Magnetic field geometry of the large globule CB 34

Das, Ananta Kumar; Das, Himadri Sekhar; Medhi, Biman J.; Wolf, S.

doi:10.1007/s10509-016-2966-y

Cited by 6 publications

(31 citation statements)

References 54 publications

(89 reference statements)

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“…However, the correlation between these three parameters is still under debate. Certain studies have revealed a very good alignment between magnetic field orientation and outflow direction (Cohen et al 1984;Vrba et al 1986;Jones and Amini 2003;Wolf et al 2003;Hull et al 2013;Bertrang et al 2014;Soam et al 2015;Das et al 2016), whereas misalignment between the same has also been reported in several studies (e.g., Wolf et al 2003;Ménard and Duchéne 2004;Targon et al 2011;Krumholz et al 2013;Soam et al 2015). Based on MHD simulations, Matsumoto and Tomisaka (2004) and Matsumoto et al (2006) found that the alignment between the magnetic field direction and outflow direction depends on the strength of the magnetic field, i.e., stronger the magnetic field, better the alignment.…”

Section: Relative Orientation Between Various Quantities Of the Cloudmentioning

confidence: 78%

“…But Chapman et al (2013) reported a positive correlation between mean magnetic field direction and pseudodisk symmetry axis (minor axis) from the analysis of the 350µm polarization data for the seven cores. Das et al (2016) studied the correlation of mean magnetic field with the minor axis and outflow direction for a large globule CB34.…”

Section: Relative Orientation Between Various Quantities Of the Cloudmentioning

confidence: 99%

“…Polarimetric observation of these clouds at optical wavelength can give the information about the magnetic field orientation in the low-density edge region of clouds. However, the polarimetric observations in IR and sub-millimeter wavelength can range the magnetic field orientation in high density central region of clouds (Kane et al 1995;Alves et al 2008;Ward-Thompson et al 2009;Franco et al 2010 ;Paul et al 2012;Chakraborty et al 2014;Bertrang et al 2014;Chakraborty & Das 2016;Das et al 2016;Soam et al 2016 etc. ).…”

Section: Introductionmentioning

confidence: 99%

“…The study of magnetic field is important as it plays a major role in the evolution of dark clouds and may control the fragmentation of clouds to form stars (Mestel and Spitzer 1956;Nakano and Nakamura 1978;Mouschovias & Morton 1991;Li & Nakamura 2004). Previously our group performed the polarimetric study of two Bok Globules CB 34 (Das et al 2016) and CB 130 (Chakraborty and Das 2016) which enriched the knowledge about the magnetic field geometry of two globules. Das et al (2016) studied magnetic field regions near two submm cores C 1 and C 2 , and estimated the magnetic field strength of two cores.…”

Section: Introductionmentioning

confidence: 99%

“…Previously our group performed the polarimetric study of two Bok Globules CB 34 (Das et al 2016) and CB 130 (Chakraborty and Das 2016) which enriched the knowledge about the magnetic field geometry of two globules. Das et al (2016) studied magnetic field regions near two submm cores C 1 and C 2 , and estimated the magnetic field strength of two cores. They also reported a correlation between the mean magnetic field, the minor axis and outflow direction for both the cores of the cloud.…”

Section: Introductionmentioning

confidence: 99%

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Bok globule CB 17: polarization, extinction and distance

Choudhury

Barman

Das

et al. 2019

Monthly Notices of the Royal Astronomical Society

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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.

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Section: Relative Orientation Between Various Quantities Of the Cloudmentioning

confidence: 78%

Section: Relative Orientation Between Various Quantities Of the Cloudmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Bok globule CB 17: polarization, extinction and distance

Choudhury

Barman

Das

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Magnetic fields in Bok globules: multi-wavelength polarimetry as tracer across large spatial scales

