scholarly journals Measuring the Average Evolution of Luminous Galaxies atz< 3: The Rest‐Frame Optical Luminosity Density, Spectral Energy Distribution, and Stellar Mass Density

2006 ◽  
Vol 650 (2) ◽  
pp. 624-643 ◽  
Author(s):  
Gregory Rudnick ◽  
Ivo Labbe ◽  
Natascha M. Forster Schreiber ◽  
Stijn Wuyts ◽  
Marijn Franx ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Rest Frame ◽  
Mass Density ◽  
Spectral Energy Distribution ◽  
Stellar Mass ◽  
Spectral Energy ◽  
Luminous Galaxies

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range, we combined previously published Very Large Array observations of the COSMOS field at 1.4 GHz and 3 GHz with unpublished Giant Meterwave Radio Telescope (GMRT) observations at 325 MHz and 610 MHz by employing survival analysis to account for non-detections in the GMRT maps.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.

scholarly journals Galaxy And Mass Assembly (GAMA): a forensic SED reconstruction of the cosmic star formation history and metallicity evolution by galaxy type

2020 ◽  
Vol 498 (4) ◽  
pp. 5581-5603
Author(s):  
Sabine Bellstedt ◽  
Aaron S G Robotham ◽  
Simon P Driver ◽  
Jessica E Thorne ◽  
Luke J M Davies ◽  
...  
Keyword(s):  
Star Formation ◽  
Gas Phase ◽  
Mass Density ◽  
Spectral Energy Distribution ◽  
Stellar Mass ◽  
Star Formation History ◽  
Spectral Energy ◽  
Massive Galaxies ◽  
Formation History ◽  
The Universe

ABSTRACT We apply the spectral energy distribution (SED) fitting code ProSpect to multiwavelength imaging for ∼7000 galaxies from the GAMA survey at z &lt; 0.06, in order to extract their star formation histories. We combine a parametric description of the star formation history with a closed-box evolution of metallicity where the present-day gas-phase metallicity of the galaxy is a free parameter. We show with this approach that we are able to recover the observationally determined cosmic star formation history (CSFH), an indication that stars are being formed in the correct epoch of the Universe, on average, for the manner in which we are conducting SED fitting. We also show the contribution to the CSFH of galaxies of different present-day visual morphologies and stellar masses. Our analysis suggests that half of the mass in present-day elliptical galaxies was in place 11 Gyr ago. In other morphological types, the stellar mass formed later, up to 6 Gyr ago for present-day irregular galaxies. Similarly, the most massive galaxies in our sample were shown to have formed half their stellar mass by 11 Gyr ago, whereas the least massive galaxies reached this stage as late as 4 Gyr ago (the well-known effect of ‘galaxy downsizing’). Finally, our metallicity approach allows us to follow the average evolution in gas-phase metallicity for populations of galaxies and extract the evolution of the cosmic metal mass density in stars and in gas, producing results in broad agreement with independent, higher redshift observations of metal densities in the Universe.

scholarly journals Stellar populations of galaxies in the ALHAMBRA survey up to z ∼ 1

2019 ◽  
Vol 631 ◽  
pp. A156 ◽  
Author(s):  
L. A. Díaz-García ◽  
A. J. Cenarro ◽  
C. López-Sanjuan ◽  
I. Ferreras ◽  
M. Cerviño ◽  
...  
Keyword(s):  
Star Formation ◽  
Rest Frame ◽  
Stellar Population ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Stellar Mass ◽  
Spectral Energy ◽  
Population Parameters ◽  
Star Forming ◽  
Set Constraints

Aims. Our aim is to determine the distribution of stellar population parameters (extinction, age, metallicity, and star formation rates) of quiescent galaxies within the rest-frame stellar mass–colour diagrams and UVJ colour–colour diagrams corrected for extinction up to z ∼ 1. These novel diagrams reduce the contamination in samples of quiescent galaxies owing to dust-reddened galaxies, and they provide useful constraints on stellar population parameters only using rest-frame colours and/or stellar mass. Methods. We set constraints on the stellar population parameters of quiescent galaxies combining the ALHAMBRA multi-filter photo-spectra with our fitting code for spectral energy distribution, MUlti-Filter FITting (MUFFIT), making use of composite stellar population models based on two independent sets of simple stellar population (SSP) models. The extinction obtained by MUFFIT allowed us to remove dusty star-forming (DSF) galaxies from the sample of red UVJ galaxies. The distributions of stellar population parameters across these rest-frame diagrams are revealed after the dust correction and are fitted by LOESS, a bi-dimensional and locally weighted regression method, to reduce uncertainty effects. Results. Quiescent galaxy samples defined via classical UVJ diagrams are typically contaminated by a ∼20% fraction of DSF galaxies. A significant part of the galaxies in the green valley are actually obscured star-forming galaxies (∼30–65%). Consequently, the transition of galaxies from the blue cloud to the red sequence, and hence the related mechanisms for quenching, seems to be much more efficient and faster than previously reported. The rest-frame stellar mass–colour and UVJ colour–colour diagrams are useful for constraining the age, metallicity, extinction, and star formation rate of quiescent galaxies by only their redshift, rest-frame colours, and/or stellar mass. Dust correction plays an important role in understanding how quiescent galaxies are distributed in these diagrams and is key to performing a pure selection of quiescent galaxies via intrinsic colours.

