Abstract
Star cluster formation in the early universe and its contribution to reionization remains largely unconstrained to date. Here we present JWST/NIRCam imaging of the most highly magnified ...galaxy known at
z
∼ 6, the
Sunrise
arc. We identify six young massive star clusters (YMCs) with measured radii spanning from ∼20 down to ∼1 pc (corrected for lensing magnification), estimated stellar masses of ∼10
6–7
M
⊙
, and ages of 1–30 Myr based on SED fitting to photometry measured in eight filters extending to rest frame 7000 Å. The resulting stellar mass surface densities are higher than 1000
M
⊙
pc
−2
(up to a few 10
5
M
⊙
pc
−2
), and their inferred dynamical ages qualify the majority of these systems as gravitationally bound stellar clusters. The star cluster ages map the progression of star formation along the arc, with two evolved systems (≳10 Myr old) followed by very young clusters. The youngest stellar clusters (<5 Myr) show evidence of prominent H
β
+O
iii
emission based on photometry with equivalent widths larger than >1000 Å rest frame and are hosted in a 200 pc sized star-forming complex. Such a region dominates the ionizing photon production with a high efficiency
log
(
ξ
ion
Hz
erg
−
1
)
∼
25.7
. A significant fraction of the recently formed stellar mass of the galaxy (10%–30%) occurred in these YMCs. We speculate that such sources of ionizing radiation boost the ionizing photon production efficiency, which eventually carves ionized channels that might favor the escape of Lyman continuum radiation. The survival of some of the clusters would make them the progenitors of massive and relatively metal-poor globular clusters in the local universe.
We investigate the relation between star formation rate (SFR) and stellar mass (\(M_*\)) in sub-galactic (\(\sim 1\)kpc) scale of 93 local (\(0.01<z<0.02\)) massive (\(M_*>10^{10.5}M_{\odot}\)) ...spiral galaxies. To derive spatially-resolved SFR and stellar mass, we perform so-called pixel-to-pixel SED fitting, which fits an observed spatially-resolved multiband SED with a library of model SEDs using Bayesian statistics approach. We use 2 bands (FUV and NUV) and 5 bands (\(u\), \(g\), \(r\), \(i\), and \(z\)) imaging data from Galaxy Evolution Explorer (GALEX) and Sloan Digital Sky Survey (SDSS), respectively. We find a tight nearly linear relation between the local surface density of SFR (\(\Sigma_{\rm{SFR}}\)) and stellar mass (\(\Sigma_{*}\)) which has flattening in high \(\Sigma_{*}\). The near linear relation between \(\Sigma_{*}\) and \(\Sigma_{\rm SFR}\) suggests constant sSFR throughout the galaxies, and the scatter of the relation is directly related to that of sSFR. Therefore, we analyse the variation of sSFR in various scales. More massive galaxies on average have lower sSFR throughout them than less massive galaxies. We also find that barred galaxies have lower sSFR in a core region than non-barred galaxies. However, in the outside region, sSFR of barred and non-barred galaxies are similar and lead to the similar total sSFR.
Abstract
We present new observations of MRG-M2129, a quiescent galaxy at
z
= 2.15, with the Atacama Large Millimeter/submillimeter Array (ALMA). With the combination of the effect of gravitational ...lensing by the foreground galaxy cluster and the angular resolution provided by ALMA, our data reveal 1.2 mm continuum emission at ∼130 pc angular resolution. Compact dust continuum is detected at 7.9
σ
in the target but displaced from its stellar peak position by 62 ± 38 mas, or ∼169 ± 105 pc in the source plane. We find a considerably high dust-to-stellar mass ratio, 4 × 10
−4
. From nondetection of the C
i
3
P
2
→
3
P
1
line, we derive 3
σ
upper limits on the molecular gas-to-dust mass ratio
δ
GDR
< 60 and the molecular gas-to-stellar mass ratio
f
H2
< 2.3%. The derived
δ
GDR
is ≳2× smaller than the typical value assumed for quiescent galaxies in the literature. Our study supports the idea that there exists a broad range of
δ
GDR
and urges submillimeter follow-up observations of quenching/recently quenched galaxies at similar redshifts. Based on the inferred low
δ
GDR
and other observed properties, we argue that the central black hole is still active and regulates star formation in the system. Our study exhibits a rare case of a gravitationally lensed type 2 QSO harbored by a quiescent galaxy.
Double well potential (DWP) plays an important role in quantum physics but its analytical exact solutions are incomplete, except for some limited quasi-exact solvable (QES) and therefore numerical ...solutions are still required. This paper is aimed to obtain numerical solution of the recently proposed symnetric-hyperbolicus DWP and by using our newly developed filter method. The filter method is able to produce eigen-energies and eigenfunctions those are in accordance with the exact analytical results. Next, we obtain the dependence of the ground state energy and the energy separation between the 2 lowest states on the DWP parameter k. For large k, the 2 lowest energy levels are below the potential barrier so the eigenfunctions penetrate the barrier, so the 2 lowest energy levels can be considered as the result of a single energy split. In this case, we observe that the energy separation is an exponential function k, as opposed to a linear function for smaller k in the non tunelling region. The exponential trend of the numerical results is in good agreement with the theoretical approach and allows one to estimate the 2 lowest energies for a given k.
