LHb neurons is opposite that of DA neurons and also that of several other brain nuclei such as the border region of the globus pallidus internal segment (GPb) and the rostral medial tegmentum (RMTg). Previous theoretical models have investigated the neural circuit mechanism underlying reward-based phasic activity of DA neurons, but the feasibility of a larger neural circuit model to account for the observed reward-based phasic activity in other brain nuclei such as the LHb has yet to be shown. Here, we propose a large-scale neural circuit model and show that parallel excitatory and inhibitory pathways underlie the learned neural responses across multiple brain regions. Specifically, the model can account for the phasic neural activity observed in the GPb, LHb, RMTg, and VTA/SNc. Based on sensitivity analysis, the model is found to be robust against changes in the overall neural connectivity strength. The model also predicts that striosomes play a key role in the phasic activity of VTA/SNc and LHb neurons by encoding previous and expected rewards. Taken together, our model identifies the important role of parallel neural circuit pathways in accounting for phasic activity across multiple brain areas during reward and punishment processing
Bis(dicyanamido-κN 1)bis[2-(2-hydroxyethyl)pyridine-κ2 N,O]nickel(II)
In the title complex, [Ni{N(CN)2}2(C7H9NO)2], the NiII ion (site symmetry ) adopts a distorted trans-NiO2N4 octahedral geometry. In the crystal, intermolecular O—H⋯N hydrogen bonds link the molecules, forming a chain along the c axis
ESO Imaging Survey: Infrared Deep Public Survey
This paper presents new J and Ks data obtained from observations conducted at
the ESO 3.5m New Technology Telescope using the SOFI camera. These data were
taken as part of the ESO Imaging Survey Deep Public Survey (DPS) and
significantly extend the earlier optical/infrared EIS-DEEP survey presented in
a previous paper. The DPS-IR survey comprises two observing strategies: shallow
Ks observations providing nearly full coverage of pointings with complementary
multi-band optical data and deeper J and Ks observations of the central parts
of these fields. The DPS-IR survey provides a coverage of roughly 2.1 square
degrees in Ks with 0.63 square degrees to fainter magnitudes and also covered
in J, over three independent regions of the sky. The goal of the present paper
is to describe the observations, the data reduction procedures, and to present
the final survey products. The astrometric solution with an estimated accuracy
of <0.15" is based on the USNO catalog. The final stacked images presented here
number 89 and 272, in J and Ks, respectively, the latter reflecting the larger
surveyed area. The J and Ks images were taken with a median seeing of 0.77" and
0.8". The images reach a median 5sigma limiting magnitude of J_AB~23.06 in an
aperture of 2", while the corresponding limiting magnitude in Ks_AB is ~21.41
and ~22.16 mag for the shallow and deep strategies. Overall, the observed
limiting magnitudes are consistent with those originally proposed. The quality
of the data has been assessed by comparing the measured magnitude of sources at
the bright end directly with those reported by the 2MASS survey and at the
faint end by comparing the counts of galaxies and stars with those of other
surveys to comparable depth and to model predictions. The final science-grade
catalogs and images are available at CDS.Comment: Accepted for publication in A&A, 14 pages, 8 figures, a full
resolution version of the paper is available from
http://www.astro.ku.dk/~lisbeth/eisdata/papers/5019.pd
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