Resolving the Nuclear Radio Emission from M32 with the Very Large Array

Peng, Sijia; Li, Zhiyuan; Sjouwerman, Loránt O.; Yang, Yang; Xie, Fu-Guo; Yuan, Feng

doi:10.3847/1538-4357/ab855d

Cited by 8 publications

(6 citation statements)

References 47 publications

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“…A similar radio structure is seen in the nucleus of the earlytype dwarf galaxy M32, which lacks core radio emission but has extended emission on a spatial scale of ∼10 pc, inferred to be synchrotron emission from AGN outflows interacting with the ISM (Peng et al 2020). NGC 404 also shows extended radio emission on a spatial scale >10 pc, but unlike NGC 5102 and M32, the radio continuum emission is centrally peaked, consistent with core emission and hence current jet activity (Nyland et al 2017).…”

Section: Agn Outflowsmentioning

confidence: 55%

X-Ray and Radio Observations of Central Black Holes in Nearby Low-mass Early-type Galaxies: Preliminary Evidence for Low Eddington Fractions

Urquhart¹,

McDermott²,

Strader³

et al. 2022

ApJ

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We present new radio and X-ray observations of two nearby (<4 Mpc) low-mass early-type galaxies with dynamically confirmed central black holes: NGC 5102 and NGC 205. NGC 5102 shows a weak nuclear X-ray source and has no core radio emission. However, for the first time we demonstrate that it shows luminous extended radio continuum emission in low-resolution, low-frequency (<3 GHz) data, consistent with jet lobes on scales ≳100 pc formed from past accretion and jet activity. By contrast, in new, extremely deep, strictly simultaneous Very Large Array and Chandra observations, no radio or X-ray emission is detected from the black hole in NGC 205. We consider these measurements and upper limits in the context of the few other low-mass early-type galaxies with dynamically confirmed black holes, and show that the mean ratio of bolometric to Eddington luminosity in this sample is only log ( L bol / L Edd ) = − 6.57 ± 0.50 . These Eddington ratios are lower than typical in a comparison sample of more massive early-type galaxies, though this conclusion is quite tentative due to our small sample of low-mass galaxies and potential biases in the comparison sample. This preliminary result is in mild tension with previous work using less sensitive observations of more distant galaxies, which predict higher X-ray luminosities than we observe for low-mass galaxies. If it is confirmed that central black holes in low-mass galaxies typically have low Eddington ratios, this presents a challenge to measuring the occupation fraction of central black holes with standard optical emission line, X-ray, or radio surveys.

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Section: Agn Outflowsmentioning

confidence: 55%

X-Ray and Radio Observations of Central Black Holes in Nearby Low-mass Early-type Galaxies: Preliminary Evidence for Low Eddington Fractions

Urquhart¹,

McDermott²,

Strader³

et al. 2022

ApJ

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“…When considering only the X-ray selected AGN, the AGN fraction in low-mass compact galaxies is 0.1% (1/937), which is of the same order as that of X-ray selected AGN in dwarf galaxies at z 0.3 (∼0.4%; Mezcua et al 2018a;Birchall et al 2020). Adding the weakly accreting SMBHs already published for the cE M32 (Peng et al 2020) and the UCDs M60-UCD1, M59-UCD3, and NGC7727-Nuc 2 (Schweizer et al 2018), the AGN fraction amongst compact galaxies rises to 1.6% (15/937).…”

