The nuclear and extended infrared emission of the Seyfert galaxy NGC 2992 and the interacting system Arp 245
I. García-Bernete, C. Ramos Almeida, J. A. Acosta-Pulido, A. Alonso-Herrero, M. Sánchez-Portal, M. Castillo, M. Pereira-Santaella, P. Esquej, O. González-Martín… 展开作者
I. García-Bernete, C. Ramos Almeida, J. A. Acosta-Pulido, A. Alonso-Herrero, M. Sánchez-Portal, M. Castillo, M. Pereira-Santaella, P. Esquej, O. González-Martín, T. Díaz-Santos, P. Roche, S. Fisher, M. Pović, A. M. Pérez García, I. Valtchanov, C. Packham, N. A. Levenson
We present subarcsecond resolution infrared (IR) imaging and mid-IR spectroscopic observations of the Seyfert 1.9 galaxy NGC 2992, obtained with the Gemini North Telescope and the Gran Telescopio CANARIAS (GTC). The N-band image reveals faint extended emission out to ~3 kpc, and the PAH features detected in the GTC/CanariCam 7.5-13 micron spectrum indicate that the bulk of this extended emission is dust heated by star formation. We also report arcsecond resolution MIR and far-IR imaging of the interacting system Arp 245, taken with the Spitzer Space Telescope and the Herschel Space Observatory. Using these data, we obtain nuclear fluxes using different methods and find that we can only recover the nuclear fluxes obtained from the subarcsecond data at 20-25 micron, where the AGN emission dominates. We fitted the nuclear IR spectral energy distribution of NGC 2992, including the GTC/CanariCam nuclear spectrum (~50 pc), with clumpy torus models. We then used the best-fitting torus model to decompose the Spitzer/IRS 5-30 spectrum (~630 pc) in AGN and starburst components, using different starburst templates. We find that, whereas at shorter mid-IR wavelengths the starburst component dominates (64% at 6 micron), the AGN component reaches 90% at 20 micron. We finally obtained dust masses, temperatures and star formation rates for the different components of the Arp 245 system and find similar values for NGC 2992 and NGC 2993. These measurements are within those reported for other interacting systems in the first stages of the interaction.
The line and continuum spectra of the merger galaxy Arp 220 are analysed with the aim of investigating the ionizing and heating sources. We refer to radio, optical, infrared and X-ray spectra. The results show that in agreement with other merger galaxies, the optical lines are emitted from gas photoionised by the AGN and heated by the shocks in the extended NLR. The infrared lines are better explained by the emission from gas close to the starburst. The starburst dominates the infrared emission. [OI] and [CI] lines in the far-infrared are formed in the internal region of extended clouds and ar…
We present results from our Giant Metrewave Radio Telescope (GMRT) HI, Himalayan Chandra Telescope (HCT) Halpha, 1m Sampurnanand Telescope (ST) and 1.3m Devasthal Fast Optical Telescope (DFOT) deep optical observations of NGC 7805/6 (Arp 112) system to test KUG 2359+311's tidal dwarf galaxy (TDG) candidacy and explore the properties of the interacting system. Our GMRT HI map shows no HI detection associated with KUG 2359+311, nor any HI tail or bridge-like structure connecting KUG 2359+311 to the NGC 7805/6 system. Our HCT Halpha image on the other hand, shows strong detections in KUG 2359+311…
Archival WFC3/UVIS imaging of Arp 299 (NGC 3690E + NGC 3690W) is retrieved to investigate the young massive cluster (YMC) population of this ongoing merger. We extract 2182 cluster candidates, including 1323 high confidence photometric sources. Multiband photometry is matched with Yggdrasil models to estimate the age, mass, and extinction of each cluster. A Schechter fit of the truncated cluster mass function results in a characteristic mass ${\rm M_{*} = 1.6 \times 10^6 M_{\odot}}$. Our results confirm that intensely star-forming galaxies such as Arp 299 host more massive clusters than quiesc…
We used the Z-transformed Discrete Correlation Function (ZDCF) and the Stochastic Process Estimation for AGN Reverberation (SPEAR) methods for the time series analysis of the continuum and the H$α$ and H$β$ line fluxes of a sample of well known type 1 active galactic nuclei (AGNs): Arp 102B, 3C 390.3, NGC 5548, and NGC 4051, where the first two objects are showing double-peaked emission line profiles. The aim of this work is to compare the time lag measurements from these two methods, and check if there is a connection with other emission line properties. We found that the obtained time lags f…
