A radio catalog of Galactic HII regions for applications from decimeter to millimeter wavelengths

Paladini, R.; Burigana, C.; Davies, R. D.; Maino, D.; Bersanelli, M.; Cappellini, B.; Platania, P.; Smoot, George F.

doi:10.1051/0004-6361:20021466

Cited by 142 publications

(190 citation statements)

References 38 publications

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“…All of them except source A were believed to be parts of the SNR. The point-like source A was listed as an H ii region by Paladini et al (2003) according to Felli & Churchwell (1972). However, this source also named as 4C 16.15 clearly has a nonthermal spectrum (Vollmer et al 2005) and is therefore not an H ii region.…”

Section: Resultsmentioning

confidence: 99%

A Sino-Germanλ6 cm polarization survey of the Galactic plane

Gao

Han

Reich

et al. 2011

A&A

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Context.Observations of large supernova remnants (SNRs) at high frequencies are rare, but provide valuable information about their physical properties. Aims. The total intensity and polarization properties of 16 large SNRs in the Galactic plane are investigated based on observations of the Urumqi λ6 cm polarization survey of the Galactic plane with an angular resolution of 9. 5. Methods. We extracted total intensity and linear polarization maps of large SNRs from the Urumqi λ6 cm survey, obtained their integrated flux densities, and derived the radio spectra by using these flux densities together with previously published flux densities at various frequencies. In particular, Effelsberg λ11 cm and λ21 cm survey data were used to calculate integrated flux densities. The λ6 cm polarization data also delineate the magnetic field structures of the SNRs. Results. We present the first total intensity maps at λ6 cm for SNRs G106.3+2.7, G114.3+0.3, G116.5+1.1, G166.0+4.3 (VRO 42.05.01), G205.5+0.5 (Monoceros Nebula), and G206.9+2.3 (PKS 0646+06) and the first polarization measurements at λ6 cm for SNRs G82.2+5.3 (W63), G106.3+2.7, G114.3+0.3, G116.5+1.1, G166.0+4.3 (VRO 42.05.01), G205.5+0.5 (Monoceros Nebula), and G206.9+2.3 (PKS 0646+06). Most of the newly derived integrated radio spectra are consistent with previous results. The new flux densities obtained from the Urumqi λ6 cm, Effelsberg λ11 cm and λ21 cm surveys are crucial to determine the spectra of SNR G65.1+0.6, G69.0+2.7 (CTB 80), G93.7−0.2, and G114.3+0.3. We find that G192.8−1.1 (PKS 0607+17) consists of background sources, H ii regions, and extended diffuse emission of thermal nature, and conclude that G192.8−1.1 is not a SNR.

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Section: Resultsmentioning

confidence: 99%

A Sino-Germanλ6 cm polarization survey of the Galactic plane

Gao

Han

Reich

et al. 2011

A&A

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“…Columns 3-5 provide the values of C(Hβ) calculated from the stellar photometry, which are given by C(Hβ) = 1.5E(B − V), from the nebular Hγ/Hβ line ratio, and from the ratio of the radio continuum flux density to the Hβ flux, respectively. Columns 6-8 provide the values of N c obtained from the summed ionising photon rates of individual stars, from the observed Hβ line fluxes, and from the radio continuum flux densities at 2.7 GHz (Paladini et al 2003), respectively. We adopted the values of N c found by Schaerer & de Koter (1997) for stars of different spectral types.…”

Section: Resultsmentioning

confidence: 99%

Spectral classification and distance determination of stars in nine southern Galactic $\ion{H}{ii}$ regions

Pinheiro

Copetti

Oliveira

2010

A&A

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Aims. We attempt to identify the ionising stars and to determine the photometric distances of nine southern Galactic H ii regions.Methods. We carried out optical spectroscopy and UBV photometry of the stellar content of these objects. The distance of individual stars were obtained by spectroscopic parallax. To avoid using a fixed value for the total-to-selective extinction ratio R V , the reddening A V was determined directly by the colour-difference approach by comparing our V apparent magnitudes and the JHK magnitudes from the 2MASS survey with the intrinsic colour indices. Results. As types O or B, we classified 24 of the 31 stars for which optical spectra were obtained. In particular, we identified two new O stars, one in RCW 98 and the other in RCW 99. The values of reddening obtained correspond to a mean R V = 3.44, which is about 10% higher than the value found for field stars. For three of the H ii regions studied (Bran 186, NGC 2626, and RCW 32), the distance estimates (with errors from 25% to 50%) were based on the data obtained for only one star. For the other six objects (NGC 3503, NGC 6334, RCW 55, RCW 87, RCW 98, and RCW 99), we obtained more precise photometric distances (with a mean error of ≈18%) calculated to be the median of the parallax distances obtained for two to six different stars in each nebulae. The parallax distances of individual stars belonging to a given nebula were similar to each other, with internal errors smaller than 5%, as a consequence of the method used to derive the reddening correction A V . The distance of 1.23 ± 0.30 kpc obtained for RCW 87 disagrees with the value of 7.6 kpc previously found. Conclusions. The dispersion in individual distance estimates for stars in a given nebula can be significantly reduced by calculating the reddening A V from a comparison between the V and the 2MASS JHK magnitudes instead of using A V = R V E(B − V) with a fixed value for R V . Therefore, more precise distances can be calculated with our proposed method.

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“…Most of the known H ii regions were catalogued by Paladini et al (2003) and Hou et al (2009). They are visible in the I maps.…”

Section: H II Regionsmentioning

confidence: 99%

A Sino-Germanλ6 cm polarization survey of the Galactic plane

Sun

Reich

Han

et al. 2011

A&A

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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.

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A radio catalog of Galactic HII regions for applications from decimeter to millimeter wavelengths

Cited by 142 publications

References 38 publications

A Sino-Germanλ6 cm polarization survey of the Galactic plane

A Sino-Germanλ6 cm polarization survey of the Galactic plane

Spectral classification and distance determination of stars in nine southern Galactic $\ion{H}{ii}$ regions

A Sino-Germanλ6 cm polarization survey of the Galactic plane

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