The spiral structure of our Milky Way Galaxy

Hou, Ligang; Han, J. L.; Shi, Wu

doi:10.1051/0004-6361/200809692

Cited by 163 publications

(240 citation statements)

References 60 publications

Supporting

Mentioning

223

Contrasting

Unclassified

Order By: Relevance

“…Up to now the spiral arm models are obtained by fitting the spiral arm tracer with weighting factors based on the excitation parameter of H ii regions (e.g. Russeil 2003) or the mass of GMCs (Hou et al 2009) or by finding the tangential direction to the arms from CO or near-infrared longitude profiles (e.g. Benjamin 2008;Drimmel 1986).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Giving physical significance to the Hi-GAL data: determining the distance of cold dusty cores in the Milky Way

Russeil

Pestalozzi

Mottram

et al. 2011

A&A

View full text Add to dashboard Cite

Context. Hi-GAL, an open time key-project of the Herschel satellite, was awarded 343 hours observing time to carry out a 5-band photometric imaging survey at 70, 160, 250, 350, and 500 μm of a |b| ≤ 1 • wide strip of the Milky Way Galactic plane in the longitude range −70 • ≤ l ≤ 70 • . Two 2 • × 2 • fields centred at l = 30 • and l = 59 • have been observed with the SPIRE and PACS photometric cameras in parallel mode during the Herschel science demonstration phase (SDP). From the images, compact sources are extracted for which the distance must be established in order to determine their physical properties. Aims. The aim of this paper is to present the distance determination strategy for the Hi-GAL compact sources. We illustrate this strategy for the two fields at l = 30 • and l = 59 • . Methods. The first step to determine the distance is to establish the LSR (local standard of rest) velocity of each compact source. The kinematic distance is then determined assuming a rotation curve for our Galaxy. To resolve the distance ambiguity for sources within the solar circle, we adopt a multiwavelength approach combining extinction maps, optical, and near infrared images, and velocity information from NH 3 , CO and HI data. When sources can be kinematically linked to optical H ii regions, the stellar distance of the exciting stars, when known, can be attributed to all linked sources. Results. In the two 2 • × 2 • SDP fields, 2678 compact sources have been identified and listed in the band-merged catalogue. About 93% of these sources have been assigned a radial velocity and distance. Conclusions. A multiwavelength approach is necessary to assign the correct velocity to sources (especially when CO spectra have a lot of features) and to determine the distance by solving the distance ambiguity. Also, several Hi-GAL sources seem to be in the interarm region. These sources have to be investigated with dedicated programme to be compared with sources located in the spiral arms.

show abstract

Section: Discussionmentioning

confidence: 99%

“…From Hou et al (2009) and Russeil et al (2007) the l = 59 • line of sight should pass close to the Sagittarius arm tangency and then cross the Perseus arm and the Cygnus arm (also called the external arm) at ∼9.2 and ∼12.9 kpc. Most Hi-GAL sources can be placed in the Sagittarius and Perseus spiral arms (Fig.…”

Section: The Galactic Contextmentioning

confidence: 99%

Giving physical significance to the Hi-GAL data: determining the distance of cold dusty cores in the Milky Way

Russeil

Pestalozzi

Mottram

et al. 2011

A&A

View full text Add to dashboard Cite

show abstract

“…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

View full text Add to dashboard Cite

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.

show abstract

“…The inner Galactic plane is particularly interesting, but requires high-frequency observations to overcome strong depolarization effects. Radio continuum emission originates predominantly in spiral arms, and there are several arms along the line-of-sight towards the inner Galaxy (Hou et al 2009). …”

Section: Introductionmentioning

confidence: 99%

A Sino-Germanλ6 cm polarization survey of the Galactic plane

Sun

Reich

Han

et al. 2011

A&A

Self Cite

View full text Add to dashboard Cite

Aims. We study polarized short-wavelength emission from the inner Galaxy, which is nearly invisible at long wavelengths because of depolarization. We attempt to obtain information on the diffuse continuum emission at short wavelengths to help us to separate Galactic thermal and non-thermal components. Methods. We conducted a total intensity and polarization survey of the Galactic plane at λ6 cm using the Urumqi 25 m telescope for the Galactic longitude range of 10 • ≤ l ≤ 60 • and the Galactic latitude range of |b| ≤ 5 • . Missing absolute zero levels of Stokes U and Q maps were restored by extrapolating the WMAP five-year K-band polarization data. For total intensities, we recovered missing large-scale components by referring to the Effelsberg λ11 cm survey. Results. Total intensity and polarization maps are presented with an angular resolution of 9. 5 and a sensitivity of 1 mK T B and 0.5 mK T B in total and polarized intensity, respectively. The λ6 cm polarized emission in the Galactic plane originates within about 4 kpc distance, which increases for polarized emission out of the plane. The polarization map shows "patches", "canals", and "voids" with no correspondence in total intensity. We attribute the patches to turbulent magnetic field cells. Canals are caused by abrupt variation in the polarization angles at the boundaries of patches rather than by foreground Faraday screens. The superimposition of foreground and Faraday screen rotated background emission almost cancels the polarized emission locally, such that polarization voids appear. By modelling the voids, we estimate the Faraday screen's regular magnetic field along the line-of-sight to be larger than about 8 μG. We separated thermal (free-free) and non-thermal (synchrotron) emission according to their different spectral indices. The spectral index for the synchrotron emission is based on WMAP polarization data. The fraction of thermal emission at λ6 cm is about 60% in the plane. Conclusions. The Sino-German λ6 cm polarization survey of the inner Galaxy provides new insights into the properties of the magnetized interstellar medium for this very complex Galactic region, which is Faraday thin up to about 4 kpc in the Galactic plane. Within this distance polarized patches are identified as intrinsic structures related to turbulent Galactic magnetic fields of spatial scales from 20(d/4 kpc) to 200(d/4 kpc) pc.

show abstract

The spiral structure of our Milky Way Galaxy

Cited by 163 publications

References 60 publications

Giving physical significance to the Hi-GAL data: determining the distance of cold dusty cores in the Milky Way

Giving physical significance to the Hi-GAL data: determining the distance of cold dusty cores in the Milky Way

Tracing the Galactic spiral structure with embedded clusters

A Sino-Germanλ6 cm polarization survey of the Galactic plane

Contact Info

Product

Resources

About