J/ApJ/900/73 LRS2 spectra of SN 2019neq (Konyves-Toth+, 2020)
Comparative spectral analysis of the superluminous supernova 2019neq.
Konyves-Toth R., Thomas B.P., Vinko J., Wheeler J.C.
<Astrophys. J., 900, 73 (2020)>
=2020ApJ...900...73K 2020ApJ...900...73K
ADC_Keywords: Supernovae; Spectra, optical
Keywords: Supernovae ; Core-collapse supernovae ; Ejecta ; Atomic spectroscopy ;
Chemical abundances ; Astrochemistry
Abstract:
We present a spectroscopic analysis of the recently discovered
fast-evolving Type I superluminous supernova (SLSN-I) SN 2019neq (at
redshift z=0.1059). We compare it to the well-studied slowly evolving
SLSN-I SN 2010kd (z=0.101). Our main goal is to search for
spectroscopic differences between the two groups of SLSNe-I.
Differences in the spectra may reveal different ejecta compositions
and explosion mechanisms. Our investigation concentrates on optical
spectra observed with the 10m Hobby-Eberly Telescope Low Resolution
Spectrograph-2 at McDonald Observatory during the photospheric phase.
We apply the SYN++ code to model the spectra of SN 2019neq taken at
-4days, +5days, and +29days from maximum light. We examine the
chemical evolution and ejecta composition of the SLSN by identifying
the elements and ionization states in its spectra. We find that a
spectral model consisting of OIII, CoIII, and SiIV gives a SYN++ fit
that is comparable to the typical SLSN-I spectral model consisting of
OII, and conclude that the true identification of those lines, at
least in the case of SN 2019neq, is ambiguous. Based on modeling the
entire optical spectrum, we classify SN 2019neq as a fast-evolving
SLSN-I having a photospheric velocity gradient of dv/dt∼375km/s/day,
which is among the highest velocity gradients observed for an SLSN-I.
Inferring the velocity gradient from the proposed FeIIλ5169
feature alone would result in dv/dt∼100km/s/day, which is still within
the observed range of fast-evolving SLSNe-I. In addition, we derive
the number density of relevant ionization states for a variety of
identified elements at the epoch of the three observations. Finally,
we give constraints on the lower limit of the ejecta mass and find
that both SLSNe have an ejecta mass at least one order of magnitude
higher than normal SNe Ia, while the fast-evolving SN 2019neq has an
ejecta mass a factor of two lower than the slowly evolving SN 2010kd.
These mass estimates suggest the existence of a possible correlation
between the evolution timescale and the ejected mass of SLSNe-I.
Description:
SN 2019neq was discovered (RAJ2000=17:54:26.736,DEJ2000=+47:15:40.56)
by the Zwicky Transient Facility (ZTF) public survey on 2019 August 10
at 05:25:45 UT.
A series of spectral observations were obtained by the SED Machine
between 2019 August 11 and 22. A 2x900s spectrum was obtained by SPRAT
on the Liverpool Telescope on 2019 August 27.
Here we present three optical spectra (3640≤λ≤10000Å) of
SN 2019neq (first reported by Thomas+ 2019ATel13184....1T 2019ATel13184....1T), taken with
the Low Resolution Spectrograph-2 (LRS2) mounted on the 10m
Hobby-Eberly Telescope (HET) at McDonald Observatory in Texas. We
obtained these spectra on 2019 September 1, 11 and 2019 October 6/8.
Each of these observations was carried out in both the blue (LRS2-B:
3640-6970Å) and red (LRS2-R: 6440-11000Å) arms of LRS2, with
1800s integration times per arm for the first two observations. The
third observation was split between two nights due to non-ideal
weather conditions, and exposed for 2100s.
Objects:
-------------------------------------------------------
RA (ICRS) DE Designation(s)
-------------------------------------------------------
17 54 26.74 +47 15 40.6 SN 2019neq = ZTF19abpbopt
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig1.dat 27 19546 The observed spectra of SN 2019neq
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See also:
J/A+A/538/A120 : A unified supernova catalogue (Lennarz+, 2012)
J/MNRAS/451/1973 : Type Ia supernovae igh-velocity features (Silverman+, 2015)
J/MNRAS/458/84 : Host galaxies of Superluminous Supernovae (Angus+, 2016)
J/ApJ/832/108 : Spectral properties of Type Ic & Ic-bl SNe (Modjaz+, 2016)
J/ApJ/830/13 : Host-galaxy NUV-NIR data of superluminous SNe (Perley+, 2016)
J/ApJ/845/85 : Absorption velocities for super-luminous SNe Ic (Liu+, 2017)
J/ApJ/860/100 : LCs of 26 hydrogen-poor superluminous SNe (De Cia+, 2018)
J/ApJ/852/81 : PS1 superluminous SNe LCs + classif. spectra (Lunnan+, 2018)
Byte-by-byte Description of file: fig1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Epoch [-4/29] Rest-frame observation epoch (1)
5- 10 A6 --- Inst Instrument used ("LRS2", "LRS2-B" or
"LRS2-R")
12- 20 F9.3 0.1nm lambda [3640/10280] Wavelength; in Angstrom units
22- 27 F6.3 10-15cW/m2/nm Flux [-0.02/9] Observed flux;
in 10-15erg/s/cm2/Å units
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Note (1): Days from maximum as follows:
-4 = 2019 September 01 04:48:06 UT
+5 = 2019 September 11 04:01:28 UT
+29 = 2019 October 06 02:35:56 UT (blue)
+29 = 2019 October 08 02:37:06 (red)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 16-Dec-2021