arXiv subjects

Maximilian Stritzinger

Publications and source records attributed to Maximilian Stritzinger.

80 records · Page 5Linked to original sources

arXiv2009

The He-rich core-collapse supernova 2007Y: Observations from X-ray to Radio Wavelengths

A detailed study spanning approximately a year has been conducted on the Type Ib supernova 2007Y. Imaging was obtained from X-ray to radio wavelengths, and a comprehensive set of multi-band (w2m2w1u'g'r'i'UBVYJHKs) light curves and optical spectroscopy is presented. A virtually complete bolometric light curve is derived, from which we infer a (56)Ni-mass of 0.06 M_sun. The early spectrum strongly resembles SN 2005bf and exhibits high-velocity features of CaII and H_alpha; during late epochs the spectrum shows evidence of a ejecta-wind interaction. Nebular emission lines have similar widths and exhibit profiles that indicate a lack of major asymmetry in the ejecta. Late phase spectra are modeled with a non-LTE code, from which we find (56)Ni, O and total-ejecta masses (excluding He) to be 0.06, 0.2 and 0.42 M_sun, respectively, below 4,500 km/s. The (56)Ni mass confirms results obtained from the bolometric light curve. The oxygen abundance suggests the progenitor was most likely a ~3.3 M_sun He core star that evolved from a zero-age-main-sequence mass of 10-13 M_sun. The explosion energy is determined to be ~10^50 erg, and the mass-loss rate of the progenitor is constrained from X-ray and radio observations to be <~10^-6 M_sun/yr. SN 2007Y is among the least energetic normal Type Ib supernovae ever studied.

astro-ph.HE↗

arXiv2008

First-Year Spectroscopy for the SDSS-II Supernova Survey

This paper presents spectroscopy of supernovae discovered in the first season of the Sloan Digital Sky Survey-II Supernova Survey. This program searches for and measures multi-band light curves of supernovae in the redshift range z = 0.05 - 0.4, complementing existing surveys at lower and higher redshifts. Our goal is to better characterize the supernova population, with a particular focus on SNe Ia, improving their utility as cosmological distance indicators and as probes of dark energy. Our supernova spectroscopy program features rapid-response observations using telescopes of a range of apertures, and provides confirmation of the supernova and host-galaxy types as well as precise redshifts. We describe here the target identification and prioritization, data reduction, redshift measurement, and classification of 129 SNe Ia, 16 spectroscopically probable SNe Ia, 7 SNe Ib/c, and 11 SNe II from the first season. We also describe our efforts to measure and remove the substantial host galaxy contamination existing in the majority of our SN spectra.

astro-ph↗

arXiv2007

Late-time emission of type Ia supernovae: optical and near-infrared observations of SN 2001el

We present optical and near-infrared light curves of SN 2001el from 310 to 445 days past maximum light, obtained with the Very Large Telescope. The late-time optical (UBVRI) light curves decay in a nearly linear fashion with decay time scales of 1.43\pm0.14, 1.43\pm0.06, 1.48\pm0.06, 1.45\pm0.07, and 1.03\pm0.07 magnitudes (per hundred days) in the U, B, V, R and I bands, respectively. In contrast, in the near-infrared (JHKs) bands the time evolution of the flux appears to be nearly constant at these epochs. We measure decline rates (per hundred days) of 0.19\pm0.10 and 0.17\pm0.11 magnitudes in the J and H bands, respectively. We construct a UVOIR light curve, and find that the late-time luminosity has a decay time scale nearly consistent with complete depostion of positron kinetic energy. The late-time light curves of the normal type Ia SN 2001el demonstrate the increased importance of the near-infrared contribution. This was previously observed in the peculiar SN 2000cx, and the results for SN 2001el thus ensure that the conclusions previously based on a single peculiar event are applicable to normal type Ia supernovae. The measured late-time UVOIR decline rate suggests that a majority of the positrons are trapped within the ejecta. This results does not favor the predictions of a weak and/or radially combed magnetic field configuration.

