ترغب بنشر مسار تعليمي؟ اضغط هنا

Optical and Near-Infrared Observations of the Highly Reddened, Rapidly Expanding Type Ia Supernova 2006X in M100

429   0   0.0 ( 0 )
 نشر من قبل Xiaofeng Wang Dr.
 تاريخ النشر 2007
  مجال البحث فيزياء
والبحث باللغة English
 تأليف Xiaofeng Wang




اسأل ChatGPT حول البحث

We present extensive optical (UBVRI), near-infrared (JK) light curves and optical spectroscopy of the Type Ia supernova (SN) 2006X in the nearby galaxy NGC 4321 (M100). Our observations suggest that either SN 2006X has an intrinsically peculiar color evolution, or it is highly reddened [E(B - V)_{host} = 1.42+/-0.04 mag] with R_V = 1.48+/-0.06, much lower than the canonical value of 3.1 for the average Galactic dust. SN 2006X also has one of the highest expansion velocities ever published for a SN Ia. Compared with the other SNe Ia we analyzed, SN 2006X has a broader light curve in the U band, a more prominent bump/shoulder feature in the V and R bands, a more pronounced secondary maximum in the I and near-infrared bands, and a remarkably smaller late-time decline rate in the B band. The B - V color evolution shows an obvious deviation from the Lira-Phillips relation at 1 to 3 months after maximum brightness. At early times, optical spectra of SN 2006X displayed strong, high-velocity features of both intermediate-mass elements (Si, Ca, and S) and iron-peak elements, while at late times they showed a relatively blue continuum, consistent with the blue U-B and B-V colors at similar epochs. A light echo and/or the interaction of the SN ejecta and its circumstellar material may provide a plausible explanation for its late-time photometric and spectroscopic behavior. Using the Cepheid distance of M100, we derive a Hubble constant of 72.7+/-8.2 km s^{-1} Mpc^{-1}(statistical) from the normalized dereddened luminosity of SN 2006X. We briefly discuss whether abnormal dust is a universal signature for all SNe Ia, and whether the most rapidly expanding objects form a subclass with distinct photometric and spectroscopic properties.



