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1. PEARLS: Near-infrared Photometry in the JWST North Ecliptic Pole Time Domain Field*

   https://doi.org/10.3847/1538-4365/acf57d  

   Willmer, Christopher_N A; Ly, Chun; Kikuta, Satoshi; Kattner, S A; Jansen, Rolf A; Cohen, Seth H; Windhorst, Rogier A; Smail, Ian; Tompkins, Scott; Beacom, John F; et al (November 2023, The Astrophysical Journal Supplement Series)

   Abstract We present near-infrared (NIR) ground-basedY,J,H, andKimaging obtained in the James Webb Space Telescope (JWST) North Ecliptic Pole Time Domain Field (NEP TDF) using the MMT-Magellan Infrared Imager and Spectrometer on the MMT. These new observations cover a field of approximately 230 arcmin²inY,H, andK,and 313 arcmin²inJ. Using Monte Carlo simulations, we estimate a 1σdepth relative to the background sky of (Y, J, H, K) = (23.80, 23.53, 23.13, 23.28) in AB magnitudes for point sources at a 95% completeness level. These observations are part of the ground-based effort to characterize this region of the sky, supplementing space-based data obtained with Chandra, NuSTAR, XMM, AstroSat, Hubble Space Telescope, and JWST. This paper describes the observations and reduction of the NIR imaging and combines these NIR data with archival imaging in the visible, obtained with the Subaru Hyper-Suprime-Cam, to produce a merged catalog of 57,501 sources. The new observations reported here, plus the corresponding multiwavelength catalog, will provide a baseline for time-domain studies of bright sources in the NEP TDF. 

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2. Subaru/Hyper Suprime-Cam z-Broadband Excess Selection of Extreme Emission Line Galaxies at z < 1

   https://doi.org/10.3847/1538-4357/ac5117  

   Rosenwasser, Benjamin E.; Taylor, Anthony J.; Barger, Amy J.; Cowie, Lennox L.; Hu, Esther M.; Jones, Logan H.; Songaila, Antoinette (March 2022, The Astrophysical Journal)

   Abstract We present a search for extreme emission line galaxies (EELGs) at z < 1 in the COSMOS and North Ecliptic Pole (NEP) fields with imaging from Subaru/Hyper Suprime-Cam (HSC) and a combination of new and existing spectroscopy. We select EELGs on the basis of substantial excess flux in the z broad band, which is sensitive to H α at 0.3 ≲ z ≲ 0.42 and [O iii ] λ 5007 at 0.7 ≲ z ≲ 0.86. We identify 10,470 galaxies with z excesses in the COSMOS data set and 91,385 in the NEP field. We cross-reference the COSMOS EELG sample with the zCOSMOS and DEIMOS 10k spectral catalogs, finding 1395 spectroscopic matches. We made an additional 71 (46 unique) spectroscopic measurements with Y < 23 using the HYDRA multiobject spectrograph on the WIYN 3.5 m telescope, and 204 spectroscopic measurements from the DEIMOS spectrograph on the Keck II telescope, providing a total of 1441/10,470 spectroscopic redshifts for the EELG sample in COSMOS (∼14%). We confirm that 1418 (∼98%) are H α or [O iii ] λ 5007 emitters in the above stated redshift ranges. We also identify 240 redshifted H α and [O iii ] λ 5007 emitters in the NEP using spectra taken with WIYN/HYDRA and Keck/DEIMOS. Using broadband-selection techniques in the g − r − i color space, we distinguish between H α and [O iii ] λ 5007 emitters with 98.6% accuracy. We test our EELG selection by constructing H α and [O iii ] λ 5007 luminosity functions and comparing to recent literature results. We conclude that broadband magnitudes from HSC, the Vera C. Rubin Observatory, and other deep optical multiband surveys can be used to select EELGs in a straightforward manner. 

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3. Large-scale Overdensity of Lyman Break Galaxies around the z = 6.3 Ultraluminous Quasar J0100 + 2802

   https://doi.org/10.3847/1538-4357/ad488a  

   Pudoka, Maria; Wang, Feige; Fan, Xiaohui; Yang, Jinyi; Champagne, Jaclyn; Jones, Victoria; Bian, Fuyan; Cai, Zheng; Jiang, Linhua; Liu, Dezi; et al (June 2024, The Astrophysical Journal)

