J/ApJ/789/104 SNe IIn observations and properties (Ofek+, 2014)
Precursors prior to type IIn supernova explosions are common: precursor rates,
properties, and correlations.
Ofek E.O., Sullivan M., Shaviv N.J., Steinbok A., Arcavi I., Gal-Yam A.,
Tal D., Kulkarni S.R., Nugent P.E., Ben-Ami S., Kasliwal M.M., Cenko S.B.,
Laher R., Surace J., Bloom J.S., Filippenko A.V., Silverman J.M., Yaron O.
<Astrophys. J., 789, 104 (2014)>
=2014ApJ...789..104O 2014ApJ...789..104O (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Photometry ; Magnitudes
Keywords: stars: mass-loss - supernovae: general - supernovae: individual:
SN 2010mc - PTF 10bjb - SN 2011ht - PTF 10weh - PTF 12cxj - SN 2009ip
Abstract:
There is a growing number of Type IIn supernovae (SNe) which present
an outburst prior to their presumably final explosion. These
precursors may affect the SN display, and are likely related to poorly
charted phenomena in the final stages of stellar evolution. By
coadding Palomar Transient Factory (PTF) images taken prior to the
explosion, here we present a search for precursors in a sample of 16
Type IIn SNe. We find five SNe IIn that likely have at least one
possible precursor event (PTF 10bjb, SN 2010mc, PTF 10weh, SN 2011ht,
and PTF 12cxj), three of which are reported here for the first time.
For each SN we calculate the control time. We find that precursor
events among SNe IIn are common: at the one-sided 99% confidence
level, >50% of SNe IIn have at least one pre-explosion outburst that
is brighter than 3x107 L☉ taking place up to 1/3 yr prior to
the SN explosion. The average rate of such precursor events during the
year prior to the SN explosion is likely ≳ 1/yr, and fainter
precursors are possibly even more common. Ignoring the two weakest
precursors in our sample, the precursors rate we find is still on the
order of one per year. We also find possible correlations between the
integrated luminosity of the precursor and the SN total radiated
energy, peak luminosity, and rise time. These correlations are
expected if the precursors are mass-ejection events, and the
early-time light curve of these SNe is powered by interaction of the
SN shock and ejecta with optically thick circumstellar material.
Description:
We used PTF observations of the SNe in our sample. The PTF data
reduction is described by Laher et al. (2014PASP..126..674L 2014PASP..126..674L), and the
photometric calibration is discussed by Ofek et al.
(2012PASP..124...62O 2012PASP..124...62O, 2012PASP..124..854O 2012PASP..124..854O). Our search is based on
image subtraction, and the flux residuals in the individual image
subtractions for all the SNe in our sample are listed in Table 2. In
order to calculate the rate of SN precursors, we need to estimate the
"control time"-that is, for how long each SN location was observed
(prior to its explosion) to a given limiting magnitude. Table 5 lists,
for each SN, the time bin windows (of 15 days) prior to the SN
explosion and the 5σ sensitivity depth at each window for bins
with more than five measurements (second channel), or the median
6σ limiting magnitudes at windows with fewer than six
measurements (first channel).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 119 21 SN Sample
refs.dat 79 25 References
table2.dat 74 5834 SN Observations
table5.dat 32 226 Control time
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See also:
B/sn : Asiago Supernova Catalogue (Barbon et al., 1999-)
J/other/Nat/494.65 : SN 2010mc outburst before explosion (Ofek+, 2013)
J/ApJ/824/6 : PTF obs. of a precursor to SNHunt 275 2015 May event
(Ofek+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- SN Supernova identifier
11- 17 A7 --- Type Type according to SN classification
19- 28 F10.6 deg RAdeg Aperture Right Ascension (J2000)
30- 39 A10 deg DEdeg Aperture Declinaison (J2000)
41 A1 --- l_RMagpeak ? Limit flag on RMagpeak
42- 46 F5.1 mag RMagpeak ? Peak absolute R band magnitude
47 A1 --- u_RMagpeak ? Uncertainty flag on RMagpeak
49- 54 F6.4 --- z ? SN redshift
56- 60 F5.2 mag DM ? Distance modulus
62- 66 A5 d trise ? MJD of the estimated start of the SN rise
67 A1 --- u_trise ? Uncertainty flag on trise
69- 73 A5 d tpeak ? MJD of the light-curve peak
74 A1 --- u_tpeak ? Uncertainty flag on tpeak
76- 79 F4.2 --- FAP ?=- False-alarm probability (1)
81- 89 A9 --- Name SN name as in table2
91-119 A29 --- Ref References, in refs.dat file
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Note (1): FAP is the false-alarm probability to detect a precursor by coadding
images in 15 day bins as estimated using the bootstrap method
(see Section 4.2). The values are based on 100 bootstrap simulations and are
therefore truncated to two figures after the decimal point. SNe with no data
are those in which the precursor is clearly detected in many individual
images and thus the bootstrap analysis on the coadded data is ineffective
(see Section 4.2).
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 40 A17 --- Aut Author's name
41- 79 A39 --- Com Comments
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- SN Supernova identifier
11 A1 --- Filter [Rg] Filter used in the observation
13- 22 F10.5 d Time Time relative to trise (in table1)
24- 34 F11.5 d MJD Modified Julian Date
36- 41 F6.3 mag mag Observed luptitude in Filter (1)
43- 50 F8.3 mag emag Error in mag
52- 57 F6.3 mag lmag Limiting magnitude
59- 66 F8.1 ct Flux Flux residual
68- 74 F7.1 ct e_Flux Error in Flux
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Note (1): Magnitude are calculated in luptitudes, and they have meaning only
when smaller than the limiting magnitude. A magnitude measure in
which the logarithm is replaced with a hyperbolic sine. Unlike normal
magnitudes, luptitudes are defined for negative fluxes
(Lupton, Gunn, & Szalay 1999AJ....118.1406L 1999AJ....118.1406L)
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- SN Supernova identifier
11- 16 F6.1 d Time Time relative to trise (in table1) (1)
18- 22 F5.2 mag Rmag Apparent PTF R band limiting magnitude
24- 29 F6.2 mag RMag Absolute PTF R band limiting magnitude
31- 32 I2 --- Num Number of measurements in time bin (2)
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Note (1): within each 15-day bin.
Note (2): For bins with Num < 6 we present the median of all 6σ
limiting magnitudes in the bin. We mark instances with Num = 1
(even if Num > 1).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 08-Mar-2017