VLT and ACS observations of RDCS J1252.9-2927

Dynamical structure and galaxy populations in a massive cluster at z = 1.237

R. Demarco, P. Rosati, C. Lidman, M. Girardi, M. Nonino, A. Rettura, V. Strazzullo, A. Van Der Wel, H. C. Ford, V. Mainieri, B. P. Holden, S. A. Stanford, J. P. Blakeslee, R. Gobat, M. Postman, P. Tozzi, R. A. Overzier, A. W. Zirm, N. Benítez, N. L. Homeier & 9 others G. D. Illingworth, L. Infante, Myung Kook Jee, S. Mei, F. Menanteau, V. Motta, W. Zheng, M. Clampin, G. Hartig

Research output: Contribution to journalArticle

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Abstract

We present results from an extensive spectroscopic survey, carried out with VLT FORS, and from an extensive multiwavelength imaging data set from the HST Advanced Camera for Surveys and ground-based facilities, of the cluster of galaxies RDCS J1252.9-2927. We have spectroscopically confirmed 38 cluster members in the redshift range 1.22 < z < 1.25. A cluster median redshift of z = 1.237 and a rest-frame velocity dispersion of 747-84 -74 km s-1 are obtained. Using the 38 confirmed redshifts, we were able to resolve, for the first time at z > 1, kinematic structure The velocity distribution, which is not Gaussian at the 95% confidence level, is consistent with two groups that are also responsible for the projected east-west elongation of the cluster. The groups are composed of 26 and 12 galaxies with velocity dispersions of 486-85+47 and 426-105+57km s-1, respectively. The elongation is also seen in the intracluster gas and the dark matter distribution. This leads us to conclude that RDCS J1252.9-2927 has not yet reached a final virial state. We extend the analysis of the color-magnitude diagram of spectroscopic members to more than 1 Mpc from the cluster center. The scatter and slope of non-[O II]-emitting cluster members in the near-IR red sequence is similar to that seen in clusters at lower redshift. Furthermore, most of the galaxies with luminosities greater than ∼Ks*+1.5 do not show any [O n], indicating that these more luminous, redder galaxies have stopped forming stars earlier than the fainter, bluer galaxies. Our observations provide detailed dynamical and spectrophotometric information on galaxies in this exceptional high-redshift cluster, delivering an in-depth view of structure formation at this epoch only 5 Gyr after the big bang.

Original languageEnglish
Pages (from-to)164-182
Number of pages19
JournalAstrophysical Journal
Volume663
Issue number1 I
DOIs
Publication statusPublished - 2007 Jul 1

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galaxies
kinematics
diagram
elongation
gas
early stars
color-magnitude diagram
distribution
confidence
dark matter
velocity distribution
cameras
luminosity
time measurement
slopes
analysis
gases

