scholarly journals Cosmological Inference from Host-Selected Type Ia Supernova Samples

2017 ◽  
Vol 34 ◽  
Author(s):  
Syed A. Uddin ◽  
Jeremy Mould ◽  
Chris Lidman ◽  
Vanina Ruhlmann-Kleider ◽  
Delphine Hardin
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Real Time ◽  
Matter Density ◽  
Light Curves ◽  
Type Ia Supernova ◽  
Type Ia

AbstractWe compare two Type Ia supernova samples that are drawn from a spectroscopically confirmed Type Ia supernova sample: a host-selected sample in which SNe Ia are restricted to those that have a spectroscopic redshift from the host; and a broader, more traditional sample in which the redshift could come from either the SN or the host. The host-selected sample is representative of SN samples that will use the redshift of the host to infer the SN redshift, long after the SN has faded from view. We find that SNe Ia that are selected on the availability of a redshift from the host differ from SNe Ia that are from the broader sample. The former tend to be redder, have narrower light curves, live in more massive hosts, and tend to be at lower redshifts. We find that constraints on the equation of state of dark energy, w, and the matter density, ΩM, remain consistent between these two types of samples. Our results are important for ongoing and future supernova surveys, which unlike previous supernova surveys, will have limited real-time follow-up to spectroscopically classify the SNe they discover. Most of the redshifts in these surveys will come from the hosts.

scholarly journals THE EFFECT OF DIFFERENT OBSERVATIONAL DATA IN CONSTRAINING COSMOLOGICAL PARAMETERS

2012 ◽  
Vol 10 ◽  
pp. 85-94 ◽  
Author(s):  
YUNGUI GONG ◽  
QING GAO ◽  
ZONG-HONG ZHU
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Observational Data ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Wilkinson Microwave Anisotropy Probe ◽  
Model Parameters ◽  
Type Ia Supernova ◽  
Equation Of State Parameter ◽  
Type Ia

We use the SNLS3 compilation of 472 type Ia supernova data, the baryon acoustic oscillation measurement of distance, and the cosmic microwave background radiation data from the seven year Wilkinson Microwave Anisotropy Probe to study the effect of their different combinations on the fittings of cosmological parameters. Neither BAO nor WMAP7 data alone gives good constraint on the equation of state parameter of dark energy, but both WMAP7 data and BAO data help type Ia supernova data break the degeneracies among the model parameters, hence tighten the constraint on the variation of equation of state parameter wa, and WMAP7 data does the job a little better. Although BAO and WMAP7 data provide reasonably good constraints on Ωm and Ωk, it is not able to constrain the dynamics of dark energy, we need SNe Ia data to probe the property of dark energy, especially the variation of the equation of state parameter of dark energy. For the SNLS SNe Ia data, the nuisance parameters α and β are consistent for all different combinations of the above data. Their impacts on the fittings of cosmological parameters are minimal. ΛCDM model is consistent with current observational data.

CPL effective dark energy from the backreaction effect

2019 ◽  
Vol 34 (21) ◽  
pp. 1950167
Author(s):  
Yan-Hong Yao ◽  
Xin-He Meng
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Perfect Fluid ◽  
Coming Out ◽  
Hubble Parameter ◽  
Small Scale ◽  
Type Ia Supernova ◽  
Type Ia ◽  
The Difference ◽  
The Universe

In this paper, we interpret the dark energy as an effect caused by small-scale inhomogeneities of the universe with the use of the spatial averaged approach of Buchert [Gen. Relat. Gravit. 32, 105 (2000); 33, 1381 (2001)]. The model considered here adopts the Chevallier–Polarski–Linder (CPL) parametrizations of the equation of state of the effective perfect fluid from the backreaction effect. Thanks to the effective geometry introduced by Larena et al. [Phys. Rev. D 79, 083011 (2009)] in their previous work, we confront such backreaction model with the latest type Ia supernova and Hubble parameter observations, coming out with the results that reveal the difference between the Friedmann–Lemaître–Robertson–Walker model and backreaction model.

scholarly journals Optimizing Type Ia supernova follow-up in future dark energy surveys

2008 ◽  
Vol 125 ◽  
pp. 012011
Author(s):  
P Nugent ◽  
R Thomas ◽  
G Aldering
Keyword(s):  
Dark Energy ◽  
Type Ia Supernova ◽  
Type Ia

scholarly journals Inference for the dark energy equation of state using Type IA supernova data

2009 ◽  
Vol 3 (1) ◽  
pp. 144-178 ◽  
Author(s):  
Christopher Genovese ◽  
Peter Freeman ◽  
Larry Wasserman ◽  
Robert Nichol ◽  
Christopher Miller
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Energy Equation ◽  
Type Ia Supernova ◽  
Type Ia

scholarly journals Transient processing and analysis using AMPEL: alert management, photometry, and evaluation of light curves

2019 ◽  
Vol 631 ◽  
pp. A147 ◽  
Author(s):  
J. Nordin ◽  
V. Brinnel ◽  
J. van Santen ◽  
M. Bulla ◽  
U. Feindt ◽  
...  
Keyword(s):  
Real Time ◽  
High Throughput ◽  
Light Curves ◽  
Wide Field ◽  
Field Surveys ◽  
Scientific Analysis ◽  
Type Ia ◽  
Transient Data ◽  
Ia Supernovae

