scholarly journals The host galaxies of 106 rapidly evolving transients discovered by the Dark Energy Survey

2020 ◽  
Vol 498 (2) ◽  
pp. 2575-2593 ◽  
Author(s):  
P Wiseman ◽  
M Pursiainen ◽  
M Childress ◽  
E Swann ◽  
M Smith ◽  
...  
Keyword(s):  
Dark Energy ◽  
Gamma Ray ◽  
Fast Time ◽  
Host Galaxies ◽  
Star Forming ◽  
Chemical Enrichment ◽  
Dark Energy Survey ◽  
Explosion Emission ◽  
Stellar Masses ◽  
Energy Survey

ABSTRACT Rapidly evolving transients (RETs), also termed fast blue optical transients, are a recently discovered group of astrophysical events that display rapid luminosity evolution. RETs typically rise to peak in less than 10 d and fade within 30, a time-scale unlikely to be compatible with the decay of Nickel-56 that drives conventional supernovae (SNe). Their peak luminosity spans a range of −15 < Mg < −22.5, with some events observed at redshifts greater than 1. Their evolution on fast time-scales has hindered high-quality follow-up observations, and thus their origin and explosion/emission mechanism remains unexplained. In this paper, we present the largest sample of RETs to date, comprising 106 objects discovered by the Dark Energy Survey, and perform the most comprehensive analysis of RET host galaxies. Using deep-stacked photometry and emission lines from OzDES spectroscopy, we derive stellar masses and star formation rates (SFRs) for 49 host galaxies, and metallicities ([O/H]) for 37. We find that RETs explode exclusively in star-forming galaxies and are thus likely associated with massive stars. Comparing RET hosts to samples of host galaxies of other explosive transients as well as field galaxies, we find that RETs prefer galaxies with high specific SFRs (〈log (sSFR)〉 ∼ −9.6), indicating a link to young stellar populations, similar to stripped-envelope SNe. RET hosts appear to show a lack of chemical enrichment, their metallicities akin to long-duration gamma-ray bursts and superluminous SN host galaxies (〈12 + log (O/H)〉 ∼ 9.4). There are no clear relationships between mass or SFR of the host galaxies and the peak magnitudes or decline rates of the transients themselves.

scholarly journals DESAlert: Enabling Real-Time Transient Follow-Up with Dark Energy Survey Data

2016 ◽  
Vol 33 ◽  
Author(s):  
A. Poci ◽  
K. Kuehn ◽  
T. Abbott ◽  
F. B. Abdalla ◽  
S. Allam ◽  
...  
Keyword(s):  
Dark Energy ◽  
Real Time ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Host Galaxies ◽  
Gamma Ray Burst ◽  
Dark Energy Survey ◽  
Data Products ◽  
Energy Survey

AbstractThe Dark Energy Survey is undertaking an observational programme imaging 1/4 of the southern hemisphere sky with unprecedented photometric accuracy. In the process of observing millions of faint stars and galaxies to constrain the parameters of the dark energy equation of state, the Dark Energy Survey will obtain pre-discovery images of the regions surrounding an estimated 100 gamma-ray bursts over 5 yr. Once gamma-ray bursts are detected by, e.g., the Swift satellite, the DES data will be extremely useful for follow-up observations by the transient astronomy community. We describe a recently-commissioned suite of software that listens continuously for automated notices of gamma-ray burst activity, collates information from archival DES data, and disseminates relevant data products back to the community in near-real-time. Of particular importance are the opportunities that non-public DES data provide for relative photometry of the optical counterparts of gamma-ray bursts, as well as for identifying key characteristics (e.g., photometric redshifts) of potential gamma-ray burst host galaxies. We provide the functional details of the DESAlert software, and its data products, and we show sample results from the application of DESAlert to numerous previously detected gamma-ray bursts, including the possible identification of several heretofore unknown gamma-ray burst hosts.

