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We present a spectroscopic survey of Ly α emitters in the Extended Groth Strip (EGS) field, targeting the regime near the Epoch of Reionization. Using Keck/DEep Imaging Multi-Object Spectrograph, we observed 947 high- z candidates with photometric redshifts from 3 < z phot < 7 and down to an H -band (Hubble Space Telescope /Wide Field Camera 3 F160W) magnitude limit of <27.5. Observations were taken over the course of eight nights, with integration times ranging from 4 to 7.8 h. Our survey secured 137 unique redshifts, 126 of which are Ly α emitters at 2.8 < z < 6.3 with a mean redshift of |$\overline{z} = 4.3$|⁠. We provide a comprehensive redshift catalogue for our targets, as well as the reduced one- and two-dimensional spectra for each object. These observations will provide an important auxiliary data set for the JWST Directors Discretionary Early Release Science programme the Cosmic Evolution Early Release Science Survey, which recently completed near- and mid-infrared imaging and spectroscopy of galaxies in the EGS field. [ABSTRACT FROM AUTHOR]

The PASSAGES (Planck All-Sky Survey to Analyze Gravitationally-lensed Extreme Starbursts) collaboration has recently defined a sample of 30 gravitationally lensed dusty star-forming galaxies (DSFGs). These rare, submillimeter-selected objects enable high-resolution views of the most extreme sites of star formation in galaxies at cosmic noon. Here, we present the first major compilation of strong lensing analyses using lenstool for PASSAGES, including 15 objects spanning z = 1.1–3.3, using complementary information from 0.″6-resolution 1.1 mm Atacama Large Millimeter/submillimeter Array and 0.″4 5 cm Jansky Very Large Array continuum imaging, in tandem with 1.6 μ m Hubble and optical imaging with Gemini-S. Magnifications range from μ = 2 to 28 (median μ = 7), yielding intrinsic infrared luminosities of L IR = 0.2–5.9 × 1013 L ⊙ (median 1.4 × 1013 L ⊙) and inferred star formation rates of 170–6300 M ⊙ yr−1 (median 1500 M ⊙ yr−1). These results suggest that the PASSAGES objects comprise some of the most extreme known starbursts, rivaling the luminosities of even the brightest unlensed objects, further amplified by lensing. The intrinsic sizes of far-infrared continuum regions are large (R e = 1.7–4.3 kpc; median 3.0 kpc) but consistent with L IR– R e scaling relations for z > 1 DSFGs, suggesting a widespread spatial distribution of star formation. With modestly high angular resolution, we explore if these objects might be maximal starbursts. Instead of approaching Eddington-limited surface densities, above which radiation pressure will disrupt further star formation, they are safely sub-Eddington—at least on global, galaxy-integrated scales. [ABSTRACT FROM AUTHOR]

A growing number of far-infrared (FIR) bright sources completely invisible in deep extragalactic optical surveys hint at an elusive population of z > 4 dusty, star-forming galaxies. Cycle 1 JWST surveys are now detecting their rest-frame optical light, which provides key insight into their stellar properties and statistical constraints on the population as a whole. This work presents the JWST Near Infrared Camera (NIRCam) counterpart from the COSMOS-Web survey to an FIR SCUBA-2 and Atacama Large Millimeter/submillimeter Array (ALMA) source, AzTECC71, which was previously undetected at wavelengths shorter than 850 μ m. AzTECC71, among the reddest galaxies in COSMOS-Web with F277W − F444W ∼ 0.9, is undetected in NIRCam/F150W and F115W and fainter in F444W than other submillimeter galaxies identified in COSMOS-Web by 2–4 magnitudes. This is consistent with the system having both a lower stellar mass and higher redshift than the median dusty, star-forming galaxy. With deep ground- and space-based upper limits combined with detections in F277W, F444W, and the FIR including ALMA Band 6, we find a high probability (99%) that AzTECC71 is at z > 4 with z phot = 5.7 − 0.7 + 0.8 . This galaxy is massive ( log M * / M ⊙ ∼ 10.7) and infrared-luminous ( log L IR / L ⊙ ∼ 12.7), comparable to other optically undetected but FIR-bright dusty, star-forming galaxies at z > 4. This population of luminous, infrared galaxies at z > 4 is largely unconstrained but comprises an important bridge between the most extreme dust-obscured galaxies and more typical high-redshift star-forming galaxies. If further FIR-selected galaxies that drop out of the F150W filter in COSMOS-Web have redshifts z > 4 like AzTECC71, then the volume density of such sources may be ∼3–10 × greater than previously estimated. [ABSTRACT FROM AUTHOR]