قيم البحث

اقرأ أيضاً

184 - T. Zhang , X. Wang , W. Li 2009
We present optical photometry and spectra for the Type Ia supernova (SN Ia) 2007gi in the nearby galaxy NGC 4036. SN 2007gi is characterized by extremely high-velocity (HV) features of the intermediate-mass elements (Si, Ca, and S), with expansion ve locities ($v_{rm exp}$) approaching $sim$15,500 km s$^{-1}$ near maximum brightness (compared to $sim$10,600 km s$^{-1}$ for SNe Ia with normal $v_{rm exp}$). SN 2007gi reached a $B$-band peak magnitude of 13.25$pm$0.04 mag with a decline rate of $Delta m_{15}(B)$(true) = 1.33$pm$0.09 mag. The $B$-band light curve of SN 2007gi demonstrated an interesting two-stage evolution during the nebular phase, with a decay rate of 1.16$pm$0.05 mag (100 days)$^{-1}$ during $t = 60$--90 days and 1.61$pm0.04$ mag (100 days)$^{-1}$ thereafter. Such a behavior was also observed in the HV SN Ia 2006X, and might be caused by the interaction between supernova ejecta and circumstellar material (CSM) around HV SNe Ia. Based on a sample of a dozen well-observed $R$-band (or unfiltered) light curves of SNe Ia, we confirm that the HV events may have a faster rise time to maximum than the ones with normal $v_{rm exp}$.
105 - Masayuki Yamanaka 2009
We present optical spectroscopic and photometric observations of Type Ia supernova (SN) 2006X from --10 to +91 days after the $B$-band maximum. This SN exhibits one of the highest expansion velocity ever published for SNe Ia. At premaximum phases, th e spectra show strong and broad features of intermediate-mass elements such as Si, S, Ca, and Mg, while the O{sc i}$lambda$7773 line is weak. The extremely high velocities of Si{sc ii} and S{sc ii} lines and the weak O{sc i} line suggest that an intense nucleosynthesis might take place in the outer layers, favoring a delayed detonation model. Interestingly, Si{sc ii}$lambda$5972 feature is quite shallow, resulting in an unusually low depth ratio of Si{sc ii}$lambda$5972 to $lambda$6355, $cal R$(Si{sc ii}). The low $cal R$(Si{sc ii}) is usually interpreted as a high photospheric temperature. However, the weak Si{sc iii}$lambda$4560 line suggests a low temperature, in contradiction to the low $cal R$(Si{sc ii}). This could imply that the Si{sc ii}$lambda$5972 line might be contaminated by underlying emission. We propose that $cal R$(Si{sc ii}) may not be a good temperature indicator for rapidly expanding SNe Ia at premaximum phases.
We presented optical and near-infrared multi-band linear polarimetry of the highly reddened Type Ia SN~2014J appeared in M82. SN~2014J exhibits large polarization at shorter wavelengths, e.g., $4.8$% in $B$ band, and the polarization decreases rapidl y at longer wavelengths, with the position angle of the polarization remaining at approximately $40^{circ}$ over the observed wavelength range. These polarimetric properties suggest that the observed polarization is likely to be caused predominantly by the interstellar dust within M82. Further analysis shows that the polarization peaks at a wavelengths much shorter than those obtained for the Galactic dust. The wavelength dependence of the polarization can be better described by an inverse power law rather than by Serkowski law for Galactic interstellar polarization. These suggests that the nature of the dust in M82 may be different from that in our Galaxy, with polarizing dust grains having a mean radius of $<0.1 mu$m.
We present space-based ultraviolet/optical photometry and spectroscopy with the Swift Ultra-Violet/Optical Telescope and Hubble Space Telescope, respectively, along with ground-based optical photometry and spectroscopy and near-infrared spectroscopy of supernova SN2017erp. The optical light curves and spectra are consistent with a normal Type Ia supernova (SN Ia). Compared to previous photometric samples in the near-ultraviolet (NUV), SN2017erp has colors similar to the NUV-red category after correcting for Milky Way and host dust reddening. We find the difference between SN2017erp and the NUV-blue SN2011fe is not consistent with dust reddening alone but is similar to the SALT color law, derived from rest-frame UV photometry of higher redshift SNe Ia. This chromatic difference is dominated by the intrinsic differences in the UV and only a small contribution from the expected dust reddening. Differentiating the two can have important consequences for determining cosmological distances with rest-frame UV photometry. This spectroscopic series is important for analyzing SNe Ia with intrinsically redder NUV colors. We also show model comparisons suggesting that metallicity could be the physical difference between NUV-blue and NUV-red SNe Ia, with emission peaks from reverse fluorescence near 3000 Angstroms implying a factor of ten higher metallicity in the upper layers of SN2017erp compared to SN~2011fe. Metallicity estimates are very model dependent however, and there are multiple effects in the UV. Further models and UV spectra of SNe Ia are needed to explore the diversity of SNe Ia which show seemingly independent differences in the near-UV peaks and mid-UV flux levels.
145 - Xiaofeng Wang 2008
We report the discovery of a light echo (LE) from the Type Ia supernova (SN) 2006X in the nearby galaxy M100. The presence of the LE is supported by analysis of both the Advanced Camera for Surveys (ACS) images taken with the {it Hubble Space Telesco pe (HST)} at $sim$300 d after maximum brightness and the Keck optical spectrum obtained at a similar phase. In the image procedure, both the radial-profile analysis and the point-spread-function (PSF) subtraction method resolve significant excess emission at 2--5 ACS pixels ($sim0.05-0.13$) from the center. In particular, the PSF-subtracted ACS images distinctly appear to have an extended, ring-like echo. Due to limitations of the image resolution, we cannot confirm any structure or flux within 2 ACS pixels from the SN. The late-time spectrum of SN 2006X can be reasonably fit with two components: a nebular spectrum of a normal SN Ia and a synthetic LE spectrum. Both image and spectral analysis show a rather blue color for the emission of the LE, suggestive of a small average grain size for the scattering dust. Using the Cepheid distance to M100 of 15.2 Mpc, we find that the dust illuminated by the resolved LE is $sim$27--170 pc from the SN. The echo inferred from the nebular spectrum appears to be more luminous than that resolved in the images (at the $sim2sigma$ level), perhaps suggesting the presence of an inner echo at $<$2 ACS pixels ($sim0.05$). It is not clear, however, whether this possible local echo was produced by a distinct dust component (i.e., the local circumstellar dust) or by a continuous, larger distribution of dust as with the outer component. Nevertheless, our detection of a significant echo in SN 2006X confirms that this supernova was produced in a dusty environment having unusual dust properties.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا