Publications
1044 results found
Prat J, Zacharegkas G, Park Y, et al., 2023, Non-local contribution from small scales in galaxy-galaxy lensing: comparison of mitigation schemes, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 522, Pages: 412-425, ISSN: 0035-8711
Abbott TMC, Aguena M, Alarcon A, et al., 2023, Dark Energy Survey Year 3 results: Constraints on extensions to ΛCDM with weak lensing and galaxy clustering, PHYSICAL REVIEW D, Vol: 107, ISSN: 2470-0010
- Author Web Link
- Cite
- Citations: 6
Cooper AP, Koposov SE, Allende Prieto C, et al., 2023, Overview of the DESI Milky Way Survey, ASTROPHYSICAL JOURNAL, Vol: 947, ISSN: 0004-637X
- Author Web Link
- Cite
- Citations: 10
Guy J, Bailey S, Kremin A, et al., 2023, The Spectroscopic Data Processing Pipeline for the Dark Energy Spectroscopic Instrument, ASTRONOMICAL JOURNAL, Vol: 165, ISSN: 0004-6256
- Author Web Link
- Cite
- Citations: 11
Setton DJ, Dey B, Khullar G, et al., 2023, DESI Survey Validation Spectra Reveal an Increasing Fraction of Recently Quenched Galaxies at z ∼1, Astrophysical Journal Letters, Vol: 947, ISSN: 2041-8205
We utilize 17,000 bright luminous red galaxies (LRGs) from the novel Dark Energy Spectroscopic Instrument Survey Validation spectroscopic sample, leveraging its deep (2.5 hr galaxy-1 exposure time) spectra to characterize the contribution of recently quenched galaxies to the massive galaxy population at 0.4 < z < 1.3. We use Prospector to infer nonparametric star formation histories and identify a significant population of recently quenched galaxies that have joined the quiescent population within the past 1 Gyr. The highest-redshift subset (277 at z > 1) of our sample of recently quenched galaxies represents the largest spectroscopic sample of post-starburst galaxies at that epoch. At 0.4 < z < 0.8, we measure the number density of quiescent LRGs, finding that recently quenched galaxies constitute a growing fraction of the massive galaxy population with increasing look-back time. Finally, we quantify the importance of this population among massive ( log(M⋆/M⊙) > 11.2) LRGs by measuring the fraction of stellar mass each galaxy formed in the gigayear before observation, f 1 Gyr. Although galaxies with f 1 Gyr > 0.1 are rare at z ∼0.4 ( 20.5% of the population), by z ∼0.8, they constitute 3% of massive galaxies. Relaxing this threshold, we find that galaxies with f 1 Gyr > 5% constitute 10% of the massive galaxy population at z ∼0.8. We also identify a small but significant sample of galaxies at z = 1.1-1.3 that formed with f 1 Gyr > 50%, implying that they may be analogs to high-redshift quiescent galaxies that formed on similar timescales. Future analysis of this unprecedented sample promises to illuminate the physical mechanisms that drive the quenching of massive galaxies after cosmic noon.
