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At least 1,657 records · Page 92
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Photometric classification of Hyper Suprime-Cam transients using machine learning

Abstract The advancement of technology has resulted in a rapid increase in supernova (SN) discoveries. The Subaru/Hyper Suprime-Cam (HSC) transient survey, conducted from fall 2016 through spring 2017, yielded 1824 SN candidates. This gave rise to the need for fast type classification for spectroscopic follow-up and prompted us to develop a machine learning algorithm using a deep neural network with highway layers. This algorithm is trained by actual observed cadence and filter combinations such that we can directly input the observed data array without any interpretation. We tested our model with a dataset from the LSST classification challenge (Deep Drilling Field). Our classifier scores an area under the curve (AUC) of 0.996 for binary classification (SN Ia or non-SN Ia) and 95.3% accuracy for three-class classification (SN Ia, SN Ibc, or SN II). Application of our binary classification to HSC transient data yields an AUC score of 0.925. With two weeks of HSC data since the first detection, this classifier achieves 78.1% accuracy for binary classification, and the accuracy increases to 84.2% with the full dataset. This paper discusses the potential use of machine learning for SN type classification purposes.

Takahashi, Ichiro↗
DOE OSTI2024

The Dark Energy Survey: Cosmology Results with ∼1500 New High-redshift Type Ia Supernovae Using the Full 5 yr Data Set

Abstract We present cosmological constraints from the sample of Type Ia supernovae (SNe Ia) discovered and measured during the full 5 yr of the Dark Energy Survey (DES) SN program. In contrast to most previous cosmological samples, in which SNe are classified based on their spectra, we classify the DES SNe using a machine learning algorithm applied to their light curves in four photometric bands. Spectroscopic redshifts are acquired from a dedicated follow-up survey of the host galaxies. After accounting for the likelihood of each SN being an SN Ia, we find 1635 DES SNe in the redshift range 0.10 < z < 1.13 that pass quality selection criteria sufficient to constrain cosmological parameters. This quintuples the number of high-quality z > 0.5 SNe compared to the previous leading compilation of Pantheon+ and results in the tightest cosmological constraints achieved by any SN data set to date. To derive cosmological constraints, we combine the DES SN data with a high-quality external low-redshift sample consisting of 194 SNe Ia spanning 0.025 < z < 0.10. Using SN data alone and including systematic uncertainties, we find Ω M = 0.352 ± 0.017 in flat ΛCDM. SN data alone now require acceleration ( q 0 < 0 in ΛCDM) with over 5 σ confidence. We find ( Ω M , w ) = ( 0.264 − 0.096 + 0.074 , − 0.80 − 0.16 + 0.14 ) in flat w CDM. For flat w 0 w a CDM, we find ( Ω M , w 0 , w a ) = ( 0.495 − 0.043 + 0.033 , − 0.36 − 0.30 + 0.36 , − 8.8 − 4.5 + 3.7 ) , consistent with a constant equation of state to within ∼2 σ . Including Planck cosmic microwave background, Sloan Digital Sky Survey baryon acoustic oscillation, and DES 3 × 2pt data gives (Ω M , w ) = (0.321 ± 0.007, −0.941 ± 0.026). In all cases, dark energy is consistent with a cosmological constant to within ∼2 σ . Systematic errors on cosmological parameters are subdominant compared to statistical errors; these results thus pave the way for future photometrically classified SN analyses.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Materials Data on ZrSnRh by Materials Project

RhZrSn crystallizes in the hexagonal P-62c space group. The structure is three-dimensional. Zr is bonded in a 11-coordinate geometry to five Rh and six equivalent Sn atoms. There are a spread of Zr–Rh bond distances ranging from 2.85–3.01 Å. There are a spread of Zr–Sn bond distances ranging from 3.07–3.25 Å. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 9-coordinate geometry to three equivalent Zr and six equivalent Sn atoms. All Rh–Sn bond lengths are 2.71 Å. In the second Rh site, Rh is bonded in a 9-coordinate geometry to six equivalent Zr and three equivalent Sn atoms. All Rh–Sn bond lengths are 2.75 Å. Sn is bonded in a 10-coordinate geometry to six equivalent Zr and four Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NbSn2 by Materials Project

NbSn2 is Khatyrkite-like structured and crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. Nb is bonded in a 10-coordinate geometry to two equivalent Nb and eight Sn atoms. Both Nb–Nb bond lengths are 2.87 Å. There are a spread of Nb–Sn bond distances ranging from 2.89–2.99 Å. There are two inequivalent Sn sites. In the first Sn site, Sn is bonded in a 4-coordinate geometry to four equivalent Nb atoms. In the second Sn site, Sn is bonded in a 7-coordinate geometry to four equivalent Nb atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HoSnRh by Materials Project

