11. Strongly Lensed Supernovae in Well-Studied Galaxy Clusters with the Vera C. Rubin ObservatoryTanja Petrushevska, 2020, original scientific article Abstract: Strong lensing by galaxy clusters can be used to significantly expand the survey reach, thus allowing observation of magnified high-redshift supernovae that otherwise would remain undetected. Strong lensing can also provide multiple images of the galaxies that lie behind the clusters. Detection of strongly lensed Type Ia supernovae (SNe Ia) is especially useful because of their standardizable brightness, as they can be used to improve either cluster lensing models or independent measurements of cosmological parameters. The cosmological parameter, the Hubble constant, is of particular interest given the discrepancy regarding its value from measurements with different approaches. Here, we explore the feasibility of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) of detecting strongly lensed SNe in the field of five galaxy clusters (Abell 1689 and Hubble Frontier Fields clusters) that have well-studied lensing models. Considering the 88 systems composed of 268 individual multiple images in the five cluster fields, we find that the LSST will be sensitive to SNe Ia (SNe IIP) exploding in 41 (23) galaxy images. The range of redshift of these galaxies is between 1.01 < z < 3.05. During its 10 years of operation, LSST is expected to detect 0.2 ± 0.1 SN Ia and 0.9 ± 0.3 core collapse SNe. However, as LSST will observe many more massive galaxy clusters, it is likely that the expectations are higher. We stress the importance of having an additional observing program for photometric and spectroscopic follow-up of the strongly lensed SNe detected by LSST.
Keywords: supernovae, strong gravitational lensing, galaxy clusters
Published in RUNG: 28.11.2020; Views: 3759; Downloads: 98
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12. Prospects for Strongly Lensed Supernovae Behind Hubble FrontierFields Galaxy Clusters with the James Webb Space TelescopeTanja Petrushevska, 2018, original scientific article Abstract: Measuring time delays from strongly lensed supernovae (SNe) is emerging as a novel andindependent tool for estimating the Hubble constant (H0). This is very important given the recent discordin the value of H0) from two methods that probe different distance ranges. The success of this techniquewill rely of our ability to discover strongly lensed SNe with measurable time delays. Here, we present themagnifications and the time delay s for the multiply-imaged galaxies behind the Hubble Frontier Fields(HFF) galaxy clusters, by using recently published lensing models. Continuing on our previous work donefor Abell 1689 (A1689) and Abell 370, we also show the prospects of observing strongly lensed SNe behindthe HFF clusters with the upcoming James Webb Space Telescope (JWST). With four 1-hour visits inone year, the summed expectations of all six HFF clusters are ∼0 .5 core-collapse (CC) SNe and 0.06Type Ia SNe (SNe Ia) in F115W band, while with F150W the expectations are higher, ∼0.9 CC SNeand ∼0.06 SNe Ia. These estimates match those expected by only surveying A1689, proving that theperformance of A1689 as gravitational telescope is superior. In the five HFF clusters presented here, wefind that F150W will be able to detect SNe Ia (SNe IIP) exploding in 93 (80) pairs multiply-imaged galaxieswith time delays of less than 5 years.
Keywords: supernovae, JWST, Hubble constant, strong lensing
Published in RUNG: 03.01.2019; Views: 4266; Downloads: 0
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13. Exploring the Universe with supernovaeTanja Petrushevska, published scientific conference contribution abstract (invited lecture) Abstract: Supernovae have proven to be exquisite tools for a variety of astrophysics and cosmology topics. In this lecture, I will highlight a selection of dedicated tele- scopic surveys for detecting supernovae and I will report some of our interesting discoveries during the past few years. I will dedicate special attention to strongly lensed supernovae by galaxies and galaxy clusters. Under the right circumstances, multiple images of the lensed supernovae can be observed, and due to the variable nature of the objects, the difference between the arrival times of the images can be measured. Since the images have taken different paths through space before reaching us, the time-differences are sensitive to the expansion rate of the universe. Therefore, measuring time delays from strongly lensed supernovae is emerging as a novel and independent tool for estimating the Hubble constant (H0). This is very important given the recent discord in the value of H0 from two methods that probe different distance ranges: the ESA mission Planck value corresponds to 67.74 ± 0.46 km s−1 Mpc−1; [1], while a reanalysis of the local distance scale gives 73.24 ± 1.74 km s−1 Mpc−1; [2, 3], these measurements thus being inconsistent at the ≈ 3.5σ level. Therefore, the results of additional independent and high- precision techniques, which rely on different physics, are of key importance. In this context, I will report our discovery of the first resolved multiply-imaged gra- vitationally lensed supernova Type Ia [4]. Moving forward, I will discuss some of the prospects of upcoming facilities such as the Large Synoptic Survey Telescope and James Webb Space Telescope [5, 6].
Keywords: supernovae, strong lensing, neutron stars
Published in RUNG: 29.11.2018; Views: 4185; Downloads: 0
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15. Prospects for lensed supernovae behind galaxy clusters with the James Webb Space TelescopeTanja Petrushevska, 2018, published scientific conference contribution abstract Abstract: Galaxies, and clusters of galaxies, can act as gravitational lenses and magnify the light of
objects behind them. The effect enables observations of very distant supernovae, that
otherwise would be too faint to be detected by existing telescopes, and allows studies of
the frequency and properties of these rare phenomena when the universe was young.
Under the right circumstances, multiple images of the lensed supernovae can be
observed, and due to the variable nature of the objects, the difference between the arrival
times of the images can be measured. Since the images have taken different paths
through space before reaching us, the time-differences are sensitive to the expansion rate
of the universe. One class of supernovae, Type Ia, are of particular interest to detect. Their
well known brightness can be used to determine the magnification, which can be used to
understand the lensing systems. I will also report our discovery of the first resolved
multiply-imaged gravitationally lensed supernova Type Ia. I will also show the expectations
of search campaigns that can be conducted with future facilities, such as the James Webb
Space Telescope (JWST) or the Wide-Field Infrared Survey Telescope (WFIRST).
