Do you want to publish a course? Click here

The Light Curve of the Unusual Supernova SN 2003dh

72   0   0.0 ( 0 )
 Added by Stan Woosley
 Publication date 2003
  fields Physics
and research's language is English
 Authors S. E. Woosley




Ask ChatGPT about the research

SN 2003dh, one of the most luminous supernovae ever recorded, and the one with the highest measured velocities, accompanied gamma-ray burst 030329. Its rapid rise to maximum and equally rapid decline pose problems for any spherically symmetric model. We model the supernova here as a very energetic, polar explosion that left the equatorial portions of the star almost intact. The total progenitor mass was much greater than the mass of high-velocity ejecta, and the total mass of 56-Ni synthesized was about 0.5 solar masses. Such asymmetries and nickel masses are expected in the collapsar model. A ``composite two-dimensional model is calculated that agrees well with the characteristics of the observed light curve. The mass of 56-Ni required for this light curve is 0.55 solar masses and the total explosion energy, 26 x 10**51 erg.



rate research

Read More

We present late-time optical $R$-band imaging data from the Palomar Transient Factory (PTF) for the nearby type Ia supernova SN 2011fe. The stacked PTF light curve provides densely sampled coverage down to $Rsimeq22$ mag over 200 to 620 days past explosion. Combining with literature data, we estimate the pseudo-bolometric light curve for this event from 200 to 1600 days after explosion, and constrain the likely near-infrared contribution. This light curve shows a smooth decline consistent with radioactive decay, except over ~450 to ~600 days where the light curve appears to decrease faster than expected based on the radioactive isotopes presumed to be present, before flattening at around 600 days. We model the 200-1600d pseudo-bolometric light curve with the luminosity generated by the radioactive decay chains of $^{56}$Ni, $^{57}$Ni and $^{55}$Co, and find it is not consistent with models that have full positron trapping and no infrared catastrophe (IRC); some additional energy escape other than optical/near-IR photons is required. However, the light curve is consistent with models that allow for positron escape (reaching 75% by day 500) and/or an IRC (with 85% of the flux emerging in non-optical wavelengths by day 600). The presence of the $^{57}$Ni decay chain is robustly detected, but the $^{55}$Co decay chain is not formally required, with an upper mass limit estimated at 0.014 M$_{odot}$. The measurement of the $^{57}$Ni/$^{56}$Ni mass ratio is subject to significant systematic uncertainties, but all of our fits require a high ratio >0.031 (>1.3 in solar abundances).
105 - Ori D. Fox 2015
SN 2006gy was the most luminous SN ever observed at the time of its discovery and the first of the newly defined class of superluminous supernovae (SLSNe). The extraordinary energetics of SN 2006gy and all SLSNe (>10^51 erg) require either atypically large explosion energies (e.g., pair-instability explosion) or the efficient conversion of kinetic into radiative energy (e.g., shock interaction). The mass-loss characteristics can therefore offer important clues regarding the progenitor system. For the case of SN 2006gy, both a scattered and thermal light echo from circumstellar material (CSM) have been reported at later epochs (day ~800), ruling out the likelihood of a pair-instability event and leading to constraints on the characteristics of the CSM. Owing to the proximity of the SN to the bright host-galaxy nucleus, continued monitoring of the light echo has not been trivial, requiring the high resolution offered by the Hubble Space Telescope (HST) or ground-based adaptive optics (AO). Here we report detections of SN 2006gy using HST and Keck AO at ~3000 days post-explosion and consider the emission mechanism for the very late-time light curve. While the optical light curve and optical spectral energy distribution are consistent with a continued scattered-light echo, a thermal echo is insufficient to power the K-band emission by day 3000. Instead, we present evidence for late-time infrared emission from dust that is radiatively heated by CSM interaction within an extremely dense dust shell, and we consider the implications on the CSM characteristics and progenitor system.
We present the $UBVR_cI_c$ broad band optical photometry of the Type Ic supernova SN 2002ap obtained during 2002 February 06 -- March 23 in the early decline phases and also later on 2002 15 August. Combining these data with the published ones, the general light curve development is studied. The time and luminosity of the peak brightness and the peak width are estimated. There is a flattening in the optical light curve about 30 days after the $B$ maximum. The flux decline rates before flattening are 0.127$pm$0.005, 0.082$pm$0.001, 0.074$pm$0.001, 0.062$pm$0.001 and 0.040$pm$0.001 mag day$^{-1}$ in $U$, $B$, $V$, $R_c$ and $I_c$ passbands respectively, while the corresponding values after flattening are about 0.02 mag day$^{-1}$ in all the passbands. The maximum brightness of SN 2002ap $M_V = - 17.2$ mag, is comparable to that of the type Ic 1997ef, but fainter than that of the type Ic hypernova SN 1998bw. The peak luminosity indicates an ejection of $sim$ 0.06 M$_{odot}$ ${}^{56}$Ni mass. We also present low-resolution optical spectra obtained during the early phases. The SiII absorption minimum indicates that the photospheric velocity decreased from $sim$ 21,360 km s$^{-1}$ to $sim$ 10,740 km s$^{-1}$ during a period of $sim$ 6 days.
332 - K.L. Page 2009
Swift-detected GRB 080307 showed an unusual smooth rise in its X-ray light-curve around 100 seconds after the burst, at the start of which the emission briefly softened. This `hump has a longer duration than is normal for a flare at early times and does not demonstrate a typical flare profile. Using a two component power-law-to-exponential model, the rising emission can be modelled as the onset of the afterglow, something which is very rarely seen in Swift-X-ray light-curves. We cannot, however, rule out that the hump is a particularly slow early-time flare, or that it is caused by upscattered reverse shock electrons.
We present results of the photometric (from 3 to 509 days past explosion) and spectroscopic (up to 230 days past explosion) monitoring campaign of the He-rich Type IIb supernova (SN) 2015as. The {it (B-V)} colour evolution of SN 2015as closely resemble those of SN 2008ax, suggesting that SN 2015as belongs to the SN IIb subgroup that does not show the early, short-duration photometric peak. The light curve of SN 2015as reaches the $B$-band maximum about 22 days after the explosion, at an absolute magnitude of -16.82 $pm$ 0.18 mag. At $sim$ 75 days after the explosion, its spectrum transitions from that of a SN II to a SN Ib. P~Cygni features due to He I lines appear at around 30 days after explosion, indicating that the progenitor of SN 2015as was partially stripped. For SN~2015as, we estimate a $^{56}$Ni mass of $sim$ 0.08 M$_{odot}$ and ejecta mass of 1.1--2.2 M$_{odot}$, which are similar to the values inferred for SN 2008ax. The quasi bolometric analytical light curve modelling suggests that the progenitor of SN 2015as has a modest mass ($sim$ 0.1 M$_{odot}$), a nearly-compact ($sim$ 0.05$times$10$^{13}$ cm) H envelope on top of a dense, compact ($sim$ 2$times$10$^{11}$ cm) and a more massive ($sim$ 1.2 M$_{odot}$) He core. The analysis of the nebular phase spectra indicates that $sim$ 0.44 M$_{odot}$ of O is ejected in the explosion. The intensity ratio of the [Ca II]/[O I] nebular lines favours either a main sequence progenitor mass of $sim$ 15 M$_{odot}$ or a Wolf Rayet star of 20 M$_{odot}$.
comments
Fetching comments Fetching comments
Sign in to be able to follow your search criteria
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا