MAGAZ3NE: Evidence for Galactic Conformity in z ≳ 3 Protoclusters

Ian McConachie; Gillian Wilson; Ben Forrest; Z. Cemile Marsan; Adam Muzzin; M. C. Cooper; Marianna Annunziatella; Danilo Marchesini; Percy Gomez; Wenjun Chang; Stephanie M. Urbano Stawinski; Michael McDonald; Tracy Webb; Allison Noble; Brian C. Lemaux; Ekta A. Shah; Priti Staab; Lori M. Lubin; Roy R. Gal

doi:10.3847/1538-4357/ad8f36

MAGAZ3NE: Evidence for Galactic Conformity in z ≳ 3 Protoclusters

Ian McConachie
, Gillian Wilson
, Ben Forrest
, Z. Cemile Marsan
, Adam Muzzin
, M. C. Cooper
, Marianna Annunziatella
, Danilo Marchesini
, Percy Gomez
, Wenjun Chang
, Stephanie M. Urbano Stawinski
, Michael McDonald
, Tracy Webb
, Allison Noble
, Brian C. Lemaux
, Ekta A. Shah
, Priti Staab
, Lori M. Lubin
, Roy R. Gal

Research output: Contribution to journal › Article › peer-review

9 Scopus citations

Abstract

We examine the quiescent fractions of massive galaxies in six z ≳ 3 spectroscopically confirmed protoclusters in the COSMOS field, one of which is newly confirmed and presented here. We report the spectroscopic confirmation of MAGAZ3NE J100143+023021 at z = 3.122 − 0.004 + 0.007 by the Massive Ancient Galaxies At z > 3 NEar-infrared (MAGAZ3NE) survey. MAGAZ3NE J100143+023021 contains a total of 79 protocluster members (28 spectroscopic and 51 photometric). Three spectroscopically confirmed members are star-forming ultramassive galaxies (UMGs; log ( M ⋆ / M ⊙ ) > 11), the most massive of which has log ( M ⋆ / M ⊙ ) = 11.15 − 0.06 + 0.05 . Combining Keck/MOSFIRE spectroscopy and the COSMOS2020 photometric catalog, we use a weighted Gaussian kernel density estimator to map the protocluster and measure its total mass 2.25 − 0.65 + 1.55 × 10 14 M ⊙ in the dense “core” region. For each of the six COSMOS protoclusters, we compare the quiescent fraction to the status of the central UMG as star-forming or quiescent. We observe that galaxies in these protoclusters appear to obey galactic conformity: Elevated quiescent fractions are found in protoclusters with UVJ-quiescent UMGs and low quiescent fractions are found in protoclusters containing UVJ star-frming UMGs. This correlation of star formation/quiescence in UMGs and the massive galaxies nearby in these protoclusters is the first evidence for the existence of galactic conformity at z > 3. Despite disagreements over mechanisms behind conformity at low redshifts, its presence at these early cosmic times would provide strong constraints on the physics proposed to drive galactic conformity.

Original language	English (US)
Article number	17
Journal	Astrophysical Journal
Volume	978
Issue number	1
DOIs	https://doi.org/10.3847/1538-4357/ad8f36
State	Published - Jan 1 2025
Externally published	Yes

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.3847/1538-4357/ad8f36

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McConachie, I., Wilson, G., Forrest, B., Marsan, Z. C., Muzzin, A., Cooper, M. C., Annunziatella, M., Marchesini, D., Gomez, P., Chang, W., Urbano Stawinski, S. M., McDonald, M., Webb, T., Noble, A., Lemaux, B. C., Shah, E. A., Staab, P., Lubin, L. M., & Gal, R. R. (2025). MAGAZ3NE: Evidence for Galactic Conformity in z ≳ 3 Protoclusters. Astrophysical Journal, 978(1), Article 17. https://doi.org/10.3847/1538-4357/ad8f36

McConachie, I, Wilson, G, Forrest, B, Marsan, ZC, Muzzin, A, Cooper, MC, Annunziatella, M, Marchesini, D, Gomez, P, Chang, W, Urbano Stawinski, SM, McDonald, M, Webb, T, Noble, A, Lemaux, BC, Shah, EA, Staab, P, Lubin, LM & Gal, RR 2025, 'MAGAZ3NE: Evidence for Galactic Conformity in z ≳ 3 Protoclusters', Astrophysical Journal, vol. 978, no. 1, 17. https://doi.org/10.3847/1538-4357/ad8f36

@article{7764b80b86de45b3b27f816db4d90730,

title = "MAGAZ3NE: Evidence for Galactic Conformity in z ≳ 3 Protoclusters",

abstract = "We examine the quiescent fractions of massive galaxies in six z ≳ 3 spectroscopically confirmed protoclusters in the COSMOS field, one of which is newly confirmed and presented here. We report the spectroscopic confirmation of MAGAZ3NE J100143+023021 at z = 3.122 − 0.004 + 0.007 by the Massive Ancient Galaxies At z > 3 NEar-infrared (MAGAZ3NE) survey. MAGAZ3NE J100143+023021 contains a total of 79 protocluster members (28 spectroscopic and 51 photometric). Three spectroscopically confirmed members are star-forming ultramassive galaxies (UMGs; log ( M ⋆ / M ⊙ ) > 11), the most massive of which has log ( M ⋆ / M ⊙ ) = 11.15 − 0.06 + 0.05 . Combining Keck/MOSFIRE spectroscopy and the COSMOS2020 photometric catalog, we use a weighted Gaussian kernel density estimator to map the protocluster and measure its total mass 2.25 − 0.65 + 1.55 × 10 14 M ⊙ in the dense “core” region. For each of the six COSMOS protoclusters, we compare the quiescent fraction to the status of the central UMG as star-forming or quiescent. We observe that galaxies in these protoclusters appear to obey galactic conformity: Elevated quiescent fractions are found in protoclusters with UVJ-quiescent UMGs and low quiescent fractions are found in protoclusters containing UVJ star-frming UMGs. This correlation of star formation/quiescence in UMGs and the massive galaxies nearby in these protoclusters is the first evidence for the existence of galactic conformity at z > 3. Despite disagreements over mechanisms behind conformity at low redshifts, its presence at these early cosmic times would provide strong constraints on the physics proposed to drive galactic conformity.",

author = "Ian McConachie and Gillian Wilson and Ben Forrest and Marsan, \{Z. Cemile\} and Adam Muzzin and Cooper, \{M. C.\} and Marianna Annunziatella and Danilo Marchesini and Percy Gomez and Wenjun Chang and \{Urbano Stawinski\}, \{Stephanie M.\} and Michael McDonald and Tracy Webb and Allison Noble and Lemaux, \{Brian C.\} and Shah, \{Ekta A.\} and Priti Staab and Lubin, \{Lori M.\} and Gal, \{Roy R.\}",

note = "Publisher Copyright: {\textcopyright} 2024. The Author(s). Published by the American Astronomical Society.",

year = "2025",

month = jan,

day = "1",

doi = "10.3847/1538-4357/ad8f36",

language = "English (US)",

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TY - JOUR

T1 - MAGAZ3NE

T2 - Evidence for Galactic Conformity in z ≳ 3 Protoclusters

AU - McConachie, Ian

AU - Wilson, Gillian

AU - Forrest, Ben

AU - Marsan, Z. Cemile

AU - Muzzin, Adam

AU - Cooper, M. C.

AU - Annunziatella, Marianna

AU - Marchesini, Danilo

AU - Gomez, Percy

AU - Chang, Wenjun

AU - Urbano Stawinski, Stephanie M.

AU - McDonald, Michael

AU - Webb, Tracy

AU - Noble, Allison

AU - Lemaux, Brian C.

AU - Shah, Ekta A.

AU - Staab, Priti

AU - Lubin, Lori M.

AU - Gal, Roy R.

PY - 2025/1/1

Y1 - 2025/1/1

N2 - We examine the quiescent fractions of massive galaxies in six z ≳ 3 spectroscopically confirmed protoclusters in the COSMOS field, one of which is newly confirmed and presented here. We report the spectroscopic confirmation of MAGAZ3NE J100143+023021 at z = 3.122 − 0.004 + 0.007 by the Massive Ancient Galaxies At z > 3 NEar-infrared (MAGAZ3NE) survey. MAGAZ3NE J100143+023021 contains a total of 79 protocluster members (28 spectroscopic and 51 photometric). Three spectroscopically confirmed members are star-forming ultramassive galaxies (UMGs; log ( M ⋆ / M ⊙ ) > 11), the most massive of which has log ( M ⋆ / M ⊙ ) = 11.15 − 0.06 + 0.05 . Combining Keck/MOSFIRE spectroscopy and the COSMOS2020 photometric catalog, we use a weighted Gaussian kernel density estimator to map the protocluster and measure its total mass 2.25 − 0.65 + 1.55 × 10 14 M ⊙ in the dense “core” region. For each of the six COSMOS protoclusters, we compare the quiescent fraction to the status of the central UMG as star-forming or quiescent. We observe that galaxies in these protoclusters appear to obey galactic conformity: Elevated quiescent fractions are found in protoclusters with UVJ-quiescent UMGs and low quiescent fractions are found in protoclusters containing UVJ star-frming UMGs. This correlation of star formation/quiescence in UMGs and the massive galaxies nearby in these protoclusters is the first evidence for the existence of galactic conformity at z > 3. Despite disagreements over mechanisms behind conformity at low redshifts, its presence at these early cosmic times would provide strong constraints on the physics proposed to drive galactic conformity.

AB - We examine the quiescent fractions of massive galaxies in six z ≳ 3 spectroscopically confirmed protoclusters in the COSMOS field, one of which is newly confirmed and presented here. We report the spectroscopic confirmation of MAGAZ3NE J100143+023021 at z = 3.122 − 0.004 + 0.007 by the Massive Ancient Galaxies At z > 3 NEar-infrared (MAGAZ3NE) survey. MAGAZ3NE J100143+023021 contains a total of 79 protocluster members (28 spectroscopic and 51 photometric). Three spectroscopically confirmed members are star-forming ultramassive galaxies (UMGs; log ( M ⋆ / M ⊙ ) > 11), the most massive of which has log ( M ⋆ / M ⊙ ) = 11.15 − 0.06 + 0.05 . Combining Keck/MOSFIRE spectroscopy and the COSMOS2020 photometric catalog, we use a weighted Gaussian kernel density estimator to map the protocluster and measure its total mass 2.25 − 0.65 + 1.55 × 10 14 M ⊙ in the dense “core” region. For each of the six COSMOS protoclusters, we compare the quiescent fraction to the status of the central UMG as star-forming or quiescent. We observe that galaxies in these protoclusters appear to obey galactic conformity: Elevated quiescent fractions are found in protoclusters with UVJ-quiescent UMGs and low quiescent fractions are found in protoclusters containing UVJ star-frming UMGs. This correlation of star formation/quiescence in UMGs and the massive galaxies nearby in these protoclusters is the first evidence for the existence of galactic conformity at z > 3. Despite disagreements over mechanisms behind conformity at low redshifts, its presence at these early cosmic times would provide strong constraints on the physics proposed to drive galactic conformity.

UR - https://www.scopus.com/pages/publications/86000183088

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JO - Astrophysical Journal

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MAGAZ3NE: Evidence for Galactic Conformity in z ≳ 3 Protoclusters

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