First glimpse results on the stellar structure of the galaxy

被引:330
作者
Benjamin, RA
Churchwell, E
Babler, BL
Indebetouw, R
Meade, MR
Whitney, BA
Watson, C
Wolfire, MG
Wolff, MJ
Ignace, R
Bania, TM
Bracker, S
Clemens, DP
Chomiuk, L
Cohen, M
Dickey, JM
Jackson, JM
Kobulnicky, HA
Mercer, EP
Mathis, JS
Stolovy, SR
Uzpen, B
机构
[1] Univ Wisconsin, Dept Phys, Whitewater, WI 53190 USA
[2] Univ Wisconsin, Dept Astron, Madison, WI 53706 USA
[3] Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA
[4] Space Sci Inst, Boulder, CO 80301 USA
[5] Manchester Coll, Dept Phys, N Manchester, IN 46962 USA
[6] Univ Maryland, Dept Astron, College Pk, MD 20742 USA
[7] E Tennessee State Univ, Dept Phys Astron & Geol, Johnson City, TN 37614 USA
[8] Boston Univ, Inst Astrophys Res, Boston, MA 02215 USA
[9] Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA
[10] Univ Tasmania, Sch Math & Phys, Hobart, Tas 7001, Australia
[11] Univ Wyoming, Dept Phys & Astron, Laramie, WY 82072 USA
[12] CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA
关键词
Galaxy : stellar content; Galaxy : structure; infrared : general; infrared : ISM; infrared : stars; ISM : general; stars : general; surveys;
D O I
10.1086/491785
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
The GLIMPSE ( Galactic Legacy Mid-Plane Survey Extraordinaire) Point Source Catalog of similar to 30 million mid-infrared sources toward the inner Galaxy, 10 degrees <= vertical bar l vertical bar <= 65 degrees and vertical bar b vertical bar <= 1 degrees, was used to determine the distribution of stars in Galactic longitude, l, latitude, b, and apparent magnitude, m. The counts versus longitude can be approximated by the modified Bessel function N = N-0(l/l(0)) K-1(l/l(0)), where l(0) is insensitive to limiting magnitude, band choice, and side of Galactic center: l(0) = 17 degrees - 30 degrees with a best-fit value in the 4.5 mu m band of l(0) = 24 degrees +/- 4 degrees. Modeling the source distribution as an exponential disk yields a radial scale length of H-* = 3.9 +/- 0.6 kpc. There is a pronounced north-south asymmetry in source counts for vertical bar l vertical bar <= 30 degrees, with similar to 25% more stars in the north. For l = 10 degrees - 30 degrees, there is a strong enhancement of stars of m = 11.5 - 13.5 mag. A linear bar passing through the Galactic center with half-length R-bar = 4.4 +/- 0.5 kpc, tilted by phi 44 degrees +/- 10 degrees to the Sun-Galactic center line, provides the simplest interpretation of these data. We examine the possibility that enhanced source counts at l p 26 degrees - 28 degrees, 31 degrees.5 - 34 degrees, and 306 degrees - 309 degrees are related to Galactic spiral structure. Total source counts are depressed in regions where the counts of red objects (m(K) - m([8.0]) > 3) peak. In these areas, the counts are reduced by extinction due to molecular gas, high diffuse backgrounds associated with star formation, or both.
引用
收藏
页码:L149 / L152
页数:4
相关论文
共 19 条
[1]  
Altenhoff W. J., 1970, ASTRON ASTROPHYS S, V1, P319
[2]  
[Anonymous], EXPLANATORY SUPPLEME
[3]   GLIMPSE.: I.: An SIRTF legacy project to map the inner galaxy [J].
Benjamin, RA ;
Churchwell, E ;
Babler, BL ;
Bania, TM ;
Clemens, DP ;
Cohen, M ;
Dickey, JM ;
Indebetouw, R ;
Jackson, JM ;
Kobulnicky, HA ;
Lazarian, A ;
Marston, AP ;
Mathis, JS ;
Meade, MR ;
Seager, S ;
Stolovy, SR ;
Watson, C ;
Whitney, BA ;
Wolff, MJ ;
Wolfire, MG .
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC, 2003, 115 (810) :953-964
[4]   THE RELATIONSHIP BETWEEN INFRARED, OPTICAL, AND ULTRAVIOLET EXTINCTION [J].
CARDELLI, JA ;
CLAYTON, GC ;
MATHIS, JS .
ASTROPHYSICAL JOURNAL, 1989, 345 (01) :245-256
[5]  
Churchwell E, 2005, GLIMPSE QUALITY ASSU
[6]   A MODEL OF THE 2-35-MU-M POINT-SOURCE INFRARED SKY [J].
COHEN, M .
ASTRONOMICAL JOURNAL, 1993, 105 (05) :1860-1879
[7]   Gas dynamics and large-scale morphology of the Milky Way galaxy [J].
Englmaier, P ;
Gerhard, O .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1999, 304 (03) :512-534
[8]   The Infrared Array Camera (IRAC) for the Spitzer Space Telescope [J].
Fazio, GG ;
Hora, JL ;
Allen, LE ;
Ashby, MLN ;
Barmby, P ;
Deutsch, LK ;
Huang, JS ;
Kleiner, S ;
Marengo, M ;
Megeath, ST ;
Melnick, GJ ;
Pahre, MA ;
Patten, BM ;
Polizotti, J ;
Smith, HA ;
Taylor, RS ;
Wang, Z ;
Willner, SP ;
Hoffmann, WF ;
Pipher, JL ;
Forrest, WJ ;
McMurty, CW ;
McCreight, CR ;
McKelvey, ME ;
McMurray, RE ;
Koch, DG ;
Moseley, SH ;
Arendt, RG ;
Mentzell, JE ;
Marx, CT ;
Losch, P ;
Mayman, P ;
Eichhorn, W ;
Krebs, D ;
Jhabvala, M ;
Gezari, DY ;
Fixsen, DJ ;
Flores, J ;
Shakoorzadeh, K ;
Jungo, R ;
Hakun, C ;
Workman, L ;
Karpati, G ;
Kichak, R ;
Whitley, R ;
Mann, S ;
Tollestrup, EV ;
Eisenhardt, P ;
Stern, D ;
Gorjian, V .
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 2004, 154 (01) :10-17
[9]   A COBE model of the galactic bar and disk [J].
Freudenreich, HT .
ASTROPHYSICAL JOURNAL, 1998, 492 (02) :495-510
[10]  
Gerhard O, 2002, ASTR SOC P, V273, P73