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Start Over Subject infrared photometry Subject spectroscopy Subject supernovae Subject wide-band photometry
1. AT 2018hso light curves and spectra
ID:
ivo://CDS.VizieR/J/A+A/632/L6
Title:
AT 2018hso light curves and spectra
Short Name:
J/A+A/632/L6
Date:
21 Oct 2021
Publisher:
CDS
Description:
The absolute magnitudes of luminous red novae (LRNe) are intermediate between those of novae and supernovae (SNe), and show a relatively homogeneous spectro-photometric evolution. Although they were thought to derive from core instabilities in single stars, there is growing support for the idea that they are triggered by binary interaction that possibly ends with the merging of the two stars. AT 2018hso is a new transient showing transitional properties between those of LRNe and the class of intermediate-luminosity red transients (ILRTs) similar to SN 2008S. Through the detailed analysis of the observed parameters, our study support that it actually belongs to the LRN class and was likely produced by the coalescence of two massive stars. We obtained ten months of optical and near-infrared photometric monitoring, and 11 epochs of low-resolution optical spectroscopy of AT 2018hso. We compared its observed properties with those of other ILRTs and LRNe. We also inspected the archival Hubble Space Telescope (HST) images obtained about 15 years ago to constrain the progenitor properties. The light curves of AT 2018hso show a first sharp peak (reddening-corrected M_r_=13.93mag), followed by a broader and shallower second peak that resembles a plateau in the optical bands. The spectra dramatically change with time. Early-time spectra show prominent Balmer emission lines and a weak [CaII] doublet, which is usually observed in ILRTs. However, the strong decrease in the continuum temperature, the appearance of narrow metal absorption lines, the great change in the H{alpha} strength and profile, and the emergence of molecular bands support an LRN classification. The possible detection of a M_I_~8mag source at the position of AT 2018hso in HST archive images is consistent with expectations for a pre-merger massive binary, similar to the precursor of the 2015 LRN in M101. We provide reasonable arguments to support an LRN classification for AT 2018hso. This study reveals growing heterogeneity in the observables of LRNe than has been thought previously, which is a challenge for distinguishing between LRNe and ILRTs. This suggests that the entire evolution of gap transients needs to be monitored to avoid misclassifications.
2. BVRI, spectra & IR obs. of type II-P SN2017eaw
ID:
ivo://CDS.VizieR/J/ApJ/875/136
Title:
BVRI, spectra & IR obs. of type II-P SN2017eaw
Short Name:
J/ApJ/875/136
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present extensive optical photometric and spectroscopic observations, from 4 to 482 days after explosion, of the Type II-plateau (II-P) supernova (SN) 2017eaw in NGC 6946. SN 2017eaw is a normal SN II-P intermediate in properties between, for example, SN 1999em and SN 2012aw and the more luminous SN 2004et, also in NGC6946. We have determined that the extinction to SN 2017eaw is primarily due to the Galactic foreground and that the SN site metallicity is likely subsolar. We have also independently confirmed a tip-of-the-red-giant-branch (TRGB) distance to NGC 6946 of 7.73+/-0.78Mpc. The distances to the SN that we have also estimated via both the standardized candle method and expanding photosphere method corroborate the TRGB distance. We confirm the SN progenitor identity in pre-explosion archival Hubble Space Telescope (HST) and Spitzer Space Telescope images, via imaging of the SN through our HST Target of Opportunity program. Detailed modeling of the progenitor's spectral energy distribution indicates that the star was a dusty, luminous red supergiant consistent with an initial mass of ~15M_{sun}_.
3. CSP-II: sp. obs. of the 03fg-like SN Ia LSQ14fmg
ID:
ivo://CDS.VizieR/J/ApJ/900/140
Title:
CSP-II: sp. obs. of the 03fg-like SN Ia LSQ14fmg
Short Name:
J/ApJ/900/140
Date:
02 Feb 2022 11:26:50
Publisher:
CDS
Description:
The Type Ia supernova (SN Ia) LSQ14fmg exhibits exaggerated properties that may help to reveal the origin of the "super-Chandrasekhar" (or 03fg-like) group. The optical spectrum is typical of a 03fg-like SNIa, but the light curves are unlike those of any SNe Ia observed. The light curves of LSQ14fmg rise extremely slowly. At -23 rest-frame days relative to B-band maximum, LSQ14fmg is already brighter than M_V_=-19mag before host extinction correction. The observed color curves show a flat evolution from the earliest observation to approximately 1 week after maximum. The near-infrared light curves peak brighter than -20.5mag in the J and H bands, far more luminous than any 03fg-like SNe Ia with near-infrared observations. At 1 month past maximum, the optical light curves decline rapidly. The early, slow rise and flat color evolution are interpreted to result from an additional excess flux from a power source other than the radioactive decay of the synthesized 56Ni. The excess flux matches the interaction with a typical superwind of an asymptotic giant branch (AGB) star in density structure, mass-loss rate, and duration. The rapid decline starting at around 1 month past B-band maximum may be an indication of rapid cooling by active carbon monoxide (CO) formation, which requires a low-temperature and high-density environment. These peculiarities point to an AGB progenitor near the end of its evolution and the core degenerate scenario as the likely explosion mechanism for LSQ14fmg.
4. Follow-up observations of SNIa ASASSN-14lp
ID:
ivo://CDS.VizieR/J/ApJ/826/144
Title:
Follow-up observations of SNIa ASASSN-14lp
Short Name:
J/ApJ/826/144
Date:
21 Oct 2021
Publisher:
CDS
Description:
On 2014 December 9.61, the All-sky Automated Survey for SuperNovae (ASAS-SN or "Assassin") discovered ASASSN-14lp just ~2 days after first light using a global array of 14cm diameter telescopes. ASASSN-14lp went on to become a bright supernova (V=11.94mag), second only to SN 2014J for the year. We present prediscovery photometry (with a detection less than a day after first light) and ultraviolet through near-infrared photometric and spectroscopic data covering the rise and fall of ASASSN-14lp for more than 100 days. We find that ASASSN-14lp had a broad light curve ({Delta}m_15_(B)=0.80+/-0.05), a B-band maximum at 2457015.82+/-0.03, a rise time of 16.94_-0.10_^+0.11^days, and moderate host-galaxy extinction (E(B-V)_host_=0.33+/-0.06). Using ASASSN-14lp, we derive a distance modulus for NGC 4666 of {mu}=30.8+/-0.2, corresponding to a distance of 14.7+/-1.5Mpc. However, adding ASASSN-14lp to the calibrating sample of Type Ia supernovae still requires an independent distance to the host galaxy. Finally, using our early-time photometric and spectroscopic observations, we rule out red giant secondaries and, assuming a favorable viewing angle and explosion time, any nondegenerate companion larger than 0.34R_{sun}_.
5. Follow-up of candidate counterparts of S190814bv
ID:
ivo://CDS.VizieR/J/ApJ/890/131
Title:
Follow-up of candidate counterparts of S190814bv
Short Name:
J/ApJ/890/131
Date:
21 Oct 2021
Publisher:
CDS
Description:
On 2019 August 14, the Advanced LIGO and Virgo interferometers detected the high-significance gravitational wave (GW) signal S190814bv. The GW data indicated that the event resulted from a neutron star-black hole (NSBH) merger, or potentially a low-mass binary BH merger. Due to the low false-alarm rate and the precise localization (23deg^2^ at 90%), S190814bv presented the community with the best opportunity yet to directly observe an optical/near-infrared counterpart to an NSBH merger. To search for potential counterparts, the GROWTH Collaboration performed real-time image subtraction on six nights of public Dark Energy Camera images acquired in the 3 weeks following the merger, covering >98% of the localization probability. Using a worldwide network of follow-up facilities, we systematically undertook spectroscopy and imaging of optical counterpart candidates. Combining these data with a photometric redshift catalog, we ruled out each candidate as the counterpart to S190814bv and placed deep, uniform limits on the optical emission associated with S190814bv. For the nearest consistent GW distance, radiative transfer simulations of NSBH mergers constrain the ejecta mass of S190814bv to be M_ej_<0.04M_{sun}_ at polar viewing angles, or M_ej_<0.03M_{sun}_ if the opacity is {kappa}<2cm^2^g^-1^. Assuming a tidal deformability for the NS at the high end of the range compatible with GW170817 results, our limits would constrain the BH spin component aligned with the orbital momentum to be {chi}<0.7 for mass ratios Q<6, with weaker constraints for more compact NSs.
