COMPACT QUIESCENT GALAXIES AT INTERMEDIATE REDSHIFTS<sup>,</sup>

Hsu, Li‐Che; Stockton, Alan; Shih, Hsin-Yi

doi:10.1088/0004-637x/796/2/92

Cited by 37 publications

(66 citation statements)

References 72 publications

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“…Top panel: The respective fractions of HIEROs and LBGs for galaxies with M * > 10 10.5 M ⊙ . Hsu et al (2014), yielding similar results on the fraction of massive galaxies selected as H-dropouts and HIEROs in general. These results suggest that the HIEROs dominate the high-mass end of the stellar mass function at z > 3, and their properties are thus representative of the massive galaxies at these redshifts.…”

Section: Completeness Of the Hiero Selection For Massive Galaxies At Z >supporting

confidence: 71%

Infrared color selection of massive galaxies at z > 3

Wang,

Elbaz,

Schreiber

et al. 2015

Preprint

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We introduce a new color-selection technique to identify high-redshift, massive galaxies that are systematically missed by Lyman-break selection. The new selection is based on the H 160 (H) and Infrared Array Camera (IRAC) 4.5 µm bands, specifically H − [4.5] > 2.25 mag. These galaxies, dubbed "HIEROs", include two major populations that can be separated with an additional J − H color. The populations are massive and dusty star-forming galaxies at z > 3 (JH-blue) and extremely dusty galaxies at z 3 (JH-red). The 350 arcmin 2 of the GOODS-North and GOODS-South fields with the deepest HST/WFC3 near-infrared and IRAC data contain as many as 285 HIEROs down to [4.5] < 24 mag. Inclusion of the most extreme HIEROs, not even detected in the H band, makes this selection particularly complete for the identification of massive high-redshift galaxies. We focus here primarily on JH-blue (z > 3) HIEROs, which have a median photometric redshift z ∼ 4.4 and stellar mass M * ∼ 10 10.6 M ⊙ and are much fainter in the rest-frame UV than similarly massive Lyman-break galaxies (LBGs). Their star formation rates (SFRs), derived from their stacked infrared spectral energy distributions, reach ∼240 M ⊙ yr −1 leading to a specific SFR, sSFR ≡ SFR/M * ∼ 4.2 Gyr −1 , suggesting that the sSFRs for massive galaxies continue to grow at z > 2 but at a lower growth rate than from z = 0 to z = 2. With a median half-light radius of 2 kpc, including ∼20% as compact as quiescent galaxies at similar redshifts, JH-blue HIEROs represent perfect star-forming progenitors of the most massive (M * 10 11.2 M ⊙ ) compact quiescent galaxies at z ∼ 3 and have the right number density. HIEROs make up ∼60% of all galaxies with M * > 10 10.5 M ⊙ identified at z > 3 from their photometric redshifts. This is five times more than LBGs with nearly no overlap between the two populations. While HIEROs make up 15-25% of the total SFR density at z ∼ 4-5, they completely dominate the SFR density taking place in M * > 10 10.5 M ⊙ galaxies, and HIEROs are therefore crucial to understanding the very early phase of massive galaxy formation.

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Section: Completeness Of the Hiero Selection For Massive Galaxies At Z >supporting

confidence: 71%

Infrared color selection of massive galaxies at z > 3

Wang,

Elbaz,

Schreiber

et al. 2015

Preprint

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“…Its location in the dusty-sU V J could be due to residual obscured star-formation, which could also be responsible of the marginal 24 µm/MIPS detection of the object (2.5σ, see Section 4, and Table 1). It is also possible that the AGN partly, or totally, contributes to the low MIPS emission of the source, and that its odd position on the U V J diagram is instead due to a higher redshift with respect to the photo-z quoted here (Grazian et al 2006, for instance, Luo et al 2010and Hsu et al 2014 report z phot ≃ 2.5).…”

Section: A Few Odd Casesmentioning

confidence: 88%

Star formation and quenching among the most massive galaxies at z ∼ 1.7

Mancini¹,

Renzini²,

Daddi³

et al. 2015

Monthly Notices of the Royal Astronomical Society

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We have conducted a detailed object-by-object study of a mass-complete (M * 10 11 M ⊙ ) sample of 56 galaxies at 1.4 z 2 in the GOODS-South field, showing that an accurate de-blending in MIPS/24um images is essential to properly assign to each galaxy its own star formation rate (SFR), whereas an automatic procedure often fails. This applies especially to galaxies with SFRs below the Main Sequence (MS) value, which may be in their quenching phase. After that, the sample splits evenly between galaxies forming stars within a factor of 4 of the MS rate (∼ 45%), and sub-MS galaxies with SFRs ∼ 10 − 1000 times smaller (∼ 55%). We did not find a well defined class of intermediate, transient objects below the MS, suggesting that the conversion of a massive MS galaxy into a quenched remnant may take a relatively short time (< 1 Gyr), though a larger sample should be analyzed in the same way to set precise limits on the quenching timescale. X-ray detected AGNs represent a ∼ 30% fraction of the sample, and are found among both star-forming and quenched galaxies. The morphological analysis revealed that ∼ 50% of our massive objects are bulge-dominated, and almost all MS galaxies with a relevant bulge component host an AGN. We also found sub-MS SFRs in many bulge-dominated systems, providing support to the notion that bulge growth, AGN activity and quenching of star formation are closely related to each other.

