A Measurement of the Hubble Constant by the Megamaser Cosmology Project

Braatz, J. A.; Condon, J. J.; Henkel, C.; Greene, Jenny E.; Lo, Fred K. Y.; Reid, M. J.; Pesce, Dominic W.; Gao, F.; Impellizzeri, C. M. V.; Kuo, C. Y.; Zhao, Wei; Constantin, Anca; Hao, Lei; Litzinger, E.

doi:10.1017/s1743921317010249

Cited by 15 publications

(20 citation statements)

References 9 publications

(13 reference statements)

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“…;Mrk 1419: Impellizzeri et al, in prep. ), and 13 maser disks were used to measure the SMBH mass (M SMBH , see Kuo et al 2011;Braatz et al 2015a;Gao et al 2017). As mentioned before, the distances measured by the MCP are among the most accurate measurements, but they are only available for three sources in our sample.…”

Section: Samplementioning

confidence: 99%

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Radio continuum of galaxies with H₂O megamaser disks: 33 GHz VLA data

Kamali

Henkel

Brunthaler

et al. 2017

A&A

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Context. Galaxies with H 2 O megamaser disks are active galaxies in whose edge-on accretion disks 22 GHz H 2 O maser emission has been detected. Because their geometry is known, they provide a unique view into the properties of active galactic nuclei. Aims. The goal of this work is to investigate the nuclear environment of galaxies with H 2 O maser disks and to relate the maser and host galaxy properties to those of the radio continuum emission of the galaxy. Methods. The 33 GHz (9 mm) radio continuum properties of 24 galaxies with reported 22 GHz H 2 O maser emission from their disks are studied in the context of the multiwavelength view of these sources. The 29-37 GHz Ka-band observations are made with the Jansky Very Large Array in B, CnB, or BnA configurations, achieving a resolution of ∼ 0.2 -0.5 arcseconds. Hard X-ray data from the Swift/BAT survey and 22 µm infrared data from WISE, 22 GHz H 2 O maser data and 1.4 GHz data from NVSS and FIRST surveys are also included in the analysis. Results. Eighty-seven percent (21 out of 24) galaxies in our sample show 33 GHz radio continuum emission at levels of 4.5 -240 σ. Five sources show extended emission (deconvolved source size larger than 2.5 times the major axis of the beam), including one source with two main components and one with three main components. The remaining detected 16 sources (and also some of the above-mentioned targets) exhibit compact cores within the sensitivity limits. Little evidence is found for extended jets (>300 pc) in most sources. Either they do not exist, or our chosen frequency of 33 GHz is too high for a detection of these supposedly steep spectrum features. In only one source among those with known maser disk orientation, NGC 4388, did we find an extended jet-like feature that appears to be oriented perpendicular to the H 2 O megamaser disk. NGC 2273 is another candidate whose radio continuum source might be elongated perpendicular to the maser disk. Smaller 100-300 pc sized jets might also be present, as is suggested by the beam-deconvolved morphology of our sources. Whenever possible, central positions with accuracies of 20-280 mas are provided. A correlation analysis shows that the 33 GHz luminosity weakly correlates with the infrared luminosity. The 33 GHz luminosity is anticorrelated with the circular velocity of the galaxy. The black hole masses show stronger correlations with H 2 O maser luminosity than with 1.4 GHz, 33 GHz, or hard X-ray luminosities. Furthermore, the inner radii of the disks show stronger correlations with 1.4 GHz, 33 GHz, and hard X-ray luminosities than their outer radii, suggesting that the outer radii may be affected by disk warping, star formation, or peculiar density distributions.

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Section: Samplementioning

confidence: 99%

“…The MCP has provided precise measures of the M SMBH for 13 galaxies Braatz et al 2015a;Gao et al 2017). In Fig.…”

Section: Black Hole Massesmentioning

confidence: 99%

Radio continuum of galaxies with H₂O megamaser disks: 33 GHz VLA data

Kamali

Henkel

Brunthaler

et al. 2017

A&A

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“…The overall detection rate in large maser surveys is rather low (e.g. Braatz et al 1997;Greenhill et al 2003a;van den Bosch et al 2016) and is about 3% for sources observed within the MCP, which mainly targets galaxies selected from large optical surveys, such as SDSS, 6dF, and 2MRS (Braatz et al 2015; see also Greenhill et al 2003b;Zhu et al 2011). Hagiwara et al (2002Hagiwara et al ( , 2003 selected their targets based on the ratio of radio continuum to IR (60 µ and 100 µ) flux densities from IRAS galaxies and obtained a slightly higher detection rate of 8%.…”

