Context. Recent XMM-Newton observations have revealed that IRAS 17020+4544 is a very unusual example of black hole wind-produced feedback by a moderately luminous AGN in a spiral galaxy. Aims. Since ...the source is known to be a radio emitter, we investigated the presence and the properties of a non-thermal component. Methods. We observed IRAS 17020+4544 with the Very Long Baseline Array at 5, 8, 15, and 24 GHz within a month of the 2014 XMM-Newton observations. We further analysed archival data taken in 2000 and 2012. Results. We detect the source at 5 GHz and on short baselines at 8 GHz. At 15 and 24 GHz, the source is below our baseline sensitivity for fringe fitting, indicating a lack of prominent compact features. The morphology is that of an asymmetric double, with significant diffuse emission. The spectrum between 5 and 8 GHz is rather steep (S(ν) ~ ν− (1.0 ± 0.2)). Our reanalysis of the archival data at 5 and 8 GHz provides results consistent with the new observations, suggesting that flux density and structural variability are not important in this source. We put a limit on the separation speed between the main components of <0.06c. Conclusions. IRAS 17020+4544 shows interesting features of several classes of objects: its properties are typical of compact steep spectrum sources, low power compact sources, and radio-emitting narrow line Seyfert 1 galaxies. However, it cannot be classified in any of these categories, and remains a one-of-a-kind object.
Abstract
NGC 7469 is a well-known luminous infrared galaxy, with a circumnuclear star formation ring (∼830 pc radius) surrounding a Seyfert 1 active galactic nucleus (AGN). Nuclear unresolved winds ...were previously detected in X-rays and ultraviolet, as well as an extended biconical outflow in infrared coronal lines. We search for extended outflows by measuring the kinematics of the H
β
and O
iii
λ
5007 optical emission lines, in data of the Very Large Telescope/Multi-unit Spectroscopic Explorer integral field spectrograph. We find evidence of two outflow kinematic regimes: one slower regime extending across most of the star formation (SF) ring—possibly driven by the massive SF—and a faster regime (with a maximum velocity of −715 km s
−1
), only observed in O
iii
, in the western region between the AGN and the massive star-forming regions of the ring, likely AGN-driven. This work shows a case where combined AGN/SF feedback can be effectively spatially resolved, opening up a promising path toward a deeper understanding of feedback processes in the central kiloparsec of AGN.
We report on the measurement of the all-particle cosmic ray energy spectrum with the High Altitude Water Cherenkov (HAWC) Observatory in the energy range 10 to 500 TeV. HAWC is a ground-based ...air-shower array deployed on the slopes of Volcan Sierra Negra in the state of Puebla, Mexico, and is sensitive to gamma rays and cosmic rays at TeV energies. The data used in this work were taken over 234 days between June 2016 and February 2017. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introducing quality cuts to isolate events with shower cores landing on the array, the reconstructed energy distribution is unfolded iteratively. The measured all-particle spectrum is consistent with a broken power law with an index of −2.49±0.01 prior to a break at (45.7±0.1) TeV, followed by an index of −2.71±0.01. The spectrum also represents a single measurement that spans the energy range between direct detection and ground-based experiments. As a verification of the detector response, the energy scale and angular resolution are validated by observation of the cosmic ray Moon shadow’s dependence on energy.
