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1.
LensWatch. II. improved photometry and time-delay constraints on the strongly lensed type Ia supernova 2022qmx ("SN Zwicky") with Hubble Space Telescope template observations
C. Larison, Justin Pierel, M. J. B. Newman, S. W. Jha, D. Gilman, E. E. Hayes, A. Agrawal, N. Arendse, Mateusz Bronikowski, Tanja Petrushevska, 2025, original scientific article

Abstract: Abstract Strongly lensed supernovae (SNe) are a rare class of transient that can offer tight cosmological constraints that are complementary to methods from other astronomical events. We present a follow-up study of one recently discovered strongly lensed SN, the quadruply imaged type Ia SN 2022qmx (aka “SN Zwicky”), at z = 0.3544. We measure updated, template-subtracted photometry for SN Zwicky and derive improved time delays and magnifications. This is possible because SNe are transient, fading away after reaching their peak brightness. Specifically, we measure point-spread-function photometry for all four images of SN Zwicky in three Hubble Space Telescope WFC3/UVIS passbands (F475W, F625W, and F814W) and one WFC3/IR passband (F160W), with template images taken ∼11 months after the epoch in which the SN images appear. We find consistency to within 2σ between lens-model-predicted time delays (≲1 day) and measured time delays with HST colors (≲2 days), including the uncertainty from chromatic microlensing that may arise from stars in the lensing galaxy. The standardizable nature of SNe Ia allows us to estimate absolute magnifications for the four images, with images A and C being elevated in magnification compared to lens model predictions by about 6σ and 3σ, respectively, confirming previous work. We show that millilensing or differential dust extinction is unable to explain these discrepancies, and we find evidence for the existence of microlensing in images A, C, and potentially D that may contribute to the anomalous magnification.
Keywords: supernova, strong lensing, astronomy
Published in RUNG: 10.03.2025; Views: 336; Downloads: 9
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2.
Strongly lensed supernovae, the past and the future : lecture at the University of Cambridge, 26. 6. 2024
Tanja Petrushevska, 2024, invited lecture at foreign university

Abstract: The searches and observations of supernovae (SNe) have been motivated by the fact that they are exceptionally useful for various astrophysical and cosmological applications. Most prominently, Type Ia SNe (SNe Ia) have been used as distance indicators showing that the expansion rate of the Universe is accelerating. The strong gravitational lensing effect provides another powerful tool and occurs when a foreground mass distribution is located along the line of sight to a background source. It can happen so that galaxies and galaxy clusters can act as “gravitational telescopes”, boosting the faint signals from distant SNe and galaxies. Thanks to the magnification boost provided by the gravitational telescope, we are able to probe galaxies and SNe that otherwise would be undetectable. Therefore, the combination of the two tools, SNe and strong lensing, in the single phenomenon of strongly lensed SNe, provides a powerful simultaneous probe of several cosmological and astrophysical phenomena. By measuring the time delays of strongly lensed supernovae and having a high-quality strong lensing model of the galaxy cluster, it is possible to measure the Hubble constant with competitive precision. In this talk, I will present some of the past and recent results that have been possible due to the observations of strongly lensed supernovae and anticipate what we can expect in the future from the upcoming telescope surveys, such as the Vera C. Rubin Observatory and Nancy G. Roman Space Telescope.
Keywords: supernova, strong lensing, Hubble constant
Published in RUNG: 26.06.2024; Views: 1123; Downloads: 14
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3.
Strongly lensed supernovae : the past and the future
Tanja Petrushevska, 2024, invited lecture at foreign university

Keywords: invited seminar, supernova, strong lensing, James Webb space telescope
Published in RUNG: 11.06.2024; Views: 1089; Downloads: 6
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What can we do with strongly lensed supernovae?
Tanja Petrushevska, 2023, published scientific conference contribution abstract

Keywords: cosmology, strong lensing, supernovae
Published in RUNG: 07.09.2023; Views: 2062; Downloads: 5
.pdf Full text (18,56 MB)

7.
Contributed talk at the international conference "Cosmology in Miramare" 2023
Tanja Petrushevska, 2023, published scientific conference contribution abstract

Abstract: The searches and observations of supernovae (SNe) have been motivated by the fact that they are exceptionally useful for various astrophysical and cosmological applications. Most prominently, Type Ia SNe (SNe Ia) have been used as distance indicators showing that the expansion rate of the Universe is accelerating. The strong gravitational lensing effect provides another powerful tool and occurs when a foreground mass distribution is located along the line of sight to a background source. It can happen so that galaxies and galaxy clusters can act as “gravitational telescopes”, boosting the faint signals from distant SNe and galaxies. Thanks to the magnification boost provided by the gravitational telescope, we are able to probe galaxies and SNe that otherwise would be undetectable. Therefore, the combination of the two tools, SNe and strong lensing, in the single phenomenon of strongly lensed SNe, provides a powerful simultaneous probe of several cosmological and astrophysical phenomena. By measuring the time delays of strongly lensed supernovae and having a high-quality strong lensing model of the galaxy cluster, it is possible to measure the Hubble constant with competitive precision. In this talk, I will present some of the past and recent results that have been possible due to the observations of strongly lensed supernovae and anticipate what we can expect in the future from the upcoming telescope surveys, such as the Vera C. Rubin Observatory and Nancy G. Roman Space Telescope.
Keywords: cosmology, supernovae, strong lensing
Published in RUNG: 07.09.2023; Views: 2171; Downloads: 4
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8.
Strong lensing as a tool to study the early universe : written report
Brankica Apostolova, 2023, research project (high school)

Keywords: strong lensing, astrophysics, Roman Space Telescope, galaxy clustersv, galaxies
Published in RUNG: 23.08.2023; Views: 1916; Downloads: 0
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10.
Strongly lensed supernovae at high-redshifts : Invited seminar 'Strongly lensed supernovae at high-redshifts' at NCBJ, Poland
Tanja Petrushevska, invited lecture at foreign university

Abstract: The searches and observations of supernovae (SNe) have been motivated by the fact that they are exceptionally useful for various astrophysical and cosmological applications. Most prominently, Type Ia SNe (SNe Ia) have been used as distance indicators showing that the expansion rate of the Universe is accelerating. The strong gravitational lensing effect provides another powerful tool and occurs when a foreground mass distribution is located along the line of sight to a background source. It can happen so that galaxies and galaxy clusters can act as “gravitational telescopes”, boosting the faint signals from distant SNe and galaxies. Thanks to the magnification boost provided by the gravitational telescope, we are able to probe galaxies and SNe that otherwise would be undetectable. Therefore, the combination of the two tools, SNe and strong lensing, in the single phenomenon of strongly lensed SNe, provides a powerful simultaneous probe of several cosmological and astrophysical phenomena. In this talk, I will present some of the past results that have been possible due to the observations of strongly lensed supernovae and anticipate what we can expect in the future from the upcoming telescope surveys.
Keywords: supernovae, strong lensing
Published in RUNG: 16.03.2023; Views: 2224; Downloads: 0
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