49 research outputs found

    3D kinematics of the near-IR HH 223 outflow in L723

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    In this work, we derive the full 3D kinematics of the near-infrared outflow HH 223, located in the dark cloud Lynds 723 (L723), where a well-defined quadrupolar CO outflow is found. HH 223 appears projected on to the two lobes of the eastwest CO outflow. The radio continuum source VLA 2, towards the centre of the CO outflow, harbours a multiple system of low-mass young stellar objects. One of the components has been proposed to be the exciting source of the eastwest CO outflow. From the analysis of the kinematics, we get further evidence on the relationship between the near-infrared and CO outflows and on the location of their exciting source. The proper motions were derived using multi-epoch, narrow-band H2 (2.122 ÎŒm line) images. Radial velocities were derived from the 2.122 ÎŒm line of the spectra. Because of the extended (∌5 arcmin), S-shaped morphology of the target, the spectra were obtained with the multi-object-spectroscopy (MOS) observing mode using the instrument Long-Slit Intermediate Resolution Infrared Spectrograph (LIRIS) at the 4.2 m William Herschel Telescope. To our knowledge, this work is the first time that MOS observing mode has been successfully used in the near-infrared range for an extended target

    The infrared to X-ray correlation spectra of unobscured type 1 active galactic nuclei

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    We use new X-ray data obtained with the Nuclear Spectroscopic Telescope Array (NuSTAR), near-infrared (NIR) fluxes and mid-infrared (MIR) spectra of a sample of 24 unobscured type 1 active galactic nuclei (AGN) to study the correlation between various hard X-ray bands between 3 and 80 keV and the infrared (IR) emission. The IR to X-ray correlation spectrum (IRXCS) shows a maximum at ∌15–20 ÎŒm, coincident with the peak of the AGN contribution to the MIR spectra of the majority of the sample. There is also an NIR correlation peak at ∌2 ÎŒm, which we associate with the NIR bump observed in some type 1 AGN at ∌1–5 ÎŒm and is likely produced by nuclear hot dust emission. The IRXCS shows practically the same behaviour in all the X-ray bands considered, indicating a common origin for all of them. We finally evaluated correlations between the X-ray luminosities and various MIR emission lines. All the lines show a good correlation with the hard X-rays (ρ ≄ 0.7), but we do not find the expected correlation between their ionization potentials and the strength of the IRXCS

    Nearby normal and luminous infrared galaxies with the SKA

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    The SKA will routinely provide ”Jy sensitivity and sub-arcsecond angular resolutions at radio wavelengths. Planned SKA surveys will image vast numbers of nearby galaxies, which are expected to provide a cornerstone in our understanding of star-formation and accretion activity in the local Universe. Here, we outline some of the key continuum and molecular line studies of local galaxies, where the SKA will have a significant scientific impact and where the Spanish astrophysical community is particularly active.MAPT, AA, and RHI acknowledge support from the Spanish Ministerio de Economía y Competitividad (MINECO) through grant AYA2012-38491-C02-02. S.G.B. acknowledges support from the Spanish MINECO through grants AYA2010-15169, AYA2012-32295, and program CONSOLIDER INGENIO 2010, under grant Molecular Astrophysics: The Herschel and ALMA EraASTROMOL (ref CSD2009-00038). S.G.B also acknowledges support from the Junta de Andalucia through TIC-114 and the Excellence Project P08-TIC-03531. A.A.H. and LC acknowledge support from the Spanish MINECO through grants AYA-2012-31447 and AYA-2012-32295. JHK acknowledges financial support to the DAGAL network from the People Programme (Marie Curie Actions) of the European Unions Seventh Framework Programme FP7/2007-2013/ under REA grant agreement number PITNGA-2011-289313, and from the Spanish MINECO under grant number AYA2013-41243-P.Peer Reviewe

    Upholding the unified model for Active Galactic Nuclei: VLT/FORS2 spectropolarimetry of Seyfert 2 galaxies