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Demarco, R., Rosati, P., Lidman, C., Girardi, M., Nonino, M., Rettura, A., ... Hartig, G. (2007). VLT and ACS observations of RDCS J1252.9-2927: Dynamical structure and galaxy populations in a massive cluster at z = 1.237. Astrophysical Journal, 663(1 I), 164-182. https://doi.org/10.1086/518117
Demarco, R. ; Rosati, P. ; Lidman, C. ; Girardi, M. ; Nonino, M. ; Rettura, A. ; Strazzullo, V. ; Van Der Wel, A. ; Ford, H. C. ; Mainieri, V. ; Holden, B. P. ; Stanford, S. A. ; Blakeslee, J. P. ; Gobat, R. ; Postman, M. ; Tozzi, P. ; Overzier, R. A. ; Zirm, A. W. ; Benítez, N. ; Homeier, N. L. ; Illingworth, G. D. ; Infante, L. ; Jee, Myung Kook ; Mei, S. ; Menanteau, F. ; Motta, V. ; Zheng, W. ; Clampin, M. ; Hartig, G. / VLT and ACS observations of RDCS J1252.9-2927 : Dynamical structure and galaxy populations in a massive cluster at z = 1.237. In: Astrophysical Journal. 2007 ; Vol. 663, No. 1 I. pp. 164-182.
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abstract = "We present results from an extensive spectroscopic survey, carried out with VLT FORS, and from an extensive multiwavelength imaging data set from the HST Advanced Camera for Surveys and ground-based facilities, of the cluster of galaxies RDCS J1252.9-2927. We have spectroscopically confirmed 38 cluster members in the redshift range 1.22 < z < 1.25. A cluster median redshift of z = 1.237 and a rest-frame velocity dispersion of 747-84 -74 km s-1 are obtained. Using the 38 confirmed redshifts, we were able to resolve, for the first time at z > 1, kinematic structure The velocity distribution, which is not Gaussian at the 95{\%} confidence level, is consistent with two groups that are also responsible for the projected east-west elongation of the cluster. The groups are composed of 26 and 12 galaxies with velocity dispersions of 486-85+47 and 426-105+57km s-1, respectively. The elongation is also seen in the intracluster gas and the dark matter distribution. This leads us to conclude that RDCS J1252.9-2927 has not yet reached a final virial state. We extend the analysis of the color-magnitude diagram of spectroscopic members to more than 1 Mpc from the cluster center. The scatter and slope of non-[O II]-emitting cluster members in the near-IR red sequence is similar to that seen in clusters at lower redshift. Furthermore, most of the galaxies with luminosities greater than ∼Ks*+1.5 do not show any [O n], indicating that these more luminous, redder galaxies have stopped forming stars earlier than the fainter, bluer galaxies. Our observations provide detailed dynamical and spectrophotometric information on galaxies in this exceptional high-redshift cluster, delivering an in-depth view of structure formation at this epoch only 5 Gyr after the big bang.",
author = "R. Demarco and P. Rosati and C. Lidman and M. Girardi and M. Nonino and A. Rettura and V. Strazzullo and {Van Der Wel}, A. and Ford, {H. C.} and V. Mainieri and Holden, {B. P.} and Stanford, {S. A.} and Blakeslee, {J. P.} and R. Gobat and M. Postman and P. Tozzi and Overzier, {R. A.} and Zirm, {A. W.} and N. Ben{\'i}tez and Homeier, {N. L.} and Illingworth, {G. D.} and L. Infante and Jee, {Myung Kook} and S. Mei and F. Menanteau and V. Motta and W. Zheng and M. Clampin and G. Hartig",
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Demarco, R, Rosati, P, Lidman, C, Girardi, M, Nonino, M, Rettura, A, Strazzullo, V, Van Der Wel, A, Ford, HC, Mainieri, V, Holden, BP, Stanford, SA, Blakeslee, JP, Gobat, R, Postman, M, Tozzi, P, Overzier, RA, Zirm, AW, Benítez, N, Homeier, NL, Illingworth, GD, Infante, L, Jee, MK, Mei, S, Menanteau, F, Motta, V, Zheng, W, Clampin, M & Hartig, G 2007, 'VLT and ACS observations of RDCS J1252.9-2927: Dynamical structure and galaxy populations in a massive cluster at z = 1.237', Astrophysical Journal, vol. 663, no. 1 I, pp. 164-182. https://doi.org/10.1086/518117

VLT and ACS observations of RDCS J1252.9-2927 : Dynamical structure and galaxy populations in a massive cluster at z = 1.237. / Demarco, R.; Rosati, P.; Lidman, C.; Girardi, M.; Nonino, M.; Rettura, A.; Strazzullo, V.; Van Der Wel, A.; Ford, H. C.; Mainieri, V.; Holden, B. P.; Stanford, S. A.; Blakeslee, J. P.; Gobat, R.; Postman, M.; Tozzi, P.; Overzier, R. A.; Zirm, A. W.; Benítez, N.; Homeier, N. L.; Illingworth, G. D.; Infante, L.; Jee, Myung Kook; Mei, S.; Menanteau, F.; Motta, V.; Zheng, W.; Clampin, M.; Hartig, G.

In: Astrophysical Journal, Vol. 663, No. 1 I, 01.07.2007, p. 164-182.

Research output: Contribution to journalArticle

TY - JOUR

T1 - VLT and ACS observations of RDCS J1252.9-2927

T2 - Dynamical structure and galaxy populations in a massive cluster at z = 1.237

AU - Demarco, R.

