J/ApJ/946/7 BVI light curves and sp. of Type Ia SN 2018aoz (Ni+, 2023)
The origin and evolution of the normal type Ia SN 2018aoz with infant-phase
reddening and excess emission.
Ni Y.Qi, Moon D.-S., Drout M.R., Polin A., Sand D.J., Gonzalez-Gaitan S.,
Kim S.C., Lee Y., Park H.S., Howell D.A., Nugent P.E., Piro A.L.,
Brown P.J., Galbany L., Burke J., Hiramatsu D., Hosseinzadeh G.,
Valenti S., Afsariardchi N., Andrews J.E., Antoniadis J., Beaton R.L.,
Bostroem K.A., Carlberg R.G., Cenko S.B., Cha S.-M., Dong Y., Gal-Yam A.,
Haislip J., Holoien T.W.-S., Johnson S.D., Kouprianov V., Lee Y.,
Matzner C.D., Morrell N., McCully C., Pignata G., Reichart D.E., Rich J.,
Ryder S.D., Smith N., Wyatt S., Yang S.
<Astrophys. J., 946, 7 (2023)>
=2023ApJ...946....7N 2023ApJ...946....7N
ADC_Keywords: Photometry, UBVRI; Supernovae; Spectra, optical
Keywords: Binary stars ; Supernovae ; Type Ia supernovae ; White dwarf stars ;
Transient sources ; Time domain astronomy
Abstract:
SN 2018aoz is a Type Ia SN with a B-band plateau and excess emission
in infant-phase light curves ≲1d after the first light, evidencing an
over-density of surface iron-peak elements as shown in our previous
study. Here, we advance the constraints on the nature and origin of
SN2018aoz based on its evolution until the nebular phase. Near-peak
spectroscopic features show that the SN is intermediate between two
subtypes of normal Type Ia: core normal and broad line. The excess
emission may be attributable to the radioactive decay of surface
iron-peak elements as well as the interaction of ejecta with either
the binary companion or a small torus of circumstellar material.
Nebular-phase limits on Hα and HeI favor a white dwarf
companion, consistent with the small companion size constrained by the
low early SN luminosity, while the absence of [OI] and HeI disfavors a
violent merger of the progenitor. Of the two main explosion mechanisms
proposed to explain the distribution of surface iron-peak elements in
SN 2018aoz, the asymmetric Chandrasekhar-mass explosion is less
consistent with the progenitor constraints and the observed blueshifts
of nebular-phase [FeII] and [NiII]. The helium-shell double-detonation
explosion is compatible with the observed lack of C spectral features,
but current 1D models are incompatible with the infant-phase excess
emission, Bmax--Vmax color, and weak strength of nebular-phase
[CaII]. Although the explosion processes of SN 2018aoz still need to
be more precisely understood, the same processes could produce a
significant fraction of Type Ia SNe that appear to be normal after ∼1d.
Description:
SN 2018aoz was identified by both the KMTNet Supernova Program (KSP)
and Distance Less Than 40 Mpc Survey (DLT40). The earliest detection
of the SN with a signal-to-noise ratio (S/N)>3 was made by KSP in the
B band at 00h54m on 2018 March 29 UT, or MJD 58206.0378.
The early observations of SN 2018aoz obtained ∼110 days since the
first light were presented in Paper I (Ni+ 2022NatAs...6..568N 2022NatAs...6..568N). Here,
we present additional KSP photometry continuing from >250d since the
first light, covering the nebular phase (Section 2.1), as well as new
nebular-phase spectroscopy of the SN (Section 2.2).
We used the three 1.6m telescopes of the Korea Microlensing Telescope
Network (KMTNet) in Chile, South Africa, and Australia to conduct
photometric observations of SN 2018aoz during its nebular phase, >200d
since the B-band maximum. Between 2018 December and 2019 June, we
conducted high-cadence monitoring of a 2°x2° field containing
the source, obtaining ∼500 images of the field with 60s exposure times
at a mean cadence of ∼9hr in each of the BVI bands.
