Probing the magnetic fields in L1415 and L1389

Soam, Archana; Lee, Chang Won; Maheswar, G.; Kim, Gwanjeong; Neha, S.; Kim, Mi-Ryang

doi:10.1093/mnras/stw2454

Cited by 11 publications

(17 citation statements)

References 81 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…We have presented the polarization values and the position angle of polarization of these 19 field stars of CB17 along with their right ascensions and declinations in The mean value of polarization of these 19 stars is found to be < p > = 3.52% with a standard deviation of σ p = 0.89% and the mean value of position angle is < θ >= 136 • with a standard deviation σ θ = 2.84 • . The results obtained by Soam et al (2016) for 120 field stars (mainly in northern region of CB17) were < p >= (3.3 ± 0.9)% and < θ >= (137 ± 6) • .…”

Section: Optical Polarizationmentioning

confidence: 91%

“…A cometary-shaped morphology of the cloud has been observed in Herschel-SPIRE (Spectral and Photometric Imaging Receiver;Griffin et al 2010) images of CB17 at 500 µm (Launhardt et al 2013). Optical polarimetric observations of CB17 were also conducted by Soam et al (2016) to understand the envelope magnetic field. This globule was extensively studied by other investigators which enriched the knowledge about this globule (Kane & Clemens 1997;Benson et al 1998;Pavlyuchenkov et al 2006;Chen et al 2012;Schmalzl et al 2014 etc.).…”

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Bok globule CB 17: polarization, extinction and distance

Choudhury

Barman

Das

et al. 2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

In this paper, the results obtained from the polarimetric study of a Bok globule CB17 in both optical and sub-millimeter wavelength are presented. The optical polarimetric observations in R-band (λ = 630 nm, ∆λ = 120 nm) were conducted from 1.04-meter Sampurnanand Telescope, ARIES, Nainital, India on 9th March 2016, while, the sub-mm polarimetric data are taken from the SCUPOL data archive which has been reanalyzed. The contours of Herschel ¶ SPIRE 500µm dust continuum emissions of CB17 (typically a cometary-shaped globule) are overlaid on the DSS image of CB17 along with polarization vectors (optical and submm). The magnetic field strength at the core of the globule is estimated to be 99µG. Using the Near-Infrared photometric technique and Gaia data, the distance to CB17 is found to be 253 ± 43 parsec. A correlation between the various quantities of the globule is also studied. It is observed that the magnetic field in the cloud core as revealed by polarization measurements at the sub-millimeter dust emission is found to be almost aligned along the minor axis of the globule which fits the magnetically regulated star formation model. The misalignment between core-scale magnetic field direction and molecular outflow direction is also found.

show abstract

Section: Optical Polarizationmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 98%

Bok globule CB 17: polarization, extinction and distance

Choudhury

Barman

Das

et al. 2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…To obtain the intrinsic polarization from the cloud dust only, we subtracted the polarization values of the foreground stars (shown in Table 4) from our measured values towards the clouds. For this purpose we followed the procedure with detailed discussion given in our previous papers (Soam et al, 2013(Soam et al, , 2017a. We have overlaid the vectors with corrected polarization angles towards IC1396A, BRC 38, BRC 37 and BRC 39 in Fig.…”

Section: Subtraction Of Foreground Polarization Componentmentioning

confidence: 99%

“…The dispersion in θ is then corrected by the uncertainty in θ using the steps given in Lai et al (2001) and Franco et al (2010). In this procedure, the dispersion is corrected in quadrature by the polarization angle using ∆θ = (σ std 2 − σ θ 2 ) 1/2 , where the mean error σ θ was calculated from σ θ = Σσ θi /N, here σ θi is the estimated uncertainty and σ std is the standard deviation in position angle (for details see Soam et al (2017a)). We adopted the CO(J=1-0) line FWHM from our ongoing molecular line survey of BRCs using Taeduk Radio Astronomical Observatory (TRAO; Soam et al in prep.).…”

Section: Magnetic Field Strengthmentioning

confidence: 99%

Magnetic fields in multiple bright-rimmed clouds in different directions of H ii region IC 1396

