- ID:
- ivo://CDS.VizieR/J/ApJ/881/87
- Title:
- 9 epochs spectroscopy of type I supernova SN 201iet
- Short Name:
- J/ApJ/881/87
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- We present optical photometry and spectroscopy of SN2016iet (=Gaia16bvd=PS17brq), an unprecedented Type I supernova (SNI) at z=0.0676 with no obvious analog in the existing literature. SN2016iet exhibits a peculiar light curve, with two roughly equal brightness peaks (~-19mag) separated by about 100 days, and a subsequent slow decline by about 5mag in 650 rest-frame days. The spectra are dominated by strong emission lines of calcium and oxygen, with a width of only 3400km/s, superposed on a strong blue continuum in the first year. There is no clear evidence for hydrogen or helium associated with the SN at any phase. The nebular spectra exhibit a ratio of L_CaII_/L_OI_~4, much larger than for core-collapse SNe and TypeI superluminous SNe. We model the light curves with several potential energy sources: radioactive decay, a central engine, and ejecta-circumstellar medium (CSM) interaction. Regardless of the model, the inferred progenitor mass near the end of its life (i.e., the CO core mass) is >~55M{sun} and potentially up to 120M{sun}, clearly placing the event in the regime of pulsational pair instability supernovae (PPISNe) or pair instability supernovae (PISNe). The models of CSM interaction provide the most consistent explanation for the light curves and spectra, and require a CSM mass of ~35M{sun} ejected in the final decade before explosion. We further find that SN2016iet is located at an unusually large projected offset (16.5kpc, 4.3 effective radii) from its low-metallicity dwarf host galaxy (Z~0.1Z{sun}, L~0.02L*, M~108.5M{sun}), supporting the interpretation of a PPISN/PISN explosion. In our final spectrum at a phase of about 770 rest-frame days we detect weak and narrow H{alpha} emission at the location of the SN, corresponding to a star formation rate of ~3x10^-4^M{sun}/yr, which is likely due to a dim underlying galaxy host or an HII region. Despite the overall consistency of the SN and its unusual environment with PPISNe and PISNe, we find that the inferred properties of SN2016iet challenge existing models of such events.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/507/85
- Title:
- ESO/VLT 3rd year type Ia supernova data set
- Short Name:
- J/A+A/507/85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 139 spectra of 124 Type Ia supernovae (SNe Ia) that were observed at the ESO/VLT during the first three years of the Canada-France-Hawai Telescope (CFHT) supernova legacy survey (SNLS). This homogeneous data set is used to test for redshift evolution of SN Ia spectra, and will be used in the SNLS 3rd year cosmological analyses. Spectra have been reduced and extracted with a dedicated pipeline that uses photometric information from deep CFHT legacy survey (CFHT-LS) reference images to trace, at sub-pixel accuracy, the position of the supernova on the spectrogram as a function of wavelength. It also separates the supernova and its host light in ~60% of cases. The identification of the supernova candidates is performed using a spectrophotometric SN Ia model.
- ID:
- ivo://CDS.VizieR/J/AJ/137/3731
- Title:
- ESSENCE high-redshift supernova
- Short Name:
- J/AJ/137/3731
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of spectroscopic observations from the ESSENCE high-redshift supernova (SN) survey during its first four years of operation. This sample includes spectra of all SNe Ia whose light curves were presented by Miknaitis et al. (2007, Cat. J/ApJ/666/674) and used in the cosmological analyses of Davis et al. (2007ApJ...666..716D) and Wood-Vasey et al. (2007ApJ...666..694W). The sample represents 273hr of spectroscopic observations with 6.5-10m class telescopes of objects detected and selected for spectroscopy by the ESSENCE team. We present 184 spectra of 156 objects. Combining this sample with that of Matheson et al. (2008, Cat. J/AJ/135/1598), we have a total sample of 329 spectra of 274 objects. From this, we are able to spectroscopically classify 118 Type Ia SNe.
- ID:
- ivo://CDS.VizieR/J/ApJ/666/674
- Title:
- ESSENCE supernova survey
- Short Name:
- J/ApJ/666/674
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the implementation and optimization of the ESSENCE supernova survey, which we have undertaken to measure the dark energy equation-of-state parameter, w=P/({rho}c^2^). We present a method for optimizing the survey exposure times and cadence to maximize our sensitivity to w for a given fixed amount of telescope time. For our survey on the CTIO 4m telescope, measuring the luminosity distances and redshifts for supernovae at modest redshifts (z~0.5+/-0.2) is optimal for determining w. We describe the data analysis pipeline based on using reliable and robust image subtraction to find supernovae automatically and in nearly real time.
