Browsing by Author "Stritzinger, M. D."

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    Expanding the parameter space of 2002es-like type Ia supernovae: On the underluminous ASASSN-20jq/SN 2020qxp
    (2025) Bose, S.; Stritzinger, M. D.; Ashall, C.; Baron, E.; Hoeflich, P.; Galbany, L.; Hoogendam, W. B.; Jensen, E. A. M.; Kochanek, C. S.; Post, R. S.; Reguitti, A.; Elias-Rosa, N.; Stanek, K. Z.; Lundqvist, P.; Auchettl, K.; Clocchiatti, Alejandro; Fiore, A.; Gutierrez, C. P.; Hinkle, J. T.; Huber, M. E.; de Jaeger, T.; Pastorello, A.; Payne, A. V.; Phillips, M.; Shappee, B. J.; Tucker, M. A.
    We present optical photometric and spectroscopic observations of the peculiar Type Ia supernovae (SNe Ia) ASASSN-20jq/SN 2020qxp. It is a low-luminosity object, with a peak absolute magnitude of M-B = -17.1 +/- 0.5 mag, while its post-peak light-curve decline rate of Delta m(15)(B) = 1.35 +/- 0.09 mag and color-stretch parameter of s(BV) & gap; 0.82 is similar to that of normal luminosity SNe Ia. That makes it a prevalent outlier in both the SN Ia luminosity-width and the luminosity-color-stretch relations. The analysis of the early light curves indicates a possible "bump" during the first approximate to 1.4 days of explosion. ASASSN-20jq synthesized a low radioactive Ni-56 mass of 0.09 +/- 0.01 M-circle dot. The near-maximum light spectra of the supernova show strong Si II absorption lines, indicating a cooler photosphere than normal SNe Ia; however, it lacks Ti II absorption lines. Additionally, it shows unusually strong absorption features of O I lambda 7773 and the Ca II near-infrared triplet. The nebular spectra of ASASSN-20jq show a remarkably strong but narrow forbidden [Ca II] lambda lambda 7291, 7324 doublet emission that has not been seen in SNe Ia except for a handful of Type Iax events. There is also a marginal detection of the [O I] lambda lambda 6300, 6364 doublet emission in nebular spectra, which is extremely rare. Both the [Ca II] and [O I] lines are redshifted by roughly 2000 km s(-1). ASASSN-20jq also exhibits a strong [Fe II] lambda 7155 emission line with a tilted-top line profile, which is identical to the [Fe II] lambda 16433 line profile. The asymmetric [Fe II] line profiles, along with the redshifted [Ca II] and emission lines, suggest a high central density white dwarf progenitor that underwent an off-center delayed-detonation explosion mechanism, synthesizing roughly equal amounts of Ni-56 during the deflagration and detonation burning phases. The equal production of Ni-56 in both burning phases distinguishes ASASSN-20jq from normal bright and subluminous SNe Ia. Assuming this scenario, we simultaneously modeled the optical and near-infrared nebular spectra, achieving a good agreement with the observations. The light curve and spectroscopic features of ASASSN-20jq do not align with any single sub-class of SNe Ia. However, the significant deviation from the luminosity versus light-curve shape relations (along with several light-curve and spectroscopic features) exhibits similarities to some 2002es-like objects. Therefore, we have identified ASASSN-20jq as an extreme candidate within the broad and heterogeneous parameter space of 2002es-like SNe Ia.
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    Luminous Type II supernovae for their low expansion velocities
    (2020) Rodríguez, O.; Pignata, Giuliano; Anderson, J. P.; Moriya, T. J.; Clocchiatti, Alejandro; Förster, F.; Prieto, J. L.; Phillips, M. M.; Burns, C. R.; Contreras, C.; Folatelli, G.; Gutiérrez, C. P.; Hamuy, M.; Morrell, N. I.; Stritzinger, M. D.; Suntzeff, N. B.; Benetti, S.; Cappellaro, E.; Elias Rosa, N.; Pastorello, A.; Turatto, M.; Maza, J.; Antezana, R.; Cartier, R.; González, L.; Haislip, J. B.; Kouprianov, V.; López, P.; Marchi Lasch, S.; Reichart, D.
