scholarly journals Emission Lines and the Spectral Energy Distributions of Quasars

1997 ◽  
Vol 159 ◽  
pp. 126-129 ◽  
Author(s):  
B.J. Wilkes ◽  
P.J. Green ◽  
S. Mathur ◽  
J.C. McDowell
Keyword(s):  
Spectral Energy Distribution ◽  
Far Infrared ◽  
Active Galaxies ◽  
Emission Lines ◽  
Spectral Energy ◽  
Baldwin Effect ◽  
Energy Distributions ◽  
X Ray ◽  
The Baldwin Effect ◽  
Initial Results

AbstractMany years of study have failed to establish conclusively relationships between a quasar’s spectral energy distribution (SED) and the emission lines it is thought to produce. This is at least partially due to the lack of well-observed SEDs. We present initial results from a line–SED study for a sample of 43 quasars and active galaxies for which we have optical and ultraviolet spectra and far-infrared–X-ray SEDs. We present the results of tests for correlations between line equivalent widths and SED luminosity and slope parameters and compare these results to those from earlier studies. We find that the Baldwin effect is weaker when the luminosity is defined close to the ionizing continuum of that line and conclude that the detailed SED is likely to be important in making further progress.

scholarly journals The Far‐Infrared Spectral Energy Distributions of X‐Ray–selected Active Galaxies

2003 ◽  
Vol 590 (1) ◽  
pp. 128-148 ◽  
Author(s):  
Joanna K. Kuraszkiewicz ◽  
Belinda J. Wilkes ◽  
Eric ◽  
J. Hooper ◽  
Kim K. McLeod ◽  
...  
Keyword(s):  
Far Infrared ◽  
Active Galaxies ◽  
Spectral Energy ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
X Ray ◽  
Infrared Spectral

scholarly journals Tracking the year-to-year variation in the spectral energy distribution of the narrow-line Seyfert 1 galaxy Mrk 335

2020 ◽  
Vol 499 (1) ◽  
pp. 1266-1286 ◽  
Author(s):  
S Tripathi ◽  
K M McGrath ◽  
L C Gallo ◽  
D Grupe ◽  
S Komossa ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Principal Component ◽  
Accretion Disc ◽  
Spectral Energy ◽  
X Rays ◽  
Physical Processes ◽  
Energy Distributions ◽  
X Ray ◽  
The Past ◽  
Over Time

ABSTRACT Multiwavelength monitoring of Mrk 335 with Swift between 2007 and 2019 are used to construct annual spectral energy distributions (SEDs) and track year-to-year changes. Non-contemporaneous archival data prior to 2007 are used to build a bright state SED. In this work, the changes are examined and quantified to build the foundation for future SED modelling. The yearly SEDs trace a downward trend on the average, with the X-ray portion varying significantly and acquiring further lower values in the past two years when compared to the optical/UV portion of SED. The bolometric Eddington ratios derived using optical/UV to X-ray SEDs and the calculated X-ray luminosities show a gradual decrease over the monitoring period. Changes in the parameters over time are examined. Principal component analysis suggests that the primary variability is in the X-ray properties of Mrk 335. When looking at the broader picture of Mrk 335 and its behaviour, the X-rays, accounting most of the variability in the 13-yr data, are possibly driven by physical processes related to the corona or absorption whereas the modest optical–UV variations suggest their origin within the accretion disc. These results are consistent with the previous interpretation of Mrk 335 using the timing analyses on the monitoring data and spectral modelling of deep observations.

scholarly journals Multiwavelength Energy Distributions of Ultraluminous IRAS Galaxies

1994 ◽  
Vol 159 ◽  
pp. 332-332
Author(s):  
D. Rigopoulou ◽  
A. Lawrence
Keyword(s):  
Energy Source ◽  
Star Formation ◽  
Active Galaxies ◽  
Spectral Energy ◽  
Published Data ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Space Density ◽  
X Ray

Ultraluminous IRAS Galaxies (ULG's) have luminosities comparable to quasars while their space density is much higher than that of active galaxies. Much debate has centered around the origin of the energy source for these objects, whether this is a burst of star formation or a hidden quasar. The sample studied here is the Sanders et al. (1988) sample, 10 objects with LFIR ≥ 1012L⊙. We discuss our new observations at X-ray and submm wavelengths together with other published data for some of the objects. Some useful ideas can be gained from comparisons of the shape of the spectral energy distributions (SED's) of the ultraluminous objects with other “archetype” objects such as typical starbursts i.e. M82 or type 2 AGN i.e. NGC1068.

