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441. UV-Optical light curves of the SNIa iPTF14bdn
ID:
ivo://CDS.VizieR/J/ApJ/813/30
Title:
UV-Optical light curves of the SNIa iPTF14bdn
Short Name:
J/ApJ/813/30
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present ultraviolet (UV) and optical photometry and spectra of the 1999aa-like supernova (SN) iPTF14bdn. The UV data were observed using the Swift Ultraviolet/Optical Telescope (UVOT) and constitute the first UV spectral series of a 1999aa-like SN. From the photometry, we measure {Delta}m_15_(B)=0.84+/-0.05mag and blue UV colors at epochs earlier than -5 days. The spectra show that the early-time blue colors are the result of less absorption between 2800-3200{AA} than is present in normal SNe Ia. Using model spectra fits of the data at -10 and +10days, we identify the origin of this spectral feature to be a temperature effect in which doubly ionized iron group elements create an opacity "window". We determine that the detection of high temperatures and large quantities of iron group elements at early epochs imply the mixing of a high Ni mass into the outer layers of the SN ejecta. We also identify the source of the I-band secondary maximum in iPTF14bdn to be the decay of FeIII to FeII, as is seen in normal SNe Ia.
442. UV/optical/NIR photometry for Type Ibn SNe
ID:
ivo://CDS.VizieR/J/MNRAS/449/1921
Title:
UV/optical/NIR photometry for Type Ibn SNe
Short Name:
J/MNRAS/449/1921
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present ultraviolet, optical and near-infrared data of the Type Ibn supernovae (SNe) 2010al and 2011hw. SN 2010al reaches an absolute magnitude at peak of M_R_=-18.86+/-0.21. Its early light curve shows similarities with normal SNe Ib, with a rise to maximum slower than most SNe Ibn. The spectra are dominated by a blue continuum at early stages, with narrow P-Cygni HeI lines indicating the presence of a slow-moving, He-rich circumstellar medium. At later epochs, the spectra well match those of the prototypical SN Ibn 2006jc, although the broader lines suggest that a significant amount of He was still present in the stellar envelope at the time of the explosion. SN 2011hw is somewhat different. It was discovered after the first maximum, but the light curve shows a double peak. The absolute magnitude at discovery is similar to that of the second peak (M_R_=-18.59+/-0.25), and slightly fainter than the average of SNe Ibn. Though the spectra of SN 2011hw are similar to those of SN 2006jc, coronal lines and narrow Balmer lines are clearly detected. This indicates substantial interaction of the SN ejecta with He-rich, but not H-free, circumstellar material. The spectra of SN 2011hw suggest that it is a transitional SN Ibn/IIn event similar to SN 2005la. While for SN 2010al the spectrophotometric evolution favours a H-deprived Wolf-Rayet progenitor (of WN-type), we agree with the conclusion of Smith et al. that the precursor of SN 2011hw was likely in transition from a luminous blue variable to an early Wolf-Rayet (Ofpe/WN_9_) stage.
443. UV-Opt light curves of the type Ic SN 2018gep
ID:
ivo://CDS.VizieR/J/ApJ/887/169
Title:
UV-Opt light curves of the type Ic SN 2018gep
Short Name:
J/ApJ/887/169
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present detailed observations of ZTF18abukavn (SN2018gep), discovered in high-cadence data from the Zwicky Transient Facility as a rapidly rising (1.4+/-0.1mag/hr) and luminous (M_g,peak_=-20mag) transient. It is spectroscopically classified as a broad-lined stripped-envelope supernova (Ic-BL SN). The high peak luminosity (L_bol>~3x10^44^erg/s), the short rise time (t_rise_=3days in g band), and the blue colors at peak (g-r~-0.4) all resemble the high-redshift Ic-BL iPTF16asu, as well as several other unclassified fast transients. The early discovery of SN2018gep (within an hour of shock breakout) enabled an intensive spectroscopic campaign, including the highest-temperature (T_eff_>~40000K) spectra of a stripped-envelope SN. A retrospective search revealed luminous (M_g_~M_r_~-14mag) emission in the days to weeks before explosion, the first definitive detection of precursor emission for a Ic-BL. We find a limit on the isotropic gamma-ray energy release E_{gamma,iso}_<4.9x10^48^erg, a limit on X-ray emission L_X_<10^40^erg/s, and a limit on radio emission {nu}L_{nu}_<~10^37^erg/s. Taken together, we find that the early (<10days) data are best explained by shock breakout in a massive shell of dense circumstellar material (0.02M_{sun}_) at large radii (3x10^14^cm) that was ejected in eruptive pre-explosion mass-loss episodes. The late-time (>10days) light curve requires an additional energy source, which could be the radioactive decay of Ni-56.
444. UVOT light curves of supernovae
ID:
ivo://CDS.VizieR/J/AJ/137/4517
Title:
UVOT light curves of supernovae
Short Name:
J/AJ/137/4517
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present ultraviolet (UV) observations of supernovae (SNe) obtained with the UltraViolet/Optical Telescope (UVOT) on board the Swift spacecraft. This is the largest sample of UV light curves from any single instrument and covers all major SN types and most subtypes.
