scholarly journals Surface brightness fluctuation spectra to constrain stellar population properties

2020 ◽  
Vol 493 (4) ◽  
pp. 5131-5152
Author(s):  
A Vazdekis ◽  
M Cerviño ◽  
M Montes ◽  
I Martín-Navarro ◽  
M A Beasley
Keyword(s):  
Galaxy Formation ◽  
Surface Brightness ◽  
Stellar Population ◽  
Near Infrared ◽  
Order Approximation ◽  
Mass Function ◽  
Mass Fractions ◽  
Brightness Fluctuation ◽  
First Order Approximation ◽  
High Degree

ABSTRACT We present a new set of surface brightness fluctuation (SBF) spectra computed with the E-MILES stellar population synthesis models. The model SBF spectra cover the range λλ1680–50 000 at moderately high resolution, all based on extensive empirical stellar libraries. The models span the metallicity range $-2.3\le \mbox{$\mbox{[M/H]}$}\le +0.26$ for a suite of intial mass function types with varying slopes. These predictions can complement and aid fluctuation magnitude studies, permitting a first-order approximation by applying filter responses to the SBF spectra to obtain spectroscopic SBF magnitudes. We provide a recipe for obtaining the latter and discuss their uncertainties and limitations. We compare our spectroscopic SBF magnitudes to photometric data of a sample of early-type galaxies. We also show that the SBF spectra can be very useful for constraining relevant stellar population parameters. We find small (<5 per cent) mass fractions of extremely metal-poor components ($\mbox{$\mbox{[M/H]}$}\lt -1$) on the top of the dominant, old, and metal-rich stellar population. These results put stringent constraints on the early stages of galaxy formation in massive elliptical galaxies. This is remarkable given the high degree of degeneracy of the standard spectral analysis to such metal-poor stellar populations in the visible and in the near-infrared. The new SBF models show great potential for exploiting ongoing surveys, particularly those based on narrow-band filters.

scholarly journals Fingerprints of stellar populations in the near-infrared: an optimized set of spectral indices in the JHK bands 0

2021 ◽  
Vol 504 (2) ◽  
pp. 2190-2223
Author(s):  
Elham Eftekhari ◽  
Alexandre Vazdekis ◽  
Francesco La Barbera
Keyword(s):  
Galaxy Formation ◽  
Spectral Range ◽  
Stellar Population ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Mass Function ◽  
Initial Mass Function ◽  
Elemental Abundance ◽  
Spectral Indices ◽  
Diagnostic Features

ABSTRACT Stellar population studies provide unique clues to constrain galaxy formation models. So far, detailed studies based on absorption line strengths have mainly focused on the optical spectral range although many diagnostic features are present in other spectral windows. In particular, the near-infrared (NIR) can provide a wealth of information about stars, such as evolved giants, that have less evident optical signatures. Due to significant advances in NIR instrumentation and extension of spectral libraries and stellar population synthesis (SPS) models to this domain, it is now possible to perform in-depth studies of spectral features in the NIR to a high level of precision. In this work, taking advantage of state-of-the-art SPS models covering the NIR spectral range, we introduce a new set of NIR indices constructed to be maximally sensitive to the main stellar population parameters, namely age, metallicity, and initial mass function (IMF). We fully characterize the new indices against these parameters as well as their sensitivity to individual elemental abundance variations, velocity dispersion broadening, wavelength shifts, signal-to-noise ratio, and flux calibration. We also present, for the first time, a method to ensure that the analysis of spectral indices is not affected by sky contamination, which is a major challenge when dealing with NIR spectroscopy. Moreover, we discuss two main applications: (i) the ability of some NIR spectral indices to constrain the shape of the low-mass IMF and (ii) current issues in the analysis of NIR spectral indices for future developments of SPS modelling.

