The environmental dependence of galaxy properties at<i>z</i> = 2

Tanaka, Masayuki; Breuck, C. De; Venemans, Bram; Kurk, J.

doi:10.1051/0004-6361/200913939

Cited by 70 publications

(104 citation statements)

References 61 publications

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“…Other works have found overdensities in the near-IR (Kajisawa et al 2006), of Hα emitters (Tanaka et al 2011) and mid-IR (G12). This work finds a 24 μm source overdensity at a 4.7σ level.…”

Section: C2356 (Z = 2483)mentioning

confidence: 86%

Overdensities of 24 μm sources in the vicinities of high-redshift radio galaxies

Mayo

Vernet

Breuck

et al. 2012

A&A

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We present a statistical study of the environments of 63 high-redshift radio galaxies (HzRGs) between redshifts 1 ≤ z ≤ 5.2, using the 24 μm waveband of the MIPS instrument aboard the Spitzer Space Telescope. Using a counts-in-cell analysis, a statistically significant source overdensity is found in 1.75 radius circular cells centred on the HzRGs when compared to reference fields. We report an average overdensity of δ (=N targets /N reference ) = 2.2 ± 1.2 at a flux density cut of f 24 μm = 0.3 mJy. This result implies that HzRGs are likely to lie in protoclusters of active and star-forming galaxies at high redshift. Over 95% of our targeted HzRGs lie in higher than average density fields. Further, 20 (32%) of our selected fields are found to be overdense to at least a 3σ significance, of which 9 are newly identified protocluster candidates. We observe a weak correlation between redshift and 24 μm source density, and discuss the populations being probed at different redshifts. In our uniformly selected sample, which was designed to cover two orders of magnitude in radio luminosity throughout z = 1−4, we find that the 24 μm source density does not depend on radio luminosity. We also compare this result with recent work describing IRAC source overdensities around the same HzRGs and find correlations between the results.

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Section: C2356 (Z = 2483)mentioning

confidence: 86%

Overdensities of 24 μm sources in the vicinities of high-redshift radio galaxies

Mayo

Vernet

Breuck

et al. 2012

A&A

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“…4 from the nominal LABOCA position, and not to the AGN at z = 1.5. No spectroscopic redshift is known for this radio source, but both the optical/NIR photometric redshift of z opt/NIR = 2.12 +0.13 −0.20 (Tanaka et al 2010) and the FIR photometric redshift of z FIR = 2.7 ± 0.8 means this SMG is a plausible protocluster member. Finally, we note that 8.…”

Section: Smm J1140533−262913 (Dkb02 (P)ossible Member)mentioning

confidence: 99%

An excess of dusty starbursts related to the Spiderweb galaxy

Dannerbauer

Kurk

Breuck

et al. 2014

A&A

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We present APEX LABOCA 870 μm observations of the field around the high-redshift radio galaxy MRC1138−262 at z = 2.16. We detect 16 submillimeter galaxies (SMGs) in this ∼140 arcmin 2 bolometer map with flux densities in the range 3-11 mJy. The raw number counts indicate a density of SMGs that is up to four times that of blank field surveys. Based on an exquisite multiwavelength database, including VLA 1.4 GHz radio and infrared observations, we investigate whether these sources are members of the protocluster structure at z ≈ 2.2. Using Herschel PACS and SPIRE and Spitzer MIPS photometry, we derive reliable far-infrared (FIR) photometric redshifts for all sources. Follow-up VLT ISAAC and SINFONI NIR spectra confirm that four of these SMGs have redshifts of z ≈ 2.2. We also present evidence that another SMG in this field, detected earlier at 850 μm, has a counterpart that exhibits Hα and CO(1-0) emission at z = 2.15. Including the radio galaxy and two SMGs with FIR photometric redshifts at z = 2.2, we conclude that at least eight submm sources are part of the protocluster at z = 2.16 associated with the radio galaxy MRC1138−262. We measure a star formation rate density SFRD ∼1500 M yr −1 Mpc −3 , four magnitudes higher than the global SFRD of blank fields at this redshift. Strikingly, these eight sources are concentrated within a region of 2 Mpc (the typical size of clusters in the local universe) and are distributed within the filaments traced by the HAEs at z ≈ 2.2. This concentration of massive, dusty starbursts is not centered on the submillimeter-bright radio galaxy which could support the infalling of these sources into the cluster center. Approximately half (6/11) of the SMGs that are covered by the Hα imaging data are associated with HAEs, demonstrating the potential of tracing SMG counterparts with this population. To summarize, our results demonstrate that submillimeter observations may enable us to study (proto)clusters of massive, dusty starbursts.