HoRhSn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Ho is bonded in a 11-coordinate geometry to five Rh and six equivalent Sn atoms. There are four shorter (2.99 Å) and one longer (3.08 Å) Ho–Rh bond lengths. There are two shorter (3.15 Å) and four longer (3.30 Å) Ho–Sn bond lengths. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 9-coordinate geometry to three equivalent Ho and six equivalent Sn atoms. All Rh–Sn bond lengths are 2.76 Å. In the second Rh site, Rh is bonded in a 9-coordinate geometry to six equivalent Ho and three equivalent Sn atoms. All Rh–Sn bond lengths are 2.84 Å. Sn is bonded in a 10-coordinate geometry to six equivalent Ho and four Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YbSnRh by Materials Project

YbRhSn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Yb is bonded in a 11-coordinate geometry to five Rh and six equivalent Sn atoms. There are one shorter (2.99 Å) and four longer (3.03 Å) Yb–Rh bond lengths. There are two shorter (3.19 Å) and four longer (3.34 Å) Yb–Sn bond lengths. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 9-coordinate geometry to three equivalent Yb and six equivalent Sn atoms. All Rh–Sn bond lengths are 2.80 Å. In the second Rh site, Rh is bonded in a 9-coordinate geometry to six equivalent Yb and three equivalent Sn atoms. All Rh–Sn bond lengths are 2.75 Å. Sn is bonded in a 10-coordinate geometry to six equivalent Yb and four Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TmSnRh by Materials Project

TmRhSn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Tm is bonded in a 11-coordinate geometry to five Rh and six equivalent Sn atoms. There are four shorter (2.97 Å) and one longer (3.06 Å) Tm–Rh bond lengths. There are two shorter (3.13 Å) and four longer (3.28 Å) Tm–Sn bond lengths. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 9-coordinate geometry to three equivalent Tm and six equivalent Sn atoms. All Rh–Sn bond lengths are 2.75 Å. In the second Rh site, Rh is bonded in a 9-coordinate geometry to six equivalent Tm and three equivalent Sn atoms. All Rh–Sn bond lengths are 2.82 Å. Sn is bonded in a 10-coordinate geometry to six equivalent Tm and four Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CeSnRh by Materials Project

CeRhSn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Ce is bonded in a 11-coordinate geometry to five Rh and six equivalent Sn atoms. There are four shorter (3.04 Å) and one longer (3.10 Å) Ce–Rh bond lengths. There are two shorter (3.23 Å) and four longer (3.39 Å) Ce–Sn bond lengths. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 9-coordinate geometry to three equivalent Ce and six equivalent Sn atoms. All Rh–Sn bond lengths are 2.78 Å. In the second Rh site, Rh is bonded in a 9-coordinate geometry to six equivalent Ce and three equivalent Sn atoms. All Rh–Sn bond lengths are 2.85 Å. Sn is bonded in a 10-coordinate geometry to six equivalent Ce and four Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrSnRh by Materials Project

PrRhSn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Pr is bonded in a 11-coordinate geometry to five Rh and six equivalent Sn atoms. There are four shorter (3.09 Å) and one longer (3.11 Å) Pr–Rh bond lengths. There are two shorter (3.30 Å) and four longer (3.43 Å) Pr–Sn bond lengths. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 9-coordinate geometry to three equivalent Pr and six equivalent Sn atoms. All Rh–Sn bond lengths are 2.82 Å. In the second Rh site, Rh is bonded in a 9-coordinate geometry to six equivalent Pr and three equivalent Sn atoms. All Rh–Sn bond lengths are 2.88 Å. Sn is bonded in a 12-coordinate geometry to six equivalent Pr and four Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaSnPd by Materials Project

LaPdSn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. La is bonded in a 11-coordinate geometry to five Pd and six equivalent Sn atoms. There are four shorter (3.15 Å) and one longer (3.21 Å) La–Pd bond lengths. There are two shorter (3.36 Å) and four longer (3.50 Å) La–Sn bond lengths. There are two inequivalent Pd sites. In the first Pd site, Pd is bonded in a 9-coordinate geometry to six equivalent La and three equivalent Sn atoms. All Pd–Sn bond lengths are 2.97 Å. In the second Pd site, Pd is bonded in a 9-coordinate geometry to three equivalent La and six equivalent Sn atoms. All Pd–Sn bond lengths are 2.85 Å. Sn is bonded in a 12-coordinate geometry to six equivalent La and four Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TbZnSn by Materials Project

TbZnSn crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Tb sites. In the first Tb site, Tb is bonded in a 12-coordinate geometry to six equivalent Zn and six equivalent Sn atoms. All Tb–Zn bond lengths are 2.98 Å. All Tb–Sn bond lengths are 3.40 Å. In the second Tb site, Tb is bonded to six equivalent Sn atoms to form edge-sharing TbSn6 octahedra. All Tb–Sn bond lengths are 3.18 Å. Zn is bonded in a 6-coordinate geometry to three equivalent Tb and three equivalent Sn atoms. All Zn–Sn bond lengths are 2.71 Å. Sn is bonded in a 6-coordinate geometry to six Tb and three equivalent Zn atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaSnPt by Materials Project

