H I in nearby low-luminosity QSO host galaxies

Fazeli

Eckart

et al. 2016

A&A

We present near-infrared (NIR) H + K-band long-slit spectra of eleven galaxies that were obtained with SOFI at the NTT (ESO). The galaxies are chosen from the low-luminosity type-1 quasi-stellar object (LLQSO) sample, which comprises the 99 closest (z ≤ 0.06) QSOs from the Hamburg/ESO survey for bright UV-excess QSOs. These objects are ideal targets to study the gap between local Seyfert galaxies and high-redshift quasars because they show much stronger AGN activity than local objects, but are still close enough for a detailed structural analysis. We fit hydrogen recombination, molecular hydrogen, and [Fe ii] lines after carefully subtracting the continuum emission. From the broad Paα components, we estimated black hole masses and enlarged the sample of LLQSOs that deviate from the M BH −L bulge relations of inactive galaxies from 12 to 16 objects. All objects show emission from hot dust (T ∼ 1200 K) as well as stellar contribution. However, the respective fractions vary strongly among the objects. More than half of the objects show H 2 emission lines, which indicate a large reservoir of molecular gas that is needed to feed the AGN and star formation. In the NIR diagnostic diagram all objects lie in the location of AGN-dominated objects. However, most of the objects show indications of star formation activity, suggesting that their offset location with respect to M BH -L bulge relations of inactive galaxies may be a consequence of overluminous bulges.

Section: Introductionmentioning

confidence: 99%

A low-luminosity type-1 QSO sample

Fazeli

Eckart

et al. 2016

A&A

“…The redshift-magnitude diagram shows that the selected galaxies lie below the commonly used division line of M B = −21.5 + 5 log h 0 between QSOs and Seyfert galaxies. Several galaxies from the LLQSO sample have been observed in molecular gas (CO, Bertram et al 2007), atomic hydrogen (H , König et al 2009), and H 2 O-maser-emission (König et al 2012). Fischer et al (2006) studied nine galaxies in the NIR, focusing on spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

A low-luminosity type-1 QSO sample

Zuther

Valencia-S.

et al. 2014

A&A

Self Cite

Recognizing the properties of the host galaxies of quasi-stellar objects (QSOs) is essential for understanding the suspected coevolution of central supermassive black holes (BHs) and their host galaxies. Low-luminosity type-1 QSOs (LLQSOs) are ideal targets because of their small cosmological distance, which allows for a detailed structural analysis. We selected a subsample of the Hamburg/ESO survey for bright UV-excess QSOs that contains only the 99 nearest QSOs with redshift z ≤ 0.06. From this LLQSO sample, we observed 20 galaxies and performed aperture photometry and bulge-disk-decomposition with BUDDA on near-infrared J-, H-, and K-band images to separate disk, bulge, bar, and nuclear component. From the photometric decomposition of these 20 objects and visual inspection of images of another 26, we find that ∼50% of the hosts are disk galaxies and most of them (86%) are barred. Stellar masses, calculated from parametric models based on inactive galaxy colors, range from 2 × 10 9 M to 2 × 10 11 M with an average mass of 7 × 10 10 M . Black hole masses measured from single-epoch spectroscopy range from 1 × 10 6 M to 5 × 10 8 M with a median mass of 3 × 10 7 M . In comparison with higher-luminosity QSO samples, LLQSOs tend to have lower stellar and BH masses. Moreover, in the effective radius vs. mean surface-brightness projection of the fundamental plane, they lie in the transition area between luminous QSOs and normal galaxies. This can be seen as additional evidence that they populate a region intermediate between the local Seyfert population and luminous QSOs at higher redshift. This region has not been well studied so far. Eleven LLQSOs, for which we have reliable morphological decompositions and BH mass estimations, lie below the published BH mass vs. bulge luminosity relations for inactive galaxies. This can partially be explained if one assumes that the bulges of active galaxies contain much younger stellar populations than the bulges of inactive galaxies. Another possibility would be that their BHs are undermassive. This might indicate that the growth of the host spheroid precedes that of the BH.

“…The H  mass has been measured from observations with the Effelsberg 100m-telescope and is (6.6 ± 0.6) × 10 9 M (König et al 2009). …”

Section: Introductionmentioning

confidence: 99%

A low-luminosity type-1 QSO sample

Smajić

Scharwächter

et al. 2015

A&A

Circumnuclear star formation and active galactic nucleus (AGN) feedback is believed to play a critical role in galaxy evolution. The low-luminosity quasi-stellar object (LLQSO) sample that contains 99 of the closest AGN with redshift z ≤ 0.06 fills the gap between the local AGN population and high-redshift QSOs that is essential to understand the AGN evolution with redshift. In this paper, we present the results of the near-infrared H-and K-integral field spectroscopy of the inner kiloparsecs of the LLQSO HE 1029-1831 with SINFONI. Line maps show that ionized hydrogen gas is located in spiral arms within the stellar bar and in a circumnuclear ring. Line fluxes and diagnostic line ratios indicate recent or ongoing star formation in the circumnuclear region and the presence of young and intermediate-age stellar populations in the bulge. In particular, we find traces of an intense starburst in the circumnuclear region that has begun around 100 Myr ago but has declined to a fraction of the maximum intensity now. We estimate the dynamical bulge mass and find that the galaxy follows published M BH −M bulge relations. However, bulge-disk decomposition of the K-band image with B reveals that HE 1029-1831 does not follow the M BH −L bulge relations of inactive galaxies. We conclude that the deviation from M BH −L bulge relations of inactive galaxies in this source is instead caused by young stellar populations and not by an undermassive black hole.