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    The origin of the unification model for Active Galactic Nuclei (AGN) was the detection of broad hydrogen recombination lines in the optical polarized spectrum of the Seyfert 2 galaxy (Sy2) NGC 1068. Since then, a search for the hidden broad-line region (HBLR) of nearby Sy2s started, but polarized broad lines have only been detected in ?30–40% of the nearby Sy2s observed to date. Here we present new VLT/FORS2 optical spectropolarimetry of a sample of 15 Sy2s, including Compton-thin and Compton-thick sources. The sample includes six galaxies without previously published spectropolarimetry, some of them normally treated as non-hidden BLR (NHBLR) objects in the literature, four classified as NHBLR, and five as HBLR based on previous data. We report ?4? detections of a HBLR in 11 of these galaxies (73% of the sample) and a tentative detection in NGC 5793, which is Compton-thick according to the analysis of X-ray data performed here. Our results confirm that at least some NHBLRs are misclassified, bringing previous publications reporting differences between HBLR and NHBLR objects into question. We detect broad H? and H? components in polarized light for 10 targets, and just broad H? for NGC 5793 and NGC 6300, with line widths ranging between 2100 and 9600 km s?1. High bolometric luminosities and low column densities are associated with higher polarization degrees, but not necessarily with the detection of the scattered broad components

    Investigating the impact of quasar-driven outflows on galaxies at z ∌ 0.3–0.4

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    Aims. We present a detailed study of the kinematics of 19 type 2 quasars (QSO2s) with redshifts in the range 0.3  108.5 L⊙. We aim to advance our understanding of the active galactic nucleus (AGN) feedback phenomenon by correlating outflow properties with (i) young stellar populations (YSPs) with ages < 100 Myr, (ii) the optical morphology and the environment of the galaxies, and (iii) the radio luminosity. Methods. We characterized the ionized gas kinematics using the [OIII]λ5007 Å emission line profiles detected in intermediate spectral resolution (R ∌ 1500–2500) optical spectra of the QSO2s. To do this, we employed three different outflow detection methods: multicomponent parametric, flux-weighted nonparametric, and peak-weighted nonparametric. Results. We detect ionized outflows in 18 of the 19 QSO2s using the parametric analysis, and in all of them using the nonparametric methods. We find higher outflow masses using the parametric analysis (average log MOF(M⊙) = 6.47  ±  0.50), and higher mass rates and kinetic powers with the flux-weighted nonparametric method (MOF = 4.0  ±  4.4 M⊙ yr−1 and Ekin = 41.9  ±  0.6 erg s−1). However, when we use the parametric method and the maximum outflow velocities (vmax), we measure the highest outflow mass rates and kinetic energies (MOF = 23  ±  35 M⊙ yr−1 and log(Ekin) = 42.9  ±  0.6 erg s−1). We do not find any significant correlation between the outflow properties and the previously mentioned AGN and galaxy-wide properties. Conclusions. Four of the five QSO2s without a YSP of age < 100 Myr show highly disturbed kinematics, whereas only 5 out of the 14 QSO2s with YSPs show similarly asymmetric [OIII] profiles. Despite the small sample size, this might be indicative of negative feedback. The lack of a correlation between the outflow properties and the galaxies optical morphologies might be due to their different dynamical timescales (millions of years in the case of the outflows versus billions of years in the case of galaxy mergers). Last, the small radio luminosity range covered by our sample, log(L5 GHz) = [22.1, 24.7] W Hz−1, may impede the detection of any correlation between radio emission and outflow properties

    Clues from Spitzer/IRS spectra on the Compton thickness and the existence of the dusty torus

