LensWatch. I. Resolved HST Observations and Constraints on the Strongly Lensed Type Ia Supernova 2022qmx (“SN Zwicky”)

Abstract

Supernovae (SNe) that have been multiply imaged by gravitational lensing are rare and powerful probes for cosmology. Each detection is an opportunity to develop the critical tools and methodologies needed as the sample of lensed SNe increases by orders of magnitude with the upcoming Vera C. Rubin Observatory and Nancy Grace Roman Space Telescope. The latest such discovery is of the quadruply imaged Type Ia SN 2022qmx (aka, “SN Zwicky”) at z = 0.3544. SN Zwicky was discovered by the Zwicky Transient Facility in spatially unresolved data. Here we present follow-up Hubble Space Telescope observations of SN Zwicky, the first from the multicycle “LensWatch (www.lenswatch.org)” program. We measure photometry for each of the four images of SN Zwicky, which are resolved in three WFC3/UVIS filters (F475W, F625W, and F814W) but unresolved with WFC3/IR F160W, and present an analysis of the lensing system using a variety of independent lens modeling methods. We find consistency between lens-model-predicted time delays (≲1 day), and delays estimated with the single epoch of Hubble Space Telescope colors (≲3.5 days), including the uncertainty from chromatic microlensing (∼1–1.5 days). Our lens models converge to an Einstein radius of θ E = ( 0.168 − 0.005 + 0.009 ) ″ , the smallest yet seen in a lensed SN system. The “standard candle” nature of SN Zwicky provides magnification estimates independent of the lens modeling that are brighter than predicted by ∼ 1.7 − 0.6 + 0.8 mag and ∼ 0.9 − 0.6 + 0.8 mag for two of the four images, suggesting significant microlensing and/or additional substructure beyond the flexibility of our image-position mass models.

The JWST Discovery of the Triply Imaged Type Ia “Supernova H0pe” and Observations of the Galaxy Cluster PLCK G165.7+67.0

“…The first spectroscopically confirmed multiply imaged Type Ia SNe (SNe Ia) were "iPTF16geu" at z = 0.409 with an Einstein ring radius θ ≈ 0 3 (Goobar et al 2017) and "SN Zwicky" at z = 0.3554 with θ ≈ 0 18 (Pierel et al 2023;Goobar et al 2023). The time delays for both of these were ∼hours with uncertainties of ∼1-2 days, and therefore, the uncertainties in the distance ratios were large.…”

JWST Photometric Time-delay and Magnification Measurements for the Triply Imaged Type Ia “SN H0pe” at z = 1.78

“…Precise measurements of this "time delay" yield a direct distance measurement to the lens system that constrains the Hubble constant (H 0 ) in a single step (e.g., Refsdal 1964;Paraficz & Hjorth 2009;Linder 2011;Treu & Marshall 2016;Grillo et al 2018Grillo et al , 2020Birrer et al 2022b;Treu et al 2022;Suyu et al 2024). Quasars have historically been used for this purpose (e.g., Vuissoz et al 2008;Tewes et al 2013;Bonvin et al 2017Bonvin et al , 2018Bonvin et al , 2019aBirrer et al 2019;Wong et al 2020), since supernovae (SNe) exploding in multiply imaged galaxies are relatively rare, with only a handful discovered thus far (Kelly et al 2015;Goobar et al 2017Goobar et al , 2023Rodney et al 2021;Chen et al 2022;Kelly et al 2022;Pierel et al 2023). Nevertheless, SNe have several advantages over quasars that are attractive for cosmological measurements: (1) SNe fade, enabling predictive experiments on the delayed appearance of trailing images and more accurate photometry, as the SN (or quasar), lens, and host fluxes are otherwise highly blended (Ding et al 2021); (2) SNe generally have predictable behavior compared to quasars, simplifying time-delay measurements and requiring much shorter observing campaigns; and (3) the impact of a "microlensing time delay" is significantly mitigated owing to the more compact source size (Tie & Kochanek 2018;Bonvin et al 2019b).…”

“…SNe Ia are of particular value when strongly lensed, as their standardizable absolute brightness can provide additional leverage for lens modeling by limiting the uncertainty caused by the mass sheet degeneracy (Falco et al 1985;Kolatt & Bartelmann 1998;Holz 2001;Oguri & Kawano 2003;Nordin et al 2014;Patel et al 2014;Rodney et al 2015;Xu et al 2016;Foxley-Marrable et al 2018;Birrer et al 2022a), though only in cases where millilensing and microlensing are not extreme (see Goobar et al 2017;Yahalomi et al 2017;Foxley-Marrable et al 2018;Dhawan et al 2020). Additionally, SNe Ia have well-understood models of light-curve evolution (Hsiao et al 2007;Guy et al 2010;Saunders et al 2018;Leget et al 2020;Kenworthy et al 2021;Pierel et al 2022;Mandel et al 2022) that enable precise time-delay measurements using color curves, which removes the effects of macro-and achromatic microlensing (e.g., Pierel & Rodney 2019;Huber et al 2021;Rodney et al 2021;Pierel et al 2023). The first two spectroscopically confirmed multiply imaged SNe Ia were iPTF16geu (Goobar et al 2017) and SN Zwicky (Goobar et al 2023;Pierel et al 2023), but both had very short time delays of ∼0.25-1.5 days that precluded competitive H 0 measurements (Dhawan et al 2020;Pierel et al 2023).…”

“…Additionally, SNe Ia have well-understood models of light-curve evolution (Hsiao et al 2007;Guy et al 2010;Saunders et al 2018;Leget et al 2020;Kenworthy et al 2021;Pierel et al 2022;Mandel et al 2022) that enable precise time-delay measurements using color curves, which removes the effects of macro-and achromatic microlensing (e.g., Pierel & Rodney 2019;Huber et al 2021;Rodney et al 2021;Pierel et al 2023). The first two spectroscopically confirmed multiply imaged SNe Ia were iPTF16geu (Goobar et al 2017) and SN Zwicky (Goobar et al 2023;Pierel et al 2023), but both had very short time delays of ∼0.25-1.5 days that precluded competitive H 0 measurements (Dhawan et al 2020;Pierel et al 2023).…”

Retrospective Search for Strongly Lensed Supernovae in the DESI Legacy Imaging Surveys

“…Both happen to be Type Ia. However, both have subarcsecond Einstein radii, and thus short time delays of 1 day, which makes them unuseful for H 0 measurements (Dhawan et al 2020;Goobar et al 2022;Pierel et al 2023). Some cluster lenses have very long time delays (e.g., two decades for SN Requiem) and they generally have larger modeling uncertainties, but with different systematics compared with galaxy-scale lenses.…”