scholarly journals Type Ia Supernovae Strongly Interacting with Their Circumstellar Medium

2015 ◽  
Vol 11 (A29B) ◽  
pp. 237-237
Author(s):  
Jeffrey M. Silverman ◽  
Peter Nugent ◽  
Avishay Gal-Yam ◽  
D. A. Howell ◽  
Mark Sullivan ◽  
...  
Keyword(s):  
Infrared Emission ◽  
Type Ia Supernovae ◽  
Host Galaxies ◽  
Ultraviolet Emission ◽  
Maximum Brightness ◽  
Type Ia ◽  
Hα Emission ◽  
Absolute Magnitudes ◽  
Ia Supernovae ◽  
Circumstellar Medium

AbstractA rare subclass of Type Ia supernovae (SNe Ia) shows evidence of strong interaction with a hydrogen-rich circumstellar medium (CSM); these objects are referred to as SNe Ia-CSM. PTF11kx began life as a SN Ia, but after a month it began to show indications of significant interaction with its CSM. This well-studied object solidified the connection between SNe Ia-CSM and more typical SNe Ia, despite their spectral similarity to Type IIn SNe (which likely come from massive star progenitors, as opposed to the white dwarf progenitors for the SNe Ia-CSM). The spectra of all ~20 known SNe Ia-CSM are dominated by Hα emission (with widths of ~2000 km s−1) and exhibit large Hα/Hβ intensity ratios; moreover, they have an almost complete lack of He I emission (see left panel of Figure 1). They also show possible evidence of dust formation through a decrease in the red wing of Hα 75–100 days past maximum brightness. The absolute magnitudes of SNe Ia-CSM are found to be -21.3 mag ≤ MR ≤ −19 mag (see right panel of Figure 1), and they also show ultraviolet emission at early times and strong infrared emission at late times (but no detected radio or X-ray emission). Finally, the host galaxies of SNe Ia-CSM imply that these objects come from a relatively young stellar population.

scholarly journals Towards a 1% measurement of the Hubble constant: accounting for time dilation in variable-star light curves

2019 ◽  
Vol 631 ◽  
pp. A165
Author(s):  
Richard I. Anderson
Keyword(s):  
Variable Star ◽  
Hubble Constant ◽  
Light Curves ◽  
Type Ia Supernovae ◽  
Host Galaxies ◽  
Pulsating Stars ◽  
Distant Galaxies ◽  
Type Ia ◽  
Absolute Magnitudes ◽  
Ia Supernovae

Assessing the significance and implications of the recently established Hubble tension requires the comprehensive identification, quantification, and mitigation of uncertainties and/or biases affecting H0 measurements. Here, we investigate the previously overlooked distance scale bias resulting from the interplay between redshift and Leavitt laws in an expanding Universe: Redshift-Leavitt bias (RLB). Redshift dilates oscillation periods of pulsating stars residing in supernova-host galaxies relative to periods of identical stars residing in nearby (anchor) galaxies. Multiplying dilated log P with Leavitt Law slopes leads to underestimated absolute magnitudes, overestimated distance moduli, and a systematic error on H0. Emulating the SH0ES distance ladder, we estimate an associated H0 bias of (0.27 ± 0.01)% and obtain a corrected H0 = 73.70 ± 1.40 km s−1 Mpc−1. RLB becomes increasingly relevant as distance ladder calibrations pursue greater numbers of ever more distant galaxies hosting both Cepheids (or Miras) and type-Ia supernovae. The measured periods of oscillating stars can readily be corrected for heliocentric redshift (e.g. of their host galaxies) in order to ensure H0 measurements free of RLB.

scholarly journals THE ABSOLUTE MAGNITUDES OF TYPE Ia SUPERNOVAE IN THE ULTRAVIOLET

2010 ◽  
Vol 721 (2) ◽  
pp. 1608-1626 ◽  
Author(s):  
Peter J. Brown ◽  
Peter W. A. Roming ◽  
Peter Milne ◽  
Filomena Bufano ◽  
Robin Ciardullo ◽  
...  
Keyword(s):  
Type Ia Supernovae ◽  
Type Ia ◽  
The Absolute ◽  
Absolute Magnitudes ◽  
Ia Supernovae

scholarly journals Linear spectropolarimetry of 35 Type Ia supernovae with VLT/FORS: an analysis of the Si ii line polarization

2019 ◽  
Vol 490 (1) ◽  
pp. 578-599 ◽  
Author(s):  
Aleksandar Cikota ◽  
Ferdinando Patat ◽  
Lifan Wang ◽  
J Craig Wheeler ◽  
Mattia Bulla ◽  
...  
Keyword(s):  
Type Ia Supernovae ◽  
Maximum Brightness ◽  
Numerical Predictions ◽  
Very Large Telescope ◽  
Type Ia ◽  
Supernova Explosions ◽  
Statistical Sample ◽  
Ia Supernovae ◽  
Low Dispersion ◽  
Detonation Model

