147 research outputs found

    Remarkably Compact Quiescent Candidates at 3<z<53<z<5 in JWST-CEERS

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    In this letter, we measure the rest-frame optical and near-infrared sizes of ten quiescent candidates at 3<z<53<z<5, first reported by Carnall et al. (2023a). We use James Webb Space Telescope (JWST) Near-Infrared Camera (NIRCam) F277W and F444W imaging obtained through the public CEERS Early Release Science (ERS) program and imcascade, an astronomical fitting code that utilizes Multi-Gaussian Expansion, to carry out our size measurements. When compared to the extrapolation of rest-optical size-mass relations for quiescent galaxies at lower redshift, eight out of ten candidates in our sample (80%) are on average more compact by āˆ¼\sim40%. Seven out of ten candidates (70%) exhibit rest-frame infrared sizes āˆ¼\sim10% smaller than rest-frame optical sizes, indicative of negative color gradients. Two candidates (20%) have rest-frame infrared sizes āˆ¼\sim1.4Ɨ\times larger than rest-frame optical sizes; one of these candidates exhibits signs of ongoing or residual star formation, suggesting this galaxy may not be fully quenched. The remaining candidate is unresolved in both filters, which may indicate an Active Galactic Nuclei (AGN). Strikingly, we observe three of the most massive galaxies in the sample (log(Mā‹†_{\star}/MāŠ™_{\odot}) = 10.74 - 10.95) are extremely compact, with effective radii āˆ¼{\sim}0.7 kpc. Our findings provide no indication that the size evolution relation flattens out, and may indicate that the size evolution of quiescent galaxies is steeper than previously anticipated beyond z>3z>3.Comment: Accepted for publication in ApJL. 11 pages, 4 figures, 1 tabl

    The Vehicle, Spring 1994

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    Table of Contents Thoughts in the IGASue Songerpage 6 The Cries of an Innocent Tea BagWojnarowski Yvonnepage 7 Proud HarpySusan Eisenhourpage 8 Bus Number TwoMindy Glazepage 9 My Home TownScott Langenpage 10 MemoriesMaggie Willpage 11 Vase (Artwork)Gail Valkerpage 12 The Last HuntMark Kannmacherpage 13 Corn DanceJulia A. Canhampage 14 Untitled (Photography)Rachel Corbettpage 14 Paradise (Artwork)Gail Valkerpage 15 Holding Back A ScreamElise Kirarpage 16 poetry isJonathan W. Iwanskipage 17 loveCatherine DeGraafpage 18 The OneTim Rileypage 18 Reading His Words on a Frosty EveningTom McGrathpage 19 UntitledBob Newellpage 19 The Ice StormMindy Glazepage 20 UntitledJonathan W. Iwanskipage 21 Untitled (Photography)Rachel Corbettpage 23 cityscapeChris Pomeroypage 24 Untitled (Photography)Rachel Corbettpage 25 Quarter Pound TemptationBryan Levekpage 26 Photograph (Artwork)Gail Valkerpage 29 Don\u27t Talk to StrangersJon Montgomerypage 30 Untitled (Photography)Rachel Corbettpage 33 Charleston, U.S.A. (Artwork)Gail Valkerpage 34 Fun With Nature (Artwork)Gail Valkerpage 34https://thekeep.eiu.edu/vehicle/1064/thumbnail.jp

    Accumulation of the transcription factor ABA-insensitive (ABI)4 is tightly regulated post-transcriptionally

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    ABA-INSENSITIVE (ABI)4 is a transcription factor implicated in response to ABA in maturing seeds, and seedling responses to ABA, salt, and sugar. Previous studies have shown that ABI4 transcripts are high in seeds and in seedlings exposed to high concentrations of glucose and, to a lesser extent, osmotic agents and ABA, but that transcript levels are very low through most of vegetative growth. This study examined ABI4 protein accumulation indirectly, using transgenic lines expressing fusions to GFP and GUS. The GFP fusions were active, but undetectable visually or immunologically. Comparison of transcript and activity levels for GUS expression showed that inclusion of the ABI4 coding sequence reduced the ratio of activity to transcript āˆ¼40-fold when driven by the CaMV 35S promoter, and nearly 150-fold when controlled by the ABI4 promoter. At least part of this discrepancy is due to proteasomal degradation of ABI4, resulting in a half-life of 5ā€“6 h for the ABI4ā€“GUS fusion. Comparison of the spatial localization of transcripts and fusion proteins indicated that the protein preferentially accumulated in roots such that transcript and protein distribution had little similarity. The components mediating targeting to the proteasome or other mechanisms of spatial restriction have not yet been identified, but several domains of ABI4 appear to contribute to its instability

    Bostonia

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    Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

    Wide-area mapping of small-scale features in agricultural landscapes using airborne remote sensing

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    Natural and semi-natural habitats in agricultural landscapes are likely to come under increasing pressure with the global population set to exceed 9 billion by 2050. These non-cropped habitats are primarily made up of trees, hedgerows and grassy margins and their amount, quality and spatial configuration can have strong implications for the delivery and sustainability of various ecosystem services. In this study high spatial resolution (0.5 m) colour infrared aerial photography (CIR) was used in object based image analysis for the classification of non-cropped habitat in a 10,029 ha area of southeast England. Three classification scenarios were devised using 4 and 9 class scenarios. The machine learning algorithm Random Forest (RF) was used to reduce the number of variables used for each classification scenario by 25.5 % Ā± 2.7%. Proportion of votes from the 4 class hierarchy was made available to the 9 class scenarios and where the highest ranked variables in all cases. This approach allowed for misclassified parent objects to be correctly classified at a lower level. A single object hierarchy with 4 class proportion of votes produced the best result (kappa 0.909). Validation of the optimum training sample size in RF showed no significant difference between mean internal out-of-bag error and external validation. As an example of the utility of this data, we assessed habitat suitability for a declining farmland bird, the yellowhammer (Emberiza citronella), which requires hedgerows associated with grassy margins. We found that āˆ¼22% of hedgerows were within 200 m of margins with an area >183.31 m2. The results from this analysis can form a key information source at the environmental and policy level in landscape optimisation for food production and ecosystem service sustainability

