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تسجيل مستخدم جديدThe double-peaked type Ic Supernova 2019cad: another SN 2005bf-like object
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We present the photometric and spectroscopic evolution of supernova (SN) 2019cad during the first $sim100$ days from explosion. Based on the light curve morphology, we find that SN 2019cad resembles the double-peaked type Ib/c SN 2005bf and the type Ic PTF11mnb. Unlike those two objects, SN 2019cad also shows the initial peak in the redder bands. Inspection of the g-band light curve indicates the initial peak is reached in $sim8$ days, while the r band peak occurred $sim15$ days post-explosion. A second and more prominent peak is reached in all bands at $sim45$ days past explosion, followed by and fast decline from $sim60$ days. During the first 30 days, the spectra of SN 2019cad show the typical features of a type Ic SN, however, after 40 days, a blue continuum with prominent lines of Si II ${lambda}6355$ and C II ${lambda}6580$ is observed again. Comparing the bolometric light curve to hydrodynamical models, we find that SN 2019cad is consistent with a pre-SN mass of 11 M$_{odot}$, and an explosion energy of $3.5times 10^{51}$ erg. The light curve morphology can be reproduced either by a double-peaked $^{56}$Ni distribution with an external component of 0.041 M$_{odot}$ and an internal component of 0.3 M$_{odot}$ or a double-peaked $^{56}$Ni distribution plus magnetar model (P $sim11$ ms and B $sim26times 10^{14}$ G). If SN 2019cad were to suffer from significant host reddening (which cannot be ruled out), the $^{56}$Ni model would require extreme values, while the magnetar model would still be feasible.
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