J/ApJ/824/6 PTF obs. of a precursor to SNHunt 275 2015 May event (Ofek+, 2016)
PTF13efv --An outburst 500 days prior to the SNHunt 275 explosion and its
radiative efficiency.
Ofek E.O., Cenko S.B., Shaviv N.J., Duggan G., Strotjohann N.-L., Rubin A.,
Kulkarni S.R., Gal-Yam A., Sullivan M., Cao Y., Nugent P.E., Kasliwal M.M.,
Sollerman J., Fransson C., Filippenko A.V., Perley D.A., Yaron O., Laher R.
<Astrophys. J., 824, 6-6 (2016)>
=2016ApJ...824....6O 2016ApJ...824....6O (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Photometry, UBVRI ; X-ray sources
Keywords: stars: mass-loss; supernovae: general;
supernovae: individual: "PTF13efv, SNHunt275"
Abstract:
The progenitors of some supernovae (SNe) exhibit outbursts with
super-Eddington luminosities prior to their final explosions. This
behavior is common among SNe IIn, but the driving mechanisms of these
precursors are not yet well-understood. SNHunt 275 was announced as a
possible new SN during 2015 May. Here we report on pre-explosion
observations of the location of this event by the Palomar Transient
Factory (PTF) and report the detection of a precursor about 500 days
prior to the 2015 May activity (PTF 13efv). The observed velocities in
the 2015 transient and its 2013 precursor absorption spectra are low
(1000-2000km/s), so it is not clear yet if the recent activity indeed
marks the final disruption of the progenitor. Regardless of the nature
of this event, we use the PTF photometric and spectral observations,
as well as Swift-UVOT observations, to constrain the efficiency of the
radiated energy relative to the total kinetic energy of the precursor.
We find that, using an order-of-magnitude estimate and under the
assumption of spherical symmetry, the ratio of the radiated energy to
the kinetic energy is in the range of 4x10-2 to 3.4x103.
Description:
The Palomar Transient Factory (PTF and iPTF; Law et al.
2009PASP..121.1395L 2009PASP..121.1395L; Rau et al. 2009PASP..121.1334R 2009PASP..121.1334R), using the 48inch
Oschin Schmidt telescope, observed the field of SNHunt 275 starting in
2009 March. On 2013 December 12, PTF detected a new source at the
location of the event, and the transient was named PTF 13efv (see
Figure 1). Three images obtained between 2014 January 23 and April 25
were used as a reference. The PTF R-band photometry is listed in Table1.
Most of the optical spectra were obtained with the Low Resolution
Imaging Spectrometer (LRIS) on the Keck I 10m telescope, although a
few spectra were also taken with the DEep Imaging Multi-Object
Spectrograph (DEIMOS) on the Keck II 10m telescope, the Kast
spectrograph on the Shane 3m telescope at Lick Observatory, and the
Gemini-North Multiobject Spectrograph (GMOS) on the 8m Gemini-N
telescope. The first spectrum was obtained during the 2013 December
outburst.
We used the Swift/UVOT observations of SNHunt 275, since 2008, to
construct the bolometric light curve of the transient.
The log of Swift-XRT observations, along with the source and
background X-ray counts in the individual observations, is given in
Table 5.
Objects:
----------------------------------------------------------------
RA (ICRS) DE Designation(s) (Distance)
----------------------------------------------------------------
09 09 34.96 +33 07 20.4 SNHunt 275 = SN 2015bh (D=30Mpc)
09 09 34.96 +33 07 20.4 PTF 13efv = PTF 13efv
----------------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 36 45 PTF photometric observations
table3.dat 27 275 Swift-UVOT photometric observations
table5.dat 23 94 Swift-XRT observations
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See also:
B/sn : Asiago Supernova Catalogue (Barbon et al., 1999-)
II/313 : Palomar Transient Factory (PTF) photometric catalog 1.0 (Ofek+, 2012)
J/ApJ/811/117 : R-band PTF observations of SNe IIb (Strotjohann+, 2015)
J/ApJ/782/42 : Panchromatic observations of PTF11qcj (Corsi+, 2014)
J/ApJ/781/42 : Optical photometry of SN 2010jl (Ofek+, 2014)
J/ApJ/768/47 : Swift/XRT 0.2-10keV observations of SN2009ip (Ofek+, 2013)
J/other/Nat/494.65 : SN 2010mc outburst before explosion (Ofek+, 2013)
J/ApJ/763/L27 : RI light curves of the type IIn SN 2009ip (Prieto+, 2013)
J/ApJ/702/226 : Swift/UVOT panchromatic obs. of SN 2008D (Modjaz+, 2009)
J/ApJ/696/870 : Catalina Real-time Transient Survey (CRTS) (Drake+, 2009)
J/AJ/137/4517 : UVOT light curves of supernovae (Brown+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.4 d MJD Modified Julian Date
12- 17 F6.1 ct Cts [-174/531] Observed counts
19- 23 F5.1 ct e_Cts [47/164] Error in Cts
25 A1 --- l_Rmag Lower limit flag on mag (1)
27- 31 F5.2 mag Rmag [20.1/21.7] Image-subtraction-based PTF R-band
AB magnitude (2)
33- 36 F4.2 mag e_Rmag [0.1/0.4]?=9.99 Error in Rmag
--------------------------------------------------------------------------------
Note (1): When the detection is less than 3σ than the noise level.
Note (2): The count rate can be converted to AB magnitude with
Rmag=27-2.5log10(Cts).
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- Filt Swift/UVOT filter identifier (U,B,V, UM2, UW1
or UW2)
5- 14 F10.4 d T-t0 [-2686/15.5] Time since JD=2457157.36717
16- 21 F6.3 ct Flux [0.07/39] Background subtracted counts in Filt (1)
23- 27 F5.3 ct e_Flux [0.006/1.8] Error in Flux
--------------------------------------------------------------------------------
Note (1): Where the background is estimated as the mean of all the observations
in a given filter obtained before 2015 Jan. 1. The subtracted
backgrounds are 0.892, 1.496, 0.743, 0.085, 0.206, and 0.146 counts
for the V, B, U, UV M2, UV W1, and UV W2 filters, respectively. The
zero points to convert these counts to AB magnitudes are 17.88,
18.99, 19.36, 18.97, 18.53, and 19.07mag, for the V, B, U, UV W1,
UV M2, and UV W2 filters, respectively.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.3 d T-t0 [-2686/23.3] Time since JD=2457157.36717
11- 17 F7.1 s Exp [54/28650] Exposure time
19 I1 ct Src [0/3] Source counts in the 0.2-10keV band (1)
21- 23 I3 ct Bck [0/124] Background counts (0.2-10keV) (2)
--------------------------------------------------------------------------------
Note (1): In a 9 arcsec radius aperture of the source position.
Note (2): The number of counts in an annulus of inner (outer) radius of
50 arcsec (100 arcsec) around the source. The ratio between the
background annulus area and the aperture area is 92.59.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 10-Aug-2016