J/ApJ/815/63 SDSS wide double white dwarfs spectroscopy (Andrews+, 2015)
Constraints on the initial-final mass relation from wide double white dwarfs.
Andrews J.J., Agueros M.A., Gianninas A., Kilic M., Dhital S.,
Anderson S.F.
<Astrophys. J., 815, 63 (2015)>
=2015ApJ...815...63A 2015ApJ...815...63A (SIMBAD/NED BibCode)
ADC_Keywords: Stars, white dwarf ; Stars, double and multiple ; Stars, masses ;
Stars, distances ; Effective temperatures ; Photometry, SDSS
Keywords: binaries: general; binaries: visual; stars: evolution; white dwarfs
Abstract:
We present observational constraints on the initial-final mass
relation (IFMR) using wide double white dwarfs (DWDs). We identify 65
new candidate wide DWDs within the Sloan Digital Sky Survey, bringing
the number of candidate wide DWDs to 142. We then engage in a
spectroscopic follow-up campaign and collect existing spectra for
these objects; using these spectra, we derive masses and cooling ages
for 54 hydrogen (DA) WDs in DWDs. We also identify one new DA/DB pair,
four candidate DA/DC pairs, four candidate DA/DAH pairs, and one new
candidate triple degenerate system. Because wide DWDs are co-eval and
evolve independently, the difference in the pre-WD lifetimes should
equal the difference in the WD cooling ages. We use this to develop a
Bayesian hierarchical framework and construct a likelihood function to
determine the probability that any particular IFMR fits a sample of
wide DWDs. We then define a parametric model for the IFMR and find the
best parameters indicated by our sample of DWDs. We place robust
constraints on the IFMR for initial masses of 2-4M☉. The WD
masses produced by our model for stars within this mass range differ
from those predicted by semi-empirical fits to open cluster WDs.
Within this mass range, where there are few constraining open cluster
WDs and disagreements in the cluster ages, wide DWDs may provide more
reliable constraints on the IFMR. Expanding this method to the many
wide DWDs expected to be discovered by Gaia may transform our
understanding of the IFMR.
Description:
We engaged in a campaign to obtain spectra for WDs in wide double
white dwarfs (DWDs). Our targets included the new systems identified
in Paper I (Andrews+, 2012ApJ...757..170A 2012ApJ...757..170A), those photometrically
selected from SDSS-DR9, and WDs from pairs in the literature that
lacked spectroscopy.
Roughly 50 systems have g≤19mag, making them ideal targets for the
3.5-m telescope at Apache Point Observatory (APO), NM. Over 13 half
nights between 2012 and 2013 September, we observed 34 pairs with the
Dual Imaging Spectrograph in its high-resolution mode (R∼2500 at
Hβ), which provides coverage from 3800 to 5000Å on the blue
CCD.
Additionally, high-resolution Very Large Telescope (VLT; R∼15000)
spectra for ∼10 WDs from the Supernova Progenitor Survey (Koester et
al. 2009, J/A+A/505/441) were provided by D. Koester (2015, private
communication).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 156 142 Properties of candidate and confirmed wide double
white dwarfs (DWDs)
table3.dat 81 56 Fit results for the DA/DA double white dwarf
spectroscopic sample
table4.dat 68 19 DA/DA DWDs used to constrain the initial-final
mass relation (IFMR)
table7.dat 97 45 Fit results for the non-DA/DA spectroscopic sample
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See also:
V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
J/AJ/150/57 : SLoWPoKES-II catalog (Dhital+, 2015)
J/MNRAS/446/4078 : New white dwarf stars in SDSS DR10 (Kepler+, 2015)
J/A+A/565/A11 : Gaia photometry for white dwarfs (Carrasco+, 2014)
J/ApJS/204/5 : SDSS DR7 white dwarf catalog (Kleinman+, 2013)
J/MNRAS/433/3398 : SDSS white dwarf MS binaries (Rebassa-Mansergas+, 2013)
J/ApJ/743/138 : Spectroscopic survey of bright white dwarfs (Gianninas+, 2011)
J/MNRAS/417/1210 : DA-white dwarfs from SDSS and UKIDSS (Girven+, 2011)
J/ApJ/730/67 : Radial velocities of low-mass white dwarfs (Brown+, 2011)
J/ApJ/704/531 : The coevality of young binary systems (Kraus+, 2009)
J/A+A/505/441 : UVES/VLT spectra of white dwarfs (Koester+, 2009)
J/AJ/131/1674 : Close binary systems from SDSS DR4 (Silvestri+, 2006)
J/AJ/131/582 : Cool white dwarfs in the SDSS (Kilic+, 2006)
J/ApJS/161/394 : Low-luminosity companions to white dwarfs (Farihi+, 2005)
J/ApJ/631/1100 : Atmospheric parameters of DA white dwarfs (Gianninas+, 2005)