Keywords: Strong lensing, Hubble constant, measuring expansion history with time delays, lensed supernovae
Published in RUNG: 09.07.2018; Views: 4939; Downloads: 141
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16. Searching for supernovae in the multiply-imaged galaxies behind the gravitational telescope A370Tanja Petrushevska, Ariel Goobar, D. J. Lagattuta, R. Amanullah, Laura Hangard, S. Fabbro, C. Lindman, K. Paech, J. Richard, J.P. Kneib, 2017, original scientific article Abstract: Aims. Strong lensing by massive galaxy clusters can provide magnification of the flux and even multiple images of the galaxies that lie behind them. This phenomenon facilitates observations of high-redshift supernovae (SNe) that would otherwise remain undetected. Type Ia supernovae (SNe Ia) detections are of particular interest because of their standard brightness, since they can be used to improve either cluster lensing models or cosmological parameter measurements.
Methods. We present a ground-based, near-infrared search for lensed SNe behind the galaxy cluster Abell 370. Our survey was based on 15 epochs of J-band observations with the HAWK-I instrument on the Very Large Telescope (VLT). We use Hubble Space Telescope (HST) photometry to infer the global properties of the multiply-imaged galaxies. Using a recently published lensing model of Abell 370, we also present the predicted magnifications and time delays between the images.
Results. In our survey, we did not discover any live SNe from the 13 lensed galaxies with 47 multiple images behind Abell 370. This is consistent with the expectation of 0.09 ± 0.02 SNe calculated based on the measured star formation rate. We compare the expectations of discovering strongly lensed SNe in our survey and that performed with HST during the Hubble Frontier Fields (HFF) programme. We also show the expectations of search campaigns that can be conducted with future facilities, such as the James Webb Space Telescope (JWST) or the Wide-Field Infrared Survey Telescope (WFIRST). We show that the NIRCam instrument aboard the JWST will be sensitive to most SN multiple images in the strongly lensed galaxies and thus will be able to measure their time delays if observations are scheduled accordingly.
Keywords: gravitational lensing: strong / supernovae: general / galaxies: clusters: individual: A 370
Published in RUNG: 28.06.2018; Views: 4938; Downloads: 180
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17. Supernovae seen through gravitational telescopesTanja Petrushevska, 2018, published scientific conference contribution abstract (invited lecture) Abstract: Galaxies, and clusters of galaxies, can act as gravitational lenses and magnify the light of objects behind them. The effect enables observations of very distant supernovae, that otherwise would be too faint to be detected by existing telescopes, and allows studies of the frequency and properties of these rare phenomena when the universe was young. Under the right circumstances, multiple images of the lensed supernovae can be observed, and due to the variable nature of the objects, the difference between the arrival times of the images can be measured. Since the images have taken different paths through space before reaching us, the time-differences are sensitive to the expansion rate of the universe. One class of supernovae, Type Ia, are of particular interest to detect. Their well known brightness can be used to determine the magnification, which can be used to understand the lensing systems. I will also report our discovery of the first resolved multiply-imaged gravitationally lensed supernova Type Ia.
Keywords: lensed supernovae, strong lensing
Published in RUNG: 03.05.2018; Views: 4504; Downloads: 0
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19. 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: 4704; Downloads: 0
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20. Supernovae seen through gravitational telescopesTanja Petrushevska, 2017, doctoral dissertation Abstract: Gravitational lenses such as galaxies and galaxy clusters, can magnify the flux of background galaxies. These galaxies at high redshift can host supernovae (SNe) which, thanks to the magnification boost due to lensing, can be observed, otherwise too faint to be detected by current telescopes. Under the right circumstances, the background galaxies may also have multiple images due to the strong lensing. Of particular interest is to detect lensed supernovae of type Ia (SNe Ia), because of their standard brightness. They could help improve lensing models and, if multiple images are observed, the Hubble constant can be measured independently.
In this thesis, we use galaxy clusters as gravitational telescopes to search for lensed SNe at high redshift. We performed ground-based, near-infrared and optical search campaigns towards the massive clusters Abell 1689 and 370, which are among the most powerful gravitational telescopes known. Our search resulted in the discovery of five photometrically classified, core- collapse SNe at redshifts of 0.671 < z < 1.703 with significant magnification from the cluster. Owing to the power of the lensing cluster, we calculated the volumetric core-collapse SN rates for 0.4 z < 2.9, and find good agreement with previous estimates and predictions from cosmic star formation history. During our survey, we also discovered two SNe Ia in A1689 cluster members, which allowed us to determine the cluster Ia rate. Furthermore, we discuss the expectations of finding lensed SNe at high redshift in simulated search campaigns that can be conducted with upcoming ground- and space-based telescopes.
Magnification from a galaxy lens also allows for detailed studies of the SN properties at high redshift that otherwise would not be possible. Spec- troscopic observations of lensed high-redshift SNe Ia are of particular interest since they can be used to test for evolution of the standard candle nature of these objects. However, if systematic redshift-dependent properties are found, their utility for future surveys could be challenged. We investigate whether the properties of the strongly lensed and very distant SN Ia PS1- 10afx at z = 1.4, deviates from the well-studied nearby and intermediate populations of normal SNe Ia. In other study, we report the discovery of the first resolved multiply-imaged gravitationally lensed SN Ia.
Keywords: supernovae, gravitational telescopes, galaxy clusters, lensed supernovae, strong lensing, astronomical surveys and telescopes
Published in RUNG: 23.01.2018; Views: 5260; Downloads: 0
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