An inherent aspect of learner-controlled instructional environments is the ability of learners to affect the degree of difficulty faced during training. However, research has yet to examine how learner-controlled practice difficulty affects learning. Based on the notion of "desirable difficulties" (Bjork, 1994), this study examined the cognitive and motivational antecedents and outcomes of learner-controlled practice difficulty in relation to learning a complex task. Using a complex videogame involving both strong cognitive and psychomotor demands, 112 young adult males were given control over their practice difficulty, which was reflected in the complexity of the training task. Results show that general mental ability, prior experience, pre-training self-efficacy, and error encouragement were positively related to learner-controlled practice difficulty. In turn, practice difficulty was directly related to task knowledge and post-training performance, and it was related to adaptive performance through the mediating influences of task knowledge and post-training performance. In general, this study supports the notion that training difficulty operationalized in terms of task complexity is positively related to both knowledge and performance outcomes. Results are discussed with respect to the need for more research examining how task complexity and other forms of difficulty could be leveraged to advance learner-controlled instructional practices. (Contains 2 tables and 3 figures.)

Due to their extremely dust-obscured nature, much uncertainty still exists surrounding the stellar mass growth and content in dusty, star-forming galaxies (DSFGs) at z > 1. In this work, we present a numerical model built using empirical data on DSFGs to estimate their stellar mass contributions across the first ∼10 Gyr of cosmic time. We generate a dust-obscured stellar mass function that extends beyond the mass limit of star-forming stellar mass functions in the literature, and predict that massive DSFGs constitute as much as 50%–100% of all star-forming galaxies with M ≥1011 M ⊙ at z > 1. We predict the number density of massive DSFGs and find general agreement with observations, although more data is needed to narrow wide observational uncertainties. We forward-model mock massive DSFGs to their quiescent descendants and find remarkable agreement with observations from the literature demonstrating that, to first order, massive DSFGs are a sufficient ancestral population to describe the prevalence of massive quiescent galaxies at z > 1. We predict that massive DSFGs and their descendants contribute as much as 25%–60% to the cosmic stellar mass density during the peak of cosmic star formation, and predict an intense epoch of population growth during the ∼1 Gyr from z = 6 to 3 during which the majority of the most massive galaxies at high- z grow and then quench. Future studies seeking to understand massive galaxy growth and evolution in the early universe should strategize synergies with data from the latest observatories (e.g., JWST and the Atacama Large Millimeter/submillimeter Array) to better include the heavily dust-obscured galaxy population. [ABSTRACT FROM AUTHOR]

The most luminous quasars at z > 6 are suspected to be both highly clustered and to reside in the most massive dark matter halos in the early universe, making them prime targets to search for galaxy overdensities and/or protoclusters. We search for Lyman-break dropout-selected galaxies using HST WFC3/ACS broadband imaging in the fields of three 6 < z < 7 quasars, as well as for their simultaneously observed coordinated parallel fields, and constrain their photometric redshifts using EAZY. One field, J0305-3150, shows a volume density 10× higher than the blank-field UV luminosity function (UVLF) at M UV < −20, with tentative evidence of a 3 σ overdensity in its parallel field located 15 cMpc away. Another field, J2054–0005, shows an angular overdensity within 500 ckpc from the quasar, but this is still consistent with UVLF predictions within 3 σ, while the last field, J2348–3054, shows no enhancement. We discuss methods for reducing uncertainty in overdensity measurements when using photometric selection and show that we can robustly select Lyman-break galaxies (LBGs) consistent with being physically associated with the quasar, corroborated by existing JWST/NIRCam WFSS data in the J0305 field. Even accounting for incompleteness, the overdensities in J0305 and J2054 are higher for brighter galaxies at short angular separations, suggesting preferential enhancement of more massive galaxies in the quasar's immediate vicinity. Finally, we compare the population of LBGs with previously identified [C ii ] and millimeter-continuum companions. The LBG overdensities are not accompanied by an enhanced number of dusty galaxies, suggesting that the overdense quasar fields are not in the bursty star-forming phase sometimes seen in high-redshift protoclusters. [ABSTRACT FROM AUTHOR]