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

2020 ◽  
Vol 495 (4) ◽  
pp. 4040-4060 ◽  
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.

scholarly journals The WiggleZ Dark Energy Survey: high-resolution kinematics of luminous star-forming galaxies

2011 ◽  
Vol 417 (4) ◽  
pp. 2601-2623 ◽  
Author(s):  
Emily Wisnioski ◽  
Karl Glazebrook ◽  
Chris Blake ◽  
Ted Wyder ◽  
Chris Martin ◽  
...  
Keyword(s):  
Dark Energy ◽  
High Resolution ◽  
Star Forming ◽  
Dark Energy Survey ◽  
Energy Survey

scholarly journals Search for gamma-ray emission from eight dwarf spheroidal galaxy candidates discovered in year two of Dark Energy Survey with Fermi-LAT data

2016 ◽  
Vol 93 (4) ◽  
Author(s):  
Shang Li ◽  
Yun-Feng Liang ◽  
Kai-Kai Duan ◽  
Zhao-Qiang Shen ◽  
Xiaoyuan Huang ◽  
...  
Keyword(s):  
Dark Energy ◽  
Gamma Ray ◽  
Dark Energy Survey ◽  
Gamma Ray Emission ◽  
Energy Survey

scholarly journals GRB host galaxies: theoretical investigation

2011 ◽  
Vol 7 (S279) ◽  
pp. 353-354
Author(s):  
Jirong Mao
Keyword(s):  
Dark Matter ◽  
Star Formation ◽  
Galaxy Evolution ◽  
Gamma Ray ◽  
Dark Matter Halo ◽  
Host Galaxy ◽  
Host Galaxies ◽  
X Ray ◽  
Star Forming ◽  
Stellar Masses

AbstractLong gamma-ray bursts (GRBs) can be linked to the massive stars and their host galaxies are assumed to be the star-forming galaxies within small dark matter halos. We apply a galaxy evolution model, in which the star formation process inside the virialized dark matter halo at a given redshift is achieved. The star formation rates (SFRs) in the GRB host galaxies at different redshifts can be derived from our model. The related stellar masses, luminosities, and metalicities of these GRB host galaxies are estimated. We also calculate the X-ray and optical absorption of GRB afterglow emission. At higher redshift, the SFR of host galaxy is stronger, and the absorption in the X-ray and optical bands of GRB afterglow is stronger, when the dust and metal components are locally released, surrounding the GRB environment. These model predictions are compared with some observational data as well.

scholarly journals Stellar mass as a galaxy cluster mass proxy: application to the Dark Energy Survey redMaPPer clusters

2020 ◽  
Vol 493 (4) ◽  
pp. 4591-4606 ◽  
Author(s):  
A Palmese ◽  
J Annis ◽  
J Burgad ◽  
A Farahi ◽  
M Soares-Santos ◽  
...  
Keyword(s):  
Dark Energy ◽  
Bayesian Model Averaging ◽  
Galaxy Cluster ◽  
Wide Field ◽  
X Ray ◽  
Mass Scaling ◽  
Cluster Mass ◽  
Dark Energy Survey ◽  
Stellar Masses ◽  
Energy Survey

Abstract We introduce a galaxy cluster mass observable, μ⋆, based on the stellar masses of cluster members, and we present results for the Dark Energy Survey (DES) Year 1 (Y1) observations. Stellar masses are computed using a Bayesian model averaging method, and are validated for DES data using simulations and COSMOS data. We show that μ⋆ works as a promising mass proxy by comparing our predictions to X-ray measurements. We measure the X-ray temperature–μ⋆ relation for a total of 129 clusters matched between the wide-field DES Y1 redMaPPer catalogue and Chandra and XMM archival observations, spanning the redshift range 0.1 < $z$ < 0.7. For a scaling relation that is linear in logarithmic space, we find a slope of α = 0.488 ± 0.043 and a scatter in the X-ray temperature at fixed μ⋆ of $\sigma _{{\rm ln} T_\mathrm{ X}|\mu _\star }= 0.266^{+0.019}_{-0.020}$ for the joint sample. By using the halo mass scaling relations of the X-ray temperature from the Weighing the Giants program, we further derive the μ⋆-conditioned scatter in mass, finding $\sigma _{{\rm ln} M|\mu _\star }= 0.26^{+ 0.15}_{- 0.10}$. These results are competitive with well-established cluster mass proxies used for cosmological analyses, showing that μ⋆ can be used as a reliable and physically motivated mass proxy to derive cosmological constraints.