   Abstract We study the environment of thez= 6.33 ultraluminous quasar SDSS J010013.02+280225.8 (J0100) to understand its association with large-scale structure. Theoretical models propose high-redshift quasars as markers of galaxy overdensities residing in the most massive dark matter halos (DMHs) in the early Universe. J0100 is an ultraluminous quasar with the most massive black hole known atz≳ 6, suggesting a high likelihood of residing in a massive DMH. We present wide-field (∼522 arcmin²) imaging in ther,i, andzbands from the Large Binocular Cameras on the Large Binocular Telescope, withY-andJ-band imaging from the Wide-field Infrared Camera on the Canada–France–Hawaii Telescope, centered on J0100. Applying color selections, we identify 23 objects asi-dropout Lyman break galaxy (LBG) candidates in the J0100 field. We use the deep photometric catalog in the 1.27 deg²COSMOS field to calculate the density of LBGs in a blank field, and to estimate the selection completeness and purity. The observed surface density of LBG candidates in the J0100 field corresponds to a galaxy overdensity ofδ= 4 (at 8.4σ). This large-scale overdensity suggests that the ∼22 arcmin²overdensity found by Kashino et al. using JWST data extends out to much larger scales. We calculate the angular autocorrelation function of the candidates and find a positive correlation on ≲10′ scales as well as evidence of asymmetries in their spatial distribution, further suggesting the direct detection of large-scale structure in the field of the ultraluminous quasar J0100. 

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4. A Southern Photometric Quasar Catalog from the Dark Energy Survey Data Release 2

   https://doi.org/10.3847/1538-4365/ac9ea8  

   Yang, Qian; Shen, Yue (December 2022, The Astrophysical Journal Supplement Series)

   Abstract We present a catalog of 1.4 million photometrically selected quasar candidates in the southern hemisphere over the ∼5000 deg²Dark Energy Survey (DES) wide survey area. We combine optical photometry from the DES second data release (DR2) with available near-infrared (NIR) and the all-sky unWISE mid-infrared photometry in the selection. We build models of quasars, galaxies, and stars with multivariate skew-tdistributions in the multidimensional space of relative fluxes as functions of redshift (or color for stars) and magnitude. Our selection algorithm assigns probabilities for quasars, galaxies, and stars and simultaneously calculates photometric redshifts (photo-z) for quasar and galaxy candidates. Benchmarking on spectroscopically confirmed objects, we successfully classify (with photometry) 94.7% of quasars, 99.3% of galaxies, and 96.3% of stars when all IR bands (NIRYJHKand WISE W1W2) are available. The classification and photo-zregression success rates decrease when fewer bands are available. Our quasar (galaxy) photo-zquality, defined as the fraction of objects with the difference between the photo-z z_pand the spectroscopic redshiftz_s, ∣Δz∣ ≡ ∣z_s−z_p∣/(1 +z_s) ≤ 0.1, is 92.2% (98.1%) when all IR bands are available, decreasing to 72.2% (90.0%) using optical DES data only. Our photometric quasar catalog achieves an estimated completeness of 89% and purity of 79% atr< 21.5 (0.68 million quasar candidates), with reduced completeness and purity at 21.5 <r≲ 24. Among the 1.4 million quasar candidates, 87,857 have existing spectra, and 84,978 (96.7%) of them are spectroscopically confirmed quasars. Finally, we provide quasar, galaxy, and star probabilities for all (0.69 billion) photometric sources in the DES DR2 coadded photometric catalog. 

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5. Response of lake metabolism to catchment inputs inferred using high‐frequency lake and stream data from across the northern hemisphere

   https://doi.org/10.1002/lno.12449  

   Corman, Jessica R.; Zwart, Jacob A.; Klug, Jennifer; Bruesewitz, Denise A.; de Eyto, Elvira; Klaus, Marcus; Knoll, Lesley B.; Rusak, James A.; Vanni, Michael J.; Alfonso, María Belén; et al (December 2023, Limnology and Oceanography)

   Abstract In lakes, the rates of gross primary production (GPP), ecosystem respiration (R), and net ecosystem production (NEP) are often controlled by resource availability. Herein, we explore how catchment vs. within lake predictors of metabolism compare using data from 16 lakes spanning 39°N to 64°N, a range of inflowing streams, and trophic status. For each lake, we combined stream loads of dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorus (TP) with lake DOC, TN, and TP concentrations and high frequencyin situmonitoring of dissolved oxygen. We found that stream load stoichiometry indicated lake stoichiometry for C : N and C : P (r² = 0.74 andr² = 0.84, respectively), but not for N : P (r² = 0.04). As we found a strong positive correlation between TN and TP, we only used TP in our statistical models. For the catchment model, GPP and R were best predicted by DOC load, TP load, and load N : P (R² = 0.85 andR² = 0.82, respectively). For the lake model, GPP and R were best predicted by TP concentrations (R² = 0.86 andR² = 0.67, respectively). The inclusion of N : P in the catchment model, but not the lake model, suggests that both N and P regulate metabolism and that organisms may be responding more strongly to catchment inputs than lake resources. Our models predicted NEP poorly, though it is unclear why. Overall, our work stresses the importance of characterizing lake catchment loads to predict metabolic rates, a result that may be particularly important in catchments experiencing changing hydrologic regimes related to global environmental change. 

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