scholarly journals The spectral energy distributions of active galactic nuclei

2019 ◽  
Vol 489 (3) ◽  
pp. 3351-3367 ◽  
Author(s):  
M J I Brown ◽  
K J Duncan ◽  
H Landt ◽  
M Kirk ◽  
C Ricci ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Flux Density ◽  
Galactic Nuclei ◽  
Far Infrared ◽  
Power Laws ◽  
Spectral Energy ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Photometric Redshifts ◽  
X Ray

ABSTRACT We present spectral energy distributions (SEDs) of 41 active galactic nuclei, derived from multiwavelength photometry and archival spectroscopy. All of the SEDs span at least 0.09 to 30 $\mu$m, but in some instances wavelength coverage extends into the X-ray, far-infrared, and radio. For some active galactic nuclei (AGNs) we have fitted the measured far-infrared photometry with greybody models, while radio flux density measurements have been approximated by power laws or polynomials. We have been able to fill some of the gaps in the spectral coverage using interpolation or extrapolation of simple models. In addition to the 41 individual AGN SEDs, we have produced 72 Seyfert SEDs by mixing SEDs of the central regions of Seyferts with galaxy SEDs. Relative to the literature, our templates have broader wavelength coverage and/or higher spectral resolution. We have tested the utility of our SEDs by using them to generate photometric redshifts for 0 < z ≤ 6.12 AGNs in the Boötes field (selected with X-ray, IR, and optical criteria) and, relative to SEDs from the literature, they produce comparable or better photometric redshifts with reduced flux density residuals.

scholarly journals Multiwavelength data for bright active galaxies

2011 ◽  
Vol 7 (S284) ◽  
pp. 237-239
Author(s):  
Areg M. Mickaelian ◽  
Hayk V. Abrahamyan ◽  
Gurgen M. Paronyan ◽  
Gohar S. Harutyunyan
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Active Galaxies ◽  
Photometric Data ◽  
Spectral Energy ◽  
X Rays ◽  
Large Area ◽  
X Ray ◽  
Space Objects ◽  
Cross Correlations

AbstractThe spectral energy distribution (SED) gives a complete picture of the radiation of space objects and may result in correct classifications compared to those based only on optical (or other local) spectra. This is especially crucial for active galaxies, both AGN and Starbursts (SB). For this, multiwavelength (MW) data are needed taken from available surveys and catalogs. We have cross-correlated the Catalogue of quasars and active galaxies with all-sky or large-area MW catalogues, such as X-ray ROSAT (BSC and FSC), UV GALEX (MIS and AIS), optical APM, MAPS, USNO-B1.0, GSC 2.3.2, and SDSS DR8, NIR 2MASS, MIR/FIR WISE, IRAS (PSC and FSC) and AKARI (IRC and FIS), radio GB6, NVSS, FIRST, and WENSS. We have established accurate positions and photometry for a few thousands of objects that appeared in the catalog with poor data, as well as achieved the best astrometric and photometric data for all objects. This allowed correct cross-correlations and establishing correct MW data for these objects. As a result, we obtained 34 photometric points from X-rays to radio and using VO tools built SEDs for some 10,000 bright objects. Some data from other surveys were also used, such as Chandra, XMM, Spitzer, etc. All objects were grouped into several forms of SED and were compared to the known optical classes given in the catalog (QSO, BLL, Sy1, Sy1.2–1.9, Sy2, LINER, SB, and HII). This allowed reveal obscured AGN, as well as find previously misclassified objects. A homogeneous classification for these objects was established. The first part of this project is presented; establishment of accurate positions and photometry and cross-correlations with MW catalogs.

scholarly journals Multi-wavelength campaign on NGC 7469

2018 ◽  
Vol 615 ◽  
pp. A72 ◽  
Author(s):  
M. Mehdipour ◽  
J. S. Kaastra ◽  
E. Costantini ◽  
E. Behar ◽  
G. A. Kriss ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Far Infrared ◽  
Physical Structure ◽  
Spectral Energy ◽  
X Rays ◽  
Coronal Emission ◽  
X Ray ◽  
The Impact ◽  
Ngc 7469