Low frequency observations at 325 and 610 MHz have been carried out for two "radio-loud" Seyfert galaxies, NGC4235 and NGC4594 (Sombrero galaxy), using the Giant Meterwave Radio Telescope (GMRT). The 610 MHz total intensity and 325-610 MHz spectral index images of NGC4235 tentatively suggest the presence of a "relic" radio lobe, most likely from a previous episode of AGN activity. This makes NGC4235 only the second known Seyfert galaxy after Mrk6 to show signatures of episodic activity. Spitzer and Herschel infrared spectral energy distribution (SED) modelling using the clumpyDREAM code predic…
We studied the apparent galaxy pair NGC 1232 / NGC 1232A with Chandra, looking for evidence of interactions and collisions. We report that there is no cloud of diffuse emission in NGC 1232, contrary to previous claims in the literature. Instead, we find that the small "companion" galaxy NGC 1232A contains three ultraluminous X-ray sources (ULXs) with peak 0.3-10 keV luminosities above 10^{40} erg/s (assuming a cosmological distance of 93 Mpc for this galaxy). For its mass, morphology, metal abundance and bright ULX population, NGC 1232A is analogous to the more nearby late-type spiral NGC 1313…
The first detection of the silicate absorption feature in AGNs was made at 9.7 micrometer for the prototypical Seyfert 2 galaxy NGC 1068 over 30 years ago, indicating the presence of a large column of silicate dust in the line-of-sight to the nucleus. It is now well recognized that type 2 AGNs exhibit prominent silicate absorption bands, while the silicate bands of type 1 AGNs appear in emission. More recently, using the Mid-Infrared Interferometric Instrument on the Very Large Telescope Interferometer, Jaffe et al. (2004) by the first time spatially resolved the parsec-sized dust torus around…
We report on Herschel/PACS observations of absorption lines of OH+, H2O+ and H3O+ in NGC 4418 and Arp 220. Excited lines of OH+ and H2O+ with E_lower of at least 285 and \sim200 K, respectively, are detected in both sources, indicating radiative pumping and location in the high radiation density environment of the nuclear regions. Abundance ratios OH+/H2O+ of 1-2.5 are estimated in the nuclei of both sources. The inferred OH+ column and abundance relative to H nuclei are (0.5-1)x10^{16} cm-2 and \sim2x10^{-8}, respectively. Additionally, in Arp 220, an extended low excitation component around …
The latest observations of line and continuum spectra emitted from the extended narrow line region (ENLR) of the Seyfert 2 galaxy NGC 7212 are analysed using models accounting for photoionization from the active nucleus and shocks. The results show that relatively high (500--800 \kms) shock velocities appear on the edge of the cone and outside of it. The model-inferred AGN flux, which is lower than $10^{-11}$ photons cm$^{-2}$ s$^{-1}$ eV$^{-1}$ at the Lyman limit, is more typical of low-luminosity AGN, and less so for Seyfert 2 galaxies. The preshock densities are characteristic of the ENLR a…
Aims. We present new IRAM Plateau de Bure Interferometer observations of Arp 220 in HCN, HCO$^{+}$, HN$^{13}$C J=1-0, C$_{2}$H N=1-0, SiO J = 2-1, HNCO J$_{k,k'}$ = 5$_{0,4}$ - 4$_{0,4}$, CH$_{3}$CN(6-5), CS J=2-1 and 5-4 and $^{13}$CO J=1-0 and 2-1 and of NGC 6240 in HCN, HCO$^{+}$ J = 1-0 and C$_{2}$H N = 1-0. In addition, we present Atacama Large Millimeter/submillmeter Array science verification observations of Arp 220 in CS J = 4-3 and CH$_{3}$CN(10-9). Various lines are used to analyse the physical conditions of the molecular gas including the [$^{12}$CO]/[$^{13}$CO] and [$^{12}$CO]/[C$^…
We study three Arp' systems of peculiar galaxies: Arp 42 (NGC 5829), Arp 82 (NGC 2535/36) and Arp 58 (UGC 4457), using the long-slit spectral observations carried out at the 6m telescope BTA of Special Astrophysical Observatory. Arp 82 and Arp 58 are the M51-type systems. In the third system - Arp 42, there are two extremely luminous kpc-sized clumps observed at the ends of the bifurcated spiral arm, however the source of perturbations remains unknown. From the emission line measurements we analyzed the distribution of gas line-of-sight (LOS) velocity, velocity dispersion and gas-phase metalli…
