The spiral structure of the Galaxy revealed by CS sources and evidence for the 4:1 resonance

Lépine, J. R. D.; Roman-Lopes, Alexandre; Abraham, Z.; Junqueira, Thiago C.; Mishurov, Yu. N.

doi:10.1111/j.1365-2966.2011.18492.x

Cited by 40 publications

(57 citation statements)

References 57 publications

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“…There is no consensus on the number, pitch angle, and shape of Galactic spiral arms (Vallée 2005;Hou et al 2009;Lépine et al 2011;Siebert et al 2012;Francis & Anderson 2012;Vallée 2014a,b;Griv et al 2014;Bobylev 2014;Pettitt et al 2014). The Sun's location within the dust obscured Galactic disc is a complicating factor to observe the Galactic structure.…”

Section: Introductionmentioning

confidence: 99%

Tracing the Galactic spiral structure with embedded clusters

Camargo

Bonatto

Bica

2015

Monthly Notices of the Royal Astronomical Society

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In the present work we investigate the properties of 18 embedded clusters (ECs). The sample includes 11 previously known clusters and we report the discovery of 7 ECs on WISE images, thus complementing our recent list of 437 new clusters. The main goal is to use such clusters to shed new light on the Galactic structure by tracing the spiral arms with cluster distances. Our results favour a four-armed spiral pattern tracing three arms, Sagitarius-Carina, Perseus, and the Outer arm. The SagitariusCarina spiral arm is probed in the borderline of the third and fourth quadrants at a distance from the Galactic centre of d 1 ∼ 6.4 kpc adopting R ⊙ = 7.2 kpc, or d 2 ∼ 7.2 kpc for R ⊙ = 8.0 kpc. Most ECs in our sample are located in the Perseus arm that is traced in the second and third quadrants and appear to be at Galactocentric distances in the range d 1 = 9 − 10.5 kpc or d 2 = 9.8 − 11.3 kpc. Dolidze 25, Bochum 2, and Camargo 445 are located in the Outer arm that extends along the second and third Galactic quadrants with a distance from the Galactic centre in the range of d 1 = 12.5 − 14.5 kpc or d 2 = 13.5 − 15.5 kpc. We find further evidence that in the Galaxy ECs are predominantly located within the thin disc and along spiral arms. They are excellent tools for tracing these Galactic features and therefore new searches for ECs can contribute to a better understanding of the Galactic structure. We also report an EC aggregate located in the Perseus arm.

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Section: Introductionmentioning

confidence: 99%

Tracing the Galactic spiral structure with embedded clusters

Camargo

Bonatto

Bica

2015

Monthly Notices of the Royal Astronomical Society

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“…Multiple spiral patterns Lépine et al (2011a) have argued that the corrotation radius of the spiral arms is located at solar radius, i.e. at R = 8.4 kpc; however based on the orbits of the Hyades and coma Berenices moving groups, Quillen & Minchev (2005) concluded that the 4:1 inner Lindblad resonance of the spiral arms is located at the solar position, placing the corrotation resonance at around 12 kpc.…”

Section: Spiral Arm Parametersmentioning

confidence: 99%

Radial migration of the Sun in the Milky Way: a statistical study

Martínez-Barbosa

Brown

Zwart

2014

Monthly Notices of the Royal Astronomical Society

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The determination of the birth radius of the Sun is important to understand the evolution and consequent disruption of the Sun's birth cluster in the Galaxy. Motivated by this fact, we study the motion of the Sun in the Milky Way during the last 4.6 Gyr in order to find its birth radius. We carried out orbit integrations backward in time using an analytical model of the Galaxy which includes the contribution of spiral arms and a central bar. We took into account the uncertainty in the parameters of the Milky Way potential as well as the uncertainty in the present day position and velocity of the Sun. We find that in general the Sun has not migrated from its birth place to its current position in the Galaxy (R ). However, significant radial migration of the Sun is possible when: 1) The 2 : 1 Outer Lindblad resonance of the bar is separated from the corrotation resonance of spiral arms by a distance ∼ 1 kpc. 2) When these two resonances are at the same Galactocentric position and further than the solar radius. In both cases the migration of the Sun is from outer regions of the Galactic disk to R , placing the Sun's birth radius at around 11 kpc. We find that in general it is unlikely that the Sun has migrated significantly from the inner regions of the Galactic disk to R .

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“…Du et al (2011) and Han et al (2011) observed H110α and H 2 CO 4.8 GHz lines simultaneously toward more than 200 candidates of UCHII regions with the Urumqi 25 m telescope, and obtained kinematic distances for about 20 HII regions. Lépine et al (2011) solved the kinematic distance ambiguity problem for more than 800 CS (2−1) emission sources , which are associated with the confident candidates of UCHII regions (Wood & Churchwell 1989). By analyzing the HI absorption data toward a sample of compact HII regions identified from the Red MSX Source Survey (Hoare et al 2005), Urquhart et al (2012) solved the kinematic distance ambiguity for about 105 HII regions.…”

Section: Hii Regionsmentioning

confidence: 99%

“…Some newly discovered HII regions or GMCs even as far as ∼20 kpc from the Sun Dame & Thaddeus 2011) provide important data to reveal the spiral structure in the outer Galaxy. The kinematic distance ambiguity for many HII regions, GMCs, and 6.7 GHz methanol masers has been solved (e.g., Roman-Duval et Lépine et al 2011;Anderson et al 2012;Urquhart et al 2012;Jones & Dickey 2012), which enables us to estimate their kinematic distances. In addition, the more reliable trigonometric or photometric distances of a number of HII regions or masers have been measured (e.g., Rygl et al 2010;Sato et al 2010a; Moisés et al 2011;Xu et al 2011Xu et al , 2013Russeil et al 2012;Zhang et al 2014;Foster & Brunt 2014).…”

Section: Introductionmentioning

confidence: 99%

The observed spiral structure of the Milky Way

Hou

Han

2014

A&A

237

233

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Context. The spiral structure of the Milky Way is not yet well determined. The keys to understanding this structure are to increase the number of reliable spiral tracers and to determine their distances as accurately as possible. HII regions, giant molecular clouds (GMCs), and 6.7 GHz methanol masers are closely related to high mass star formation, and hence they are excellent spiral tracers. The distances for many of them have been determined in the literature with trigonometric, photometric, and/or kinematic methods. Aims. We update the catalogs of Galactic HII regions, GMCs, and 6.7 GHz methanol masers, and then outline the spiral structure of the Milky Way. Methods. We collected data for more than 2500 known HII regions, 1300 GMCs, and 900 6.7 GHz methanol masers. If the photometric or trigonometric distance was not yet available, we determined the kinematic distance using a Galaxy rotation curve with the current IAU standard, R 0 = 8.5 kpc and Θ 0 = 220 km s −1 , and the most recent updated values of R 0 = 8.3 kpc and Θ 0 = 239 km s −1 , after velocities of tracers are modified with the adopted solar motions. With the weight factors based on the excitation parameters of HII regions or the masses of GMCs, we get the distributions of these spiral tracers.Results. The distribution of tracers shows at least four segments of arms in the first Galactic quadrant, and three segments in the fourth quadrant. The Perseus Arm and the Local Arm are also delineated by many bright HII regions. The arm segments traced by massive star forming regions and GMCs are able to match the HI arms in the outer Galaxy. We found that the models of three-arm and four-arm logarithmic spirals are able to connect most spiral tracers. A model of polynomial-logarithmic spirals is also proposed, which not only delineates the tracer distribution, but also matches the observed tangential directions.

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The spiral structure of the Galaxy revealed by CS sources and evidence for the 4:1 resonance

Cited by 40 publications

References 57 publications

Tracing the Galactic spiral structure with embedded clusters

Tracing the Galactic spiral structure with embedded clusters

Radial migration of the Sun in the Milky Way: a statistical study

The observed spiral structure of the Milky Way

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