An H I cloud in the Pleiades - A cloud-cluster collision?

Gordon, Kurtiss J.; Arny, Thomas T.

doi:10.1086/113565

Cited by 12 publications

(19 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Figure 23 we show the projection on the sky of the stars observed in the present study and in W01, toward the Pleiades cluster, and also the H i clouds and the H i hole detected by Gordon & Arny (1984). In the figure we observe that negative radial velocity components-cloud AG3-are observed mainly toward stars toward the H i hole; the only exceptions are stars 70 and 72, but their lines of sight fall close to the hole.…”

Section: No 2 2003mentioning

confidence: 51%

“…This motion away from Scorpio-Centaurus is shown by the most local interstellar gas in every direction from the Sun. Gordon & Arny (1984). Two-digit labels show stars observed in this work, identified as in Table 1, three-digit labels show stars observed by White at al.…”

Section: Kinematical Picture Of the Interstellar Gas In The Volume Obmentioning

confidence: 72%

“…The interaction of stars in the Pleiades cluster with the surrounding interstellar gas has been the focus of a series of papers in which optical and radio observations have been used to reveal a complex kinematical structure toward the cluster (Gordon & Arny 1984;White 1984aWhite , 1984bWhite , 1988 Bally & White 1986;White & Bally 1993;White et al 2001, hereafter W01). Those observations show a clear kinematical distinction between interstellar absorption lines observed in Na i and Ca ii and those observed in CH + and CO. White & Bally (1993) concluded that the Ca ii absorption occurs in mostly atomic gas, whose LSR velocity vector projects along the line of sight toward the cluster as $+7 km s À1 , and that the CH + absorption arises in mostly molecular gas, moving in the LSR with a velocity vector which projects along this line of sight as $+10 km s À1 .…”

Section: Clouds Ag3 Ag6 and The Pleiades Wakementioning

confidence: 99%

“…Similarly, '' shadowing '' experiments made with the EUVE satellite (Lieu et al 1993;Berghö fer et al 1998) have shown the presence of a similar cloud toward (l, bÞ ¼ ð165 , À35 ) whose near edge is within 40 pc from the Sun. Further from the Sun toward the second and third Galactic quadrants kinematical data have been published for individual lines of sight (Crawford, Lallement, & Welsh 1998;Dupin & Gry 1998a, 1998bGry & Dupin 1998), or for neighboring lines of sight toward the Pleiades cluster (Gordon & Arny 1984;White & Bally 1993) but the only large-scale analysis of the kinematics of the gas in this region is still the study of the kinematics of the local interstellar medium (LISM) made by Crutcher (1982) in which the gas was shown to be flowing in the LSR with velocity vector v C v C ; l C ; b C ð Þ¼ð 15:7 km s À1 , 166=3, +9=2). Although this velocity vector has been considered to be representative of the large-scale motion within the LISM, we now know that large differences can be found when the kinematics of the intervening gas are explored on smaller scales.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Kinematical Structure of the Local Interstellar Medium: The Galactic Anticenter Hemisphere

Genova

Beckman

2003

ASTROPHYS J SUPPL S

View full text Add to dashboard Cite

A survey of interstellar Na i D1 and D2 absorption features in the spectra of 104 early-type stars in the second and third Galactic quadrants reveals the large-scale kinematics of the interstellar gas within the Galactic anticenter hemisphere at distances from the Sun between $70 and $250 pc. Employing a technique that uses both the radial velocities and column densities of the Na i absorptions produced by the intervening gas we have identified the velocity vectors and determined the spatial distribution of eight interstellar clouds in the volume explored. The average internal H i + H 2 densities of the clouds range between 0.03 and 1.7 cm À3 , and their masses between 80 and 10 4 M , although uncertainties in the sizes of the clouds, their possible extension beyond the region explored, and the presence of denser gas embedded in the larger clouds imply that these will tend to be lower limits. We have clearly identified clumps of denser gas immersed in the lowdensity gas in one of the clouds; these clumps show internal H i + H 2 densities of order 50 cm À3 . Although we are not able to detect any interstellar Na i within 70 pc, the sizes of some of the clouds imply that their near edges are within that range of distances from the Sun.With respect to the local standard of rest the clouds move with velocities between 19 and 54 km s À1 . Their velocity vectors do not support the view of a local interstellar medium uniquely dominated by expansion from centers in the Scorpio-Centaurus OB association; our results suggest that this expansion is present in the Galactic center hemisphere but in the Galactic anticenter hemisphere is restricted to the immediate neighborhood of the Sun.

