J/MNRAS/457/1988 White dwarfs in Galactic plane (Raddi+, 2016)
A search for white dwarfs in the Galactic plane: the field and the open
cluster population.
Raddi R., Catalan S., Gansicke B.T., Hermes J.J., Napiwotzki R.,
Koester D., Tremblay P.-E., Barentsen G., Farnhill H.J., Mohr-Smith M.,
Drew J.E., Groot P.J., Guzman-Ramirez L., Parker Q.A., Steeghs D.,
Zijlstra A.
<Mon. Not. R. Astron. Soc., 457, 1988-2004 (2016)>
=2016MNRAS.457.1988R 2016MNRAS.457.1988R (SIMBAD/NED BibCode)
ADC_Keywords: Galactic plane ; Stars, white dwarf ; Photometry ; Stars, ages ;
Stars, masses
Keywords: stars: AGB and post-AGB - stars: mass-loss - stars: neutron -
white dwarfs - open clusters and associations: general
Abstract:
We investigated the prospects for systematic searches of white dwarfs
at low Galactic latitudes, using the VLT Survey Telescope Hα
Photometric Survey of the Galactic plane and Bulge (VPHAS+). We
targeted 17 white dwarf candidates along sightlines of known open
clusters, aiming to identify potential cluster members. We confirmed
all the 17 white dwarf candidates from blue/optical spectroscopy, and
we suggest five of them to be likely cluster members. We estimated
progenitor ages and masses for the candidate cluster members, and
compare our findings to those for other cluster white dwarfs. A white
dwarf in NGC 3532 is the most massive known cluster member
(1.13M☉), likely with an oxygen-neon core, for which we
estimate an M☉ progenitor, close to the mass-divide between
white dwarf and neutron star progenitors. A cluster member in Ruprecht
131 is a magnetic white dwarf, whose progenitor mass exceeded
2-3M☉. We stress that wider searches, and improved cluster
distances and ages derived from data of the ESA Gaia mission, will
advance the understanding of the mass-loss processes for low- to
intermediate-mass stars.
Description:
Here, we use the primary detections of the VPHAS+ data release 2
(DR2) (Drew et al., 2014, Cat. II/341), accessible through the ESO
Science Archive. It delivers PSF magnitudes, expressed in the Vega
system, for 24 per cent of the survey area.
We acquired optical spectroscopy for 17 white dwarf candidates on 2014
April 28-30 with the visual and near-UV FOcal Reducer and low
dispersion Spectrograph (FORS2), mounted on the Very Large Telescope
(VLT) UT1 (Antu).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 128 17 Details for the 17 white dwarf candidates
confirmed by this study
table3.dat 68 3 Johnson-Kron-Cousins for the three white dwarfs
in NGC 3532 (Clem et al. 2011, Cat. J/AJ/141/115)
table4.dat 135 17 Physical parameters of the 17 white dwarfs
confirmed via spectroscopic follow-up
table5.dat 94 5 *Physical parameters of the white dwarf progenitors
for the five likely cluster members
tablea1.dat 181 36 g-band absolute magnitudes and colours of DA
white dwarfs in the VPHAS+ Vega system
tablea2.dat 181 18 g-band absolute magnitudes and colours of DB
white dwarfs in the VPHAS+ Vega system
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Note on table5.dat: determined via interpolation of the progenitor ages with the
BaSTI and Ekstroem et al. (2012, Cat. J/A+A/537/A146) isochrones for
rotating stars.
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See also:
II/341 : VPHAS+ DR2 survey (Drew+, 2016)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- --- [VPHAS]
7- 24 A18 --- VPHAS VPHAS name (JHHMMSS.s+DDMMSS.s)
26- 30 F5.2 mag umag u magnitude
32- 35 F4.2 mag e_umag rms uncertainty on umag
37- 41 F5.2 mag gmag g magnitude
43- 46 F4.2 mag e_gmag rms uncertainty on gmag
48- 52 F5.2 mag rbmag r blue frame magnitude
54- 57 F4.2 mag e_rbmag rms uncertainty on rbmag
59- 63 F5.2 mag rrmag r red frame magnitude
65- 68 F4.2 mag e_rrmag rms uncertainty on rrmag
70- 74 F5.2 mag Hamag ?=- Hα magnitude
76- 79 F4.2 mag e_Hamag ? rms uncertainty on Hamag
81- 85 F5.2 mag imag ?=- i magnitude
87- 90 F4.2 mag e_imag ? rms uncertainty on imag
92- 95 I4 --- Field Field number
97-106 A10 --- Obs.dateb Observation date for blue (ugr) frame
108-117 A10 --- Obs.dater Observation date for red (rHai) frame
119-128 A10 --- Name Short VPHAS name (JHHMM+DDMM)
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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- 5 A5 --- --- [VPHAS]
7- 16 A10 --- Name Short VPHAS name (JHHMM+DDMM)
18- 23 F6.3 mag Bmag Johnson B magnitude
25- 29 F5.3 mag e_Bmag rms uncertainty on Bmag
31- 36 F6.3 mag Vmag Johnson V magnitude
38- 42 F5.3 mag e_Vmag rms uncertainty on Vmag
44- 49 F6.3 mag Rcmag Cousins R magnitude
51- 55 F5.3 mag e_Rcmag rms uncertainty on Rcmag
