scholarly journals A review of spectral energy distribution modeling at high-redshift

2019 ◽  
Vol 15 (S352) ◽  
pp. 77-77
Author(s):  
Stéphane Charlot
Keyword(s):  
Interstellar Medium ◽  
Energy Distribution ◽  
Rest Frame ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Optical Emission ◽  
Spectral Energy ◽  
Distribution Modeling ◽  
Redshift Galaxy ◽  
Recent Developments

AbstractI will review recent developments in the modeling of high-redshift galaxy spectra, focusing in particular on the rest-frame ultraviolet and optical emission from young stellar populations and the interstellar medium.

scholarly journals AGILE, Fermi, Swift, and GASP/WEBT multi-wavelength observations of the high-redshift blazar 4C +71.07 in outburst

2019 ◽  
Vol 621 ◽  
pp. A82 ◽  
Author(s):  
S. Vercellone ◽  
P. Romano ◽  
G. Piano ◽  
V. Vittorini ◽  
I. Donnarumma ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Near Infrared ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Optical Emission ◽  
High Mass ◽  
Spectral Energy ◽  
Emission Region ◽  
Energy Bands ◽  
Spectrum Radio

Context. The flat-spectrum radio quasar 4C +71.07 is a high-redshift (z = 2.172), γ-loud blazar whose optical emission is dominated by thermal radiation from the accretion disc. Aims. 4C +71.07 has been detected in outburst twice by the AGILE γ-ray satellite during the period from the end of October to mid-November 2015, when it reached a γ-ray flux of the order of F(E >  100 MeV)=(1.2 ± 0.3)×10−6 photons cm−2 s−1 and F(E > 100 MeV)=(3.1 ± 0.6)×10−6 photons cm−2 s−1, respectively, allowing us to investigate the properties of the jet and the emission region. Methods. We investigated its spectral energy distribution by means of almost-simultaneous observations covering the cm, mm, near-infrared, optical, ultraviolet, X-ray, and γ-ray energy bands obtained by the GASP-WEBT Consortium and the Swift, AGILE, and Fermi satellites. Results. The spectral energy distribution of the second γ-ray flare (whose energy coverage is more dense) can be modelled by means of a one-zone leptonic model, yielding a total jet power of about 4 × 1047 erg s−1. Conclusions. During the most prominent γ-ray flaring period our model is consistent with a dissipation region within the broad-line region. Moreover, this class of high-redshift, flat-spectrum radio quasars with high-mass black holes might be good targets for future γ-ray satellites such as e-ASTROGAM.

scholarly journals Spectral energy distribution similarity of the local galaxies and the 3.6 μm selected galaxies from the Spitzer Extended Deep Survey

2021 ◽  
Vol 21 (10) ◽  
pp. 260
Author(s):  
Cheng Cheng ◽  
Jia-Sheng Huang ◽  
Hai Xu ◽  
Gao-Xiang Jin ◽  
Chuan He ◽  
...  
Keyword(s):  
High Redshift ◽  
Spectral Energy Distribution ◽  
Mass Function ◽  
Spectral Energy ◽  
Energy Distributions ◽  
Mid Infrared ◽  
Redshift Galaxy ◽  
The Galaxy ◽  
Deep Survey ◽  
Multi Wavelength

Abstract The Spitzer Extended Deep Survey (SEDS) as a deep and wide mid-infrared (MIR) survey project provides a sample of 500 000+ sources spreading 1.46 square degree and a depth of 26 AB mag (3σ). Combining with the previous available data, we build a PSF-matched multi-wavelength photometry catalog from u band to 8 μm. We fit the SEDS galaxies spectral energy distributions by the local galaxy templates. The results show that the SEDS galaxy can be fitted well, indicating the high redshift galaxy (z ∼ 1) shares the same templates with the local galaxies. This study would facilitate the further study of the galaxy luminosity and high redshift mass function.

scholarly journals Serendipitous discovery of an “ALMA-only” galaxy at 5 < z < 6 in an ALMA 3-mm survey

2019 ◽  
Vol 15 (S352) ◽  
pp. 194-198
Author(s):  
Christina C. Williams
Keyword(s):  
Star Formation ◽  
Energy Distribution ◽  
Star Formation Rate ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Spectral Energy ◽  
Large Contribution ◽  
Massive Galaxies ◽  
Multi Wavelength

AbstractWe discuss the serendipitous discovery of a dusty high-redshift galaxy in a small (8 arcmin2) ALMA 3-mm survey Williams et al. (2019). The galaxy was previously unknown and is absent from existing multi-wavelength catalogs (“ALMA-only”). Using the ALMA position as prior, we perform forced deblended photometry to constrain its spectral energy distribution. The spectral energy distribution is well described by a massive (M* = 1010.8 M⊙) and highly obscured (AV ∼ 4) galaxy at redshift z = 5.5 ± 1.1 with star formation rate ∼ 300 M⊙yr−1. Our small survey area implies an uncertain but large contribution to the cosmic star formation rate density, similar to the contribution from all ultraviolet-selected galaxies combined at this redshift. This galaxy likely traces an abundant population of massive galaxies absent from current samples of infrared-selected or sub-millimeter galaxies, but with larger space densities, higher duty cycles, and significant contribution to the cosmic star-formation rate and stellar mass densities.

scholarly journals NuSTAROBSERVATIONS AND BROADBAND SPECTRAL ENERGY DISTRIBUTION MODELING OF THE MILLISECOND PULSAR BINARY PSR J1023+0038