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    Photometric and spectroscopic evolution of the interacting transient AT 2016jbu(Gaia16cfr)
    (2022) Brennan, S. J.; Fraser, M.; Johansson, J.; Pastorello, A.; Kotak, R.; Stevance, H. F.; Chen, T-W; Eldridge, J. J.; Bose, S.; Brown, P. J.; Callis, E.; Cartier, R.; Dennefeld, M.; Dong, Subo; Duffy, P.; Elias-Rosa, N.; Hosseinzadeh, G.; Hsiao, E.; Kuncarayakti, H.; Martin-Carrillo, A.; Monard, B.; Nyholm, A.; Pignata, G.; Sand, D.; Shappee, B. J.; Smartt, S. J.; Tucker, B. E.; Wyrzykowski, L.; Abbot, H.; Benetti, S.; Bento, J.; Blondin, S.; Chen, Ping; Delgado, A.; Galbany, L.; Gromadzki, M.; Gutierrez, C. P.; Hanlon, L.; Harrison, D. L.; Hiramatsu, D.; Hodgkin, S. T.; Holoien, T. W-S; Howell, D. A.; Inserra, C.; Kankare, E.; Kozlowski, S.; Muller-Bravo, T. E.; Maguire, K.; McCully, C.; Meintjes, P.; Morrell, N.; Nicholl, M.; O'Neill, D.; Pietrukowicz, P.; Poleski, R.; Prieto, J. L.; Rau, A.; Reichart, D. E.; Schweyer, T.; Shahbandeh, M.; Skowron, J.; Sollerman, J.; Soszynski, I; Stritzinger, M. D.; Szymanski, M.; Tartaglia, L.; Udalski, A.; Ulaczyk, K.; Young, D. R.; van Leeuwen, M.; van Soelen, B.
    We present the results from a high-cadence, multiwavelength observation campaign of AT 2016jbu (aka Gaia16cfr), an interacting transient. This data set complements the current literature by adding higher cadence as well as extended coverage of the light-curve evolution and late-time spectroscopic evolution. Photometric coverage reveals that AT 2016jbu underwent significant photometric variability followed by two luminous events, the latter of which reached an absolute magnitude of M-V similar to-18.5 mag. This is similar to the transient SN 2009ip whose nature is still debated. Spectra are dominated by narrow emission lines and show a blue continuum during the peak of the second event. AT 2016jbu shows signatures of a complex, non-homogeneous circumstellar material (CSM). We see slowly evolving asymmetric hydrogen line profiles, with velocities of 500 km s(-)(1) seen in narrow emission features from a slow-moving CSM, and up to 10 000 km s(-1) seen in broad absorption from some high-velocity material. Late-time spectra (similar to+1 yr) show a lack of forbidden emission lines expected from a core-collapse supernova and are dominated by strong emission from H, He I, and Ca II. Strong asymmetric emission features, a bumpy light curve, and continually evolving spectra suggest an inhibit nebular phase. We compare the evolution of H alpha among SN 2009ip-like transients and find possible evidence for orientation angle effects. The light-curve evolution of AT 2016jbu suggests similar, but not identical, circumstellar environments to other SN 2009ip-like transients.
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    Progenitor, environment, and modelling of the interacting transient AT 2016jbu (Gaia16cfr)
    (2022) Brennan, S. J.; Fraser, M.; Johansson, J.; Pastorello, A.; Kotak, R.; Stevance, H. F.; Chen, T-W; Eldridge, J. J.; Bose, S.; Brown, P. J.; Callis, E.; Cartier, R.; Dennefeld, M.; Dong, Subo; Duffy, P.; Elias-Rosa, N.; Hosseinzadeh, G.; Hsiao, E.; Kuncarayakti, H.; Martin-Carrillo, A.; Monard, B.; Pignata, G.; Sand, D.; Shappee, B. J.; Smartt, S. J.; Tucker, B. E.; Wyrzykowski, L.; Abbot, H.; Benetti, S.; Bento, J.; Blondin, S.; Chen, Ping; Delgado, A.; Galbany, L.; Gromadzki, M.; Gutierrez, C. P.; Hanlon, L.; Harrison, D. L.; Hiramatsu, D.; Hodgkin, S. T.; Holoien, T. W-S; Howell, D. A.; Inserra, C.; Kankare, E.; Kozlowski, S.; Muller-Bravo, T. E.; Maguire, K.; McCully, C.; Meintjes, P.; Morrell, N.; Nicholl, M.; O'Neill, D.; Pietrukowicz, P.; Poleski, R.; Prieto, J. L.; Rau, A.; Reichart, D. E.; Schweyer, T.; Shahbandeh, M.; Skowron, J.; Sollerman, J.; Soszynski, I; Stritzinger, M. D.; Szymanski, M.; Tartaglia, L.; Udalski, A.; Ulaczyk, K.; Young, D. R.; van Leeuwen, M.; van Soelen, B.