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    [Context]: Most of the optically classified low-ionisation, narrow emission-line regions (LINERs) nuclei host an active galactic nucleus (AGN). However, how they fit into the unified model (UM) of AGN is still an open question. [Aims]: The aims of this work are to study at mid-infrared (mid-IR) (1) the Compton-thick nature of LINERs (i.e. hydrogen column densities of NH> 1.5 × 1024 cm-2) and (2) the disappearance of the dusty torus in LINERs predicted from theoretical arguments. [Methods]: We have compiled all the available low spectral-resolution, mid-IR spectra of LINERs from the InfraRed Spectrograph (IRS) onboard Spitzer. The sample contains 40 LINERs. We have complemented the LINER sample with Spitzer/IRS spectra of PGQSOs, Type-1 Seyferts (S1s), Type-2 Seyferts (S2s), and StarBurst (SB) nuclei. We studied the AGN compared to the starburst content in our sample using different indicators: the equivalent width of the polycyclic aromatic hydrocarbon at 6.2 ÎŒm, the strength of the silicate feature at 9.7 ÎŒm, and the steepness of the mid-IR spectra. We classified the spectra as SB-dominated and AGN-dominated, according to these diagnostics and compared the average mid-IR spectra of the various classes. Moreover, we studied the correlation between the 12 ÎŒm luminosity, ÎœLÎœ(12 ÎŒm), and the 2−10 keV energy band X-ray luminosity, LX(2−10 keV). [Results]: In 25 out of the 40 LINERs (i.e. 62.5%), the mid-IR spectra are not SB-dominated, similar to the comparison S2 sample (67.7%). The average spectra of both SB-dominated LINERs and S2s are very similar to the average spectrum of the SB class. The average spectrum of AGN-dominated LINERs is different from the average spectra of the other optical classes, showing a rather flat spectrum at 6-28 ÎŒm. We find that the average spectrum of AGN-dominated LINERs with X-ray luminosities LX(2−10 keV) > 1041 erg/s is similar to the average mid-IR spectrum of AGN-dominated S2s. However, faint LINERs (i.e. LX(2−10 keV) < 1041 erg/s) show flat spectra different from any of the other optical classes. The correlation between ÎœLÎœ(12 ÎŒm) and LX(2−10 keV) for AGN nicely extends towards low luminosities only if SB-dominated LINERs are excluded and if the 2−10 keV band X-ray luminosity is corrected in Compton-thick LINER candidates. [Conclusions]: We find that LINERs proposed as Compton-thick candidates at X-ray wavelengths may be confirmed according to the X-ray to mid-IR luminosity relation. We show evidence that the dusty-torus disappear when their bolometric luminosity is below Lbol ≃ 1042 erg/s. We suggest that the dominant emission at mid-IR of faint LINERs might be a combination of an elliptical galaxy host (characterised by the lack of gas), a starburst, a jet, and/or ADAF emission. Alternatively, the mid-IR emission of some of these faint LINERs could be a combination of elliptical galaxy plus carbon-rich planetary nebulae. To reconcile the Compton-thick nature of a large number of LINERs without dusty-torus signatures, we suggest that the material producing the Compton-thick X-ray obscuration is free of dust.This research has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under the grant (project refs. AYA2013-42227-P, AYA 2012-39168-C03-01, and AYA 2010-15169) and by La Junta de Andalucia (TIC 114). AAH acknowledges support from grant AYA2012-31447. D.D. acknowledges support from grant 107313 from PAPIIT, UNAM. C.R.A. is supported by a Marie Curie Intra European Fellowship within the 7th European Community Framework Programme (PIEF-GA-2012-327934).Peer Reviewe

    Warm molecular and ionized gas kinematics in the type-2 quasar J0945+1737

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    We analyse Near-Infrared Integral Field Spectrograph (NIFS) observations of the type-2 quasar (QSO2) SDSS J094521.33+173753.2 to investigate its warm molecular and ionized gas kinematics. This QSO2 has a bolometric luminosity of 1045.7 erg s−1 and a redshift of z = 0.128. The K-band spectra provided by NIFS cover a range of 1.99–2.40 ÎŒm where low ionization (Paα and BrÎŽ), high ionization ([S XI]λ1.920 ÎŒm and [Si VI]λ1.963 ÎŒm), and warm molecular lines (from H21-0S(5) to 1-0S(1)) are detected, allowing us to study the multi-phase gas kinematics. Our analysis reveals gas in ordinary rotation in all the emission lines detected and also outflowing gas in the case of the low and high ionization emission lines. In the case of the nuclear spectrum, which corresponds to a circular aperture of 0.3″ (686 pc) in diameter, the warm molecular lines can be characterized using a single Gaussian component of full width at half maximum (FWHM) = 350 − 400 km s−1, while Paα, BrÎŽ, and [Si VI] are best fitted with two blue-shifted Gaussian components of FWHM ∌ 800 and 1700 km s−1, in addition to a narrow component of ∌300 km s−1. We interpret the blue-shifted broad components as outflowing gas, which reaches the highest velocities, of up to −840 km s−1, in the south-east direction (PA ∌ 125°), extending up to a distance of ∌3.4 kpc from the nucleus. The ionized outflow has a maximum mass outflow rate of áč€out,max = 42–51 M⊙ yr−1, and its kinetic power represents 0.1% of the quasar bolometric luminosity. Very Large Array (VLA) data of J0945 show extended radio emission (PA ∌ 100°) that is aligned with the clumpy emission traced by the narrow component of the ionized lines up to scales of several kiloparsecs, and with the innermost part of the outflow (central ∌0.4″ = 915 pc). Beyond that radius, at the edge of the radio jet, the high velocity gas shows a different PA of ∌125°. This might be an indication that the line-emitting gas is being compressed and accelerated by the shocks generated by the radio jet

    The nuclear and extended infrared emission of the Seyfert galaxy NGC 2992 and the interacting system Arp 245

