scholarly journals Models of stellar population at high redshift, as constrainedby PN yields and luminosity function

2015 ◽  
Vol 11 (A29B) ◽  
pp. 26-32
Author(s):  
C. Maraston
Keyword(s):  
Luminosity Function ◽  
Stellar Population ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Population Models ◽  
Asymptotic Giant Branch ◽  
Theoretical Modelling ◽  
Spectral Energy ◽  
Evolutionary Stage ◽  
Intermediate Mass Stars

AbstractThe stellar phase of Thermally-Pulsating Asymptotic giant branch is the last major evolutionary stage of intermediate-mass stars which afterwards evolve into planetary nebulae. The TP-AGB phase is affected by mass-loss and instabilities which notoriously make its theoretical modelling uncertain. This review focuses on the effects such modelling has on stellar population models for galaxies, with particular focus on the high-z Universe where galaxies are young and contain a large number of short-living TP-AGB stars. I shall present the models, discuss how different prescriptions for the treatment of the TP-AGB affect the theoretical integrated spectral energy distribution and how these compare to galaxy data, and discuss implications for the PN nebulae luminosity function stemming from the various assumptions. Finally I shall discuss the inclusion of hot evolved stars on stellar population models and how they compare to data for old galaxies at our present time.

scholarly journals Models of stellar population at high redshift, as constrained by PN yields and luminosity function

2015 ◽  
Vol 11 (A29B) ◽  
Author(s):  
C. Maraston
Keyword(s):  
Luminosity Function ◽  
Stellar Population ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Population Models ◽  
Asymptotic Giant Branch ◽  
Theoretical Modelling ◽  
Spectral Energy ◽  
Evolutionary Stage ◽  
Intermediate Mass Stars

AbstractThe stellar phase of Thermally-Pulsating Asymptotic giant branch is the last major evolutionary stage of intermediate-mass stars which afterwards evolve into planetary nebulae. The TP-AGB phase is affected by mass-loss and instabilities which notoriously make its theoretical modelling uncertain. This review focuses on the effects such modelling has on stellar population models for galaxies, with particular focus on the high-z Universe where galaxies are young and contain a large number of short-living TP-AGB stars. I shall present the models, discuss how different prescriptions for the treatment of the TP-AGB affect the theoretical integrated spectral energy distribution and how these compare to galaxy data, and discuss implications for the PN nebulae luminosity function stemming from the various assumptions. Finally I shall discuss the inclusion of hot evolved stars on stellar population models and how they compare to data for old galaxies at our present time.

scholarly journals Late stages of stellar evolution in population models

2014 ◽  
Vol 10 (S311) ◽  
pp. 57-62
Author(s):  
Claudia Maraston
Keyword(s):  
Stellar Population ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Population Models ◽  
Asymptotic Giant Branch ◽  
Spectral Energy ◽  
Massive Galaxies ◽  
Distant Galaxies ◽  
Recent Developments ◽  
Treat All

AbstractMy contribution to Roger's celebration symposium focuses on the treatment of late stellar evolutionary phases in stellar population models, reviewing the state of art and discussing some very recent developments, ranging from local stellar clusters up to distant galaxies at high redshift. I shall focus in particular on the Thermally Pulsating Asymptotic Giant Branch, about which a vivid discussion has been ongoing since a few years. I shall present renewed evidence in favour of a sizable contribution from this phase for matching the observed spectral energy distribution of distant massive galaxies. I shall also discuss the possible reasons why such a conclusion has been controversial in the recent literature. Stellar population models are the magic tool to shape the physics of galaxies out of their observed light, and enter virtually all papers presented at this symposium. In a collective effort to properly treat all relevant aspects of the modelling, we split the discussion into six contributions given by experts in the field, as our present to Roger and his outstanding career.

scholarly journals Stellar Population Models

2012 ◽  
Vol 8 (S295) ◽  
pp. 272-281 ◽  
Author(s):  
Claudia Maraston
Keyword(s):  
Galaxy Formation ◽  
Stellar Population ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Cosmic Time ◽  
Mass Function ◽  
Initial Mass Function ◽  
Asymptotic Giant Branch ◽  
Spectral Energy ◽  
Massive Galaxies

AbstractModelling stellar populations in galaxies is a key approach to gain knowledge on the still elusive process of galaxy formation as a function of cosmic time. In this review, after a summary of the state-of-art, I discuss three aspects of the modelling, that are particularly relevant to massive galaxies, the focus of this symposium, at low and high-redshift. These are the treatment of the Thermally-Pulsating Asymptotic Giant Branch phase, evidences of an unusual Initial Mass Function, and the effect of modern stellar libraries on the model spectral energy distribution.

