SN 2002ap, the hypernova of class Ic (original) (raw)
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The Optical/Near-Infrared Light Curves of SN 2002ap for the First 1.5 Years after Discovery
Astrophysical Journal, 2006
Supernova (SN) 2002ap in M74 was observed in the UBVRIJHKUBVRIJHKUBVRIJHK bands for the first 40 days following its discovery (2002 January 29) until it disappeared because of solar conjunction, and then in June after it reappeared. The magnitudes and dates of peak brightness in each band were determined. While the rate of increase of the brightness before the peak is almost independent of wavelength, the subsequent rate of decrease becomes smaller with wavelength from the UUU to the RRR band, and is constant at wavelengths beyond III. The photometric evolution is faster than in the well-known ``hypernovae'' SNe~1998bw and 1997ef, indicating that SN 2002ap ejected less mass. The bolometric light curve of SN 2002ap for the full period of observations was constructed. The absolute magnitude is found to be much fainter than that of SN 1998bw, but is similar to that of SN 1997ef, which lies at the faint end of the hypernova population. The bolometric light curve at the early epochs was best reproduced with the explosion of a C+O star that ejects 2.5M˜sun2.5~M_\sun2.5M˜sun with kinetic energy ErmK=4times1051rmergs˜E_{\rm K}=4\times 10^{51}~{\rm ergs}ErmK=4times1051rmergs˜. A comparison of the predicted brightness of SN 2002ap with that observed after solar conjunction may imply that gamma\gammagamma-ray deposition at the later epochs was more efficient than in the model. This may be due to an asymmetric explosion.
The light curves of type Ia Supernova 2008gy
arXiv (Cornell University), 2010
CCD BV RI photometry is presented for type Ia supernova 2008gy. The light curves match the template curves for fast-declining SN Ia, but the colors appear redder than average, and the SN may also be slightly subluminous. SN 2008gy is found to be located far outside the boundaries of three nearest galaxies, each of them has nearly equal probability to be the host galaxy.
Light Curve and Spectral Evolution of Type IIb Supernovae
Bulletin de la Société royale des sciences de Liège, 2018
Stripped-Envelope Supernovae constitute the sub-class of core-collapse supernovae that strip off their outer hydrogen envelope due to high stellar winds or due to interaction with a binary companion where mass transfer occurs as a result of Roche lobe overflow. We present here the photometric and spectroscopic analysis of a member of this class : SN 2015as classified as a type IIb supernova. Light curve features are similar to those of SN 2011fu while spectroscopic features are quite similar to those of SN 2008ax and SN 2011dh. Early epoch spectra have been modelled with SYN++ which indicates a photospheric velocity of 8500 km sec −1 and temperature of 6500K. Spectroscopic lines show transitioning from H to He features confirming it to be a type IIb supernova. Prominent oxygen and calcium emission features are indicative of the asymmetry of the ejecta. We also estimate the signal to noise ratio of the 3.6m telescope data. This telescope is located at ARIES, Devasthal, Nainital at an altitude of 2450m. We also show the comparison plots of spectra taken with a 2m and 4m class telescopes to enlighten the importance of spectral features displayed by bigger diameter telescopes.
Photometric and spectroscopic evolution of the Type IIP supernova SN 2004et
Monthly Notices of the Royal Astronomical Society, 2006
We present optical photometry and spectroscopy of the type IIP supernova SN 2004et that occurred in the nearby galaxy NGC 6946. The observations span a time range of 8 days to 541 days after explosion. The late time bolometric luminosity and the Hα luminosity in the nebular phase indicate that 0.06 ± 0.02M ⊙ of 56 Ni was synthesised during the explosion. The plateau luminosity, its duration and the expansion velocity of the supernova at the middle of the plateau indicate an explosion energy of E exp = 1.20 +0.38 −0.30 × 10 51 ergs. The late time light curve and the evolution of the [OI] and Hα emission line profiles indicate the possibility of an early dust formation in the supernova ejecta. The luminosity of [OI] 6300, 6364Å doublet, before the dust formation phase, is found to be comparable to that of SN 1987A at similar epochs, impling an oxygen mass in the range 1.5 − 2M ⊙ , and a main sequence mass of 20M ⊙ for the progenitor.
Monthly Notices of the Royal Astronomical Society, 2013
We present optical UBVRI photometry and medium-resolution spectroscopy of a transitional Type Ia supernova, SN 2009an, over the period −6 to ∼+150 d from the B maximum. With a m 15 (B) = 1.514 ± 0.132, SN 2009an declines faster than normal Type Ia events, but slower than the fast-declining, low-luminosity 1991bg-like events. The B-band absolute magnitude at maximum is −19.02 ± 0.20. The peak bolometric luminosity indicates that 0.41 M of 56 Ni was synthesized during the explosion. The pre-maximum and early post-maximum spectral evolution of SN 2009an is very similar to that in the transitional Type Ia SN 2004eo. Highvelocity features in the Ca II near-infrared triplet are seen during the early phases. Similar to the other few objects belonging to this class, SN 2009an exhibits a higher value (∼0.4) of the Si II line ratio R(Si II). The velocity gradient of the Si II 6355 Å line in the post-maximum epoch (v = 60 km s −1 d −1) is at the boundary between the low-velocity-gradient and high-velocitygradient groups.