    We present the bolometric light curve, identification and analysis of the progenitor candidate, and preliminary modelling of AT 2016jbu (Gaia16cfr). We find a progenitor consistent with a similar to 22-25 M-circle dot yellow hypergiant surrounded by a dusty circumstellar shell, in agreement with what has been previously reported. We see evidence for significant photometric variability in the progenitor, as well as strong H alpha emission consistent with pre-existing circumstellar material. The age of the environment, as well as the resolved stellar population surrounding AT 2016jbu, supports a progenitor age of >10 Myr, consistent with a progenitor mass of similar to 22 M-circle dot. A joint analysis of the velocity evolution of AT 2016jbu and the photospheric radius inferred from the bolometric light curve shows the transient is consistent with two successive outbursts/explosions. The first outburst ejected material with velocity similar to 650 km s(-1), while the second, more energetic event ejected material at similar to 4500 km s(-1). Whether the latter is the core collapse of the progenitor remains uncertain. We place a limit on the ejected Ni-56 mass of <0.016 M-circle dot. Using the Binary Population And Spectral Synthesis (BPASS) code, we explore a wide range of possible progenitor systems and find that the majority of these are in binaries, some of which are undergoing mass transfer or common-envelope evolution immediately prior to explosion. Finally, we use the SuperNova Explosion Code (SNEC) to demonstrate that the low-energy explosions within some of these binary systems, together with sufficient circumstellar material, can reproduce the overall morphology of the light curve of AT 2016jbu.
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    The ASAS-SN bright supernova catalogue - V. 2018-2020
    (2023) Neumann, K. D.; Holoien, T. W-S; Kochanek, C. S.; Stanek, K. Z.; Vallely, P. J.; Shappee, B. J.; Prieto, J. L.; Pessi, T.; Jayasinghe, T.; Brimacombe, J.; Bersier, D.; Aydi, E.; Basinger, C.; Beacom, J. F.; Bose, S.; Brown, J. S.; Chen, P.; Clocchiatti, A.; Desai, D. D.; Dong, Subo; Falco, E.; Holmbo, S.; Morrell, N.; Shields, J. V.; Sokolovsky, K. V.; Strader, J.; Stritzinger, M. D.; Swihart, S.; Thompson, T. A.; Way, Z.; Aslan, L.; Bishop, D. W.; Bock, G.; Bradshaw, J.; Cacella, P.; Castro-Morales, N.; Conseil, E.; Cornect, R.; Cruz, I.; Farfan, R. G.; Fernandez, J. M.; Gabuya, A.; Gonzalez-Carballo, J-L; Kendurkar, M. R.; Kiyota, S.; Koff, R. A.; Krannich, G.; Marples, P.; Masi, G.; Monard, L. A. G.; Munoz, J. A.; Nicholls, B.; Post, R. S.; Pujic, Z.; Stone, G.; Tomasella, L.; Trappett, D. L.; Wiethoff, W. S.
    We catalogue the 443 bright supernovae (SNe) discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN) in 2018-2020 along with the 519 SNe recovered by ASAS-SN and 516 additional m(peak) <= 18 mag SNe missed by ASAS-SN. Our statistical analysis focuses primarily on the 984 SNe discovered or recovered in ASAS-SN g-band observations. The complete sample of 2427 ASAS-SN SNe includes earlier V-band samples and unrecovered SNe. For each SN, we identify the host galaxy, its UV to mid-IR photometry, and the SN's offset from the centre of the host. Updated peak magnitudes, redshifts, spectral classifications, and host galaxy identifications supersede earlier results. With the increase of the limiting magnitude to g <= 18 mag, the ASAS-SN sample is nearly complete up to m(peak) = 16.7 mag and is 90 per cent complete for m(peak) <= 17.0 mag. This is an increase from the V-band sample, where it was roughly complete up to m(peak) = 16.2 mag and 70 per cent complete for m(peak) <= 17.0 mag.