A sample of nearby galaxies hosting low-luminosity type 1 quasi-stellar objects (QSOs), previously studied in CO and HI emission lines, has been searched for maser emission. Using the Effelsberg 100-m telescope, we observed 17 sources with redshifts of z<0.06 and δ>-30° for emission in the 22 GHz water vapor maser transition. The sample objects have been drawn from a wide-angle survey for optically bright QSOs (Hamburg /ESO survey, HES). No host galaxies from the sample have been detected in the water maser emission line. In this paper we review the discussion on the reasons for water megamasers being rarely found in Seyfert 1 galaxies. Eight of them are bulge dominated and probably of elliptical type (E/S0), whereas 6 have spiral geometry. Three of the objects seem to be in a phase of merging/interaction. We found 3σ upper limits for the flux density of 27 to 60 mJy at spectral resolutions of ~0.43 km/s. We furthermore find that the viewing angle to the line of sight to the galaxy, under which the probability to detect megamaser emission is highest, is about 6°.
We present MIR sub-arcsec observations of Mrk 1383, a nearby QSO, part of a sample of nearby QSOs currently being observed with the 10.4 m Gran Telescopio de Canarias (GTC). The radial profile of the QSO is analyzed and we find that most of the MIR emission is unresolved (θ~ 0.4", 600 pc) and consistent with previous measurements from Spitzer (θ~ 4"). We derive the spectral energy distribution (SED) of the nuclear emission, relatively uncontaminated by starlight, combining measurements from the literature as a first step towards characterizing the torus parameters in this QSO.
We present the results of infrared L-band (3-4 micron) slit spectroscopy of 30 PG QSOs at z < 0.17, the representative sample of local high-luminosity, optically selected AGNs. The 3.3 micron polycyclic aromatic hydrocarbon (PAH) emission feature is used to probe nuclear (< a few kpc) starburst activity and to investigate the connections between AGNs and nuclear starbursts in PG QSOs. The 3.3 micron PAH emission is detected in the individual spectra of 5/30 of the observed PG QSOs. We construct a composite spectrum of PAH-undetected PG QSOs and discern the presence of the 3.3 micron PAH emissi…
We present observations of a population of Lya emitters (LAEs) exhibiting fluorescent emission via the reprocessing of ionizing radiation from nearby hyperluminous QSOs. These LAEs are part of a survey at redshifts 2.5 < z < 2.9 combining narrow-band photometric selection and spectroscopic follow-up to characterize the emission mechanisms, physical properties, and three-dimensional locations of the emitters with respect to their nearby hyperluminous QSOs. These data allow us to probe the radiation field, and thus the radiative history, of the QSOs, and we determine that most of the 8 QSOs in o…
We report four new 22 GHz water masers found in a Green Bank Telescope search toward 37 nearby objects. Our goal was to find new maser galaxies, AGN disk-masers, and objects where both hydroxyl and water maser species coexist. We observed 37 sources within 250 Mpc that were selected by high X-ray luminosity (L_X > 10^40 W) and high absorbing column density (N_H ~ 10^22 cm^-2). Sources also included dual or triple AGN and interacting systems. We further included objects detected in hydroxyl (OH). The selection consisted of 16 new sources, 13 previous non-detections to follow up with a factor te…
There is growing evidence that every galaxy with a considerable spheroidal component hosts a supermassive black hole (SMBH) at its center. Strong correlations between the SMBH and the spheroidal component suggest a physical connection through a coevolutionary scenario. For very massive galaxies a merger-driven scenario is preferred, resulting in elliptical galaxies. In the nearby universe, we find many disk galaxies, showing no signs of recent interaction. Alternative secular evolutionary scenarios for such galaxies involve internal triggers like bars and spiral arms or minor mergers. We analy…
An "exotic" idea proposed by Viktor Ambartsumian was that new galaxies are formed through the ejection from older active galaxies. Galaxies beget galaxies, instead of the standard scenario in which galaxies stem from the evolution of the seeds derived from fluctuations in the initial density field. This idea is in some way contained in the speculative proposal that some or all QSOs might be objects ejected by nearby galaxies, and that their redshift is not cosmological (Arp, G./M. Burbidge and others). I will discuss some of the arguments for and against this scenario; in particular, I shall t…
[abridged] We present optical integral field spectroscopy for a flux-limited sample of 19 QSOs at z<0.2 and spatially resolve their ionized gas properties at a physical resolution of 2-5kpc. The extended narrow line regions (ENLRs), photoionized by the radiation of AGN, have sizes of up to several kpc and correlate more strongly with the QSO continuum luminosity than with the integrated [OIII] luminosity. We find a relation of the form log(r)~(0.46+-0.04)log(L_5100), reinforcing the picture of an approximately constant ionization parameter for the ionized clouds across the ENLR. Besides the EN…
The low luminosity QSO (LLQSO) sample consists of type 1 active galactic nuclei (AGN) up to a redshift of z=0.06 in the Hamburg/ESO QSO survey. Its purpose is to study how the brightest AGN in the nearby universe evolve with respect to AGN activity and host properties as a function of redshift. We show that our sample lies well between the NUclei of GAlaxies (NUGA) sample and the Palomar Green (PG) QSO sample in terms of redshift, gas masses and luminosities and seems to connect them. The continuous growth in mass, luminosity and, linked to this, the AGN activity over the samples has either a …