2014 ◽  
Vol 797 (2) ◽  
pp. 111 ◽  
Author(s):  
K. L. Li ◽  
A. K. H. Kong ◽  
J. Takata ◽  
K. S. Cheng ◽  
P. H. T. Tam ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Millisecond Pulsar ◽  
Distribution Modeling

scholarly journals The VLA-COSMOS 3 GHz Large Project: Average radio spectral energy distribution of highly star-forming galaxies

2019 ◽  
Vol 621 ◽  
pp. A139 ◽  
Author(s):  
K. Tisanić ◽  
V. Smolčić ◽  
J. Delhaize ◽  
M. Novak ◽  
H. Intema ◽  
...  
Keyword(s):  
Survival Analysis ◽  
Energy Distribution ◽  
Power Law ◽  
Rest Frame ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Radio Luminosity ◽  
Star Forming ◽  
The Impact ◽  
Frame Frequency

We construct the average radio spectral energy distribution (SED) of highly star-forming galaxies (HSFGs) up to z ∼ 4. Infrared and radio luminosities are bound by a tight correlation that is defined by the so-called q parameter. This infrared–radio correlation provides the basis for the use of radio luminosity as a star-formation tracer. Recent stacking and survival analysis studies find q to be decreasing with increasing redshift. It was pointed out that a possible cause of the redshift trend could be the computation of rest-frame radio luminosity via a single power-law assumption of the star-forming galaxies’ (SFGs) SED. To test this, we constrained the shape of the radio SED of a sample of HSFGs. To achieve a broad rest-frame frequency range, we combined previously published Very Large Array observations of the COSMOS field at 1.4 GHz and 3 GHz with unpublished Giant Meterwave Radio Telescope (GMRT) observations at 325 MHz and 610 MHz by employing survival analysis to account for non-detections in the GMRT maps. We selected a sample of HSFGs in a broad redshift range (z ∈ [0.3, 4],  SFR ≥ 100 M⊙ yr−1) and constructed the average radio SED. By fitting a broken power-law, we find that the spectral index changes from α1 = 0.42 ± 0.06 below a rest-frame frequency of 4.3 GHz to α2 = 0.94 ± 0.06 above 4.3 GHz. Our results are in line with previous low-redshift studies of HSFGs ( SFR >  10 M⊙  yr−1) that show the SED of HSFGs to differ from the SED found for normal SFGs ( SFR <  10 M⊙ yr−1). The difference is mainly in a steeper spectrum around 10 GHz, which could indicate a smaller fraction of thermal free–free emission. Finally, we also discuss the impact of applying this broken power-law SED in place of a simple power-law in K-corrections of HSFGs and a typical radio SED for normal SFGs drawn from the literature. We find that the shape of the radio SED is unlikely to be the root cause of the q − z trend in SFGs.

HIGH-REDSHIFT DUST OBSCURED GALAXIES: A MORPHOLOGY-SPECTRAL ENERGY DISTRIBUTION CONNECTION REVEALED BY KECK ADAPTIVE OPTICS

2009 ◽  
Vol 137 (6) ◽  
pp. 4854-4866 ◽  
Author(s):  
J. Melbourne ◽  
R. S. Bussman ◽  
K. Brand ◽  
V. Desai ◽  
L. Armus ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Adaptive Optics ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Spectral Energy

scholarly journals Companions to High Redshift Quasars

1992 ◽  
Vol 9 ◽  
pp. 693-694
Author(s):  
Esther M. Hu
Keyword(s):  
Energy Distribution ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Radio Sources ◽  
Color Imaging ◽  
Radio Studies ◽  
Companion Systems

AbstractLyman a companions to high-redshift quasars appear associated with radio activity in the quasar. Of the five known companion systems seen at typical Lα fluxes of a few x 10-16 ergs cm-2 sec-1, all are associated with quasars which are radio sources, and lie within a few arcseconds of the quasar. We summarize results of searches for the companions, and report on subsequent investigations into the spectral energy distribution and radio studies of these objects. Multi-color imaging from 3400 Å to 2.2/μ shows the companion to PKS 1614+051 possesses a blue SED similar to an irregular at that redshift. VLA observations show double-lobed structure around Q1033+137 with depolarization of the counterjet lobe.

scholarly journals Investigation of the γ-ray spectrum of CTA 102 during the exceptional flaring state in 2016–2017

2020 ◽  
Vol 635 ◽  
pp. A25 ◽  
Author(s):  
N. Sahakyan
Keyword(s):  
Energy Distribution ◽  
Power Law ◽  
Spectral Energy Distribution ◽  
Optical Emission ◽  
Extended Period ◽  
Spectral Energy ◽  
Large Area ◽  
Inverse Compton Scattering ◽  
Line Region ◽  
Photon Index

The flat spectrum radio quasar CTA 102 entered an extended period of activity from 2016 to 2017 during which several strong γ-ray flares were observed. By using Fermi large area telescope data, a detailed investigation of γ-ray spectra of CTA 102 during the flaring period was performed. In several periods, the γ-ray spectrum is not consistent with a simple power-law, having a hard photon index with an index of ∼(1.8−2.0) that shows a spectral cut-off around an observed photon energy of ∼(9−16) GeV. The internal γ-ray absorption via photon-photon pair production on the broad-line-region-reflected photons cannot account for the observed cut-off and break even if the emitting region is very close to the central source. This cut-off and break are likely due to a similar intrinsic break in the energy distribution of emitting particles. The origin of the spectral break is investigated through the multiwavelength modeling of the spectral energy distribution in considering a different location for the emitting region. The observed X-ray and γ-ray data is modeled as inverse Compton scattering of synchrotron and/or external photons on the electron population that produces the radio-to-optical emission, which allowed to constrain the power-law index and cut-off energy in the electron energy distribution. The obtained results are discussed in the context of a diffusive acceleration of electrons in the CTA 102 jet.

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