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.

scholarly journals A NuSTAR view of powerful γ-ray loud blazars

2019 ◽  
Vol 627 ◽  
pp. A72 ◽  
Author(s):  
G. Ghisellini ◽  
M. Perri ◽  
L. Costamante ◽  
G. Tagliaferri ◽  
T. Sbarrato ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Peak Frequency ◽  
High Energy ◽  
Spectral Energy ◽  
X Rays ◽  
X Ray ◽  
Γ Ray ◽  
The Universe ◽  
Jet Power

We observed three blazars at z >  2 with the NuSTAR satellite. These were detected in the γ-rays by Fermi/LAT and in the soft X-rays, but have not yet been observed above 10 keV. The flux and slope of their X-ray continuum, together with Fermi/LAT data allows us to estimate their total electromagnetic output and peak frequency. For some of them we were able to study the source in different states, and investigate the main cause of the different observed spectral energy distribution. We then collected all blazars at redshifts greater than 2 observed by NuSTAR, and confirm that these hard and luminous X-ray blazars are among the most powerful persistent sources in the Universe. We confirm the relation between the jet power and the disk luminosity, extending it at the high-energy end.

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 Extremely Red Galaxies in Abell 1835

2006 ◽  
Vol 2 (S235) ◽  
pp. 204-204
Author(s):  
A. Hempel ◽  
D. Schaerer ◽  
J. Richard ◽  
E. Egami ◽  
R. Pelló
Keyword(s):  
Energy Distribution ◽  
Gravitational Lensing ◽  
Spectral Energy Distribution ◽  
Optical Detection ◽  
Spectral Energy ◽  
Colour Properties ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Red Galaxies

AbstractWe use multi-colour data of the gravitational lensing cluster Abell 1835 to search for high-z candidates (Richard et al. 2006) and extremely red galaxies.Applying a colour criteria of R-K ≥ 5.6 we have selected 12 EROs, of which 10(9) have no R(I)-band detection. Two of these sources posses multiple detections in the ACS z850 band, possibly gravitationally bound objects.Using the method of Pozzetti and Mannucci (2000) to classify an ERO either as evolved elliptical or dusty starburst, we find that two thirds of all objects have colours assigned to evolved ellipticals. One of the remaining 4 sources is the known sub-mm source SMMJ14009+0252.The spectral energy distributions of sources with no optical detection show strong similarities to the SED of the high-z object of Mobasher et al. (2005), i.e. a degeneracy between a low- and high-z solution. However, for objects we accept the low-z solution as the better fit.A detailed analyses of the colour properties and spectral energy distribution will be published in two forthcoming papers (Schaerer et al., Hempel et al.).

scholarly journals Spectral Energy Distribution of Be Stars

1987 ◽  
Vol 92 ◽  
pp. 206-207
Author(s):  
Dieter Kaiser ◽  
Reinhard W. Hanuschik
Keyword(s):  
Energy Distribution ◽  
Wavelength Range ◽  
Spectral Resolution ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Be Stars ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
The University

During two observation periods in Nov./Dec. 1981 and April/ May 1985, absolute spectral energy distributions of 41 southern and equatorial Be stars were photometrically measured at 10 Å spectral resolution in the wavelength range between 3200 Å and 8500 Å, using the scanning spectrophotometer attached to the 61 cm telescope of the University of Bochum at La Silla/Chile. Spectral fluxes of the program stars have been determined with an error of 0m.03 or less.

scholarly journals Extinction curves of GRB environment with the X-shooter

2015 ◽  
Vol 11 (A29B) ◽  
pp. 253-254
Author(s):  
Andreja Gomboc ◽  
Jure Japelj ◽  
Stefano Covino
Keyword(s):  
Rest Frame ◽  
Near Infrared ◽  
Gamma Ray ◽  
Spectral Energy ◽  
X Rays ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
X Ray ◽  
Unique Probe ◽  
Photometric Measurements

AbstractGamma Ray Bursts (GRBs) can be used as a powerful tool to study galactic environments at different epochs of the Universe's evolution, thanks to their bright afterglow emission ranging from X-rays to optical and radio wavebands. Important aspect of the environment is dust, which plays a central role in the astrophysical processes of interstellar medium and in the formation of stars. GRBs can be a unique probe of dust at cosmological distances, where its origin and properties are still poorly known. By using a sample of GRB afterglow spectra observed with the VLT/X-shooter spectrograph we studied the rest-frame extinction in GRB lines-of-sight by modelling the broadband near-infrared to X-ray afterglow spectral energy distributions. We present our results on the rest-frame extinction of our sample, and illustrate that the spectroscopic data, thanks to a combination of excellent resolution and coverage of the blue part of the spectral energy distributions, are more successful than photometric measurements in constraining the extinction curves and therefore the dust properties in GRB hosts.