show abstract

Section: No 2 2003mentioning

confidence: 51%

Section: Kinematical Picture Of the Interstellar Gas In The Volume Obmentioning

confidence: 72%

Section: Clouds Ag3 Ag6 and The Pleiades Wakementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Kinematical Structure of the Local Interstellar Medium: The Galactic Anticenter Hemisphere

Genova

Beckman

2003

ASTROPHYS J SUPPL S

View full text Add to dashboard Cite

show abstract

“…They found column densities intermediate between diffuse and dark clouds, and concluded that Merope is indeed much less opaque than typical Taurus clouds. White (1984) studied a larger area in the Pleiades enclosing the main exciting stars and estimated densities n ∼ 400 cm −3 , whereas Gordon & Arny (1984) found n ∼ 100 cm −3 in a similar area. Ritchey et al (2006) obtained even lower values of n ∼ 46, 16, and 40 cm −3 in the lines of sight of 25 Tau, 27 Tau, and 28 Tau, respectively.…”

Section: Pleiades Environment and Physical Conditionsmentioning

confidence: 99%

DETECTION OF ANOMALOUS MICROWAVE EMISSION IN THE PLEIADES REFLECTION NEBULA WITHWILKINSON MICROWAVE ANISOTROPY PROBEAND THE COSMOSOMAS EXPERIMENT

Génova-Santos

Rebolo

Rubiño-Martín

et al. 2011

ApJ

View full text Add to dashboard Cite

We present evidence for anomalous microwave emission (AME) in the Pleiades reflection nebula, using data from the seven-year release of the Wilkinson Microwave Anisotropy Probe and from the COSMOSOMAS (Cosmological Structures on Medium Angular Scales) experiment. The flux integrated in a 1• radius around R.A. = 56.• 24, decl. = 23.• 78 (J2000) is 2.15 ± 0.12 Jy at 22.8 GHz, where AME is dominant. COSMOSOMAS data show no significant emission, but allow one to set upper limits of 0.94 and 1.58 Jy (99.7% confidence level), respectively, at 10.9 and 14.7 GHz, which are crucial to pin down the AME spectrum at these frequencies, and to discard any other emission mechanisms which could have an important contribution to the signal detected at 22.8 GHz. We estimate the expected level of free-free emission from an extinction-corrected Hα template, while the thermal dust emission is characterized from infrared DIRBE data and extrapolated to microwave frequencies. When we deduct the contribution from these two components at 22.8 GHz, the residual flux, associated with AME, is 2.12 ± 0.12 Jy (17.7σ ). The spectral energy distribution from 10 to 60 GHz can be accurately fitted with a model of electric dipole emission from small spinning dust grains distributed in two separated phases of molecular and atomic gas, respectively. The dust emissivity, calculated by correlating the 22.8 GHz data with 100 μm data, is found to be 4.36 ± 0.17 μK (MJy sr −1 ) −1 , a value considerably lower than in typical AME clouds, which present emissivities of ∼20 μK (MJy sr −1 ) −1 , although higher than the 0.2 μK (MJy sr −1 ) −1 of the translucent cloud LDN 1780, where AME has recently been claimed. The physical properties of the Pleiades nebula, in particular its low extinction A V ∼ 0.4, indicate that this is indeed a much less opaque object than those where AME has usually been studied. This fact, together with the broad knowledge of the stellar content of this region, provides an excellent testbed for AME characterization in physical conditions different from those generally explored up to now.

show abstract

Kinematical structure of the local interstellar medium

Genova

Beckman

Álamo

The Local Bubble and Beyond Lyman-Spitzer-Colloquium

View full text Add to dashboard Cite

An H I cloud in the Pleiades - A cloud-cluster collision?

Cited by 12 publications

References 0 publications

Kinematical Structure of the Local Interstellar Medium: The Galactic Anticenter Hemisphere

Kinematical Structure of the Local Interstellar Medium: The Galactic Anticenter Hemisphere

DETECTION OF ANOMALOUS MICROWAVE EMISSION IN THE PLEIADES REFLECTION NEBULA WITHWILKINSON MICROWAVE ANISOTROPY PROBEAND THE COSMOSOMAS EXPERIMENT

Kinematical structure of the local interstellar medium

Contact Info

Product

Resources

About