We present results from high signal-to-noise optical spectropolarimetric observations of the Seyfert 1 galaxies NGC783 and Mrk509 in the 3500-7000 A range. We find complex structure in the polarized emission for both objects. In particular, Position Angle (PA) changes across the Balmer lines show a distinctive 'M'-shaped profile that had not been observed in this detail before, but could represent a common trait in Seyfert 1 galaxies. In fact, while this shape is observed in all Balmer lines in NGC3783, Mrk509 transitions into a 'M'-shaped PA profile for higher transitions lines. We have model…
New Gemini mid-infrared spectroscopic observations together with Spitzer Space telescope archival data, are used to study the properties of the dusty torus and circumnuclear star formation in the active galaxies NGC 7213 and NGC 1386. Our main conclusions can be summarised as follows. Polycyclic aromatic hydrocarbon (PAH) emission is absent in the T-ReCS nuclear spectra but is ubiquitous in the data from Spitzer at distances above 100 pc. Star formation rates surface densities are estimated from the 12.8 $μm$ [Ne{\sc ii}] line strengths leading to values close to 0.1M$_\odot\,\,{\rm yr}^{-1}\,…
We report ALMA Band 7 (350 GHz) imaging at 0.4 - 0.6arcsec resolution and Band 9 (696 GHz) at ~0.25arcsec resolution of the luminous IR galaxies Arp 220 and NGC 6240. The long wavelength dust continuum is used to estimate ISM masses for Arp 220 East, West and NGC 6240 of 1.9, 4.2 and 1.6x10^9 msun within radii of 69, 65 and 190 pc. The HCN emission was modeled to derive the emissivity distribution as a function of radius and the kinematics of each nuclear disk, yielding dynamical masses consistent with the masses and sizes derived from the dust emission. In Arp 220, the major dust and gas conc…
We present the first NuSTAR observation of a 'true' Type 2 Seyfert galaxy. The 3-40 keV X-ray spectrum of NGC3147 is characterised by a simple power-law, with a standard Γ~1.7 and an iron emission line, with no need for any further component up to ~40 keV. These spectral properties, together with significant variability on time-scales as short as weeks (as shown in a 2014 Swift monitoring campaign), strongly support an unobscured line-of-sight for this source. An alternative scenario in terms of a Compton-thick source is strongly disfavoured, requiring an exceptional geometrical configuration,…
We present the line observations in our ALMA imaging spectral scan toward three deeply buried nuclei in NGC 4418 and Arp 220. We cover 67 GHz in $f_{\rm rest}$=215-697 GHz at about 0.2$"$ (30, 80 pc) resolution. All the nuclei show dense line forests; we report our initial line identification using 55 species. The line velocities generally indicate gas rotation around each nucleus, tracing nuclear disks of $\sim$100 pc sizes. We confirmed the counter-rotation of the nuclear disks in Arp 220 and that of the nuclear disk and the galactic disk in NGC 4418. While the brightest lines exceed 100 K, …
We used the SPIRE/FTS instrument aboard the Herschel Space Observatory (HSO) to obtain the Spectral Line Energy Distributions (SLEDs) of CO from J=4-3 to J=13-12 of Arp 193 and NGC 6240, two classical merger/starbursts selected from our molecular line survey of local Luminous Infrared Galaxies (LIRGs: L_{IR}>=10^{11} L_{sol}). The high-J CO SLEDs are then combined with ground-based low-J CO, {13}CO, HCN, HCO+, CS line data and used to probe the thermal and dynamical states of their large molecular gas reservoirs. We find the two CO SLEDs strongly diverging from J=4-3 onwards, with NGC6240 havi…
We present results from our Giant Metrewave Radio Telescope (GMRT) HI observations of the interacting pair Arp 202 (NGC 2719 and NGC 2719A). Earlier deep UV(GALEX) observations of this system revealed a tidal tail like extension with a diffuse object towards its end, proposed as a tidal dwarf galaxy (TDG) candidate. We detect HI emission from the Arp 202 system, including HI counterparts for the tidal tail and the TDG candidate. Our GMRT HI morphological and kinematic results clearly link the HI tidal tail and the HI TDG counterparts to the interaction between NGC 2719 and NGC 2719A, thus stre…