Jorquera

Bertrang

2018

A&A

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Context. The role of magnetic fields in the process of star formation is a matter of continuous debate. Clear observational proof of the general influence of magnetic fields on the early phase of cloud collapse is still pending. First results on Bok globules with simple structures indicate dominant magnetic fields across large spatial scales (Bertrang et al. 2014). Aims. The aim of this study is to test the magnetic field influence across Bok globules with more complex density structures. Methods. We apply near-infrared polarimetry to trace the magnetic field structure on scales of 10 4 −10 5 au (∼ 0.05−0.5pc) in selected Bok globules. The combination of these measurements with archival data in the optical and sub-mm wavelength range allows us to characterize the magnetic field on scales of 10 3 − 10 6 au (∼ 0.005 − 5pc). Results. We present polarimetric data in the near-infrared wavelength range for the three Bok globules CB34, CB56, and [OMK2002]18, combined with archival polarimetric data in the optical wavelength range for CB34 and CB56, and in the submillimeter wavelength range for CB34 and [OMK2002]18. We find a strong polarization signal (P ≥ 2%) in the near-infrared for all three globules. For CB34, we detect a connection between the structure on scales of 10 4 − 10 5 au (∼ 0.05 − 0.5pc) to 10 5 − 10 6 au (∼ 0.5 − 5pc). For CB56, we trace aligned polarization segments in both the near-infrared and optical data, suggesting a connection of the magnetic field structure across the whole globule. In the case of [OMK2002]18, we find ordered polarization structures on scales of 10 4 − 10 5 au (∼ 0.05 − 0.5pc). Conclusions. We find strongly aligned polarization segments on large scales which indicate dominant magnetic fields across Bok globules with complex density structures. To reconcile our findings in globules, the lowest mass clouds known, and the results on intermediate (e.g., Taurus) and more massive (e.g., Orion) clouds, we postulate a mass dependent role of magnetic fields, whereby magnetic fields appear to be dominant on low and high mass but rather sub-dominant on intermediate mass clouds.

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The Relative Orientation between Local Magnetic Field and Galactic Plane in Low Latitude Dark Clouds

Choudhury¹,

Das²,

Medhi³

et al. 2022

Res. Astron. Astrophys.

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In this work, we study the magnetic field morphology of selected star-forming clouds spread over the galactic latitude ($b$) range, $-10^\circ$ to $10^\circ$. The polarimetric observation of clouds CB24, CB27 and CB188 are conducted to study the magnetic field geometry of those clouds using the 104-cm Sampurnanand Telescope (ST) located at ARIES, Manora Peak, Nainital, India. These observations are combined with those of 14 further low latitude clouds available in the literature. Most of these clouds are located within a distance range 140 to 500 pc except for CB3 ($\sim$2500 pc), CB34 ($\sim$1500 pc), CB39 ($\sim$1500 pc) and CB60 ($\sim$1500 pc). Analyzing the polarimetric data of 17 clouds, we find that the alignment between the envelope magnetic field ($\theta_{B}^{env}$) and Galactic plane ($\theta_{GP}$) of the low-latitude clouds varies with their galactic longitudes ($l$). We observe a strong correlation between the longitude (\textit{l}) and the offset ($\theta_{off}=|\theta_B^{env}-\theta_{GP}|$) which shows that $\theta_{B}^{env}$ is parallel to the Galactic plane (GP) when the clouds are situated in the region, $115^\circ<l<250^\circ$. However, $\theta_{B}^{env}$ has its own local deflection irrespective of the orientation of $\theta_{GP}$ when the clouds are at $l<100^\circ$ and $l>250^\circ$. To check the consistency of our results, the stellar polarization data available at Heiles (2000) catalogue are overlaid on DSS image of the clouds having mean polarization vector of field stars. The results are almost consistent with the Heiles data and a systematic discussion is presented in the paper. The effect of turbulence of the cloud is also studied which may play an important role in causing the misalignment phenomenon observed between $\theta_{B}^{env}$ and $\theta_{GP}$. We have used \textit{Herschel}\footnote{Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.} \textit{SPIRE} 500 $\mu m$ and \textit{SCUBA} 850 $\mu m$ dust continuum emission maps in our work to understand the density structure of the clouds.

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Magnetic field geometry of the large globule CB 34

Cited by 6 publications

References 54 publications

Bok globule CB 17: polarization, extinction and distance

Bok globule CB 17: polarization, extinction and distance

Magnetic fields in Bok globules: multi-wavelength polarimetry as tracer across large spatial scales

The Relative Orientation between Local Magnetic Field and Galactic Plane in Low Latitude Dark Clouds

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