Searching for an Early Epoch of Star Formation with MM/Sub-MM Blank Field Surveys

There is now good agreement between the various methods of estimating the space density of the star-formation rate (SFRD) at low redshifts (z < 1), with uncertainties around 30–50%. However, the situation at higher redshifts remains much less clear, with uncertainties in the SFRD, due to e.g. poorly known dust absorption corrections, of as much as 300–500%. Radio emission from star-forming galaxies is unaffected by absorption and scales linearly with star-formation rate, thus the radio luminosity of star-forming galaxies provides an excellent independent, unbiased measure of their star-formation rate. The current deepest ‘blank field’ radio surveys (reaching <10 μJy rms at 1.4 GHz) are sensitive enough to detect starburst galaxies out to z ~ 3, and so potentially offer an excellent way to measure the SFRD. Indeed, modelling of the sub-mJy source counts requires an additional population of faint steep spectrum objects, that are very likely to be starburst galaxies.

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Two sub-millimetre bright protoclusters bounding the epoch of peak star-formation activity

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1742 ◽

2019 ◽

Vol 488 (2) ◽

pp. 1790-1812 ◽

Cited By ~ 8

Author(s):

Kevin M Lacaille ◽

Scott C Chapman ◽

Ian Smail ◽

C C Steidel ◽

A W Blain ◽

...

Keyword(s):

Star Formation ◽

Field Surveys ◽

Star Forming ◽

James Clerk Maxwell ◽

Bolometer Array ◽

Star Formation Activity ◽

Diameter Core ◽

Dense Cluster ◽

Cluster Cores ◽

Number Counts

ABSTRACT We present James Clerk Maxwell Telescope Submillimetre Common-User Bolometer Array 2 (SCUBA-2) 850 and 450 $\mu$m observations (σ850 ∼ 0.5 mJy, σ450 ∼ 5 mJy) of the HS1549+19 and HS1700+64 survey fields containing two of the largest known galaxy overdensities at z = 2.85 and 2.30, respectively. We detect 56 sub-millimetre galaxies (SMGs) with SNR > 4 over ∼50 arcmin2 at 850 $\mu$m with flux densities of 3–17 mJy. The number counts indicate overdensities in the 3-arcmin diameter core region (∼1.5 Mpc at z = 2.5) of $6^{+4}_{-2}\times$ (HS1549) and $4^{+6}_{-2}\times$ (HS1700) compared to blank field surveys. Within these core regions, we spectroscopically confirm that approximately one-third of the SMGs lie at the protocluster redshifts for both HS1549 and HS1700. We use statistical identifications of other SMGs in the wider fields to constrain an additional four candidate protocluster members in each system. We combine multiwavelength estimates of the star-formation rates (SFRs) from Lyman-break dropout- and narrow-band-selected galaxies, and the SCUBA-2 SMGs, to estimate total SFRs of 12 500 ± 2800 M⊙ yr−1 (4900 ± 1200 M⊙ yr−1) in HS1549 (HS1700), and SFR densities (SFRDs) within the central 1.5-Mpc diameter of each protocluster to be 3000 ± 900 M⊙ yr−1 Mpc−3 (1300 ± 400 M⊙ yr−1 Mpc−3) in the HS1549 (HS1700) protocluster, ∼104 × larger than the global SFRDs found at their respective epochs, due to the concentration of star-forming galaxies in the small volume of the dense cluster cores. Our results suggest centrally concentrated starbursts within protoclusters may be a relatively common scenario for the build-up of mass in rich clusters assembling at z ≳ 2.

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Observable Properties of Passively-Evolving Galaxies at High Redshift

Symposium - International Astronomical Union ◽

10.1017/s0074180900233901 ◽

1996 ◽

Vol 171 ◽

pp. 472-472 ◽

Cited By ~ 1

Author(s):

Toru Yamada ◽

Nobuo Arimoto

Keyword(s):

Star Formation ◽

High Redshift ◽

Early Type ◽

Rich Cluster ◽

Early Epoch ◽

Conspicuous Feature ◽

Cluster Environment

There are evidenves which suggest that many of the early-type galaxies in rich cluster environment formed at fairly high redshift, z > 2. If the galaxies formed at such early epoch have experienced no intensive star-formation events, their photometric properties can be traced with less ambiguity by using the stellar evolutionary sinthesis models. Here we demonstrate what conspicuous feature can be observed for those passively-evolving galaxies at high redshift and how we can constrain the epoch and period of their formation.