astro-ph↗

arXiv2006

Consistent estimates of (56)Ni yields for type Ia supernovae

We present (56)Ni mass estimates for seventeen well-observed type Ia supernovae determined by two independent methods. Estimates of the (56)Ni mass for each type Ia supernova are determined from (1) modeling of the late-time nebular spectrum and (2) through the combination of the peak bolometric luminosity with Arnett's rule. The attractiveness of this approach is that the comparison of estimated (56)Ni masses circumvents errors associated with the uncertainty in the adopted values of reddening and distance. We demonstrate that these two methods provide consistent estimates of the amount of (56)Ni synthesized. We also find a strong correlation between the derived (56)Ni mass and the absolute B-band magnitude (M(B)). Spectral synthesis can be used as a diagnostic to study the explosion mechanism. By obtaining more nebular spectra the Nif--M(B) correlation can be calibrated and can be used to investigate any potential systematic effects this relationship may have on the determination of cosmological parameters, and provide a new way to estimate extra-galactic distances of nearby type Ia supernovae.

astro-ph↗

arXiv2005

Constraints on the Progenitor Systems of Type Ia Supernovae

UVOIR bolometric light curves provide valuable insight into the nature of type Ia supernovae. We present an analysis of sixteen well-observed SNe Ia. Constraints are placed on several global parameters concerning the progenitor system, explosion mechanism and subsequent radiation transport. By fitting a radioactive decay energy deposition function to the quasi-exponential phase (50 to 100 days after maximum light), it is found that the ejected mass varies by at least a factor of two. This result suggests that a sub-Chandrasekhar mass model could be responsible for the progenitor system of some type Ia supernovae. We find that the range in the amount of synthesized (56)Ni indicates a significant variation in the burning mechanism. In order to explain a factor of ten range in the observed bolometric luminosity more detailed modeling of the explosion mechanism is required.

astro-ph↗

arXiv2005

An Atlas of Spectrophotometric Landolt Standard Stars

We present CCD observations of 102 Landolt standard stars obtained with the R-C spectrograph on the CTIO 1.5 m telescope. Using stellar atmosphere models we have extended the flux points to our six spectrophotometric secondary standards, in both the blue and the red, allowing us to produce flux-calibrated spectra that span a wavelength range from 3050 Åto 1.1 \micron. Mean differences between UBVRI spectrophotometry computed using Bessell's standard passbands and Landolt's published photometry is found to be 1% or less. Observers in both hemispheres will find these spectra useful for flux-calibrating spectra and through the use of accurately constructed instrumental passbands be able to compute accurate corrections to bring instrumental magnitudes to any desired standard photometric system (S-corrections). In addition, by combining empirical and modeled spectra of the Sun, Sirius and Vega, we calculate and compare synthetic photometry to observed photometry taken from the literature for these three stars.

astro-ph↗

arXiv2003

Optical and Infrared Photometry of the Nearby Type Ia Supernovae 1999ee, 2000bh, 2000ca, and 2001ba

We present near infrared photometry of the Type Ia supernova 1999ee; also, optical and infrared photometry of the Type Ia SNe 2000bh, 2000ca, and 2001ba. For SNe 1999ee and 2000bh we present the first-ever SN photometry at 1.035 microns (the Y-band). We present K-corrections which transform the infrared photometry in the observer's frame to the supernova rest frame. Using our infrared K-corrections and stretch factors derived from optical photometry, we construct JHK templates which can be used to determine the apparent magnitudes at maximum if one has some data in the window -12 to +10 d with respect to T(B_max). Following up previous work on the uniformity of V minus IR loci of Type Ia supernovae of mid-range decline rates, we present unreddened loci for slow decliners. We also discuss evidence for a continuous change of color at a given epoch as a function of decline rate.

astro-ph↗

arXiv2002

Evidence for Core Collapse in the Type Ib/c SN 1999ex

We present optical and infrared spectra of SN 1999ex that reveal a clear example of an intermediate Type Ib/c case. This suggests a continuous spectroscopic sequence between Type Ib and Type Ic supernovae. We report UBVRIz photometric observations of SN 1999ex that started only one day after explosion, which permitted us to witness an elusive transient cooling phase that lasted 4 days. The initial cooling and subsequent radioactive heating produced a dip in the lightcurve which is consistent with explosion models involving core collapse of evolved massive helium stars, and inconsistent with lightcurves resulting from the thermonuclear runaway of compact white dwarfs.

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