scholarly journals A unique distant submillimeter galaxy with an X-ray-obscured radio-luminous active galactic nucleus

2018 ◽  
Vol 619 ◽  
pp. A76 ◽  
Author(s):  
X. W. Shu ◽  
Y. Q. Xue ◽  
D. Z. Liu ◽  
T. Wang ◽  
Y. K. Han ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Star Formation ◽  
Active Galactic Nucleus ◽  
Rest Frame ◽  
Spectral Energy Distribution ◽  
Dust Emission ◽  
Stellar Mass ◽  
Spectral Energy ◽  
X Ray ◽  
Photometric Redshift

Aims. We present a multiwavelength study of an atypical submillimeter galaxy, GH500.30, in the GOODS-North field, with the aim to understand its physical properties of stellar and dust emission, as well as the central active galactic nucleus (AGN) activity. Although it is shown that the source is likely an extremely dusty galaxy at high redshift, its exact position of submillimeter emission is unknown. Methods. We use NOEMA observation at 1.2 mm with subarcsecond resolution to resolve the dust emission, and precisely localize the counterparts at other wavelengths, which allows us to better constrain its stellar and dust spectral energy distribution (SED) as well as redshift. We carry out the new near-infrared (NIR) photometry of GH500.30 observed with HST, and perform panchromatic SED modelling from ultraviolet (UV)/optical to submillimeter. We derive the photometric redshift using both NIR and far-infrared (FIR) SED modeling, and place constraints on the stellar and dust properties such as stellar mass, age, dust attenuation, IR luminosity, and star-formation rate (SFR). The AGN properties are inferred from the X-ray spectral analysis and radio observations, and its contribution to the total IR luminosity is estimated from the broadband SED fittings using MAGPHYS. Results. With the new NOEMA interferometric imaging, we confirm that the source is a unique dusty galaxy. It has no obvious counterpart in the optical and even NIR images observed with HST at λ ≲ 1.4 μm. Photometric-redshift analyses from both stellar and dust SED suggest it to likely be at z ≳ 4, though a lower redshift at z ≳ 3.1 cannot be fully ruled out (at 90% confidence interval). Explaining its unusual optical-to-NIR properties requires an old stellar population (∼0.67 Gyr), coexisting with a very dusty ongoing starburst component. The latter is contributing to the FIR emission, with its rest-frame UV and optical light being largely obscured along our line of sight. If the observed fluxes at the rest-frame optical/NIR wavelengths were mainly contributed by old stars, a total stellar mass of ∼3.5 × 1011 M⊙ would be obtained. An X-ray spectral analysis suggests that this galaxy harbors a heavily obscured AGN with NH = 3.3+2.0−1.7 × 1023 cm−2 and an intrinsic 2–10 keV luminosity of Lx ∼ 2.6 × 1044 erg s−1, which places this object among distant type 2 quasars. The radio emission of the source is extremely bright, which is an order of magnitude higher than the star-formation-powered emission, making it one of the most distant radio-luminous dusty galaxies. Conclusions. The combined characteristics of the galaxy suggest that the source appears to have been caught in a rare but critical transition stage in the evolution of submillimeter galaxies, where we are witnessing the birth of a young AGN and possibly the earliest stage of its jet formation and feedback.

scholarly journals The Relation between Star-Formation Rate and Stellar Mass of Galaxies atz~ 1–4

2016 ◽  
Vol 33 ◽  
Author(s):  
A. Katsianis ◽  
E. Tescari ◽  
J. S. B. Wyithe
Keyword(s):  
Star Formation ◽  
Energy Distribution ◽  
Star Formation Rate ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Stellar Mass ◽  
Numerical Results ◽  
High Mass ◽  
Spectral Energy ◽  
Hydrodynamic Simulations

