J/A+A/643/A35 Light curves of 5 supernovae (Paraskeva+, 2020)
First systematic high-precision survey of bright supernovae.
I. Methodology for identifying early bumps.
Paraskeva E., Bonanos A.Z., Liakos A., Spetsieri Z.T., Maund J.R.
<Astron. Astrophys. 643, A35 (2020)>
=2020A&A...643A..35P 2020A&A...643A..35P (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Photometry ; Optical
Keywords: methods: data analysis - techniques: image processing -
supernovae: general - methods: observational - techniques: photometric
Abstract:
Rapid variability before and near the maximum brightness of supernovae
has the potential to provide a better understanding of nearly every
aspect of supernovae, from the physics of the explosion up to their
progenitors and the circumstellar environment. Thanks to
modern time-domain optical surveys, which are discovering supernovae
in the early stage of their evolution, we have the unique opportunity
to capture their intraday behavior before maximum. We present
high-cadence photometric monitoring (on the order of seconds-minutes)
of the optical light curves of three Type Ia and two Type II SNe over
several nights before and near maximum light, using the fast imagers
available on the 2.3m Aristarchos telescope at Helmos Observatory and
the 1.2m telescope at Kryoneri Observatory in Greece. We applied
differential aperture photometry techniques using optimal apertures
and we present reconstructed light curves after implementing a seeing
correction and the Trend Filtering Algorithm (TFA, Kovacs et al.
2005MNRAS.356..557K 2005MNRAS.356..557K). TFA yielded the best results, achieving a
typical precision between 0.01 and 0.04mag. We did not detect
significant bumps with amplitudes greater than 0.05mag in any of the
SNe targets in the VR-, R-, and I- bands light curves obtained. We
measured the intraday slope for each light curve, which ranges between
-0.37-0.36mag/d in broadband VR, -0.19-0.31mag/d in R band, and
-0.13-0.10mag/d in I band. We used SNe light curve fitting templates
for SN 2018gv, SN 2018hgc and SN 2018hhn to photometrically classify
the light curves and to calculate the time of maximum. We provide
values for the maximum of SN 2018zd after applying a low-order
polynomial fit and SN 2018hhn for the first time. We conclude that
optimal aperture photometry in combination with TFA provides the
highest-precision light curves for SNe that are relatively well
separated from the centers of their host galaxies. This work aims to
inspire the use of ground-based, high-cadence and high-precision
photometry to study SNe with the purpose of revealing clues and
properties of the explosion environment of both core-collapse and Type
Ia supernovae, the explosion mechanisms, binary star interaction and
progenitor channels. We suggest monitoring early supernovae light
curves in hotter (bluer) bands with a cadence of hours as a promising
way of investigating the post-explosion photometric behavior of the
progenitor stars.
Description:
We used the RISE2 instrument installed on the 2.3m f/8
Ritchey-Chretien Aristarchos telescope at Helmos Observatory to
observe SNe 2018hgc, 2018hhn and 2018hna. RISE2 is equipped with an
ANDOR DW485 camera with an E2V CCD47-20 back-illuminated CCD sensor,
which has a 1024x1024-pixel light sensitive region (pixel size
13.0x13.0um2) and is used for detecting transiting exoplanets. The
field of view of the instrument is 10'x10', providing a pixel scale of
0.60". The instrument uses a single broad filter, similar to the V+R
passband.
We used the wide-field, high-cadence camera system, installed on the
prime focus of the 1.2m Kryoneri telescope to observe SN 2018gv and
2018zd. The instrument consists of two Andor Zyla 5.5 cameras, each
with a 2560x2160 front-illuminated scientific CMOS (pixel size
0.06x0.06um2) resulting in a pixel scale of 0.4" and a 17"x14" field
of view. It provides the means to record a target simultaneously in
two different wavelength bands. A dichroic with a cutoff at 730nm splits
the light beam, sending each resulting beam to a different camera. The
cameras are equipped with R and Iband Johnson-Cousins filters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 77 7 Log of observations
18gv-i.dat 75 105 SN 2018gv I band light curves
18gv-r.dat 75 105 SN 2018gv R band light curves
18hgc-vr.dat 51 227 SN 2018hgc VR band light curves
18hhn-vr.dat 75 37 SN 2018hhn VR band light curves
18hna-vr.dat 51 120 SN 2018hna VR band light curves
18zd-i.dat 75 522 SN 2018zd I band light curves
18zd-r.dat 75 514 SN 2018zd R band light curves
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Supernova name
12- 13 I2 h RAh Right ascension (J2000)
15- 16 I2 min RAm Right ascension (J2000)
18- 22 F5.2 s RAs Right ascension (J2000)
24 A1 --- DE- Declination sign (J2000)
25- 26 I2 deg DEd Declination (J2000)
28- 29 I2 arcmin DEm Declination (J2000)
31- 35 F5.2 arcsec DEs Declination (J2000)
37- 42 A6 --- Type Type
44 A1 --- n_Type [ab] Note on Type (1)
46- 47 A2 --- Filter [R I VR] Filter
49- 52 I4 --- NFrame Total number of frames
54- 64 A11 --- Tel Telescope
66- 77 A12 --- FileName Name of the table with light curve data
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Note (1): Notes as follows:
a = Initially, it was spectroscopically classified as a Type IIn by
Zhang et al. (2018ATel11379....1Z 2018ATel11379....1Z).
b = Initially, it was classified as a normal Type II supernova. According to
Singh et al. (2019ApJ...882L..15S 2019ApJ...882L..15S), this SN is a 1987A-like event object.
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Byte-by-byte Description of file: 18*.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Band [V I VR] Band
4- 19 F16.8 d HJD1 ? Heliocentric Julian date, 1st part of the night
21- 26 F6.3 mag mag1 ? Magnitude, 1st part of the night, in Band
29- 44 F16.8 d HJD2 ? Heliocentric Julian date, 2nd part of the night
46- 51 F6.3 mag mag2 ? Magnitude, 2nd part of the night, in Band
53- 68 F16.8 d HJD3 ? Heliocentric Julian date (1)
70- 75 F6.3 mag mag3 ? Magnitude, 3rd part of the night, in Band (1)
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Note (1): Not for 18hgc-vr.dat and 18hna-vr.dat
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Acknowledgements:
Emmanouela Paraskeva, eparaskeva(at)noa.gr
(End) Patricia Vannier [CDS] 20-Jul-2020