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ALMA twenty-six arcmin2 survey of GOODS-S at one millimeter (ASAGAO)

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319009542 ◽

2019 ◽

Vol 15 (S352) ◽

pp. 239-240

Author(s):

B. Hatsukade ◽

K. Kohno ◽

Y. Yamaguchi ◽

H. Umehata ◽

Y. Ao ◽

...

Keyword(s):

Archival Data ◽

Beam Size ◽

Density Evolution ◽

Extragalactic Background Light ◽

Field Surveys ◽

Blank Field ◽

Background Light ◽

Luminosity Functions ◽

Number Counts ◽

Luminosity Evolution

AbstractThe ALMA twenty-six arcmin2 survey of GOODS-S at one millimeter (ASAGAO) is a deep (1σ ∼ 61μJy/beam) and wide area (26 arcmin2) survey on a contiguous field at 1.2 mm. By combining with archival data, we obtained a deeper map in the same region (1σ ∼ 30μJy/beam−1, synthesized beam size 0.59″ × 0.53″), providing the largest sample of sources (25 sources at 5σ, 45 sources at 4.5σ) among ALMA blank-field surveys. The median redshift of the 4.5σ sources is 2.4. The number counts shows that 52% of the extragalactic background light at 1.2 mm is resolved into discrete sources. We create IR luminosity functions (LFs) at z = 1–3, and constrain the faintest luminosity of the LF at 2 < z < 3. The LFs are consistent with previous results based on other ALMA and SCUBA-2 observations, which suggests a positive luminosity evolution and negative density evolution.

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THE PRIMEVAL STRUCTURE TELESCOPE

Modern Physics Letters A ◽

10.1142/s0217732304014288 ◽

2004 ◽

Vol 19 (13n16) ◽

pp. 1001-1008 ◽

Cited By ~ 5

Author(s):

JEFFERY B. PETERSON ◽

UE-LI PEN ◽

XIANG-PING WU

Keyword(s):

Star Formation ◽

Large Scale ◽

Neutral Hydrogen ◽

Large Scale Structure ◽

Density Structure ◽

First Stars ◽

Early Epoch ◽

The Past ◽

Cosmic Background ◽

Luminous Objects

The PrimevAl Structure Telescope (PAST), will be used to locate and study the era the of the first luminous objects, the epoch of reionization. The first stars ionized the gas around them producing a pattern of ionization that reflects the large scale density structure present at the time. The PAST array will be used to sense and study this ionization, by mapping the brightness of 21 cm neutral Hydrogen Cosmic Background (HCB) at redshift from 6 to 25. The HCB disappears on ionization, allowing the study of large scale structure and of star formation at this very early epoch.

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A SCUBA-2 850 μm survey of heavily reddened quasars at z ∼ 2

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa224 ◽

2020 ◽

Vol 492 (4) ◽

pp. 5280-5290

Author(s):

Clare F Wethers ◽

Manda Banerji ◽

Paul C Hewett ◽

Gareth C Jones

Keyword(s):

Star Formation ◽

Small Sample ◽

Large Contribution ◽

Type I ◽

Host Galaxies ◽

Field Surveys ◽

Flux Limit ◽

Small Sample Sizes ◽

Number Counts ◽

Very High

ABSTRACT We present new 850 μm SCUBA-2 observations for a sample of 19 heavily reddened Type-I quasars at redshifts z ∼ 2 with dust extinctions of AV ≃ 2–6 mag. Three of the 19 quasars are detected at >3σ significance corresponding to an 850 μm flux-limit of ≳4.8 mJy. Assuming the 850 μm flux is dominated by dust heating due to star formation, very high star formation rates (SFR) of ∼2500–4500 M⊙ yr−1 in the quasar host galaxies are inferred. Even when considering a large contribution to the 850 μm flux from dust heated by the quasar itself, significant SFRs of ∼600–1500 M⊙ yr−1 are nevertheless inferred for two of the three detected quasars. We stack the remaining 16 heavily reddened quasars and derive an average 3σ upper limit on the SFRs in these quasar host galaxies of <880 M⊙ yr−1. The number counts of sub-mm galaxies in the total survey area (134.3 arcmin2) are consistent with predictions from blank-field surveys. There are, however, individual quasars where we find evidence for an excess of associated sub-mm galaxies. For two quasars, higher spatial resolution and spectroscopic ALMA observations confirm the presence of an excess of sub-mm sources. We compare the 850 μm detection rate of our quasars to both unobscured, ultraviolet luminous quasars as well as the much more obscured population of mid-infrared luminous Hot Dust Obscured Galaxies (HotDOGs). When matched by luminosity and redshift, we find no significant differences in the 850 μm flux densities of these various quasar populations given the current small sample sizes.

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