scholarly journals The quasar feedback survey: discovering hidden Radio-AGN and their connection to the host galaxy ionized gas

2021 ◽  
Vol 503 (2) ◽  
pp. 1780-1797
Author(s):  
M E Jarvis ◽  
C M Harrison ◽  
V Mainieri ◽  
D M Alexander ◽  
F Arrigoni Battaia ◽  
...  
Keyword(s):  
Radio Emission ◽  
Host Galaxy ◽  
Radio Luminosity ◽  
Host Galaxies ◽  
Coronal Emission ◽  
Ionized Gas ◽  
Infrared Excess ◽  
Very Large Array ◽  
Extended Radio ◽  
Spatially Extended

ABSTRACT We present the first results from the Quasar Feedback Survey, a sample of 42 z < 0.2, [O iii] luminous AGNs ( L[O III] > 1042.1 ergs s−1) with moderate radio luminosities (i.e. L1.4GHz > 1023.4 W Hz−1; median L1.4GHz = 5.9 × 1023 W Hz−1). Using high spatial resolution (∼0.3–1 arcsec), 1.5–6 GHz radio images from the Very Large Array, we find that 67 per cent of the sample have spatially extended radio features on ∼1–60 kpc scales. The radio sizes and morphologies suggest that these may be lower radio luminosity versions of compact, radio-loud AGNs. By combining the radio-to-infrared excess parameter, spectral index, radio morphology, and brightness temperature, we find radio emission in at least 57 per cent of the sample that is associated with AGN-related processes (e.g. jets, quasar-driven winds, or coronal emission). This is despite only 9.5–21 per cent being classified as radio-loud using traditional criteria. The origin of the radio emission in the remainder of the sample is unclear. We find that both the established anticorrelation between radio size and the width of the [O   iii] line, and the known trend for the most [O iii] luminous AGNs to be associated with spatially extended radio emission, also hold for our sample of moderate radio luminosity quasars. These observations add to the growing evidence of a connection between the radio emission and ionized gas in quasar host galaxies. This work lays the foundation for deeper investigations into the drivers and impact of feedback in this unique sample.

scholarly journals WATCAT: a tale of wide-angle tailed radio galaxies

2019 ◽  
Vol 626 ◽  
pp. A8 ◽  
Author(s):  
V. Missaglia ◽  
F. Massaro ◽  
A. Capetti ◽  
M. Paolillo ◽  
R. P. Kraft ◽  
...  
Keyword(s):  
Radio Galaxies ◽  
Sloan Digital Sky Survey ◽  
Host Galaxy ◽  
Wide Angle ◽  
Host Galaxies ◽  
Very Large Array ◽  
Sky Survey ◽  
Black Hole Masses ◽  
Extended Emission ◽  
Radio Power

We present a catalog of 47 wide-angle tailed radio galaxies (WATs), the WATCAT, mainly built including a radio morphological classification; WATs were selected by combining observations from the National Radio Astronomy Observatory/Very Large Array Sky Survey (NVSS), the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST), and the Sloan Digital Sky Survey (SDSS). We included in the catalog only radio sources showing two-sided jets with two clear “warmspots” (i.e., jet knots as bright as 20% of the nucleus) lying on the opposite side of the radio core, and having classical extended emission resembling a plume beyond them. The catalog is limited to redshifts z ≤ 0.15, and lists only sources with radio emission extended beyond 30 kpc from the host galaxy. We found that host galaxies of WATCAT sources are all luminous (−20.5 ≳ Mr ≳ −23.7), red early-type galaxies with black hole masses in the range 108 ≲ MBH ≲ 109 M⊙. The spectroscopic classification indicates that they are all low-excitation galaxies (LEGs). Comparing WAT multifrequency properties with those of FR I and FR II radio galaxies at the same redshifts, we conclude that WATs show multifrequency properties remarkably similar to FR I radio galaxies, having radio power of typical FR IIs.

scholarly journals The radio properties of high-excitation radio galaxies with intermediate radio powers

