J/AJ/123/2511 RV photometry of Draco dwarf spheroidal galaxy (Piatek+, 2002)
Structure of the Draco dwarf spheroidal galaxy.
Piatek S., Pryor C., Armandroff T.E., Olszewski E.W.
<Astron. J. 123, 2511 (2002)>
=2002AJ....123.2511P 2002AJ....123.2511P
ADC_Keywords: Galaxies, photometry ; Photometry, CCD
Keywords: galaxies: dwarf - galaxies: individual (Draco) -
galaxies: stellar content - galaxies: structure - Local Group
Abstract:
This article studies the structure of the Draco dwarf spheroidal
galaxy, with an emphasis on the question of whether the spatial
distribution of its stars has been affected by the tidal interaction
with the Milky Way, using R- and V-band CCD photometry for 11 fields
that are located in and around the Draco galaxy. 9 fields are in
common with Piatek et al. (J/AJ/121/841); two additional fields, N1
and S1, are adjacent to the central C0 field studied by Piatek et al.
in the north and south dire ctions, respectively, and extend beyond
the tidal boundary along the minor axis. hese additional fields were
imaged with the KPNO 0.9 m telescope using the 2048x2048 T2KA CCD chip.
The article reports coordinates for the center, a position angle of
the major axis, and the ellipticity. It also reports the results of
searches for asymmetries in the structure of Draco. These results and
searches for a "break" in the radial profile and for the presence of
principal sequences of Draco in a color-magnitude diagram for regions
more than 50' from the center yield no evidence that tidal forces from
the Milky Way have affected the structure of Draco.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 94 6843 R and V Photometry of Draco: N1 field (table 2a)
table3.dat 94 8176 R and V Photometry of Draco: S1 field (table 2b)
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See also:
J/AJ/110/2131 : M/L for Draco and UMi. I. (Armandroff+ 1995)
J/MNRAS/330/792 : Radial velocity in Draco (Kleyna+, 2002)
J/AJ/121/841 : Draco dwarf spheroidal galaxy RV photometry (Piatek+, 2001)
Byte-by-byte Description of file: table2.dat table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- [PPA2001] Star identification number (1)
6- 13 F8.3 pix Xpix The X pixel coordinate
15- 22 F8.3 pix Ypix The Y pixel coordinate
24- 25 I2 h RAh Hour of Right Ascension (J2000) (2)
27- 28 I2 min RAm Minute of Right Ascension (J2000) (2)
30- 34 F5.2 s RAs Second of Right Ascension (J2000) (2)
35 A1 --- DE- Sign of Declination (J2000) (2)
36- 37 I2 deg DEd Degree of Declination (J2000) (2)
39- 40 I2 arcmin DEm Arcminute of Declination (J2000) (2)
42- 46 F5.2 arcsec DEs Arcsecond of Declination (J2000) (2)
48- 54 F7.4 mag Rmag The R band magnitude
56- 61 F6.4 mag e_Rmag The uncertainty in Rmag
63- 69 F7.4 mag Vmag The V band magnitude
71- 76 F6.4 mag e_Vmag The uncertainty in Vmag
78- 84 F7.4 --- CHI The average CHI fit value (3)
86- 93 F8.4 --- SHARP The average SHARP classification value (4)
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Note (1): Simbad nomenclature:
[PPA2001] N1 NNNN in table2, [PPA2001] S1 NNNN in table3
Note (2): The equatorial coordinates come from plate solutions based on
positions for stars in the USNO-A2.0 catalog (Monet et al., 1998,
Cat. I/252) using a recipe developed by Paul Harding (priv. comm.).
Note (3): A measure of the quality of the point-spread function fit from
DAOPHOT.
Note (4): A large positive value of the SHARP index calculated by the
DAOPHOT package indicates an object that is more extended than the
point-spread function - which is likely a galaxy.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 17-Jun-2002