J/ApJ/898/84 Spectroscopic follow-up of 100pc WDs in SDSS & Gaia (Kilic+, 2020)
The 100pc white dwarf sample in the SDSS footprint.
Kilic M., Bergeron P., Kosakowski A., Brown W.R., Agueros M.A., Blouin S.
<Astrophys. J., 898, 84 (2020)>
=2020ApJ...898...84K 2020ApJ...898...84K
ADC_Keywords: Stars, white dwarf; Spectra, optical; Stars, masses; Abundances;
Effective temperatures; Proper motions; Parallaxes, trigonometric
Keywords: White dwarf stars; Fundamental parameters of stars;
Galaxy stellar content; Spectrophotometry; Stellar mass functions;
Stellar properties
Abstract:
We present follow-up spectroscopy of 711 white dwarfs within 100pc,
and we present a detailed model atmosphere analysis of the 100pc white
dwarf sample in the Sloan Digital Sky Survey footprint. Our
spectroscopic follow-up is complete for 83% of the white dwarfs hotter
than 6000K, where the atmospheric composition can be constrained
reliably. We identify 1508 DA white dwarfs with pure hydrogen
atmospheres. The DA mass distribution has an extremely narrow peak at
0.59M☉ and reveals a shoulder from relatively massive white
dwarfs with M=0.7-0.9M☉. Comparing this distribution with binary
population synthesis models, we find that the contribution from single
stars that form through mergers cannot explain the overabundance of
massive white dwarfs. In addition, the mass distribution of cool DAs
shows a near absence of M>1M☉ white dwarfs. The pile-up of
0.7-0.9M☉ and the disappearance of M>1M☉ white dwarfs is
consistent with the effects of core crystallization. Even though the
evolutionary models predict the location of the pile-up correctly, the
delay from the latent heat of crystallization by itself is
insufficient to create a significant pile-up, and additional cooling
delays from related effects like phase separation are necessary. We
also discuss the population of infrared-faint (ultracool) white dwarfs
and demonstrate for the first time the existence of a well-defined
sequence in color and magnitude. Curiously, this sequence is connected
to a region in the color-magnitude diagrams where the number of white
dwarfs with a helium- dominated atmosphere is low. This suggests that
the infrared-faint white dwarfs likely have mixed H/He atmospheres.
Description:
To obtain a clean 100pc white dwarf sample within the SDSS footprint,
we used the SDSS Data Release 9 (DR9) catalog matched with Gaia DR2
(see Section 2.1 and Table 1).
We obtained optical spectroscopy of 711 white dwarfs using the 1.5m
Fred Lawrence Whipple Observatory (FLWO) telescope with FAST, the MDM
Hiltner 2.4m telescope with OSMOS, the Apache Point Observatory (APO)
3.5m telescope with DIS, the 6.5m Multiple Mirror Telescope (MMT) with
the Blue Channel spectrograph and the 8m Gemini South telescope. The
observations were done between 2018 November and 2020 February.