445. UVOT photometry of Super-Chandrasekhar mass SNe Ia
ID:
ivo://CDS.VizieR/J/ApJ/787/29
Title:
UVOT photometry of Super-Chandrasekhar mass SNe Ia
Short Name:
J/ApJ/787/29
Date:
21 Oct 2021
Publisher:
CDS
Description:
Among Type Ia supernovae (SNe Ia), a class of overluminous objects exist whose ejecta mass is inferred to be larger than the canonical Chandrasekhar mass. We present and discuss the UV/optical photometric light curves, colors, absolute magnitudes, and spectra of three candidate Super-Chandrasekhar mass SNe - 2009dc, 2011aa, and 2012dn - observed with the Swift Ultraviolet/Optical Telescope. The light curves are at the broad end for SNe Ia, with the light curves of SN 2011aa being among the broadest ever observed. We find all three to have very blue colors which may provide a means of excluding these overluminous SNe from cosmological analysis, though there is some overlap with the bluest of "normal" SNe Ia. All three are overluminous in their UV absolute magnitudes compared to normal and broad SNe Ia, but SNe 2011aa and 2012dn are not optically overluminous compared to normal SNe Ia. The integrated luminosity curves of SNe 2011aa and 2012dn in the UVOT range (1600-6000 {AA}) are only half as bright as SN 2009dc, implying a smaller ^56^Ni yield. While it is not enough to strongly affect the bolometric flux, the early time mid-UV flux makes a significant contribution at early times. The strong spectral features in the mid-UV spectra of SNe 2009dc and 2012dn suggest a higher temperature and lower opacity to be the cause of the UV excess rather than a hot, smooth blackbody from shock interaction. Further work is needed to determine the ejecta and ^56^Ni masses of SNe 2011aa and 2012dn and to fully explain their high UV luminosities.
446. UVOT, ZTF gri LCs and spectra of the SN Ia 2019yvq
ID:
ivo://CDS.VizieR/J/ApJ/898/56
Title:
UVOT, ZTF gri LCs and spectra of the SN Ia 2019yvq
Short Name:
J/ApJ/898/56
Date:
16 Mar 2022 00:53:53
Publisher:
CDS
Description:
Early observations of Type Ia supernovae (SNe Ia) provide essential clues for understanding the progenitor system that gave rise to the terminal thermonuclear explosion. We present exquisite observations of SN 2019yvq, the second observed SN Ia, after iPTF 14atg, to display an early flash of emission in the ultraviolet (UV) and optical. Our analysis finds that SN 2019yvq was unusual, even when ignoring the initial flash, in that it was moderately underluminous for an SN Ia (M_g_~-18.5mag at peak) yet featured very high absorption velocities (v~15000km/s for SiII{lambda}6355 at peak). We find that many of the observational features of SN 2019yvq, aside from the flash, can be explained if the explosive yield of radioactive 56Ni is relatively low (we measure M_56Ni_=0.31+/-0.05M_{sun}_) and it and other iron-group elements are concentrated in the innermost layers of the ejecta. To explain both the UV/optical flash and peak properties of SN 2019yvq we consider four different models: interaction between the SN ejecta and a nondegenerate companion, extended clumps of ^56^Ni in the outer ejecta, a double-detonation explosion, and the violent merger of two white dwarfs. Each of these models has shortcomings when compared to the observations; it is clear additional tuning is required to better match SN 2019yvq. In closing, we predict that the nebular spectra of SN 2019yvq will feature either H or He emission, if the ejecta collided with a companion, strong [CaII] emission, if it was a double detonation, or narrow [OI] emission, if it was due to a violent merger.
447. UV to NIR light curves of type Ia SN 2017erp
ID:
ivo://CDS.VizieR/J/ApJ/877/152
Title:
UV to NIR light curves of type Ia SN 2017erp
Short Name:
J/ApJ/877/152
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present space-based ultraviolet/optical photometry and spectroscopy with the Swift Ultra-Violet/Optical Telescope and Hubble Space Telescope (HST), respectively, along with ground-based optical photometry and spectroscopy and near-infrared spectroscopy of supernova SN 2017erp. The optical light curves and spectra are consistent with a normal SN Ia. Compared to previous photometric samples in the near-ultraviolet (NUV), SN 2017erp has UV colors that are redder than NUV-blue SNe Ia corrected to similar optical colors. The chromatic difference between SNe 2011fe and 2017erp is dominated by the intrinsic differences in the UV rather than the expected dust reddening. This chromatic difference is similar to the SALT2 color law, derived from rest-frame ultraviolet photometry of higher redshift SNe Ia. Differentiating between intrinsic UV diversity and dust reddening can have important consequences for determining cosmological distances with rest-frame ultraviolet photometry. This ultraviolet spectroscopic series is the first from HST of a normal, albeit reddened, NUV-red SN Ia and is important for analyzing SNe Ia with intrinsically redder NUV colors. We 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{AA} implying a factor of ~10 higher metallicity in the upper layers of SN 2017erp 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.
