2006A&A...451..515M


C.D.S. - SIMBAD4 rel 1.7 - 2020.02.23CET00:37:43

2006A&A...451..515M - Astronomy and Astrophysics, volume 451, 515-538 (2006/5-4)

Outer structure of the Galactic warp and flare: explaining the Canis Major over-density.

MOMANY Y., ZAGGIA S., GILMORE G., PIOTTO G., CARRARO G., BEDIN L.R. and DE ANGELI F.

Abstract (from CDS):

In this paper we derive the structure of the Galactic stellar warp and flare. We use 2MASS red clump and red giant stars, selected at mean and fixed heliocentric distances of R≃3, 7 and 17kpc. Our results can be summarized as follows: (i) a clear stellar warp signature is derived for the 3 selected rings, proving that the warp starts already within the solar circle; (ii) the derived stellar warp is consistent (both in amplitude and phase-angle) with that for the Galactic interstellar dust and neutral atomic hydrogen; (iii) the consistency and regularity of the stellar-gaseous warp is traced out to about RGC∼20kpc; (iv) the Sun seems not to fall on the line of nodes. The stellar warp phase-angle orientation (φ∼15°) is close to the orientation angle of the Galactic bar and this, most importantly, produces an asymmetric warp for the inner R≃3 and 7kpc rings; (v) a Northern/Southern warp symmetry is observed only for the ring at R≃17kpc, at which the dependency on φ is weakened; (vi) treating a mixture of thin and thick disk stellar populations, we trace the variation with RGC of the disk thickness (flaring) and derive an almost constant scale-height (∼0.65kpc) within RGC∼15kpc. Further out, the disk flaring increase gradually reaching a mean scale-height of ∼1.5kpc at RGC∼23kpc; (vii) the derived outer disk warping and flaring provide further robust evidence that there is no disk radial truncation at RGC∼14kpc. In the particular case of the Canis Major (CMa) over-density we confirm its coincidence with the Southern stellar maximum warp occurring near l∼240° (for R≃7kpc) which brings down the Milky Way mid-plane by ∼3° in this direction. The regularity and consistency of the stellar, gaseous and dust warp argues strongly against a recent merger scenario for Canis Major. We present evidence to conclude that all observed parameters (e.g. number density, radial velocities, proper motion etc) of CMa are consistent with it being a normal Milky Way outer-disk population, thereby leaving no justification for more complex interpretations of its origin. The present analysis or outer disk structure does not provide a conclusive test of the structure or origin of the Monoceros Ring. Nevertheless, we show that a warped flared Milky Way contributes significantly at the locations of the Monoceros Ring. Comparison of outer Milky Way HI and CO properties with those of other galaxies favors the suggestion that complex structures close to planar in outer disks are common, and are a natural aspect of warped and flaring disks.

Abstract Copyright:

Journal keyword(s): Galaxy: structure - Galaxy: formation - galaxies: interactions - galaxies: individual: Canis Major

Simbad objects: 31

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Number of rows : 31

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 M 74 G 01 36 41.772 +15 47 00.46 10.52 10.00 9.46 9.16   ~ 1365 1
2 NGC 891 H2G 02 22 32.907 +42 20 53.95 11.08 10.81 9.93 7.86   ~ 1504 2
3 NGC 1058 Sy2 02 43 30.0247243235 +37 20 28.807743477   12.29 11.75 10.85   ~ 431 0
4 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5498 1
5 NAME Per Arm PoG 03 30 +45.0           ~ 1216 0
6 Ass Cam OB 1 As* 03 31.6 +58 38           ~ 85 0
7 NAME Tau-Aur Region SFR 04 30 +25.0           ~ 1193 1
8 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14544 1
9 NAME Ori Region reg 05 35 17.30 -05 23 28.0           ~ 470 0
10 NAME CMa Dwarf Galaxy G 07 12.6 -27 40     -0.1     ~ 186 1
11 NGC 2403 AGN 07 36 51.396 +65 36 09.17 9.31 8.84 8.38 8.19   ~ 1582 1
12 ESO 123-23 GiG 07 44 38.910 -58 09 13.18   14.97   13.75 14.0 ~ 40 0
13 NAME UMa I Galaxy G 10 34 52.80 +51 55 12.0     14.4     ~ 257 1
14 NAME UMa Region reg 11 00 +50.0           ~ 316 0
15 NAME Crux-Scutum Spiral Arm reg 12 30 -60.0           ~ 269 0
16 M 83 SBG 13 37 00.919 -29 51 56.74 8.85 8.11 7.52 7.21   ~ 2187 2
17 [NYR2002] S341+57-22.5 reg 14 10 +00.0           ~ 6 0
18 NAME Car-Sgr Arm PoG 15 00 -40.0           ~ 417 1
19 NAME Nor Arm PoG 16 00 -50.0           ~ 330 0
20 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11251 0
21 NAME SDG G 18 55 03.1 -30 28 42   4.5 3.6     ~ 1683 2
22 M 54 GlC 18 55 03.33 -30 28 47.5           ~ 873 0
23 Cl Terzan 8 GlC 19 41 44.41 -33 59 58.1     11.54     ~ 249 0
24 NGC 6946 H2G 20 34 52.332 +60 09 13.24   10.5       ~ 2203 2
25 NAME Outer Arm PoG 21 48 +69.4           ~ 212 0
26 NAME Per-Tau reg ~ ~           ~ 15 0
27 NAME Local Group GrG ~ ~           ~ 6802 0
28 NAME Norma-Cygnus Arm reg ~ ~           ~ 72 0
29 NAME Monoceros Stream St* ~ ~           ~ 308 0
30 NAME Local Arm reg ~ ~           ~ 354 0
31 NAME Gould Belt PoG ~ ~           ~ 700 1

    Equat.    Gal    SGal    Ecl

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2020.02.23-00:37:43

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