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Seeing Double: ASASSN-18bt Exhibits a Two-component Rise in the Early-time K2 Light Curve

التفاصيل البيبلوغرافية
العنوان: Seeing Double: ASASSN-18bt Exhibits a Two-component Rise in the Early-time K2 Light Curve
المؤلفون: B. J. Shappee, T. W.-S. Holoien, M. R. Drout, K. Auchettl, M. D. Stritzinger, C. S. Kochanek, K. Z. Stanek, E. Shaya, G. Narayan, J. S. Brown, S. Bose, D. Bersier, J. Brimacombe, Ping Chen, Subo Dong, S. Holmbo, B. Katz, J. A. Munoz, R. L. Mutel, R. S. Post, J. L. Prieto, J. Shields, D. Tallon, T. A. Thompson, P. J. Vallely, S. Villanueva Jr, L. Denneau, H. Flewelling, A. N. Heinze, K. W. Smith, B. Stalder, J. L. Tonry, H. Weiland, T. Barclay, G. Barentsen, A. M. Cody, J. Dotson, F. Foerster, P. Garnavich, M. Gully-Santiago, C. Hedges, S. Howell, D. Kasen, S. Margheim, R. Mushotzky, A. Rest, B. E. Tucker, A. Villar, A. Zenteno, G. Beerman, R. Bjella, G. Castillo, J. Coughlin, B. Elsaesser, S. Flynn, R. Gangopadhyay, K. Griest, M. Hanley, J. Kampmeier, R. Kloetzel, L. Kohnert, C. Labonde, R. Larsen, K. A. Larson, K. M. McCalmont-Everton, C. McGinn, L. Migliorini, J. Moffatt, M. Muszynski, V. Nystrom, D. Osborne, M. Packard, C. A. Peterson, M. Redick, L. H. Reedy, S. E. Ross, B. Spencer, K. Steward, J. E. Van Cleve, J. Vinícius de Miranda-Cardoso, T. Weschler, A. Wheaton, J. Bulger, K. C. Chambers, H. A. Flewelling, M. E. Huber, T. B. Lowe, E. A. Magnier, A. S. B. Schultz, C. Z. Waters, M. Willman, E. Baron, Zhihao Chen, James M. Derkacy, Fang Huang, Linyi Li, Wenxiong Li, Xue Li, Jun Mo, Liming Rui, Hanna Sai, Lifan Wang, Lingzhi Wang, Xiaofeng Wang, Danfeng Xiang, Jicheng Zhang, Jujia Zhang, Kaicheng Zhang, Tianmeng Zhang, Xinghan Zhang, Xulin Zhao, P. J. Brown, J. J. Hermes, J. Nordin, S. Points, A. Sodor, G. M. Strampelli
المصدر: The Astrophysical Journal. 870(1)
بيانات النشر: United States: NASA Center for Aerospace Information (CASI), 2018.
سنة النشر: 2018
مصطلحات موضوعية: Astrophysics
الوصف: On 2018 February 4.41, the All-Sky Automated Survey for SuperNovae (ASAS-SN) discovered ASASSN-18bt in the K2 Campaign 16 field. With a redshift of z=0.01098 and a peak apparent magnitude of B(max)=14.31, ASASSN-18bt is the nearest and brightest SNe Ia yet observed by the Kepler spacecraft. Here we present the discovery of ASASSN-18bt, the K2 light curve, and prediscovery data from ASAS-SN and the Asteroid Terrestrial-impact Last Alert System. The K2 early-time light curve has an unprecedented 30-minute cadence and photometric precision for an SN Ia light curve, and it unambiguously shows a ∼4 day nearly linear phase followed by a steeper rise. Thus, ASASSN-18bt joins a growing list of SNe Ia whose early light curves are not well described by a single power law. We show that a double-power-law model fits the data reasonably well, hinting that two physical processes must be responsible for the observed rise. However, we find that current models of the interaction with a nondegenerate companion predict an abrupt rise and cannot adequately explain the initial, slower linear phase. Instead, we find that existing published models with shallow 56Ni are able to span the observed behavior and, with tuning, may be able to reproduce the ASASSN-18bt light curve. Regardless, more theoretical work is needed to satisfactorily model this and other early-time SNe Ia light curves. Finally, we use Swift X-ray nondetections to constrain the presence of circumstellar material (CSM) at much larger distances and lower densities than possible with the optical light curve. For a constant-density CSM, these nondetections constrain ρ<4.5×10(exp 5)per cu.cm at a radius of 4×10(exp 15) cm from the progenitor star. Assuming a wind-like environment, we place mass loss limits of M˙ < 8 x 10(exp -6) M(ʘ)per yr for v(w)=100 km/s, ruling out some symbiotic progenitor systems. This work highlights the power of well-sampled early-time data and the need for immediate multiband, high-cadence follow-up for progress in understanding SNe Ia.
نوع الوثيقة: Report
اللغة: English
تدمد: 1538-4357
0004-637X
DOI: 10.3847/1538-4357/aaec79
الوصول الحر: https://ntrs.nasa.gov/citations/20205004144Test
ملاحظات: 80GSFC17M0002

HF-51348.001

NAS 5-26555

AST-1515876

AST-1515927

NNX16AB25G

DGE- 1343012

GBMF5490

AST-0908816
رقم الانضمام: edsnas.20205004144
قاعدة البيانات: NASA Technical Reports
الوصف
تدمد:15384357
0004637X
DOI:10.3847/1538-4357/aaec79