J/ApJS/156/47 : DA white dwarfs from the Palomar Green Survey (Liebert+, 2005)
http://www.sdss3.org/ : SDSS-III home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- DWD Double White Dwarf Name
21- 22 I2 h RAh White Dwarf 1, Hour of Right Ascension (J2000)
24- 25 I2 min RAm White Dwarf 1, Minute of Right Ascension (J2000)
27- 31 F5.2 s RAs White Dwarf 1, Second of Right Ascension (J2000)
33- 33 A1 --- DE- White Dwarf 1, Sign of the Declination (J2000)
34- 35 I2 deg DEd White Dwarf 1, Degree of Declination (J2000)
37- 38 I2 arcmin DEm White Dwarf 1, Arcminute of Declination (J2000)
40- 44 F5.2 arcsec DEs White Dwarf 1, Arcsecond of Declination (J2000)
46- 47 I2 h RA2h ? White Dwarf 2, Hour of Right Ascension (J2000)
49- 50 I2 min RA2m ? White Dwarf 2, Minute of Right Ascension (J2000)
52- 56 F5.2 s RA2s ? White Dwarf 2, Second of Right Ascension (J2000)
58 A1 --- DE2- ? White Dwarf 2, Sign of the Declination (J2000)
59- 60 I2 deg DE2d ? White Dwarf 2, Degree of Declination (J2000)
62- 63 I2 arcmin DE2m ? White Dwarf 2, Arcminute of Declination (J2000)
65- 69 F5.2 arcsec DE2s ? White Dwarf 2, Arcsecond of Declination (J2000)
71- 75 F5.2 mag gmag1 [13.9/21]? White Dwarf 1, SDSS g magnitude
77- 80 F4.2 mag e_gmag1 [0/0.2]? Uncertainty in gmag1
82- 86 F5.2 mag gmag2 [14.4/21.3]? White Dwarf 2, SDSS g magnitude
88- 91 F4.2 mag e_gmag2 [0/0.3]? Uncertainty in gmag2
93- 99 F7.2 mas/yr pmRA1 [-288/239]? White Dwarf 1, Proper Motion in RA
101-104 F4.2 mas/yr e_pmRA1 [1.5/6]? Uncertainty in pmRA1
106-113 F8.2 mas/yr pmDE1 [-1788/165]? White Dwarf 1, Proper Motion in DE
115-118 F4.2 mas/yr e_pmDE1 [1.5/6]? Uncertainty in pmDE1
120-126 F7.2 mas/yr pmRA2 [-296/209]? White Dwarf 2, Proper Motion in RA
128-131 F4.2 mas/yr e_pmRA2 [1.5/6]? Uncertainty in pmRA2
133-140 F8.2 mas/yr pmDE2 [-1784/156]? White Dwarf 2, Proper Motion in DE
142-145 F4.2 mas/yr e_pmDE2 [1.5/6]? Uncertainty in pmDE2
147-150 F4.1 arcsec theta [1/97]? Angular separation θ
152-152 A1 --- Sp [Y/N] Targeted for spectroscopy?
154-156 A3 --- Ref Reference(s) (1)
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Note (1): Reference as follows:
1 = This work;
2 = Paper I, Andrews et al. (2012ApJ...757..170A 2012ApJ...757..170A);
3 = Baxter et al. (2014MNRAS.440.3184B 2014MNRAS.440.3184B)
4 = Literature, see Andrews et al. (2012ApJ...757..170A 2012ApJ...757..170A) for cross-references
5 = Poleski et al. (2012AcA....62....1P 2012AcA....62....1P)
6 = Scholz et al. (2002ApJ...565..539S 2002ApJ...565..539S)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- DWD Double White Dwarf Name (G1)
13 A1 --- m_DWD White Dwarf Component Name (G1)
15 A1 --- f_DWD [bc] Object Flag (G2)
17 I1 --- Q [1/2] Fidelity: 1=High; 2=Low
20- 23 A4 --- Tel Telescope used for spectroscopy (G3)
25- 25 I1 --- N [4/6] Number of Fitted Balmer Lines
27- 31 A5 --- SN Signal/Noise of spectra in WD fit (G4)
33- 37 I5 K Teff [6680/47800] Fit derived Surface Temperature
39- 42 I4 K e_Teff [120/2930] Uncertainty in Teff
44- 47 F4.2 [cm/s2] logg [7.3/9.1] Fit derived Log Surface Gravity
49- 52 F4.2 [cm/s2] e_logg [0.04/0.6] Uncertainty in logg
54- 56 I3 pc Dist [51/503] Fit derived Distance
58- 59 I2 pc e_Dist [2/77] Uncertainty in Distance
61- 65 F5.3 Msun MWD [0.3/1.3] Fit derived White Dwarf Mass
67- 71 F5.3 Msun e_MWD [0.02/0.3] Uncertainty in MWD
73- 76 I4 Myr tauc [2/3646] Cooling Age τc in Myr
78 A1 --- letauc Upper limit flag on e_tauc
79- 81 I3 Myr e_tauc [1/968] Uncertainty in τc
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- DWD Double White Dwarf Name (1)
14- 18 F5.3 Msun MWD1 [0.5/1.3] White Dwarf 1 Mass
20- 24 F5.3 Msun e_MWD1 [0.02/0.08] Uncertainty in MWD1
26- 30 F5.3 Msun MWD2 [0.5/1] White Dwarf 2 Mass
32- 36 F5.3 Msun e_MWD2 [0.02/0.09] Uncertainty in MWD2
38- 41 I4 Myr tauc1 [2/1670] White Dwarf 1, Cooling time τc1
43 A1 --- letauc1 Upper limit flag on e_tauc1
44- 46 I3 Myr e_tauc1 [1/320] Uncertainty in tauc1
48- 51 I4 Myr tauc2 [6/1720] White Dwarf 2, Cooling time τc2
53 A1 --- letauc2 Upper limit flag on e_tauc2
54- 56 I3 Myr e_tauc2 [1/350] Uncertainty in tauc2
58- 60 I3 pc Dist [51/506] Distance (2)
62- 63 I2 arcsec theta [2/49] Angular separation
65- 68 I4 AU Sep [385/6080] Projected binary separation
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Note (1): White Dwarfs 1 and 2 are the more and less massive WDs in the pair,
respectively.
