J/MNRAS/498/2575 Rapidly evolving transients discovered by DES (Wiseman+, 2020)
The host galaxies of 106 rapidly evolving transients discovered by the Dark
Energy Survey.
Wiseman P., Pursiainen M., Childress M., Swann E., Smith M., Galbany L.,
Lidman C., Davis T.M., Gutierrez C.P., Moller A., Thomas B.P.,
Frohmaier C., Foley R.J., Hinton S.R., Kelsey L., Kessler R., Lewis G.F.,
Sako M., Scolnic D., Sullivan M., Vincenzi M., Abbott T.M.C., Aguena M.,
Allam S., Annis J., Bertin E., Bhargava S., Brooks D., Burke D.L.,
Carnero Rosell A., Carollo D., Carrasco Kind M., Carretero J., Costanzi M.,
da Costa L.N., Diehl H.T., Doel P., Everett S., Fosalba P., Frieman J.,
Garcia-Bellido J., Gaztanaga E., Glazebrook K., Gruen D., Gruendl R.A.,
Gschwend J., Gutierrez G., Hollowood D.L., Honscheid K., James D.J.,
Kuehn K., Kuropatkin N., Lima M., Maia M.A.G., Marshall J.L., Martini P.,
Menanteau F., Miquel R., Palmese A., Paz-Chinchon F., Plazas A.A.,
Romer A.K., Sanchez E., Scarpine V., Schubnell M., Serrano S.,
Sevilla-Noarbe I., Sommer N.E., Suchyta E., Swanson M.E.C., Tarle G.,
Tucker B.E., Tucker D.L., Varga T.N., Walker A.R., (The DES Collaboration)
<Mon. Not. R. Astron. Soc., 498, 2575-2593 (2020)>
=2020MNRAS.498.2575W 2020MNRAS.498.2575W (SIMBAD/NED BibCode)
ADC_Keywords: Transient ; Galaxies ; Positional data ; Redshifts ;
Abundances, peculiar ; Spectra, optical
Keywords: galaxies: abundances - galaxies: photometry -
galaxies: star formation - transients: supernovae
Abstract:
Rapidly evolving transients (RETs), also termed fast blue optical
transients, are a recently discovered group of astrophysical events
that display rapid luminosity evolution. RETs typically rise to peak
in less than 10d and fade within 30, a time-scale unlikely to be
compatible with the decay of Nickel-56 that drives conventional
supernovae (SNe). Their peak luminosity spans a range of
-15<Mg←22.5, with some events observed at redshifts greater than 1.
Their evolution on fast time-scales has hindered high-quality
follow-up observations, and thus their origin and explosion/emission
mechanism remains unexplained. In this paper, we present the largest
sample of RETs to date, comprising 106 objects discovered by the Dark
Energy Survey, and perform the most comprehensive analysis of RET host
galaxies. Using deep-stacked photometry and emission lines from OzDES
spectroscopy, we derive stellar masses and star formation rates (SFRs)
for 49 host galaxies, and metallicities ([O/H]) for 37. We find that
RETs explode exclusively in star-forming galaxies and are thus likely
associated with massive stars. Comparing RET hosts to samples of host
galaxies of other explosive transients as well as field galaxies, we
find that RETs prefer galaxies with high specific SFRs
(<log(sSFR)> ~-9.6), indicating a link to young stellar populations,
similar to stripped-envelope SNe. RET hosts appear to show a lack of
chemical enrichment, their metallicities akin to long-duration
gamma-ray bursts and superluminous SN host galaxies
(<12+log(O/H)> ∼9.4). There are no clear relationships between mass or
SFR of the host galaxies and the peak magnitudes or decline rates of
the transients themselves.
Description:
Our sample of RETs comprises 106 events discovered in the 5-yr DES-SN
transient survey. This number expands upon the 72 of Pursiainen et al.
(2018MNRAS.481..894P 2018MNRAS.481..894P, Cat. J/MNRAS/481/894) (P18). The first reason
for the increased sample size is the use of the fifth year of DES-SN,
as Pursiainen et al. (2018MNRAS.481..894P 2018MNRAS.481..894P, Cat. J/MNRAS/481/894) were
only able to make use of the first 4yr. By imposing the P18 selection
criteria on season 5, the sample is increased to 92 objects. The
second reason is an update to the sample selection technique, which
adds a further 14 transients.