LaPtSn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. La is bonded in a 11-coordinate geometry to five Pt and six equivalent Sn atoms. There are four shorter (3.14 Å) and one longer (3.20 Å) La–Pt bond lengths. There are two shorter (3.35 Å) and four longer (3.49 Å) La–Sn bond lengths. There are two inequivalent Pt sites. In the first Pt site, Pt is bonded in a 9-coordinate geometry to six equivalent La and three equivalent Sn atoms. All Pt–Sn bond lengths are 2.96 Å. In the second Pt site, Pt is bonded in a 9-coordinate geometry to three equivalent La and six equivalent Sn atoms. All Pt–Sn bond lengths are 2.85 Å. Sn is bonded in a 10-coordinate geometry to six equivalent La and four Pt atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sn4Au by Materials Project

AuSn4 crystallizes in the orthorhombic Aea2 space group. The structure is two-dimensional and consists of two AuSn4 sheets oriented in the (0, 1, 0) direction. Au is bonded in a 8-coordinate geometry to eight Sn atoms. There are a spread of Au–Sn bond distances ranging from 2.89–2.97 Å. There are two inequivalent Sn sites. In the first Sn site, Sn is bonded in a distorted water-like geometry to two equivalent Au atoms. In the second Sn site, Sn is bonded in a distorted water-like geometry to two equivalent Au atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sn2Au by Materials Project

AuSn2 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. Au is bonded to six Sn atoms to form a mixture of edge and corner-sharing AuSn6 octahedra. The corner-sharing octahedra tilt angles range from 48–66°. There are a spread of Au–Sn bond distances ranging from 2.79–2.89 Å. There are two inequivalent Sn sites. In the first Sn site, Sn is bonded in a 3-coordinate geometry to three equivalent Au atoms. In the second Sn site, Sn is bonded in a 3-coordinate geometry to three equivalent Au atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ScSnPd by Materials Project

ScPdSn crystallizes in the hexagonal P-62c space group. The structure is three-dimensional. Sc is bonded in a 11-coordinate geometry to five Pd and six equivalent Sn atoms. There are a spread of Sc–Pd bond distances ranging from 2.88–3.03 Å. There are a spread of Sc–Sn bond distances ranging from 3.09–3.26 Å. There are two inequivalent Pd sites. In the first Pd site, Pd is bonded in a 9-coordinate geometry to three equivalent Sc and six equivalent Sn atoms. All Pd–Sn bond lengths are 2.75 Å. In the second Pd site, Pd is bonded in a 9-coordinate geometry to six equivalent Sc and three equivalent Sn atoms. All Pd–Sn bond lengths are 2.77 Å. Sn is bonded in a 10-coordinate geometry to six equivalent Sc and four Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ScSnPt by Materials Project

ScPtSn crystallizes in the hexagonal P-62c space group. The structure is three-dimensional. Sc is bonded in a 11-coordinate geometry to five Pt and six equivalent Sn atoms. There are a spread of Sc–Pt bond distances ranging from 2.87–3.05 Å. There are a spread of Sc–Sn bond distances ranging from 3.10–3.27 Å. There are two inequivalent Pt sites. In the first Pt site, Pt is bonded in a 9-coordinate geometry to three equivalent Sc and six equivalent Sn atoms. All Pt–Sn bond lengths are 2.75 Å. In the second Pt site, Pt is bonded in a 9-coordinate geometry to six equivalent Sc and three equivalent Sn atoms. All Pt–Sn bond lengths are 2.75 Å. Sn is bonded in a 10-coordinate geometry to six equivalent Sc and four Pt atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CeSnPd by Materials Project

CePdSn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Ce is bonded in a 11-coordinate geometry to five Pd and six equivalent Sn atoms. There are four shorter (3.11 Å) and one longer (3.15 Å) Ce–Pd bond lengths. There are two shorter (3.30 Å) and four longer (3.45 Å) Ce–Sn bond lengths. There are two inequivalent Pd sites. In the first Pd site, Pd is bonded in a 9-coordinate geometry to six equivalent Ce and three equivalent Sn atoms. All Pd–Sn bond lengths are 2.90 Å. In the second Pd site, Pd is bonded in a 9-coordinate geometry to three equivalent Ce and six equivalent Sn atoms. All Pd–Sn bond lengths are 2.84 Å. Sn is bonded in a 10-coordinate geometry to six equivalent Ce and four Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on USnRu by Materials Project

URuSn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. U is bonded in a 11-coordinate geometry to five Ru and six equivalent Sn atoms. There are four shorter (2.99 Å) and one longer (3.04 Å) U–Ru bond lengths. There are two shorter (3.16 Å) and four longer (3.34 Å) U–Sn bond lengths. There are two inequivalent Ru sites. In the first Ru site, Ru is bonded in a 9-coordinate geometry to three equivalent U and six equivalent Sn atoms. All Ru–Sn bond lengths are 2.74 Å. In the second Ru site, Ru is bonded in a 9-coordinate geometry to six equivalent U and three equivalent Sn atoms. All Ru–Sn bond lengths are 2.78 Å. Sn is bonded in a 12-coordinate geometry to six equivalent U and four Ru atoms.

36 MATERIALS SCIENCE↗