J/ApJ/588/824 Velocities of blue stars near (l,b)=(198,-27) (Yanny+, 2003)
A low-latitude halo stream around the Milky way.
Yanny B., Newberg H.J., Grebel E.K., Kent S., Odenkirchen M., Rockosi C.M.,
Schlegel D., Subbarao M., Brinkmann J., Fukugita M., Ivezic Z., Lamb D.Q.,
Schneider D.P., York D.G.
<Astrophys. J. 588, 824 (2003)>
=2003ApJ...588..824Y 2003ApJ...588..824Y
ADC_Keywords: Stars, halo ; Stars, blue ; Radial velocities ; Photometry, SDSS
Keywords: Galaxy: halo - Galaxy: structure
Abstract:
We present evidence for a ring of stars in the plane of the Milky Way,
extending at least from l=180° to 227° with turnoff magnitude
g∼19.5; the ring could encircle the Galaxy. We infer that the low
Galactic latitude structure is at a fairly constant distance of
R=18±2kpc from the Galactic center above the Galactic plane and has
R=20±2kpc in the region sampled below the Galactic plane. The
evidence includes 500 Sloan Digital Sky Survey spectroscopic radial
velocities of stars within 30° of the plane. The velocity
dispersion of the stars associated with this structure is found to be
27km/s at (l, b)=(198, -27), 22km/s at (l, b)=(225, 28),
30km/s at (l, b)=(188, 24), and 30km/s at (l, b)=(182, 27). The
structure rotates in the same prograde direction as the Galactic disk
stars but with a circular velocity of 110±25km/s. The narrow
measured velocity dispersion is inconsistent with power-law spheroid
or thick-disk populations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 95 392 Blue stars near (l,b) = (198°, -27°)
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See also:
http://www.sdss.org/ : SDSS Home Page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 F9.6 deg RAdeg Right Ascension in decimal degrees (J2000)
12- 20 F9.6 deg DEdeg Declination in decimal degrees (J2000)
22- 38 A17 --- SDSS-ID Identification in SDSS (1)
40- 52 A13 --- FID Fiber identification (2)
54- 59 F6.3 mag gmag The SDSS g band magnitude (3)
61- 66 F6.3 mag g-r ? The SDSS (g-r) color index (3)
69- 73 F5.3 mag u-g ? The SDSS (u-g) color index (3)
75- 80 F6.1 km/s HRV Heliocentric corrected radial velocity
82- 86 F5.2 0.1nm EWCaII Ca II K absorption line equivalent width in
units of Angstroems
88 I1 --- CCut [0,1] Color cut in F-star box (4)
90- 95 F6.4 mag E(B-V) The (B-V) excess at (RAdeg,DEdeg) (5)
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Note (1): In the format of run-rerun-camcol-field-id.
[YNG2003] NNNN-N-N-NNN-NNNN in Simbad
Note (2): In the format of plate-MJD-fiber.
Note (3): Reddening corrected
Note (4): Colour cut is 1 when the star is in the F-star box:
0.158<g-r<0.3, 19.1<gmag<20.3;
0 = outside box.
Note (5): From Schlegel, Finkbeiner and Davis (1998ApJ...500..525S 1998ApJ...500..525S).
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Table 2: Summary of Stream Detection Pieces
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[YNG2003] RA DE l b sigma g0 (g-r)0 Vcirc
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Sp198-27-19.8 72 0 198 -27 74 ± 5 27 19.8 0.24 -5 ± 54
Sp225+28-19.6 133 2 225 28 103 ± 6 23 19.6 0.26 139 ± 27
Sp182+27-19.4 117 38 182 27 22 ± 8 30 19.4 0.28
Sp188+24-19.3 115 32 188 24 34 ± 7 30 19.3 0.28 12 ± 200
Sag. south stream 35 0 165 -55 -111 ± 5 20 21.5 0.22
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Notes: Objects are identified as [YNG2003] SpLLL+BB-NN.N in Simbad
g0 and (g-r)0 are Magnitude and color of faint blue Monoceros
turnoff except where indicated.
Sp198-27-19.8 is from plate 797.
For the Sagittarius stream, and sigma refer to Sagittarius stream
blue horizontal branch and blue straggler stars rather than those in
the Monoceros structures. The color and magnitude are those of the
Sagittarius stream.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 31-Jul-2003