Monte Carlo radiative transfer for the nebular phase of Type Ia supernovae

ABSTRACT We extend the range of validity of the artis 3D radiative transfer code up to hundreds of days after explosion, when Type Ia supernovae (SNe Ia) are in their nebular phase. To achieve this, we add a non-local thermodynamic equilibrium population and ionization solver, a new multifrequency radiation field model, and a new atomic data set with forbidden transitions. We treat collisions with non-thermal leptons resulting from nuclear decays to account for their contribution to excitation, ionization, and heating. We validate our method with a variety of tests including comparing our synthetic nebular spectra for the well-known one-dimensional W7 model with the results of other studies. As an illustrative application of the code, we present synthetic nebular spectra for the detonation of a sub-Chandrasekhar white dwarf (WD) in which the possible effects of gravitational settling of 22Ne prior to explosion have been explored. Specifically, we compare synthetic nebular spectra for a 1.06 M⊙ WD model obtained when 5.5 Gyr of very efficient settling is assumed to a similar model without settling. We find that this degree of 22Ne settling has only a modest effect on the resulting nebular spectra due to increased 58Ni abundance. Due to the high ionization in sub-Chandrasekhar models, the nebular [Ni ii] emission remains negligible, while the [Ni iii] line strengths are increased and the overall ionization balance is slightly lowered in the model with 22Ne settling. In common with previous studies of sub-Chandrasekhar models at nebular epochs, these models overproduce [Fe iii] emission relative to [Fe ii] in comparison to observations of normal SNe Ia.

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Understanding nebular spectra of Type Ia supernovae

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa640 ◽

2020 ◽

Vol 494 (2) ◽

pp. 2221-2235 ◽

Cited By ~ 2

Author(s):

Kevin D Wilk ◽

D John Hillier ◽

Luc Dessart

Keyword(s):

Radiative Transfer ◽

Local Thermodynamic Equilibrium ◽

Diagnostic Feature ◽

Type Ia Supernovae ◽

Thermal Heating ◽

One Dimensional ◽

Type Ia ◽

Natural Mechanism ◽

Non Local ◽

Ia Supernovae

ABSTRACT In this study, we present one-dimensional, non-local-thermodynamic-equilibrium, radiative transfer simulations (using cmfgen) in which we introduce micro-clumping at nebular times into two Type Ia supernova ejecta models. We use one sub-Chandrasekhar (sub-MCh) ejecta model with 1.04 M⊙ and one Chandrasekhar (MCh) ejecta model with 1.40 M⊙. We introduce clumping factors f = 0.33, 0.25, and 0.10, which are constant throughout the ejecta, and compare results to the unclumped f = 1.0 case. We find that clumping is a natural mechanism to reduce the ionization of the ejecta, reducing emission from [Fe iii], [Ar iii], and [S iii] by a factor of a few. For decreasing values of the clumping factor f, the [Ca ii] λλ7291,7324 doublet became a dominant cooling line for our MCh model but remained weak in our sub-MCh model. Strong [Ca ii] λλ7291,7324 indicates non-thermal heating in that region and may constrain explosion modelling. Due to the low abundance of stable nickel, our sub-MCh model never showed the [Ni ii] 1.939-μm diagnostic feature for all clumping values.

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VARIABLE CHAPLYGIN GAS: CONSTRAINTS FROM CMBR ANDSNe Ia

International Journal of Modern Physics D ◽

10.1142/s0218271806008644 ◽

2006 ◽

Vol 15 (07) ◽

pp. 1089-1098 ◽

Cited By ~ 15

Author(s):

GEETANJALI SETHI ◽

SUSHIL K. SINGH ◽

PRANAV KUMAR ◽

DEEPAK JAIN ◽

ABHA DEV

Keyword(s):

Equation Of State ◽

Positive Function ◽

Chaplygin Gas ◽

Scale Factor ◽

Type Ia Supernovae ◽

Data Set ◽

Cosmological Scale ◽

Type Ia ◽

Ia Supernovae

We constrain the parameters of the variable Chaplygin gas model, using the location of peaks of the CMBR spectrum and the SNe Ia "gold" data set. The equation of state of the model is P = -A(a)/ρ, where A(a) = A0a-nis a positive function of the cosmological scale factor a, A0and n> being constants. The variable Chaplygin gas interpolates from the dust-dominated era to the quintessence dominated era. The model is found to be compatible with current type Ia supernovae data and the location of the first peak if the values of Ωmand n lie in the interval [0.017, 0.117] and [-1.3, 2.6], respectively.

