61. High redshift supernova rates measured with a gravitational telescopeTanja Petrushevska, 2015, published scientific conference contribution abstract Abstract: Supernovae (SNe) are one the most energetic phenomena in the Universe and have been extensively used for astrophysical and cosmological applications. For example, type Ia SNe as distance indicators tools have revealed the accelerating expansion of the universe, while core-collapse (CC) being directly related to the death of massive stars, they trace the star formation history. One of the challenges of SN research is the measurements of the SN rates, particularly at high-z where not many measurements exist. Possible approach to this problem is to use the magnification power of gravitational telescopes such as galaxy clusters. I will present our ground based near-infrared/optical search for gravitationally magnified supernovae behind the galaxy cluster A1689. Our search resulted in the discovery of five highly magnified candidates at high-z classified as CC SNe. We measure the first volumetric CC SN rates. Keywords: supernova rates, gravitational telescopes, galaxy clusters Published in RUNG: 26.01.2018; Views: 3387; Downloads: 0 This document has many files! More... |
62. |
63. |
64. |
65. High-redshift supernova rates measured with the gravitational telescope A1689Tanja Petrushevska, 2016, published scientific conference contribution abstract Abstract: Aims. We present a ground-based, near-infrared search for lensed supernovae behind the massive cluster Abell 1689 at z = 0.18, which is one of the most powerful gravitational telescopes that nature provides.
Methods. Our survey was based on multi-epoch J-band observations with the HAWK-I instrument on VLT, with supporting optical data from the Nordic Optical Telescope.
Results. Our search resulted in the discovery of five photometrically classified, core-collapse supernovae with high redshifts of
0.671 < z < 1.703 and magnifications in the range ∆m = −0.31 to −1.58 mag, as calculated from lensing models in the literature.
Owing to the power of the lensing cluster, the survey had the sensitivity to detect supernovae up to very high redshifts, z ∼ 3,
albeit for a limited region of space. We present a study of the core-collapse supernova rates for 0.4 ≤ z < 2.9, and find good
agreement with previous estimates and predictions from star formation history. During our survey, we also discovered two Type Ia
supernovae in A 1689 cluster members, which allowed us to determine the cluster Ia rate to be 0.14+0.19 ± 0.01 SNuB h2 (SNuB ≡ −0.09
10−12 SNe L−1 yr−1 ), where the error bars indicate 1σ confidence intervals, statistical and systematic, respectively. The cluster rate ⊙,B
normalized by the stellar mass is 0.10+0.13 ± 0.02 in SNuM h2 (SNuM ≡ 10−12 SNe M−1 yr−1). Furthermore, we explore the optimal −0.06 ⊙
future survey for improving the core-collapse supernova rate measurements at z 2 using gravitational telescopes, and for detections with multiply lensed images, and we find that the planned WFIRST space mission has excellent prospects.
Conclusions. Massive clusters can be used as gravitational telescopes to significantly expand the survey range of supernova searches, with important implications for the study of the high-z transient Universe. Keywords: supernova, gravitational telescope, galaxy clusters, Abell 1689, strong lensing Published in RUNG: 26.01.2018; Views: 3439; Downloads: 0 This document has many files! More... |
66. |
67. |
68. |
69. |
70. |