J/ApJ/684/1143 BHB candidates in the Milky Way (Xue+, 2008)
The Milky Way's circular velocity curve to 60 kpc and an estimate of the dark
matter halo mass from the kinematics of ∼2400 SDSS blue horizontal-branch stars.
Xue X.X., Rix H.W., Zhao G., Re Fiorentin P., Naab T., Steinmetz M.,
van den Bosch F.C., Beers T.C., Lee Y.S., Bell E.F., Rockosi C., Yanny B.,
Newberg H., Wilhelm R., Kang X., Smith M.C., Schneider D.P.
<Astrophys. J., 684, 1143-1158 (2008)>
=2008ApJ...684.1143X 2008ApJ...684.1143X
ADC_Keywords: Milky Way ; Photometry, ugriz ; Radial velocities ;
Stars, horizontal branch ; Abundances, [Fe/H]
Keywords: dark matter - galaxies: individual (Milky Way) - Galaxy: halo -
stars: horizontal-branch - stars: kinematics
Abstract:
We derive new constraints on the mass of the Milky Way's dark matter
halo, based on 2401 rigorously selected blue horizontal-branch halo
stars from SDSS DR6. This sample enables construction of the full
line-of-sight velocity distribution at different galactocentric radii.
To interpret these distributions, we compare them to matched mock
observations drawn from two different cosmological galaxy formation
simulations designed to resemble the Milky Way. This procedure results
in an estimate of the Milky Way's circular velocity curve to ∼60kpc,
which is found to be slightly falling from the adopted value of
220km/s at the Sun's location, and implies
M(<60kpc)=(4.0±0.7)x1011M☉.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 282 10224 List of 10224 BHB candidates selected by color cut
table2.dat 280 2558 List of 2558 BHB stars selected from SDSS DR6
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See also:
J/A+A/522/A88 : Photometric identification of BHB stars (Smith+, 2010)
J/AJ/130/1097 : BHB stars in Century Survey Galactic Halo Project (Brown+,
2005)
J/other/Sci/292.698 : Candidate halo dark matter (Oppenheimer+, 2001)
http://www.sdss.org/ : SDSS web page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- SpID Spectrum name (MJD-Plate-Fiber)
20- 23 A4 --- --- [SDSS]
24- 42 A19 --- SDSS SDSS-DR6 Name (JHHMMSS.ss+DDMMSS.s) (1)
48- 57 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
63- 72 F10.6 deg DEdeg Declination in decimal degrees (J2000)
78- 87 F10.6 deg GLON Galactic Longitude
93-102 F10.6 deg GLAT Galactic Latitude
106-110 F5.2 mag gmag Extinction-corrected g band magnitude
114-118 F5.2 mag g-r The g-r color index after extinction correction
123-126 F4.2 mag u-g The u-g color index after extinction correction
131-134 F4.2 mag e_umag Error of u band magnitude
138-142 F5.2 mag e_gmag Error of g band magnitude
147-150 F4.2 mag e_rmag Error of r band magnitude
160-165 F6.1 km/s HRV Heliocentic radial velocity
176-180 F5.1 km/s e_HRV Error in HRV
190-195 F6.1 km/s RVgal Galactocentric radial velocity (2)
211-215 F5.2 --- fm ?=-9.99 Flux of Hδ line relative to the
continuum at the line core
224-235 F12.2 0.1nm D0.2 ?=-9.99 Width of Hδ line at 20% below the
local continuum
248-255 F8.2 --- cgam ?=-9.99 The c of Hγ line (G1)
267-275 F9.2 0.1nm bgam ?=-9.99 The b of Hγ line in Angstroms (G1)
280-282 A3 --- Type Object type: BHB, BS or MS (3)
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Note (1): This sample contains some repeated stars.
Note (2): Adopting solar motion (10.0,5.2,7.2)km/s and local rotation of 220km/s
Note (3): Type is classified only by D0.2 & fm method, as;
BHB = Blue Horizontal Branch;
BS = Blue Straggler;
MS = Main Sequence.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- SpID Spectrum name (MJD-Plate-Fiber)
20- 23 A4 --- --- [SDSS]
24- 42 A19 --- SDSS SDSS-DR6 Name (JHHMMSS.ss+DDMMSS.s)
53- 62 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
73- 82 F10.6 deg DEdeg Declination in decimal degrees (J2000)
93-102 F10.6 deg GLON Galactic Longitude
113-122 F10.6 deg GLAT Galactic Latitude
126-130 F5.2 mag gmag Extinction-corrected g band magnitude
135-138 F4.2 mag u-g The u-g color index after extinction correction
142-146 F5.2 mag g-r The g-r color index after extinction correction
151-154 F4.2 mag gMAG Absolute g band magnitude
158-162 F5.2 0.1nm D0.2 Width of Hδ line, in Angstroms, at 20%
below the local continuum
167-170 F4.2 --- fm Flux of Hδ line relative to the
continuum at the line core
175-178 F4.2 --- cgam The c of Hγ line (G1)
182-186 F5.2 0.1nm bgam The b of Hγ line in Angstroms (G1)
191-194 F4.1 kpc Dist Distance to the Sun
199-202 F4.1 kpc r Distance to the Galactic center
206-210 F5.1 kpc x The x galactocentric coordinate (toward Sun)
214-218 F5.1 kpc y The y galactocentric coordinate
(direction of rotation)
222-226 F5.1 kpc z The z galactocentric coordinate (toward NGP)
229-234 F6.1 km.s-1 HRV Heliocentic radial velocity
237-242 F6.1 km.s-1 e_HRV Error in HRV
245-250 F6.1 km.s-1 Vgal Galactocentric radial velocity (1)
253-258 I6 K Teff ?=-9999 Effective temperature by Ron Wilhelm
262-266 F5.2 [cm/s2] logg ?=-9.99 Surface gravity by Ron Wilhelm
270-274 F5.2 [-] FeH ?=-9.99 Metallicity by Ron Wilhelm
278-280 A3 --- Type [BHB] Source type (Blue Horizontal Branch) (2)
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Note (1): Adopting solar motion (10.0,5.2,7.2)km/s and local rotation of 220km/s
Note (2): BHB stars are classified by combination of D0.2 & fm method and the
scale width vs shape method.
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Global notes:
Note (G1): b and c free parameters used in the equation (2) (section 2.1.2):
y=n-a.exp[-(|λ-λ0|/b)c]
where y is the normalized flux density and λ0 is assumed to
be the nominal wavelength of the Balmer line.
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 10-Dec-2010