scholarly journals A high redshift population of galaxies at the North Ecliptic Pole

2020 ◽  
Vol 641 ◽  
pp. A129 ◽  
Author(s):  
L. Barrufet ◽  
C. Pearson ◽  
S. Serjeant ◽  
K. Małek ◽  
I. Baronchelli ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Physical Parameters ◽  
Distribution Fitting ◽  
Star Forming ◽  
The North ◽  
Multi Wavelength

Context. Dusty high-z galaxies are extreme objects with high star formation rates (SFRs) and luminosities. Characterising the properties of this population and analysing their evolution over cosmic time is key to understanding galaxy evolution in the early Universe. Aims. We select a sample of high-z dusty star-forming galaxies (DSFGs) and evaluate their position on the main sequence (MS) of star-forming galaxies, the well-known correlation between stellar mass and SFR. We aim to understand the causes of their high star formation and quantify the percentage of DSFGs that lie above the MS. Methods. We adopted a multi-wavelength approach with data from optical to submillimetre wavelengths from surveys at the North Ecliptic Pole to study a submillimetre sample of high-redshift galaxies. Two submillimetre selection methods were used, including: sources selected at 850 μm with the Sub-millimetre Common-User Bolometer Array 2) SCUBA-2 instrument and Herschel-Spectral and Photometric Imaging Receiver (SPIRE) selected sources (colour-colour diagrams and 500 μm risers), finding that 185 have good multi-wavelength coverage. The resulting sample of 185 high-z candidates was further studied by spectral energy distribution fitting with the CIGALE fitting code. We derived photometric redshifts, stellar masses, SFRs, and additional physical parameters, such as the infrared luminosity and active galactic nuclei (AGN) contribution. Results. We find that the Herschel-SPIRE selected DSFGs generally have higher redshifts (z = 2.57−0.09+0.08) than sources that are selected solely by the SCUBA-2 method (z = 1.45−0.06+0.21). We find moderate SFRs (797−50+108 M⊙ yr−1), which are typically lower than those found in other studies. We find that the different results in the literature are, only in part, due to selection effects, as even in the most extreme cases, SFRs are still lower than a few thousand solar masses per year. The difference in measured SFRs affects the position of DSFGs on the MS of galaxies; most of the DSFGs lie on the MS (60%). Finally, we find that the star formation efficiency (SFE) depends on the epoch and intensity of the star formation burst in the galaxy; the later the burst, the more intense the star formation. We discuss whether the higher SFEs in DSFGs could be due to mergers.

scholarly journals Towards a census of high-redshift dusty galaxies with Herschel

2018 ◽  
Vol 614 ◽  
pp. A33 ◽  
Author(s):  
D. Donevski ◽  
V. Buat ◽  
F. Boone ◽  
C. Pappalardo ◽  
M. Bethermin ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Far Infrared ◽  
Virgo Cluster ◽  
Spectral Energy ◽  
Distribution Fitting ◽  
Redshift Distribution ◽  
Star Forming

Context. Over the last decade a large number of dusty star-forming galaxies has been discovered up to redshift z = 2 − 3 and recent studies have attempted to push the highly confused Herschel SPIRE surveys beyond that distance. To search for z ≥ 4 galaxies they often consider the sources with fluxes rising from 250 μm to 500 μm (so-called “500 μm-risers”). Herschel surveys offer a unique opportunity to efficiently select a large number of these rare objects, and thus gain insight into the prodigious star-forming activity that takes place in the very distant Universe. Aims. We aim to implement a novel method to obtain a statistical sample of 500 μm-risers and fully evaluate our selection inspecting different models of galaxy evolution. Methods. We consider one of the largest and deepest Herschel surveys, the Herschel Virgo Cluster Survey. We develop a novel selection algorithm which links the source extraction and spectral energy distribution fitting. To fully quantify selection biases we make end-to-end simulations including clustering and lensing. Results. We select 133 500 μm-risers over 55 deg2, imposing the criteria: S500 > S350 > S250, S250 > 13.2 mJy and S500 > 30 mJy. Differential number counts are in fairly good agreement with models, displaying a better match than other existing samples. The estimated fraction of strongly lensed sources is 24+6-5% based on models. Conclusions. We present the faintest sample of 500 μm-risers down to S250 = 13.2 mJy. We show that noise and strong lensing have an important impact on measured counts and redshift distribution of selected sources. We estimate the flux-corrected star formation rate density at 4 < z < 5 with the 500 μm-risers and find it to be close to the total value measured in far-infrared. This indicates that colour selection is not a limiting effect to search for the most massive, dusty z > 4 sources.

