Characterizing SL2S galaxy groups using the Einstein radius

T. Verdugo; V. Motta; G. Foex; J. E. Forero-Romero; R. P. Munoz; R. Pello; M. Limousin; A. More; R. Cabanac; G. Soucail; J. P. Blakeslee; A. J. Mejia-Narvaez; G. Magris; J. G. Fernandez-Trincado

doi:10.1051/0004-6361/201423696

Characterizing SL2S galaxy groups using the Einstein radius

T. Verdugo, V. Motta, G. Foex, J. E. Forero-Romero, R. P. Munoz, R. Pello, M. Limousin, A. More, R. Cabanac, G. Soucail, J. P. Blakeslee, A. J. Mejia-Narvaez, G. Magris, J. G. Fernandez-Trincado

DARK

6 Citations (Scopus)

Abstract

Aims. We aim to study the reliability of R_A (the distance from the arcs to the center of the lens) as a measure of the Einstein radius in galaxy groups. In addition, we want to analyze the possibility of using R_A as a proxy to characterize some properties of galaxy groups, such as luminosity (L) and richness (N).

Methods. We analyzed the Einstein radius, θ_E, in our sample of Strong Lensing Legacy Survey (SL2S) galaxy groups, and compared it with R_A, using three different approaches: 1) the velocity dispersion obtained from weak lensing assuming a singular isothermal sphere profile (θ_E,I); 2) a strong lensing analytical method (θ_E,II) combined with a velocity dispersion-concentration relation derived from numerical simulations designed to mimic our group sample; and 3) strong lensing modeling (θ_E,III) of eleven groups (with four new models presented in this work) using Hubble Space Telescope (HST) and Canada-France-Hawaii Telescope (CFHT) images. Finally, R_A was analyzed as a function of redshift z to investigate possible correlations with L, N, and the richness-to-luminosity ratio (N/L).

Results. We found a correlation between θ_E and R_A, but with large scatter. We estimate θ_E,I = (2.2 ± 0.9) + (0.7 ± 0.2)R_A, θ_E,II = (0.4 ± 1.5) + (1.1 ± 0.4)R_A, and θ_E,III = (0.4 ± 1.5) + (0.9 ± 0.3)R_A for each method respectively. We found weak evidence of anti-correlation between R_A and z, with Log R_A = (0.58 ± 0.06) − (0.04 ± 0.1)z, suggesting a possible evolution of the Einstein radius with z, as reported previously by other authors. Our results also show that R_A is correlated with L and N (more luminous and richer groups have greater R_A), and a possible correlation between R_A and the N/L ratio.

Conclusions. Our analysis indicates that R_A is correlated with θ_E in our sample, making R_A useful for characterizing properties like L and N (and possibly N/L) in galaxy groups. Additionally, we present evidence suggesting that the Einstein radius evolves with z.

Original language	English
Article number	A65
Journal	Astronomy & Astrophysics
Volume	571
ISSN	0004-6361
DOIs	https://doi.org/10.1051/0004-6361/201423696
Publication status	Published - 1 Nov 2014

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@article{452b5d29ecc644e7b409d451b71268b2,

title = "Characterizing SL2S galaxy groups using the Einstein radius",

abstract = "Aims. We aim to study the reliability of RA (the distance from the arcs to the center of the lens) as a measure of the Einstein radius in galaxy groups. In addition, we want to analyze the possibility of using RA as a proxy to characterize some properties of galaxy groups, such as luminosity (L) and richness (N). Methods. We analyzed the Einstein radius, θE, in our sample of Strong Lensing Legacy Survey (SL2S) galaxy groups, and compared it with RA, using three different approaches: 1) the velocity dispersion obtained from weak lensing assuming a singular isothermal sphere profile (θE,I); 2) a strong lensing analytical method (θE,II) combined with a velocity dispersion-concentration relation derived from numerical simulations designed to mimic our group sample; and 3) strong lensing modeling (θE,III) of eleven groups (with four new models presented in this work) using Hubble Space Telescope (HST) and Canada-France-Hawaii Telescope (CFHT) images. Finally, RA was analyzed as a function of redshift z to investigate possible correlations with L, N, and the richness-to-luminosity ratio (N/L). Results. We found a correlation between θE and RA, but with large scatter. We estimate θE,I = (2.2 ± 0.9) + (0.7 ± 0.2)RA, θE,II = (0.4 ± 1.5) + (1.1 ± 0.4)RA, and θE,III = (0.4 ± 1.5) + (0.9 ± 0.3)RA for each method respectively. We found weak evidence of anti-correlation between RA and z, with Log RA = (0.58 ± 0.06) − (0.04 ± 0.1)z, suggesting a possible evolution of the Einstein radius with z, as reported previously by other authors. Our results also show that RA is correlated with L and N (more luminous and richer groups have greater RA), and a possible correlation between RA and the N/L ratio. Conclusions. Our analysis indicates that RA is correlated with θE in our sample, making RA useful for characterizing properties like L and N (and possibly N/L) in galaxy groups. Additionally, we present evidence suggesting that the Einstein radius evolves with z.",

author = "T. Verdugo and V. Motta and G. Foex and Forero-Romero, {J. E.} and Munoz, {R. P.} and R. Pello and M. Limousin and A. More and R. Cabanac and G. Soucail and Blakeslee, {J. P.} and Mejia-Narvaez, {A. J.} and G. Magris and Fernandez-Trincado, {J. G.}",

year = "2014",

month = nov,

day = "1",

doi = "10.1051/0004-6361/201423696",

language = "English",

volume = "571",

journal = "Astronomy and Astrophysics Supplement Series",

issn = "0004-6361",

publisher = "E D P Sciences",

}

TY - JOUR

T1 - Characterizing SL2S galaxy groups using the Einstein radius

AU - Verdugo, T.

