分类： 天文学 >> 天文学 提交时间： 2023-02-19
Lindsey A. Kwok
Saurabh W. Jha
Tea Temim
Ori D. Fox
Conor Larison
Yssavo Camacho-Neves
Max J. Brenner Newman
Justin D. R. Pierel
Ryan J. Foley
Jennifer E. Andrews
Carles Badenes
Barnabas Barna
K. Azalee Bostroem
Maxime Deckers
Andreas Flors
Peter Garnavich
Melissa L. Graham
Or Graur
Griffin Hosseinzadeh
D. Andrew Howell
摘要： We present JWST near- and mid-infrared spectroscopic observations of the nearby normal Type Ia supernova SN 2021aefx in the nebular phase at $+255$ days past maximum light. Our Near Infrared Spectrograph (NIRSpec) and Mid Infrared Instrument (MIRI) observations, combined with ground-based optical data from the South African Large Telescope (SALT), constitute the first complete optical $+$ NIR $+$ MIR nebular SN Ia spectrum covering 0.3$-$14 $\mu$m. This spectrum unveils the previously unobserved 2.5$-$5 $\mu$m region, revealing strong nebular iron and stable nickel emission, indicative of high-density burning that can constrain the progenitor mass. The data show a significant improvement in sensitivity and resolution compared to previous Spitzer MIR data. We identify numerous NIR and MIR nebular emission lines from iron-group elements and as well as lines from the intermediate-mass element argon. The argon lines extend to higher velocities than the iron-group elements, suggesting stratified ejecta that are a hallmark of delayed-detonation or double-detonation SN Ia models. We present fits to simple geometric line profiles to features beyond 1.2 $\mu$m and find that most lines are consistent with Gaussian or spherical emission distributions, while the [Ar III] 8.99 $\mu$m line has a distinctively flat-topped profile indicating a thick spherical shell of emission. Using our line profile fits, we investigate the emissivity structure of SN 2021aefx and measure kinematic properties. Continued observations of SN 2021aefx and other SNe Ia with JWST will be transformative to the study of SN Ia composition, ionization structure, density, and temperature, and will provide important constraints on SN Ia progenitor and explosion models.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Ness Mayker Chen
Michael A. Tucker
Nils Hoyer
Saurabh W. Jha
Lindsey Kwok
Adam K. Leroy
Erik Rosolowsky
Chris Ashall
Gagandeep Anand
Frank Bigiel
Médéric Boquien
Chris Burns
Daniel Dale
James M. DerKacy
Oleg V. Egorov
L. Galbany
Kathryn Grasha
Hamid Hassani
Peter Hoeflich
Eric Hsiao
摘要： We present new 0.3-21 micron photometry of SN 2021aefx in the spiral galaxy NGC 1566 at +357 days after B-band maximum, including the first detection of any SN Ia at >15 micron. These observations follow earlier JWST observations of SN 2021aefx at +255 days after the time of maximum brightness, allowing us to probe the temporal evolution of the emission properties. We measure the fraction of flux emerging at different wavelengths and its temporal evolution. Additionally, the integrated 0.3-14 micron decay rate of $\Delta m_{0.3-14} = 1.35 \pm 0.05$ mag/100 days is higher than the decline rate from the radioactive decay of $^{56}$Co of $\sim 1.2$mag/100 days. The most plausible explanation for this discrepancy is that flux is shifting to >14 micron, and future JWST observations of SNe Ia will be able to directly test this hypothesis. However, models predicting non-radiative energy loss cannot be excluded with the present data.
点击量
待评议
点击量
下载量
评论