Populations of candidate black holes at redshift 7 or above

2006 ◽  
Vol 2 (14) ◽  
pp. 258-258
Author(s):  
Anton M. Koekemoer
Keyword(s):  
Black Holes ◽  
Luminosity Function ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Galactic Nuclei ◽  
Spectral Energy ◽  
Distribution Modelling ◽  
Optical Wavelengths ◽  
The Universe ◽  
Selection Of

AbstractI will describe recent results on constructing samples of candidate active galactic nuclei (AGN) at or beyond redshift 7, probing several orders of magnitude fainter than the top end of the quasar luminosity function at redshift 6. These advances have been made possible by the advent of deep, wide multi-waveband surveys that enable the selection of samples of sources that are detected at radio or X-ray wavelengths but completely undetected at optical wavelengths to very deep limits. A variety of multi-band selection criteria are used to identify the high-redshift candidates and eliminate lower-redshift interlopers by means of extensive spectral energy distribution modelling. The resulting constraints on the numbers of high-redshift AGN at or above redshift 7 are used to examine the evolution of the AGN luminosity function at high redshift, and help understand the properties of the first supermassive black holes in the universe.

scholarly journals Red supergiant stars in the Large Magellanic Cloud

2018 ◽  
Vol 616 ◽  
pp. A175 ◽  
Author(s):  
Ming Yang ◽  
Alceste Z. Bonanos ◽  
Bi-Wei Jiang ◽  
Jian Gao ◽  
Meng-Yao Xue ◽  
...  
Keyword(s):  
Time Series ◽  
Time Series Data ◽  
Spectral Energy Distribution ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Asymptotic Giant Branch ◽  
Series Data ◽  
Spectral Energy ◽  
Evolutionary Stage ◽  
Evolutionary Models

The characteristics of infrared properties and mid-infrared (MIR) variability of red supergiant (RSG) stars in the Large Magellanic Cloud (LMC) are analyzed based on 12 bands of near-infrared (NIR) to MIR co-added data from 2MASS, Spitzer and WISE, and ∼6.6 yr of MIR time-series data collected by the ALLWISE and NEOWISE-R projects. 773 RSGs candidates were compiled from the literature and verified by using the color-magnitude diagram (CMD), spectral energy distribution (SED) and MIR variability. About 15% of valid targets in the IRAC1–IRAC2/IRAC2–IRAC3 diagram may show polycyclic aromatic hydrocarbon (PAH) emission. We show that arbitrary dereddening Q parameters related to the IRAC4, S9W, WISE3, WISE4, and MIPS24 bands could be constructed based on a precise measurement of MIR interstellar extinction law. Several peculiar outliers in our sample are discussed, in which one outlier might be a RSG right before the explosion or an extreme asymptotic giant branch (AGB) star in the very late evolutionary stage based on the MIR spectrum and photometry. There are 744 identified RSGs in the final sample having both the WISE1- and WISE2-band time-series data. The results show that the MIR variability is increasing along with the increasing of brightness. There is a relatively tight correlation between the MIR variability, mass loss rate (MLR; in terms of KS–WISE3 color), and the warm dust or continuum (in terms of WISE4 magnitude/flux), where the MIR variability is evident for the targets with KS–WISE3 > 1.0 mag and WISE4 < 6.5 mag, while the rest of the targets show much smaller MIR variability. The MIR variability is also correlated with the MLR for which targets with larger variability also show larger MLR with an approximate upper limit of −6.1 M⊙ yr−1. Both the variability and the luminosity may be important for the MLR since the WISE4-band flux is increasing exponentially along with the degeneracy of luminosity and variability. The identified RSG sample has been compared with the theoretical evolutionary models and shown that the discrepancy between observation and evolutionary models can be mitigated by considering both variability and extinction.

scholarly journals Are extreme asymptotic giant branch stars post-common envelope binaries?