scholarly journals Spectroscopy with the JWST Advanced Deep Extragalactic Survey (JADES) - the NIRSpec/NIRCAM GTO galaxy evolution project

2019 ◽  
Vol 15 (S352) ◽  
pp. 342-346
Author(s):  
Andrew J. Bunker
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Rest Frame ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Broad Band ◽  
Spectral Energy ◽  
Balmer Line ◽  
Chemical Abundances ◽  
Star Forming

AbstractI present an overview of the JWST Advanced Deep Extragalactic Survey (JADES), a joint program of the JWST/NIRCam and NIRSpec Guaranteed Time Observations (GTO) teams involving 950 hours of observation. We will target two well-studied fields with excellent supporting data (e.g., from HST-CANDELS): GOODS-North and South, including the Ultra Deep Field. The science goal of JADES is to chart galaxy evolution at z > 2, and potentially out to z > 10, using the rest-frame optical and near-IR though observations from ≍ 1–5μm. Multi-colour NIRCam imaging with 9 filters will enable photometric redshifts and the application of the Lyman break technique out to unprecedented distances. NIRSpec spectroscopy (with spectral resolving powers of R = 100, 1000 & 2700) will measure secure spectroscopic redshifts of the photometrically-selected population, as well as stellar continuum slopes in the UV rest-frame, and hence study the role of dust, stellar population age, and other effects. Measuring emission lines can constrain the dust extinction, star formation rates, metallicity, chemical abundances, ionization and excitation mechanism in high redshift galaxies. Coupling NIRCam and NIRSpec observations will determine stellar populations (age, star formation histories, abundances) of galaxies and provide the information to correct their broad-band spectral energy distribution for likely line contamination. Potentially we can search for signatures of Population III stars such as HeII. We can address the contribution of star-forming galaxies at z > 7 to reionization by determining the faint end slope of the luminosity function and investigating the escape fraction of ionizing photons by comparing the UV stellar continuum with the Balmer-line fluxes.

scholarly journals The high-redshift SFR–M* relation is sensitive to the employed star formation rate and stellar mass indicators: towards addressing the tension between observations and simulations

2020 ◽  
Vol 492 (4) ◽  
pp. 5592-5606 ◽  
Author(s):  
A Katsianis ◽  
V Gonzalez ◽  
D Barrientos ◽  
X Yang ◽  
C D P Lagos ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Stellar Mass ◽  
Spectral Energy ◽  
Distribution Fitting ◽  
Star Forming ◽  
Stellar Masses

ABSTRACT There is a severe tension between the observed star formation rate (SFR)–stellar mass (M⋆) relations reported by different authors at z = 1–4. In addition, the observations have not been successfully reproduced by state-of-the-art cosmological simulations that tend to predict a factor of 2–4 smaller SFRs at a fixed M⋆. We examine the evolution of the SFR–M⋆ relation of z = 1–4 galaxies using the skirt simulated spectral energy distributions of galaxies sampled from the Evolution and Assembly of GaLaxies and their Environments simulations. We derive SFRs and stellar masses by mimicking different observational techniques. We find that the tension between observed and simulated SFR–M⋆ relations is largely alleviated if similar methods are used to infer the galaxy properties. We find that relations relying on infrared wavelengths (e.g. 24 ${\rm \, \mu m}$, MIPS – 24, 70, and 160 ${\rm \, \mu m}$ or SPIRE – 250, 350, and 500 ${\rm \, \mu m}$) have SFRs that exceed the intrinsic relation by 0.5 dex. Relations that rely on the spectral energy distribution fitting technique underpredict the SFRs at a fixed stellar mass by −0.5 dex at z ∼ 4 but overpredict the measurements by 0.3 dex at z ∼ 1. Relations relying on dust-corrected rest-frame ultraviolet luminosities, are flatter since they overpredict/underpredict SFRs for low/high star-forming objects and yield deviations from the intrinsic relation from 0.10 to −0.13 dex at z ∼ 4. We suggest that the severe tension between different observational studies can be broadly explained by the fact that different groups employ different techniques to infer their SFRs.