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“…The field has been imaged with LRIS on Keck (U band; Zirm et al 2008), FORS on the Very Large Telescope (R and z), the Advanced Camera for Surveys on the Hubble Space Telescope (g and I; Miley et al 2006), MOIRCS on Subaru (J and K s ; Kodama et al 2007), SOFI on the New Technology Telescope (H; Kodama et al 2007), and IRAC on Spitzer (3.6-8.0 μm; Seymour et al 2007). We base our analysis on an updated version of the multiband catalog presented in Tanaka et al (2010b). We primarily used MAG_AUTO from SExtractor (Bertin & Arnouts 1996) in the original catalog, but this resulted in somewhat erroneous photometry particularly for faint objects.…”

Section: Multi-wavelength Catalog Of Pks1138mentioning

confidence: 99%

“…PKS1138-26 is a powerful radio galaxy located at z = 2.16 and it has been intensively studied by many authors, providing robust evidence for a forming cluster (Pentericci et al 1997(Pentericci et al , 1998(Pentericci et al , 2002Kurk et al 2000Kurk et al , 2004aKurk et al , 2004bCroft et al 2005;Miley et al 2006;Kodama et al 2007;Zirm et al 2008;Hatch et al 2008Hatch et al , 2009Doherty et al 2010;Tanaka et al 2010b;Koyama et al 2013). A wealth of imaging data as well as a large number of spectroscopic redshifts are available in this field, making it an unique place to investigate the question raised above.…”

Section: Introductionmentioning

confidence: 99%

ON THE FORMATION TIMESCALE OF MASSIVE CLUSTER ELLIPTICALS BASED ON DEEP NEAR-INFRARED SPECTROSCOPY ATz∼ 2

Tanaka

Toft

Marchesini

et al. 2013

ApJ

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We present improved constraints on the formation timescale of massive cluster galaxies based on rest-frame optical spectra of galaxies in a forming cluster located at z = 2.16. The spectra are obtained with MOIRCS on the Subaru Telescope with an integration time of ∼7 hr. We achieve accurate redshift measurements by fitting spectral energy distributions using the spectra and broadband photometry simultaneously, allowing us to identify probable cluster members. Clusters at low redshifts are dominated by quiescent galaxies, but we find that quiescent galaxies and star-forming galaxies coexist in this z = 2 system. Interestingly, the quiescent galaxies form a weak red sequence in the process of forming. By stacking the spectra of star-forming galaxies, we observe strong emission lines such as [O ii] and [O iii] and we obtain a tentative hint of active galactic nucleus activities in these galaxies. On the other hand, the stacked spectrum of the quiescent galaxies reveals a clear 4000 Å break with a possible Ca ii H+K absorption feature and strong emission lines such as [O ii] are absent in the spectrum, confirming the quiescent nature of these galaxies. We then perform detailed spectral analyses of the stacked spectrum, which suggest that these massive quiescent galaxies formed at redshifts between 3 and 4 on a timescale of 0.5 Gyr. This short formation timescale is not reproduced in recent numerical simulations. We discuss possible mechanisms for how these galaxies form 10 11 M stellar mass on a short timescale and become red and quiescent by z = 2.

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The environmental dependence of galaxy properties atz = 2

Cited by 70 publications

References 61 publications

Overdensities of 24 μm sources in the vicinities of high-redshift radio galaxies

Overdensities of 24 μm sources in the vicinities of high-redshift radio galaxies

An excess of dusty starbursts related to the Spiderweb galaxy

ON THE FORMATION TIMESCALE OF MASSIVE CLUSTER ELLIPTICALS BASED ON DEEP NEAR-INFRARED SPECTROSCOPY ATz∼ 2

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