Hahn CH, Kwon KJ, Tojeiro R, et al., 2023, The DESI PRObabilistic Value-added Bright Galaxy Survey (PROVABGS) Mock Challenge, Astrophysical Journal, Vol: 945, ISSN: 0004-637X
The PRObabilistic Value-added Bright Galaxy Survey (PROVABGS) catalog will provide measurements of galaxy properties, such as stellar mass (M *), star formation rate (SFR), stellar metallicity (Z), and stellar age (t age), for >10 million galaxies of the Dark Energy Spectroscopic Instrument (DESI) Bright Galaxy Survey. Full posterior distributions of the galaxy properties will be inferred using state-of-the-art Bayesian spectral energy distribution (SED) modeling of DESI spectroscopy and Legacy Surveys photometry. In this work, we present the SED model, the neural emulator for the model, and the Bayesian inference framework of PROVABGS. Furthermore, we apply the PROVABGS SED modeling on realistic synthetic DESI spectra and photometry, constructed using the L-Galaxies semi-analytic model. We compare the inferred galaxy properties to the true values of the simulation using a hierarchical Bayesian framework to quantify accuracy and precision. Overall, we accurately infer the true M *, SFR, Z, and t age of the simulated galaxies. However, the priors on galaxy properties induced by the SED model have a significant impact on the posteriors, which we characterize in detail. This work also demonstrates that a joint analysis of spectra and photometry significantly improves the constraints on galaxy properties over photometry alone and is necessary to mitigate the impact of the priors. With the methodology presented and validated in this work, PROVABGS will maximize information extracted from DESI observations and extend current galaxy studies to new regimes and unlock cutting-edge probabilistic analyses. https://github.com/changhoonhahn/provabgs/
Alexander DM, Davis TM, Chaussidon E, et al., 2023, The DESI Survey Validation: Results from Visual Inspection of the Quasar Survey Spectra, Astronomical Journal, Vol: 165, ISSN: 0004-6256
A key component of the Dark Energy Spectroscopic Instrument (DESI) survey validation (SV) is a detailed visual inspection (VI) of the optical spectroscopic data to quantify key survey metrics. In this paper we present results from VI of the quasar survey using deep coadded SV spectra. We show that the majority (≈70%) of the main-survey targets are spectroscopically confirmed as quasars, with ≈16% galaxies, ≈6% stars, and ≈8% low-quality spectra lacking reliable features. A nonnegligible fraction of the quasars are misidentified by the standard spectroscopic pipeline, but we show that the majority can be recovered using post-pipeline “afterburner” quasar-identification approaches. We combine these “afterburners” with our standard pipeline to create a modified pipeline to increase the overall quasar yield. At the depth of the main DESI survey, both pipelines achieve a good-redshift purity (reliable redshifts measured within 3000 km s−1) of ≈99%; however, the modified pipeline recovers ≈94% of the visually inspected quasars, as compared to ≈86% from the standard pipeline. We demonstrate that both pipelines achieve a median redshift precision and accuracy of ≈100 km s−1 and ≈70 km s−1, respectively. We constructed composite spectra to investigate why some quasars are missed by the standard pipeline and find that they are more host-galaxy dominated (i.e., distant analogs of “Seyfert galaxies”) and/or more dust reddened than the standard-pipeline quasars. We also show example spectra to demonstrate the overall diversity of the DESI quasar sample and provide strong-lensing candidates where two targets contribute to a single spectrum.
Madsen LS, Parbo P, Ismail R, et al., 2023, Capillary dysfunction correlates with cortical amyloid load in early Alzheimer's disease, NEUROBIOLOGY OF AGING, Vol: 123, Pages: 1-9, ISSN: 0197-4580
- Author Web Link
- Cite
- Citations: 2
Leng F, Hinz R, Gentleman S, et al., 2023, Neuroinflammation is independently associated with brain network dysfunction in Alzheimer's disease, MOLECULAR PSYCHIATRY, Vol: 28, Pages: 1303-1311, ISSN: 1359-4184
- Author Web Link
- Cite
- Citations: 9
Schiappucci E, Bianchini F, Aguena M, et al., 2023, Measurement of the mean central optical depth of galaxy clusters via the pairwise kinematic Sunyaev-Zel'dovich effect with SPT-3G and des, Physical Review D, Vol: 107, ISSN: 2470-0010
We infer the mean optical depth of a sample of optically selected galaxy clusters from the Dark Energy Survey via the pairwise kinematic Sunyaev-Zel'dovich (KSZ) effect. The pairwise KSZ signal between pairs of clusters drawn from the Dark Energy Survey Year-3 cluster catalog is detected at 4.1σ in cosmic microwave background temperature maps from two years of observations with the SPT-3G camera on the South Pole Telescope. After cuts, there are 24,580 clusters in the ∼1,400 deg2 of the southern sky observed by both experiments. We infer the mean optical depth of the cluster sample with two techniques. The optical depth inferred from the pairwise KSZ signal is τ¯e=(2.97±0.73)×10-3, while that inferred from the thermal SZ signal is τ¯e=(2.51±0.55stat±0.15syst)×10-3. The two measures agree at 0.6σ. We perform a suite of systematic checks to test the robustness of the analysis.
