J/A+A/530/A28 Priority targets for the MUCHFUSS project (Geier+, 2011)
The MUCHFUSS project - searching for hot subdwarf binaries with massive unseen
companions. Survey, target selection and atmospheric parameters.
Geier S., Hirsch H., Tillich A., Maxted P.F.L., Bentley S.J.,
Ostensen R.H., Heber U., Gaensicke B.T., Marsh T.R., Napiwotzki R.,
Barlow B.N., O'Toole S.J.
<Astron. Astrophys., 530, A28 (2011)>
=2011A&A...530A..28G 2011A&A...530A..28G
ADC_Keywords: Binaries, spectroscopic ; Stars, subdwarf ; Radial velocities
Keywords: binaries: spectroscopic - subdwarfs
Abstract:
The project Massive Unseen Companions to Hot Faint Underluminous Stars
from SDSS (MUCHFUSS) aims at finding sdBs with compact companions like
supermassive white dwarfs (M>1.0M☉), neutron stars or black
holes. The existence of such systems is predicted by binary evolution
theory and recent discoveries indicate that they are likely to exist
in our Galaxy. A determination of the orbital parameters is sufficient
to put a lower limit on the companion mass by calculating the binary
mass function. If this lower limit exceeds the Chandrasekhar mass and
no sign of a companion is visible in the spectra, the existence of a
massive compact companion is proven without the need for any
additional assumptions. We identified about 1100 hot subdwarf stars
from the SDSS by colour selection and visual inspection of their
spectra. Stars with high velocities have been reobserved and
individual SDSS spectra have been analysed. In total 127 radial
velocity variable subdwarfs have been discovered. Binaries with high
RV shifts and binaries with moderate shifts within short timespans
have the highest probability of hosting massive compact companions.
Atmospheric parameters of 69 hot subdwarfs in these binary systems
have been determined by means of a quantitative spectral analysis. The
atmospheric parameter distribution of the selected sample does not
differ from previously studied samples of hot subdwarfs. The systems
are considered the best candidates to search for massive compact
companions by follow-up time resolved spectroscopy.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 46 69 Priority targets for follow-up
table3.dat 88 17 Priority targets for follow-up (HRV subsample)
table4.dat 88 52 Priority targets for follow-up (RRV subsample)
tablea1.dat 80 89 Orbital parameters of all known hot subdwarf
binaries from literature
refs.dat 132 36 References
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See also:
J/A+A/442/1023 : Radial velocity of 17 bright subdwarf B stars (Edelmann+ 2005)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- SDSS Object name (JHHMMSS.ss+DDMMSS.s)
21- 34 A14 --- OName Other name
36- 39 F4.1 mag gmag g magnitude
41- 42 I2 --- Nsp Number of individual spectra
44- 46 I3 --- S/N S/N of the coadded spectra at ~=4100Å
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Byte-by-byte Description of file: table[34].dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- SDSS Object name (JHHMMSS.ss+DDMMSS.s)
20 A1 --- n_Class [*d] Other analysis (1)
22- 27 A6 --- Class Binary class (2)
29- 33 I5 K Teff ?=- Effective temperature
35- 38 I4 K e_Teff ? rms uncertainty on Teff
40- 43 F4.2 [cm/s2] logg ?=- Surface gravity
45- 48 F4.2 [cm/s2] e_logg ? rms uncertainty on logg
50 A1 --- l_logy Limit flag on logy
51- 55 F5.2 [-] logy ?=- Helium abundance
57- 60 F4.2 [-] e_logy ? rms uncertainty on logy
61- 64 F4.1 kpc d ?=- Heliocentric distance
66- 68 F3.1 kpc E_d ? Error on d (upper value)
70- 72 F3.1 kpc e_d ? Error on d (lower value)
74- 76 I3 km/s DRV Radial velocity shift
78- 79 I2 km/s e_DRV rms uncertainty on DRV
81- 88 F8.3 d Dt Time interval, Δt
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Note (1): Note as follows:
* = binary system analysed in Geier et al. (2011A&A...526A..39G 2011A&A...526A..39G)
d = Atmospheric parameters (Teff=39400K, logg=5.64, logy=-0.55) have
been determined by Stroer et al. (2007A&A...462..269S 2007A&A...462..269S)
Note (2): classes are sdO, sdOB, sdB/DA, sdB, He-sdO or He-sdB.
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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- 22 A22 --- Name Object name
24- 29 A6 --- n_Name Notes about the nature of the subdwarf (1)
32- 43 F12.9 d Per Period
46- 51 F6.2 km/s gamma ?=- System velocity
53- 57 F5.2 km/s e_gamma ? rms uncertainty on gamma
60- 65 F6.2 km/s K ?=- Radial velocity semi-amplitude
67- 71 F5.2 km/s e_K ? rms uncertainty on K
72 A1 --- --- [/]
73- 74 I2 km/s K2 ? Second component radial velocity semi-amplitude
76- 77 I2 km/s e_K2 ? rms uncertainty on K2
79- 80 I2 --- Ref Reference, in refs.dat file
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Note (1): Notes as follows:
p = sdB pulsators
r = binaries where with reflection effect
ec = eclipsing systems
el = systems with light variations caused by ellipsoidal deformation.
* = post-RGB stars without core helium-burning
d = double-lined binary consisting of two helium rich sdBs.
The RV semi-amplitudes of both components are given.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 43 A20 --- Aut Author's name
46-132 A87 --- Com Comments
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History:
From electronic version of the journal
References:
Geier et al., 2011A&A...526A..39G 2011A&A...526A..39G
Tillich et al., 2011A&A...527A.137T 2011A&A...527A.137T
Geier et al., 2011ApJ...731L..22G 2011ApJ...731L..22G
(End) Patricia Vannier [CDS] 30-Aug-2011