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    We present subarcsecond resolution infrared (IR) imaging and mid-IR (MIR) 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 polycyclic aromatic hydrocarbon features detected in the GTC/CanariCam 7.5–13 ÎŒm 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 ÎŒm, where the active galactic nuclei (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 ÎŒm spectrum (∌630 pc) in AGN and starburst components, using different starburst templates. We find that, whereas at shorter MIR wavelengths the starburst component dominates (64 per cent at 6 ÎŒm), the AGN component reaches 90 per cent at 20 ÎŒm. 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.IGB acknowledges financial support from the Instituto de AstrofĂ­sica de Canarias through Fundacion La Caixa. This research was partly supported by a Marie Curie Intra European Fellowship within the 7th European Community Framework Programme (PIEF-GA-2012-327934). CRA and IGB acknowledge financial support from the Spanish Ministry of Science and Innovation (MICINN) through project PN AYA2013-47742-C4-2-P. AAH acknowledges funding from the Spanish Ministry of Economy and Competitiveness under grant AYA2012-31447, which is party funded by the FEDER program. PE acknowledges support from the Spanish Plan Nacional de AstronomĂ­a y AstrofĂ­sica under grant AYA2012-31277. OGM acknowledges support from grant AYA2012-39168-C03-01. TDS was supported by ALMA-CONICYT grant number 31130005.Peer Reviewe

    The afterglow and kilonova of the short GRB 160821B

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    GRB 160821B is a short duration gamma-ray burst (GRB) detected and localized by the Neil Gehrels Swift Observatory in the outskirts of a spiral galaxy at z=0.1613, at a projected physical offset of 16 kpc from the galaxy's center. We present X-ray, optical/nIR and radio observations of its counterpart and model them with two distinct components of emission: a standard afterglow, arising from the interaction of the relativistic jet with the surrounding medium, and a kilonova, powered by the radioactive decay of the sub-relativistic ejecta. Broadband modeling of the afterglow data reveals a weak reverse shock propagating backward into the jet, and a likely jet-break at 3.5 d. This is consistent with a structured jet seen slightly off-axis while expanding into a low-density medium. Analysis of the kilonova properties suggests a rapid evolution toward red colors, similar to AT2017gfo, and a low nIR luminosity, possibly due to the presence of a long-lived neutron star. The global properties of the environment, the inferred low mass (M_ej < 0.006 Msun) and velocities (v > 0.05 c) of lanthanide-rich ejecta are consistent with a binary neutron star merger progenitor.Comment: 14 pages, 6 figures, MNRAS, in press. Moderate revision, added Figure 5 and X-ray data to Table

    Multiphase characterization of AGN winds in five local type-2 quasars

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    We present MEGARA integral field unit (IFU) observations of five local type-2 quasars (QSO2s, z ∌ 0.1) from the Quasar Feedback (QSOFEED) sample. These active galactic nuclei (AGN) have bolometric luminosities of 1045.5 − 46 erg s−1 and stellar masses of ∌1011 M⊙. The LR-V grating of MEGARA allows us to explore the kinematics of the ionized gas through the [O III]λ5007 Å emission line. The nuclear spectra of the five QSO2s, extracted in a circular aperture of ∌1.2″ (∌2.2 kpc) in diameter, matching the resolution of these seeing-limited observations, show signatures of high velocity winds in the form of broad (full width at half maximum, 1300 ≀ FWHM ≀ 2240 km s−1) and blueshifted components. We found that four out of the five QSO2s present outflows that we can resolve with our seeing-limited data, and they have radii ranging from 3.1 to 12.6 kpc. In the case of the two QSO2s with extended radio emission, we found that it is well aligned with the outflows, suggesting that low-power jets might be compressing and accelerating the ionized gas in these radio-quiet QSO2s. In the four QSO2s with spatially resolved outflows, we measured ionized mass outflow rates of 3.3–6.5 M⊙ yr−1 when we used [S II]-based densities, and of 0.7–1.6 M⊙ yr−1 when trans-auroral line-based densities were considered instead. We compared them with the corresponding molecular mass outflow rates (8–16 M⊙ yr−1), derived from CO(2–1) ALMA observations at 0.2″ resolution. The cold molecular outflows carry more mass than their ionized counterparts. However, both phases show lower outflow mass rates than those expected from observational scaling relations where uniform assumptions on the outflow properties were adopted. This might be indicating that the AGN luminosity is not the only driver of massive outflows and/or that these relations need to be rescaled using accurate outflow properties (i.e., electron density and radius). We did not find a significant impact of the outflows on the global star formation rates when considering the energy budget of the molecular and ionized outflows together. However, spatially resolved measurements of recent star formation in these targets are needed in order to evaluate this fairly, considering the dynamical timescales of the outflows, of 3–20 Myr for the ionized gas and 1–10 Myr for the molecular gas
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