AU - Rosati, P.

AU - Lidman, C.

AU - Girardi, M.

AU - Nonino, M.

AU - Rettura, A.

AU - Strazzullo, V.

AU - Van Der Wel, A.

AU - Ford, H. C.

AU - Mainieri, V.

AU - Holden, B. P.

AU - Stanford, S. A.

AU - Blakeslee, J. P.

AU - Gobat, R.

AU - Postman, M.

AU - Tozzi, P.

AU - Overzier, R. A.

AU - Zirm, A. W.

AU - Benítez, N.

AU - Homeier, N. L.

AU - Illingworth, G. D.

AU - Infante, L.

AU - Jee, Myung Kook

AU - Mei, S.

AU - Menanteau, F.

AU - Motta, V.

AU - Zheng, W.

AU - Clampin, M.

AU - Hartig, G.

PY - 2007/7/1

Y1 - 2007/7/1

N2 - We present results from an extensive spectroscopic survey, carried out with VLT FORS, and from an extensive multiwavelength imaging data set from the HST Advanced Camera for Surveys and ground-based facilities, of the cluster of galaxies RDCS J1252.9-2927. We have spectroscopically confirmed 38 cluster members in the redshift range 1.22 < z < 1.25. A cluster median redshift of z = 1.237 and a rest-frame velocity dispersion of 747-84 -74 km s-1 are obtained. Using the 38 confirmed redshifts, we were able to resolve, for the first time at z > 1, kinematic structure The velocity distribution, which is not Gaussian at the 95% confidence level, is consistent with two groups that are also responsible for the projected east-west elongation of the cluster. The groups are composed of 26 and 12 galaxies with velocity dispersions of 486-85+47 and 426-105+57km s-1, respectively. The elongation is also seen in the intracluster gas and the dark matter distribution. This leads us to conclude that RDCS J1252.9-2927 has not yet reached a final virial state. We extend the analysis of the color-magnitude diagram of spectroscopic members to more than 1 Mpc from the cluster center. The scatter and slope of non-[O II]-emitting cluster members in the near-IR red sequence is similar to that seen in clusters at lower redshift. Furthermore, most of the galaxies with luminosities greater than ∼Ks*+1.5 do not show any [O n], indicating that these more luminous, redder galaxies have stopped forming stars earlier than the fainter, bluer galaxies. Our observations provide detailed dynamical and spectrophotometric information on galaxies in this exceptional high-redshift cluster, delivering an in-depth view of structure formation at this epoch only 5 Gyr after the big bang.

AB - We present results from an extensive spectroscopic survey, carried out with VLT FORS, and from an extensive multiwavelength imaging data set from the HST Advanced Camera for Surveys and ground-based facilities, of the cluster of galaxies RDCS J1252.9-2927. We have spectroscopically confirmed 38 cluster members in the redshift range 1.22 < z < 1.25. A cluster median redshift of z = 1.237 and a rest-frame velocity dispersion of 747-84 -74 km s-1 are obtained. Using the 38 confirmed redshifts, we were able to resolve, for the first time at z > 1, kinematic structure The velocity distribution, which is not Gaussian at the 95% confidence level, is consistent with two groups that are also responsible for the projected east-west elongation of the cluster. The groups are composed of 26 and 12 galaxies with velocity dispersions of 486-85+47 and 426-105+57km s-1, respectively. The elongation is also seen in the intracluster gas and the dark matter distribution. This leads us to conclude that RDCS J1252.9-2927 has not yet reached a final virial state. We extend the analysis of the color-magnitude diagram of spectroscopic members to more than 1 Mpc from the cluster center. The scatter and slope of non-[O II]-emitting cluster members in the near-IR red sequence is similar to that seen in clusters at lower redshift. Furthermore, most of the galaxies with luminosities greater than ∼Ks*+1.5 do not show any [O n], indicating that these more luminous, redder galaxies have stopped forming stars earlier than the fainter, bluer galaxies. Our observations provide detailed dynamical and spectrophotometric information on galaxies in this exceptional high-redshift cluster, delivering an in-depth view of structure formation at this epoch only 5 Gyr after the big bang.

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