Extinction curves of GRB environment with the X-shooter

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.

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THE OPTICAL-X-RAY–GAMMA-RAY SPECTRAL ENERGY DISTRIBUTIONS OF GEV GAMMA-RAY LOUD BLAZARS AND CONNECTION AMONG LBLs, HBLs AND FSRQs

International Journal of Modern Physics D ◽

10.1142/s0218271803003451 ◽

2003 ◽

Vol 12 (05) ◽

pp. 781-789 ◽

Cited By ~ 9

Author(s):

G. Z. XIE ◽

S. X. DING ◽

H. DAI ◽

E. W. LIANG ◽

H. T. LIU

Keyword(s):

Gamma Ray ◽

High Energy ◽

Spectral Energy ◽

Spectral Indices ◽

Spectral Energy Distributions ◽

Energy Distributions ◽

X Ray ◽

Γ Ray ◽

High Energy Emission ◽

Bl Lacs

In this paper, we introduce a new composite spectral indices αγxγ = αxγ - αγ, and prove [Formula: see text], that means αγxγ is intrinsic. We plot a αxox - αγxγ diagram for 25 Gev γ-ray blazars for which αx and αγ have been provided in the literature, where αxox = αox - αx which was introduced by Sambruna et al. (1996) and proved that it is intrinsic by our previous paper (Xie et al. 2001). Using this new composite color–color (αxox - αγxγ) diagram, we investigated the nature of the HBLs–LBLs relationship, and the BL Lacs–FSRQs relationship, in high-energy emission. The results show that the spectral energy distributions of three subclasses of Gev γ-ray loud blazars are different, but essentially continuous: HBLs and FSRQs occupy separated regions while LBLs bridge the gap between HBLs and FSRQs. The results are consistent with that derived from a low energy color–color(αxox - αoro) diagram by Sambruna et al. (1996) and Xie et al. (2001). However, on the αox - αxγ diagram, FSRQs, LBLs and HBLs occupy same region. Because both αγxγ and αxox are intrinsic, thus, the new connection among HBLs, LBLs and FSRQs obtained by us is intrinsic.

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Spectral energy distributions and some correlations for Fermi blazars

International Journal of Modern Physics A ◽

10.1142/s0217751x15450207 ◽

2015 ◽

Vol 30 (28n29) ◽

pp. 1545020 ◽

Cited By ~ 3

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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The Classifications and Some Correlations for Fermi Blazars

10.20944/preprints201607.0036.v1 ◽

2016 ◽

Author(s):

Junhui Fan ◽

Y Liu ◽

J.H. Yang ◽

C Lin ◽

J.M. Hao

Keyword(s):

Spectral Index ◽

Gamma Ray ◽

Empirical Relation ◽

Peak Frequency ◽

Spectral Energy ◽

Spectral Energy Distributions ◽

Energy Distributions ◽

X Ray ◽

Peak Luminosity ◽

Integrated Luminosity

In a recent paper, we calculate spectral energy distributions (SEDs) for 1425 Fermi blazars, classifications of low synchrotron peak sources (LSPs) if log $\nu_{\rm p} (\rm Hz) \leq $ 14.0, intermediate synchrotron peak sources (ISPs) if $14.0 < \,\log\, \nu_{\rm p} (\rm Hz) \leq 15.3 $, and high synchrotron peak sources (HSPs) if $ \log\, \nu_{\rm p} (\rm Hz) > 15.3$ are made based on 999 logarithms of synchrotron peak frequencies with known redshift, and we obtain an empirical relation to estimate the synchrotron peak frequency, $\nu_{\rm p}^{\rm Eq.}$ from effective spectral indexes $\alpha_{ox}\, {\rm and}\, \alpha_{ro}$ as $\log \nu_{\rm p}^{\rm Eq.} = 16+4.238X $ if $X < 0$, and $\log \nu_{\rm p}^{\rm Eq.} = 16+4.005Y $ if $X > 0$, where $X = 1.0 - 1.262 \alpha_{ro} - 0.623 \alpha_{ox}$, and $Y = 1.0 + 0.034 \alpha_{ro} - 0.978 \alpha_{ox}$ \cite{Fan16}. In the present work, we investigate the correlation between the peak frequency and the radio to X-ray spectral index, that between peak luminosity (integrated luminosity) and $\gamma$-ray/optical luminosity, and that between peak luminosity and integrated luminosity. Some discussions are presented.