    UNCOVER: Illuminating the Early Universe -- JWST/NIRSpec Confirmation of z>12z > 12 Galaxies

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    Observations of high-redshift galaxies provide a critical direct test to the theories of early galaxy formation, yet to date, only four have been spectroscopically confirmed at z>12z>12. Due to strong gravitational lensing over a wide area, the galaxy cluster field Abell~2744 is ideal for searching for the earliest galaxies. Here we present JWST/NIRSpec observations of two galaxies: a robust detection at zspec=12.393āˆ’0.001+0.004z_{\rm spec} = 12.393^{+0.004}_{-0.001}, and a plausible candidate at zspec=13.079āˆ’0.001+0.013z_{\rm spec} = 13.079^{+0.013}_{-0.001}. The galaxies are discovered in JWST/NIRCam imaging and their distances are inferred with JWST/NIRSpec spectroscopy, all from the JWST Cycle 1 UNCOVER Treasury survey. Detailed stellar population modeling using JWST NIRCam and NIRSpec data corroborates the primeval characteristics of these galaxies: low mass (āˆ¼108Ā MāŠ™\sim 10^8~{\rm M_\odot}), young, rapidly-assembling, metal-poor, and star-forming. Interestingly, both galaxies are spatially resolved, having lensing-corrected rest-UV effective radii on the order of 300-400 pc, which are notably larger than other spectroscopically confirmed zā‰³12z \gtrsim 12 systems. The observed dynamic range of zā‰³12z \gtrsim 12 size spans over an order of magnitude, implying a significant scatter in the size-mass relation at early times. Deep into the epoch of reionization, these discoveries elucidate the emergence of the first galaxies.Comment: submitted to ApJL; 13 pages, 4 figures, 2 table

    UNCOVER: The growth of the first massive black holes from JWST/NIRSpec -- spectroscopic confirmation of an X-ray luminous AGN at z=10.1

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    The James Webb Space Telescope is now detecting early black holes (BHs) as they transition from "seeds" to supermassive BHs. Recently Bogdan et al. (2023) reported the detection of an X-ray luminous supermassive BH, UHZ-1, with a photometric redshift at z>10z > 10. Such an extreme source at this very high redshift provides new insights on seeding and growth models for BHs given the short time available for formation and growth. Harnessing the exquisite sensitivity of JWST/NIRSpec, here we report the spectroscopic confirmation of UHZ-1 at z=10.073Ā±0.002z = 10.073 \pm 0.002. We find that the NIRSpec/Prism spectrum is typical of recently discovered z~10 galaxies, characterized primarily by star-formation features. We see no clear evidence of the powerful X-ray source in the rest-frame UV/optical spectrum, which may suggest heavy obscuration of the central BH, in line with the Compton-thick column density measured in the X-rays. We perform a stellar population fit simultaneously to the new NIRSpec spectroscopy and previously available photometry. The fit yields a stellar mass estimate for the host galaxy that is significantly better constrained than prior photometric estimates (Māˆ—āˆ¼1.4āˆ’0.4+0.3Ɨ108MāŠ™M_*\sim 1.4^{+0.3}_{-0.4} \times 10^8 M_\odot). Given the predicted BH mass (MBHāˆ¼107āˆ’108MāŠ™M_{\rm BH}\sim10^7-10^8 M_\odot), the resulting ratio of MBH/Māˆ—M_{\rm BH}/M_* remains two to three orders of magnitude higher than local values, thus lending support to the heavy seeding channel for the formation of supermassive BHs within the first billion years of cosmic evolution.Comment: 9 pages, 4 figures, submitted to ApJL. Minor text correction

    UNCOVER: A NIRSpec Identification of a Broad-line AGN at z = 8.50

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    Deep observations with the James Webb Space Telescope (JWST) have revealed an emerging population of red pointlike sources that could provide a link between the postulated supermassive black hole seeds and observed quasars. In this work, we present a JWST/NIRSpec spectrum from the JWST Cycle 1 UNCOVER Treasury survey of a massive accreting black hole at z = 8.50 displaying a clear broad-line component as inferred from the HĪ² line with FWHM = 3439 Ā± 413 km sāˆ’1, typical of the broad-line region of an active galactic nucleus (AGN). The AGN nature of this object is further supported by high ionization, as inferred from emission lines, and a point-source morphology. We compute a black hole mass of and a bolometric luminosity of Lbol āˆ¼ 6.6 Ɨ 1045 erg sāˆ’1. These values imply that our object is accreting at āˆ¼40% of the Eddington limit. Detailed modeling of the spectral energy distribution in the optical and near-infrared, together with constraints from ALMA, indicate an upper limit on the stellar mass of , which would lead to an unprecedented ratio of black hole to host mass of at least āˆ¼30%. This is orders of magnitude higher compared to the local QSOs but consistent with recent AGN studies at high redshift with JWST. This finding suggests that a nonnegligible fraction of supermassive black holes either started out from massive seeds and/or grew at a super-Eddington rate at high redshift. Given the predicted number densities of high-z faint AGN, future NIRSpec observations of larger samples will allow us to further investigate galaxyā€“black hole coevolution in the early Universe
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