The inner core of a BOK globule

Jones, T. J.; Hyland, A. R.; Bailey, J. D.

doi:10.1086/162247

Cited by 32 publications

(59 citation statements)

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“…These studies have shown that the relation between the extinction and polarization of the background star is far from unique and depends on the environment of the cloud. Thus although quite large values of polarization could be associated with large extinction (Hodapp 1987;Zaritsky et al 1987;Jones 1989), the polarization efficiency appears to be low for dark clouds (Jones et al 1984;Klebe & Jones 1990). It was also found that the polarization did not increase linearly with extinction (Jones 1989;Jarrett et al 1994).…”

Section: Introductionmentioning

confidence: 90%

Imaging polarimetry of some selected dark clouds

Sen

Gupta²,

Ramaprakash³

et al. 2000

Astron. Astrophys. Suppl. Ser.

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Abstract.A set of eight Bok Globules CB3, CB25, CB39, CB52, CB54, CB58, CB62 and CB246 were observed polarimetrically in white light, using our Imaging Polarimeter (IMPOL), from the 1.2 m IR telescope at Mount Abu, India. The observations were carried out on different nights during the period December 1997 and April 1998. The CCD images obtained from the instrument (IMPOL) were analyzed, to produce polarization map of the Bok Globules. The stars in the field, which are mostly background to the cloud show typically 2% of linear polarization. Clouds which are less dynamic (having 12 CO line widths ∆V < 2.5 km s −1 ), in general show slightly better alignment of polarization vectors with the projected direction of galactic plane. On the other hand the more dynamic group of clouds, has the polarization vectors more scattered and poorly aligned with the projected direction of the galactic plane. However one of the clouds observed CB58 does not follow this trend very well.

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Section: Introductionmentioning

confidence: 90%

Imaging polarimetry of some selected dark clouds

Sen

Gupta²,

Ramaprakash³

et al. 2000

Astron. Astrophys. Suppl. Ser.

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“…Based on the results from the CF analyses from optical (Andersson & Potter 2005) and NIR data (Jones et al 1984;Lada et al 2004; our Section 3.2), the results presented here thus seem to indicate that both the sight lines probed fall in the "diffuse" part of the super bubble, including the one toward PSR J1210−6550. This then suggests that the edge of the magnetized Coalsack cloud is quite sharp and located close to the lowest CO contour-at least in the direction of the magnetic field.…”

Section: Discussionmentioning

confidence: 52%

“…As discussed in the introduction, Lada et al (2004) used nearinfrared polarimetry (NIR) from Jones et al (1984) and their own deep 18 CO observations of Tapia's Globule 2 to estimate the magnetic field strength in this dark core. We here discuss this result in light of a reanalysis of the polarization data.…”

Section: The Magnetic Field In Tapia's Globulementioning

confidence: 99%

“…"Immediately apparent in Figure 4 is a definite change in polarization angle between the northern block (block E [...] Figure 6 shows the distribution of polarization angles from Jones et al (1984) where we have color coded the data from "block D" in blue (dark gray) and those from blocks E and F in yellow (light gray). The change in the average value of the polarization angles between the areas is clearly seen.…”

Section: The Magnetic Field In Tapia's Globulementioning

confidence: 99%

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On the Magnetic Field Through the Upper Centaurus-Lupus Super Bubble in the Vicinity of the Southern Coalsack

Andersson

2011

ApJ

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The Southern Coalsack is located in the interior of the Upper Centaurus-Lupus (UCL) super bubble and shows many traits that point to a much more energetic environment than might be expected from a dark, starless molecular cloud. A hot, X-ray emitting envelope surrounds the cloud, it has a very strong internal magnetic field, and its darkest core seems to be on astronomical timescales "just about" to start forming stars. In order to probe the magnetic environment of the cloud and to compare with the optical/near-infrared polarimetry-based field estimates for the cloud, we have acquired Faraday rotation measurements toward the pulsar PSR J1210−6550, probing the magnetic field in the vicinity of the cloud, and a comparison target, PSR J1435−5954, at a similar line-of-sight distance but several degrees from the cloud. Both lines of sight hence primarily probe the UCL super bubble. The earlier estimates of the magnetic field inside the Coalsack, using the Chandrasekhar-Fermi method on optical and near-infrared polarimetry, yield B ⊥ = 64-93 μG. However, even though PSR J1210−6550 is located only ∼30 arcmin from the (CO) edge of the cloud, the measured field strength is only B = −1.1 ± 0.2 μG. While thus yielding a very high field contrast to the cloud we argue that this might be understood as due to the effects on the cloud by the super bubble.

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“…Since the 1960s, unsuccessful searches have been conducted for H ii regions (Hidajat 1962;Gómez & Mendoza v 1976;Le Coarer et al 1992), flare, T Tauri, and OB stars (Weaver 1973;Muzzio & Orsatti 1977;Westerlund & Garnier 1989;Corradi & Franco 1995). Similarly, IR searches for young stellar objects (YSOs) have been in vain (Westerlund 1961;Jones et al 1980Jones et al , 1984Smyth & Sim 1980), and no IRAS sources seem to be associated with the denser globules (Nyman et al 1989;Kato et al 1999). In contrast, other nearby cloud complexes such as the Auriga, Chamaeleon, Lupus, Ophiucus, and Taurus molecular clouds (e.g., Ungerechts & Thaddeus 1987;Wilking et al 1989;Kenyon & Hartmann 1995) contain numerous YSOs.…”

Section: Introductionmentioning

confidence: 99%

Prestellar Cores in the Coalsack

Saul

Cunningham

Rathborne

et al. 2011

ApJ

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We present high spectral resolution millimeter mapped observations of seven prestellar cores in the Coalsack, including imaging in five optically thin molecular species of the kinematic structure of two of the densest cores, C2 and C4. Various collapse-critical indices are calculated; critical masses needed for collapse are consistently greater than those observed, the latter ranging from 0.4 to 2.4 M . The molecular emission in several of the cores shows line profiles with infall characteristics as well as elongated areas of increased line widths and reversals of center velocity gradients, implying that accretion disks may be forming.

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The inner core of a BOK globule

Cited by 32 publications

References 0 publications

Imaging polarimetry of some selected dark clouds

Imaging polarimetry of some selected dark clouds

On the Magnetic Field Through the Upper Centaurus-Lupus Super Bubble in the Vicinity of the Southern Coalsack

Prestellar Cores in the Coalsack

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