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

The Astrophysical Journal ◽

10.1086/374919 ◽

2003 ◽

Vol 590 (1) ◽

pp. 128-148 ◽

Cited By ~ 45

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

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The spectral energy distributions of active galactic nuclei

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319002667 ◽

2019 ◽

Vol 15 (S341) ◽

pp. 21-25

Author(s):

M. J. I. Brown ◽

K. J. Duncan ◽

H. Landt ◽

M. Kirk ◽

C. Ricci ◽

...

Keyword(s):

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Spectral Energy ◽

Wide Field ◽

Spectral Energy Distributions ◽

Energy Distributions ◽

Photometric Redshifts ◽

X Ray ◽

Ongoing Work ◽

Prior Literature

AbstarctWe present ongoing work on the spectral energy distributions (SEDs) of active galactic nuclei (AGNs), derived from X-ray, ultraviolet, optical, infrared and radio photometry and spectroscopy. Our work is motivated by new wide-field imaging surveys that will identify vast numbers of AGNs, and by the need to benchmark AGN SED fitting codes. We have constructed 41 SEDs of individual AGNs and 80 additional SEDs that mimic Seyfert spectra. All of our SEDs span 0.09 to 30μm, while some extend into the X-ray and/or radio. We have tested the utility of the SEDs by using them to generate AGN photometric redshifts, and they outperform SEDs from the prior literature, including reduced redshift errors and flux density residuals.

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Variations of the physical parameters of the blazar Mrk 421 based on analysis of the spectral energy distributions

Publications of the Astronomical Society of Japan ◽

10.1093/pasj/psaa028 ◽

2020 ◽

Vol 72 (3) ◽

Cited By ~ 2

Author(s):

Yurika Yamada ◽

Makoto Uemura ◽

Ryosuke Itoh ◽

Yasushi Fukazawa ◽

Masanori Ohno ◽

...

Keyword(s):

Magnetic Field ◽

Optimal Solution ◽

Spectral Energy ◽

Physical Parameters ◽

Zone Model ◽

Spectral Energy Distributions ◽

Large Area ◽

Energy Distributions ◽

X Ray ◽

The One

Abstract We report on the variations of the physical parameters of the jet observed in the blazar Mrk 421, and discuss the origin of X-ray flares in the jet, based on analysis of several spectral energy distributions (SEDs). The SEDs are modeled using the one-zone synchrotron self-Compton model, its parameters determined using a Markov chain Monte Carlo method. The lack of data at TeV energies means many of the parameters cannot be uniquely determined and are correlated. These are studied in detail. We find that the optimal solution can be uniquely determined only when we apply a constraint to one of four parameters: the magnetic field (B), the Doppler factor, the size of the emitting region, and the normalization factor of the electron energy distribution. We used 31 sets of SEDs from 2009 to 2014 with optical–UV data observed with UVOT/Swift and the Kanata telescope, X-ray data with XRT/Swift, and γ-ray data with the Fermi Large Area Telescope. The result of our SED analysis suggests that, in the X-ray faint state, the emission occurs in a relatively small area (∼1016 cm) with a relatively strong magnetic field (B ∼ 10−1 G). The X-ray bright state shows a tendency opposite to that of the faint state, that is, a large emitting area (∼1018 cm), probably downstream of the jet, and a weak magnetic field (B ∼ 10−3 G). The high X-ray flux was due to an increase in the maximum energy of electrons. On the other hand, the presence of two kinds of emitting areas implies that the one-zone model is unsuitable for reproducing at least part of the observed SEDs.

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