Simon JD, Brown TM, Mutlu-Pakdil B, et al., 2023, Timing the r-process Enrichment of the Ultra-faint Dwarf Galaxy Reticulum II, Astrophysical Journal, Vol: 944, ISSN: 0004-637X
The ultra-faint dwarf galaxy Reticulum II (Ret II) exhibits a unique chemical evolution history, with 72 − 12 + 10 % of its stars strongly enhanced in r-process elements. We present deep Hubble Space Telescope photometry of Ret II and analyze its star formation history. As in other ultra-faint dwarfs, the color-magnitude diagram is best fit by a model consisting of two bursts of star formation. If we assume that the bursts were instantaneous, then the older burst occurred around the epoch of reionization, forming ∼80% of the stars in the galaxy, while the remainder of the stars formed ∼3 Gyr later. When the bursts are allowed to have nonzero durations, we obtain slightly better fits. The best-fitting model in this case consists of two bursts beginning before reionization, with approximately half the stars formed in a short (100 Myr) burst and the other half in a more extended period lasting 2.6 Gyr. Considering the full set of viable star formation history models, we find that 28% of the stars formed within 500 ± 200 Myr of the onset of star formation. The combination of the star formation history and the prevalence of r-process-enhanced stars demonstrates that the r-process elements in Ret II must have been synthesized early in its initial star-forming phase. We therefore constrain the delay time between the formation of the first stars in Ret II and the r-process nucleosynthesis to be less than 500 Myr. This measurement rules out an r-process source with a delay time of several Gyr or more, such as GW170817.
Chaussidon E, Yèche C, Palanque-Delabrouille N, et al., 2023, Target Selection and Validation of DESI Quasars, Astrophysical Journal, Vol: 944, ISSN: 0004-637X
The Dark Energy Spectroscopic Instrument (DESI) survey will measure large-scale structures using quasars as direct tracers of dark matter in the redshift range 0.9 < z < 2.1 and using Lyα forests in quasar spectra at z > 2.1. We present several methods to select candidate quasars for DESI, using input photometric imaging in three optical bands (g, r, z) from the DESI Legacy Imaging Surveys and two infrared bands (W1, W2) from the Wide-field Infrared Survey Explorer. These methods were extensively tested during the Survey Validation of DESI. In this paper, we report on the results obtained with the different methods and present the selection we optimized for the DESI main survey. The final quasar target selection is based on a random forest algorithm and selects quasars in the magnitude range of 16.5 < r < 23. Visual selection of ultra-deep observations indicates that the main selection consists of 71% quasars, 16% galaxies, 6% stars, and 7% inconclusive spectra. Using the spectra based on this selection, we build an automated quasar catalog that achieves a fraction of true QSOs higher than 99% for a nominal effective exposure time of ∼1000 s. With a 310 deg−2 target density, the main selection allows DESI to select more than 200 deg−2 quasars (including 60 deg−2 quasars with z > 2.1), exceeding the project requirements by 20%. The redshift distribution of the selected quasars is in excellent agreement with quasar luminosity function predictions.
Dey A, Najita JR, Koposov SE, et al., 2023, DESI Observations of the Andromeda Galaxy: Revealing the Immigration History of Our Nearest Neighbor, Astrophysical Journal, Vol: 944, ISSN: 0004-637X
We present Dark Energy Spectroscopic Instrument (DESI) observations of the inner halo of M31, which reveal the kinematics of a recent merger—a galactic immigration event—in exquisite detail. Of the 11,416 sources studied in 3.75 hr of on-sky exposure time, 7438 are M31 sources with well-measured radial velocities. The observations reveal intricate coherent kinematic structure in the positions and velocities of individual stars: streams, wedges, and chevrons. While hints of coherent structures have been previously detected in M31, this is the first time they have been seen with such detail and clarity in a galaxy beyond the Milky Way. We find clear kinematic evidence for shell structures in the Giant Stellar Stream, the Northeast Shelf, and Western Shelf regions. The kinematics are remarkably similar to the predictions of dynamical models constructed to explain the spatial morphology of the inner halo. The results are consistent with the interpretation that much of the substructure in the inner halo of M31 is produced by a single galactic immigration event 1-2 Gyr ago. Significant numbers of metal-rich stars ([Fe/H] > − 0.5) are present in all of the detected substructures, suggesting that the immigrating galaxy had an extended star formation history. We also investigate the ability of the shells and Giant Stellar Stream to constrain the gravitational potential of M31, and estimate the mass within a projected radius of 125 kpc to be log 10 M NFW ( < 125 kpc ) / M ⊙ = 11.80 − 0.10 + 0.12 . The results herald a new era in our ability to study stars on a galactic scale and the immigration histories of galaxies.