Note (2): Computed average of the fit distance to each WD.
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- DWD Double White Dwarf Name (G1)
13 A1 --- m_DWD White Dwarf Component Name (G1)
15 A1 --- f_DWD [d-h] Object Flag (G2)
17 A1 --- Set [1-6] Category of systems with spectroscopy (1)
19- 27 A9 --- Tel Telescope used for spectroscopy (G3)
29- 29 I1 --- N [4/7]? Number of Fitted Balmer Lines
31- 36 A6 --- Type WD Type
38- 48 A11 --- SN Signal/Noise of spectra in WD fit (G4)
50- 54 I5 K Teff [6660/25200]? Fit derived Surface Temperature
56- 58 I3 K e_Teff [110/670]? Uncertainty in Teff
60- 63 F4.2 [cm/s2] logg [7.3/8.7]? Fit derived Log Surface Gravity
65- 68 F4.2 [cm/s2] e_logg [0.03/0.9]? Uncertainty in logg
70- 72 I3 pc Dist [24/472]? Fit derived Distance
74- 75 I2 pc e_Dist [1/55]? Uncertainty in Dist
77- 81 F5.3 Msun MWD [0.3/1.1]? Fit derived White Dwarf Mass
83- 87 F5.3 Msun e_MWD [0.01/0.4]? Uncertainty in Teff
89- 92 I4 Myr tauc [93/3342]? Cooling Age τc in Myr
94- 97 I4 Myr e_tauc [10/1090]? Uncertainty in tauc
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Note (1): Category of systems with spectroscopy as follows:
1 = DA/DB Systems; DB WDs in this spectroscopic sample were fit by
P. Bergeron (pers. communication)
2 = Candidate DA/DAH Systems; confirming the nature of the non-DA WDs in
these pairs requires higher S/N spectra
3 = Candidate DA/DC Systems; confirming the nature of the non-DA WDs in
these pairs requires higher S/N spectra
4 = Candidate Triple Systems
5 = Systems With Only One Spectrum
6 = Contaminants
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Global notes:
Note (G1): For previously identified systems, we label the WDs "A" and "B" as
in the literature. We order newly identified systems by their RA as
opposed to e.g., their relative brightnesses.
Note (G2): Object Flags as follows:
b = Given its anomalously low mass, PG 0901+140A may be an unresolved
triple system;
c = Despite its low mass, J1703+3304A (CDDS40-B) is unlikely to be an
unresolved double degenerate (see discussion in the Appendix), because
the discrepant distances indicate a poor fit.
d = Spectroscopic data for PG 1258+593A were taken from Gianninas et al.
(2011, J/ApJ/743/138). For a detailed discussion on this system
see Girven et al. (2010MNRAS.404..159G 2010MNRAS.404..159G)
e = J0748+3025 and J2259+1404 have already been identified as DA+DAH pairs
(Baxter et al. 2014MNRAS.440.3184B 2014MNRAS.440.3184B). J0748+3025 is composed of a
pair of WDs separated by 1.5 arcseconds. However, the SDSS spectrum
shows three cores in Hβ; see Figure 24.
f = Farihi et al. (2005, J/ApJS/161/394) identified the companion
to G 21-15 as a DC WD.
g = Silvestri et al. (2006, J/AJ/131/1674) identified J2047+0021B
as an unresolved binary composed of a carbon atmosphere WD (DQ)
with a K7 companion.
h = J2124-1620 is composed of a DA WD and an A star
Note (G3): Telescope as follows:
APO = 3.5-m telescope at Apache Point Observatory (R∼2500);
SDSS = SDSS spectrum (R∼1800),
VLT = Very Large Telescope (R∼15000) spectra from Supernova Progenitor
Survey (Koester et al. 2009, J/A+A/505/441).
Note (G4): Multiple S/N indicate multiple spectra were used in WD fits.
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History:
From electronic version of the journal
References:
Andrews et al. Paper I. 2012ApJ...757..170A 2012ApJ...757..170A
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 08-Mar-2016