116 research outputs found

    The first detection of near-infrared CN bands in active galactic nuclei: signature of star formation

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    We present the first detection of the near-infrared CN absorption band in the nuclear spectra of active galactic nuclei (AGN). This feature is a recent star formation tracer, being particularly strong in carbon stars. The equivalent width of the CN line correlates with that of the CO at 2.3 microns, as expected in stellar populations (SP) with ages between ~ 0.2 and ~ 2 Gyr. The presence of the 1.1 microns CN band in the spectra of the sources is taken as an unambiguous evidence of the presence of young/intermediate SP close to the central source of the AGN. Near-infrared bands can be powerful age indicators for star formation connected to AGN, the understanding of which is crucial in the context of galaxy formation and AGN feedback.Comment: Accepted for publication in The Astrophysical Journal Letters. 4 pages, 3 figure

    Multicolor photometry of ten Seyfert 1 galaxies

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    We present BVI photometry of ten Seyfert 1 galaxies and narrow band H-alpha images for six of these objects as well. The results indicate that the luminosity sample distribution has an amplitude of almost 4 magnitudes with an average of M_B=-20.7. The observed morphologies are confined to early type galaxies. A barred structure is found in only 2 objects. Despite that early morphological types are dominant in this sample, integrated (B-V) colors are very blue. For instance, the SO galaxies show, on average, a (B-V)=0.78. This effect seems to be caused by the luminosity contribution of the active nucleus and/or the disk to the total luminosity of the galaxy. In the B band, the contribution of the active galactic nucleus to the total luminosity of the galaxy varies from 3% to almost 60% and the bulge to disk luminosity ratio (L_bulge/L_disk) ranges from 0.6 to 22. Signs of tidal interactions seems to be a common characteristic since they are observed in 6 of the objects and one of them seems to be located in a poor cluster not yet identified in the literature. H_alpha extended emission is rare, with only 1 galaxy showing clear evidence of it. Luminosity profile decomposition shows that the model Gauss + bulge + disk properly reproduces the surface brightness of the galaxies. However, in order to account for the luminosity profile, most of the disk galaxies needs the inner truncated exponential form with a central cutoff radius ranging from 3 to 10 kpc. This is interpreted in terms of reddened regions that are well identified in the B-V color maps. These regions present very similar colors among them, with (B-V)~1.2. This fact could be associated to the presence of dust confined in the inner regions of the galaxies.Comment: 14 pages, 25 figures. Accepted to Astronomy & Astrophysic

    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 μm where low ionization (Paα and Brδ), high ionization ([S XI]λ1.920 μm and [Si VI]λ1.963 μm), 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, Brδ, 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 Ṁout,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

    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 μm where low ionization (Paα and Brδ), high ionization ([S XI]λ1.920 μm and [Si VI]λ1.963 μm), 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, Brδ, 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 Ṁout,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

    Extended X-ray emission in PKS 1718-649

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    © ESO 2018. PKS 1718-649 is one of the closest and most comprehensively studied candidates of a young active galactic nucleus (AGN) that is still embedded in its optical host galaxy. The compact radio structure, with a maximal extent of a few parsecs, makes it a member of the group of compact symmetric objects (CSO). Its environment imposes a turnover of the radio synchrotron spectrum towards lower frequencies, also classifying PKS 1718-649 as gigahertz-peaked radio spectrum (GPS) source. Its close proximity has allowed the first detection of extended X-ray emission in a GPS/CSO source with Chandra that is for the most part unrelated to nuclear feedback. However, not much is known about the nature of this emission. By co-adding all archival Chandra data and complementing these datasets with the large effective area of XMM-Newton, we are able to study the detailed physics of the environment of PKS 1718-649. Not only can we confirm that the bulk of the kiloparsec-scale environment emits in the soft X-rays, but we also identify the emitting gas to form a hot, collisionally ionized medium. While the feedback of the central AGN still seems to be constrained to the inner few parsecs, we argue that supernovae are capable of producing the observed large-scale X-ray emission at a rate inferred from its estimated star formation rate

    Extended X-ray emission in PKS 1718−-649

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    PKS 1718−-649 is one of the closest and most comprehensively studied candidates of a young active galactic nucleus (AGN) that is still embedded in its optical host galaxy. The compact radio structure, with a maximal extent of a few parsecs, makes it a member of the group of compact symmetric objects (CSO). Its environment imposes a turnover of the radio synchrotron spectrum towards lower frequencies, also classifying PKS 1718−-649 as gigahertz-peaked radio spectrum (GPS) source. Its close proximity has allowed the first detection of extended X-ray emission in a GPS/CSO source with Chandra that is for the most part unrelated to nuclear feedback. However, not much is known about the nature of this emission. By co-adding all archival Chandra data and complementing these datasets with the large effective area of XMM-Newton, we are able to study the detailed physics of the environment of PKS 1718−-649. Not only can we confirm that the bulk of the ≲\lesssimkiloparsec-scale environment emits in the soft X-rays, but we also identify the emitting gas to form a hot, collisionally ionized medium. While the feedback of the central AGN still seems to be constrained to the inner few parsecs, we argue that supernovae are capable of producing the observed large-scale X-ray emission at a rate inferred from its estimated star formation rate.Comment: 5 pages, 2 figures, 2 tables, accepted for publication by A&

    Is IRAS 01072+4954 a True-Seyfert 2? Hints from Near Infrared Integral Field Spectroscopy