We obtained four low-resolution nebular-phase optical spectra of
SN2018aoz at 259.4, 277.3, 296.4, and 382.5d since the B-band maximum
with a combination of the Gemini Multi-Object Spectrograph (GMOS) on
Gemini-South, the Low Resolution Imaging Spectrometer (LRIS) on Keck,
and the Low Dispersion Survey Spectrograph-3 (LDSS-3) on Magellan-Clay.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
11 51 01.91 -28 44 38.7 SN 2018aoz = DLT 18q
----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 26 1177 Nebular-phase magnitudes of SN 2018aoz
table2.dat 179 4 Nebular-phase spectroscopy of SN 2018aoz
sp/* . 7 Individual spectra in FITS and ASCII format
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See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-)
J/AJ/135/1598 : Optical spectroscopy of type Ia supernovae (Matheson+, 2008)
J/ApJ/699/L139 : Spectral parameters of SNe Ia (Wang+, 2009)
J/AJ/143/126 : Spectroscopy of nearby Type Ia supernovae (Blondin+, 2012)
J/ApJ/753/22 : Swift/UVOT observations of SN 2011fe (Brown+, 2012)
J/other/NewA/20.30 : BVRI light curves of 3 SN (Munari+, 2013)
J/A+A/554/A27 : 2011fe spectrophotometric time series (Pereira+, 2013)
J/other/Sci/340.170 : Classifications of 188 SNe Ia (Wang+, 2013)
J/ApJ/787/29 : UVOT phot. of Super-Chandrasekhar mass SNe Ia (Brown+, 2014)
J/MNRAS/444/3258 : Velocities and EW of PTF SNe Ia (Maguire+, 2014)
J/ApJ/821/57 : Photometry of the Type Ib/c SN2013ge (Drout+, 2016)
J/ApJ/836/232 : Swift-UVOT obs. analysis of 29 SNe Ia (Brown+, 2017)
J/A+A/604/L6 : EBLM J0555-57 photometry and RV (von Boetticher+, 2017)
J/ApJ/869/56 : Updated calib. of the CSP-I SNe Ia sample (Burns+, 2018)
J/ApJ/853/62 : Opt and NIR spectra and LCs of SN2016ija (Tartaglia+, 2018)
J/ApJ/881/22 : BVI phot. of TypeII SN KSP-SN-2016kf (Afsariardchi+, 2019)
J/ApJ/877/152 : UV to NIR light curves of type Ia SN 2017erp (Brown+, 2019)
J/ApJ/870/L1 : K2 obs. of type Ia supernova SN 2018oh (Dimitriadis+, 2019)
J/A+A/627/A174 : Early light curve of SN 2013gy (Holmbo+, 2019)
J/MNRAS/483/628 : SN Ia data using bolometric light curves (Scalzo+, 2019)
J/ApJ/870/13 : K2 LC alternative analysis of ASASSN-18bt (Shappee+, 2019)
J/ApJ/886/152 : ZTF early observations of Type Ia SNe. I. LCs (Yao+, 2019)
J/ApJ/902/48 : ZTF early obs. of type Ia supernovae. III. (Bulla+, 2020)
J/MNRAS/491/2902 : Sub-Chandrasekhar progenitors for Type Ia SNe (Flors+, 2020)
J/ApJ/898/56 : UVOT, ZTF gri LCs & sp. of the SN Ia 2019yvq (Miller+, 2020)
J/ApJ/902/47 : ZTF early obs. of type Ia SNe. II. Rise time (Miller+, 2020)
J/MNRAS/493/1044 : Nebular spectra of 111 Type Ia supernovae (Tucker+, 2020)
J/ApJ/922/186 : Keck/NIRES spectrum of type Ia SN 2020qxp (Hoeflich+, 2021)
J/ApJ/910/151 : KMTNet BVi photometry of SNIa KSP-OT-201509b (Moon+, 2021)
J/ApJ/914/50 : Opt. phot. and GMOS & NIRES sp. of SN2019yvq (Tucker+, 2021)
J/ApJ/925/L22 : KMTNet BVI LCs & spectroscopy of KSP-OT-201701a (Lee+, 2022)
J/ApJ/926/L25 : New LBT/MODS spectra of type Ia SN 2011fe (Tucker+, 2022)
http://www.wiserep.org/ : Weizmann Interactive Supernova Data Repository
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.5 d MJD [58471.68/58658] Modified Julian Date
13- 13 A1 --- Band [BVi] Photometric band used
15- 20 F6.3 mag mag [19.19/22.1] Apparent magnitude in Band (1)
22- 26 F5.3 mag e_mag [0.03/0.4] Uncertainty in mag
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Note (1): The BV-band magnitudes are in the Vega system, while the
i-band magnitudes are in the AB system.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 yr Date.Y Year of observation date (UT)
6- 8 A3 "month" Date.M Month of observation date (UT)
10- 14 F5.2 d Date.D Decimal day of observation date (UT)
16- 21 F6.1 d Phase [259.4/382.5] Observer frame days since the
B-band maximum light (MJD 58221.41)
23- 35 A13 --- Tel Telescope
37- 42 A6 --- Inst Instrument
44- 47 I4 --- R [860/2000] Resolution
49- 52 I4 0.1nm lam1 [3200/5000] Lower limit of wavelength in Å
53 A1 --- --- [-]
54- 58 I5 0.1nm lam2 [10000] Upper limit of wavelength in Å
60-118 A59 --- File1 Name of the spectra in subdirectory "sp"
in ASCII format; column added by CDS
120-179 A60 --- File2 Name of the spectra in subdirectory "sp"
in FITS format; column added by CDS
--------------------------------------------------------------------------------
Acknowledgements:
Yuan Qi Ni [chris.ni at mail.utoronto.ca]
WISeREP - https://www.wiserep.org
History:
From electronic version of the journal for the tables.
Spectra downloaded from WISeREP: http://www.wiserep.org/object/1084
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 14-Feb-2025