Optical Photometry and Spectroscopy of the SN 1998bw-like Type Ic Supernova 2002ap
Publications of The Astronomical Society of The Pacific, 2003
We present optical photometric and spectral data of the peculiar Type Ic SN 2002ap. Photometric coverage includes UBVRI bands from 2002 January 30, the day after discovery, through 2002 December 12. There are 5 early-time spectra and 8 in the nebular phase. We determine that SN 2002ap is similar to SN 1997ef and the GRB-associated SN 1998bw with respect to spectral and photometric characteristics. The nebular spectra of SN 2002ap present the largest Mg I] \lambda 4571 to [O I] \lambda \lambda 6300, 6364 ratio of any supernova spectra yet published, suggesting that the progenitor of SN 2002ap was a highly stripped star. Comparing the nebular spectra of SN 1985F and SN 2002ap, we notice several similar features, casting the classification of SN 1985F as a normal Type Ib supernova in doubt. We also present nebular modeling of SN 2002ap and find that the object ejected >~ 1.5 M_{sun} of material within the outer velocity shell of the nebula (~5500 km/s) and synthesized ~0.09 M_{sun} of 56Ni.
Optical Light Curves of the Type I[CLC]a[/CLC] Supernovae SN 1990N and SN 1991T
The Astronomical Journal, 1998
We present UBVRI light curves for the bright Type Ia supernovae SN 1990N in NGC 4639 and SN 1991T in NGC 4527 based on photometry gathered in the course of the Calán/Tololo supernova program. Both objects have well-sampled light curves starting several days before maximum light and spanning well through the exponential tail. These data supercede the preliminary photometry published by . The host galaxies for these supernovae have (or will have) accurate distances based on the Cepheid period-luminosity relationship. The photometric data in this paper provide template curves for the study of general population of Type Ia supernova and accurate photometric indices needed for the Cepheid-supernova distance scale.
ESC observations of SN 2005cf - I. Photometric evolution of a normal Type Ia supernova
Monthly Notices of the Royal Astronomical Society, 2007
We present early-time optical and near-infrared photometry of supernova (SN) 2005cf. The observations, spanning a period from about 12 days before to 3 months after maximum, have been obtained through the coordination of observational efforts of various nodes of the European Supernova Collaboration and including data obtained at the 2m Himalayan Chandra Telescope. From the observed light curve we deduce that SN 2005cf is a fairly typical SN Ia with a post-maximum decline (∆m 15 (B) true = 1.12) close to the average value and a normal luminosity of M B,max =-19.39±0.33. Models of the bolometric light curve suggest a synthesised 56 Ni mass of about 0.7M ⊙. The negligible host galaxy interstellar extinction and its proximity make SN 2005cf a good Type Ia supernova template.
Monthly Notices of the Royal Astronomical Society, 2008
As part of the European Supernova Collaboration we obtained extensive photometry and spectroscopy of the type Ia SN 2002dj covering epochs from 11 days before to nearly two years after maximum. Detailed optical and near-infrared observations show that this object belongs to the class of the high-velocity gradient events as indicated by Si, S and Ca lines. The light curve shape and velocity evolution of SN 2002dj appear to be nearly identical to SN 2002bo. The only significant difference is observed in the optical to near-IR colours and a reduced spectral emission beyond 6500Å. For high-velocity gradient Type Ia supernovae, we tentatively identify a faster rise to maximum, a more pronounced inflection in the V and R light curves after maximum and a brighter, slower declining late-time B light curve as common photometric properties of this class of objects. They also seem to be characterized by a different colour and colour evolution with respect to "normal" SNe Ia. The usual light curve shape parameters do not distinguish these events. Stronger, more blueshifted absorption features of intermediate-mass elements and lower temperatures are the most prominent spectroscopic features of Type Ia supernovae displaying high velocity gradients. It appears that these events burn more intermediate-mass elements in the outer layers. Possible connections to the metallicity of the progenitor star are explored.
The Morphology of Type IA Supernovae Light Curves
The Astronomical Journal, 1996
We present a family of six BVI template light curves for SNe Ia for days-5 and +80, based on high-quality data gathered at CTIO. These templates display a wide range of light curve morphologies, with initial decline rates of their B light curves between m 15 (B)=0.87 m and 1.93 m. W e use these templates to study the general morphology of SNe Ia light curves. We nd that several of the main features of the BVI templates correlate tightly with m 15 (B). In particular, the V light curves, which are probably a reasonably good approximation of the bolometric light curves, display an orderly progression in shapes between the most-luminous, slowest-declining events and the least-luminous, fastest-declining SNe. This supports the idea that the observed spectroscopic and photometric sequences of SNe Ia are due primarily to one parameter. Nevertheless, SNe with very similar initial decline rates do show signicant dierences in their light curve properties when examined in detail, suggesting the inuence of one or more secondary parameters.