HIGHLIGHTS
For small , the two lowest energy levels lie above the barrier potential, where both ground state and the energy separation is a linier function of
For large , the two lowest energy levels lie below the barrier potential so that the eigenfunction penetrates the barrier. As a result, the two lowest energy levels can be thought of as splitting energy states. In this case, we observe that the energy separation is an exponential function . Since also depends on , it is possible to estimate the two lowest energy levels
The exponential trend of the numerical results for large agrees well with the theoretical approach, shown by the linear relationship between and the classical actions in the classical forbidden regions,
GRAPHICAL ABSTRACT
Abstract
The gravitationally lensed star WHL 0137–LS, nicknamed Earendel, was identified with a photometric redshift
z
phot
= 6.2 ± 0.1 based on images taken with the Hubble Space Telescope. Here we ...present James Webb Space Telescope (JWST) Near Infrared Camera images of Earendel in eight filters spanning 0.8–5.0
μ
m. In these higher-resolution images, Earendel remains a single unresolved point source on the lensing critical curve, increasing the lower limit on the lensing magnification to
μ
> 4000 and restricting the source plane radius further to
r
< 0.02 pc, or ∼4000 au. These new observations strengthen the conclusion that Earendel is best explained by an individual star or multiple star system and support the previous photometric redshift estimate. Fitting grids of stellar spectra to our photometry yields a stellar temperature of
T
eff
≃ 13,000–16,000 K, assuming the light is dominated by a single star. The delensed bolometric luminosity in this case ranges from
log
(
L
)
=
5.8
to 6.6
L
⊙
, which is in the range where one expects luminous blue variable stars. Follow-up observations, including JWST NIRSpec scheduled for late 2022, are needed to further unravel the nature of this object, which presents a unique opportunity to study massive stars in the first billion years of the universe.
Our recent developed filter method (Phys. Rev E 96(3), 033302, 2017) is applied here to investigate the energy spectrum and their corresponding wave function of one dimensional crystal. The periodic ...one dimensional potential is modelled by using one dimensional periodic harmonic oscillator, with variation on oscillator potential depth, quasi-potential depth, and crystal width. For energy less than the potential depth of the oscillator, the computational results reveal that the periodic harmonic oscillator produces a discrete spectrum, as the energy spectrum of a single harmonic potential. However, for energy almost equal to or greater than the depth of the potential oscillator, the periodic harmonic oscillator demonstrates the existence of pattern similar to energy band in crystal.
We present a multiwavelength study of IC 860, a nearby post-starburst galaxy at the early stage of transitioning from blue and star forming to red and quiescent. Optical images reveal a galaxy-wide, ...dusty outflow originating from a compact core. We find evidence for a multiphase outflow in the molecular and neutral gas phase from the CO position-velocity diagram and NaD absorption features. We constrain the neutral mass outflow rate to be ∼0.5 M ⊙ yr−1, and the total hydrogen mass outflow rate to be ∼12 M ⊙ yr−1. Neither outflow component seems able to escape the galaxy. We also find evidence for a recent merger in the optical images, CO spatial distribution, and kinematics, and evidence for a buried active galactic nucleus in the optical emission line ratios, mid-IR properties, and radio spectral shape. The depletion time of the molecular gas reservoir under the current star formation rate is ∼7 Gyr, indicating that the galaxy could stay at the intermediate stage between the blue and red sequence for a long time. Thus the timescales for a significant decline in star formation rate (quenching) and gas depletion are not necessarily the same. Our analysis supports the quenching picture where outflows help suppress star formation by disturbing rather than expelling the gas and shed light on possible ongoing activities in similar quenching galaxies.
One of the important things that must be considered by the hospital is patient safety, where patient safety can be improved by implementing a patient safety culture, so that the patient safety ...culture goes well, it is necessary to increase the role of the leader. This study aims to determine whether there is a relationship between the role of a leader and the implementation of patient safety culture. Method: this research is a quantitative study using cross sectional. Data were collected using a questionnaire of 118 nurses using a total population sampling technique. The statistical test used is the spearmen rank test. Results: the results of this study are that the majority of the role of leaders is in the good category (92.6%), the majority of patient safety culture is in the good category (90.7%) there is a significant relationship between the role of leaders and the implementation of patient safety culture with a p-value of 0.00 , and r : 0.381, conclusion: Increasing the role of a leader in the form of a decision-making role, interpersonal role, and informational role can improve patient safety culture
We present new observations of MRG-M2129, a quiescent galaxy at z = 2.15 with the Atacama Large Millimeter/submillimeter Array (ALMA). With the combination of the gravitational lensing effect by the ...foreground cluster and the angular resolution provided by ALMA, our data reveal 1.2 mm continuum emission at \(\sim130\) pc angular resolution. Compact dust continuum is detected at 7.9 \(\sigma\) in the target but displaced from its stellar peak position by \(62 \pm 38\) mas, or \(\sim169 \pm 105\) pc in the source plane. We find considerably high dust-to-stellar mass ratio, \(4 \times 10^{-4}\). From non-detection of the C i 3P2 -> 3P1 line, we then derive \(3 \sigma\) upper limits on the molecular gas-to-dust mass ratio \(\delta_\mathrm{GDR} < 60\) and the molecular gas-to-stellar mass ratio fH2 < 2.3%. The derived \(\delta_\mathrm{GDR}\) is \(>2\times\) smaller than the typical value assumed for quiescent galaxies in the literature. Our study supports that there exists a broad range of \(\delta_\mathrm{GDR}\) and urges submillimeter follow-up observations of quenching/recently quenched galaxies at similar redshifts. Based on the derived low \(\delta_\mathrm{GDR}\) and other observed dust properties, we argue that the central black hole is still active and regulates star formation in the system. Our study exhibits a rare case of a gravitationally lensed type 2 QSO harbored by a quiescent galaxy.
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