اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدRed and dead: The progenitor of SN 2012aw in M95
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Core-collapse supernovae (SNe) are the spectacular finale to massive stellar evolution. In this Letter, we identify a progenitor for the nearby core-collapse SN 2012aw in both ground based near-infrared, and space based optical pre-explosion imaging. The SN itself appears to be a normal Type II Plateau event, reaching a bolometric luminosity of 10$^{42}$ erg s$^{-1}$ and photospheric velocities of $sim$11,000 kms from the position of the H$beta$ P-Cygni minimum in the early SN spectra. We use an adaptive optics image to show that the SN is coincident to within 27 mas with a faint, red source in pre-explosion HST+WFPC2, VLT+ISAAC and NTT+SOFI images. The source has magnitudes $F555W$=26.70$pm$0.06, $F814W$=23.39$pm$0.02, $J$=21.1$pm$0.2, $K$=19.1$pm$0.4, which when compared to a grid of stellar models best matches a red supergiant. Interestingly, the spectral energy distribution of the progenitor also implies an extinction of $A_V>$1.2 mag, whereas the SN itself does not appear to be significantly extinguished. We interpret this as evidence for the destruction of dust in the SN explosion. The progenitor candidate has a luminosity between 5.0 and 5.6 log L/lsun, corresponding to a ZAMS mass between 14 and 26 msun (depending on $A_V$), which would make this one of the most massive progenitors found for a core-collapse SN to date.
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We present new late-time near-infrared imaging of the site of the nearby core-collapse supernova SN 2012aw, confirming the disappearance of the point source identified by Fraser et al. (2012) and Van Dyk et al. (2012) as a candidate progenitor in bot
h J and Ks filters. We re-measure the progenitor photometry, and find that both the J and Ks magnitudes of the source are consistent with those quoted in the literature. We also recover a marginal detection of the progenitor in H-band, for which we measure H=19.67+/-0.40 mag. Comparing the luminosity of the progenitor to stellar evolutionary models, SN 2012aw appears to have resulted from the explosion of a 12.5+/-1.5 Msun red supergiant.
We use natural seeing imaging of SN 2013ej in M74 to identify a progenitor candidate in archival {it Hubble Space Telescope} + ACS images. We find a source coincident with the SN in the {it F814W}-filter, however the position of the progenitor candid
ate in contemporaneous {it F435W} and {it F555W}-filters is significantly offset. We conclude that the progenitor candidate is in fact two physically unrelated sources; a blue source which is likely unrelated to the SN, and a red source which we suggest exploded as SN 2013ej. Deep images with the same instrument onboard {it HST} taken when the supernova has faded (in approximately two years time) will allow us to accurately characterise the unrelated neighbouring source and hence determine the intrinsic flux of the progenitor in three filters. We suggest that the {it F814W} flux is dominated by the progenitor of SN 2013ej, and assuming a bolometric correction appropriate to an M-type supergiant, we estimate that the mass of the progenitor of SN 2013ej was between 8 -- 15.5 M$_{odot}$.
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We report initial observations and analysis on the Type IIb SN~2016gkg in the nearby galaxy NGC~613. SN~2016gkg exhibited a clear double-peaked light curve during its early evolution, as evidenced by our intensive photometric follow-up campaign. SN~2
016gkg shows strong similarities with other Type IIb SNe, in particular with respect to the he~emission features observed in both the optical and near infrared. SN~2016gkg evolved faster than the prototypical Type~IIb SN~1993J, with a decline similar to that of SN~2011dh after the first peak. The analysis of archival {it Hubble Space Telescope} images indicate a pre-explosion source at SN~2016gkgs position, suggesting a progenitor star with a $sim$mid F spectral type and initial mass $15-20$msun, depending on the distance modulus adopted for NGC~613. Modeling the temperature evolution within $5,rm{days}$ of explosion, we obtain a progenitor radius of $sim,48-124$rsun, smaller than that obtained from the analysis of the pre-explosion images ($240-320$rsun).
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drodynamic model which simultaneously reproduced the photometry observations and velocity measurements. The model was calculated with the multi-energy group radiation hydrodynamics code STELLA. We found the parameters of the pre-supernova: radius $R = 500 R_odot$, nickel mass $M(^{56}$Ni$)$ $sim 0.06 M_odot$, pre-supernova mass $25 M_odot$, mass of ejected envelope $23.6 M_odot$, explosion energy $E sim 2 times 10^{51}$ erg. The model progenitor mass $M=25 M_odot$ significantly exceeds the upper limit mass $M=17 M_odot$, obtained from analysis the pre-SNe observations. This result confirms once more that the Red Supergiant Problem must be resolved by stellar evolution and supernova explosion theories in interaction with observations.
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