2020 ◽  
Vol 494 (2) ◽  
pp. 2053-2067
Author(s):  
J C S Pierce ◽  
C N Tadhunter ◽  
R Morganti
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
High Sensitivity ◽  
Seyfert Galaxies ◽  
Radio Galaxies ◽  
Host Galaxy ◽  
High Excitation ◽  
Power Sources ◽  
Very Large Array ◽  
Extended Radio

ABSTRACT In the past decade, high-sensitivity radio surveys have revealed that the local radio active galactic nucleus population is dominated by moderate-to-low power sources with emission that is compact on galaxy scales. High-excitation radio galaxies (HERGs) with intermediate radio powers (22.5 < log (L1.4 GHz) < 25.0 W Hz−1) form an important sub-group of this population, since there is strong evidence that they also drive multiphase outflows on the scales of galaxy bulges. Here, we present high-resolution Very Large Array observations at 1.5, 4.5, and 7.5 GHz of a sample of 16 such HERGs in the local universe (z < 0.1), conducted in order to investigate the morphology, extent, and spectra of their radio emission in detail, down to sub-kpc scales. We find that the majority (56 per cent) have unresolved structures at the limiting angular resolution of the observations (∼0.3 arcsec). Although similar in the compactness of their radio structures, these sources have steep radio spectra and host galaxy properties that distinguish them from local low-excitation radio galaxies that are unresolved on similar scales. The remaining sources exhibit extended radio structures with projected diameters ∼1.4–19.0 kpc and a variety of morphologies: three double-lobed; two large-scale diffuse; one jetted and ‘S-shaped’; one undetermined. Only 19 per cent of the sample therefore exhibit the double-lobed/edge-brightened structures often associated with their counterparts at high and low radio powers: radio-powerful HERGs and Seyfert galaxies, respectively. Additional high-resolution observations are required to investigate this further, and to probe the ≲300 pc scales on which some Seyfert galaxies show extended structures.

scholarly journals Velocity Offsets Due to Mass Outflows in Active Galaxies

2009 ◽  
Vol 5 (S267) ◽  
pp. 387-392
Author(s):  
D. M. Crenshaw ◽  
S. B. Kraemer ◽  
H. R. Schmitt ◽  
R. F. Mushotzky ◽  
J. P. Dunn
Keyword(s):  
Seyfert Galaxies ◽  
Emission Lines ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Ionized Gas ◽  
Ngc 4151 ◽  
Spatially Resolved ◽  
Mass Outflow ◽  
Ngc 1068 ◽  
Narrow Emission

AbstractWe present a study of the radial velocity offsets between AGN-related narrow emission lines and host-galaxy emission and absorption lines in Seyfert galaxies with observed redshifts less than 0.043. We find that 35% of the Seyferts in the sample show [O iii] emission lines with blueshifts with respect to their host galaxies exceeding 50 km s−1, whereas only 6% show redshifts this large, in qualitative agreement with most previous studies. We also find that a greater percentage of Seyfert 1 galaxies show blueshifts than Seyfert 2 galaxies. Using HST/STIS spatially-resolved spectra of the Seyfert 2 galaxy NGC 1068 and the Seyfert 1 galaxy NGC 4151, we generate geometric models of their narrow-line regions (NLRs) and inner galactic disks and show how these models can explain the blueshifted [O iii] emission lines in collapsed STIS spectra of these two Seyferts. We conclude that the combination of mass outflow of ionized gas in the NLR and extinction by dust in the inner disk (primarily in the form of dust spirals) is primarily responsible for the velocity offsets in Seyfert galaxies.

scholarly journals Fundamental differences in the radio properties of red and blue quasars: enhanced compact AGN emission in red quasars

2020 ◽  
Vol 494 (4) ◽  
pp. 4802-4818 ◽  
Author(s):  
V A Fawcett ◽  
D M Alexander ◽  
D J Rosario ◽  
L Klindt ◽  
S Fotopoulou ◽  
...  
Keyword(s):  
Star Formation ◽  
Radio Emission ◽  
Sloan Digital Sky Survey ◽  
Formation Processes ◽  
Very Large Array ◽  
Radio Detection ◽  
Extended Radio ◽  
Sky Survey ◽  
Tentative Evidence ◽  
Insight Into

