A Sino-German $\mathsf{\lambda}$6 cm polarization survey of the Galactic plane

Sun, Xiaohui; Han, J. L.; Reich, W.; Reich, P.; Shi, Wu; Wielebinski, R.; Fürst, E.

doi:10.1051/0004-6361:20066001

Cited by 93 publications

(146 citation statements)

References 56 publications

Supporting

Mentioning

139

Contrasting

Order By: Relevance

“…The actual distance from γ Cas to IC 63 is d⋆ = d ⋆,sky / cos(58 • ) = 2.45pc. In addition, both the position angles of the optical polarization in the nebula and synchrotron measurements in the area encompassing IC 63 (Sun et al 2007) show a projected magnetic field closely parallel to the Galactic plane. While direct determinations of the three dimensional structure of the magnetic field in the region are not available, we can estimate the over-all field orientation by assuming that it follows the spiral arms.…”

Section: Physical Model Of Ic 63 and Model Set Upmentioning

confidence: 93%

Modelling grain alignment by radiative torques and hydrogen formation torques in reflection nebula

Hoang

Lazarían

Andersson

2015

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Reflection nebulae-dense cores-illuminated by surrounding stars offer a unique opportunity to directly test our quantitative model of grain alignment based on radiative torques (RATs) and to explore new effects arising from additional torques. In this paper, we first perform detailed modeling of grain alignment by RATs for the IC 63 reflection nebula illuminated both by a nearby γ Cas star and the diffuse interstellar radiation field. We calculate linear polarization p λ of background stars by radiatively aligned grains and explore the variation of fractional polarization (p λ /A V ) with visual extinction A V across the cloud. Our results show that the variation of p V /A V versus A V from the dayside of IC 63 to its center can be represented by a power-law (p V /A V ∝ A η V ) with different slopes depending on A V . We find a shallow slope η ∼ −0.1 for A V < 3 and a very steep slope η ∼ −2 for A V > 4. We then consider the effects of additional torques due to H 2 formation and model grain alignment by joint action of RATs and H 2 torques. We find that p V /A V tends to increase with an increasing magnitude of H 2 torques. In particular, the theoretical predictions obtained for p V /A V and peak wavelength λ max in this case show an improved agreement with the observational data. Our results reinforce the predictive power of the RAT alignment mechanism in a broad range of environmental conditions and show the effect of pinwheel torques in environments with efficient H 2 formation. Physical parameters involved in H 2 formation may be constrained using detailed modeling of grain alignment combined with observational data. In addition, we discuss implications of our modeling for interpreting latest observational data by Planck and other ground-based instruments.

show abstract

Section: Physical Model Of Ic 63 and Model Set Upmentioning

confidence: 93%

Modelling grain alignment by radiative torques and hydrogen formation torques in reflection nebula

Hoang

Lazarían

Andersson

2015

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…Stokes parameters I, U, and Q were stored simultaneously for each map. The system set-up and the data reduction were described in detail by Sun et al (2006Sun et al ( , 2007 and Gao et al (2010).…”

Section: The λ6 CM Survey and The Large Snrsmentioning

confidence: 99%

“…Instrumental effects in Stokes U and Q maps were corrected for the leakage of total intensity I into the polarization channels as described by Sun et al (2007).…”

Section: The λ6 CM Survey and The Large Snrsmentioning

confidence: 99%

A Sino-Germanλ6 cm polarization survey of the Galactic plane

Gao

Han

Reich

et al. 2011

A&A

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…There are also some individual discoveries, although not many. The SinoGerman λ6 cm polarization survey of the Galactic plane 1 (Sun et al 2007(Sun et al , 2011a; Gao et al 2010;Xiao et al 2011) conducted by the Urumqi 25-m radio telescope provides a good hunting ground for discovering new Galactic SNRs. Gao et al (2011) identified two new faint SNRs G25.1−2.3 and G178.2−4.2.…”

Section: Introductionmentioning

confidence: 99%

Discovery of a new supernova remnant G150.3+4.5

Gao

Han

2014

A&A

Self Cite

View full text Add to dashboard Cite

Context. Large-scale radio continuum surveys have good potential for discovering new Galactic supernova remnants (SNRs). Surveys of the Galactic plane are often limited in the Galactic latitude of |b| ∼ 5 • . SNRs at high latitudes, such as the Cygnus Loop or CTA 1, cannot be detected by surveys in such limited latitudes. Aims. Using the available Urumqi λ6 cm Galactic plane survey data, together with the maps from the extended ongoing λ6 cm medium latitude survey, we wish to discover new SNRs in a large sky area. Methods. We searched for shell-like structures and calculated radio spectra using the Urumqi λ6 cm, Effelsberg λ11 cm, and λ21 cm survey data. Radio polarized emission and evidence in other wavelengths are examined for the characteristics of SNRs. Results. We discover an enclosed oval-shaped object G150.3+4.5 in the λ6 cm survey map. It is about 2.• 5 wide and 3 • high. Parts of the shell structures can be identified well in the λ11 cm, λ21 cm, and λ73.5 cm observations. The Effelsberg λ21 cm total intensity image resembles most of the structures of G150.3+4.5 seen at λ6 cm, but the loop is not closed in the northwest. High resolution images at λ21 cm and λ73.5 cm from the Canadian Galactic Plane Survey confirm the extended emission from the eastern and western shells of G150.3+4.5. We calculated the radio continuum spectral indices of the eastern and western shells, which are β ∼ −2.4 and β ∼ −2.7 between λ6 cm and λ21 cm, respectively. The shell-like structures and their non-thermal nature strongly suggest that G150.3+4.5 is a shell-type SNR. For other objects in the field of view, G151.4+3.0 and G151.2+2.6, we confirm that the shell-like structure G151.4+3.0 very likely has a SNR origin, while the circular-shaped G151.2+2.6 is an H ii region with a flat radio spectrum associated with optical filamentary structure, Hα, and infrared emission.

show abstract

A Sino-German $\mathsf{\lambda}$6 cm polarization survey of the Galactic plane

Cited by 93 publications

References 56 publications

Modelling grain alignment by radiative torques and hydrogen formation torques in reflection nebula

Modelling grain alignment by radiative torques and hydrogen formation torques in reflection nebula

A Sino-Germanλ6 cm polarization survey of the Galactic plane

Discovery of a new supernova remnant G150.3+4.5

Contact Info

Product

Resources

About