- ID:
- ivo://CDS.VizieR/J/ApJS/224/3
- Title:
- ESSENCE 6yr spectroscopic follow-up
- Short Name:
- J/ApJS/224/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Equation of State: Supernovae trace Cosmic Expansion (ESSENCE) survey discovered 213 Type Ia supernovae at redshifts 0.1<z<0.81 between 2002 and 2008. We present their R- and I-band photometry, measured from images obtained using the MOSAIC II camera at the CTIO Blanco, along with rapid-response spectroscopy for each object. We use our spectroscopic follow-up observations to determine an accurate, quantitative classification, and precise redshift. Through an extensive calibration program we have improved the precision of the CTIO Blanco natural photometric system. We use several empirical metrics to measure our internal photometric consistency and our absolute calibration of the survey. We assess the effect of various potential sources of systematic bias on our measured fluxes, and estimate the dominant term in the systematic error budget from the photometric calibration on our absolute fluxes is ~1%.
- ID:
- ivo://CDS.VizieR/J/ApJ/608/405
- Title:
- Explosive yields of massive star (Z=0-Z_{sun}_)
- Short Name:
- J/ApJ/608/405
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new and homogeneous set of explosive yields for masses 13, 15, 20, 25, 30, and 35M_{sun}_ and metallicities Z=0, 10^-6^, 10^-4^, 10^-3^, 6x10^-3^, and 2x10^-2^. A wide network extending up to Mo has been used in all computations. We show that at low metallicities (Z<=10^-4^), the final yields do not depend significantly on the initial chemical composition of the models, so a scaled solar distribution may be safely assumed at all metallicities. Moreover, no elements above Zn are produced by any mass in the grid up to a metallicity ~10-3. These yields are available for any choice of the mass cut on request.
- ID:
- ivo://CDS.VizieR/J/MNRAS/328/1181
- Title:
- Extragalactic supernovae
- Short Name:
- J/MNRAS/328/1181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to investigate the influence of environment on supernova (SN) production, we have performed a statistical investigation of the SNe discovered in isolated galaxies, in pairs and in groups of galaxies. 22 SNe in 18 isolated galaxies, 48 SNe in 40 galaxy members of 37 pairs and 211 SNe in 170 galaxy members of 116 groups have been selected and studied.
- ID:
- ivo://CDS.VizieR/J/other/Sci/340.45
- Title:
- Fast shocks around SN 1006
- Short Name:
- J/other/Sci/340.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Supernova remnants are among the most spectacular examples of astrophysical pistons in our cosmic neighborhood. The gas expelled by the supernova explosion is launched with velocities ~1000 kilometers per second into the ambient, tenuous interstellar medium, producing shocks that excite hydrogen lines. We have used an optical integral-field spectrograph to obtain high-resolution spatial-spectral maps that allow us to study in detail the shocks in the northwestern rim of supernova 1006. The two-component H{alpha} line is detected at 133 sky locations. Variations in the broad line widths and the broad-to-narrow line intensity ratios across tens of atomic mean free paths suggest the presence of suprathermal protons, the potential seed particles for generating high-energy cosmic rays.
- ID:
- ivo://CDS.VizieR/J/A+A/554/A27
- Title:
- 2011fe spectrophotometric time series
- Short Name:
- J/A+A/554/A27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 32 epochs of optical (3300-9700{AA}) spectrophotometric observations of the nearby quintessential "normal" type Ia supernova (SN Ia) SN 2011fe in the galaxy M101, extending from -15 to +97d with respect to B-band maximum, obtained by the Nearby Supernova Factory collaboration. SN 2011fe is the closest ({mu}=29.04) and brightest (Bmax=9.94mag) SN Ia observed since the advent of modern large scale programs for the intensive periodic followup of supernovae. Both synthetic light curve measurements and spectral feature analysis attest to the normality of SN 2011fe. There is very little evidence for reddening in its host galaxy. The homogeneous calibration, intensive time sampling, and high signal-to-noise ratio of the data set make it unique. Thus it is ideal for studying the physics of SN Ia explosions in detail, and for furthering the use of SNe Ia as standardizable candles for cosmology.
- ID:
- ivo://CDS.VizieR/J/MNRAS/438/L101
- Title:
- First month on SN 2013ej
- Short Name:
- J/MNRAS/438/L101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present early photometric and spectroscopic observations of SN 2013ej, a bright Type IIP supernova (SN) in M74. SN 2013ej is one of the closest SNe ever discovered. The available archive images and the early discovery help to constrain the nature of its progenitor. The earliest detection of this explosion was on 2013 July 24.125 ut and our spectroscopic monitoring with the FLOYDS spectrographs began on July 27.7 ut, continuing almost daily for two weeks. Daily optical photometric monitoring was achieved with the 1m telescopes of the Las Cumbres Observatory Global Telescope (LCOGT) network, and was complemented by UV data from Swift and near-infrared spectra from Public ESO Spectroscopic Survey of Transient Objects and Infrared Telescope Facility. The data from our monitoring campaign show that SN 2013ej experienced a 10d rise before entering into a well-defined plateau phase. This unusually long rise time for a Type IIP has been seen previously in SN 2006bp and SN 2009bw. A relatively rare strong absorption blueward of H{alpha} is present since our earliest spectrum. We identify this feature as SiII, rather than high-velocity H{alpha} as sometimes reported in the literature.
