Photoionization models and diagnosis of physical properties of the broad-line emission gas in quasars and Seyfert nuclei

1984 ◽  
Vol 283 ◽  
pp. 70 ◽  
Author(s):  
J. Kwan
Keyword(s):  
Physical Properties ◽  
Line Emission ◽  
Broad Line

Polarization of broad line emission in radio galaxies

2019 ◽  
Vol 340 (5) ◽  
pp. 445-448
Author(s):  
Mikhail Y. Piotrovich ◽  
Stanislava D. Buliga ◽  
Tinatin M. Natsvlishvili ◽  
Yuri N. Gnedin
Keyword(s):  
Line Emission ◽  
Radio Galaxies ◽  
Broad Line

scholarly journals Velocity profiles of [CII], [CI], CO, and [OI] and physical conditions in four star-forming regions in the Large Magellanic Cloud

2019 ◽  
Vol 621 ◽  
pp. A62 ◽  
Author(s):  
Yoko Okada ◽  
Rolf Güsten ◽  
Miguel Angel Requena-Torres ◽  
Markus Röllig ◽  
Jürgen Stutzki ◽  
...  
Keyword(s):  
Physical Properties ◽  
High Redshift ◽  
Line Emission ◽  
Chemical Species ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Continuum Emission ◽  
Line Profiles ◽  
Star Forming ◽  
Star Forming Regions

Aims. The aim of our study is to investigate the physical properties of the star-forming interstellar medium (ISM) in the Large Magellanic Cloud (LMC) by separating the origin of the emission lines spatially and spectrally. The LMC provides a unique local template to bridge studies in the Galaxy and high redshift galaxies because of its low metallicity and proximity, enabling us to study the detailed physics of the ISM in spatially resolved individual star-forming regions. Following Okada et al. (Okada, Y., Requena-Torres, M. A., Güsten, R., et al. 2015, A&A, 580, A54), we investigate different phases of the ISM traced by carbon-bearing species in four star-forming regions in the LMC, and model the physical properties using the KOSMA-τ PDR model. Methods. We mapped 3–13 arcmin2 areas in 30 Dor, N158, N160, and N159 along the molecular ridge of the LMC in [C II] 158 μm with GREAT on board SOFIA. We also observed the same area with CO(2-1) to (6-5), 13CO(2-1) and (3-2), [C I] 3P1–3P0 and 3P2–3P1 with APEX. For selected positions in N159 and 30 Dor, we observed [O I] 145 μm and [O I] 63 μm with upGREAT. All spectra are velocity resolved. Results. In all four star-forming regions, the line profiles of CO, 13CO, and [C I] emission are similar, being reproduced by a combination of Gaussian profiles defined by CO(3-2), whereas [C II] typically shows wider line profiles or an additional velocity component. At several positions in N159 and 30 Dor, we observed the velocity-resolved [O I] 145 and 63 μm lines for the first time. At some positions, the [O I] line profiles match those of CO, at other positions they are more similar to the [C II] profiles. We interpret the different line profiles of CO, [C II] and [O I] as contributions from spatially separated clouds and/or clouds in different physical phases, which give different line ratios depending on their physical properties. We modeled the emission from the CO, [C I], [C II], and [O I] lines and the far-infrared continuum emission using the latest KOSMA-τ PDR model, which treats the dust-related physics consistently and computes the dust continuum SED together with the line emission of the chemical species. We find that the line and continuum emissions are not well-reproduced by a single clump ensemble. Toward the CO peak at N159 W, we propose a scenario that the CO, [C II], and [O I] 63 μm emission are weaker than expected because of mutual shielding among clumps.

scholarly journals Properties of LBGs with [OIII] detection at z ∼ 3.5

2019 ◽  
Vol 631 ◽  
pp. A123 ◽  
Author(s):  
Fang-Ting Yuan ◽  
Denis Burgarella ◽  
David Corre ◽  
Veronique Buat ◽  
Médéric Boquien ◽  
...  
Keyword(s):  
Physical Properties ◽  
Emission Line ◽  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Line Emission ◽  
Stellar Mass ◽  
Spectral Energy ◽  
Emission Data ◽  
The Impact

