Studying Type II supernovae as cosmological standard candles using the Dark Energy Survey

ABSTRACT Despite vast improvements in the measurement of the cosmological parameters, the nature of dark energy and an accurate value of the Hubble constant (H0) in the Hubble–Lemaître law remain unknown. To break the current impasse, it is necessary to develop as many independent techniques as possible, such as the use of Type II supernovae (SNe II). The goal of this paper is to demonstrate the utility of SNe II for deriving accurate extragalactic distances, which will be an asset for the next generation of telescopes where more-distant SNe II will be discovered. More specifically, we present a sample from the Dark Energy Survey Supernova Program (DES-SN) consisting of 15 SNe II with photometric and spectroscopic information spanning a redshift range up to 0.35. Combining our DES SNe with publicly available samples, and using the standard candle method (SCM), we construct the largest available Hubble diagram with SNe II in the Hubble flow (70 SNe II) and find an observed dispersion of 0.27 mag. We demonstrate that adding a colour term to the SN II standardization does not reduce the scatter in the Hubble diagram. Although SNe II are viable as distance indicators, this work points out important issues for improving their utility as independent extragalactic beacons: find new correlations, define a more standard subclass of SNe II, construct new SN II templates, and dedicate more observing time to high-redshift SNe II. Finally, for the first time, we perform simulations to estimate the redshift-dependent distance-modulus bias due to selection effects.

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First cosmology results using Type IA supernovae from the dark energy survey: effects of chromatic corrections to supernova photometry on measurements of cosmological parameters

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz619 ◽

2019 ◽

Vol 485 (4) ◽

pp. 5329-5344 ◽

Cited By ~ 8

Author(s):

J Lasker ◽

R Kessler ◽

D Scolnic ◽

D Brout ◽

D L Burke ◽

...

Keyword(s):

Dark Energy ◽

Cosmological Parameters ◽

Critical Density ◽

Transmission Function ◽

Type Ia Supernovae ◽

Distance Modulus ◽

Dark Energy Survey ◽

Type Ia ◽

Ia Supernovae ◽

Energy Survey

Abstract Calibration uncertainties have been the leading systematic uncertainty in recent analyses using Type Ia supernovae (SNe Ia) to measure cosmological parameters. To improve the calibration, we present the application of spectral energy distribution-dependent ‘chromatic corrections’ to the SN light-curve photometry from the Dark Energy Survey (DES). These corrections depend on the combined atmospheric and instrumental transmission function for each exposure, and they affect photometry at the 0.01 mag (1 per cent) level, comparable to systematic uncertainties in calibration and photometry. Fitting our combined DES and low-z SN Ia sample with baryon acoustic oscillation (BAO) and cosmic microwave background (CMB) priors for the cosmological parameters Ωm (the fraction of the critical density of the universe comprised of matter) and w (the dark energy equation of state parameter), we compare those parameters before and after applying the corrections. We find the change in w and Ωm due to not including chromatic corrections is −0.002 and 0.000, respectively, for the DES-SN3YR sample with BAO and CMB priors, consistent with a larger DES-SN3YR-like simulation, which has a w-change of 0.0005 with an uncertainty of 0.008 and an Ωm change of 0.000 with an uncertainty of 0.002. However, when considering samples on individual CCDs we find large redshift-dependent biases (∼0.02 in distance modulus) for SN distances.

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Mapping the universe with dark energy survey

International Journal of Modern Physics A ◽

10.1142/s0217751x1845015x ◽

2018 ◽

Vol 33 (34) ◽

pp. 1845015

Author(s):

Dragan Huterer

Keyword(s):

Dark Energy ◽

Large Scale ◽

Complex Analysis ◽

Cosmological Parameters ◽

Hubble Constant ◽

Current Status ◽

Accelerating Universe ◽

Dark Energy Survey ◽

Energy Survey ◽

The Universe

First, I summarize the current status of dark energy, including methods to use data to separate between general-relativity and modified-gravity scenarios for the accelerating universe. Then, I discuss recent results from the Dark Energy Survey, currently the world’s leading experiment mapping large-scale structure in the universe. Year-1 DES analysis performed in 2017 included the combination of galaxy clustering, cosmic shear, and their cross-correlation to impose constraints on key cosmological parameters, while upcoming Year-3 and -5 analyses will dramatically improve those constraints. I discuss some of the challenges in this complex analysis, its results, and the more general path forward toward better understanding of dark matter and dark energy in the universe. I also comment on the foremost tension in the field of cosmology today: between local measurements of the Hubble constant from type Ia supernovae, and global measurements from the cosmic microwave background anisotropies.