Soam

Maheswar

Lee

et al. 2018

Monthly Notices of the Royal Astronomical Society

Self Cite

View full text Add to dashboard Cite

Bright-rimmed clouds form on the edges of H II regions affected by the high energy radiation from a central ionizing source. The UV radiation from the ionizing source results in compression and ionization causing either cloud disruption or further star formation. In this work, we present R−band polarization measurements towards four bright-rimmed clouds, IC1396A, BRC 37, BRC 38, and BRC 39, located in the different directions of the H II region, Sh2-131, in order to map magnetic fields (B-fields) in the plane of the sky. These BRCs are illuminated by the O star HD 206267 and present a range of projected on sky geometries. This provides an opportunity to understand the magnetized evolution of BRCs. The B-field geometries of the clouds deduced from the polarization data, after correction for foreground ISM contamination, are seen to be connected to the ambient B-fields on the large scale. They seem to play an important role in shaping the cloud IC1396A and BRC 37. BRCs 38 and 39 show a broader and snubber head morphology possibly due to the B-fields being aligned with incoming radiation as explained in the simulations. A good general agreement is noted on comparing our observational results with the simulations supporting the importance of B-fields in BRC evolution. This work is the first step towards systematic mapping the B-fields morphology in multiple BRCs in an expanding H II region, extending the work presented by Soam et al. (2017b).

show abstract

“…These fragments may continue to amass material through gravitational inflow resulting in a flow pattern parallel to the filament axis (e.g., Balsara et al 2001;Banerjee et al 2006). Correlated magnetic fields on scales of 1-10 pc have been observed in interstellar clouds (e.g., Vrba et al 1976;Heyer et al 1987;McCutcheon et al 1986;Goodman et al 1992;Pereyra & Magalhães 2004;Chapman et al 2011;Soam et al 2015Soam et al , 2017Wang et al 2017;Clemens et al 2018). The magnetic fields may play an important role in regulating these flows.…”

Section: Introductionmentioning

confidence: 99%

Distance, magnetic field and kinematics of a filamentary cloud LDN 1157

Sharma,

Maheswar,

Soam

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

Context. LDN 1157 is one of the several clouds situated in the cloud complex, LDN 1147/1158. The cloud presents a coma-shaped morphology with a well-collimated bipolar outflow emanating from a Class 0 protostar, LDN 1157-mm, residing deep inside the cloud. Aims. The main goals of this work are (a) to map the inter-cloud magnetic field (ICMF) geometry of the region surrounding LDN 1157 to investigate its relationship with the cloud morphology, with the outflow direction and with the core magnetic field (CMF) geometry inferred from the mm-and sub-mm polarization results from the literature, and (b) to investigate the kinematic structure of the cloud. Methods. We carried out optical (R-band) polarization observations of the stars projected on the cloud to map the parsec-scale magnetic field geometry and made spectroscopic observations of the entire cloud in 12 CO, C 18 O and N 2 H + (J=1-0) lines to investigate its kinematic structure. Results. We obtained a distance of 340±3 pc to the LDN 1147/1158, complex based on the Gaia DR2 parallaxes and proper motion values of the three young stellar objects (YSOs) associated with the complex. A single filament of ∼ 1.2 pc in length (traced by the Filfinder algorithm) and ∼ 0.09 pc in width (estimated using the Radfil algorithm) is found to run all along the coma-shaped cloud. Based on the relationships between the ICMF, CMF, filament orientations, outflow direction, and the presence of an hour-glass morphology of the magnetic field, it is likely that the magnetic field had played an important role in the star formation process in LDN 1157. LDN 1157-mm is embedded in one of the two high density peaks detected using the Clumpfind algorithm. Both the detected clumps are lying on the filament and show a blue-red asymmetry in the 12 CO line. The C 18 O emission is well correlated with the filament and presents a coherent structure in velocity space. Combining the proper motions of the YSOs and the radial velocity of LDN 1147/1158 and an another complex LDN 1172/1174 which is situated ∼ 2 • east of it, we found that both the complexes are moving collectively toward the Galactic plane. The filamentary morphology of the east-west segment of LDN 1157 may have formed as a result of mass lost by ablation due to the interaction of the moving cloud with the ambient interstellar medium.

show abstract

Probing the magnetic fields in L1415 and L1389

Cited by 11 publications

References 81 publications

Bok globule CB 17: polarization, extinction and distance

Bok globule CB 17: polarization, extinction and distance

Magnetic fields in multiple bright-rimmed clouds in different directions of H ii region IC 1396

Distance, magnetic field and kinematics of a filamentary cloud LDN 1157

Contact Info

Product

Resources

About