Evidence for ionized hydrogen in the cores of globular clusters

Grindlay, J.; Liller, W.

doi:10.1086/182521

Cited by 12 publications

(8 citation statements)

References 5 publications

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“…Barmby et al (2009) derive M ICM upper limits of 0.04 − 1.4 M from dust mass upper limits. These upper limits are (with the exception of M2) consistent with observed M ICM values from Freire et al (2001, and Grindlay & Liller (1977). We collect the four reported M ICM measurements in Table 1, along with other useful GC parameters and timescales we derive.…”

Section: Application To Galactic Clusterssupporting

confidence: 71%

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Clearing the Gas From Globular Clusters and Dwarf Spheroidals With Classical Novae

Moore¹,

Bildsten²

2011

ApJ

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Observations of the intra-cluster medium (ICM) in galactic globular clusters (GCs) show a systematic deficiency in ICM mass as compared to that expected from accumulation of stellar winds in the time available between galactic plane crossings. In this paper, we reexamine the original hypothesis of Scott and Durisen that hydrogen-rich explosions on accreting white dwarfs, classical novae (CNe), will sweep out the ICM from the cluster more frequently than galactic plane crossings. From the CNe rate and stellar mass-loss rate, this clearing mechanism predicts that ≈ 0.03 M should be present in ≤ 10 5 M GCs. We model the expanding remnant made from the 10 −4 M nova ejecta and show that it escapes long before it has cooled. We discuss the few positive ICM measurements and use a Monte-Carlo simulation of the accumulation and CNe recurrence times to reveal the possible variance in the ICM masses for the higher mass (> 5 × 10 5 M ) GCs. We find that nova shells are effective at clearing the ICM in low-mass GCs (≤ 10 5 M ), whereas higher-mass clusters may experience a quiescent time between novae long enough to prevent the next nova shell from escaping. The nova clearing mechanism will also operate in ultra-faint Milky Way satellites, where many upper limits on gas masses are available.

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Section: Application To Galactic Clusterssupporting

confidence: 71%

“…There have been few positive ICM measurements in GCs. Barmby et al (2009) Grindlay & Liller (1977). We collect the four reported M ICM measurements in Table 1, along with other useful GC parameters and timescales we derive.…”

Section: Application To Galactic Clustersmentioning

confidence: 99%

Clearing the Gas From Globular Clusters and Dwarf Spheroidals With Classical Novae

Moore¹,

Bildsten²

2011

ApJ

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“…Our inferred limits on the gas mass are consistent with the results of previous searches for intra-cluster neutral and ionized hydrogen, as summarized in Roberts (1988). Two clusters have reported detections of ionized gas: NGC 104 (Freire et al 2001) and NGC 1851 (Grindlay & Liller 1977). Freire et al (2001) derived a total gas mass of 0.1M ⊙ and stated that they expected essentially all the gas in the cluster to be ionized; Grindlay & Liller (1977) estimated the total mass of ionized hydrogen in NGC 1851 as 0.02M ⊙ .…”

Section: Dust Masses and Limitsmentioning

confidence: 99%

“…Two clusters have reported detections of ionized gas: NGC 104 (Freire et al 2001) and NGC 1851 (Grindlay & Liller 1977). Freire et al (2001) derived a total gas mass of 0.1M ⊙ and stated that they expected essentially all the gas in the cluster to be ionized; Grindlay & Liller (1977) estimated the total mass of ionized hydrogen in NGC 1851 as 0.02M ⊙ . Our gas mass upper limit for NGC 104 is about the same as the Freire et al (2001) detection while our upper limit for NGC 1851 is above the Grindlay & Liller (1977) level.…”

Section: Dust Masses and Limitsmentioning

confidence: 99%

ASPITZERSEARCH FOR COLD DUST WITHIN GLOBULAR CLUSTERS

Barmby¹,

Boyer²,

Woodward³

et al. 2008

The Astronomical Journal

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Globular cluster stars evolving off the main sequence are known to lose mass, and it is expected that some of the lost material should remain within the cluster as an intracluster medium (ICM). Most attempts to detect such an ICM have been unsuccessful. The Multiband Imaging Photometer for Spitzer on the Spitzer Space Telescope was used to observe eight Galactic globular clusters in an attempt to detect the thermal emission from ICM dust. Most clusters do not have significant detections at 70 µm; one cluster, NGC 6341, has tentative evidence for the presence of dust, but 90 µm observations do not confirm the detection. Individual 70 µm point sources which appear in several of the cluster images are likely to be background galaxies. The inferred dust mass and upper limits are < 4 × 10 −4 M ⊙ , well below expectations for cluster dust production from mass loss in red and asymptotic giant branch stars. This implies that either globular cluster dust production is less efficient, or that ICM removal or dust destruction is more efficient, than previously believed. We explore several possibilities for ICM removal and conclude that present data do not yet permit us to distinguish between them.

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“…Hot stars such as blue horizontal branch stars or post‐AGB stars produce a radiation field with T rad > 10 000 K, which might ionize the ICM. Searches for free–free continuum or Hα line emission have set limits of M gas ∼ 1 M ⊙ (Smith, Hesser & Shawl 1976; Faulkner & Freeman 1977; Grindlay & Liller 1977; Hesser & Shawl 1977; Knapp et al 1996: Very Large Array (VLA), 8.4 GHz). On the other hand, the presence of a population of free electrons in 47 Tuc is inferred from pulsar timing observations (Freire et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Stellar mass loss and the intracluster medium in Galactic globular clusters: a deep radio survey for H i and OH

Loon

Stanimirović

Evans

et al. 2006

Monthly Notices of the Royal Astronomical Society

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We present the results of a survey, the deepest to date, for H i emission at 21 cm and OH emission at 18 cm (lines at 1612, 1665, 1667 and 1720 MHz) in the direction towards the Galactic globular clusters M15, M2, NGC 6934, NGC 7006 and Pal 13. The aim is to measure the amount of hydrogen in the intracluster medium, and to find OH masers in the circumstellar envelopes of globular cluster red giants. We present a tentative detection of 0.3 M⊙ of neutral hydrogen in M15 and possible detections of neutral hydrogen in M2 and Pal 13. We derive upper limits to the neutral hydrogen content of NGC 6934 and 7006. No OH emission is detected. We also present deep H i data of the northern tip of the Magellanic Stream behind Pal 13.

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Evidence for ionized hydrogen in the cores of globular clusters

Cited by 12 publications

References 5 publications

Clearing the Gas From Globular Clusters and Dwarf Spheroidals With Classical Novae

Clearing the Gas From Globular Clusters and Dwarf Spheroidals With Classical Novae

ASPITZERSEARCH FOR COLD DUST WITHIN GLOBULAR CLUSTERS

Stellar mass loss and the intracluster medium in Galactic globular clusters: a deep radio survey for H i and OH

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