The Dark Energy Survey Supernova Program: Modelling selection efficiency and observed core collapse supernova contamination
M. Vincenzi, M. Sullivan, O. Graur, D. Brout, T. M. Davis, C. Frohmaier, L. Galbany, C. P. Gutiérrez, S. R. Hinton, R. Hounsell, L. Kelsey, R. Kessler, E. Kovac… 展开作者
M. Vincenzi, M. Sullivan, O. Graur, D. Brout, T. M. Davis, C. Frohmaier, L. Galbany, C. P. Gutiérrez, S. R. Hinton, R. Hounsell, L. Kelsey, R. Kessler, E. Kovacs, S. Kuhlmann, J. Lasker, C. Lidman, A. Möller, R. C. Nichol, M. Sako, D. Scolnic, M. Smith, E. Swann, P. Wiseman, J. Asorey, G. F. Lewis, R. Sharp, B. E. Tucker, M. Aguena, S. Allam, S. Avila, E. Bertin, D. Brooks, D. L. Burke, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, F. J. Castander, A. Choi, M. Costanzi, L. N. da Costa, M. E. S. Pereira, J. De Vicente, S. Desai, H. T. Diehl, P. Doel, S. Everett, I. Ferrero, P. Fosalba, J. Frieman, J. García-Bellido, E. Gaztanaga, D. W. Gerdes, D. Gruen, R. A. Gruendl, G. Gutierrez, D. L. Hollowood, K. Honscheid, B. Hoyle, D. J. James, K. Kuehn, N. Kuropatkin, M. A. G. Maia, P. Martini, F. Menanteau, R. Miquel, R. Morgan, A. Palmese, F. Paz-Chinchón, A. A. Plazas, A. K. Romer, E. Sanchez, V. Scarpine, S. Serrano, I. Sevilla-Noarbe, M. Soares-Santos, E. Suchyta, G. Tarle, D. Thomas, C. To, T. N. Varga, A. R. Walker, R. D. Wilkinson
The analysis of current and future cosmological surveys of type Ia supernovae (SNe Ia) at high-redshift depends on the accurate photometric classification of the SN events detected. Generating realistic simulations of photometric SN surveys constitutes an essential step for training and testing photometric classification algorithms, and for correcting biases introduced by selection effects and contamination arising from core collapse SNe in the photometric SN Ia samples. We use published SN time-series spectrophotometric templates, rates, luminosity functions and empirical relationships between SNe and their host galaxies to construct a framework for simulating photometric SN surveys. We present this framework in the context of the Dark Energy Survey (DES) 5-year photometric SN sample, comparing our simulations of DES with the observed DES transient populations. We demonstrate excellent agreement in many distributions, including Hubble residuals, between our simulations and data. We estimate the core collapse fraction expected in the DES SN sample after selection requirements are applied and before photometric classification. After testing different modelling choices and astrophysical assumptions underlying our simulation, we find that the predicted contamination varies from 5.8 to 9.3 per cent, with an average of 7.0 per cent and r.m.s. of 1.1 per cent. Our simulations are the first to reproduce the observed photometric SN and host galaxy properties in high-redshift surveys without fine-tuning the input parameters. The simulation methods presented here will be a critical component of the cosmology analysis of the DES photometric SN Ia sample: correcting for biases arising from contamination, and evaluating the associated systematic uncertainty.
