33 research outputs found
EPOCHS. IV. SED Modeling Assumptions and Their Impact on the Stellar Mass Function at 6.5 ≤ z ≤ 13.5 Using PEARLS and Public JWST Observations
We utilize deep JWST Near Infrared Camera (NIRCam) observations for the first direct constraints on the Galaxy Stellar Mass Function (GSMF) at z > 10. Our EPOCHS v1 sample includes 1120 galaxy candidates at 6.5 < z < 13.5 taken from a consistent reduction and analysis of publicly available deep JWST NIRCam data covering the Prime Extragalactic Areas for Reionization Science, CEERS, GLASS, JADES GOOD-S, NGDEEP, and SMACS0723 surveys, totaling 187 arcmin2. We investigate the impact of spectral energy distribution fitting methods, assumed star formation histories (SFHs), dust laws, and priors on galaxy masses and the resultant GSMF. While our fiducial GSMF agrees with the literature at z < 13.5, we find that the assumed SFH model has a large impact on the GSMF and stellar mass density (SMD), finding a 0.75 dex increase in the SMD at z = 10.5 between a flexible nonparametric and standard parametric SFH. Overall, we find a flatter SMD evolution at z ≥ 9 than some studies predict, suggesting a rapid buildup of stellar mass in the early Universe. We find no incompatibility between our results and those of standard cosmological models, as suggested previously, although the most massive galaxies may require a high star formation efficiency. We find that the “little red dot” galaxies dominate the z = 7 GSMF at high masses, necessitating a better understanding of the relative contributions of active galactic nucleus and stellar emission. We show that assuming a theoretically motivated top-heavy initial mass function (IMF) reduces stellar mass by 0.5 dex without affecting fit quality, but our results remain consistent with existing cosmological models with a standard IMF
Trends in Employment for Individuals with Autism Spectrum Disorder: a Review of the Research Literature
Long-term exposure to telmisartan as monotherapy or combination therapy : Efficacy and safety
This multicentre, open-label extension study to four controlled trials involved 888 patients with mild-to-moderate primary hypertension. Patients received telmisartan 40-80 mg once daily with add-on hydrochlorothiazide (HCTZ, 12.5-25 mg) if necessary and/or other antihypertensives to achieve diastolic blood pressure (DBP) control (</p
Valsartan, a new angiotensin II antagonist for the treatment of essential hypertension: efficacy and safety compared with placebo and enalapril
OBJECTIVE: To compare the antihypertensive efficacy and systemic tolerability of valsartan, a new angiotensin II receptor antagonist, with placebo and with an angiotensin converting enzyme (ACE) inhibitor, enalapril.
DESIGN: A total of 348 adult outpatients with mild-to-moderate uncomplicated essential hypertension participated in this double-blind, parallel, study. Patients were allocated randomly in a ratio of 2:2:1 to receive 80 mg valsartan once a day, 20 mg enalapril once a day, or placebo for 8 weeks in general practice. Patients were assessed at 4 and 8 weeks of therapy.
MAIN OUTCOME MEASURES: The primary efficacy variable was the change from baseline in mean sitting diastolic blood pressure (SDBP) after 8 weeks of therapy. Secondary variables included the change in sitting systolic blood pressure (SSBP) and response rates at 8 weeks.
RESULTS: Valsartan and enalapril produced statistically significant reductions in diastolic and systolic blood pressures compared with placebo. Similar falls were found in both of the active treatment groups with mean changes in SDBP at 8 weeks of -9.5 mmHg for valsartan and -9.4 mmHg for enalapril (-4.5 mmHg for placebo). No significant differences between valsartan and enalapril were found for reductions in SDBP or SSBP. Response rates at 8 weeks were significantly greater for valsartan (54%) and enalapril (58%) than for placebo (20%), with no significant difference between the two active treatments. Both valsartan and enalapril demonstrated a consistent antihypertensive effect over time, with 90% of patients with a response at 4 weeks responding at 8 weeks. Both of the treatments were tolerated well. Although the incidence of coughing was generally low in the study, more cases were reported with enalapril (three) than with valsartan (one) or placebo (none).
CONCLUSIONS: The data show 80 mg valsartan once a day to be as effective as 20 mg enalapril once a day in the treatment of mild-to-moderate hypertension. Valsartan is tolerated well and does not appear to be associated with any increase in the incidence of coughin
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Expectations of the Size Evolution of Massive Galaxies at 3 ≤ z ≤ 6 from the TNG50 Simulation: The CEERS/JWST View
Abstract
We present a catalog of about 25,000 images of massive (M
⋆ ≥ 109
M
⊙) galaxies at redshifts 3 ≤ z ≤ 6 from the TNG50 cosmological simulation, tailored for observations at multiple wavelengths carried out with JWST. The synthetic images were created with the SKIRT radiative transfer code, including the effects of dust attenuation and scattering. The noiseless images were processed with the mirage simulator to mimic the Near Infrared Camera (NIRCam) observational strategy (e.g., noise, dithering pattern, etc.) of the Cosmic Evolution Early Release Science (CEERS) survey. In this paper, we analyse the predictions of the TNG50 simulation for the size evolution of galaxies at 3 ≤ z ≤ 6 and the expectations for CEERS to probe that evolution. In particular, we investigate how sizes depend on the wavelength, redshift, mass, and angular resolution of the images. We find that the effective radius accurately describes the three-dimensional half-mass–radius of the TNG50 galaxies. Sizes observed at 2 μm are consistent with those measured at 3.56 μm at all redshifts and masses. At all masses, the population of higher-z galaxies is more compact than their lower-z counterparts. However, the intrinsic sizes are smaller than the mock observed sizes for the most massive galaxies, especially at z ≲ 4. This discrepancy between the mass and light distributions may point to a transition in the galaxy morphology at z = 4–5, where massive compact systems start to develop more extended stellar structures.