Chang C, Omori Y, Baxter EJ, et al., 2023, Joint analysis of Dark Energy Survey Year 3 data and CMB lensing and cosmological constraints, PHYSICAL REVIEW D, Vol: 107, ISSN: 2470-0010
- Author Web Link
- Cite
- Citations: 4
Abbott TMC, Aguena M, Alarcon A, et al., 2023, Joint analysis of Dark Energy Survey Year 3 data and CMB lensing from SPT and <i>Planck</i>. III. Combined cosmological constraints, PHYSICAL REVIEW D, Vol: 107, ISSN: 2470-0010
- Author Web Link
- Cite
- Citations: 8
Omori Y, Baxter EJ, Chang C, et al., 2023, Joint analysis of Dark Energy Survey Year 3 data and CMB lensing from SPT and Planck. I. Construction of CMB lensing maps and modeling choices, PHYSICAL REVIEW D, Vol: 107, ISSN: 2470-0010
- Author Web Link
- Cite
- Citations: 4
Morgan R, Nord B, Bechtol K, et al., 2023, DeepZipper. II. Searching for Lensed Supernovae in Dark Energy Survey Data with Deep Learning, Astrophysical Journal, Vol: 943, ISSN: 0004-637X
Gravitationally lensed supernovae (LSNe) are important probes of cosmic expansion, but they remain rare and difficult to find. Current cosmic surveys likely contain 5-10 LSNe in total while next-generation experiments are expected to contain several hundred to a few thousand of these systems. We search for these systems in observed Dark Energy Survey (DES) five year SN fields—10 3 sq. deg. regions of sky imaged in the griz bands approximately every six nights over five years. To perform the search, we utilize the DeepZipper approach: a multi-branch deep learning architecture trained on image-level simulations of LSNe that simultaneously learns spatial and temporal relationships from time series of images. We find that our method obtains an LSN recall of 61.13% and a false-positive rate of 0.02% on the DES SN field data. DeepZipper selected 2245 candidates from a magnitude-limited (m i < 22.5) catalog of 3,459,186 systems. We employ human visual inspection to review systems selected by the network and find three candidate LSNe in the DES SN fields.
Real CC, Binda KH, Thomsen MB, et al., 2023, Selecting the Best Animal Model of Parkinson's Disease for Your Research Purpose: Insight from <i>in vivo</i> PET Imaging Studies, CURRENT NEUROPHARMACOLOGY, Vol: 21, Pages: 1241-1272, ISSN: 1570-159X
O'Brien JT, Chouliaras L, Sultana J, et al., 2022, RENEWAL: REpurposing study to find NEW compounds with Activity for Lewy body dementia-an international Delphi consensus, ALZHEIMERS RESEARCH & THERAPY, Vol: 14
- Author Web Link
- Cite
- Citations: 6
Abareshi B, Aguilar J, Ahlen S, et al., 2022, Overview of the Instrumentation for the Dark Energy Spectroscopic Instrument, ASTRONOMICAL JOURNAL, Vol: 164, ISSN: 0004-6256
- Author Web Link
- Cite
- Citations: 48
Horsager J, Okkels N, Fedorova TD, et al., 2022, [18F]FEOBV positron emission tomography may not be a suitable method to measure parasympathetic denervation in patients with Parkinson's disease, PARKINSONISM & RELATED DISORDERS, Vol: 104, Pages: 21-25, ISSN: 1353-8020
Andersen OM, Bogh N, Landau AM, et al., 2022, A genetically modified minipig model for Alzheimer's disease with SORL1 haploinsufficiency, CELL REPORTS MEDICINE, Vol: 3, ISSN: 2666-3791
- Author Web Link
- Cite
- Citations: 4
Venkataraman A, Mansur A, Rizzo G, et al., 2022, Widespread cell stress and mitochondrial dysfunction occur in patients with early Alzheimer’s Disease, Science Translational Medicine, Vol: 14, Pages: 1-11, ISSN: 1946-6234
