Parkes H I observations of southern globular clusters - Implications for stellar mass loss

Smith, Graeme H.; Wood, P. R.; Faulkner, D. J.; Wright, A. E.

doi:10.1086/168603

Cited by 36 publications

(39 citation statements)

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“…Previous observations, however, suggest that the intracluster gas is also deficient in globular clusters, as mentioned in Introduction. The deficiency was also reported for NGC 5139 (Smith et al 1990). The conclusion of Tsujimoto, Shigeyama, and Suda (2007) can be altered if the intracluster gas is removed before it is accreted to the stars within the cluster.…”

Section: Impacts On the Evolution Of A Globular Clustersupporting

confidence: 57%

An AKARI Search for Intracluster Dust of Globular Clusters

Matsunaga

Mito

Nakada

et al. 2008

Publications of the Astronomical Society of Japan

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We report on observations of 12 globular clusters with the Far-Infrared Surveyor (FIS) aboard the AKARI satellite. Our goal is to search for emission from cold dust within clusters. We detected diffuse emissions toward NGC 6402 and 2808, but the IRAS 100 m maps show the presence of strong background radiation. They are likely to have been emitted from the Galactic cirrus. We also detected 28 point-like sources mainly in WIDE-S images (90 m). At least several of them are not associated with clusters, but background galaxies identified in external catalogs. We present the spectral energy distributions (SEDs) by combining near-and-mid infrared data obtained with the Infrared Camera (IRC), if possible. Those SEDs suggest that most of the point sources are background galaxies. For most of the other clusters, we have confirmed a lack of intracluster dust. We evaluated the upper limits of the intracluster dust mass to be between 10 5 and 10 3 Mˇ, depending on the dust temperature. The inferred lifetime of the intracluster dust is shorter than 5 Myr (T d = 70 K) or 50 Myr (35 K). Such a short lifetime indicates some mechanism(s) are at work to remove the intracluster dust. We also discuss its impact on the chemical evolution of globular clusters.

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Section: Impacts On the Evolution Of A Globular Clustersupporting

confidence: 57%

An AKARI Search for Intracluster Dust of Globular Clusters

Matsunaga

Mito

Nakada

et al. 2008

Publications of the Astronomical Society of Japan

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“…The case for an ICM origin for features A-D is strengthened by our discovery of an unreported H i cloud near the velocity of ω Cen (Figure 18) in public data from the H i Parkes AllSky Survey (HIPASS; Barnes et al 2001), which may have also been detected by Smith et al (1990) in earlier observations. The center of this H i feature is not spatially coincident with any of the dust features, but rather lies ≈15 to the southeast of the cluster center, just on the edge of the coverage of our MIPS mosaic ( Figure 15).…”

Section: The Intracluster Mediummentioning

confidence: 73%

ASPITZER SPACE TELESCOPEATLAS OF ω CENTAURI: THE STELLAR POPULATION, MASS LOSS, AND THE INTRACLUSTER MEDIUM

Boyer

McDonald

Loon

et al. 2008

The Astronomical Journal

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We present a Spitzer Space Telescope imaging survey of the most massive Galactic globular cluster, ω Centauri, and investigate stellar mass loss at low metallicity and the intracluster medium (ICM). The survey covers approximately 3.2× the cluster half-mass radius at 3.6, 4.5, 5.8, 8, and 24 µm, resulting in a catalog of over 40,000 point sources in the cluster. Approximately 140 cluster members ranging 1.5 dex in metallicity show a red excess at 24 µm, indicative of circumstellar dust. If all of the dusty sources experience mass loss, the cumulative rate of loss is estimated at 2.9-4.2 ×10 −7 M yr −1 , 63%-66% of which is supplied by three asymptotic giant branch stars at the tip of the red giant branch (RGB). There is little evidence for strong mass loss lower on the RGB. If this material had remained in the cluster center, its dust component ( 1 × 10 −4 M ) would be detectable in our 24 and 70 µm images. While no dust cloud located at the center of ω Cen is apparent, we do see four regions of very faint, diffuse emission beyond two half-mass radii at 24 µm. It is unclear whether these dust clouds are foreground emission or are associated with ω Cen. In the latter case, these clouds may be the ICM in the process of escaping from the cluster.

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“…However, efforts to obtain evidence of intracluster matter have been largely unsuccessful: diffuse gas in GCs was detected only as an upper limit and well below 1 M Based on observations collected at the European Southern Observatory, Chile, during FLAMES Science Verification. (Roberts 1988;Smith et al 1990;Faulkner & Smith 1991;Freire et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Modelling chromospheric line profiles in NGC 2808: evidence of mass loss from RGB stars

Mauas

Cacciari

Pasquini

2006

A&A

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In this study we test the possibility that the asymmetry in the profiles of the Hα and Ca ii K lines in red giant stars is due to the presence of an active chromosphere rather than to mass loss. To this end, we compare line profiles computed using relevant model chromospheres to profiles of the Hα and Ca ii K lines observed in five red giant stars of the globular cluster NGC 2808. The spectra were taken with FLAMES during the science verification, using the UVES mode at high resolution (R = 43 000) for the Hα line, and GIRAFFE in MEDUSA mode (R = 20 000) for the Ca ii K line. We find that the observed profiles are better described if a negative (outward) velocity field is included in the model chromospheres. This leads to mass loss rates of a few 10 −9 M yr −1 , so very close to the requirements of the stellar evolution theory.

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Parkes H I observations of southern globular clusters - Implications for stellar mass loss

Cited by 36 publications

References 0 publications

An AKARI Search for Intracluster Dust of Globular Clusters

An AKARI Search for Intracluster Dust of Globular Clusters

ASPITZER SPACE TELESCOPEATLAS OF ω CENTAURI: THE STELLAR POPULATION, MASS LOSS, AND THE INTRACLUSTER MEDIUM

Modelling chromospheric line profiles in NGC 2808: evidence of mass loss from RGB stars

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