Total Galaxy Magnitudes and Effective Radii from Petrosian Magnitudes and Radii

By Alister W. Graham, S. Driver, V. Petrosian, Christopher J. Conselice, M. Bershady, S. Crawford, T. Goto. 2005

154 citations recorded by the source corpus.

Petrosian magnitudes were designed to help with the difficult task of determining a galaxy's total light. Although these magnitudes [taken here as the flux within 2RP, with the inverted Petrosian index 1/η(RP) = 0.2] can represent most of an object's flux, they do of course miss the light outside the Petrosian aperture (2RP). The size of this flux deficit varies monotonically with the shape of a galaxy's light profile, i.e., its concentration. In the case of a de Vaucouleurs R1/4 profile, the deficit is 0.20 mag; for an R1/8 profile this figure rises to 0.50 mag. Here we provide a simple method for recovering total (Sérsic) magnitudes from Petrosian magnitudes using only the galaxy concentration (R90/R50 or R80/R20) within the Petrosian aperture. The corrections hold to the extent that Sérsic's model provides a good description of a galaxy's luminosity profile. We show how the concentration can also be used to convert Petrosian radii into effective half-light radii, enabling a robust measure of the mean effective surface brightness. Our technique is applied to the Sloan Digital Sky Survey Data Release 2 (SDSS DR2) Petrosian parameters, yielding good agreement with the total magnitudes, effective radii, and mean effective surface brightnesses obtained from the New York University Value-Added Galaxy Catalog Sérsic R1/n fits by Blanton and coworkers. Although the corrective procedure described here is specifically applicable to the SDSS DR2 and DR3, it is generally applicable to all imaging data where any Petrosian index and concentration can be constructed.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/31af5874a349936e1efdb232ffaf1fea010e3187

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Citations in the corpus

Curvature in the scaling relations of early-type galaxies (2008, background): “Graham et al. (2005) provide a prescription for transforming from Petrosian to Sersic quantities.”
Structural and Star-forming Relations since z ∼ 3: Connecting Compact Star-forming and Quiescent Galaxies (2015, methodology): “By integrating Equation 4 we obtain: logΣ1kpc − logM⋆ = − logπ − log γ(2n, bnr −1/n e ) (5) where γ is the incomplete gamma function, which depends on n and re (see e.g., Graham et al. 2005).”
The SLUGGS Survey: kinematics for over 2500 globular clusters in 12 early-type galaxies (2012, methodology): “…1963) similar to that commonly carried out for galaxy surface brightness profiles, but in practice we fit a variation of the Sérsic profile from Graham et al. (2005) in order to quantify the background level: N (r) = Ne exp ( −bn [( R Reff )1/n − 1 ]) + bg , (1) where bn = 1.9992n − 0.3271,…”
MegaMorph - multiwavelength measurement of galaxy structure: complete Sersic profile information from modern surveys (2012, methodology): “Further refinements include applying convolutions to match the point spread functions (PSFs) of the images (e.g., Hill et al. 2011), and applying a minimal correction by estimating the flux that would be missed if the galaxy were a point source (e.g., White et al. 2005; Graham et al. 2005).”
REPRODUCING THE STELLAR MASS/HALO MASS RELATION IN SIMULATED ΛCDM GALAXIES: THEORY VERSUS OBSERVATIONAL ESTIMATES (2012, background): “…often measure individual galaxy magnitudes within an aperture based on a surface brightness cutoff, the mass of the stellar component could be systematically underestimated by at least 20% (Graham et al. 2005; Shimasaku et al. 2001) if part of it is old (hence faint) and/or low surface brightness.”
GEMS: Galaxy Fitting Catalogs and Testing Parametric Galaxy Fitting Codes: GALFIT and GIM2D (2007, background): “…disks (n = 1) and the R1/4-law (de Vaucouleurs law) profiles typical of luminous early-type galaxy (n = 4) (e.g., deVaucouleurs 1948; Freeman 1970); fitting with this profile has been explored in detail in a number of works (e.g., Simard 1998, 2002; Graham et al. 2005; Trujillo et al. 2001).”
Empirical Models for Dark Matter Halos. II. Inner Profile Slopes, Dynamical Profiles, and ρ/σ3 (2006, methodology): “Finally, we note that the use of a Petrosianstyle radius (Petrosian 1976; Graham et al. 2005), such that the mean density inside of some radius divided by the density at that radius equals some constant value, is not suitable in the case of structural homology.”
Inclination- and dust-corrected galaxy parameters: bulge-to-disc ratios and size–luminosity relations (2008, methodology): “We can now use the relation R50 ≈ [1− 6.0× 10 −6(R90/R50) 8.92]Re from Graham et al. (2005) to quantify the difference between the Petrosian half light radii R50 (used by Shen et al.) and the effective half light radii Re (used in Figure 11a).”
NEWLY QUENCHED GALAXIES AS THE CAUSE FOR THE APPARENT EVOLUTION IN AVERAGE SIZE OF THE POPULATION (2013, methodology): “…size measurements based on aperture fluxes are wellknown to prone to systematic biases in the small-size and low surface brightness regimes (e.g. Graham et al. 2005; Cameron & Driver 2007), we nevertheless favor this technique over a profile-fitting approach (cf. Sargent et al. 2007, Mancini et…”
The massive end of the luminosity and stellar mass functions: Dependence on the fit to the light profile (2013, methodology): “…with respect to our PyMorph magnitudes, our results suggest that they should only be used after applying the sorts of corrections advocated by Graham et al. (2005) which partially account for the fact that Petrosian magni- c© 0000 RAS, MNRAS 000, 000–000 tudes underestimate the total light…”
The Evolution of Galaxy Structure Over Cosmic Time (2014, methodology): “The concentration index however has to be measured very carefully, as different regions and radii used can produce very different values that systematically do not reproduce well when observed under degraded conditions (e.g., Graham et al. 2001; Graham et al. 2005).”
Galaxy and Mass Assembly (GAMA): ugriz galaxy luminosity functions (2011, methodology): “We make no attempt here to correct for intrinsic dust extinction within each galaxy, as was done by Driver et al. (2007), nor to extrapolate the Petrosian magnitudes to total, as done, for example, by Graham et al. (2005) and Hill et al. (2011).”
Galactic accretion and the outer structure of galaxies in the CDM model (2013, background): “…sizes derived from SDSS photometric measurements miss a substantial fraction of light in the outer regions of massive galaxies with high Sèrsic index (Graham et al. 2005; Bernardi et al. 2007; Lauer et al. 2007; Blanton et al. 2011; Bernardi et al. 2012; Meert et al. 2012; Mosleh, Williams &…”