Context. Both multi-messenger astronomy and new high-throughput wide-field surveys require flexible tools for the selection and analysis of astrophysical transients. Aims. Here we introduce the alert management, photometry, and evaluation of light curves (AMPEL) system, an analysis framework designed for high-throughput surveys and suited for streamed data. AMPEL combines the functionality of an alert broker with a generic framework capable of hosting user-contributed code; it encourages provenance and keeps track of the varying information states that a transient displays. The latter concept includes information gathered over time and data policies such as access or calibration levels. Methods. We describe a novel ongoing real-time multi-messenger analysis using AMPEL to combine IceCube neutrino data with the alert streams of the Zwicky Transient Facility (ZTF). We also reprocess the first four months of ZTF public alerts, and compare the yields of more than 200 different transient selection functions to quantify efficiencies for selecting Type Ia supernovae that were reported to the Transient Name Server (TNS). Results. We highlight three channels suitable for (1) the collection of a complete sample of extragalactic transients, (2) immediate follow-up of nearby transients, and (3) follow-up campaigns targeting young, extragalactic transients. We confirm ZTF completeness in that all TNS supernovae positioned on active CCD regions were detected. Conclusions. AMPEL can assist in filtering transients in real time, running alert reaction simulations, the reprocessing of full datasets as well as in the final scientific analysis of transient data. This is made possible by a novel way of capturing transient information through sequences of evolving states, and interfaces that allow new code to be natively applied to a full stream of alerts. This text also introduces a method by which users can design their own channels for inclusion in the AMPEL live instance that parses the ZTF stream and the real-time submission of high-quality extragalactic supernova candidates to the TNS.

Early Blue Excess from the Type Ia Supernova 2017cbv

2017 ◽  
Vol 14 (S339) ◽  
pp. 47-49
Author(s):  
G. Hosseinzadeh
Keyword(s):  
Light Curve ◽  
Standard Type ◽  
Circumstellar Material ◽  
Type Ia Supernova ◽  
Unusual Distribution ◽  
Photometric Observations ◽  
Type Ia ◽  
Optical Light Curve ◽  
Ia Supernovae

AbstractThis paper presented very early, high-cadence photometric observations of the nearby Type Ia SN 2017cbv. The light-curve is unique in that during the first five days of observations it has a blue bump in the U, B, and g bands which is clearly resolved by virtue of our photometric cadence of 5.7 hr during that time span. We modelled the light-curve as the combination of an early shock of the supernova ejecta against a non-degenerate companion star plus a standard Type Ia supernova component. Our best-fit model suggested the presence of a subgiant star 56 R⊙ from the exploding white dwarf, although that number is highly model-dependent. While the model matches the optical light-curve well, it over-predicts the flux expected in the ultraviolet bands. That may indicate that the shock is not a blackbody, perhaps because of line blanketing in the UV. Alternatively, it could point to another physical explanation for the optical blue bump, such as interaction with circumstellar material or an unusual distribution of the element Ni. Early optical spectra of SN 2017cbv show strong carbon absorption as far as day –13 with respect to maximum light, suggesting that the progenitor system contained a significant amount of unburnt material. These results for SN 2017cbv illustrate the power of early discovery and intense follow-up of nearby supernovæ for resolving standing questions about the progenitor systems and explosion mechanisms of Type Ia supernovæ.

scholarly journals RECONSTRUCTION OF 5D COSMOLOGICAL MODELS FROM RECENT OBSERVATIONS

2007 ◽  
Vol 16 (10) ◽  
pp. 1573-1579
Author(s):  
CHENGWU ZHANG ◽  
LIXIN XU ◽  
YONGLI PING ◽  
HONGYA LIU
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Equation Of State ◽  
Cosmological Solution ◽  
Type Ia Supernovae ◽  
Shift Parameter ◽  
Type Ia ◽  
Ia Supernovae ◽  
Best Fit ◽  
The Universe

We use a parameterized equation of state (EOS) of dark energy to a 5D Ricci-flat cosmological solution and suppose the universe contains two major components: dark matter and dark energy. Using the recent observational datasets: the latest 182 type Ia Supernovae Gold data, the three-year WMAP CMB shift parameter and the SDSS baryon acoustic peak, we obtain the best fit values of the EOS and two major components' evolution. We find that the best fit EOS crosses -1 in the near past where z ≃ 0.07, the present best fit value of wx(0) < -1 and for this model, the universe experiences the acceleration at about z ≃ 0.5.

scholarly journals Using gamma ray monitoring to avoid missing the next Milky Way Type Ia supernova

2019 ◽  
Vol 486 (2) ◽  
pp. 2910-2918 ◽  
Author(s):  
Xilu Wang (王夕露) ◽  
Brian D Fields ◽  
Amy Yarleen Lien (連雅琳)
Keyword(s):  
Gamma Rays ◽  
Milky Way ◽  
Gamma Ray ◽  
Galactic Plane ◽  
Early Warning Systems ◽  
Light Curves ◽  
X Rays ◽  
Warning Systems ◽  
Type Ia Supernova ◽  
Type Ia

Abstract A Milky Way Type Ia supernova (SNIa) could be unidentified or even initially unnoticed, being dim in radio, X-rays, and neutrinos, and suffering large optical/IR extinction in the Galactic plane. But SNIa emit nuclear gamma-ray lines from 56Ni → 56Co → 56Fe radioactive decays. These lines fall within the Fermi/GBM energy range, and the 56Ni 158 keV line is detectable by Swift/BAT. Both instruments frequently monitor the Galactic plane, which is transparent to gamma rays. Thus GBM and BAT are ideal Galactic SNIa early warning systems. We simulate SNIa MeV light curves and spectra to show that GBM and BAT could confirm a Galactic SNIa explosion, followed by Swift localization and observation in X-rays and UVOIR band. The time of detection depends sensitively on the 56Ni distribution, and can be as early as a few days if ${\gtrsim } 10{{\ \rm per\ cent}}$ of the 56Ni is present in the surface as suggested by SN2014J gamma data.

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