2021 ◽  
Vol 502 (1) ◽  
pp. L35-L39
Author(s):  
F Dell’Agli ◽  
E Marini ◽  
F D’Antona ◽  
P Ventura ◽  
M A T Groenewegen ◽  
...  
Keyword(s):  
Large Fraction ◽  
Carbon Star ◽  
Large Magellanic Cloud ◽  
Asymptotic Giant Branch ◽  
Theoretical Modelling ◽  
Binary Interaction ◽  
Spectral Energy ◽  
Small Subset ◽  
Stellar Radius ◽  
Common Envelope

ABSTRACT Modelling dust formation in single stars evolving through the carbon-star stage of the asymptotic giant branch (AGB) reproduces well the mid-infrared colours and magnitudes of most of the C-rich sources in the Large Magellanic Cloud (LMC), apart from a small subset of extremely red objects (EROs). An analysis of the spectral energy distributions of EROs suggests the presence of large quantities of dust, which demand gas densities in the outflow significantly higher than expected from theoretical modelling. We propose that binary interaction mechanisms that involve common envelope (CE) evolution could be a possible explanation for these peculiar stars; the CE phase is favoured by the rapid growth of the stellar radius occurring after C/O overcomes unity. Our modelling of the dust provides results consistent with the observations for mass-loss rates $\dot{M} \sim 5\times 10^{-4}\,{\rm M}_{\odot }$ yr−1, a lower limit to the rapid loss of the envelope experienced in the CE phase. We propose that EROs could possibly hide binaries with orbital periods of about days and are likely to be responsible for a large fraction of the dust production rate in galaxies.

scholarly journals Towards a census of high-redshift dusty galaxies with Herschel

2018 ◽  
Vol 614 ◽  
pp. A33 ◽  
Author(s):  
D. Donevski ◽  
V. Buat ◽  
F. Boone ◽  
C. Pappalardo ◽  
M. Bethermin ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Far Infrared ◽  
Virgo Cluster ◽  
Spectral Energy ◽  
Distribution Fitting ◽  
Redshift Distribution ◽  
Star Forming

Context. Over the last decade a large number of dusty star-forming galaxies has been discovered up to redshift z = 2 − 3 and recent studies have attempted to push the highly confused Herschel SPIRE surveys beyond that distance. To search for z ≥ 4 galaxies they often consider the sources with fluxes rising from 250 μm to 500 μm (so-called “500 μm-risers”). Herschel surveys offer a unique opportunity to efficiently select a large number of these rare objects, and thus gain insight into the prodigious star-forming activity that takes place in the very distant Universe. Aims. We aim to implement a novel method to obtain a statistical sample of 500 μm-risers and fully evaluate our selection inspecting different models of galaxy evolution. Methods. We consider one of the largest and deepest Herschel surveys, the Herschel Virgo Cluster Survey. We develop a novel selection algorithm which links the source extraction and spectral energy distribution fitting. To fully quantify selection biases we make end-to-end simulations including clustering and lensing. Results. We select 133 500 μm-risers over 55 deg2, imposing the criteria: S500 > S350 > S250, S250 > 13.2 mJy and S500 > 30 mJy. Differential number counts are in fairly good agreement with models, displaying a better match than other existing samples. The estimated fraction of strongly lensed sources is 24+6-5% based on models. Conclusions. We present the faintest sample of 500 μm-risers down to S250 = 13.2 mJy. We show that noise and strong lensing have an important impact on measured counts and redshift distribution of selected sources. We estimate the flux-corrected star formation rate density at 4 < z < 5 with the 500 μm-risers and find it to be close to the total value measured in far-infrared. This indicates that colour selection is not a limiting effect to search for the most massive, dusty z > 4 sources.