ABSTRACT We have recently used the Faint Images of the Radio Sky at Twenty-centimeters (FIRST) survey to show that red quasars have fundamentally different radio properties to typical blue quasars: a significant (factor ≈3) enhancement in the radio-detection fraction, which arises from systems around the radio-quiet threshold with compact (<5 arcsec) radio morphologies. To gain greater insight into these physical differences, here we use the DR14 Sloan Digital Sky Survey (SDSS) and more sensitive, higher resolution radio data from the Very Large Array (VLA) Stripe 82 (S82) and VLA-COSMOS 3 GHz (C3GHz) surveys. With the S82 data, we perform morphological analyses at a resolution and depth three times that of the FIRST radio survey, and confirm an enhancement in radio-faint and compact red quasars over typical quasars; we now also find tentative evidence for an enhancement in red quasars with slightly extended radio structures (16–43 kpc at z = 1.5). These analyses are complemented by C3GHz, which is deep enough to detect radio emission from star-formation processes. From our data we find that the radio enhancement from red quasars is due to AGN activity on compact scales (≲43 kpc) for radio-intermediate–radio-quiet sources (−5 < $\mathcal {R}$ < −3.4, where $\mathcal {R}$ = $L_{\rm{1.4\,GHz}}/L_{6\mu\text{m}}$), which decreases at $\mathcal {R}$ < −5 as the radio emission from star-formation starts to dilute the AGN component. Overall our results argue against a simple orientation scenario and are consistent with red quasars representing a younger, earlier phase in the overall evolution of quasars.

scholarly journals Quasar activity in the neighbor Universe

2012 ◽  
Vol 8 (S295) ◽  
pp. 268-268
Author(s):  
R. Falomo ◽  
D. Bettoni ◽  
K. Karhunen ◽  
J. Kotilainen ◽  
M. Uslenghi
Keyword(s):  
Black Hole ◽  
Radio Emission ◽  
Absolute Magnitude ◽  
Host Galaxy ◽  
Black Hole Mass ◽  
Host Galaxies ◽  
Preliminary Results ◽  
Galaxy Model ◽  
The Mean

AbstractWe investigate the properties of the galaxies hosting quasars in ~400 low redshift (z < 0.5) SDSS QSO that are in the “Stripe 82” sky area. For this region deep (r ~ 22.4 mag) u, b, v, r and i images are available and allow us to study both the host galaxies and the Mpc scale environments. This sample outnumbers previous studies of low-z QSOs. We present preliminary results of the properties of quasars activity and in particular we focus on the relationships among host galaxy luminosity, black hole mass, radio emission and the surrounding galaxy environments. We select from the SDSS - QSO Catalogue all the QSOs in the range of redshift 0.1<z<0.5 and in the Stripe82 region. This gives a total of 416 QSO. In this sample we are dominated by radio quiet quasars (about 5% are radio loud). In Fig. 1 we report the distribution of QSO in the plane redshift-MR (H0 = 70). The mean redshift of the sample is <z> = 0.39 and the average absolute magnitude is: <Mi> = −22.68. We implemented an automated procedure using AIDA (Uslenghi & Falomo 2011) to decompose the QSO images into nucleus and host galaxy luminosity. After masking of all contaminating sources in the field a 2D fitting is performed using PSF + galaxy model. In Fig. 1 we show an example of a QSO image in the sample and the distribution of the host galaxy absolute magnitude of the resolved objects.

scholarly journals Through the kaleidoscope: star formation the host galaxies of radio-AGN