We present a Cepheid-based distance to the nearby Seyfert galaxy NGC\,6814 from {\it Hubble Space Telescope} observations. We obtained F555W and F814W imaging over the course of 12 visits with logarithmic time spacing in 2013 August$-$October. We detected and made photometric measurements for 16,469 unique sources across all images in both filters, from which we identify 90 excellent Cepheid candidates spanning a range of periods of $13-84$ days. We find evidence for incompleteness in the detection of candidates at periods <21 days. Based on the analysis of Cepheid candidates above the incompl…
We present the variability analysis of a 100 ks XMM-Newton observation of the Seyfert 1.5 active galaxy NGC 3227. The observation found NGC 3227 in a period where its hard power-law component displayed remarkably little long-term variability. This lucky event allows us to observe clearly a soft spectral component undergoing a large-amplitude but slow flux variation. Using combined spectral and timing analysis we isolate two independent variable continuum components and characterize their behavior as a function of timescale. Rapid and coherent variations throughout the 0.2-10 keV band reveal a …
We observed with ALMA three deeply buried nuclei in two galaxies, NGC 4418 and Arp 220, at $\sim$0.2$''$ resolution over a total bandwidth of 67 GHz in $f_{\rm rest}$ = 215 - 697 GHz. Here we (1) introduce our program, (2) describe our data reduction method for wide-band, high-resolution imaging spectroscopy, (3) analyze in visibilities the compact nuclei with line forests, (4) develop a continuum-based estimation method of dust opacity and gas column density in heavily obscured nuclei, which uses the BGN (buried galactic nuclei) model and is sensitive to $\log(N_{\rm H_2}/{\rm cm}^{-2}) \sim …
Spectral data cubes of the interacting pair of galaxies NGC 2535 and NGC 2536 (the Arp 82 system) targeting bright emission lines in the visible band, obtained with the imaging Fourier transform spectrometer (iFTS) SITELLE attached to the Canada-France-Hawaii Telescope (CFHT), are presented. Analysis of H$\upalpha$ velocity maps reveals a bar in $\rm NGC\,2536$. In $\rm NGC\,2535$, we find strong non-circular motions outside the ocular ring, in the elliptical arc and tidal tails of $\rm NGC\,2535$ and a misalignment between the kinematic and photometric position angles. We detect 155 HII regio…
Nearby merging pairs are unique laboratories in which one can study the gravitational effects on the individual interacting components. In this manuscript, we report the characterization of selected HII regions along the peculiar galaxy NGC 2936, member of the galaxy pair Arp 142, an E+S interaction, known as "The Penguin". Using Gemini South spectroscopy we have derived a high enhancement of the global star formation rate SFR=35.9 Msun/yr probably stimulated by the interaction. Star-forming regions on this galaxy display oxygen abundances that are consistent with solar metallicities. The curr…
We report the complex radio properties of the radio galaxy NGC 2329 that resides in the centre of the galaxy cluster Abell 569. For this study, we have used archival data from the Very Large Array (VLA) at various resolutions and frequencies, as well as the Very Long Baseline Array (VLBA). While the wide-angle tailed (WAT) Fanaroff-Riley type I (FR I) radio morphology of the source has been discussed widely in the literature, the nature of the inner lobes has not been as widely discussed. In particular, we note that the inner lobes resemble the bubble-like radio structures observed in Seyfert …
The origin of narrow line region (NLR) outflows remains unknown. In this paper, we explore the scenario in which these outflows are circumnuclear clouds driven by energetic accretion disk winds. We choose the well-studied nearby Seyfert galaxy NGC 4151 as an example. By performing 3D hydrodynamical simulations, we are able to reproduce the radial distributions of velocity, mass outflow rate and kinetic luminosity of NLR outflows in the inner 100 pc deduced from spatial resolved spectroscopic observations. The demanded kinetic luminosity of disk winds is about two orders of magnitude higher tha…