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    In contrast to the predictions of the unified model, some X-ray unobscured Seyfert 2 galaxies have been discovered in the last decade. One of them, the starburst/Seyfert composite galaxy IRAS 01072+4954 (z=0.0236), has a typical Type~1 X-ray emission, while its optical spectrum resembles an HII galaxy and lacks the expected broad lines. We performed near-infrared integral-field observations of this object with the aim to determine the nature of its nuclear emission and to find indications for the existence or absence of a broad-line region. Several reasons have been proposed to explain such peculiar emission. We studied the validity of such hypotheses, including the possibility for it to be True-Seyfert~2. We found little obscuration towards the nucleus A_V = 2.5 mag, and a nuclear star-formation rate Sigma_SFR < 11.6 Msun yr^{-1} kpc^{-2}, which is below the average in Seyferts. Unresolved hot-dust emission with T ~ 1150 K seems to indicate the presence of a torus with its axis close to the line of sight. We found that IRAS 01072+4954 hosts a low mass black hole with an estimated mass of M_BH ~ 10^5 Msun and an upper limit of 2.5x10^6 Msun. Its bolometric luminosity is L_bol ~ 2.5x10^{42} erg/s, which yields a high accretion rate with an Eddington ratio ~ 0.2. If the relations found in more massive systems also apply to this case, then IRAS 01072+4954 should show broad emission lines with FWHM_{broad} ~(400-600) km/s. Indeed, some indications for such narrow broad-line components are seen in our data, but the evidence is not yet conclusive. This source thus seems not to be a True-Seyfert 2, but an extreme case of a narrow line Seyfert 1, which, due to the faintness of the active nucleus, does not have strong FeII emission in the optical.Comment: 16 pages, 11 figures. A&A Accepted versio

    Mrk 609: resolving the circum-nuclear structure with near-infrared integral field spectroscopy

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    We present first results of near infrared J and H+K ESO-SINFONI integral field spectroscopy of the composite starburst/Seyfert 1.8 galaxy Mrk 609. The data were taken during the science verification period of SINFONI. We aim to investigate the morphology and excitation conditions within the central 2 kpc. Additional Nobeyama 45 m CO(1-0) data are presented, which we used to estimate the molecular gas mass. The source was selected from a sample of adaptive optics suitable, SDSS/ROSAT based, X-ray bright AGN with redshifts of 0.03 < z < 1. This sample allows for a detailed study of the NIR properties of the nuclear and host environments with high spectral and spatial resolution. Our NIR data reveal a complex emission-line morphology, possibly associated with a nuclear bar seen in the reconstructed continuum images. The detections of [SiVI] and a broad Pa alpha component are clear indicators for the presence of an accreting super-massive black hole at the center of Mrk 609. In agreement with previous observations we find that the circum-nuclear emission is not significantly extincted. The analysis of the high angular resolution rotational-vibrational molecular hydrogen and forbidden [FeII] emission reveals a LINER character of the nucleus. The large H_2 gas mass deduced from the CO(1-0) observation provides the fuel needed to feed the starburst and Seyfert activity in Mrk 609. High angular resolution imaging spectroscopy provides an ideal tool to resolve the nuclear and starburst contribution in active galaxies. We show that Mrk 609 exhibits LINER features, that appear to be hidden in larger aperture visible/NIR spectra.Comment: published by A&A, 19 pages, 16 figures, version with high resolution figures is available via http://www.ph1.uni-koeln.de/~zuther/mrk609.pd

    Experiential Learning and Mentorship in Global Health Leadership Programs: Capturing Lessons from Across the Globe.

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    OBJECTIVES: The changing global landscape of disease and public health crises, such as the current COVID-19 pandemic, call for a new generation of global health leaders. As global health leadership programs evolve, many have incorporated experiential learning and mentoring (ELM) components into their structure. However, there has been incomplete consideration on how ELM activities are deployed, what challenges they face and how programs adapt to meet those challenges. This paper builds on the co-authors' experiences as trainees, trainers, organizers and evaluators of six global health leadership programs to reflect on lessons learned regarding ELM. We also consider ethics, technology, gender, age and framing that influence how ELM activities are developed and implemented. FINDINGS: Despite the diverse origins and funding of these programs, all six are focused on training participants from low- and middle-income countries drawing on a diversity of professions. Each program uses mixed didactic approaches, practice-based placements, competency and skills-driven curricula, and mentorship via various modalities. Main metrics for success include development of trainee networks, acquisition of skills and formation of relationships; programs that included research training had specific research metrics as well. Common challenges the programs face include ensuring clarity of expectations of all participants and mentors; maintaining connection among trainees; meeting the needs of trainee cohorts with different skill sets and starting points; and ensuring trainee cohorts capture age, gender and other forms of diversity. CONCLUSIONS: ELM activities for global health leadership are proving even more critical now as the importance of effective individual leaders in responding to crises becomes evident. Future efforts for ELM in global health leadership should emphasize local adaptation and sustainability. Practice-based learning and established mentoring relationships provide the building blocks for competent leaders to navigate complex dynamics with the flexibility and conscientiousness needed to improve the health of global populations. Key Takeaways: Experiential learning and mentorship activities within global health leadership programs provide the hands-on practice and support that the next generation of global health leaders need to address the health challenges of our times.Six global health leadership programs with experiential learning and mentorship components are showcased to highlight differences and similarities in their approaches and capture a broad picture of achievements that can help inform future programs.Emphasis on inter-professional training, mixed-learning approaches and mentorship modalities were common across programs. Both individual capacity building and development of trainees' professional networks were seen as critical, reflecting the value of inter-personal connections for long-term leadership success.During program design, future programs should recognize the "frame" within which the program will be incorporated and intentionally address diversity-in all its forms-during recruitment as well as consider North-South ethics, leadership roles, hierarchies and transition plans

    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 μm where low ionization (Paα and Brδ), high ionization ([S XI]λ1.920 μm and [Si VI]λ1.963 μm), 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, Brδ, 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 Ṁout,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
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