J/ApJ/875/136 BVRI, spectra & IR obs. of type II-P SN2017eaw (Van Dyk+, 2019)
The Type II-plateau supernova 2017eaw in NGC 6946 and its red supergiant
progenitor.
Van Dyk S.D., Zheng W., Maund J.R., Brink T.G., Srinivasan S.,
Andrews J.E., Smith N., Leonard D.C., Morozova V., Filippenko A.V.,
Conner B., Milisavljevic D., de Jaeger T., Long K.S., Isaacson H.,
Crossfield I.J.M., Kosiarek M.R., Howard A.W., Fox O.D., Kelly P.L.,
Piro A.L., Littlefair S.P., Dhillon V.S., Wilson R., Butterley T.,
Yunus S., Channa S., Jeffers B.T., Falcon E., Ross T.W., Hestenes J.C.,
Stegman S.M., Zhang K., Kumar S.
<Astrophys. J., 875, 136-136 (2019)>
=2019ApJ...875..136V 2019ApJ...875..136V (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae; Photometry, UBVRI; Spectra, optical
Keywords: galaxies: distances and redshifts; galaxies: individual: NGC 6946;
stars: massive; supergiants; supernovae: general;
supernovae: individual: SN 2017eaw
Abstract:
We present extensive optical photometric and spectroscopic
observations, from 4 to 482 days after explosion, of the
Type II-plateau (II-P) supernova (SN) 2017eaw in NGC 6946. SN 2017eaw
is a normal SN II-P intermediate in properties between, for example,
SN 1999em and SN 2012aw and the more luminous SN 2004et, also in
NGC6946. We have determined that the extinction to SN 2017eaw is
primarily due to the Galactic foreground and that the SN site
metallicity is likely subsolar. We have also independently confirmed a
tip-of-the-red-giant-branch (TRGB) distance to NGC 6946 of
7.73±0.78Mpc. The distances to the SN that we have also estimated
via both the standardized candle method and expanding photosphere
method corroborate the TRGB distance. We confirm the SN progenitor
identity in pre-explosion archival Hubble Space Telescope (HST) and
Spitzer Space Telescope images, via imaging of the SN through our HST
Target of Opportunity program. Detailed modeling of the progenitor's
spectral energy distribution indicates that the star was a dusty,
luminous red supergiant consistent with an initial mass of ∼15M☉.
Description:
Multiband BVRI images of SN 2017eaw were obtained with both the
Katzman Automatic Imaging Telescope (KAIT) and the 1m Nickel telescope
at Lick Observatory. Unfiltered images were also obtained with KAIT.
We also obtained near-daily BVRI coverage with the pt5m, a 0.5m
robotic telescope at the Roque de los Muchachos Observatory, La Palma.
Exposure times for these observations were 5x15s for both B and I, and
5x10s for both V and R, prior to 2017 October 26. From that date
onward, exposure times were 5x45s for both B and I, and 5x40s for both
V and R. See Table 1, Fig 2 (and Section 2.1).
Over an eight-month period beginning on 2017 May 19, a series of 20
optical spectra of SN 2017eaw were obtained with the Kast double
spectrograph mounted on the 3m Shane telescope at Lick Observatory.
With the Blue Channel (BC) spectrograph on the MMT we also obtained
nine spectra with the 1200lines/mm grating, with a central wavelength
of 6360Å and a 1.0" slit width, and two spectra with the
300lines/mm grating.
We also obtained five epochs of optical spectroscopy with the Boller &
Chivens (B&C) spectrograph mounted on the 2.3m Bok telescope on Kitt
Peak. See Fig 3.
Additionally, some of us (H.I., I.J.M.C., D.H., M.R.K.) obtained an
optical spectrum of SN 2017eaw with the HIRES spectrometer on the
KeckI 10m telescope on Maunakea on 2017 June 2.
See Table 2 and Section 2.2.
The site of SN 2017eaw was observed serendipitously by several HST
programs prior to explosion. These include GO-14156 (PI A. Leroy) with
the Wide Field Camera 3 (WFC3) IR channel in bands F110W (total
exposure 455.87s) and F128N (1411.74s) on 2016 February 9, and
GO-14638 (PI K. Long) with WFC3/IR F160W (396.93s) on 2016 October 24;
and GO-9788 (PI L. Ho) with the Advanced Camera for Surveys (ACS) Wide
Field Channel (WFC) on 2004 July 29 in F658N (700s) and F814W (120s),
and GO-14786 (PI B. Williams) with ACS/WFC on 2016 October 26 in F814W
(2570s) and F606W (2430s).