Cell stress and impaired oxidative phosphorylation are central to mechanisms of synaptic loss and neurodegeneration in the cellular pathology of Alzheimer’s disease (AD). In this study, we quantified the in vivo expression of the endoplasmic reticulum stress marker, sigma 1 receptor (S1R), using [11C]SA4503 PET, the mitochondrial complex I (MC1) with [18F]BCPP-EF and the pre-synaptic vesicular protein SV2A with [11C]UCB-J in 12 patients with early AD and in 16 cognitively normal controls. We integrated these molecular measures with assessments of regional brain volumes and cerebral blood flow (CBF) measured with magnetic resonance imaging (MRI) arterial spin labelling. Eight patients with AD were followed longitudinally to estimate the rate of change of the physiological and structural pathology markers with disease progression. The patients showed widespread increases in S1R (≤ 27%) and regional reduction in MC1 (≥ -28%) and SV2A (≥ -25%) radioligand binding, brain volume (≥ -23%), and CBF (≥ -26%). [18F]BCPP-EF PET MC1 binding (≥ -12%) and brain volumes (≥ -5%) showed progressive reductions over 12-18 months, suggesting that they both could be used as pharmacodynamic indicators in early-stage therapeutics trials. Associations of reduced MC1 and SV2A and increased S1R radioligand binding with reduced cognitive performance in AD, although exploratory, suggested a loss of metabolic functional reserve with disease. Our study thus provides in vivo evidence for widespread, clinically relevant cellular stress and bioenergetic abnormalities in early AD.
Lang AE, Siderowf AD, Macklin EA, et al., 2022, Trial of Cinpanemab in Early Parkinson's Disease, NEW ENGLAND JOURNAL OF MEDICINE, Vol: 387, Pages: 408-420, ISSN: 0028-4793
- Author Web Link
- Cite
- Citations: 77
Andersen KB, Hansen AK, Knudsen K, et al., 2022, Healthy brain aging assessed with [<SUP>18</SUP>F]FDG and [<SUP>11</SUP>C]UCB-J PET, NUCLEAR MEDICINE AND BIOLOGY, Vol: 112-113, Pages: 52-58, ISSN: 0969-8051
- Author Web Link
- Cite
- Citations: 6
Lokken M, Hložek R, Engelen AV, et al., 2022, Superclustering with the Atacama Cosmology Telescope and Dark Energy Survey. I. Evidence for Thermal Energy Anisotropy Using Oriented Stacking, Astrophysical Journal, Vol: 933, ISSN: 0004-637X
The cosmic web contains filamentary structure on a wide range of scales. On the largest scales, superclustering aligns multiple galaxy clusters along intercluster bridges, visible through their thermal Sunyaev-Zel'dovich signal in the cosmic microwave background. We demonstrate a new, flexible method to analyze the hot gas signal from multiscale extended structures. We use a Compton y-map from the Atacama Cosmology Telescope (ACT) stacked on redMaPPer cluster positions from the optical Dark Energy Survey (DES). Cutout images from the y-map are oriented with large-scale structure information from DES galaxy data such that the superclustering signal is aligned before being overlaid. We find evidence of an extended quadrupole moment of the stacked y signal at the 3.5σ level, demonstrating that the large-scale thermal energy surrounding galaxy clusters is anisotropically distributed. We compare our ACT × DES results with the Buzzard simulations, finding broad agreement. Using simulations, we highlight the promise of this novel technique for constraining the evolution of anisotropic, non-Gaussian structure using future combinations of microwave and optical surveys.