scholarly journals UV-luminous, star-forming hosts of z ∼ 2 reddened quasars in the Dark Energy Survey

2018 ◽  
Vol 475 (3) ◽  
pp. 3682-3699 ◽  
Author(s):  
C F Wethers ◽  
M Banerji ◽  
P C Hewett ◽  
C A Lemon ◽  
R G McMahon ◽  
...  
Keyword(s):  
Dark Energy ◽  
Star Forming ◽  
Dark Energy Survey ◽  
Energy Survey

scholarly journals The Effect of Environment on Type Ia Supernovae in the Dark Energy Survey Three-Year Cosmological Sample

2020 ◽  
Author(s):  
L Kelsey ◽  
M Sullivan ◽  
M Smith ◽  
P Wiseman ◽  
D Brout ◽  
...  
Keyword(s):  
Dark Energy ◽  
Stellar Mass ◽  
Host Galaxy ◽  
Type Ia Supernovae ◽  
Sample Median ◽  
Star Forming ◽  
Dark Energy Survey ◽  
Type Ia ◽  
Ia Supernovae ◽  
Energy Survey

Abstract Analyses of type Ia supernovae (SNe Ia) have found puzzling correlations between their standardised luminosities and host galaxy properties: SNe Ia in high-mass, passive hosts appear brighter than those in lower-mass, star-forming hosts. We examine the host galaxies of SNe Ia in the Dark Energy Survey three-year spectroscopically-confirmed cosmological sample, obtaining photometry in a series of ‘local’ apertures centred on the SN, and for the global host galaxy. We study the differences in these host galaxy properties, such as stellar mass and rest-frame U − R colours, and their correlations with SN Ia parameters including Hubble residuals. We find all Hubble residual steps to be >3σ in significance, both for splitting at the traditional environmental property sample median and for the step of maximum significance. For stellar mass, we find a maximal local step of 0.098 ± 0.018 mag; ∼0.03 mag greater than the largest global stellar mass step in our sample (0.070 ± 0.017 mag). When splitting at the sample median, differences between local and global U − R steps are small, both ∼0.08 mag, but are more significant than the global stellar mass step (0.057 ± 0.017 mag). We split the data into sub-samples based on SN Ia light curve parameters: stretch (x1) and colour (c), finding that redder objects (c > 0) have larger Hubble residual steps, for both stellar mass and U − R, for both local and global measurements, of ∼0.14 mag. Additionally, the bluer (star-forming) local environments host a more homogeneous SN Ia sample, with local U − R r.m.s. scatter as low as 0.084 ± 0.017 mag for blue (c < 0) SNe Ia in locally blue U − R environments.

scholarly journals The STRong lensing Insights into the Dark Energy Survey (STRIDES) 2017/2018 follow-up campaign: discovery of 10 lensed quasars and 10 quasar pairs

2020 ◽  
Vol 494 (3) ◽  
pp. 3491-3511 ◽  
Author(s):  
C Lemon ◽  
M W Auger ◽  
R McMahon ◽  
T Anguita ◽  
Y Apostolovski ◽  
...  
Keyword(s):  
Dark Energy ◽  
Near Infrared ◽  
Infrared Camera ◽  
Variable Component ◽  
Star Forming ◽  
Dark Energy Survey ◽  
Faint Object ◽  
Strong Lensing ◽  
Energy Survey