The SN site was also serendipitously observed pre-explosion by a
number of programs on various dates, from 2004 June 10 to 2017 March 31,
using Spitzer. We list all of these observations and the data that we
considered in Table 3. See Sections 2.4 and 7.2.
Finally, we observed SN 2017eaw on 2017 May 29.79 with HST WFC3/UVIS
in subarray mode in F814W (270s total exposure), as part of our Target
of Opportunity (ToO) program (GO-14645, PI S. Van Dyk). See Section 2.5.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
20 34 44.24 +60 11 35.9 SN 2017eaw = SPIRITS18k
----------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 29 25 Photometric sequence around SN 2017eaw
table2.dat 62 37 Log of optical spectroscopy of SN 2017eaw
table3.dat 41 45 Log of Spitzer data covering the SN 2017eaw site
table5.dat 51 12 Photometry of the SN 2017eaw progenitor
fig2.dat 86 274 The BVRI and unfiltered light curves of SN 2017eaw
fig3.dat 44 105516 Sequence of Kast, MMT, and Bok spectra of
SN 2017eaw (36 observation dates)
fig15.dat 52 19 *Expansion velocity evolution of SN 2017eaw
fig21.dat 148 38 Apparent brightness of the SN 2017eaw progenitor
in the Spitzer 3.6µm and 4.5µm bands
over ∼12.9yr prior to explosion
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Note on fig15.dat: We measured the evolution of the expansion velocity of
SN 2017eaw from our multi-epoch spectra, starting with our earliest
spectrum on day 5.2 through well off the plateau on day 151.9.
See Section 6.5.
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See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/A+A/442/281 : Late-type giants BVRIJHKL & Teff (Kucinskas+, 2005)
J/MNRAS/372/1315 : UBVRI photometry of SN 2004et (Sahu+, 2006)
J/MNRAS/395/1409 : Type II-P SN progenitor constraints (Smartt+, 2009)
J/ApJ/705/1364 : MIR catalog of point sources in M33 (Thompson+, 2009)
J/ApJS/190/418 : Light curves for 165 SNe (Ganeshalingam+, 2010)
J/MNRAS/412/1441 : SNe luminosity functions (Li+, 2011)
J/A+A/532/A54 : GRAMS carbon-star model grid (Srinivasan+, 2011)
J/MNRAS/425/1789 : Berkeley supernova Ia program. I. (Silverman+, 2012)
J/ApJ/750/99 : The Pan-STARRS1 photometric system (Tonry+, 2012)
J/MNRAS/433/1871 : UBVRI griz light curves of SN 2012aw (Bose+, 2013)
J/A+A/553/A24 : Models for rotating stars (Georgy+, 2013)
J/MNRAS/442/844 : BVRI light curves of type II-P supernovae (Faran+, 2014)
J/ApJ/791/105 : SNe progenitor masses (Williams+, 2014)
J/ApJ/799/215 : 26 type II-Plateau supernovae parameters (Pejcha+, 2015)
J/MNRAS/449/1876 : Photometric observations of SN PTF11iqb (Smith+, 2015)
J/ApJ/826/56 : HST/WFC3 obs. of Cepheids in SN Ia host gal. (Riess+, 2016)
J/MNRAS/459/3939 : Type II supernova light curves (Valenti+, 2016)
J/ApJ/859/73 : Variability of RSGs in M31 from iPTF (Soraisam+, 2018)
J/ApJ/860/39 : HST obs. of nearby core-collapse SNe (Williams+, 2018)
J/MNRAS/487/832 : BVRI photometry of the Type II-P SN 2017eaw (Buta+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Star Photometric sequence star in Figure 1 (1)
3- 8 F6.3 mag Bmag [14.78/18.49] The B band magnitude (2)
10- 15 F6.3 mag Vmag [14.13/17.39] The V band magnitude (2)
17- 22 F6.3 mag Rmag [13.75/16.76] The R band magnitude (2)
24- 29 F6.3 mag Imag [13.33/16.12] The I band magnitude (2)
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Note (1): Photometric sequence of calibration stars in Figure 1:
KAIT R-band image from 2017 June 23.