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 Hard X-ray-to-radio energy distributions in starburst galaxies

1999 ◽  
Vol 193 ◽  
pp. 592-593 ◽  
Author(s):  
Miguel Cerviño ◽  
J. Miguel Mas-Hesse
Keyword(s):  
Energy Distribution ◽  
Mechanical Energy ◽  
Spectral Energy Distribution ◽  
High Energy ◽  
Starburst Galaxies ◽  
Spectral Energy ◽  
X Rays ◽  
X Ray ◽  
High Energy Emission ◽  
X Ray Binaries

We present in this contribution the predictions on the multiwavelength spectral energy distribution of our evolutionary population synthesis models including single and binary stellar systems. The high energy computations include the emission associated to X-ray binaries and supernovae remnants, as well as the mechanical energy released into the interstellar medium, which can be partially reprocessed into thermal X-rays. With these components we compute the spectral energy distribution of starburst galaxies from X-ray to radio ranges, and analyze finally the effects of the high energy emission on the H and He ionizing continuum.

scholarly journals The population of young stars in Orion A: X-rays and IR properties

2009 ◽  
Vol 5 (S266) ◽  
pp. 509-509
Author(s):  
Ignazio Pillitteri ◽  
S. J. Wolk ◽  
L. Allen ◽  
S. T. Megeath ◽  
R. A. Gutermuth ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Young Stars ◽  
Spectral Energy ◽  
X Rays ◽  
Infrared Excess ◽  
X Ray ◽  
Young Stellar Object ◽  
Formation History ◽  
Distribution Class

AbstractStars in the very early stages of their formation are characterized by strong infrared excess and X-ray emission. We present the results of the survey of Orion A in both the infrared and X-rays obtained with the Spitzer and XMM/Newton observatories. We study the spectral-energy distribution class of the young stellar object (YSO) population using infrared colors from 2mass and Spitzer (IRAC and MIPS) and by means of X-ray fluxes, luminosities and plasma temperatures. We discuss clustering properties and spatial segregation among different infrared YSO classes to trace their formation history.

scholarly journals The Influence of Forming Companions on the Spectral Energy Distributions of Stars with Circumstellar Discs

2017 ◽  
Vol 34 ◽  
Author(s):  
Olga V. Zakhozhay
Keyword(s):  
Energy Distribution ◽  
Radiative Transfer Equation ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Brown Dwarf ◽  
Spectral Energy Distributions ◽  
Distribution Profile ◽  
Energy Distributions ◽  
One Dimensional ◽  
The One

AbstractWe study a possibility to detect signatures of brown dwarf companions in a circumstellar disc based on spectral energy distributions. We present the results of spectral energy distribution simulations for a system with a 0.8 M⊙ central object and a companion with a mass of 30 MJ embedded in a typical protoplanetary disc. We use a solution to the one-dimensional radiative transfer equation to calculate the protoplanetary disc flux density and assume, that the companion moves along a circular orbit and clears a gap. The width of the gap is assumed to be the diameter of the brown dwarf Hill sphere. Our modelling shows that the presence of such a gap can initiate an additional minimum in the spectral energy distribution profile of a protoplanetary disc at λ = 10–100 μm. We found that it is possible to detect signatures of the companion when it is located within 10 AU, even when it is as small as 3 MJ. The spectral energy distribution of a protostellar disc with a massive fragment (of relatively cold temperature ~400 K) might have a similar double peaked profile to the spectral energy distribution of a more evolved disc that contains a gap.

scholarly journals Particle acceleration in low-power hotspots: modelling the broad-band spectral energy distribution

2020 ◽  
Vol 495 (2) ◽  
pp. 1593-1607 ◽  
Author(s):  
G Migliori ◽  
M Orienti ◽  
L Coccato ◽  
G Brunetti ◽  
F D’Ammando ◽  
...  
Keyword(s):  
Particle Acceleration ◽  
Energy Distribution ◽  
Low Power ◽  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Broad Band ◽  
Spectral Energy ◽  
X Rays ◽  
X Ray ◽  
Radiative Processes

ABSTRACT The acceleration and radiative processes active in low-power radio hotspots are investigated by means of new deep near-infrared (NIR) and optical Very Large Telescope (VLT) observations, complemented with archival, high-sensitivity VLT, radio Very Large Array (VLA), and X-ray Chandra data. For the three studied radio galaxies (3C 105, 3C 195, and 3C 227), we confirm the detection of NIR/optical counterparts of the observed radio hotspots. We resolve multiple components in 3C 227 West and in 3C 105 South and characterize the diffuse NIR/optical emission of the latter. We show that the linear size of this component (≳4 kpc) makes 3C 105 South a compelling case for particles’ re-acceleration in the post-shock region. Modelling of the radio-to-X-ray spectral energy distribution (SED) of 3C 195 South and 3C 227 W1 gives clues on the origin of the detected X-ray emission. In the context of inverse Compton models, the peculiarly steep synchrotron curve of 3C 195 South sets constraints on the shape of the radiating particles’ spectrum that are testable with better knowledge of the SED shape at low (≲GHz) radio frequencies and in X-rays. The X-ray emission of 3C 227 W1 can be explained with an additional synchrotron component originating in compact (<100 pc) regions, such those revealed by radio observations at 22 GHz, provided that efficient particle acceleration (γ ≳ 107) is ongoing. The emerging picture is that of systems in which different acceleration and radiative processes co-exist.

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