ABSTRACT We report the results of the STRong lensing Insights into the Dark Energy Survey (STRIDES) follow-up campaign of the late 2017/early 2018 season. We obtained spectra of 65 lensed quasar candidates with ESO Faint Object Spectrograph and Camera 2 on the NTT and Echellette Spectrograph and Imager on Keck, confirming 10 new lensed quasars and 10 quasar pairs. Eight lensed quasars are doubly imaged with source redshifts between 0.99 and 2.90, one is triply imaged (DESJ0345−2545, z = 1.68), and one is quadruply imaged (quad: DESJ0053−2012, z = 3.8). Singular isothermal ellipsoid models for the doubles, based on high-resolution imaging from SAMI on Southern Astrophysical Research Telescope or Near InfraRed Camera 2 on Keck, give total magnifications between 3.2 and 5.6, and Einstein radii between 0.49 and 1.97 arcsec. After spectroscopic follow-up, we extract multi-epoch grizY photometry of confirmed lensed quasars and contaminant quasar + star pairs from DES data using parametric multiband modelling, and compare variability in each system’s components. By measuring the reduced χ2 associated with fitting all epochs to the same magnitude, we find a simple cut on the less variable component that retains all confirmed lensed quasars, while removing 94 per cent of contaminant systems. Based on our spectroscopic follow-up, this variability information improves selection of lensed quasars and quasar pairs from 34-45 per cent to 51–70 per cent, with most remaining contaminants being star-forming galaxies. Using mock lensed quasar light curves we demonstrate that selection based only on variability will over-represent the quad fraction by 10 per cent over a complete DES magnitude-limited sample, explained by the magnification bias and hence lower luminosity/more variable sources in quads.

scholarly journals μ⋆ masses: weak-lensing calibration of the Dark Energy Survey Year 1 redMaPPer clusters using stellar masses

2020 ◽  
Vol 498 (4) ◽  
pp. 5450-5467
Author(s):  
M E S Pereira ◽  
A Palmese ◽  
T N Varga ◽  
T McClintock ◽  
M Soares-Santos ◽  
...  
Keyword(s):  
Dark Energy ◽  
Weak Lensing ◽  
Cluster Member ◽  
Scaling Relation ◽  
Photometric Redshift ◽  
Dark Energy Survey ◽  
Source Sample ◽  
Stellar Masses ◽  
First Time ◽  
Energy Survey

ABSTRACT We present the weak-lensing mass calibration of the stellar-mass-based μ⋆ mass proxy for redMaPPer galaxy clusters in the Dark Energy Survey Year 1. For the first time, we are able to perform a calibration of μ⋆ at high redshifts, z > 0.33. In a blinded analysis, we use ∼6000 clusters split into 12 subsets spanning the ranges 0.1 ≤ z < 0.65 and μ⋆ up to ${\sim} 5.5 \times 10^{13} \, \mathrm{M}_{\odot }$, and infer the average masses of these subsets through modelling of their stacked weak-lensing signal. In our model, we account for the following sources of systematic uncertainty: shear measurement and photometric redshift errors, miscentring, cluster-member contamination of the source sample, deviations from the Navarro–Frenk–White halo profile, halo triaxiality, and projection effects. We use the inferred masses to estimate the joint mass–μ⋆–z scaling relation given by $\langle M_{200c} | \mu _{\star },z \rangle = M_0 (\mu _{\star }/5.16\times 10^{12} \, \mathrm{M_{\odot }})^{F_{\mu _{\star }}} ((1+z)/1.35)^{G_z}$. We find $M_0= (1.14 \pm 0.07) \times 10^{14} \, \mathrm{M_{\odot }}$ with $F_{\mu _{\star }}= 0.76 \pm 0.06$ and Gz = −1.14 ± 0.37. We discuss the use of μ⋆ as a complementary mass proxy to the well-studied richness λ for: (i) exploring the regimes of low z, λ < 20 and high λ, z ∼ 1; and (ii) testing systematics such as projection effects for applications in cluster cosmology.

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