scholarly journals Resolving the clumpy circumstellar environment of the B[e] supergiant LHA 120-S 35

2018 ◽  
Vol 612 ◽  
pp. A113 ◽  
Author(s):  
A. F. Torres ◽  
L. S. Cidale ◽  
M. Kraus ◽  
M. L. Arias ◽  
R. H. Barbá ◽  
...  
Keyword(s):  
Near Infrared ◽  
Complex Structure ◽  
Emission Lines ◽  
Spectral Variability ◽  
Visible Absorption ◽  
Stellar Cluster ◽  
Near Infrared Spectra ◽  
Ring Structures ◽  
Balmer Lines ◽  
Circumstellar Environment

Context. B[e] supergiants are massive post-main-sequence stars, surrounded by a complex circumstellar environment where molecules and dust can survive. The shape in which the material is distributed around these objects and its dynamics as well as the mechanisms that give rise to these structures are not well understood. Aims. The aim is to deepen our knowledge of the structure and kinematics of the circumstellar disc of the B[e] supergiant LHA 120-S 35. Methods. High-resolution optical spectra were obtained in three different years. Forbidden emission lines, that contribute to trace the disc at different distances from the star, are modelled in order to determine the kinematical properties of their line-forming regions, assuming Keplerian rotation. In addition, we used low-resolution near-infrared spectra to explore the variability of molecular emission. Results. LHA 120-S 35 displays an evident spectral variability in both optical and infrared regions. The P-Cygni line profiles of H I, as well as those of Fe II and O I, suggest the presence of a strong bipolar clumped wind. We distinguish density enhancements in the P-Cygni absorption component of the first Balmer lines, which show variations in both velocity and strength. The P-Cygni profile emission component is double-peaked, indicating the presence of a rotating circumstellar disc surrounding the star. We also observe line-profile variations in the permitted and forbidden features of Fe II and O I. In the infrared, we detect variations in the intensity of the H I emission lines as well as in the emission of the CO band-heads. Moreover, we find that the profiles of each [Ca II] and [O I] emission lines contain contributions from spatially different (complete or partial) rings. Globally, we find evidence of detached multi-ring structures, revealing density variations along the disc. We identify an inner ring, with sharp edge, where [Ca II] and [O I] lines share their forming region with the CO molecular bands. The outermost regions show a complex structure, outlined by fragmented clumps or partial-ring features of Ca II and O I. Additionally, we observe variations in the profiles of the only visible absorption features, the He I lines. Conclusions. We suggest that LHA 120-S 35 has passed through the red-supergiant (RSG) phase and evolves back bluewards in the Hertzsprung-Russell diagram. In this scenario, the formation of the complex circumstellar structure could be the result of the wind–wind interactions of the post-RSG wind with the previously ejected material from the RSG. The accumulation of material in the circumstellar environment could be attributed to enhanced mass-loss, probably triggered by stellar pulsations. However, the presence of a binary companion cannot be excluded. Finally, we find that LHA 120-S 35 is the third B[e] supergiant belonging to a young stellar cluster.

scholarly journals Unveiling the monster heart: unbeamed properties of blazar 4C 71.07

2020 ◽  
Vol 493 (2) ◽  
pp. 2793-2804
Author(s):  
C M Raiteri ◽  
J A Acosta Pulido ◽  
M Villata ◽  
M I Carnerero ◽  
P Romano ◽  
...  
Keyword(s):  
Near Infrared ◽  
High Redshift ◽  
Emission Lines ◽  
Line Broadening ◽  
Optical Telescope ◽  
Spectroscopic Monitoring ◽  
Near Infrared Spectra ◽  
Line Region ◽  
High Ionization ◽  
William Herschel

ABSTRACT 4C 71.07 is a high-redshift blazar whose optical radiation is dominated by quasar-like nuclear emission. We here present the results of a spectroscopic monitoring of the source to study its unbeamed properties. We obtained 24 optical spectra at the Nordic Optical Telescope and William Herschel Telescope and 3 near-infrared spectra at the Telescopio Nazionale Galileo. They show no evidence of narrow emission lines. The estimate of the systemic redshift from the Hβ and Hα broad emission lines leads to zsys = 2.2130 ± 0.0004. Notwithstanding the nearly face-on orientation of the accretion disc, the high-ionization emission lines present large broadening as well as noticeable blueshifts, which increase with the ionizing energy of the corresponding species. This is a clear indication of strong ionized outflows. Line broadening and blueshift appear correlated. We applied scaling relationships to estimate the mass of the supermassive black hole from the Balmer and C iv lines, taking into account the prescriptions to correct for outflow. They give $M_{\rm BH} \sim 2 \times 10^9 \, M_\odot$. We derived an Eddington luminosity $L_{\rm Edd} \sim 2.5 \times 10^{47} \rm \, erg \, s^{-1}$ ∼ Ldisc, and a broad-line region (BLR) luminosity of $L_{\rm BLR} \sim 1.5 \times 10^{46} \rm \, erg \, s^{-1}$. The line fluxes do not show significant variability in time. In particular, there is no line reaction to the jet flaring activity detected in 2015 October and November. This implies that the jet gives no contribution to the photoionization of the BLR in the considered period.