We report results from multi-epoch (2006-2013) X-ray observations of the polar-scattered Seyfert 1 galaxy ESO 323-G77. The source exhibits remarkable spectral variability from months to years ...timescales. The observed spectral variability is entirely due to variations of the column density of a neutral absorber towards the intrinsic nuclear continuum. The column density is generally Compton-thin ranging from a few times 1022 cm−2 to a few times 1023 cm−2. However, one observation reveals a Compton-thick state with column density of the order of 1.5 × 1024 cm−2. The observed variability offers a rare opportunity to study the properties of the X-ray absorber(s) in an active galaxy. We identify variable X-ray absorption from two different components, namely (i) a clumpy torus whose individual clumps have a density of ≤1.7 × 108 cm−3 and an average column density of ∼4 × 1022 cm−2, and (ii) the broad-line region (BLR), comprising individual clouds with density of 0.1-8 × 109 cm−3 and column density of 1023-1024 cm−2. The derived properties of the clumpy torus can also be used to estimate the torus half-opening angle, which is of the order of 47°. We also confirm the previously reported detection of two highly ionized warm absorbers with outflow velocities of 1000-4000 km s−1. The observed outflow velocities are consistent with the Keplerian/escape velocity at the BLR. Hence, the warm absorbers may be tentatively identified with the warm/hot intercloud medium which ensures that the BLR clouds are in pressure equilibrium with their surroundings. The BLR line-emitting clouds may well be the cold, dense clumps of this outflow, whose warm/hot phase is likely more homogeneous, as suggested by the lack of strong variability of the warm absorber(s) properties during our monitoring.
We report on the coexistence of powerful gas outflows observed in millimeter and X-ray data of the radio-loud narrow-line Seyfert 1 Galaxy IRAS 17020+4544. Thanks to the large collecting power of the ...Large Millimeter Telescope (LMT), a prominent line arising from the 12CO(1-0) transition was revealed in recent observations of this source. The complex profile is composed by a narrow double-peak line and a broad wing. While the double-peak structure may be arising in a disk of molecular material, the broad wing is interpreted as the signature of a massive outflow of molecular gas with an approximate bulk velocity of −660 km s−1. This molecular wind is likely associated to a multi-component X-ray ultra-fast outflow with velocities reaching up to ∼ 0.1c and column densities in the range 1021-23.9 cm−2 that was reported in the source prior to the LMT observations. The momentum load estimated in the two gas phases indicates that within the observational uncertainties the outflow is consistent with being propagating through the galaxy and sweeping up the gas while conserving its energy. This scenario, which has been often postulated as a viable mechanism of how active galactic nucleus (AGN) feedback takes place, has so far been observed only in ultraluminous infrared galaxy sources. IRAS 17020+4544 with bolometric and infrared luminosity, respectively, of 5 × 1044 erg s−1 and 1.05 × 1011 L appears to be an example of AGN feedback in a NLSy1 Galaxy (a low power AGN). New proprietary multi-wavelength data recently obtained on this source will allow us to corroborate the proposed hypothesis.
ABSTRACT
We present the first systematic study of the molecular gas and star formation efficiency in a sample of ten narrow-line Seyfert 1 galaxies selected to have X-ray Ultra Fast Outflows and, ...therefore, to potentially show AGN feedback effects. CO observations were obtained with the IRAM 30-m telescope in six galaxies and from the literature for four galaxies. We derived the stellar mass, star formation rate, AGN, and FIR dust luminosities by fitting the multi-band spectral energy distributions with the CIGALE code. Most of the galaxies in our sample lie above the main sequence (MS), and the molecular depletion time is one to two orders of magnitude shorter than the one typically measured in local star-forming galaxies. Moreover, we found a promising correlation between the star formation efficiency and the Eddington ratio, as well as a tentative correlation with the AGN luminosity. The role played by the AGN activity in the regulation of star formation within the host galaxies of our sample remains uncertain (little or no effect? positive feedback?). Nevertheless, we can conclude that quenching by the AGN activity is minor and that star formation will likely stop in a short time due to gas exhaustion by the current starburst episode.
Abstract
The Galactic Halo is a key target for indirect dark matter detection. The High Altitude Water Cherenkov (HAWC) observatory is a high-energy (∼300 GeV to >100 TeV) gamma-ray detector located ...in central Mexico. HAWC operates via the water Cherenkov technique and has both a wide field of view of ∼ 2 sr and a >95% duty cycle, making it ideal for analyses of highly extended sources. We made use of these properties of HAWC and a new background-estimation technique optimized for extended sources to probe a large region of the Galactic Halo for dark matter signals. With this approach, we set improved constraints on dark matter annihilation and decay between masses of 10 and 100 TeV. Due to the large spatial extent of the HAWC field of view, these constraints are robust against uncertainties in the Galactic dark matter spatial profile.