6. Follow-up optical observations of the SNIc SN2014L
ID:
ivo://CDS.VizieR/J/ApJ/863/109
Title:
Follow-up optical observations of the SNIc SN2014L
Short Name:
J/ApJ/863/109
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present optical spectroscopic and photometric observations of the nearby type Ic supernova (SN Ic) SN 2014L. This SN was discovered by the Tsinghua-NAOC Transient Survey (TNTS) in the nearby type-Sc spiral galaxy M99 (NGC 4254). Fitting to the early-time light curve indicates that SN 2014L was detected at only a few hours after the shock breakout, and it reached a peak brightness of M_V_=-17.73+/-0.28mag (L=[2.06+/-0.50]x10^42^erg/s) approximately 13 days later. SN 2014L shows a close resemblance to SN 2007gr in the photometric evolution, while it shows stronger absorption features of intermediate-mass elements (especially CaII) in the early-time spectra. Based on simple modeling of the observed light curves, we derived the mass of synthesized ^56^Ni as M_Ni_=0.075+/-0.025M_{sun}_, and the mass and total energy of the ejecta as M_ej_=1.00+/-0.20M_{sun}_ and E_ej_=1.45+/-0.25 foe, respectively. Given these typical explosion parameters, the early detection, and the extensive observations, we suggest that SN 2014L could be a template sample for the investigation of SNe Ic.
7. Photometric observations of SN PTF11iqb
ID:
ivo://CDS.VizieR/J/MNRAS/449/1876
Title:
Photometric observations of SN PTF11iqb
Short Name:
J/MNRAS/449/1876
Date:
21 Oct 2021
Publisher:
CDS
Description:
The supernova (SN) PTF11iqb was initially classified as a Type IIn event caught very early after explosion. It showed narrow Wolf-Rayet (WR) spectral features on day 2 (as in SN 1998S and SN 2013cu), but the narrow emission weakened quickly and the spectrum morphed to resemble Types II-L and II-P. At late times, H{alpha} exhibited a complex, multipeaked profile reminiscent of SN 1998S. In terms of spectroscopic evolution, we find that PTF11iqb was a near twin of SN 1998S, although with somewhat weaker interaction with circumstellar material (CSM) at early times, and stronger interaction at late times. We interpret the spectral changes as caused by early interaction with asymmetric CSM that is quickly (by day 20) enveloped by the expanding SN ejecta photosphere, but then revealed again after the end of the plateau when the photosphere recedes. The light curve can be matched with a simple model for CSM interaction (with a mass-loss rate of roughly 10^-4^ M_{sun}_/yr) added to the light curve of a normal SN II-P. The underlying plateau requires a progenitor with an extended hydrogen envelope like a red supergiant at the moment of explosion, consistent with the slow wind speed (<80 km/s) inferred from narrow H{alpha} emission. The cool supergiant progenitor is significant because PTF11iqb showed WR features in its early spectrum - meaning that the presence of such WR features does not necessarily indicate a WR-like progenitor. Overall, PTF11iqb bridges SNe IIn with weaker pre-SN mass-loss seen in SNe II-L and II-P, implying a continuum between these types.