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Polarization as a probe of dusty environments around Type Ia supernovae: radiative transfer models for SN 2012dn

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/sty538 ◽

2018 ◽

Vol 476 (4) ◽

pp. 4806-4813 ◽

Cited By ~ 2

Author(s):

Takashi Nagao ◽

Keiichi Maeda ◽

Masayuki Yamanaka

Keyword(s):

Radiative Transfer ◽

Type Ia Supernovae ◽

Radiative Transfer Models ◽

Type Ia ◽

Ia Supernovae ◽

Transfer Models

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Lick Observatory Supernova Search follow-up program: photometry data release of 93 Type Ia supernovae

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2742 ◽

2019 ◽

Vol 490 (3) ◽

pp. 3882-3907 ◽

Cited By ~ 10

Author(s):

Benjamin E Stahl ◽

WeiKang Zheng ◽

Thomas de Jaeger ◽

Alexei V Filippenko ◽

Andrew Bigley ◽

...

Keyword(s):

Light Curves ◽

Type Ia Supernovae ◽

Data Set ◽

Future Studies ◽

Processing Pipeline ◽

Type Ia ◽

Template Fitting ◽

Ia Supernovae ◽

Distance Indicators

ABSTRACT We present BVRI and unfiltered light curves of 93 Type Ia supernovae (SNe Ia) from the Lick Observatory Supernova Search (LOSS) follow-up program conducted between 2005 and 2018. Our sample consists of 78 spectroscopically normal SNe Ia, with the remainder divided between distinct subclasses (3 SN 1991bg-like, 3 SN 1991T-like, 4 SNe Iax, 2 peculiar, and 3 super-Chandrasekhar events), and has a median redshift of 0.0192. The SNe in our sample have a median coverage of 16 photometric epochs at a cadence of 5.4 d, and the median first observed epoch is ∼4.6 d before maximum B-band light. We describe how the SNe in our sample are discovered, observed, and processed, and we compare the results from our newly developed automated photometry pipeline to those from the previous processing pipeline used by LOSS. After investigating potential biases, we derive a final systematic uncertainty of 0.03 mag in BVRI for our data set. We perform an analysis of our light curves with particular focus on using template fitting to measure the parameters that are useful in standardizing SNe Ia as distance indicators. All of the data are available to the community, and we encourage future studies to incorporate our light curves in their analyses.

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Optical Spectroscopy of Type Ia Supernovae

International Astronomical Union Colloquium ◽

10.1017/s0252921100009131 ◽

2005 ◽

Vol 192 ◽

pp. 161-165

Author(s):

Thomas Matheson

Keyword(s):

Spectroscopic Data ◽

Comprehensive Analysis ◽

Light Curves ◽

Type Ia Supernovae ◽

Data Set ◽

Type Ia ◽

Spectroscopic Database ◽

Similarities And Differences ◽

Ia Supernovae ◽

Homogeneous Data

SummaryThe supernova (SN) group at the Harvard-Smithsonian Center for Astrophysics has been using the facilities of the F. L. Whipple Observatory to gather optical photometric and spectroscopic data on nearby supernovae for several years. The collection of spectra of Type Ia SNe is now large enough to allow a comprehensive analysis. I will present preliminary results from a study of a subsample of the CfA Type Ia spectroscopic database, with over 200 spectra of 31 Type Ia SNe. The SNe selected all have well-calibrated light curves and cover a wide scope of luminosity classes. The epochs of observation range from fourteen days before maximum to fifty days past maximum. All of the spectra were obtained with the same instrument on the same telescope, and were reduced using the same techniques. With such a large, homogeneous data set, the spectroscopic similarities and differences among Type Ia SNe become readily apparent.