Context. Nebular emission lines are critical to measure physical properties in the ionized gas (e.g., metallicity, the star formation rate, or dust attenuation). They also account for a significant fraction of broadband fluxes, in particular at the highest redshifts, and therefore can strongly affect the determination of other physical properties, such as the stellar mass, which are crucial in shaping our understanding of galaxy formation and evolution. Aims. We investigate a sample of 51 Lyman break galaxies at 3.0 <  zspec <  3.8 with detected [OIII] line emissions and estimated the physical properties of these galaxies to examine the impact of including nebular emission data in the Spectral energy distribution (SED) fitting. Methods. We used the Code Investigating GALaxy Emission (CIGALE) to fit the rest-frame ultraviolet-to-near-infrared SEDs of these galaxies and their emission line data simultaneously. We ran CIGALE with and without the nebular model or the emission line data, and compare the results to show the importance of including the nebular emission line data in the SED fitting. Results. We find that without the nebular model, the SED fitting overestimates the stellar mass due to the strong [OIII] lines that are redshifted to the Ks-band, which is consistent with previous results. The emission line data are necessary to constrain the nebular model in the SED fitting. We examine the Ks-band excess, which is mostly used to estimate the emissions of the [OIII]+Hβ lines when there is no spectral data, and we find that the estimation and observation are statistically consistent. However, the difference can reach up to more than 1 dex in some catastrophic cases, which shows the importance of obtaining spectroscopic measurements for these lines. We also estimate the equivalent width of the Hβ absorption and find it negligible compared to the Hβ emission. Conclusions. Line emission is important to constrain the nebular models and to obtain reliable estimates of the physical properties of galaxies. These data should be taken into account in the SED fitting.

scholarly journals Space Telescope and Optical Reverberation Mapping Project: A Leap Forward in Reverberation Mapping

2016 ◽  
Vol 12 (S324) ◽  
pp. 215-218 ◽  
Author(s):  
Bradley M. Peterson
Keyword(s):  
World Wide ◽  
Hubble Space Telescope ◽  
Line Emission ◽  
Broad Line ◽  
Space Telescope ◽  
Reverberation Mapping ◽  
Significant Challenge ◽  
Past Behavior ◽  
Line Region ◽  
Mapping Program

AbstractIn 2014, a 179-orbit allocation of Hubble Space Telescope time anchored a massive reverberation-mapping program on the well-studied Seyfert 1 galaxy NGC 5548. Supporting imaging and spectrophotometric observations were provided by Swift, Chandra, Spitzer, and a world-wide network of ground-based telescopes. Understanding the data remains a significant challenge, partly because the level of detail is far beyond what has been seen before and partly because the behavior of the AGN was not typical of its past behavior. Based on analysis to date, the following conclusions can be reached: (1) the AGN accretion disk has a temperature profile that is consistent with that predicted by the Shakura–Sunyaev model, but is about three times larger than expected; (2) at least part of the broad-line region appears to be a Keplerian disk seen at intermediate inclination, and (3) the broad-line emission response from the far side of the disk is weaker than expected.

scholarly journals Polarized Broad‐Line Emission from Low‐Luminosity Active Galactic Nuclei

1999 ◽  
Vol 525 (2) ◽  
pp. 673-684 ◽  
Author(s):  
Aaron J. Barth ◽  
Alexei V. Filippenko ◽  
Edward C. Moran
Keyword(s):  
Active Galactic Nuclei ◽  
Line Emission ◽  
Galactic Nuclei ◽  
Broad Line

scholarly journals The 6m mm-VLBI telescope at Kagoshima, Japan

1994 ◽  
Vol 140 ◽  
pp. 64-65
Author(s):  
Toshihiro Omodaka ◽  
Masaki Morimoto ◽  
Noriyuki Kawaguchi ◽  
Yoshimi Kitamura ◽  
Minoru Tanaka ◽  
...  
Keyword(s):  
Line Emission ◽  
Active Galaxies ◽  
Broad Line ◽  
Urgent Problem ◽  
Massive Black Holes ◽  
High Resolution Mapping ◽  
Millimeter Wavelengths ◽  
Vlbi Observations ◽  
Resolution Mapping ◽  
Under Construction