A complete census of dusty star-forming galaxies (DSFGs) at early epochs is necessary to constrain the obscured contribution to the cosmic star formation rate density (CSFRD); however, DSFGs beyond z ∼ 4 are both rare and hard to identify from photometric data alone due to degeneracies in submillimeter photometry with redshift. Here, we present a pilot study obtaining follow-up Atacama Large Millimeter Array (ALMA) 2 mm observations of a complete sample of 39 850 ÎĽ m-bright dusty galaxies in the SSA22 field. Empirical modeling suggests 2 mm imaging of existing samples of DSFGs selected at 850 ÎĽ mâ€"1 mm can quickly and easily isolate the “needle in a haystack” DSFGs that sit at z > 4 or beyond. Combining archival submillimeter imaging with our measured ALMA 2 mm photometry (1 σ ∼ 0.08 mJy beamâˆ'1 rms), we characterize the galaxies’ IR spectral energy distributions (SEDs) and use them to constrain redshifts. With available redshift constraints fit via the combination of six submillimeter bands, we identify 6/39 high- z candidates each with >50% likelihood to sit at z > 4, and find a positive correlation between redshift and 2 mm flux density. Specifically, our models suggest the addition of 2 mm to a moderately constrained IR SED will improve the accuracy of a millimeter-derived redshift from Î" z /(1 + z) = 0.3 to Î" z /(1 + z) = 0.2. Our IR SED characterizations provide evidence for relatively high-emissivity spectral indices (〈 β 〉 = 2.4 ± 0.3) in the sample. We measure that especially bright (S 850 ÎĽ m > 5.55 mJy) DSFGs contribute ∼10% to the cosmic-averaged CSFRD from 2 < z < 5, confirming findings from previous work with similar samples. [ABSTRACT FROM AUTHOR]

Many inspiraling and merging stellar remnants emit both gravitational and electromagnetic radiation as they orbit or collide. These gravitational wave events together with their associated electromagnetic counterparts provide insight about the nature of the merger, allowing us to further constrain properties of the binary. With the future launch of the Laser Interferometer Space Antenna (LISA), follow-up observations and models are needed of ultracompact binary (UCB) systems. Current and upcoming long baseline time domain surveys will observe many of these UCBs. We present a new fast periodic object search tool capable of searching for generic periodic signals based on the conditional entropy algorithm. This new implementation allows for a grid search over both the period (P) and the time derivative of the period (⁠|$\dot{P}$|⁠). To demonstrate the usage of this tool, we use a small, hand-picked subset of a UCB population generated from the population synthesis code cosmic , as well as a custom catalogue for varying periods at fixed intrinsic parameters. We simulate light curves as likely to be observed by future time domain surveys by using an existing eclipsing binary light-curve model accounting for the change in orbital period due to gravitational radiation. We find that a search with |$\dot{P}$| values is necessary for detecting binaries at orbital periods less than ∼10 min. We also show it is useful in finding and characterizing binaries with longer periods, but at a higher computational cost. Our code is called gce (GPU-accelerated Conditional Entropy). It is available on Github (https://github.com/mikekatz04/gce). [ABSTRACT FROM AUTHOR]

The increased reliance on interorganizational collaborations (ICs) has created new challenges for leaders. They must attempt to apply leadership theories and behaviors developed primarily for leading within one organization or group to leading collaborations of multiple organizations and stakeholders. To provide insight into this issue, this study examines leadership behavior in an IC developing a strategic plan to promote changes to address public health and safety concerns related to substance abuse. Combining observations and interviews, we followed a statewide interagency taskforce in a southwestern state of the United States from its inception through completion of its strategic plan within a 10-month deadline. Findings show different leadership behaviors were integrated and evolved over time to strike a balance between decision-making effectiveness and efficiency. In particular, the findings support recent research on examining leadership behavior holistically to develop a 'fuller full-range' leadership perspective (Antonakis and House, 2014), especially in terms of how collectivistic and instrumental leadership should complement transformational leadership, and by demonstrating that the combinations of leadership change over time and occur at multiple levels. These findings provide guidance for future practice and research on ICs promoting change. [ABSTRACT FROM AUTHOR]