57- 62 F6.3 mag Icmag Cousins I magnitude
64- 68 F5.3 mag e_Icmag rms uncertainty on Icmag
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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- 5 A5 --- --- [VPHAS]
7- 16 A10 --- Name Short VPHAS name (JHHMM+DDMM)
18- 29 A12 --- Cluster Cluster name
31- 32 I2 --- S/N Signal-to-noise ratio measured at Hβ
34- 36 A3 --- Type White dwarf type
39 A1 --- n_Teff [a] Note on Teff (1)
41- 45 I5 K Teff Effective temperature
47- 50 I4 K e_Teff rms uncertainty on Teff
52- 55 F4.2 [cm/s2] logg Surface gravity
57- 60 F4.2 [cm/s2] e_logg rms uncertainty on logg
62- 66 F5.2 mag gMAG Absolute g magnitude
68- 71 F4.2 mag E_gMAG Error on gMAG (upper value)
73- 76 F4.2 mag e_gMAG Error on gMAG (lower value)
78- 81 F4.2 mag E(B-V) ?=- Redenning
83- 86 F4.2 mag e_E(B-V) ? rms uncertainty on E(B-V)
88- 91 I4 pc Dist Distance
93- 95 I3 pc e_Dist rms uncertainty on Dist
97-100 F4.2 Msun Mass WD mass
102-105 F4.2 Msun E_Mass Error on Mass (upper value)
107-110 F4.2 Msun e_Mass Error on Mass (lower value)
112 A1 --- n_tau [b] Note on tau (1)
113-117 F5.3 Gyr tau WD age
119-123 F5.3 Gyr E_tau ? Error on tau (upper value)
125-129 F5.3 Gyr e_tau ? Error on tau (lower value)
131-135 F5.2 --- dtau ? Fractional difference in cooling ages,
between Montreal and BaSTI models
(see Section 4.1 for details)
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Note (1): Notes as follows:
a = Effective temperatures of DAH and DC white dwarfs are estimated from
photometric fitting; no E(B-V) estimates
b = Cooling age determined from Althaus et al. (2007, Cat. J/A+A/465/249)
oxygen-neon core models
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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- 5 A5 --- --- [VPHAS]
7- 16 A10 --- Name Short VPHAS name (JHHMM+DDMM)
18- 29 A12 --- Cluster Cluster name
31- 34 F4.2 Msun MWWD Mass of the white dwarf progenitor
36- 39 F4.2 Msun E_MWWD Error on MWWD (upper value)
41- 44 F4.2 Msun e_MWWD Error on MWWD (lower value)
46- 50 F5.3 Gyr tprog Age of the progenitor
52- 56 F5.3 Gyr E_tprog Error on tprog (upper value)
58- 62 F5.3 Gyr e_tprog ? Error on tprog (lower value)
64 A1 --- l_MprogB Limit flag on MprogB
65- 68 F4.2 Msun MprogB BatSI mass of the progenitor
70- 73 F4.2 Msun E_MprogB ? Error on MprogB (upper value)
75- 78 F4.2 Msun e_MprogB Error on MprogB (lower value)
80 A1 --- l_Mprogr Limit flag on Mprogr
81- 84 F4.2 Msun Mprogr Rotational mass of the progenitor
86- 89 F4.2 Msun E_Mprogr ? Error on Mprogr (upper value)
91- 94 F4.2 Msun e_Mprogr Error on Mprogr (lower value)
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Byte-by-byte Description of file: tablea1.dat tablea2.dat
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Bytes Format Units Label Explanations
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1- 6 I6 K Teff Effective temperature
8- 13 F6.3 mag gMAG7.0 Absolute g magnitude for logg=7.00
15- 20 F6.3 mag (u-g)7.0 Absolute u-g colour index for logg=7.00
22- 27 F6.3 mag (g-r)7.0 Absolute g-r colour index for logg=7.00
29- 34 F6.3 mag (r-i)7.0 Absolute r-i colour index for logg=7.00
36- 41 F6.3 mag (r-Ha)7.0 Absolute r-Ha colour index for logg=7.00
43- 48 F6.3 mag gMAG7.5 Absolute g magnitude for logg=7.50
50- 55 F6.3 mag (u-g)7.5 Absolute u-g colour index for logg=7.50
57- 62 F6.3 mag (g-r)7.5 Absolute g-r colour index for logg=7.50
64- 69 F6.3 mag (r-i)7.5 Absolute r-i colour index for logg=7.50
71- 76 F6.3 mag (r-Ha)7.5 Absolute r-Ha colour index for logg=7.50
78- 83 F6.3 mag gMAG8.0 Absolute g magnitude for logg=8.00
85- 90 F6.3 mag (u-g)8.0 Absolute u-g colour index for logg=8.00
92- 97 F6.3 mag (g-r)8.0 Absolute g-r colour index for logg=8.00
99-104 F6.3 mag (r-i)8.0 Absolute r-i colour index for logg=8.00
106-111 F6.3 mag (r-Ha)8.0 Absolute r-Ha colour index for logg=8.00
113-118 F6.3 mag gMAG8.5 Absolute g magnitude for logg=8.50
120-125 F6.3 mag (u-g)8.5 Absolute u-g colour index for logg=8.50
127-132 F6.3 mag (g-r)8.5 Absolute g-r colour index for logg=8.50
134-139 F6.3 mag (r-i)8.5 Absolute r-i colour index for logg=8.50
141-146 F6.3 mag (r-Ha)8.5 Absolute r-Ha colour index for logg=8.50
148-153 F6.3 mag gMAG9.0 Absolute g magnitude for logg=9.00
155-160 F6.3 mag (u-g)9.0 Absolute u-g colour index for logg=9.00
162-167 F6.3 mag (g-r)9.0 Absolute g-r colour index for logg=9.00
169-174 F6.3 mag (r-i)9.0 Absolute r-i colour index for logg=9.00
176-181 F6.3 mag (r-Ha)9.0 Absolute r-Ha colour index for logg=9.00
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 20-Mar-2017