ABSTRACT Spectropolarimetry enables us to measure the geometry and chemical structure of the ejecta in supernova explosions, which is fundamental for the understanding of their explosion mechanism(s) and progenitor systems. We collected archival data of 35 Type Ia supernovae (SNe Ia), observed with Focal Reducer and Low-Dispersion Spectrograph (FORS) on the Very Large Telescope at 127 epochs in total. We examined the polarization of the Si ii λ6355 Å line ($p_{\rm Si\, \small {II}}$) as a function of time, which is seen to peak at a range of various polarization degrees and epochs relative to maximum brightness. We reproduced the $\Delta m_{15}\!-\!p_{\rm Si\, \small {II}}$ relationship identified in a previous study, and show that subluminous and transitional objects display polarization values below the $\Delta m_{15}\!-\!p_{\rm Si\, \small {II}}$ relationship for normal SNe Ia. We found a statistically significant linear relationship between the polarization of the Si ii λ6355 Å line before maximum brightness and the Si ii line velocity and suggest that this, along with the $\Delta m_{15}\!-\!p_{\rm Si\, \small {II}}$ relationship, may be explained in the context of a delayed-detonation model. In contrast, we compared our observations to numerical predictions in the $\Delta m_{15}\!-\!v_{\rm Si\, \small {II}}$ plane and found a dichotomy in the polarization properties between Chandrasekhar and sub-Chandrasekhar mass explosions, which supports the possibility of two distinct explosion mechanisms. A subsample of SNe displays evolution of loops in the q–u plane that suggests a more complex Si structure with depth. This insight, which could not be gleaned from total flux spectra, presents a new constraint on explosion models. Finally, we compared our statistical sample of the Si ii polarization to quantitative predictions of the polarization levels for the double-detonation, delayed-detonation, and violent-merger models.

scholarly journals The dependence of Type Ia Supernovae luminosities on their host galaxies

2010 ◽  
pp. no-no ◽  
Author(s):  
M. Sullivan ◽  
A. Conley ◽  
D. A. Howell ◽  
J. D. Neill ◽  
P. Astier ◽  
...  
Keyword(s):  
Type Ia Supernovae ◽  
Host Galaxies ◽  
Type Ia ◽  
Ia Supernovae

scholarly journals Theoretical Light Curves for Type Ia Supernovae and Determination of the Hubble Constant

1999 ◽  
Vol 183 ◽  
pp. 68-68
Author(s):  
Koichi Iwamoto ◽  
Ken'Ichi Nomoto
Keyword(s):  
Hubble Constant ◽  
Light Curves ◽  
Type Ia Supernovae ◽  
Maximum Brightness ◽  
Decline Rate ◽  
Type Ia ◽  
Error Bars ◽  
Ia Supernovae ◽  
Distance Indicators

The large luminosity (MV ≈ −19 ∼ −20) and the homogeneity in light curves and spectra of Type Ia supernovae(SNe Ia) have led to their use as distance indicators ultimately to determine the Hubble constant (H0). However, an increasing number of the observed samples from intermediate- and high-z (z ∼ 0.1 − 1) SN Ia survey projects(Hamuy et al. 1996, Perlmutter et al. 1997) have shown that there is a significant dispersion in the maximum brightness (∼ 0.4 mag) and the brighter-slower correlation between the brightness and the postmaximum decline rate, which was first pointed out by Phillips(1993). By taking the correlation into account, Hamuy et al.(1996) gave an estimate of H0 within the error bars half as much as previous ones.

scholarly journals The Carnegie Supernova Project-I: Correlation between Type Ia Supernovae and Their Host Galaxies from Optical to Near-infrared Bands

2020 ◽  
Vol 901 (2) ◽  
pp. 143 ◽  
Author(s):  
Syed A Uddin ◽  
Christopher R. Burns ◽  
M. M. Phillips ◽  
Nicholas B. Suntzeff ◽  
Carlos Contreras ◽  
...  
Keyword(s):  
Near Infrared ◽  
Type Ia Supernovae ◽  
Host Galaxies ◽  
Type Ia ◽  
Ia Supernovae

scholarly journals OPTICAL IDENTIFICATION OF CEPHEIDS IN 19 HOST GALAXIES OF TYPE Ia SUPERNOVAE AND NGC 4258 WITH THEHUBBLE SPACE TELESCOPE

2016 ◽  
Vol 830 (1) ◽  
pp. 10 ◽  
Author(s):  
Samantha L. Hoffmann ◽  
Lucas M. Macri ◽  
Adam G. Riess ◽  
Wenlong Yuan ◽  
Stefano Casertano ◽  
...  
Keyword(s):  
Type Ia Supernovae ◽  
Host Galaxies ◽  
Optical Identification ◽  
Space Telescope ◽  
Type Ia ◽  
Ia Supernovae

scholarly journals A problem with the analysis of type Ia supernovae

2017 ◽  
Vol 26 (1) ◽  
Author(s):  
David F. Crawford
Keyword(s):  
Rest Frame ◽  
Time Dilation ◽  
Light Curves ◽  
Type Ia Supernovae ◽  
Standard Analysis ◽  
Static Universe ◽  
Direct Measurements ◽  
Type Ia ◽  
Absolute Magnitudes ◽  
Ia Supernovae

AbstractType Ia supernovae have light curves that have widths and magnitudes that can be used for testing cosmologies and they provide one of the few direct measurements of time dilation. It is shown that the standard analysis that calibrates the light curve against a rest-frame average (such as SALT2) removes all the cosmological information from the calibrated light curves. Consequently type Ia supernovae calibrated with these methods cannot be used to investigate cosmology. The major evidence that supports the hypothesis of a static universe is that the measurements of the widths of the rawlight curves of type Ia supernovae do not show any time dilation. The intrinsicwavelength dependence shown by the SALT2 calibration templates is also consistent with no time dilation. Using a static cosmological model the peak absolute magnitudes of raw type Ia supernovae observations are also independent of redshift. These results support the hypothesis of a static universe.

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