2013 ◽  
Vol 9 (S304) ◽  
pp. 323-326
Author(s):  
Marios Karouzos ◽  
Myungshin Im ◽  
Markos Trichas ◽  
Tomo Goto ◽  
Matt Malkan ◽  
...  
Keyword(s):  
Star Formation ◽  
Feedback Mechanism ◽  
Host Galaxy ◽  
Radio Sources ◽  
Radio Luminosity ◽  
Powerful Radio ◽  
Host Galaxies ◽  
Radio Jets ◽  
The North ◽  
Multi Wavelength

AbstractThere exist strong evidence supporting the co-evolution of central supermassive black holes and their host galaxies; however it is still under debate how such a relation comes about and whether it is relevant for all or only a subset of galaxies. A rich multi-wavelength dataset is available for the North Ecliptic Pole field, most notably surveyed by the AKARI infrared space telescope. We investigate the star-formation properties of the host galaxies of radio-AGN together with the radio feedback mechanism, potentially responsible for the eventual quenching of star formation. Using broadband SED modelling, the nuclear and host galaxy components of these sources are studied as a function of their radio luminosity. Here we present results concerning the AGN content of the radio sources in this field, while offering evidence supporting a “maintenance” type of feedback from powerful radio-jets.

scholarly journals The ATESP 5 GHz radio survey

2018 ◽  
Vol 621 ◽  
pp. A19
Author(s):  
R. Ricci ◽  
I. Prandoni ◽  
H. R. De Ruiter ◽  
P. Parma
Keyword(s):  
High Resolution ◽  
Radio Emission ◽  
Radio Galaxies ◽  
Host Galaxy ◽  
Radio Sources ◽  
Early Type ◽  
Host Galaxies ◽  
Star Forming ◽  
Open Questions ◽  
5 Ghz

Aims. It is now established that the faint radio population is a mixture of star-forming galaxies and faint active galactic nuclei (AGNs), with the former dominating below S1.4 GHz ∼ 100μJy and the latter at larger flux densities. The faint radio AGN component can itself be separated into two main classes, mainly based on the host-galaxy properties: sources associated with red/early-type galaxies (like radio galaxies) are the dominant class down to ∼100 μJy; quasar/Seyfert–like sources contribute an additional 10–20%. One of the major open questions regarding faint radio AGNs is the physical process responsible for their radio emission. This work aims at investigating this issue, with particular respect to the AGN component associated with red/early-type galaxies. Such AGNs show, on average, flatter radio spectra than radio galaxies and are mostly compact (≤30 kpc in size). Various scenarios have been proposed to explain their radio emission. For instance they could be core/core-jet dominated radio galaxies, low-power BL Lacertae, or advection-dominated accretion flow (ADAF) systems. Methods. We used the Australia Telescope Compact Array (ATCA) to extend a previous follow-up multi-frequency campaign to 38 and 94 GHz. This campaign focuses on a sample of 28 faint radio sources associated with early-type galaxies extracted from the ATESP 5 GHz survey. Such data, together with those already at hand, are used to perform radio spectral and variability analyses. Both analyses can help us to disentangle between core- and jet-dominated sources, as well as to verify the presence of ADAF/ADAF+jet systems. Additional high-resolution observations at 38 GHz were carried out to characterise the radio morphology of these sources on kiloparsec scales. Results. Most of the sources (25/28) were detected at 38 GHz, while only one (ATESP5J224547−400324) of the twelve sources observed at 94 GHz was detected. From the analysis of the radio spectra we confirmed our previous findings that pure ADAF models can be ruled out. Only eight out of the 28 sources were detected in the 38-GHz high-resolution (0.6 arcsec) radio images and of those eight only one showed a tentative core-jet structure. Putting together spectral, variability, luminosity, and linear size information we conclude that different kinds of sources compose our AGN sample: (a) luminous and large (≥100 kpc) classical radio galaxies (∼18% of the sample); (b) compact (confined within their host galaxies), low-luminosity, power-law (jet-dominated) sources (∼46% of the sample); and (c) compact, flat (or peaked) spectrum, presumably core-dominated, radio sources (∼36% of the sample). Variability is indeed preferentially associated with the latter.