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“…However there is a growing body of indirect evidence that quiescent galaxies may grow more “disky” and rotation dominated with redshift. A number of studies have found a fraction of quiescent galaxies to have exponential disk like surface brightness profiles, both at high11,13,56,57 and intermediate redshifts58. Indeed, the best candidate low redshift direct descendant of a z=2 cQG was found to be a rapidly rotating exponential disk59.…”

Section: Methodsmentioning

confidence: 99%

A massive, dead disk galaxy in the early Universe

Toft

Zabl

Richard

et al. 2017

Nature

110

138

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At redshift z = 2, when the Universe was just three billion years old, half of the most massive galaxies were extremely compact and had already exhausted their fuel for star formation [1][2][3][4] . It is believed that they were formed in intense nuclear starbursts and that they ultimately grew into the most massive local elliptical galaxies seen today, through mergers with minor companions 5,6 , but validating this picture requires higher-resolution observations of their centres than is currently possible. Magnification from gravitational lensing offers an opportunity to resolve the inner regions of galaxies 7 . Here we report an analysis of the stellar populations and kinematics of a lensed z = 2.1478 compact galaxy, which-surprisingly-turns out to be a fast-spinning, rotationally supported disk galaxy. Its stars must have formed in a disk, rather than in a merger-driven nuclear starburst 8 . The galaxy was probably fed by streams of cold gas, which were able to penetrate the hot halo gas until they were cut off by shock heating from the dark matter halo 9 . This result confirms previous indirect indications 10-13 that the first galaxies to cease star formation must have gone through major changes not just in their structure, but also in their kinematics, to evolve into present-day elliptical galaxies.We obtained deep spectroscopy using the XSHOOTER instrument on the Very Large Telescope (VLT) of a compact quiescent galaxy that is gravitationally lensed by the z = 0.588 cluster of galaxies MACS J2129.4−0741 (hereafter MACS2129−1; ref. 14; (Extended Data Fig. 1), and as a consequence appears 4.6 ± 0.2 times brighter and extends over 3″ on the sky. In Fig.1, we show the position of the XSHOOTER slit on a Hubble Space Telescope (HST) colour-composite image and on the reconstructed source plane. The galaxy is stretched along its major axis and we derive a spatially resolved spectrum typical of quiescent z ≈ 2 post-starburst galaxies, with a strong Balmer break and a number of strong absorption features. We fit a spectroscopic redshift of z = 2.1478 ± 0.0006 and constrain the stellar populations through modeling of the rest-frame ultraviolet-to-optical spectrum, the absorption line indices, and the spatially integrated rest-frame ultravioletto-near-infrared (NIR) colours derived from 16-band HST/Infrared Array Camera (IRAC) photometry. The best-fitting spectrum reveals a massive, old, post-starburst Table 1). We derive a velocity dispersion of σ=329±73 km s -1 from absorption lines in the spatially integrated spectrum (Fig. 1) using a penalized pixel fitting method (pPXF) 15 with the best-fitting spectral energy distribution model as a template. Interestingly, the absorption lines are tilted in the twodimensional spectrum. We extract individual rows that represent approximately 0.4-kpc bins along the major axis on the source plane. The central 11 rows have sufficient signal to noise (S/N) to detect absorption lines reliably. We fit each row with the same pPXF implementation used for the spatially integrated spec...

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COMPACT QUIESCENT GALAXIES AT INTERMEDIATE REDSHIFTS^,

Cited by 37 publications

References 72 publications

Infrared color selection of massive galaxies at z > 3

Infrared color selection of massive galaxies at z > 3

Star formation and quenching among the most massive galaxies at z ∼ 1.7

A massive, dead disk galaxy in the early Universe

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COMPACT QUIESCENT GALAXIES AT INTERMEDIATE REDSHIFTS,

Cited by 37 publications

References 72 publications

Infrared color selection of massive galaxies at z > 3

Infrared color selection of massive galaxies at z > 3

Star formation and quenching among the most massive galaxies at z ∼ 1.7

A massive, dead disk galaxy in the early Universe

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Product

Resources

About

COMPACT QUIESCENT GALAXIES AT INTERMEDIATE REDSHIFTS^,