8. Photometry and spectroscopy of SN 2010jl
ID:
ivo://CDS.VizieR/J/AJ/144/131
Title:
Photometry and spectroscopy of SN 2010jl
Short Name:
J/AJ/144/131
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present extensive optical observations of a Type IIn supernova (SN IIn) 2010jl for the first 1.5years after its discovery. The UBVRI light curves demonstrated an interesting two-stage evolution during the nebular phase, which almost flatten out after about 90days from the optical maximum. SN 2010jl has one of the highest intrinsic H{alpha} luminosities ever recorded for an SN IIn, especially at late phase, suggesting a strong interaction of SN ejecta with the dense circumstellar material (CSM) ejected by the progenitor. This is also indicated by the remarkably strong Balmer lines persisting in the optical spectra. One interesting spectral evolution about SN 2010jl is the appearance of asymmetry of the Balmer lines. These lines can be well decomposed into a narrow component and an intermediate-width component. The intermediate-width component showed a steady increase in both strength and blueshift with time until t~400days after maximum, but it became less blueshifted at t~500days, when the line profile appeared relatively symmetric again. Owing to the fact that a pure reddening effect will lead to a sudden decline of the light curves and a progressive blueshift of the spectral lines, we therefore propose that the asymmetric profiles of H lines seen in SN 2010jl are unlikely due to the extinction by newly formed dust inside the ejecta, contrary to the explanation by some early studies. Based on a simple CSM-interaction model, we speculate that the progenitor of SN 2010jl may suffer a gigantic mass loss (~30-50M_{sun}_) a few decades before explosion. Considering a slow-moving stellar wind (e.g.,~28km/s) inferred for the preexisting, dense CSM shell and the extremely high mass-loss rate (1-2M_{sun}_/yr), we suggest that the progenitor of SN 2010jl might have experienced a red supergiant stage and may explode finally as a post-red supergiant star with an initial mass above 30-40M_{sun}_.
9. 17 PS1 superluminous SNe LCs + classif. spectra
ID:
ivo://CDS.VizieR/J/ApJ/852/81
Title:
17 PS1 superluminous SNe LCs + classif. spectra
Short Name:
J/ApJ/852/81
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present light curves and classification spectra of 17 hydrogen-poor superluminous supernovae (SLSNe) from the Pan-STARRS1 Medium Deep Survey (PS1 MDS). Our sample contains all objects from the PS1 MDS sample with spectroscopic classification that are similar to either of the prototypes SN 2005ap or SN 2007bi, without an explicit limit on luminosity. With a redshift range 0.3<z<1.6, PS1 MDS is the first SLSN sample primarily probing the high-redshift population; our multifilter PS1 light curves probe the rest- frame UV emission, and hence the peak of the spectral energy distribution. We measure the temperature evolution and construct bolometric light curves, and find peak luminosities of (0.5-5)x10^44^erg/s and lower limits on the total radiated energies of (0.3-2)x10^51^erg. The light curve shapes are diverse, with both rise and decline times spanning a factor of ~5 and several examples of double-peaked light curves. When correcting for the flux-limited nature of our survey, we find a median peak luminosity at 4000{AA} of M_4000_=-21.1mag and a spread of {sigma}=0.7mag.
10. PTF 12dam & iPTF 13dcc follow-up
ID:
ivo://CDS.VizieR/J/ApJ/835/58
Title:
PTF 12dam & iPTF 13dcc follow-up
Short Name:
J/ApJ/835/58
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the light curves of the hydrogen-poor superluminous supernovae (SLSNe I) PTF 12dam and iPTF 13dcc, discovered by the (intermediate) Palomar Transient Factory. Both show excess emission at early times and a slowly declining light curve at late times. The early bump in PTF 12dam is very similar in duration (~10days) and brightness relative to the main peak (2-3mag fainter) compared to that observed in other SLSNe I. In contrast, the long-duration (>30days) early excess emission in iPTF 13dcc, whose brightness competes with that of the main peak, appears to be of a different nature. We construct bolometric light curves for both targets, and fit a variety of light-curve models to both the early bump and main peak in an attempt to understand the nature of these explosions. Even though the slope of the late-time decline in the light curves of both SLSNe is suggestively close to that expected from the radioactive decay of ^56^Ni and ^56^Co, the amount of nickel required to power the full light curves is too large considering the estimated ejecta mass. The magnetar model including an increasing escape fraction provides a reasonable description of the PTF 12dam observations. However, neither the basic nor the double-peaked magnetar model is capable of reproducing the light curve of iPTF 13dcc. A model combining a shock breakout in an extended envelope with late-time magnetar energy injection provides a reasonable fit to the iPTF 13dcc observations. Finally, we find that the light curves of both PTF 12dam and iPTF 13dcc can be adequately fit with the model involving interaction with the circumstellar medium.

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