scholarly journals Evidence of AGN-driven Outflows in Young Radio Quasars Selected from the Wide-field Infrared Survey Explorer

2013 ◽  
Vol 9 (S304) ◽  
pp. 347-348
Author(s):  
Minjin Kim ◽  
Luis C. Ho ◽  
Carol J. Lonsdale ◽  
Mark Lacy ◽  
Andrew W. Blain ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Near Infrared ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Wide Field ◽  
Near Infrared Spectra ◽  
Sky Survey ◽  
Line Widths ◽  
Infrared Survey ◽  
Narrow Emission

AbstractWe present near-infrared spectra of young radio quasars selected by cross-correlating the Wide-field Infrared Survey Explorer (WISE) all-sky survey catalog with the radio catalog [Faint Images of the Radio Sky at Twenty cm (FIRST) and NRAO VLA Sky Survey (NVSS)]. The objects have typical redshifts of z ≈ 2 and [O III] luminosities of 107 erg s−1 comparable to those of luminous quasars. The observed flux ratios of narrow emission lines indicate that these objects appear to be powered by active galactic nuclei. The [O III] line is broad, with full width at half maximum ~1300 to 2100 km s−1, significantly larger than that of ordinary quasars. These large line widths might be explained by jet-induced outflows.

scholarly journals Emission Lines in the Near Infrared Spectra of Faint Planetary Nebulae

1978 ◽  
Vol 76 ◽  
pp. 123-124
Author(s):  
Yvette Andrillat ◽  
Léo Houziaux
Keyword(s):  
Spectral Range ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Planetary Nebulae ◽  
Emission Lines ◽  
Image Tube ◽  
Near Infrared Spectra

We obtained spectra of twelve faint planetary nebulae at the Cassegrain focus of the 193 cm telescope at Haute Provence Observatory (dispersion: 230 Åmm−1 spectral range 8000–11000 Å, receiver: ITT image tube with SI photocathode).

scholarly journals Emission Lines in the Near-infrared Spectra of the Infrared Quintuplet Stars in the Galactic Center

2017 ◽  
Vol 845 (2) ◽  
pp. 127 ◽  
Author(s):  
F. Najarro ◽  
T. R. Geballe ◽  
D. F. Figer ◽  
D. de la Fuente
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
Galactic Center ◽  
Emission Lines ◽  
Near Infrared Spectra

scholarly journals Gemini NIFS survey of feeding and feedback in nearby active galaxies – IV. Excitation

2021 ◽  
Vol 503 (4) ◽  
pp. 5161-5178
Author(s):  
Rogemar A Riffel ◽  
Marina Bianchin ◽  
Rogério Riffel ◽  
Thaisa Storchi-Bergmann ◽  
Astor J Schönell ◽  
...  
Keyword(s):  
Near Infrared ◽  
Galactic Nuclei ◽  
Seyfert Galaxies ◽  
Emission Lines ◽  
Coronal Emission ◽  
Near Infrared Spectra ◽  
Diagnostic Diagram ◽  
The Galaxy ◽  
Coronal Emission Line ◽  
Integral Field

ABSTRACT The near-infrared spectra of active galactic nuclei (AGN) present emission lines of different atomic and molecular species. The mechanisms involved in the origin of these emission lines in AGN are still not fully understood. We use J- and K-band integral field spectra of six luminous ($43.1\lt \log L_{\rm bol}/({\rm erg\, s^{-1}})\lt 44.4$) Seyfert galaxies (NGC 788, Mrk 607, NGC 3227, NGC 3516, NGC 5506, and NGC 5899) in the local Universe (0.0039 < z < 0.0136) to investigate the gas excitation within the inner 100–300 pc radius of the galaxies at spatial resolutions of a few tens of parsecs. In all galaxies, the H2 emission originates from thermal processes with excitation temperatures in the range 2400–5200 K. In the high-line ratio (HLR) region of the H2/Brγ versus [Fe ii]/Paβ diagnostic diagram, which includes 29 per cent of the spaxels, shocks are the main excitation mechanism, as indicated by the correlation between the line widths and line ratios. In the AGN region of the diagram (64 per cent of the spaxels) the H2 emission is due to the AGN radiation. The [Fe ii] emission is produced by a combination of photoionization by the AGN radiation and shocks in five galaxies and is dominated by photoionization in NGC 788. The [S ix]1.2523 μm coronal emission line is present in all galaxies, and its flux distributions are extended from 80 to 185 pc from the galaxy nuclei, except for NGC 5899, in which this line is detected only in the integrated spectrum.