Of the 106 objects in the sample, 96 have a host galaxy detected in
deep host galaxy photometry of Wiseman et al. (2020MNRAS.495.4040W 2020MNRAS.495.4040W)
when using the directional light radius method (Sullivan et al.
2006ApJ...648..868S 2006ApJ...648..868S) to associate hosts as per Wiseman et al.
(2020MNRAS.495.4040W 2020MNRAS.495.4040W). Of these, 49 have a host galaxy spectroscopic
redshift which we access through an internal release of the OzDES
Global Redshift Catalog (GRC; v.20200104). The full OzDES redshift
catalogue will be available alongside the public data release detailed
in Lidman et al. (2020MNRAS.496...19L 2020MNRAS.496...19L).
We also obtained redshifts for some transient hosts serendipitously as
part of the Looking at the Distant Universe with the MeerKAT Array
(LADUMA) survey (http://www.laduma.uct.ac.za). Objects for which the
host already had a publicly available redshift were not observed with
OzDES, but merged into the GRC none the less. In total we analyse 45
spectra, with a mean continuum SNR of 2.56/pixel.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 64 96 Host galaxy information for the 106 RETs in the
DES 5-yr sample
table2.dat 150 49 Host galaxy properties for the 49 DES RET host
galaxies with redshifts and host galaxy spectra
tablea1.dat 137 45 Emission line fluxes for DES RET host galaxies
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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- 11 A11 --- Name Transient name (DESNNANaaaa)
13- 20 F8.5 deg RAdeg Right ascension (J2000)
22- 30 F9.5 deg DEdeg Declination (J2000)
32- 36 F5.2 mag rmag r-band magnitude (1)
38- 41 F4.2 mag e_rmag Error on rmag
43- 49 F7.5 --- z ? Redshift
51 A1 --- f_z [cd ] Flag on z (2)
53- 58 A6 --- Survey Survey used for observation
60- 64 F5.2 h ExpTime ? Exposure time (3)
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Note (1): Apparent r-band Kron magnitude according to DES-SN deep coadds of
Wiseman et al. (2020MNRAS.495.4040W 2020MNRAS.495.4040W), not corrected for Galactic
foreground reddening
Note (2): Flag as follows:
c = Host targetted by OzDES but no redshift measurement possible
d = Host not targetted by OzDES
Note (3): Exposure time only given for spectra that we have used for line
measurements rather than just redshift
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Name Transient name (DESNNANaaaa)
13- 17 F5.2 [Msun] logM* Logarithm of the stellar mass
19- 22 F4.2 [Msun] e_logM* Lower error on logM*
24- 27 F4.2 [Msun] E_logM* Upper error on logM*
29- 33 F5.2 [Msun/yr] logSFR Logarithm of the star formation rate
35- 38 F4.2 [Msun/yr] e_logSFR Lower error on logSFR
40- 43 F4.2 [Msun/yr] E_logSFR Upper error on logSFR
45- 50 F6.2 [yr-1] logsSFR Logarithm of the specific star
formation rate
52- 55 F4.2 [yr-1] e_logsSFR Lower error on logsSFR
57- 60 F4.2 [yr-1] E_logsSFR Upper error on logsSFR
62- 65 F4.2 [-] OHBest ? Best 12+log(O/H) estimation (1)
67- 70 F4.2 [-] e_OHBest ? Lower error on OHBest
72- 75 F4.2 [-] E_OHBest ? Upper error on OHBest
77- 80 F4.2 [-] OHD16 ? 12+log(O/H) determined using the S2N2
diagnostic of Dopita et al.