Section: Agn Fractionmentioning

confidence: 62%

A search for active galactic nuclei in low-mass compact galaxies

Ferre-Mateu,

Mezcua,

Barrows

2021

Preprint

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Low-mass compact galaxies (ultracompact dwarfs -UCDs-and compact ellipticals -cEs-) populate the stellar size-mass plane between globular clusters and early-type galaxies. Known to be formed either in-situ with an intrinsically low mass or resulting from the stripping of a more massive galaxy, the presence of a supermassive or an intermediate-mass black hole (BH) could help discriminate between these possible scenarios. With this aim, we have performed a multiwavelength search of active BH activity, i.e. active galactic nuclei (AGN), in a sample of 937 low-mass compact galaxies (580 UCDs and 357 cEs). This constitutes the largest study of AGN activity in these types of galaxies. Based on their X-ray luminosity, radio luminosity and morphology, and/or optical emission line diagnostic diagrams, we find a total of 11 cEs that host an AGN. We also study for the first time the location of both low-mass compact galaxies (UCDs and cEs) and dwarf galaxies hosting AGN on the BH-galaxy scaling relations, finding that low-mass compact galaxies tend to be overmassive in the BH mass-stellar mass plane but not as much in the BH mass-stellar velocity dispersion correlation. This, together with available BH mass measurements for some of the low-mass compact galaxies, supports a stripping origin for the majority of these objects that would contribute to the scatter seen at the low-mass end of the BH-galaxy scaling relations. However, the differences are too large to be explained solely by this scatter, and thus our results suggest that a flattening at such low-masses is also plausible, happening at a velocity dispersion of ∼20-40 km s−1.

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“…The radio Ho et al 2003). The radio luminosity is 2.5 × 10 32 erg s −1 based on VLA B array 6.6 GHz observations (Yang et al 2015) and 10 32 erg s −1 based on VLA A array 6 GHz observations (Peng et al 2020) that probe regions of size ≈4 pc and ≈1.5 pc, respectively. The X-ray luminosity is 7.9 × 10 35 erg s −1 based on Chandra observations (Ho et al 2003).…”

Section: The Fundamental Plane Of Black Hole Activitymentioning

confidence: 99%

Radio Observations of Four Active Galactic Nuclei Hosting Intermediate-mass Black Hole Candidates: Studying the Outflow Activity and Evolution

Yang

Mohan²,

Yang

et al. 2022

ApJ

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Observational searches for intermediate-mass black holes (IMBHs; 102–106 M ⊙) include relatively isolated dwarf galaxies. For those that host active galactic nuclei (AGNs), the IMBH nature may be discerned through the accretion–jet activity. We present radio observations of four AGN-hosting dwarf galaxies, which potentially harbor IMBHs. Very large array (VLA) observations indicate steep spectra (indices of −0.63 to −1.05) between 1.4 and 9 GHz. However, a comparison with the 9 GHz in-band spectral index shows a steepening for GH047 and GH158 (implying older/relic emission) and flattening for GH106 and GH163 (implying recent activity). Overlapping emission regions in the VLA 1.4 GHz and our very long baseline array (VLBA) 1.5 GHz observations, and possibly symmetric pc-scale extensions, are consistent with recent activity in the latter two. Using the compact VLBA radio luminosity, X-ray luminosity (probing the accretion activity), and the black hole masses, all AGNs are found to lie on the empirical fundamental plane relation. The four AGNs are radio-quiet with relatively higher Eddington ratios (0.04–0.32) and resemble X-ray binaries during spectral state transitions that entail an outflow ejection. Furthermore, the radio to X-ray luminosity ratio log R X of −3.9 to −5.6 in these four sources support the scenarios that include corona mass ejection from the accretion disk and wind activity. The growth to kpc-scales likely proceeds along a similar trajectory to young AGNs and peaked spectrum sources. These complex clues can thus aid in the detection and monitoring of IMBHs in the nearby universe.

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Resolving the Nuclear Radio Emission from M32 with the Very Large Array

Cited by 8 publications

References 47 publications

X-Ray and Radio Observations of Central Black Holes in Nearby Low-mass Early-type Galaxies: Preliminary Evidence for Low Eddington Fractions

X-Ray and Radio Observations of Central Black Holes in Nearby Low-mass Early-type Galaxies: Preliminary Evidence for Low Eddington Fractions

A search for active galactic nuclei in low-mass compact galaxies

Radio Observations of Four Active Galactic Nuclei Hosting Intermediate-mass Black Hole Candidates: Studying the Outflow Activity and Evolution

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