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First cosmological results using Type Ia supernovae from the Dark Energy Survey: measurement of the Hubble constant

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz978 ◽

2019 ◽

Vol 486 (2) ◽

pp. 2184-2196 ◽

Cited By ~ 62

Author(s):

E Macaulay ◽

R C Nichol ◽

D Bacon ◽

D Brout ◽

T M Davis ◽

...

Keyword(s):

Dark Energy ◽

Hubble Constant ◽

Type Ia Supernovae ◽

Distance Measurements ◽

Dark Energy Survey ◽

Systematic Uncertainties ◽

Type Ia ◽

Ia Supernovae ◽

Energy Survey ◽

Inverse Distance

ABSTRACT We present an improved measurement of the Hubble constant (H0) using the ‘inverse distance ladder’ method, which adds the information from 207 Type Ia supernovae (SNe Ia) from the Dark Energy Survey (DES) at redshift 0.018 < z < 0.85 to existing distance measurements of 122 low-redshift (z < 0.07) SNe Ia (Low-z) and measurements of Baryon Acoustic Oscillations (BAOs). Whereas traditional measurements of H0 with SNe Ia use a distance ladder of parallax and Cepheid variable stars, the inverse distance ladder relies on absolute distance measurements from the BAOs to calibrate the intrinsic magnitude of the SNe Ia. We find H0 = 67.8 ± 1.3 km s−1 Mpc−1 (statistical and systematic uncertainties, 68 per cent confidence). Our measurement makes minimal assumptions about the underlying cosmological model, and our analysis was blinded to reduce confirmation bias. We examine possible systematic uncertainties and all are below the statistical uncertainties. Our H0 value is consistent with estimates derived from the Cosmic Microwave Background assuming a ΛCDM universe.

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Cosmic Bayes. Datasets and priors in the hunt for dark energy

European Journal for Philosophy of Science ◽

10.1007/s13194-020-00338-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Michela Massimi

Keyword(s):

Parameter Estimation ◽

Dark Energy ◽

Model Selection ◽

Bayesian Methods ◽

Cosmological Parameters ◽

Observational Cosmology ◽

Dark Energy Survey ◽

Bayesian Priors ◽

Energy Survey ◽

And Task

AbstractBayesian methods are ubiquitous in contemporary observational cosmology. They enter into three main tasks: (I) cross-checking datasets for consistency; (II) fixing constraints on cosmological parameters; and (III) model selection. This article explores some epistemic limits of using Bayesian methods. The first limit concerns the degree of informativeness of the Bayesian priors and an ensuing methodological tension between task (I) and task (II). The second limit concerns the choice of wide flat priors and related tension between (II) parameter estimation and (III) model selection. The Dark Energy Survey (DES) and its recent Year 1 results illustrate both these limits concerning the use of Bayesianism.

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A Statistical Standard Siren Measurement of the Hubble Constant from the LIGO/Virgo Gravitational Wave Compact Object Merger GW190814 and Dark Energy Survey Galaxies

The Astrophysical Journal ◽

10.3847/2041-8213/abaeff ◽

2020 ◽

Vol 900 (2) ◽

pp. L33 ◽

Cited By ~ 1

Author(s):

A. Palmese ◽

J. deVicente ◽

M. E. S. Pereira ◽

J. Annis ◽

W. Hartley ◽

...

Keyword(s):

Dark Energy ◽

Gravitational Wave ◽

Compact Object ◽

Hubble Constant ◽

Dark Energy Survey ◽

Energy Survey

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On building a cluster watchlist for identifying strongly lensed supernovae, gravitational waves and kilonovae

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1274 ◽

2020 ◽

Vol 495 (2) ◽

pp. 1666-1671 ◽

Cited By ~ 2

Author(s):

Dan Ryczanowski ◽

Graham P Smith ◽

Matteo Bianconi ◽

Richard Massey ◽

Andrew Robertson ◽

...

Keyword(s):