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.

scholarly journals Hα and FUV luminosities from a stochastically formed stellar population

2011 ◽  
Vol 7 (S284) ◽  
pp. 53-55
Author(s):  
Nidia Lugo Lopez L. ◽  
Gladis Magris C. ◽  
Antonio Parravano
Keyword(s):  
Power Law ◽  
Surface Brightness ◽  
Stellar Population ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

AbstractIt has been observed that the ratio of Hα to FUV luminosity (LHα/LFUV) is lower in low surface brightness galaxies. This behaviour has been attributed to systematic variations of the upper mass end and/or the slope of the Initial Mass Function (IMF) Meurer et al. (2009) and Lee et al. (2009)). However these hypotheses do not explain the observed scatter in luminosity ratio (LHα/LFUV). We present a model for the total LHα and LFUV luminosity arising from a randomly populated IMF following the Salpeter power law and the clustering law of Oey & Clarke (2007).

scholarly journals Near-Infrared Spectroscopy of NGC 253: Starburst and Surroundings

1996 ◽  
Vol 171 ◽  
pp. 407-407 ◽  
Author(s):  
D. Lutz ◽  
F. Prada
Keyword(s):  
Stellar Population ◽  
Near Infrared ◽  
Velocity Dispersion ◽  
Mass Function ◽  
Infrared Emission ◽  
Initial Mass Function ◽  
Emission Lines ◽  
Lower Mass ◽  
Dynamical Mass ◽  
Near Infrared Emission

Near-infrared longslit spectra of NGC 253 obtained with IRSPEC at the ESO NTT are presented. By analysis of the 12CO 2.29μm bandhead we find that the stellar population in the central starburst region (r ∼ 150 pc) rotates more slowly than the gas, but has a velocity dispersion of 128 km/s, about twice the value found for emission lines from the gas in this region. This implies an about five times higher dynamical mass than previously derived (Rieke et al. 1980), removing the need to invoke a lower mass cutoff in the starburst initial mass function. The peak of near-infrared emission is displaced from the dynamical center.

scholarly journals New near-infrared surface brightness fluctuation models

2005 ◽  
Vol 362 (4) ◽  
pp. 1208-1218 ◽  
Author(s):  
M. Mouhcine ◽  
R. A. González ◽  
M. C. Liu
Keyword(s):  
Surface Brightness ◽  
Near Infrared ◽  
Brightness Fluctuation

scholarly journals Near-infrared surface brightness fluctuation measurements with the Hubble Space Telescope's WFC3/IR channel

2012 ◽  
Vol 8 (S289) ◽  
pp. 371-374
Author(s):  
Hyejeon Cho ◽  
Joseph B. Jensen ◽  
John P. Blakeslee ◽  
Brigham S. French ◽  
Hyun-chul Lee ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Near Infrared ◽  
Hubble Space Telescope ◽  
Wide Field ◽  
Population Synthesis ◽  
Early Type ◽  
Distance Method ◽  
Brightness Fluctuation ◽  
Advanced Camera For Surveys ◽  
Fornax Cluster

AbstractThe surface brightness fluctuation (SBF) method at near-infrared (NIR) wavelengths is a powerful tool for estimating distances to unresolved stellar systems with high precision. The IR channel of the Wide Field Camera 3 (WFC3), installed on board the Hubble Space Telescope (HST) in 2009, has a greater sensitivity and a wider field of view than the previous generation of HST IR instruments, making it much more efficient for measuring distances to early-type galaxies in the Local Volume. To take full advantage of its capabilities, we need to empirically calibrate the SBF distance method for WFC3's NIR passbands. We present the SBF measurements for the WFC3/IR F160W bandpass filter using observations of 16 early-type galaxies in the Fornax and Virgo Clusters. These have been combined with existing (g475–z850) color measurements from the Advanced Camera for Surveys Virgo and Fornax Cluster Surveys to derive a space-based H160-band SBF relation as a function of color. We have also compared the absolute SBF magnitudes to those predicted by evolutionary population synthesis models in order to study stellar population properties in the target galaxies.