Local dwarf spheroidal galaxies (dSphs) are nearby dark-matter dominated systems, making them excellent targets for searching for gamma rays from particle dark matter interactions. If dark matter ...annihilates or decays directly into two gamma rays (or a gamma ray and a neutral particle), a monochromatic spectral line is created. At TeV energies, no other process is predicted to produce spectral lines, making this a very clean indirect dark matter search channel. With the development of event-by-event energy reconstruction, we can now search for spectral lines with the High Altitude Water Cherenkov (HAWC) Observatory. HAWC is a wide field of view survey instrument located in central Mexico that observes gamma rays from ∼ 200 GeV to ∼ 200 TeV . In this work we present results from a recent search for spectral lines from local, dark matter dominated, dwarf galaxies using 1038 days of HAWC data. We also present updated limits on several continuum channels that were reported in a previous publication. Our gamma-ray spectral line limits are the most constraining obtained so far from 20 TeV to 100 TeV.
We report on the long- and short-term X-ray spectral analysis of the polar-scattered Seyfert 1.2 galaxy ESO 323−G77, observed in three epochs between 2006 and 2013 with Chandra and XMM–Newton. Four ...high-resolution Chandra observations give us a unique opportunity to study the properties of the absorbers in detail, as well as their short time-scale (days) variability. From the rich set of absorption features seen in the Chandra data, we identify two warm absorbers with column densities and ionizations that are consistent with being constant on both short and long time-scales, suggesting that those are the signatures of a rather homogeneous and extended outflow. A third absorber, ionized to a lesser degree, is also present and it replaces the strictly neutral absorber that is ubiquitously inferred from the X-ray analysis of obscured Compton-thin sources. This colder absorber appears to vary in column density on long time-scales, suggesting a non-homogeneous absorber. Moreover, its ionization responds to the nuclear luminosity variations on time-scales as short as a few days, indicating that the absorber is in photoionization equilibrium with the nuclear source on these time-scales. All components are consistent with being co-spatial and located between the inner and outer edges of the so-called dusty, clumpy torus. Assuming co-spatiality, the three phases also share the same pressure, suggesting that the warm / hot phases confine the colder, most likely clumpy, medium. We discuss further the properties of the outflow in comparison with the lower resolution XMM–Newton data.
Abstract
Ton 34 recently transitioned from non-absorbing quasar into a broad absorption line quasi-stellar object. Here, we report new HST-STIS observations of this quasar. Along with C iv ...absorption, we also detect absorption by NV+Lyα and possibly O vi+Lyβ. We follow the evolution of the C iv BAL, and find that, for the slower outflowing material, the absorption trough varies little (if at all) on a rest-frame time-scale of ∼2 yr. However, we detect a strong deepening of the absorption in the gas moving at larger velocities (−20 000 to −23 000 km s−1). The data is consistent with a multistreaming flow crossing our line of sight to the source. The transverse velocity of the flow should be ∼ few thousand km s−1, similar to the rotation velocity of the BLR gas (≈2 600 km s−1). By simply assuming Keplerian motion, these two components must have similar locations, pointing to a common outflow forming the BLR and the BAL. We speculate that BALs, mini-BALs and NALs are part of a common, ubiquitous, accretion-disc outflow in AGN, but become observable depending on the viewing angle towards the flow. The absorption troughs suggest a wind covering only ∼20 per cent of the emitting source, implying a maximum size of 10−3 pc for the clouds forming the BAL/BLR medium. This is consistent with constraints of the BLR clouds from X-ray occultations. Finally, we suggest that the low excitation broad emission lines detected in the spectra of this source lie beyond the wind, and this gas is probably excited by the shock of the BAL wind with the surrounding medium.
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