Dark Energy ◽

Gravitational Waves ◽

Lower Limit ◽

High Redshift ◽

Early Data ◽

Source Plane ◽

Dark Energy Survey ◽

Strong Lensing ◽

Cluster Properties ◽

Energy Survey

ABSTRACT Motivated by discovering strongly lensed supernovae, gravitational waves, and kilonovae in the 2020s, we investigate whether to build a watchlist of clusters based on observed cluster properties (i.e. lens-plane selection) or on the detectability of strongly lensed background galaxies (i.e. source-plane selection). First, we estimate the fraction of high-redshift transient progenitors that reside in galaxies that are themselves too faint to be detected as being strongly lensed. We find ∼15–50 per cent of transient progenitors reside in z = 1 − 2 galaxies too faint to be detected in surveys that reach AB ≃ 23, such as the Dark Energy Survey. This falls to ≲10 per cent at depths that will be probed by early data releases of LSST (AB ≃ 25). Secondly, we estimate a conservative lower limit on the fraction of strong-lensing clusters that will be missed by magnitude-limited searches for multiply imaged galaxies and giant arcs due to the faintness of such images. We find that DES-like surveys will miss ∼75 per cent of 1015 M⊙ strong-lensing clusters, rising to ∼100 per cent of 1014 M⊙ clusters. Deeper surveys, such as LSST, will miss ∼40 per cent at 1015 M⊙ and ∼95 per cent at 1014 M⊙. Our results motivate building a cluster watchlist for strongly lensed transients that includes those found by the lens-plane selection.

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Superluminous supernovae from the Dark Energy Survey

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1321 ◽

2019 ◽

Vol 487 (2) ◽

pp. 2215-2241 ◽

Cited By ~ 19

Author(s):

C R Angus ◽

M Smith ◽

M Sullivan ◽

C Inserra ◽

P Wiseman ◽

...

Keyword(s):

Dark Energy ◽

Light Curve ◽

Luminosity Function ◽

High Redshift ◽

Absolute Magnitude ◽

Light Curves ◽

Evolutionary Time ◽

Dark Energy Survey ◽

Monte Carlo Search ◽

Energy Survey

ABSTRACT We present a sample of 21 hydrogen-free superluminous supernovae (SLSNe-I) and one hydrogen-rich SLSN (SLSN-II) detected during the five-year Dark Energy Survey (DES). These SNe, located in the redshift range 0.220 < z < 1.998, represent the largest homogeneously selected sample of SLSN events at high redshift. We present the observed g, r, i, z light curves for these SNe, which we interpolate using Gaussian processes. The resulting light curves are analysed to determine the luminosity function of SLSNe-I, and their evolutionary time-scales. The DES SLSN-I sample significantly broadens the distribution of SLSN-I light-curve properties when combined with existing samples from the literature. We fit a magnetar model to our SLSNe, and find that this model alone is unable to replicate the behaviour of many of the bolometric light curves. We search the DES SLSN-I light curves for the presence of initial peaks prior to the main light-curve peak. Using a shock breakout model, our Monte Carlo search finds that 3 of our 14 events with pre-max data display such initial peaks. However, 10 events show no evidence for such peaks, in some cases down to an absolute magnitude of <−16, suggesting that such features are not ubiquitous to all SLSN-I events. We also identify a red pre-peak feature within the light curve of one SLSN, which is comparable to that observed within SN2018bsz.

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Supernova host galaxies in the dark energy survey: I. Deep coadds, photometry, and stellar masses

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1302 ◽

2020 ◽

Vol 495 (4) ◽

pp. 4040-4060 ◽

Cited By ~ 2

Author(s):

P Wiseman ◽

M Smith ◽

M Childress ◽

L Kelsey ◽

A Möller ◽

...

Keyword(s):

Dark Energy ◽

High Redshift ◽

High Mass ◽

Host Galaxy ◽

Formation Mechanisms ◽

Atmospheric Conditions ◽

Host Galaxies ◽

Dark Energy Survey ◽

Stellar Masses ◽

Energy Survey

ABSTRACT The 5-yr Dark Energy Survey Supernova Programme (DES-SN) is one of the largest and deepest transient surveys to date in terms of volume and number of supernovae. Identifying and characterizing the host galaxies of transients plays a key role in their classification, the study of their formation mechanisms, and the cosmological analyses. To derive accurate host galaxy properties, we create depth-optimized coadds using single-epoch DES-SN images that are selected based on sky and atmospheric conditions. For each of the five DES-SN seasons, a separate coadd is made from the other four seasons such that each SN has a corresponding deep coadd with no contaminating SN emission. The coadds reach limiting magnitudes of order ∼27 in g band, and have a much smaller magnitude uncertainty than the previous DES-SN host templates, particularly for faint objects. We present the resulting multiband photometry of host galaxies for samples of spectroscopically confirmed type Ia (SNe Ia), core-collapse (CCSNe), and superluminous (SLSNe) as well as rapidly evolving transients (RETs) discovered by DES-SN. We derive host galaxy stellar masses and probabilistically compare stellar-mass distributions to samples from other surveys. We find that the DES spectroscopically confirmed sample of SNe Ia selects preferentially fewer high-mass hosts at high-redshift compared to other surveys, while at low redshift the distributions are consistent. DES CCSNe and SLSNe hosts are similar to other samples, while RET hosts are unlike the hosts of any other transients, although these differences have not been disentangled from selection effects.

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