We present mid-infrared (MIR, 7.5-13.5 $μ$m) imaging and spectroscopy observations obtained with the CanariCam (CC) instrument on the 10.4m Gran Telescopio CANARIAS for a sample of 20 nearby, MIR bright and X-ray luminous QSOs. We find that for the majority of QSOs the MIR emission is unresolved at angular scales nearly 0.3 arcsec, corresponding to physical scales $<600$ pc. We find that the higher-spatial resolution CC spectra have similar shapes to those obtained with Spitzer/IRS, and hence we can assume that the spectra are not heavily contaminated by extended emission in the host galaxy. W…
We present multi-frequency simultaneous VLBA observations at 15, 22 and 43 GHz towards the nucleus of the nearby radio galaxy NGC 1052. These three continuum images reveal a double-sided jet structure, whose relative intensity ratios imply that the jet axis is oriented close to the sky plane. The steeply rising spectra at 15-43 GHz at the inner edges of the jets strongly suggest that synchrotron emission is absorbed by foreground thermal plasma. We detected H_2O maser emission in the velocity range of 1550-1850 km/s, which is redshifted by 50-350 km/s with respect to the systemic velocity of N…
Luminous extragalactic water masers are known to be associated with AGN and have provided accurate estimates for the mass of the central supermassive black hole and the size and structure of the accretion disk in nearby galaxies. To find water masers at much higher redshifts, we have begun a survey of known gravitationally lensed quasars and star-forming galaxies. In this paper, we present a search for 22 GHz (rest frame) water masers toward five dusty, gravitationally lensed quasars and star-forming galaxies at redshifts 2.3--2.9 with the Effelsberg telescope and the EVLA. Our observations do…
Despite first being detected in the 1970s, surprisingly little is known about the OH main line maser population in the nearby starburst galaxy M82. Sometimes referred to as 'kilomasers', they have isotropic luminosities intermediate between Galactic masers and those found in more distant megamasers. Several observations have been carried by this group over the last ten years in an attempt to get a better handle on their nature. High velocity resolution VLA observations in 2006 showed that almost all of the maser spots, distributed across the central arcminute of the galaxy, were apparently coi…
Water megamasers at 22 GHz with a gas disk configuration in galaxies provide the most precise measurements of supermassive black hole masses, as well as independent constraints on the Hubble constant in the nearby universe. The existence of other maser types, such as jet or outflow masers, represents another tracer for AGN science. However, the detection rate of water megamasers in galaxies is extremely low. Over 40 years, only $\sim$ 160 galaxies are found to harbour maser emission, and $\sim$ 30\% of them show features in their maser emission that indicate a disk-like geometry. Therefore, in…
We investigate the possibility of using the ratio between the 2-10 keV flux and the [Ne V]3426 emission line flux (X/NeV) as a diagnostic diagram to discover heavily obscured, possibly Compton-Thick Active Galactic Nuclei (AGN) up to z~1.5. First, we calibrate a relation between X/NeV and the cold absorbing column density N_H using a sample of 74 bright, nearby Seyferts with both X-ray and [Ne V] data available in the literature. Similarly to what is found for the X-ray to [O III]5007 flux ratio (X/OIII), we found that the X/NeV ratio decreases towards large column densities. Essentially all l…
We have used the Australia Telescope Compact Array (ATCA) to search for emission from the $4_{-1} \rightarrow 3_{0}E$ transition of methanol (36.2 GHz) towards the center of the nearby starburst galaxy NGC253. Two regions of emission were detected, offset from the nucleus along the same position angle as the inner spiral arms. The emission is largely unresolved on a scale of 5 arcsec, has a full-width half maximum (FWHM) line width of < 30 km s$^{-1}$, and an isotropic luminosity orders of magnitude larger than that observed in any Galactic star formation regions. These characteristics suggest…
A primary goal of the SCUBA-2 Web survey is to perform tomography of the early inter-galactic medium by studying systems containing some of the brightest quasi-stellar objects (QSOs; 2.5<z<3.0) and nearby submillimetre galaxies. As a first step, this paper aims to characterize the galaxies that host the QSOs. To achieve this, a sample of 13 hyper-luminous (L_AGN>10^14 L_odot) QSOs with previous submillimetre continuum detections were followed up with CO(3-2) observations using the NOEMA interferometer. All but two of the QSOs are detected in CO(3-2); for one non-detection, our observations sho…
We present new GALEX images and optical spectroscopy of J1229+02, a dwarf post-starburst galaxy located 81 kpc from the 1585 km/s absorber in the 3C 273 sight line. The absence of Hα emission and the faint GALEX UV fluxes confirm that the galaxy's recent star formation rate is $<10^{-3} M_{\odot}$/yr. Absorption-line strengths and the UV-optical SED give similar estimates of the acceptable model parameters for its youngest stellar population where $f_m$ < 60% of its total stars (by mass) formed in a burst $t_sb$ = 0.7-3.4 Gyr ago with a stellar metallicity of -1.7 < [Fe/H] < +0.2; we also esti…
High-frequency water megamasers as precision probes of black holes, galaxies and cosmology: A case for a next-generation sub-mm/mm interferometer
New York University Abu Dhabi（阿布扎比纽约大学）；ASTRON, Netherlands Institute for Radio Astronomy（荷兰射电天文研究所）；Black Hole Initiative, Harvard University（哈佛大学黑洞倡议项目）；European Southern Observatory (ESO)（欧洲南方天文台）；University of Geneva（日内瓦大学）；National Sun Yat-Sen University（国立中山大学）；Bucknell University（巴克内尔大学）；Toyo University（东洋大学）；Institute of Astronomy and Astrophysics, Academia Sinica（中央研究院天文及天文物理研究所）；National Radio Astronomy Observatory（美国国家射电天文台）
