We have reprocessed over 100 terabytes of single-exposure Wide-field Infrared Survey Explorer (WISE)/NEOWISE images to create the deepest ever full-sky maps at 3-5 microns. We include all publicly ...available W1 and W2 imaging-a total of ∼8 million exposures in each band-from ∼37 months of observations spanning 2010 January to 2015 December. Our coadds preserve the native WISE resolution and typically incorporate ∼3× more input frames than those of the AllWISE Atlas stacks. Our coadds are designed to enable deep forced photometry, in particular for the Dark Energy Camera Legacy Survey (DECaLS) and Mayall z-Band Legacy Survey (MzLS), both of which are being used to select targets for the Dark Energy Spectroscopic Instrument. We describe newly introduced processing steps aimed at leveraging added redundancy to remove artifacts, with the intent of facilitating uniform target selection and searches for rare/exotic objects (e.g., high-redshift quasars and distant galaxy clusters). Forced photometry depths achieved with these coadds extend 0.56 (0.46) magnitudes deeper in W1 (W2) than is possible with only pre-hibernation WISE imaging.
Time-resolved WISE/NEOWISE Coadds Meisner, A. M.; Lang, D.; Schlegel, D. J.
The Astronomical journal,
08/2018, Letnik:
156, Številka:
2
Journal Article
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We have used the first ∼3 years of 3.4 m (W1) and 4.6 m (W2) observations from the WISE and NEOWISE missions to create a full-sky set of time-resolved coadds. As a result of the WISE survey strategy, ...a typical sky location is visited every six months and is observed during 12 exposures per visit, with these exposures spanning a ∼1 day time interval. We have stacked the exposures within such ∼1 day intervals to produce one coadd per band per visit-that is, one coadd every six months at a given position on the sky in each of W1 and W2. For most parts of the sky, we have generated six epochal coadds per band, with one visit during the fully cryogenic WISE mission, one visit during NEOWISE, and then, after a 33-month gap, four more visits during the NEOWISE-Reactivation mission phase. These coadds are suitable for studying long-timescale mid-infrared variability and measuring motions to ∼1.3 mag fainter than the single-exposure detection limit. In most sky regions, our coadds span a 5.5-year time period and therefore provide a >10× enhancement in time baseline relative to that available for the AllWISE catalog's apparent motion measurements. As such, the signature application of these new coadds is expected to be motion-based identification of relatively faint brown dwarfs, especially those cold enough to remain undetected by Gaia.
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a novel transit radio telescope operating across the 400-800 MHz band. CHIME is composed of four 20 m × 100 m semicylindrical paraboloid ...reflectors, each of which has 256 dual-polarization feeds suspended along its axis, giving it a 200 deg2 field of view. This, combined with wide bandwidth, high sensitivity, and a powerful correlator, makes CHIME an excellent instrument for the detection of fast radio bursts (FRBs). The CHIME Fast Radio Burst Project (CHIME/FRB) will search beam-formed, high time and frequency resolution data in real time for FRBs in the CHIME field of view. Here we describe the CHIME/FRB back end, including the real-time FRB search and detection software pipeline, as well as the planned offline analyses. We estimate a CHIME/FRB detection rate of 2-42 FRBs sky-1 day-1 normalizing to the rate estimated at 1.4 GHz by Vander Wiel et al. Likely science outcomes of CHIME/FRB are also discussed. CHIME/FRB is currently operational in a commissioning phase, with science operations expected to commence in the latter half of 2018.
This article introduces a package that provides interactive and programmatic access to the FishBase repository. This package allows interaction with data on over 30 000 fish species in the rich ...statistical computing environment, R. This direct, scriptable interface to FishBase data enables better discovery and integration essential for large‐scale comparative analyses. This article provides several examples to illustrate how the package works, and how it can be integrated into phylogenetics packages such as ape and geiger.