We investigate the physical structure of the active galactic nucleus (AGN) wind in the Seyfert-1 galaxy NGC 7469 through high-resolution X-ray spectroscopy with Chandra HETGS and photoionisation modelling. Contemporaneous data from Chandra, HST, and Swift are used to model the optical-UV-X-ray continuum and determine the spectral energy distribution (SED) at two epochs, 13 yr apart. For our investigation we use new observations taken in December 2015–January 2016, and historical ones taken in December 2002. We study the impact of a change in the SED shape, seen between the two epochs, on the photoionisation of the wind. The HETGS spectroscopy shows that the AGN wind in NGC 7469 consists of four ionisation components, with their outflow velocities ranging from − 400 to − 1800 km s-1. From our modelling we find that the change in the ionising continuum shape between the two epochs results in some variation in the ionisation state of the wind components. However, for the main ions detected in X-rays, the sum of their column densities over all components remains in practice unchanged. For two of the four components, which are found to be thermally unstable in both epochs, we obtain 2 < r < 31 pc and 12 < r < 29 pc using the cooling and recombination timescales. For the other two thermally stable components, we obtain r < 31 pc and r < 80 pc from the recombination timescale. The results of our photoionisation modelling and thermal stability analysis suggest that the absorber components in NGC 7469 are consistent with being a thermally driven wind from the AGN torus. Finally, from analysis of the zeroth-order ACIS/HETG data, we discover that the X-ray emission in the range 0.2–1 keV is spatially extended over 1.5–12′′. This diffuse soft X-ray emission is explained by coronal emission from the nuclear starburst ring in NGC 7469. The star formation rate inferred from this diffuse soft X-ray emission is consistent with those found by far-infrared studies of NGC 7469.

scholarly journals Hyperluminous starburst gives up its secrets

2019 ◽  
Vol 489 (1) ◽  
pp. 427-436 ◽  
Author(s):  
R J Ivison ◽  
M J Page ◽  
M Cirasuolo ◽  
C M Harrison ◽  
V Mainieri ◽  
...  
Keyword(s):  
Rest Frame ◽  
Spectral Energy Distribution ◽  
Imaging Spectroscopy ◽  
Far Infrared ◽  
Host Galaxy ◽  
Spectral Energy ◽  
X Ray ◽  
Dusty Galaxies ◽  
Imaging And Spectroscopy ◽  
Ir Emission

Abstract HATLAS J084933.4 + 021443 was identified as a dusty starburst via its rest-frame far-infrared (far-IR) emission. Multifrequency imaging and spectroscopy revealed a cluster of four dusty galaxies at z = 2.41, covering 80 kpc. Here, we use Atacama Large Millimetre Array to confirm a more distant, fifth protocluster member, and present X-ray and rest-frame optical imaging spectroscopy of the brightest, an unlensed hyperluminous IR galaxy (HyLIRG). The data reveal broad Hα and bright [N ii] lines, and bright X-ray emission, characteristics that betray a Type-1 active galactic nucleus (AGN), strengthening evidence that AGN are ubiquitous amongst HyLIRGs. The accreting black hole is supermassive, Mbh ≈ 2 × 109 M⊙, with little intrinsic absorption, NH ≈ 5 × 1021 cm−2. The X-ray properties suggest the accretion luminosity rivals that of the starburst, yet it is not obvious where this emerges in its panchromatic spectral energy distribution. We outline three scenarios that could give rise to the observed characteristics, and how we might distinguish between them. In the first, we see the AGN through the host galaxy because of the cavity it excavates. In the others, the AGN is not cospatial with the starburst, having been ejected via asymmetric gravitational radiation, or having evolved towards the naked quasar phase in an unseen companion.

Spectral energy distributions and some correlations for Fermi blazars

2015 ◽  
Vol 30 (28n29) ◽  
pp. 1545020 ◽  
Author(s):  
J. H. Fan ◽  
J. H. Yang ◽  
Y. Liu ◽  
W. Cai ◽  
C. Lin
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
X Rays ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
X Ray

In this work, spectral energy distribution has been calculated for a sample of 597 Fermi blazars. Based on the calculation, we proposed a classification for subclasses of blazars as lower synchrotron peak sources (LSPs) if [Formula: see text], intermediate synchrotron peak sources (ISPs) if [Formula: see text], higher synchrotron peak sources (HSPs) if [Formula: see text], ultra higher synchrotron peak sources (UHSPs) if [Formula: see text]. [Formula: see text]-ray luminosity is found correlated with lower energetic wavebands (radio, optical and X-rays). When redshift effect is removed, correlations are still strong for FSRQs; As for BL lacertaes, correlation between [Formula: see text]-ray and radio or between [Formula: see text]-ray and optical band is strong, but that between [Formula: see text]-ray and X-ray is only marginal.

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