scholarly journals DISCOVERY OF RUBIDIUM, CADMIUM, AND GERMANIUM EMISSION LINES IN THE NEAR-INFRARED SPECTRA OF PLANETARY NEBULAE

2016 ◽  
Vol 819 (1) ◽  
pp. L9 ◽  
Author(s):  
N. C. Sterling ◽  
Harriet L. Dinerstein ◽  
Kyle F. Kaplan ◽  
Manuel A. Bautista
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
Planetary Nebulae ◽  
Emission Lines ◽  
Near Infrared Spectra

scholarly journals The Origin of Weak Emission-Line AGNs

2012 ◽  
Vol 8 (S290) ◽  
pp. 267-268
Author(s):  
Yuan Liu ◽  
Jin Zhang ◽  
Shuang-Nan Zhang
Keyword(s):  
Emission Line ◽  
Optical Spectroscopy ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Early Stage ◽  
Optical Emission ◽  
Emission Lines ◽  
Near Infrared Spectra

AbstractSome abnormal AGNs are discovered in the SDSS data recently. The usual UV/optical emission lines are exceptionally weak in their UV/optical spectroscopy, though the shapes and luminosities of their continua are comparable with that of the normal AGNs. We investigated the optical variations and the near-infrared spectra of these weak emission-line AGNs. We propose that these AGNs can be interpreted as the early stage of an active cycle of AGNs.

scholarly journals The circumstellar environments of B[e] Supergiants

2016 ◽  
Vol 12 (S329) ◽  
pp. 421-421
Author(s):  
G. Maravelias ◽  
M. Kraus ◽  
L. Cidale ◽  
M. L. Arias ◽  
A. Aret ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Loss ◽  
Near Infrared ◽  
Massive Stars ◽  
Complex Environment ◽  
Physical Conditions ◽  
Near Infrared Spectra ◽  
Different Temperatures ◽  
Circumstellar Environments ◽  
Circumstellar Environment

AbstractThe evolution of massive stars encompasses short-lived transition phases in which mass-loss is more enhanced and usually eruptive. A complex environment, combining atomic, molecular and dust regions, is formed around these stars. In particular, the circumstellar environment of B[e] Supergiants is not well understood. To address that, we have initiated a campaign to investigate their environments for a sample of Galactic and Magellanic Cloud sources. Using high-resolution optical and near-infrared spectra (MPG-ESO/FEROS, GEMINI/Phoenix and VLT/CRIRES, respectively), we examine a set of emission features ([OI], [CaII], CO bandheads) to trace the physical conditions and kinematics in their formation regions. We find that the B[e] Supergiants are surrounded by a series of rings of different temperatures and densities, a probable result of previous mass-loss events. In many cases the CO forms very close to the star, while we notice also an alternate mixing of densities and temperatures (which give rise to the different emission features) along the equatorial plane.

Origin of Hot Bubble in NGC 6822 Hubble V Star-Forming Region

2018 ◽  
Vol 14 (S344) ◽  
pp. 96-98
Author(s):  
Hye-In Lee ◽  
Heeyoung Oh ◽  
Beomdu Lim ◽  
Huynh Anh N. Le ◽  
Sungho Lee ◽  
...  
Keyword(s):  
Near Infrared ◽  
Three Dimensional ◽  
Emission Lines ◽  
Spectral Mapping ◽  
Stellar Cluster ◽  
Star Forming ◽  
Bubble Structure ◽  
Ngc 6822 ◽  
Hydrogen Lines ◽  
Slit Scanning

AbstractWe observed a bright H II complex, Hubble V in NGC 6822, using the high-resolution near-infrared spectrograph IGRINS (R = 45,000) attached on the 2.7 m telescope at the McDonald Observatory. We carried out a spectral mapping over a 15″ × 18″ region in the H and K bands using a slit-scanning technique. The emission lines Brγ and He i from ionized regions as well as molecular hydrogen lines from photo-dissociation regions (PDRs), were detected. We show three-dimensional maps of the emission lines and discuss the possibility of an expanding hot bubble structure within which many ionized components are around the central stellar cluster.

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