Ecosystem services research has become a major academic field, drawing in various academic disciplines, perspectives, and research approaches. The multifaceted concept of “ecosystem services” ...includes a normative component, which has strong implicit links to the notion of sustainability. Yet, how ecosystem services research relates to sustainability has received little attention. We reviewed the current state of research on ecosystem services, and examined whether the concept's original motivation has allowed it to act as an effective boundary object for the integration of the diverse knowledge related to sustainability. A full-text, multivariate statistical analysis of 1388 peer-reviewed publications on ecosystem services from 1997 to 2011 revealed a rapidly growing but fragmented body of research, which has emphasized the development of descriptive understandings of human–nature interactions. Future challenges for the ecosystem services concept include greater integration of currently fragmented knowledge domains and stronger engagement with the concept's normative foundations.
•Full-text analysis of 1388 publications revealed a fragmented body of research.•Ecosystem services research has coalesced around nine separate research clusters.•Clusters have distinct conceptual vocabulary, but all emphasize system knowledge.•To move beyond heuristic metaphors research must address normative issues.
Ammonia-oxidizing archaea are ubiquitous in marine and terrestrial environments and now thought to be significant contributors to carbon and nitrogen cycling. The isolation of Candidatus ..."Nitrosopumilus maritimus" strain SCM1 provided the opportunity for linking its chemolithotrophic physiology with a genomic inventory of the globally distributed archaea. Here we report the 1,645,259-bp closed genome of strain SCM1, revealing highly copper-dependent systems for ammonia oxidation and electron transport that are distinctly different from known ammonia-oxidizing bacteria. Consistent with in situ isotopic studies of marine archaea, the genome sequence indicates N. maritimus grows autotrophically using a variant of the 3-hydroxypropionate/4-hydroxybutryrate pathway for carbon assimilation, while maintaining limited capacity for assimilation of organic carbon. This unique instance of archaeal biosynthesis of the osmoprotectant ectoine and an unprecedented enrichment of multicopper oxidases, thioredoxin-like proteins, and transcriptional regulators points to an organism responsive to environmental cues and adapted to handling reactive copper and nitrogen species that likely derive from its distinctive biochemistry. The conservation of N. maritimus gene content and organization within marine metagenomes indicates that the unique physiology of these specialized oligophiles may play a significant role in the biogeochemical cycles of carbon and nitrogen.
Abstract
We have conducted a search for new strong gravitational lensing systems in the Dark Energy Spectroscopic Instrument Legacy Imaging Surveys’ Data Release 8. We use deep residual neural ...networks, building on previous work presented by Huang et al. These surveys together cover approximately one-third of the sky visible from the Northern Hemisphere, reaching a
z
-band AB magnitude of ∼22.5. We compile a training sample that consists of known lensing systems as well as non-lenses in the Legacy Surveys and the Dark Energy Survey. After applying our trained neural networks to the survey data, we visually inspect and rank images with probabilities above a threshold. Here we present 1210 new strong lens candidates.
We perform a semi-automated search for strong gravitational lensing systems in the 9000 deg2 Dark Energy Camera Legacy Survey (DECaLS), part of the Dark Energy Spectroscopic Instrument Legacy Imaging ...Surveys. The combination of the depth and breadth of these surveys are unparalleled at this time, making them particularly suitable for discovering new strong gravitational lensing systems. We adopt the deep residual neural network architecture developed by Lanusse et al. for the purpose of finding strong lenses in photometric surveys. We compile a training sample that consists of known lensing systems in the Legacy Surveys and the Dark Energy Survey as well as non-lenses in the footprint of DECaLS. In this paper we show the results of applying our trained neural network to the cutout images centered on galaxies typed as ellipticals in DECaLS. The images that receive the highest scores (probabilities) are visually inspected and ranked. Here we present 335 candidate strong lensing systems, identified for the first time.
Models for double parton distributions that are realistic and consistent with theoretical constraints are crucial for a reliable description of double parton scattering. We show how an ansatz that ...has the correct behaviour in the limit of small transverse distance between the partons can be improved step by step, such as to fulfil the sum rules for double parton distributions with an accuracy around 10%.
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