VLBI observations of millimeter wavelengths can probe the broad line emission and jet forming regions of quasars, and the scale of an accretion disk around massive black holes in nearby active galaxies, which are self-absorbed at longer wavelengths. Therefore, the extension of the mm-VLBI network is timely and urgent problem. We are now planning to move Nobeyama 6 m mm VLBI telescope to Kagoshima. The telescope will be placed at Kinkohwan park in Kagoshima City in late 1992 and will be operated in 1993. The frequencies for VLBI observations will range from 22 GHz to 100 GHz.To date, there are two mm-VLBI facilities in Japan: Nobeyama 45 m and Kashima 34 m, However, the longest baseline is only about 200km EW which provides a fringe separation of 17 mas. This is not sufficient for high resolution mapping. A 10 m telescope which is under construction at Mizusawa, 400 km north from Kashima which will be usable up to 43 GHz and will add a north-south baseline, which is very important for astrometrie measurement.

scholarly journals Peculiar emission line spectra of core extremely red BOSS quasars at z∼2–3: orientation and/or evolution?

2020 ◽  
Vol 634 ◽  
pp. A116 ◽  
Author(s):  
M. Villar Martín ◽  
M. Perna ◽  
A. Humphrey ◽  
N. Castro Rodríguez ◽  
L. Binette ◽  
...  
Keyword(s):  
Emission Line ◽  
Near Infrared ◽  
Outer Part ◽  
Line Emission ◽  
Optical Emission ◽  
Broad Line ◽  
Broad Line Region ◽  
Line Region ◽  
Evolutionary Phase

Context. Core extremely red quasars (core ERQ) have been proposed to represent an intermediate evolutionary phase in which a heavily obscured quasar blows out the circumnuclear interstellar medium with very energetic outflows before it becomes an optical quasar. Aims. We investigate whether the properties of core ERQ fit the AGN orientation-based unification scenario. Methods. We revised the general UV and optical emission line properties of core ERQ in the context of the orientation-based scenario. We used diagnostic diagrams based on UV emission line ratios and UV-to-optical line kinematic information to compare the physical and kinematic gas properties of core ERQ with those of other luminous narrow- and broad-line AGN. In particular, we provide a revised comparison of the [OIII] kinematics in 21 core ERQ (20 from Perrotta et al. 2019, MNRAS, 488, 4126 and SDSS J171420.38+414815.7, based on GTC EMIR near-infrared spectroscopy) with other samples of quasars with matching luminosity with the aim of evaluating whether core ERQ host the most extreme [OIII] outflows. Results. The UV line ratios suggest that the physical properties (e.g., density and metallicity) of the ionised gas in core ERQ are similar to those observed in the broad-line region of blue nitrogen-loud quasars. The [OIII] outflow velocities of core ERQ are on average consistent with those of very luminous blue type 1 quasars, although extreme outflows are much more frequent in core ERQ. These similarities can be explained in the context of the AGN unification model under the assumption that core ERQ are viewed with an intermediate orientation between type 2 (edge-on) and type 1 (face-on) quasars. Conclusions. We propose that core ERQ are very luminous but otherwise normal quasars viewed at an intermediate orientation. This orientation allows a direct view of the outer part of the large broad-line region from which core ERQ UV line emission originates; the extreme [OIII] outflow velocities are instead a consequence of the very high luminosity of core ERQ.

scholarly journals The broad line emission from the AGN 3C 390.3: complex broad-line region and perturbation in accretion disk

2012 ◽  
Vol 8 (S290) ◽  
pp. 205-206
Author(s):  
Ilić Dragana ◽  
Luka Č. Popović ◽  
Alla I. Shapovalova ◽  
Alexander N. Burenkov ◽  
Vahram H. Chavushyan ◽  
...  
Keyword(s):  
Emission Line ◽  
Accretion Disk ◽  
Radio Galaxy ◽  
Dominant Role ◽  
Line Emission ◽  
Broad Line ◽  
Line Profiles ◽  
Broad Emission ◽  
Line Region ◽  
Present Part

AbstractFrom 13-years of the spectral optical monitoring of a well-known broad-line radio galaxy 3C 390.3 we concluded that the geometry of the broad emission-line region is complex, while still the main part of the emission is coming from the accretion disk. Here we present part of the analysis of the broad Hα and Hβ emission lines, which are showing highly variable double-peaked profiles during the monitoring period (1995-2007), with the aim to probe the accretion disk properties. The disk-like geometry plays a dominant role, but the variability of Hα and Hβ line profiles and intensities shows a presence of an additional emission-line region, that has a different nature for different periods, e.g. in one period the observed variation can be well modeled if one assumes changes in position and size of the emitting disk along the accretion disk.

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