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Measuring the Hubble constant with Type Ia supernovae as near-infrared standard candles

Astronomy and Astrophysics ◽

10.1051/0004-6361/201731501 ◽

2018 ◽

Vol 609 ◽

pp. A72 ◽

Cited By ~ 75

Author(s):

Suhail Dhawan ◽

Saurabh W. Jha ◽

Bruno Leibundgut

Keyword(s):

Light Curve ◽

Near Infrared ◽

Sample Selection ◽

Hubble Constant ◽

Type Ia Supernovae ◽

Curve Shape ◽

Data Set ◽

Optical Photometry ◽

Type Ia ◽

Ia Supernovae

The most precise local measurements of H0 rely on observations of Type Ia supernovae (SNe Ia) coupled with Cepheid distances to SN Ia host galaxies. Recent results have shown tension comparing H0 to the value inferred from CMB observations assuming ΛCDM, making it important to check for potential systematic uncertainties in either approach. To date, precise local H0 measurements have used SN Ia distances based on optical photometry, with corrections for light curve shape and colour. Here, we analyse SNe Ia as standard candles in the near-infrared (NIR), where luminosity variations in the supernovae and extinction by dust are both reduced relative to the optical. From a combined fit to 9 nearby calibrator SNe with host Cepheid distances from Riess et al. (2016) and 27 SNe in the Hubble flow, we estimate the absolute peak J magnitude MJ = −18.524 ± 0.041 mag and H0 = 72.8 ± 1.6 (statistical) ±2.7 (systematic) km s-1 Mpc-1. The 2.2% statistical uncertainty demonstrates that the NIR provides a compelling avenue to measuring SN Ia distances, and for our sample the intrinsic (unmodeled) peak J magnitude scatter is just ~0.10 mag, even without light curve shape or colour corrections. Our results do not vary significantly with different sample selection criteria, though photometric calibration in the NIR may be a dominant systematic uncertainty. Our findings suggest that tension in the competing H0 distance ladders is likely not a result of supernova systematics that could be expected to vary between optical and NIR wavelengths, like dust extinction. We anticipate further improvements in H0 with a larger calibrator sample of SNe Ia with Cepheid distances, more Hubble flow SNe Ia with NIR light curves, and better use of the full NIR photometric data set beyond simply the peak J-band magnitude.

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Study of some parameters of modified Chaplygin gas in Galileon gravity theory from observational perspective

Canadian Journal of Physics ◽

10.1139/cjp-2014-0287 ◽

2014 ◽

Vol 92 (12) ◽

pp. 1667-1675 ◽

Cited By ~ 2

Author(s):

Chayan Ranjit ◽

Prabir Rudra ◽

Ujjal Debnath

Keyword(s):

Chaplygin Gas ◽

Cosmic Acceleration ◽

Joint Analysis ◽

Type Ia Supernovae ◽

Distance Modulus ◽

Modified Chaplygin Gas ◽

Data Set ◽

Type Ia ◽

Ia Supernovae ◽

Best Fit

We have assumed the Friedmann–Robertson–Walker model of the universe in Galileon gravity, which is filled with dark matter and modified Chaplygin gas (MCG) type dark energy. We present the Hubble parameter in terms of some unknown parameters and observational parameters with the redshift z. Some cosmological parameters are reconstructed and plots are generated to study the nature of the model and its viability. It is seen that the model is perfectly consistent with the present cosmic acceleration. From observed Hubble data (OHD) set or Stern data set of 12 points, we have obtained the bounds of the arbitrary parameters (A, B) and (A, C) by minimizing the χ2 test. Next because of joint analysis of OHD + baryonic acoustic oscillation (BAO) and OHD+BAO+CMB observations, we have also obtained the best fit values and the bounds of the parameters (A, B) and (A, C) by fixing some other parameters. The best-fit values and bounds of the parameters are obtained with 66%, 90%, and 99% confidence levels for OHD, OHD+BAO, and OHD+BAO+CMB joint analysis. Next we have also taken type Ia supernovae data set (union2 data set with 557 data points). The distance modulus μ(z) against redshift z for our theoretical MCG model in Galileon gravity have been tested for the best fit values of the parameters and the observed type Ia supernovae union2 data sample and from this, we have concluded that our model is in agreement with the union2 sample data.

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