Measuring the Properties of Dark Energy with Photometrically Classified Pan-STARRS Supernovae. I. Systematic Uncertainty from Core-Collapse Supernova Contamination
Cosmological analyses of samples of photometrically-identified Type Ia supernovae (SNe Ia) depend on understanding the effects of 'contamination' from core-collapse and peculiar SN Ia events. We employ a rigorous analysis on state-of-the-art simulations of photometrically identified SN Ia samples and determine cosmological biases due to such 'non-Ia' contamination in the Dark Energy Survey (DES) 5-year SN sample. As part of the analysis, we test on our DES simulations the performance of SuperNNova, a photometric SN classifier based on recurrent neural networks. Depending on the choice of non-I…
The case of SN Ia Hubble diagrams from photometrically selected samples using photometric SN host galaxy redshifts is investigated. The host redshift uncertainties and the contamination by core collapse SNe are addressed. As a test, we use the 3-year photometric SN Ia sample of the SuperNova Legacy Survey (SNLS), made of 437 objects between 0.1 and 1.05 in redshift. We combine this sample with non-SNLS objects of the JLA spectroscopic sample, made of 501 objects mostly below 0.4 in redshift. We study two options for the origin of the redshifts of the photometric sample, either provided entirel…
Multi-Epoch Very Long Baseline Interferometric Observations of the Nuclear Starburst Region of NGC 253: Improved modelling of the supernova and star-formation rates
We use 1169 Pan-STARRS supernovae (SNe) and 195 low-$z$ ($z < 0.1$) SNe Ia to measure cosmological parameters. Though most Pan-STARRS SNe lack spectroscopic classifications, in a previous paper (I) we demonstrated that photometrically classified SNe can be used to infer unbiased cosmological parameters by using a Bayesian methodology that marginalizes over core-collapse (CC) SN contamination. Our sample contains nearly twice as many SNe as the largest previous SN Ia compilation. Combining SNe with Cosmic Microwave Background (CMB) constraints from Planck, we measure the dark energy equation of…
In 2016, the first strongly lensed Type Ia supernova, iPTF16geu at redshift $z=0.409$ with four resolved images arranged symmetrically around the lens galaxy at $z=0.2163$, was discovered. Here, refined observations of iPTF16geu, including the time delay between images, are used to decrease uncertainties in the lens model, including the the slope of the projected surface density of the lens galaxy, $Σ\propto r^{1-η}$, and to constrain the universal expansion rate $H_0$. Imaging with HST provides an upper limit on the slope $η$, in slight tension with the steeper density profiles indicated by i…
The presence of mass inhomogeneities along the line of sight of propagation of light fromdistant objects can induce deflection in the flight path of the photon. This phenomenon is called as gravitational lensing. Lensing can have both distortion (shear) and isotropic magnification effects on the source. We studied the effect of lensing magnification on supernova (SN) Ia in this thesis. Presence of lensing would introduce a source of contamination to the brightness distribution of the source (SN Ia in our case). Thus it also enables one to compute the lensing effect indirectly from the Hubble d…
In this study, we present a modelling of the X-ray emission from the simulated SMBHs within the cosmological hydrodynamical Magneticum Pathfinder Simulation, in order to study the statistical properties of the resulting X-ray Active Galactic Nuclei (AGN) population and their expected contribution to the X-ray flux from galaxy clusters. The simulations reproduce the evolution of the observed unabsorbed AGN bolometric luminosity functions (LFs) up to redshift z~2, consistently with previous works. Furthermore, we study the evolution of the LFs in the soft (SXR) and hard (HXR) X-ray bands by mean…
Characterising the Standardisation Properties of Type Ia Supernovae in the z band with Hierarchical Bayesian Modelling
University of Cambridge（剑桥大学）；University of Birmingham（伯明翰大学）；University of Hawai’i（夏威夷大学）；University of California, Santa Cruz（加利福尼亚大学圣克鲁兹分校）；Stockholm University（斯德哥尔摩大学）
Follow-up of SN 2025wny V: Lens Modelling and Cosmography of a Strongly Lensed Superluminous Supernova at $z = 2.015$ using Space Data
Stockholm University（斯德哥尔摩大学）；University of Birmingham（伯明翰大学）；University of California, Berkeley（加州大学伯克利分校）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；University of Portsmouth（朴茨茅斯大学）；University of Cambridge（剑桥大学）
Modeling the probability distribution for cosmological analysis with photometrically classified samples
Observatório do Valongo, Universidade Federal do Rio de Janeiro（瓦隆戈天文台，里约热内卢联邦大学）；Instituto de Física, Universidade Federal do Rio de Janeiro（物理研究所，里约热内卢联邦大学）
BayeSN $\times$ Dovekie: Joint Photometric Cross-calibration and SED Modelling of Type Ia Supernovae
Institute of Astronomy and Kavli Institute for Cosmology, University of Cambridge（剑桥大学天体物理研究所与卡弗里宇宙学研究所）；School of Physics and Astronomy, University of Southampton（南安普顿大学物理与天文学院）
Non-LTE time-dependent spectroscopic modelling of type II-plateau supernovae from the photospheric to the nebular phase: case study for 15 and 25Msun progenitor stars