Lillethorup TP, Noer O, Alstrup AKO, et al., 2022, Spontaneous partial recovery of striatal dopaminergic uptake despite nigral cell loss in asymptomatic MPTP-lesioned female minipigs, NEUROTOXICOLOGY, Vol: 91, Pages: 166-176, ISSN: 0161-813X
- Author Web Link
- Cite
- Citations: 1
Mau S, Nadler EO, Wechsler RH, et al., 2022, Milky Way Satellite Census. IV. Constraints on Decaying Dark Matter from Observations of Milky Way Satellite Galaxies, Astrophysical Journal, Vol: 932, ISSN: 0004-637X
We use a recent census of the Milky Way (MW) satellite galaxy population to constrain the lifetime of particle dark matter (DM). We consider two-body decaying dark matter (DDM) in which a heavy DM particle decays with lifetime τ comparable to the age of the universe to a lighter DM particle (with mass splitting ϵ) and to a dark radiation species. These decays impart a characteristic "kick velocity,"V kick = ϵ c, on the DM daughter particles, significantly depleting the DM content of low-mass subhalos and making them more susceptible to tidal disruption. We fit the suppression of the present-day DDM subhalo mass function (SHMF) as a function of τ and V kick using a suite of high-resolution zoom-in simulations of MW-mass halos, and we validate this model on new DDM simulations of systems specifically chosen to resemble the MW. We implement our DDM SHMF predictions in a forward model that incorporates inhomogeneities in the spatial distribution and detectability of MW satellites and uncertainties in the mapping between galaxies and DM halos, the properties of the MW system, and the disruption of subhalos by the MW disk using an empirical model for the galaxy-halo connection. By comparing to the observed MW satellite population, we conservatively exclude DDM models with τ < 18 Gyr (29 Gyr) for V kick = 20 kms-1 (40 kms-1) at 95% confidence. These constraints are among the most stringent and robust small-scale structure limits on the DM particle lifetime and strongly disfavor DDM models that have been proposed to alleviate the Hubble and S 8 tensions.
Sigurdsson HP, Yarnall AJ, Galna B, et al., 2022, Gait-Related Metabolic Covariance Networks at Rest in Parkinson's Disease, MOVEMENT DISORDERS, Vol: 37, Pages: 1222-1234, ISSN: 0885-3185
- Author Web Link
- Cite
- Citations: 2
Somboonpanyakul T, McDonald M, Noble A, et al., 2022, The Evolution of AGN Activity in Brightest Cluster Galaxies, Astronomical Journal, Vol: 163, ISSN: 0004-6256
We present the results of an analysis of Wide-field Infrared Survey Explorer (WISE) observations of the full 2500 deg2 South Pole Telescope (SPT)-Sunyaev-Zel'dovich cluster sample. We describe a process for identifying active galactic nuclei (AGN) in brightest cluster galaxies (BCGs) based on WISE mid-IR color and redshift. Applying this technique to the BCGs of the SPT-SZ sample, we calculate the AGN-hosting BCG fraction, which is defined as the fraction of BCGs hosting bright central AGNs over all possible BCGs. Assuming an evolving single-burst stellar population model, we find statistically significant evidence (>99.9%) for a mid-IR excess at high redshift compared to low redshift, suggesting that the fraction of AGN-hosting BCGs increases with redshift over the range of 0 < z < 1.3. The best-fit redshift trend of the AGN-hosting BCG fraction has the form (1 + z)4.1±1.0. These results are consistent with previous studies in galaxy clusters as well as as in field galaxies. One way to explain this result is that member galaxies at high redshift tend to have more cold gas. While BCGs in nearby galaxy clusters grow mostly by dry mergers with cluster members, leading to no increase in AGN activity, BCGs at high redshift could primarily merge with gas-rich satellites, providing fuel for feeding AGNs. If this observed increase in AGN activity is linked to gas-rich mergers rather than ICM cooling, we would expect to see an increase in scatter in the P cav versus L cool relation at z > 1. Last, this work confirms that the runaway cooling phase, as predicted by the classical cooling-flow model, in the Phoenix cluster is extremely rare and most BCGs have low (relative to Eddington) black hole accretion rates.
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.