Context. The putative tori surrounding the accretion disks of active galactic nuclei (AGNs) play a fundamental role in the unification scheme of AGNs. Infrared long-baseline interferometry allows us to study the inner dust distribution in AGNs with unprecedented spatial resolution over a wide infrared wavelength range. Aims. Near- and mid-infrared interferometry is used to investigate the milli-arcsecond-scale dust distribution in the type 1.5 Seyfert nucleus of NGC 3783. Methods. We observed NGC 3783 with the VLTI/AMBER instrument in the K-band and compared our observations with models. Resul…
A strong effort has been devoted to understand the physical origin of radio emission from low-luminosity AGN (LLAGN), but a comprehensive picture is still missing. We used high-resolution ($\le$1 arcsec), multi-frequency (1.5, 5.5, 9 and 14 GHz) NSF's Karl G. Jansky Very Large Array (VLA) observations to characterise the state of the nuclear region of ten Seyfert nuclei, which are the faintest members of a complete, distance-limited sample of 28 sources. With the sensitivity and resolution guaranteed by the VLA-A configuration, we measured radio emission for six sources (NGC3185, NGC3941, NGC4…
We report the discovery of a secondary pair of radio lobes in the Seyfert galaxy NGC 2639 with polarization-sensitive observations with the Karl G. Jansky Very Large Array (VLA). The presence of these lobes, which are aligned nearly perpendicular to the known set of radio lobes observed in the east-west direction, has not been reported previously in the literature. The in-band rotation measure image shows gradients in both the lobes indicative of organised magnetic field structures on kpc-scales. The magnetic field structure is aligned with the jet/lobe direction in both the lobes. Based on th…
We derive a distance of $15.8\pm0.4$ Mpc to the archetypical Seyfert 1 galaxy NGC 4151 based on the near-infrared Cepheid Period-Luminosity relation and new Hubble Space Telescope multiband imaging. This distance determination, based on measurements of 35 long-period ($P > 25$d) Cepheids, will support the absolute calibration of the supermassive black hole mass in this system, as well as studies of the dynamics of the feedback or feeding of its active galactic nucleus.
We report B, V, and R band CCD photometry of the Seyfert galaxy NGC 4151 obtained with the 1.0-m telescope at Weihai Observatory of Shandong University and the 1.56-m telescope at Shanghai Astronomical Observatory from 2005 December to 2013 February. Combining all available data from literature, we have constructed a historical light curve from 1910 to 2013 to study the periodicity of the source using three different methods (the Jurkevich method, the Lomb-Scargle periodogram method and the Discrete Correlation Function method). We find possible periods of P_1=4\pm0.1, P_2=7.5\pm0.3 and P_3=15…
The discovery of two active black holes in the Seyfert galaxy NGC 3393, separated by about 490 light years, revealed a merging event. This led us to look for other evidences of galaxy collision and merging through the analysis of the observed spectra in different frequency ranges. We found preshock densities higher by a factor of about 10 in the NGC 3393 NLR than in other AGN and patches of ionized matter beyond the observed NLR bulk. They can be explained by compression and heating of the gas downstream of shock waves created by collision. Metallicity in terms of the O/H relative abundance, i…
We report the hard X-ray (3-50 keV) view of the compact group HCG 16 (Arp 318) observed with Nuclear Spectroscopic Telescope Array (NuSTAR). NGC 838 and NGC 839 are undetected at energies above 8 keV, showing no evidence of heavily obscured active galactic nuclei (AGNs). This confirms that these are starburst-dominant galaxies as previously suggested. We perform a comprehensive broadband (0.3-50 keV) X-ray spectral analysis of the interacting galaxies NGC 833 and NGC 835, using data of NuSTAR, Chandra, and XMM-Newton observed on multiple epochs from 2000 to 2015. NuSTAR detects the transmitted…