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 The Stellar Mass of M31 as inferred by the Andromeda Optical & Infrared Disk Survey

2014 ◽  
Vol 10 (S311) ◽  
pp. 82-85 ◽  
Author(s):  
Jonathan Sick ◽  
Stephane Courteau ◽  
Jean-Charles Cuillandre ◽  
Julianne Dalcanton ◽  
Roelof de Jong ◽  
...  
Keyword(s):  
Stellar Population ◽  
Spectral Energy Distribution ◽  
Major Axis ◽  
Stellar Mass ◽  
Spectral Energy ◽  
Population Synthesis ◽  
Disk Formation ◽  
Infrared Spectral ◽  
Inside Out ◽  
Additional Constraints

AbstractOur proximity and external vantage point make M31 an ideal testbed for understanding the structure of spiral galaxies. The Andromeda Optical and Infrared Disk Survey (ANDROIDS) has mapped M31's bulge and disk out to R=40 kpc in ugriJKs bands with CFHT using a careful sky calibration. We use Bayesian modelling of the optical-infrared spectral energy distribution (SED) to estimate profiles of M31's stellar populations and mass along the major axis. This analysis provides evidence for inside-out disk formation and a declining metallicity gradient. M31's i-band mass-to-light ratio (M/Li*) decreases from 0.5 dex in the bulge to ~ 0.2 dex at 40 kpc. The best-constrained stellar population models use the full ugriJKs SED but are also consistent with optical-only fits. Therefore, while NIR data can be successfully modelled with modern stellar population synthesis, NIR data do not provide additional constraints in this application. Fits to the gi-SED alone yield M/Li* that are systematically lower than the full SED fit by 0.1 dex. This is still smaller than the 0.3 dex scatter amongst different relations for M/Li via g – i colour found in the literature. We advocate a stellar mass of M*(30 kpc) = 10.3+2.3-1.7 × 1010 M⊙ for the M31 bulge and disk.

scholarly journals The star formation properties of the observed and simulated AGN Universe: BAT versus EAGLE

2020 ◽  
Vol 498 (2) ◽  
pp. 2323-2338
Author(s):  
Thomas M Jackson ◽  
D J Rosario ◽  
D M Alexander ◽  
J Scholtz ◽  
Stuart McAlpine ◽  
...  
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Host Galaxy ◽  
Spectral Energy ◽  
Host Galaxies ◽  
X Ray ◽  
Two Samples ◽  
Stellar Masses

ABSTRACT In this paper, we present data from 72 low-redshift, hard X-ray selected active galactic nucleus (AGN) taken from the Swift–BAT 58 month catalogue. We utilize spectral energy distribution fitting to the optical to infrared photometry in order to estimate host galaxy properties. We compare this observational sample to a volume- and flux-matched sample of AGN from the Evolution and Assembly of GaLaxies and their Environments (EAGLE) hydrodynamical simulations in order to verify how accurately the simulations can reproduce observed AGN host galaxy properties. After correcting for the known +0.2 dex offset in the SFRs between EAGLE and previous observations, we find agreement in the star formation rate (SFR) and X-ray luminosity distributions; however, we find that the stellar masses in EAGLE are 0.2–0.4 dex greater than the observational sample, which consequently leads to lower specific star formation rates (sSFRs). We compare these results to our previous study at high redshift, finding agreement in both the observations and simulations, whereby the widths of sSFR distributions are similar (∼0.4–0.6 dex) and the median of the SFR distributions lie below the star-forming main sequence by ∼0.3–0.5 dex across all samples. We also use EAGLE to select a sample of AGN host galaxies at high and low redshift and follow their characteristic evolution from z = 8 to z = 0. We find similar behaviour between these two samples, whereby star formation is quenched when the black hole goes through its phase of most rapid growth. Utilizing EAGLE we find that 23 per cent of AGN selected at z ∼ 0 are also AGN at high redshift, and that their host galaxies are among the most massive objects in the simulation. Overall, we find EAGLE reproduces the observations well, with some minor inconsistencies (∼0.2 dex in stellar masses and ∼0.4 dex in sSFRs).

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