22
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Data publicly released at https://www.tng-project.org/costantin22.
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[Letter] Spectroscopic confirmation of a dust-obscured, possibly metal-rich dwarf galaxy at z ∼ 5
We present the first spectroscopic confirmation of a dust-obscured dwarf galaxy, CEERS-14821. The analysis was performed by combining JWST NIRCam broadband photometry and NIRSpec/PRISM spectroscopic data. From the detection of multiple rest-frame optical lines, we derive that CEERS-14821 is located at z = 4.883 ± 0.003. Moreover, from a secure detection of the Hα and Hβ, we derive that the galaxy has a dust extinction ranging from AV = 2.20.6+0.5 to AV = 3.40.9+0.7, depending on the assumed reddening law. This value is extremely large given that we estimated a low stellar mass, that is, log10(M/M⊙) = 8.170.04+0.05 or log10(M/M⊙) = 8.650.05+0.06, based on two different dust extinction laws. Moreover, the combination of different metallicity tracers and the spectro-photometric fit suggests that the galaxy may also be metal-rich, with 12 + log10(O/H)> 8.3, but a low metallicity value cannot be totally ruled out. The high metallicity value would be above the expectation based on the mass-metallicity relation. Both metallicity estimations are above the expectations based on the fundamental mass-metallicity relation since CEERS-14821 is going through a burst of star formation. The constraints on a possible active galactic nucleus presence are limited and loose, but they point towards a possible non-dominant contribution (fAGN </p
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Identifying Galaxy Mergers in Simulated CEERS NIRCam Images Using Random Forests
Abstract
Identifying merging galaxies is an important—but difficult—step in galaxy evolution studies. We present random forest (RF) classifications of galaxy mergers from simulated JWST images based on various standard morphological parameters. We describe (a) constructing the simulated images from IllustrisTNG and the Santa Cruz SAM and modifying them to mimic future CEERS observations and nearly noiseless observations, (b) measuring morphological parameters from these images, and (c) constructing and training the RFs using the merger history information for the simulated galaxies available from IllustrisTNG. The RFs correctly classify ∼60% of non-merging and merging galaxies across 0.5 < z < 4.0. Rest-frame asymmetry parameters appear more important for lower-redshift merger classifications, while rest-frame bulge and clump parameters appear more important for higher-redshift classifications. Adjusting the classification probability threshold does not improve the performance of the forests. Finally, the shape and slope of the resulting merger fraction and merger rate derived from the RF classifications match with theoretical Illustris predictions but are underestimated by a factor of ∼0.5.</jats:p
Deep Extragalactic VIsible Legacy Survey (DEVILS): consistent multiwavelength photometry for the DEVILS regions (COSMOS, XMMLSS, and ECDFS)
The Deep Extragalactic VIsible Legacy Survey (DEVILS) is an ongoing high-completeness, deep spectroscopic survey of ∼60 000 galaxies to Y < 21.2 mag, over ∼6 deg2 in three well-studied deep extragalactic fields: D10 (COSMOS), D02 (XMMLSS), and D03 (ECDFS). Numerous DEVILS projects all require consistent, uniformly derived and state-of-the-art photometric data with which to measure galaxy properties. Existing photometric catalogues in these regions either use varied photometric measurement techniques for different facilities/wavelengths leading to inconsistencies, older imaging data and/or rely on source detection and photometry techniques with known problems. Here, we use the PROFOUND image analysis package and state-of-the-art imaging data sets (including Subaru-HSC, VST-VOICE, VISTA-VIDEO, and UltraVISTA-DR4) to derive matched-source photometry in 22 bands from the FUV to 500 μm. This photometry is found to be consistent, or better, in colour analysis to previous approaches using fixed-size apertures (which are specifically tuned to derive colours), but produces superior total source photometry, essential for the derivation of stellar masses, star formation rates, star formation histories, etc. Our photometric catalogue is described in detail and, after internal DEVILS team projects, will be publicly released for use by the broader scientific community
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Identifying Galaxy Mergers in Simulated CEERS NIRCam Images Using Random Forests
Abstract
Identifying merging galaxies is an important—but difficult—step in galaxy evolution studies. We present random forest (RF) classifications of galaxy mergers from simulated JWST images based on various standard morphological parameters. We describe (a) constructing the simulated images from IllustrisTNG and the Santa Cruz SAM and modifying them to mimic future CEERS observations and nearly noiseless observations, (b) measuring morphological parameters from these images, and (c) constructing and training the RFs using the merger history information for the simulated galaxies available from IllustrisTNG. The RFs correctly classify ∼60% of non-merging and merging galaxies across 0.5 < z < 4.0. Rest-frame asymmetry parameters appear more important for lower-redshift merger classifications, while rest-frame bulge and clump parameters appear more important for higher-redshift classifications. Adjusting the classification probability threshold does not improve the performance of the forests. Finally, the shape and slope of the resulting merger fraction and merger rate derived from the RF classifications match with theoretical Illustris predictions but are underestimated by a factor of ∼0.5.</jats:p