AU - Motta, V.

AU - Foex, G.

AU - Forero-Romero, J. E.

AU - Munoz, R. P.

AU - Pello, R.

AU - Limousin, M.

AU - More, A.

AU - Cabanac, R.

AU - Soucail, G.

AU - Blakeslee, J. P.

AU - Mejia-Narvaez, A. J.

AU - Magris, G.

AU - Fernandez-Trincado, J. G.

PY - 2014/11/1

Y1 - 2014/11/1

N2 - Aims. We aim to study the reliability of RA (the distance from the arcs to the center of the lens) as a measure of the Einstein radius in galaxy groups. In addition, we want to analyze the possibility of using RA as a proxy to characterize some properties of galaxy groups, such as luminosity (L) and richness (N). Methods. We analyzed the Einstein radius, θE, in our sample of Strong Lensing Legacy Survey (SL2S) galaxy groups, and compared it with RA, using three different approaches: 1) the velocity dispersion obtained from weak lensing assuming a singular isothermal sphere profile (θE,I); 2) a strong lensing analytical method (θE,II) combined with a velocity dispersion-concentration relation derived from numerical simulations designed to mimic our group sample; and 3) strong lensing modeling (θE,III) of eleven groups (with four new models presented in this work) using Hubble Space Telescope (HST) and Canada-France-Hawaii Telescope (CFHT) images. Finally, RA was analyzed as a function of redshift z to investigate possible correlations with L, N, and the richness-to-luminosity ratio (N/L). Results. We found a correlation between θE and RA, but with large scatter. We estimate θE,I = (2.2 ± 0.9) + (0.7 ± 0.2)RA, θE,II = (0.4 ± 1.5) + (1.1 ± 0.4)RA, and θE,III = (0.4 ± 1.5) + (0.9 ± 0.3)RA for each method respectively. We found weak evidence of anti-correlation between RA and z, with Log RA = (0.58 ± 0.06) − (0.04 ± 0.1)z, suggesting a possible evolution of the Einstein radius with z, as reported previously by other authors. Our results also show that RA is correlated with L and N (more luminous and richer groups have greater RA), and a possible correlation between RA and the N/L ratio. Conclusions. Our analysis indicates that RA is correlated with θE in our sample, making RA useful for characterizing properties like L and N (and possibly N/L) in galaxy groups. Additionally, we present evidence suggesting that the Einstein radius evolves with z.

AB - Aims. We aim to study the reliability of RA (the distance from the arcs to the center of the lens) as a measure of the Einstein radius in galaxy groups. In addition, we want to analyze the possibility of using RA as a proxy to characterize some properties of galaxy groups, such as luminosity (L) and richness (N). Methods. We analyzed the Einstein radius, θE, in our sample of Strong Lensing Legacy Survey (SL2S) galaxy groups, and compared it with RA, using three different approaches: 1) the velocity dispersion obtained from weak lensing assuming a singular isothermal sphere profile (θE,I); 2) a strong lensing analytical method (θE,II) combined with a velocity dispersion-concentration relation derived from numerical simulations designed to mimic our group sample; and 3) strong lensing modeling (θE,III) of eleven groups (with four new models presented in this work) using Hubble Space Telescope (HST) and Canada-France-Hawaii Telescope (CFHT) images. Finally, RA was analyzed as a function of redshift z to investigate possible correlations with L, N, and the richness-to-luminosity ratio (N/L). Results. We found a correlation between θE and RA, but with large scatter. We estimate θE,I = (2.2 ± 0.9) + (0.7 ± 0.2)RA, θE,II = (0.4 ± 1.5) + (1.1 ± 0.4)RA, and θE,III = (0.4 ± 1.5) + (0.9 ± 0.3)RA for each method respectively. We found weak evidence of anti-correlation between RA and z, with Log RA = (0.58 ± 0.06) − (0.04 ± 0.1)z, suggesting a possible evolution of the Einstein radius with z, as reported previously by other authors. Our results also show that RA is correlated with L and N (more luminous and richer groups have greater RA), and a possible correlation between RA and the N/L ratio. Conclusions. Our analysis indicates that RA is correlated with θE in our sample, making RA useful for characterizing properties like L and N (and possibly N/L) in galaxy groups. Additionally, we present evidence suggesting that the Einstein radius evolves with z.

U2 - 10.1051/0004-6361/201423696

DO - 10.1051/0004-6361/201423696

M3 - Journal article

SN - 0004-6361

VL - 571

JO - Astronomy and Astrophysics Supplement Series

JF - Astronomy and Astrophysics Supplement Series

M1 - A65

ER -