448. UV to NIR obs. of SN 2019ehk
ID:
ivo://CDS.VizieR/J/ApJ/898/166
Title:
UV to NIR obs. of SN 2019ehk
Short Name:
J/ApJ/898/166
Date:
21 Mar 2022 09:18:33
Publisher:
CDS
Description:
We present panchromatic observations and modeling of the Calcium-rich supernova (SN) 2019ehk in the star-forming galaxy M100 (d~16.2Mpc) starting 10hr after explosion and continuing for ~300days. SN 2019ehk shows a double-peaked optical light curve peaking at t=3 and 15days. The first peak is coincident with luminous, rapidly decaying Swift-XRT-discovered X-ray emission (L_x_~10^41^erg/s at 3days; Lx{propto}t^-3^), and a Shane/Kast spectral detection of narrow H{alpha} and HeII emission lines (v~500km/s) originating from pre-existent circumstellar material (CSM). We attribute this phenomenology to radiation from shock interaction with extended, dense material surrounding the progenitor star at r<10^15^cm and the resulting cooling emission. We calculate a total CSM mass of ~7x10^-3^M_{sun}_ (M_He_/M_H_~6) with particle density n~10^9^cm^-3^. Radio observations indicate a significantly lower density n<10^4^cm^-3^ at larger radii r>(0.1-1)x10^17^cm. The photometric and spectroscopic properties during the second light-curve peak are consistent with those of Ca-rich transients (rise-time of t_r_=13.4!+/-0.210days and a peak B-band magnitude of M_B_=-15.1+/-0.200mag). We find that SN 2019ehk synthesized (3.1+/-0.11)x10^-2^M_{sun}_ of ^56^Ni and ejected M_ej_=(0.72+/-0.040)M_{sun}_ total with a kinetic energy E_k_=(1.8+/-0.10)x10^50^erg. Finally, deep HST pre-explosion imaging at the SN site constrains the parameter space of viable stellar progenitors to massive stars in the lowest mass bin (~10M_{sun}_) in binaries that lost most of their He envelope or white dwarfs (WDs). The explosion and environment properties of SN 2019ehk further restrict the potential WD progenitor systems to low-mass hybrid HeCO WD+CO WD binaries.
449. UV to visible-light observations of SN 2018fif
ID:
ivo://CDS.VizieR/J/ApJ/902/6
Title:
UV to visible-light observations of SN 2018fif
Short Name:
J/ApJ/902/6
Date:
25 Feb 2022 11:02:29
Publisher:
CDS
Description:
High-cadence transient surveys are able to capture supernovae closer to their first light than ever before. Applying analytical models to such early emission, we can constrain the progenitor stars' properties. In this paper, we present observations of SN 2018fif (ZTF18abokyfk). The supernova was discovered close to first light and monitored by the Zwicky Transient Facility (ZTF) and the Neil Gehrels Swift Observatory. Early spectroscopic observations suggest that the progenitor of SN 2018fif was surrounded by relatively small amounts of circumstellar material compared to all previous cases. This particularity, coupled with the high-cadence multiple-band coverage, makes it a good candidate to investigate using shock-cooling models. We employ the SOPRANOS code, an implementation of the model by Sapir & Waxman and its extension to early times by Morag et al. Compared with previous implementations, SOPRANOS has the advantage of including a careful account of the limited temporal validity domain of the shock-cooling model as well as allowing usage of the entirety of the early UV data. We find that the progenitor of SN 2018fif was a large red supergiant with a radius of R=744.0_-128.0_^+183.0^R_{sun}_ and an ejected mass of M_ej_=9.3_-5.8_^+0.4^M_{sun}_. Our model also gives information on the explosion epoch, the progenitor's inner structure, the shock velocity, and the extinction. The distribution of radii is double- peaked, with smaller radii corresponding to lower values of the extinction, earlier recombination times, and a better match to the early UV data. If these correlations persist in future objects, denser spectroscopic monitoring constraining the time of recombination, as well as accurate UV observations (e.g., with ULTRASAT), will help break the extinction/radius degeneracy and independently determine both.
450. Variations in supernova yields
ID:
ivo://CDS.VizieR/J/ApJ/664/1033
Title:
Variations in supernova yields
Short Name:
J/ApJ/664/1033
Date:
21 Oct 2021
Publisher:
CDS
Description:
Theoretical nucleosynthetic yields from supernovae are sensitive to both the details of the progenitor star and the explosion calculation. We attempt to comprehensively identify the sources of uncertainties in these yields. In this paper we concentrate on the variations in yields from a single progenitor arising from common 1D methods of approximating a supernova explosion. Subsequent papers will examine 3D effects in the explosion and the progenitor, and trends in mass and composition. For the 1D explosions we find that both elemental and isotopic yields for Si and heavier elements are a sensitive function of explosion energy. Also, piston-driven and thermal bomb-type explosions have different yields for the same explosion energy. Yields derived from 1D explosions are nonunique.