Note (2): The uncertainties in these magnitudes are those from the
PS1-to-Johnson-Cousins transformations from Tonry+ (2012, J/ApJ/750/99),
i.e., 0.034, 0.012, 0.015, and 0.017mag in B, V, R, and I,
respectively (the uncertainties in the observed PS1 magnitudes for
these stars are all ≪0.01mag).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 14 A14 "datime" Date UT of the observation date
16- 24 F9.3 d MJD [57890.9/58367.9] Modified Julian Date
26- 30 F5.1 d Age [5.2/482.1] SN Age in days (1)
32- 38 A7 --- Inst Spectrograph used for the observation
40- 52 A13 0.1nm lambda Spectral wavelength range in Angstroms
54- 62 A9 0.1nm Res Spectral resolution in Angstroms
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Note (1): The age is referenced to our estimate of the date of explosion:
JD 2457885.7.
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1- 8 A8 "date" Date UT of the observation date
10- 17 I8 --- AORKEY Unique Spitzer observation identifier
19- 41 A23 --- Data Spitzer instruments and channels (1)
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Note (1): Channel numbers are the central wavelength in microns.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Inst HST or Spitzer camera or Instrument (1)
14- 18 A5 --- Band Filter band (HST) or Instrument channel
20- 27 A8 "date" Date1 UT observation date (2)
29 A1 --- --- [-]
31- 38 A8 "date" Date2 UT observation date (2)
40 A1 --- l_mag Limit flag on mag
41- 45 F5.2 mag mag [10.39/26.4] Observed brightness in Band
47- 51 F5.3 mag e_mag [0.01/0.05]? Uncertainty in mag
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Note (1): Spitzer IRAC ch1, 3.6um; ch2, 4.5um; ch3, 5.8um; ch4, 8.0um.
Spitzer MIPS ch1, 24um.
Note (2): The Spitzer measurements were made from a coaddition of data
obtained in the particular band during the indicated date range.
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Byte-by-byte Description of file: fig2.dat
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Bytes Format Units Label Explanations
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1- 12 A12 "datime" Date UT Date
14- 22 F9.3 d MJD Modified Julian date
24- 28 F5.2 mag Bmag [13.13/18.19]? Apparent B band magnitude
30- 34 F5.2 mag e_Bmag [0.01/0.3]? The 1σ uncertainty in Bmag
36- 40 F5.2 mag Vmag [12.84/16.71]? Apparent V band magnitude
42- 46 F5.2 mag e_Vmag [0.01/0.16]? The 1σ uncertainty in Vmag
48- 52 F5.2 mag mag [12.49/15.59]? Apparent KAIT unfiltered magnitude
54- 57 F4.2 mag e_mag [0.01/0.06]? The 1σ uncertainty in Unfiltmag
59- 63 F5.2 mag Rmag [12.44/15.46]? Apparent R band magnitude
65- 68 F4.2 mag e_Rmag [0.01/0.06]? The 1σ uncertainty in Rmag
70- 74 F5.2 mag Imag [12.19/14.79]? Apparent I band magnitude
76- 79 F4.2 mag e_Imag [0.01/0.08]? The 1σ uncertainty in Imag
81- 86 A6 --- Tel Telescope on which observation was obtained (1)
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Note (1): Instrument as follows:
KAIT = Katzman Automatic Imaging Telescope at Lick Observatory
(159 occurrences)
pt5m = the 1m Nickel telescope at Lick Observatory (84 occurrences)
Nickel = 0.5m robotic telescope at the Roque de los Muchachos Observatory,
La Palma (31 occurrences)
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Byte-by-byte Description of file: fig3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1- 14 A14 "datime" Date UT date of observation (from 2017-05-17.402
to 2018-09-06.316)
16- 19 A4 --- Inst Instrument (MMT, Kast or Bok) (1)
21 A1 --- Filt [RV] Recalibration filter (2)
23- 31 F9.3 0.1nm lambda [3245/10720] Rest Wavelength in Angstroms
33- 44 E12.7 cW/m2/nm Flux [6.78e-22/4.51e-14]?=0 Flux
in erg/cm2/s/Angstrom (2)
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Note (1): Instrument as follows:
MMTv = MMT Blue Channel Spectrograph 300l/mm grating for V-band recalibration
(5176 occurrences)
MMTr = MMT Blue Channel Spectrograph 1200l/mm grating for R-band recalibration
(24106 occurrences)
Kast = The Kast double spectrograph mounted on the 3m Shane telescope
at Lick Observatory (70389 occurrences)
Bok = Obtained with the Bok 2.3-m Boller & Chivens spectrograph,
300l/mm grating (5845 occurrences).
