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J/ApJ/698/865          Halo streams in the SDSS-DR7             (Klement+, 2009)

Halo streams in the seventh Sloan Digital Sky Survey data release. Klement R., Rix H.-W., Flynn C., Fuchs B., Beers T.C., Allende Prieto C., Bizyaev D., Brewington H., Lee Y.S., Malanushenko E., Malanushenko V., Oravetz D., Pan K., Re Fiorentin P., Simmons A., Snedden S. <Astrophys. J., 698, 865-894 (2009)> =2009ApJ...698..865K
ADC_Keywords: Abundances, [Fe/H] ; Photometry, SDSS ; Stars, halo ; Radial velocities ; Stars, distances Keywords: Galaxy: kinematics and dynamics - solar neighborhood Abstract: We have detected stellar halo streams in the solar neighborhood using data from the seventh public data release of the Sloan Digital Sky Survey (SDSS), which includes the directed stellar program Sloan Extension For Galactic Understanding and Exploration (SEGUE). In order to derive distances to each star, we used the metallicity-dependent photometric parallax relation from Ivezic et al. (2008ApJ...684..287I). Our final sample consists of 22321 nearby (d≤2kpc), metal-poor ([Fe/H]≤-0.5) main-sequence stars with six-dimensional estimates of position and space velocity (r{vec},ν{vec}). We characterize the orbits of these stars through suitable kinematic proxies for their "effective" integrals of motion, angular momentum, eccentricity, and orbital polar angle and compare the observed distribution to expectations from a smooth distribution in four [Fe/H] bins. The metallicities provide an additional dimension in parameter space that is well suited to distinguish tidal streams from those of dynamical origin. On this basis, we identify at least five significant "phase-space overdensities" of stars on very similar orbits in the solar neighborhood to which we can assign unambiguously peaked [Fe/H] distributions. Three of them have been identified previously, including the halo stream discovered by Helmi et al. (1999MNRAS.307..495H) at a significance level of σ=12.0. In addition, we find at least two new genuine halo streams, judged by their kinematics and [Fe/H], at σ=2.9 and 4.8, respectively. Description: SDSS-I was an imaging and spectroscopic survey that began routine operations in 2000 April and continued through 2005 June. The SDSS, and its extensions, uses a dedicated 2.5m telescope located at the Apache Point Observatory in New Mexico. One of three subsurveys carried out during the first extension of the SDSS, known as SDSS-II, the Sloan Extension for Galactic Understanding and Exploration (SEGUE), ran from 2005 July to 2008 June. SEGUE obtained some 250000 medium-resolution spectra of stars in the Galaxy. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 70 7 Main characteristics of the stellar streams considered real table3.dat 102 278 Putative members of the identified streams: astrophysical parameters table4.dat 108 206 Putative members of the identified streams: photometry and velocities
See also: II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009) J/AJ/136/2070 : SEGUE stellar parameter pipeline. III. (Allende Prieto+, 2008) J/AJ/134/1579 : Halo stars in solar neighborhood (Kepley+, 2007) : Sloan Digital Sky Survey (SDSS) home page Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 4 A4 --- Stream Stream designation 6- 20 A15 --- Aut Author's reference 22- 40 A19 --- BibCode Bibcode reference 42- 45 I4 km/s Vaz Azimuthal velocity (Vaz) (1) 47- 49 I3 km/s VdelE VΔE parameter (2) 51- 53 I3 deg nu Orbital inclination (ν) 55- 58 F4.1 --- Sig Significance of the stream obtained as described in Section 6 60- 61 I2 --- N Number of putative stream members 63- 66 F4.1 [Sun] <[Fe/H]> Mean metallicity of the stream 68- 70 F3.1 [Sun] e_<[Fe/H]> <[Fe/H]> standard deviation
Note (1): The azimuthal velocity of a star is given by (U,V,W are the cartesian components of the velocity): Vaz2=(V+VLSR)2+W2 Note (2): The parameter VΔE parametrizes the difference between the energy of a star at the guiding center of its orbit and at the solar radius, and is a measure of its orbital eccentricity: VΔE2=U2+2(VLSR-Vaz)2; the eccentricity is then e=2-1/2.VΔE/VLSR
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 4 A4 --- Stream Stream designation (G1) 6- 9 A4 --- --- [SDSS] 11- 29 A19 --- SDSS SDSS name ( 31- 34 I4 --- Plate SDSS plate 35 A1 --- --- [-] 36- 40 I5 --- MJD SDSS modified Julian date 41 A1 --- --- [-] 42- 44 I3 --- Fiber SDSS fiber 46- 56 F11.7 deg RAdeg Right ascension in decimal degrees (J2000) 58- 68 F11.7 deg DEdeg Declination in decimal degrees (J2000) 70- 75 F6.3 [Sun] [Fe/H] Fe/H abundance 77- 81 F5.3 [Sun] e_[Fe/H] Fe/H uncertainty (1) 83- 86 I4 K Teff Effective temperature 88- 90 I3 K e_Teff Teff uncertainty (1) 92- 96 F5.3 [cm/s2] logg Surface gravity 98-102 F5.3 [cm/s2] e_logg logg uncertainty (1)
Note (1): The errors on [Fe/H], Teff, and logg are internal estimates, obtained from averaging of multiple techniques.
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 4 A4 --- Stream Stream designation (G1) 6- 9 A4 --- --- [SDSS] 11- 29 A19 --- SDSS SDSS name ( 31- 36 F6.3 mag umag SDSS u-band AB magnitude 38- 43 F6.3 mag gmag SDSS g-band AB magnitude 45- 50 F6.3 mag rmag SDSS r-band AB magnitude 52- 57 F6.3 mag i'mag SDSS i'-band AB magnitude 59- 64 F6.3 mag z'mag SDSS z'-band AB magnitude 66- 70 F5.3 kpc Dist Estimated distance 72- 76 F5.3 kpc e_Dist 1σ error in Dist 78- 87 F10.5 km/s HRV Heliocentric radial velocity 89- 94 F6.1 km/s U U component radial velocity (1) 96-101 F6.1 km/s V V component radial velocity 103-108 F6.1 km/s W W component radial velocity (1)
Note (1): Stars of the RAVE DR-1 stream possess high vertical and low radial velocity components, <W≥121±2km/s and <U≥24±2km/s (Paper I, Klement et al., 2008ApJ...685..261K, section 6).
Global notes: Note (G1): The last two entries in the bottom of the list are stars that appear in both "S3" and "C2", and both "S3" and "C3", respectively. The reason is that our selection criteria for "C2", "C3" and "S3" show some overlap. Also, we already noted in Section 7.4 and Section 7.6 that a connection between these streams probably exists.
History: From electronic version of the journal References: Klement et al. Paper I: Identifying stellar streams in the First RAVE Public Data Release (2008ApJ...685..261K)
(End) Emmanuelle Perret [CDS] 07-Jun-2011
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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