(Abridged) Based on UV to X-ray and radio to UV flux ratios, some argue that low ionization emission line regions (LINERs) and low luminosity AGN (LLAGN) are a scaled-down version of their more luminous predecessors Seyfert galaxies. Others, based on the lack of X-ray short (hours) time-scale variability, the non-detection of an iron line at 6.4 keV, and the faint UV emission, suggest the truncation of the classical thin accretion disk in the inner regions of the AGN where a radiatively inefficient accretion flow (RIAF) structure forms. We investigate the LINER-Seyfert connection by studying t…
We present the results of a reverberation-mapping program targeting NGC5273, a nearby early-type galaxy with a broad-lined active galactic nucleus. Over the course of the monitoring program, NGC5273 showed strong variability that allowed us to measure time delays in the responses of the broad optical recombination lines to changes in the continuum flux. A weighted average of these measurements results in a black hole mass determination of $M_{\rm BH} = (4.7 \pm 1.6) \times 10^6$ M$_{\odot}$. An estimate of the size of the black hole sphere of influence in NGC5273 puts it just at the limit of t…
We derive a distance of $D = 16.6 \pm 0.3$~Mpc ($μ=31.10\pm0.04$~mag) to the archetypal narrow-line Seyfert 1 galaxy NGC 4051 based on Cepheid Period--Luminosity relations and new Hubble Space Telescope multiband imaging. We identify 419 Cepheid candidates and estimate the distance at both optical and near-infrared wavelengths using subsamples of precisely-photometered variables (123 and 47 in the optical and near-infrared subsamples, respectively). We compare our independent photometric procedures and distance-estimation methods to those used by the SH0ES team and find agreement to 0.01~mag. …
We present Atacama Large Millimeter/submillimeter Array observations at $\approx100$ GHz with $0.05$ arcsec (3 pc) resolution of the kiloparsec-scale jet seen in the nearby Seyfert galaxy NGC 1068, and we report the presence of parsec-scale blobs at the head of the jet. The combination of the detected radio flux ($\approx0.8$ mJy), spectral index ($\approx0.5$), and the blob size ($\approx10$ pc) suggests a strong magnetic field of $B\approx240\,μ$G. Such a strong magnetic field most likely implies magnetic field amplification by streaming cosmic rays. The estimated cosmic-ray power by the jet…
We present an analysis of the metallicity and star formation activities of HII regions in the interacting system Arp 86, based on the first scientific observation of the multi-object spectroscopy on the 2.16m Telescope at Xinglong Observatory. We find that the oxygen abundance gradient in Arp 86 is flatter than that in normal disk galaxies, which confirms that gas inflows caused by tidal forces during encounters can flatten the metallicity distributions in galaxies. The companion galaxy NGC 7752 is currently experiencing a galaxy-wide starburst with higher surface density of star formation rat…
We have mapped the extended narrow line region (ENLR) of NGC 3393 on scales of $r\lesssim4^{\prime\prime}$ ($\sim1\,$kpc) from the nucleus using emission line images of H$α\,\lambda6563$, [O III]$\lambda5007$, and [S II]$λ\lambda6717,6731$ taken with HST as part of the CHandra survey of Extended Emission line Regions in nearby Seyfert galaxies (CHEERS). By mapping these lines onto a spatially resolved Baldwin-Phillips-Terlevich (BPT) diagram, we investigate the impact of feedback from a Compton-thick AGN on its circumnuclear ISM. We find the expected Seyfert-like emission within the ionization…
We present optical photometric observations of SN 2018aoq from 2 to 100 days after explosion, and 7 spectra at epochs from 11 to 71 days. The light curves and spectra are typical for SNe II-P. As previously reported, SN 2018aoq appears to be of intermediate brightness between subluminous and normal SNe II-P. SN 2018aoq was discovered in Seyfert galaxy NGC 4151, for which the distance is uncertain. We utilised the Expanding Photosphere Method using three sets of filter combinations and velocities derived from the absorption minima of FeII lines and obtained a distance of 20.0 +-1.6 Mpc. The Sta…