scholarly journals The effects of star formation history in the SFR–M* relation of H ii galaxies

2020 ◽  
Vol 500 (3) ◽  
pp. 3240-3253
Author(s):  
Amanda R Lopes ◽  
Eduardo Telles ◽  
Jorge Melnick
Keyword(s):  
Star Formation ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Star Formation History ◽  
Spectral Energy ◽  
Distribution Fitting ◽  
Good Tool ◽  
Star Forming ◽  
Additional Information ◽  
Star Formation Histories

ABSTRACT We discuss the implications of assuming different star formation histories (SFH) in the relation between star formation rate (SFR) and mass derived by the spectral energy distribution fitting (SED). Our analysis focuses on a sample of H ii galaxies, dwarf starburst galaxies spectroscopically selected through their strong narrow emission lines in SDSS DR13 at z &lt; 0.4, cross-matched with photometric catalogues from GALEX, SDSS, UKIDSS, and WISE. We modelled and fitted the SEDs with the code CIGALE adopting different descriptions of SFH. By adding information from different independent studies, we find that H ii galaxies are best described by episodic SFHs including an old (10 Gyr), an intermediate age (100−1000 Myr) and a recent population with ages &lt; 10 Myr. H ii galaxies agree with the SFR−M* relation from local star-forming galaxies, and only lie above such relation when the current SFR is adopted as opposed to the average over the entire SFH. The SFR−M* demonstrated not to be a good tool to provide additional information about the SFH of H ii galaxies, as different SFH present a similar behaviour with a spread of &lt;0.1 dex.

scholarly journals Serendipitous discovery of an “ALMA-only” galaxy at 5 < z < 6 in an ALMA 3-mm survey

2019 ◽  
Vol 15 (S352) ◽  
pp. 194-198
Author(s):  
Christina C. Williams
Keyword(s):  
Star Formation ◽  
Energy Distribution ◽  
Star Formation Rate ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Spectral Energy ◽  
Large Contribution ◽  
Massive Galaxies ◽  
Multi Wavelength

AbstractWe discuss the serendipitous discovery of a dusty high-redshift galaxy in a small (8 arcmin2) ALMA 3-mm survey Williams et al. (2019). The galaxy was previously unknown and is absent from existing multi-wavelength catalogs (“ALMA-only”). Using the ALMA position as prior, we perform forced deblended photometry to constrain its spectral energy distribution. The spectral energy distribution is well described by a massive (M* = 1010.8 M⊙) and highly obscured (AV ∼ 4) galaxy at redshift z = 5.5 ± 1.1 with star formation rate ∼ 300 M⊙yr−1. Our small survey area implies an uncertain but large contribution to the cosmic star formation rate density, similar to the contribution from all ultraviolet-selected galaxies combined at this redshift. This galaxy likely traces an abundant population of massive galaxies absent from current samples of infrared-selected or sub-millimeter galaxies, but with larger space densities, higher duty cycles, and significant contribution to the cosmic star-formation rate and stellar mass densities.

scholarly journals SUPER

2018 ◽  
Vol 620 ◽  
pp. A82 ◽  
Author(s):  
C. Circosta ◽  
V. Mainieri ◽  
P. Padovani ◽  
G. Lanzuisi ◽  
M. Salvato ◽  
...  
Keyword(s):  
Star Formation ◽  
Adaptive Optics ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Host Galaxy ◽  
Spectral Energy ◽  
Distribution Fitting ◽  
X Ray ◽  
Narrow Component ◽  
The Impact