(2016Ap&SS.361...61D 2016Ap&SS.361...61D) (D16)
82- 85 F4.2 [-] e_OHD16 ? Lower error on OHD16
87- 90 F4.2 [-] E_OHD16 ? Upper error on OHD16
92- 95 F4.2 [-] OHN2 ? 12+log(O/H) determined with the N2
indicator and the calibration of
Pettini & Pagel (2004MNRAS.348L..59P 2004MNRAS.348L..59P)
(PP04)
97- 100 F4.2 [-] e_OHN2 ? Lower error on OHN2
102- 105 F4.2 [-] E_OHN2 ? Upper error on OHN2
107- 110 F4.2 [-] OHO3N2 ? 12+log(O/H) determined using the O3N2
indicator and the calibration of
Pettini & Pagel (2004MNRAS.348L..59P 2004MNRAS.348L..59P)
(PP04)
112- 115 F4.2 [-] e_OHO3N2 ? Lower error on OHO3N2
117- 120 F4.2 [-] E_OHO3N2 ? Upper error on OHO3N2
122- 125 F4.2 [-] OHR23 ? 12+log(O/H) determined using the R23
indicator and the calibration from
Kobulnicky & Kewley
(2004ApJ...617..240K 2004ApJ...617..240K,
Cat. J/ApJ/617/240) (KK04)
127- 130 F4.2 [-] e_OHR23 ? Lower error on OHR23
132- 135 F4.2 [-] E_OHR23 ? Upper error on OHR23
137- 140 F4.2 [-] OHO3N2mean ? Weighted average of OHN2, OHO3N2 and
OHR23 (2)
142- 145 F4.2 [-] e_OHO3N2mean ? Lower error on OHO3N2mean
147- 150 F4.2 [-] E_OHO3N2mean ? Upper error on OHO3N2mean
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Note (1): Linear combination of the likelihoods for D16, PP04 N2, PP04 O3N2,
KK04 R23
Note (2): N2 and R23 were converted to PP04 O3N2 via Kewley & Ellison
(2008ApJ...681.1183K 2008ApJ...681.1183K)
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Transient name (DESNNANaaaa)
13- 18 F6.2 10-2W/m2/nm FOII3727 OII 3727Å emission line flux (1)
20- 24 F5.2 10-2W/m2/nm e_FOII3727 Error on FOII3727
26- 30 F5.2 10-2W/m2/nm FOIII4960 ? OIII 4960Å emission line flux (1)
32- 35 F4.2 10-2W/m2/nm e_FOIII4960 ? Error on FOIII4960
37- 42 F6.2 10-2W/m2/nm FOIII5007 ? OIII 5007Å emission line flux (1)
44- 47 F4.2 10-2W/m2/nm e_FOIII5007 ? Error on FOIII5007
49- 53 F5.2 10-2W/m2/nm FNII6549 ? NII 6549Å emission line flux (1)
55- 58 F4.2 10-2W/m2/nm e_FNII6549 ? Error on FNII6549
60- 64 F5.2 10-2W/m2/nm FNII6585 ? NII 6585Å emission line flux (1)
66- 69 F4.2 10-2W/m2/nm e_FNII6585 ? Error on FNII6585
71- 75 F5.2 10-2W/m2/nm FSII6717 ? SII 6717Å emission line flux (1)
77- 80 F4.2 10-2W/m2/nm e_FSII6717 ? Error on FSII6717
82- 86 F5.2 10-2W/m2/nm FSII6731 ? SII 6731Å emission line flux (1)
88- 91 F4.2 10-2W/m2/nm e_FSII6731 ? Error on FSII6731
93- 97 F5.2 10-2W/m2/nm FHdelta Hδ emission line flux (1)
99- 102 F4.2 10-2W/m2/nm e_FHdelta Error on FHdelta
104- 108 F5.2 10-2W/m2/nm FHgamma Hγ emission line flux (1)
110- 113 F4.2 10-2W/m2/nm e_FHgamma Error on FHgamma
115- 120 F6.2 10-2W/m2/nm FHbeta ? Hβ emission line flux (1)
122- 125 F4.2 10-2W/m2/nm e_FHbeta ? Error on FHbeta
127- 132 F6.2 10-2W/m2/nm FHalpha ? Hα emission line flux (1)
134- 137 F4.2 10-2W/m2/nm e_FHalpha ? Error on FHalpha
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Note (1): Emission line fluxes have been corrected for Milky Way reddening
using Schlegel, Finkbeiner & Davis (1998ApJ...500..525S 1998ApJ...500..525S) assuming a
Cardelli, Clayton & Mathis (1989ApJ...345..245C 1989ApJ...345..245C) reddening law with
RV=3.1, but have not been corrected for intrinsic host galaxy
reddening
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 04-Aug-2023