Note (2): Recalibrated to the SN light curve at V or R-band by
linear extrapolation.
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Byte-by-byte Description of file: fig15.dat
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Bytes Format Units Label Explanations
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1- 5 F5.1 d Age [5.2/149.9] Age of SN 2017eaw
7- 11 I5 km/s vHa [5220/12988] H-alpha expansion velocity
absorption feature
13- 16 I4 km/s e_vHa [71/1090] Uncertainty in vHalpha
18- 22 I5 km/s vHeI [10297/10320]? HeI 5876Å expansion
velocity absorption line
24- 25 I2 km/s e_vHeI [20/58]? Uncertainty in vHeI
27- 30 I4 km/s vFeII4924 [2404/5221]? FeII 4924Å expansion
velocity absorption line
32- 34 I3 km/s e_vFeII4924 [49/216]? Uncertainty in the vFeII4924
36- 39 I4 km/s vFeII5018 [2770/7943]? FeII 5018Å expansion
velocity absorption line
41- 43 I3 km/s e_vFeII5018 [38/196]? Uncertainty in the vFeII5018
45- 48 I4 km/s vFeII5169 [2289/7973]? FeII 5169Å expansion
velocity absorption line
50- 52 I3 km/s e_vFeII5169 [47/200]? Uncertainty in the vFeII5169
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Byte-by-byte Description of file: fig21.dat
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Bytes Format Units Label Explanations
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1- 8 A8 d MJD Modified Julian Date
10- 14 F5.2 yr Year [0.1/12.93] Years before SN 2017eaw explosion
(JD 2457885.7)
16- 20 F5.2 mag 3.6magP [17.75/18.26]? Magnitude of Progenitor
in Spitzer/IRAC Ch1 (3.6um)
22- 25 F4.2 mag e_3.6magP [0.03/0.08]? Uncertainty in 3.6magP (1)
27- 31 F5.2 mag 4.5magP [17.55/18.08]? Magnitude of Progenitor
in Spitzer/IRAC Ch2 (4.5um)
33- 36 F4.2 mag e_4.5magP [0.04/0.15]? Uncertainty in 4.5magP (1)
38- 42 F5.2 mag 3.6magO1 [17.35/18.09]? Object 1 Spitzer/IRAC Ch1
magnitude (3.6um) (2)
44- 47 F4.2 mag e_3.6magO1 [0.03/0.07]? Uncertainty in 3.6magO1 (1)
49- 53 F5.2 mag 4.5magO1 [17.68/18.38]? Object 1 Spitzer/IRAC Ch2
magnitude (4.5um) (2)
55- 58 F4.2 mag e_4.5magO1 [0.05/0.17]? Uncertainty in 4.5mag01 (1)
60- 64 F5.2 mag 3.6magO2 [17.21/19.06]? Object 2 Spitzer/IRAC Ch1
magnitude (3.6um) (2)
66- 69 F4.2 mag e_3.6magO2 [0.03/0.14]? Uncertainty in 3.6magO2 (1)
71- 75 F5.2 mag 4.5magO2 [17.35/18.8]? Object 2 Spitzer/IRAC Ch2
magnitude (4.5um) (2)
77- 80 F4.2 mag e_4.5magO2 [0.04/0.14]? Uncertainty in 4.5mag02 (1)
82-148 A67 --- Comm ? Comments on Detection of Progenitor
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Note (1): Formal magnitude uncertainties based on S/N ratio from MOPEX/APEX.
Note (2): Object 1 is 3.5 arcsec SW of the progenitor;
Object 2 is 13.2 arcsec SW of the progenitor.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 10-Sep-2020