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J/ApJ/660/311       Hypervelocity stars. II.                 (Brown+, 2007)

Hypervelocity stars. II. The bound population. Brown W.R., Geller M.J., Kenyon S.J., Kurtz M.J., Bromley B.C. <Astrophys. J., 660, 311-318 (2007)> =2007ApJ...660..311B
ADC_Keywords: Surveys ; Galaxies, nearby ; Radial velocities ; Photometry, SDSS Keywords: Galaxy: center - Galaxy: halo - Galaxy: kinematics and dynamics - Galaxy: stellar content - stars: early-type Abstract: Hypervelocity stars (HVSs) are stars ejected completely out of the Milky Way by three-body interactions with the massive black hole in the Galactic center. We describe 643 new spectroscopic observations from our targeted survey for HVSs. We find a significant (3.5σ) excess of B-type stars with large velocities +275km/s<Vrf<450km/s and distances d>10kpc that are most plausibly explained as a new class of HVSs: stars ejected from the Galactic center on bound orbits. If a Galactic center ejection origin is correct, the distribution of HVSs on the sky should be anisotropic for a survey complete to a fixed limiting apparent magnitude. The unbound HVSs in our survey have a marginally anisotropic distribution on the sky, consistent with the Galactic center ejection picture. Description: Brown et al. (2006, Cat. J/ApJ/647/303) describe our target selection for candidate HVSs. We have also carried out a new, complementary HVS survey targeting bright stars with and B-type colors in the SDSS. We use the 1.5m Tillinghast telescope and the FAST spectrograph to observe these bright HVS candidates. New observations at the 6.5m MMT telescope were obtained with the Blue Channel Spectrograph on the nights of 2006 May 23-26 and 2006 June 19-20. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 49 11 Possible found High-Velocity Stars. table2.dat 71 643 *HVS Survey: new observations
Note on table2.dat: Stars identified as [BGK2006] in Simbad
See also: J/ApJ/647/303 : Spectroscopic survey of hypervelocity stars (Brown+, 2006) J/ApJ/671/1708 : Hypervelocity stars. III (Brown+, 2007) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 4 A4 --- --- [SDSS] 6- 24 A19 --- SDSS SDSS name ( 26- 30 F5.1 deg Glon Galactic longitude 31- 35 F5.1 deg Glat Galactic latitude 37- 40 I4 km/s Vrf Rest-frame (galactocentric) velocity 42- 43 A2 --- Sp Spectral type 45- 46 I2 kpc Ra Galactocentric distance assuming a MS star (main-sequence) 48- 49 I2 kpc Rb Galactocentric distance assuming a BHB star (blue horizontal branch)
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 2 I2 h RAh Hour of Right Ascension (J2000) 4- 5 I2 min RAm Minute of Right Ascension (J2000) 7- 11 F5.2 s RAs Second of Right Ascension (J2000) 13 A1 --- DE- Sign of the Declination (J2000) 14- 15 I2 deg DEd Degree of Declination (J2000) 17- 18 I2 arcmin DEm Arcminute of Declination (J2000) 20- 23 F4.1 arcsec DEs Arcsecond of Declination (J2000) 25- 30 F6.3 mag g'mag Apparent g' band magnitude 32- 36 F5.3 mag e_g'mag Uncertainty in gmag 38- 42 F5.3 mag (u'-g')0 Intrinsic (u'-g') color 44- 48 F5.3 mag e_(u'-g')0 Uncertainty in (u-g)0 50- 55 F6.3 mag (g'-r')0 Intrinsic (g'-r') color 57- 61 F5.3 mag e_(g'-r')0 Uncertainty in (g-r)0 63 I1 --- WD [0/1] code 1=White dwarf, 0=B-type star 65- 68 I4 km/s HV Heliocentric velocity 70- 71 I2 km/s e_HV Uncertainty in HV
History: * 08-Sep-2008: From electronic version of the journal * 01-Nov-2008: one typo corrected in table2 (declination sign)
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 08-Sep-2008
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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