See Section 2.2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 104 4016 The 100pc white dwarf sample in the SDSS footprint
param.dat 97 1772 Physical parameters of the white dwarfs (Tables 3-7)
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See also:
II/207 : Palomar-Green catalog UV-excess stellar objects (Green+ 1986)
III/235 : Spectroscopically Identified White Dwarfs (McCook+, 2008)
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/ApJS/133/413 : BVRIJHK photometry of cool white dwarfs (Bergeron+, 2001)
J/ApJS/156/47 : DA white dwarfs from the Palomar Green Survey (Liebert+, 2005)
J/ApJS/167/40 : SDSS4 confirmed white dwarfs catalog (Eisenstein+, 2006)
J/AJ/132/1221 : VJHK and SDSS photometry of DA white dwarfs (Holberg+, 2006)
J/AJ/131/582 : Cool white dwarfs in the SDSS (Kilic+, 2006)
J/ApJS/190/77 : Detailed analysis of cool WDs in the SDSS (Kilic+, 2010)
J/ApJ/743/138 : Spectroscopic survey of bright white dwarfs (Gianninas+, 2011)
J/ApJ/750/99 : The Pan-STARRS1 photometric system (Tonry+, 2012)
J/ApJS/204/5 : SDSS DR7 white dwarf catalog (Kleinman+, 2013)
J/MNRAS/449/3966 : Ultracool white dwarfs (Gianninas+, 2015)
J/ApJS/219/19 : Census of nearby white dwarfs from SUPERBLINK (Limoges+, 2015)
J/MNRAS/462/2295 : 25 parsec local white dwarf population (Holberg+, 2016)
J/A+A/595/A35 : Low-mass helium WDs evolutionary models (Istrate+, 2016)
J/A+A/616/A10 : 46 open clusters GaiaDR2 HR diag (Gaia Collaboration, 2018)
J/ApJ/878/63 : Cool WD atm. models. IV. Spectral evolution (Blouin+, 2019)
J/ApJ/886/100 : High-mass white dwarfs in Gaia DR2 (Cheng+, 2019)
J/ApJ/885/74 : 1340 Helium rich white dwarfs in the Gaia era (Coutu+, 2019)
J/ApJ/882/106 : DB white dwarfs with SDSS & Gaia data (Genest-Beaulieu+, 2019)
J/MNRAS/482/4570 : Gaia DR2 white dwarf candidates (Gentile Fusillo+, 2019)
J/A+A/628/A102 : Carbon-rich (DQ) white dwarfs in SDSS (Koester+, 2019)
J/ApJ/889/49 : The ELM Survey. VIII. Final double WD binaries (Brown+, 2020)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- ID Object identifier (truncated name: JHHMM+DDMM)
12- 30 I19 --- Gaia Gaia DR2 source identifier
32- 40 F9.5 deg RAdeg Gaia DR2 barycentric right ascension (ICRS)
at Ep=2015.5
42- 50 F9.5 deg DEdeg Gaia DR2 barycentric declination (ICRS) at
Ep=2015.5
52- 57 F6.2 mas plx [10/232] Gaia DR2 parallax
59- 62 F4.2 mas e_plx [0.02/1.3] Uncertainty in plx
64- 70 F7.1 mas/yr pmRA [-1093/1232] Gaia DR2 Proper motion along RA
72- 74 F3.1 mas/yr e_pmRA [0/2.4] Uncertainty in pmRA
76- 82 F7.1 mas/yr pmDE [-2712/747] Gaia DR2 Proper motion along DE
84- 86 F3.1 mas/yr e_pmDE [0.0/3.1] Uncertainty in pmDE
88- 92 F5.2 mag Gmag [12/20.6] Gaia DR2 G band apparent magnitude
94- 98 F5.2 mag BPmag [11.9/21.2] Gaia DR2 blue passband apparent
magnitude
100-104 F5.2 mag RPmag [11.9/20.3] Gaia DR2 red passband apparent
magnitude
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Byte-by-byte Description of file: param.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- ID Object identifier
(truncated name: JHHMM+DDMM)
12- 30 I19 --- Gaia Gaia DR2 source identifier
32- 39 A8 --- Type White dwarf type
41- 45 I5 K Teff [4668/53603] Effective temperature
47- 50 I4 K e_Teff [6/7768]? Uncertainty in Teff
52- 56 F5.3 [cm/s2] log(g) [6.7/9.5] Log surface gravity
58- 62 F5.3 [cm/s2] e_log(g) [0.002/0.1] Uncertainty in log (g)
64- 68 F5.3 Msun Mass [0.1/1.4] Mass
70- 74 F5.3 Msun e_Mass Uncertainty in Mass
78- 81 F4.1 [-] logH/He [-5/-1]? Log H/He abundance ratio
84- 88 F5.2 [-] logC/He [-7/-3.2]? Log C/He abundance ratio
92- 97 F6.2 [-] logCa/He [-11.3/-7.8]? Log Ca/He abundance ratio
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Acknowledgements:
Pierre Bergeron <pierre.bergeron.1 at umontreal.ca>
History:
From electronic version of the journal
(End) Prepared by [AAS], Cecile Loup [CDS], E. Perret [CDS] 28-Sep-2021