Finding faint intermediate-mass black holes in the radio band

Maccarone, Tom; Fender, R. P.; Tzioumis, Anastasios

doi:10.1007/1-4020-4085-7_27

Cited by 8 publications

(12 citation statements)

References 32 publications

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“…Theoretical models of the accretion of matter that has non‐zero angular momentum on to a black hole (Krumholz, McKee & Klein 2005; Proga & Begelman 2003) show a reduction of the accretion rate down to the level of a few percent of the Bondi rate. In the following, we will assume an accretion rate in the range , in agreement with Maccarone (2004) and Maccarone, Fender & Tzioumis (2005). Thus, it is possible to estimate the masses (or place upper limits thereon) of central black holes in nearby globular clusters using straightforward and relatively short radio observations.…”

Section: Detecting Imbhs Using Radio Continuum Emissionmentioning

confidence: 99%

Upper limits on the central black hole masses of 47 Tuc and NGC 6397 from radio continuum emission

Rijcke

Buyle

Dejonghe

2006

Monthly Notices of the Royal Astronomical Society: Letters

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We present upper limits on the masses of the putative central intermediate‐mass black holes in two nearby Galactic globular clusters: 47 Tuc (NGC 104), the second brightest Galactic globular cluster, and NGC 6397, a core‐collapse globular cluster and, with a distance of 2.7 kpc, quite possibly the nearest globular cluster. These upper limits are obtained using a technique suggested by T. Maccarone. These mass estimates have been derived from 3σ upper limits on the radio continuum flux at 1.4 GHz, assuming that the putative central black hole accretes the surrounding matter at a rate of between 0.1 and 1 per cent of the Bondi accretion rate. For 47 Tuc, we find a 3σ upper limit of 2060–670 M⊙, depending on the actual accretion rate of the black hole and the distance to 47 Tuc. For NGC 6397, which is closer to us, we derive a 3σ upper limit of 1290–390 M⊙. While estimating mass upper limits based on radio continuum observations requires making assumptions about the gas density and the accretion rate of the black hole, their derivation does not require complex and time‐consuming dynamical modelling. Thus, this method offers an independent way of estimating black hole masses in nearby globular clusters. If, generally, central black holes in stellar systems accrete matter faster than 0.1 per cent of the Bondi accretion rate, then these results indicate the absence of black holes in these globular clusters with masses as predicted by the extrapolated M•–σc relation.

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Section: Detecting Imbhs Using Radio Continuum Emissionmentioning

confidence: 99%

Upper limits on the central black hole masses of 47 Tuc and NGC 6397 from radio continuum emission

Rijcke

Buyle

Dejonghe

2006

Monthly Notices of the Royal Astronomical Society: Letters

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“…The difficulties of stellar dynamics have prompted a search for accretion constraints on the presence of intermediate‐mass black holes. As pointed out by Maccarone (2004) and Maccarone, Fender & Tzioumis (2005), deep radio searches may be a very effective way to detect intermediate‐mass black holes in globular clusters and related objects. Indeed, for a given X‐ray luminosity, supermassive mass black holes produce far more radio luminosity than stellar‐mass black holes.…”

Section: Introductionmentioning

confidence: 99%

“…Several methods have been considered for proving the existence of these intermediate‐mass black holes (in the 10 2 – range), but to date there is no conclusive evidence for their existence. Searches for radio emission from globular clusters have mostly yielded only upper limits (Maccarone et al 2005; De Rijcke, Buyle & Dejonghe 2006; Bash et al 2008). Although, the cluster G1 in M31 seems to have evidence for harbouring an intermediate‐mass black hole (Ulvestad, Greene & Ho 2007), including radio detection.…”

Section: Introductionmentioning

confidence: 99%

Radio observations of NGC 6388: an upper limit on the mass of its central black hole

Cseh¹,

Kaaret²,

Corbel³

et al. 2010

Monthly Notices of the Royal Astronomical Society

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We present the results of deep radio observations with the Australia Telescope Compact Array (ATCA) of the globular cluster NGC 6388. We show that there is no radio source detected (with an rms noise level of 27 μJy) at the cluster centre of gravity or at the locations of any of the Chandra X‐ray sources in the cluster. Based on the fundamental plane of accreting black holes which is a relationship between X‐ray luminosity, radio luminosity and black hole mass, we place an upper limit of ∼1500 M on the mass of the putative intermediate‐mass black hole located at the centre of NGC 6388. We discuss the uncertainties of this upper limit and the previously suggested black hole mass of based on surface density profile analysis.

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“…This mass range is estimated by using the measured Ursa Minor velocity dispersion (Wilkinson et al 2004) and by considering stellar mass-to-light ratios of ∼ 1-3 (Zaritsky et al 2006) and a dark matter virial mass ∼ 10 9 M . Maccarone et al (2005) estimated an expected X-ray luminosity of 7 × 10 34 erg s −1 for M bh = 2.3 × 10 4 M . We plot the Suzaku spectrum for an index 1.7 power law with L X = 3×10 34 erg s −1 , and an optimistic estimate of the unresolved stellar emission, along with the background-subtracted XIS0+3 spectrum of Ursa Minor in Figure 3.…”

mentioning

confidence: 99%

NEW LIMITS ON STERILE NEUTRINOS FROMSUZAKUOBSERVATIONS OF THE URSA MINOR DWARF SPHEROIDAL GALAXY

Loewenstein

Kusenko

Biermann

2009

ApJ

110

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We present results of our search for X-ray line emission associated with the radiative decay of the sterile neutrino, a well motivated dark matter candidate, in Suzaku Observatory spectra of the Ursa Minor dwarf spheroidal galaxy. These data represent the first deep observation of one of these extreme mass-to-light systems and the first dedicated dark matter search using an X-ray telescope. No such emission line is positively detected, and we place new constraints on the combination of the sterile neutrino mass, m st , and the active-sterile neutrino oscillation mixing angle, θ . Line flux upper limits are derived using a maximum-likelihood-based approach that, along with the lack of intrinsic X-ray emission, enables us to minimize systematics and account for those that remain. The limits we derive match or approach the best previous results over the entire 1-20 keV mass range from a single Suzaku observation. These are used to place constraints on the existence of sterile neutrinos with given parameters in the general case and in the case where they are assumed to constitute all of the dark matter. The range allowed implies that sterile neutrinos remain a viable candidate to make up some-or all-of the dark matter and also explain pulsar kicks and various other astrophysical phenomena.

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Finding faint intermediate-mass black holes in the radio band

Cited by 8 publications

References 32 publications

Upper limits on the central black hole masses of 47 Tuc and NGC 6397 from radio continuum emission

Upper limits on the central black hole masses of 47 Tuc and NGC 6397 from radio continuum emission

Radio observations of NGC 6388: an upper limit on the mass of its central black hole

NEW LIMITS ON STERILE NEUTRINOS FROMSUZAKUOBSERVATIONS OF THE URSA MINOR DWARF SPHEROIDAL GALAXY

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