AbstractThe relation between the star-formation Rate and stellar mass (M⋆) of galaxies represents a fundamental constraint on galaxy formation, and has been studied extensively both in observations and cosmological hydrodynamic simulations. However, the observed amplitude of the star-formation rate—stellar mass relation has not been successfully reproduced in simulations, indicating either that the halo accretion history and baryonic physics are poorly understood/modelled or that observations contain biases. In this paper, we examine the evolution of the SFR −M⋆relation ofz~ 1–4 galaxies and display the inconsistency between observed relations that are obtained using different techniques. We employ cosmological hydrodynamic simulations from various groups which are tuned to reproduce a range of observables and compare these with a range of observed SFR −M⋆relations. We find that numerical results are consistent with observations that use Spectral Energy Distribution techniques to estimate star-formation rates, dust corrections, and stellar masses. On the contrary, simulations are not able to reproduce results that were obtained by combining only UV and IR luminosities (UV+IR). These imply star-formation rates at a fixed stellar mass that are larger almost by a factor of 5 than those of Spectral Energy Distribution measurements forz~ 1.5–4. Forz< 1.5, the results from simulations, Spectral Energy Distribution fitting techniques and IR+UV conversion agree well. We find that surveys that preferably select star-forming galaxies (e.g. by adopting Lyman-break or blue selection) typically predict a larger median/average star-formation rate at a fixed stellar mass especially for high mass objects, with respect to mass selected samples and hydrodynamic simulations. Furthermore, we find remarkable agreement between the numerical results from various authors who have employed different cosmological codes and run simulations with different resolutions. This is interesting for two reasons. (A) simulations can produce realistic populations of galaxies within representative cosmological volumes even at relatively modest resolutions. (B) It is likely that current numerical codes that rely on similar subgrid multiphase interstellar medium models and are tuned to reproduce statistical properties of galaxies, produce similar results for the SFR −M⋆relation by construction, regardless of resolution, box size and, to some extent, the adopted feedback prescriptions.

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 The stellar mass assembly of low-redshift, massive, central galaxies in SDSS and the TNG300 simulation

2020 ◽  
Vol 497 (4) ◽  
pp. 4262-4275
Author(s):  
Thomas M Jackson ◽  
A Pasquali ◽  
C Pacifici ◽  
C Engler ◽  
A Pillepich ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Stellar Mass ◽  
Spectral Energy ◽  
Distribution Fitting ◽  
Stellar Ages ◽  
Mass Assembly ◽  
Galaxy Assembly ◽  
The Times ◽  
Stellar Masses ◽  
Kinetic Mode

ABSTRACT The stellar mass assembly of galaxies can be affected by both secular and environmental processes. In this study, for the first time, we investigate the stellar mass assembly of $\sim 90\, 000$ low-redshift, central galaxies selected from SDSS group catalogues ($M_{\rm Stellar}\gtrsim 10^{9.5}\, \mathrm{M}_{\odot }$, $M_{\rm Halo}\gtrsim 10^{12}\, \mathrm{M}_{\odot }$) as a function of both stellar mass and halo mass. We use estimates of the times at which 10, 50, and 90 per cent of the stellar mass were assembled from photometric spectral energy distribution fitting, allowing a more complete investigation than single stellar ages alone. We consider trends in both stellar mass and halo mass simultaneously, finding dependences of all assembly times on both. We find that galaxies with higher stellar masses (at constant halo mass) have on average older lookback times, similar to previous studies of galaxy assembly. We also find that galaxies at higher halo mass (at constant stellar mass) have younger lookback times, possibly due to a larger reservoir of gas for star formation. An exception to this is a subsample with high stellar-to-halo mass ratios, which are likely massive, field spirals. We compare these observed trends to those predicted by the TNG300 simulation, finding good agreement overall as a function of either stellar mass or halo mass. However, some differences in the assembly times (of up to ∼3 Gyr) appear when considering both stellar mass and halo mass simultaneously, noticeably at intermediate stellar masses (MStellar ∼ 1011 M⊙). These discrepancies are possibly linked to the quenched fraction of galaxies and the kinetic mode active galactic nucleus feedback implemented in TNG300.

scholarly journals Influence of Microlensing on Spectral Anomalies of the Lensed Objects

2011 ◽  
Vol 20 (3) ◽  
Author(s):  
S. Simić ◽  
L. Č. Popović ◽  
P. Jovanović
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Angular Size ◽  
Black Body ◽  
Spectral Energy

AbstractHere we consider the influence of microlensing on the spectrum of a lensed object with the angular size 5 μas accepting that the composite emission of this object originates from three different regions arranged around its center. We assume that the lensed object has three concentric regions with a black-body emission; the temperatures of these regions are 10 000 K, 7500 K and 5000 K. We investigate how the integral spectral energy distribution (SED) of such stratified source changes due to microlensing by a group of solarmass stars. We find that the SED and flux ratios in the photometric B, V and R passbands show considerable changes during a microlens event. This indicates that the flux anomaly observed in some lensed quasars may be caused by microlensing of a stratified object.

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