scholarly journals New Optical and Near-Infrared Surface Brightness Fluctuation Models. II. Young and Intermediate-Age Stellar Populations

2005 ◽  
Vol 130 (6) ◽  
pp. 2625-2646 ◽  
Author(s):  
G. Raimondo ◽  
E. Brocato ◽  
M. Cantiello ◽  
M. Capaccioli
Keyword(s):  
Surface Brightness ◽  
Near Infrared ◽  
Stellar Populations ◽  
Brightness Fluctuation

scholarly journals Calibration of Surface Brightness Fluctuations for Dwarf Galaxies in the Hyper Suprime-Cam gi Filter System

2021 ◽  
Vol 923 (2) ◽  
pp. 152
Author(s):  
Yoo Jung Kim ◽  
Myung Gyoon Lee
Keyword(s):  
Surface Brightness ◽  
Stellar Population ◽  
Dwarf Galaxies ◽  
Imaging Data ◽  
Standard Candle ◽  
Surface Brightness Fluctuations ◽  
Brightness Fluctuation ◽  
Linear Fit ◽  
Red Giant ◽  
Red Galaxies

Abstract Surface brightness fluctuation (SBF) magnitudes are a powerful standard candle to measure distances to semiresolved galaxies in the local universe, a majority of which are dwarf galaxies that often have bluer colors than bright early-type galaxies. We present an empirical i-band SBF calibration in a blue regime, 0.2 ≲ (g − i)0 ≲ 0.8 in the Hyper Suprime-Cam (HSC) magnitude system. We measure SBF magnitudes for 12 nearby dwarf galaxies of various morphological types with archival HSC imaging data, and use their tip of the red giant branch distances to derive fluctuation–color relations. In order to subtract contributions of fluctuations due to young stellar populations, we use five different g-band magnitude masking thresholds, M g,thres = −3.5, −4.0, −4.5, −5.0, and −5.5 mag. We find that the rms scatter of the linear fit to the relation is the smallest (rms = 0.16 mag) in the case of M g,thres = −4.0 mag, M ¯ i = (−2.65 ± 0.13) + (1.28 ± 0.24) × (g − i)0. This scatter is much smaller than those in the previous studies (rms = 0.26 mag), and is closer to the value for bright red galaxies (rms = 0.12 mag). This calibration is consistent with predictions from metal-poor simple stellar population models.

scholarly journals Securing the Faint End of the Galaxy Luminosity Function

2004 ◽  
Vol 21 (4) ◽  
pp. 356-359 ◽  
Author(s):  
Helmut Jerjen ◽  
Brent Tully ◽  
Neil Trentham
Keyword(s):  
Surface Brightness ◽  
Luminosity Function ◽  
Dwarf Galaxy ◽  
Full Range ◽  
Mass Function ◽  
Wide Field ◽  
Distance Information ◽  
The Galaxy ◽  
Brightness Fluctuation ◽  
Galaxy Luminosity Function

AbstractThe history of the formation of galaxies must leave an imprint in the properties of the mass function of collapsed objects and in its observational manifestation, the galaxy luminosity function. At present the faint end of the luminosity function is poorly known. Accurate knowledge of the luminosity function over the full range of galaxy clustering scales would provide serious constraints on both initial cosmological conditions and modulating astrophysical processes.Wide field imaging surveys with large ground-based telescopes now provide the capability to identify dwarf galaxy candidates to very faint levels (μR ≈ 26 mag arcsec–2), too low in surface brightness for spectroscopy (measuring redshifts) even with telescopes like Keck. Other means have to be explored to get distance information for these candidates in order to separate cluster members from back/foreground systems beyond doubt. On the quest to establish the properties (slope and possible turning point) of the the faint end of the galaxy luminosity function we are employing the surface brightness fluctuation (SBF) method to determine adequate distances, potentially resulting in the best definition ever of the luminosity function to MR ≈ –11 in the cluster and group environments.

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