J/ApJ/924/35 Optical spectra of type Ia SN 2015bq (Li+, 2022)
SN 2015bq: a luminous type Ia supernova with early flux excess.
Li L., Zhang J., Dai B., Li W., Wang X., Zhai Q., Bai J.
<Astrophys. J., 924, 35 (2022)>
=2022ApJ...924...35L 2022ApJ...924...35L
ADC_Keywords: Supernovae; Spectra, optical
Keywords: Supernovae ; Type Ia supernovae
Abstract:
We present optical and ultraviolet (UV) observations of a luminous
type Ia supernova (SN Ia) SN 2015bq characterized by early flux
excess. This SN reaches a B-band absolute magnitude at
MB=-19.68±0.41mag and a peak bolometric luminosity at
L=(1.75±0.37)x1043erg/s, with a relatively small post-maximum
decline rate [Δm15(B)=0.82±0.05mag]. The flux excess
observed in the light curves of SN 2015bq a few days after the
explosion, especially seen in the UV bands, might be due to the
radioactive decay of 56Ni mixed into the surface. The radiation from
the decay of the surface 56Ni heats the outer layer of this SN. It
produces blue U-B color followed by monotonically reddening in the
early phase, dominated iron-group lines, and weak intermediate-mass
element absorption features in the early spectra. The scenario of
enhanced 56Ni in the surface is consistent with a large amount of
56Ni (M56Ni=0.97±0.20M☉) synthesized during the explosion.
The properties of SN 2015bq are found to locate between SN 1991T and
SN 1999aa, suggesting the latter two subclasses of SNe Ia may have a
common origin.
Description:
Thanks to the supernova program (LiONS, Lijiang One hour per Night for
Supernova observation) of the Lijiang 2.4m telescope (LJT), we can
monitor the transient SN 2015bq frequently in both photometric and
spectroscopic modes. The observing campaign at LJT spanned from
t~-12days to t~+106days relative to the B-band maximum (JD2457084.62).
Twenty-three low-resolution spectra collected by the LJT, spanning
from t=-10days to t=+83 days, are listed in Table A4 and presented in
Figure 2. Furthermore, one spectrum was also obtained with the Beijing
Faint Object Spectrograph and Camera (BFOSC) mounted on the Xing-Long
2.16m telescope (XLT) at Xing-long Observatory of the National
Astronomical Observatories (NAOC).
Objects:
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RA (ICRS) DE Designation(s)
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12 35 06.37 +31 14 35.4 SN 2015bq = iPTF 15ku
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea4.dat 82 24 Spectroscopic observation journal of SN 2015bq
sp/* . 24 Individual spectra in ASCII format
(Data behind Figure 2)
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See also:
J/AJ/131/527 : UBVRI light curves of 44 type Ia supernovae (Jha+, 2006)
J/ApJ/645/488 : SN type Ia luminosities (Wang+, 2006)
J/ApJ/700/331 : Light curves of type Ia supernovae (CfA3) (Hicken+, 2009)
J/ApJ/699/L139 : Spectral parameters of SNe Ia (Wang+, 2009)
J/AJ/143/126 : Spectroscopy of 462 nearby Type Ia supernovae (Blondin+, 2012)
J/ApJ/753/22 : Swift/UVOT observations of SN 2011fe (Brown+, 2012)
J/A+A/554/A27 : 2011fe spectrophotometric time series (Pereira+, 2013)
J/AJ/148/1 : Optical and ultraviolet photometry of SN 2012fr (Zhang+, 2014)
J/ApJ/813/30 : UV-Optical light curves of the SNIa iPTF14bdn (Smitka+, 2015)
J/ApJS/220/20 : Si and Ca high-velocity features in SNe Ia (Zhao+, 2015)
J/AJ/151/125 : Optical and UV photometry of SN 2013dy (Zhai+, 2016)
J/MNRAS/491/2902 : Sub-Chandrasekhar progenitors for Type Ia SNe (Flors+, 2020)
J/A+A/634/A37 : TURTLS Light curves of 56Ni distributions (Magee+, 2020)
Byte-by-byte Description of file: tablea4.dat
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Bytes Format Units Label Explanations
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1- 11 A11 "Y/M/D" Date Date of observation (UT)
13- 20 F8.2 d MJD [57071.9/57164.7] Modified Julian Date
22- 27 F6.2 d Epoch [-12.19/80.55] Epoch; referring to the peak
of B band on March 03.12 2015, JD2457084.62
29- 30 I2 0.1nm/pix Res [18/49] Resolution in Å/pixel
32- 35 I4 0.1nm lam1 [3500/3800] Wavelength upper range in Å
36 A1 --- --- [-]
37- 40 I4 0.1nm lam2 [8700/9100] Wavelength lower range in Å
42- 45 I4 s Exp [1415/3000] Exposure time
47- 50 F4.2 --- AirMass [1/1.44] Air mass
52- 60 A9 --- Tel Telescope / Instrument (Lijiang 2.4m
telescope (LJT) or Xing-Long 2.16m telescope
(XLT))
62- 82 A21 --- FileName Name of the ASCII file in subdirectory "sp";
column added by CDS
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Byte-by-byte Description of file: sp/*
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Bytes Format Units Label Explanations
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1- 16 F16.11 0.1nm lambda [3488.8/9146.7] Wavelength, Angstroms
18- 38 E21.6 cW/m2/nm S [-7.9e-16/3.3e-15] Flux density,
in erg/s/cm2/Å units
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 02-Aug-2023