Discovery of Water Maser Emission in Eight AGNs with 70 m Antennas of NASA’s Deep Space Network

Kondratko, P. T.; Greenhill, L. J.; Moran, J. M.; Lovell, J. E. J.; Kuiper, T. B. H.; Jauncey, D. L.; Cameron, L. B.; Gómez, José F.; Garcı́a-Miró, C.; Moll, Eugene; Gregorio‐Monsalvo, I. de; Jiménez‐Bailón, E.

doi:10.1086/498641

Cited by 65 publications

(72 citation statements)

References 39 publications

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“…References.-(1) Greenhill et al 2007, in preparation; (2) ; (3) Molendi et al 2003;(18) Kondratko et al 2006b;(19) Guainazzi et al 2005;(20) Kondratko et al 2005; (21) Iyomoto et al 2001;(22) Braatz et al 1996;(23) Argon et al 2007, and references therein; (24) Fruscione et al 2005;(25) this paper. …”

Section: Comparison With Other H 2 O Disk Maser Host Galaxiesmentioning

confidence: 96%

A Deep 0.3–10 keV Spectrum of the H₂O Maser Galaxy IC 2560

Tilak

Greenhill

Done

et al. 2008

ApJ

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We present a new XMM-Newton spectrum of the Seyfert 2 nucleus of IC 2560, which hosts H 2 O maser emission from an inclined Keplerian accretion disk. The X-ray spectrum shows soft excess due to multitemperature ionized plasma, a hard continuum, and strong emission features, from Mg, Si, S, Ca, Fe, and Ni, mainly due to fluorescence. It is consistent with reflection of the continuum from a mostly neutral medium and obscuration due to a high column density, >10 24 cm À2 . The amplitude of the reflected component may exceed 10% of the central unobscured luminosity. This is higher than the reflected fraction of a few percent observed in other Seyfert 2 sources such as NGC 4945. We observe an emission line at 6.7 keV, possibly due to Fe xxv, undetected in previous Chandra observations. The absorption column density associated with this line is less than 10 23 cm À2 , which is lower than the obscuration of the central source. We hypothesize that this highly ionized Fe line emission originates in warm gas, which is also responsible for a scattered component of continuum emission that may dominate the spectrum between 1 and 3 keV. We compare X-ray and maser emission characteristics of IC 2560 and other AGNs that exhibit water maser emission originating in disk structures around central engines. The temperature for the region of the disk associated with maser action is consistent with the expected 400Y1000 K range. The clumpiness of disk structures (inferred from the maser distribution) may depend on the unobscured luminosities of the central engines.

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Section: Comparison With Other H 2 O Disk Maser Host Galaxiesmentioning

confidence: 96%

A Deep 0.3–10 keV Spectrum of the H₂O Maser Galaxy IC 2560

Tilak

Greenhill

Done

et al. 2008

ApJ

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“…It remains unclear if fuelling purely via stellar mass-loss is appropriate for systems that are likely to be accreting material in the cold phase (e.g. Lonsdale et al 2003;Kondratko et al 2006;Nenkova et al 2008). The cause of this delay could also be dynamical in nature.…”

Section: T I M E D E L Ay I N T H E O N S E T O F Ag N a N D I M P L mentioning

confidence: 99%

The triggering of local AGN and their role in regulating star formation

Kaviraj

Shabala

Deller

et al. 2015

Mon. Not. R. Astron. Soc.

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We explore the processes that trigger local AGN and the role of these AGN in regulating star formation, using ∼550 nearby galaxies observed by the mJy Imaging VLBA Exploration at 20 cm (mJIVE) survey. The 10 7 K brightness temperature required for an mJIVE detection cannot be achieved via star formation alone, allowing us to unambiguously detect nearby radio AGN and study their role in galaxy evolution. Radio AGN are an order of magnitude more common in early-type galaxies (ETGs) than in their late-type counterparts. The VLBI-detected ETGs in this study have a similar stellar mass distribution to their undetected counterparts, are typically not the central galaxies of clusters and exhibit merger fractions that are significantly higher than in the average ETG. This suggests that these radio AGN (which have VLBI luminosities >10 22 W Hz −1 ) are primarily fuelled by mergers, and not by internal stellar mass-loss or cooling flows. Our radio AGN are a factor of ∼3 times more likely to reside in the UV-optical red sequence than the average ETG. Furthermore, typical AGN lifetimes (a few 10 7 yr) are much shorter than the transit times from blue cloud to red sequence (∼1.5 Gyr). This indicates that nearby (merger-triggered) AGN appear several dynamical time-scales into the associated star formation episode. This implies that such AGN typically couple only to residual gas, at a point where star formation has already declined significantly, and are, therefore, unlikely to play a significant role in regulating the star formation episode.

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“…With their exceptional luminosities, far surpassing those of any galactic maser, these molecular lighthouses are termed "megamasers". Among AGN maser sources, a large portion (∼40%) has been identified as disk maser candidates (Kondratko et al 2006;Zhang et al 2010). Their maser spots are located within the central few pc, forming parts of a molecular accretion disk around the nuclear engine.…”

Section: Introductionmentioning

confidence: 99%

Radio properties of H₂O maser host galaxies

Zhang¹,

Henkel²,

Guo³

et al. 2012

A&A

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The 6 cm and 20 cm radio continuum properties of all 85 galaxies with reported 22 GHz H 2 O maser emission and luminosity distance D > 0.5 Mpc are studied. For the total of 55 targets for which both 6 cm and 20 cm measurements exist and for the subsample of 42 sources with masers related to active galactic nuclei (AGN), a spectral index could be determined from an assumed power-law dependence. The mean value of the resulting spectral index is in both cases 0.66 ± 0.07 (S ∝ ν −α ; S : flux density, ν: frequency). Comparing radio properties of the maser galaxies with a sample of Seyferts without detected H 2 O maser, we find that (1) the spectral indices agree within the error limits; and (2) maser host galaxies have higher nuclear radio continuum luminosities, exceeding those of the comparison sample by factors of order 5. Only considering the subsample of galaxies with masers associated with AGN, there seems to be a trend toward rising maser luminosity with nuclear radio luminosity (both at 6 cm and 20 cm). However, when accounting for the Malmquist effect, the correlation weakens to a level, which is barely significant. Overall, the study indicates that nuclear radio luminosity is a suitable indicator to guide future AGN maser searches and to enhance detection rates, which are otherwise quite low (<10%).

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Discovery of Water Maser Emission in Eight AGNs with 70 m Antennas of NASA’s Deep Space Network

Cited by 65 publications

References 39 publications

A Deep 0.3–10 keV Spectrum of the H₂O Maser Galaxy IC 2560

A Deep 0.3–10 keV Spectrum of the H₂O Maser Galaxy IC 2560

The triggering of local AGN and their role in regulating star formation

Radio properties of H₂O maser host galaxies

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Discovery of Water Maser Emission in Eight AGNs with 70 m Antennas of NASA’s Deep Space Network

Cited by 65 publications

References 39 publications

A Deep 0.3–10 keV Spectrum of the H2O Maser Galaxy IC 2560

A Deep 0.3–10 keV Spectrum of the H2O Maser Galaxy IC 2560

The triggering of local AGN and their role in regulating star formation

Radio properties of H2O maser host galaxies

Contact Info

Product

Resources

About

A Deep 0.3–10 keV Spectrum of the H₂O Maser Galaxy IC 2560

A Deep 0.3–10 keV Spectrum of the H₂O Maser Galaxy IC 2560

Radio properties of H₂O maser host galaxies