Section: Introductionmentioning

confidence: 99%

Water megamaser emission in hard X-ray selected AGN

Panessa

Castangia

Malizia³

et al. 2020

A&A

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Context. Water megamaser emission at 22 GHz has proven to be a powerful tool for astrophysical studies of active galactic nuclei (AGN) because it allows an accurate determination of the mass of the central black hole and of the accretion disc geometry and dynamics. However, after searches among thousands of galaxies, only about 200 of them have shown such spectroscopic features, most of them of uncertain classification. In addition, the physical and geometrical conditions under which a maser activates are still unknown. Aims. We characterize the occurrence of water maser emission in an unbiased sample of AGN by investigating the relation with the X-ray properties and the possible favourable geometry that is required to detect water maser. Methods. We searched for 22 GHz maser emission in a hard X-ray selected sample of AGN, taken from the INTEGRAL/IBIS survey above 20 keV. Only half of the 380 sources in the sample have water maser data. We also considered a volume-limited sub-sample of 87 sources, for which we obtained new observations with the Green Bank and Effelsberg telescopes (for 35 sources). We detected one new maser and increased its radio coverage to 75%. Results. The detection rate of water maser emission in the total sample is 15 ± 3%. This fraction increases to 19 ± 5% for the complete sub-sample, especially when we consider type 2 (22 ± 5% and 31 ± 10% for the total and complete samples, respectively) and Compton-thick AGN (56 ± 18% and 50 ± 35% for the total and complete samples, respectively). No correlation is found between water maser and X-ray luminosity. We note that all types of masers (disc and jet) are associated with hard X-ray selected AGN. Conclusions. These results demonstrate that the hard X–ray selection may significantly enhance the maser detection efficiency over comparably large optical or infrared surveys. A possible decline in detection fraction with increasing luminosity might suggest that an extremely luminous nuclear environment does not favour maser emission. The large fraction of CT AGN with water maser emission could be explained in terms of geometrical effects. The maser medium would then be the very edge-on portion of the obscuring medium.

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“…The overall detection rate in large maser surveys is rather low (e.g. Braatz et al 1997;Greenhill et al 2003;Van den Bosch et al 2016) and is about 3% for sources observed within the MCP, which mainly targets galaxies selected from large optical surveys, such as SDSS, 6dF, and 2MRS (Braatz et al 2015; see also Greenhill et al 2003;Zhu et al 2011). Hagiwara et al (2002; selected their targets based on the ratio of radio continuum to IR (60 µ and 100 µ) flux densities from IRAS galaxies and obtained a slightly higher detection rate of 8%.…”

Section: Introductionmentioning

confidence: 99%

Water maser emission in hard X-ray selected AGN

et al. 2017

View full text Add to dashboard Cite

Context. Water megamaser emission at 22 GHz has proven to be a powerful tool for astrophysical studies of active galactic nuclei (AGN) because it allows an accurate determination of the mass of the central black hole and of the accretion disc geometry and dynamics. However, after searches among thousands of galaxies, only about 200 of them have shown such spectroscopic features, most of them of uncertain classification. In addition, the physical and geometrical conditions under which a maser activates are still unknown. Aims. We characterize the occurrence of water maser emission in an unbiased sample of AGN by investigating the relation with the X-ray properties and the possible favourable geometry that is required to detect water maser. Methods. We searched for 22 GHz maser emission in a hard X-ray selected sample of AGN, taken from the INTEGRAL/IBIS survey above 20 keV. Only half of the 380 sources in the sample have water maser data. We also considered a volume-limited sub-sample of 87 sources, for which we obtained new observations with the Green Bank and Effelsberg telescopes (for 35 sources). We detected one new maser and increased its radio coverage to 75%. Results. The detection rate of water maser emission in the total sample is 15±3%. This fraction increases to 19±5% for the complete sub-sample, especially when we consider type 2 (22±5% and 31±10% for the total and complete samples, respectively) and Comptonthick AGN (56±18% and 50±35% for the total and complete samples, respectively). No correlation is found between water maser and X-ray luminosity. We note that all types of masers (disc and jet) are associated with hard X-ray selected AGN.Conclusions. These results demonstrate that the hard X-ray selection may significantly enhance the maser detection efficiency over comparably large optical or infrared surveys. A possible decline in detection fraction with increasing luminosity might suggest that an extremely luminous nuclear environment does not favour maser emission. The large fraction of CT AGN with water maser emission could be explained in terms of geometrical effects. The maser medium would then be the very edge-on portion of the obscuring medium.

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A Measurement of the Hubble Constant by the Megamaser Cosmology Project

Cited by 15 publications

References 9 publications

Radio continuum of galaxies with H₂O megamaser disks: 33 GHz VLA data

Radio continuum of galaxies with H₂O megamaser disks: 33 GHz VLA data

Water megamaser emission in hard X-ray selected AGN

Water maser emission in hard X-ray selected AGN

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A Measurement of the Hubble Constant by the Megamaser Cosmology Project

Cited by 15 publications

References 9 publications

Radio continuum of galaxies with H2O megamaser disks: 33 GHz VLA data

Radio continuum of galaxies with H2O megamaser disks: 33 GHz VLA data

Water megamaser emission in hard X-ray selected AGN

Water maser emission in hard X-ray selected AGN

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Product

Resources

About

Radio continuum of galaxies with H₂O megamaser disks: 33 GHz VLA data

Radio continuum of galaxies with H₂O megamaser disks: 33 GHz VLA data