scholarly journals Unveiling the weak radio quasar population at $z\ge 4$

2019 ◽  
Vol 490 (2) ◽  
pp. 2542-2549 ◽  
Author(s):  
Krisztina Perger ◽  
Sándor Frey ◽  
Krisztina É Gabányi ◽  
L Viktor Tóth
Keyword(s):  
Radio Emission ◽  
Signal To Noise Ratio ◽  
High Redshift ◽  
Formation Rate ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Full Sample ◽  
Star Forming ◽  
Long Baseline ◽  
The Individual

ABSTRACT We applied image stacking on empty field Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey maps centred on optically identified high-redshift quasars at $z\ge 4$ to uncover the hidden $\mu$Jy radio emission in these active galactic nuclei (AGN). The median stacking procedure for the full sample of 2229 optically identified AGN uncovered an unresolved point source with an integrated flux density of 52 $\mu$Jy, with a signal-to-noise ratio ${\sim} 10$. We co-added the individual image centre pixels to estimate the characteristic monochromatic radio power at 1.4 GHz considering various values for the radio spectral index, revealing a radio population with $P_\mathrm{1.4\, GHz}\sim 10^{24}$ W Hz$^{-1}$. Assuming that the entire radio emission originates from star-forming (SF) activity in the nuclear region of the host galaxy, we obtained an upper limit on the characteristic star formation rate, ${\sim} 4200$ M$_\odot$ yr$^{-1}$. The angular resolution of FIRST images is insufficient to distinguish between the SF and AGN origin of radio emission at these redshifts. However, a comparison with properties of individual sources from the literature indicates that a mixed nature is likely. Future very long baseline interferometry radio observations and ultradeep Square Kilometre Array surveys are expected to be sensitive enough to detect and resolve the central $1\!-\!10$ kpc region in the host galaxies, and thus discriminate between SF and AGN related emission.

scholarly journals Compact Radio Sources in the Nuclei of Elliptical Galaxies

1972 ◽  
Vol 44 ◽  
pp. 222-223 ◽  
Author(s):  
R. D. Ekers
Keyword(s):  
Radio Emission ◽  
Angular Size ◽  
Optical Emission ◽  
Elliptical Galaxies ◽  
Emission Lines ◽  
Radio Sources ◽  
Radio Luminosity ◽  
Compact Source ◽  
Extended Radio

Ten percent of the intrinsically bright elliptical galaxies contain compact radio sources (angular size < 3 arc sec) with radio luminosity ∼ 1040 erg s−1. The presence of a compact source is correlated with the presence of extended radio emission and with the presence of optical emission lines.

scholarly journals Massive galaxies with very young AGN

2007 ◽  
Vol 3 (S245) ◽  
pp. 261-262
Author(s):  
Nathan de Vries ◽  
I. A. G. Snellen ◽  
R. T. Schilizzi ◽  
M. D. Lehnert ◽  
M. N. Bremer
Keyword(s):  
Galaxy Evolution ◽  
Radio Galaxies ◽  
Host Galaxy ◽  
Radio Sources ◽  
Host Galaxies ◽  
Nuclear Activity ◽  
Massive Galaxies ◽  
Low Level ◽  
Extended Radio ◽  
Absolute Magnitudes

AbstractGigahertz Peaked Spectrum (GPS) radio galaxies are generally thought to be the young counterparts of classical extended radio sources and live in massive ellipticals. GPS sources are vital for studying the early evolution of radio-loud AGN, the trigger of their nuclear activity, and the importance of feedback in galaxy evolution. We study the Parkes half-Jansky sample of GPS radio galaxies of which now all host galaxies have been identified and 80% has their redshifts determined (0.122 < z < 1.539). Analysis of the absolute magnitudes of the GPS host galaxies show that at z > 1 they are on average a magnitude fainter than classical 3C radio galaxies. This suggests that the AGN in young radio galaxies have not yet much influenced the overall properties of the host galaxy. However their restframe UV luminosities indicate that there is a low level of excess as compared to passive evolution models.

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