Theoretical models of galaxy formation suggest that the presence of an active galactic nucleus (AGN) is required to regulate the growth of its host galaxy through feedback mechanisms, produced by, for example, AGN-driven outflows. Although many observational studies have revealed that such outflows are common both at low and high redshift, a comprehensive picture is still missing. In particular, the peak epoch of galaxy assembly (1 <  z <  3) has been poorly explored so far, and current observations in this redshift range are mostly limited to targets with high chances to be in an outflowing phase. This paper introduces SUPER (a SINFONI Survey for Unveiling the Physics and Effect of Radiative feedback), an ongoing ESO’s VLT/SINFONI Large Programme. SUPER will perform the first systematic investigation of ionized outflows in a sizeable and blindly-selected sample of 39 X-ray AGN at z ∼ 2, which reaches high spatial resolutions (∼2 kpc) thanks to the adaptive optics-assisted IFS observations. The outflow morphology and star formation in the host galaxy will be mapped through the broad component of [O III]λ5007 and the narrow component of Hα emission lines. The main aim of our survey is to infer the impact of outflows on the on-going star formation and to link the outflow properties to a number of AGN and host galaxy properties. We describe here the survey characteristics and goals, as well as the selection of the target sample. Moreover, we present a full characterization of its multi-wavelength properties: we measure, via spectral energy distribution fitting of UV-to-FIR photometry, stellar masses (4 × 109 − 2 × 1011 M⊙), star formation rates (25 − 680 M⊙ yr−1) and AGN bolometric luminosities (2 × 1044 − 8 × 1047 erg s−1), along with obscuring column densities (up to 2 × 1024 cm−2) and luminosities in the hard 2 − 10 keV band (2 × 1043 − 6 × 1045 erg s−1) derived through X-ray spectral analysis. Finally, we classify our AGN as jetted or non-jetted according to their radio and FIR emission.

scholarly journals Multiwavelength dissection of a massive heavily dust-obscured galaxy and its blue companion at z∼2

2021 ◽  
Vol 646 ◽  
pp. A127
Author(s):  
M. Hamed ◽  
L. Ciesla ◽  
M. Béthermin ◽  
K. Małek ◽  
E. Daddi ◽  
...  
Keyword(s):  
Star Formation ◽  
Spectral Energy Distribution ◽  
Gas Content ◽  
Spectral Energy ◽  
Physical Parameters ◽  
Molecular Gas ◽  
Star Forming ◽  
Attenuation Law ◽  
Star Formation Activity ◽  
Attenuation Laws

Aims. We study a system of two galaxies, Astarte and Adonis, at z ∼ 2. At this time, the Universe was undergoing the peak of its star formation activity. Astarte is a dusty star-forming galaxy at the massive end of the main sequence (MS), and Adonis is a less massive companion galaxy that is bright in the ultraviolet and has an optical spectroscopic redshift. We investigate whether this ultramassive galaxy is quenching, and whether it has always been on the MS of star-forming galaxies. Methods. We used the code CIGALE to model the spectral energy distribution. The code relies on the energetic balance between the ultraviolet and the infrared. We derived some of the key physical properties of Astarte and Adonis, mainly their star formation rates (SFRs), stellar masses, and dust luminosities. We inspected the variation of the physical parameters depending on the assumed dust-attenuation law. We also estimated the molecular gas mass of Astarte from its CO emission, using different αCO and transition ratios (r31), and we discuss the implication of the various assumptions on the gas-mass derivation. Reults. We find that Astarte exhibits a MS-like star formation activity, and Adonis is undergoing a strong starburst phase. The molecular gas mass of Astarte is far lower than the gas fraction of typical star-forming galaxies at z = 2. This low gas content and high SFR result in a depletion time of 0.22 ± 0.07 Gyr, which is slightly shorter than expected for a MS galaxy at this redshift. The CO luminosity relative to the total infrared luminosity suggests a MS-like activity when we assume a galactic conversion factor and a low transition ratio. The SFR of Astarte is on the same order when different attenuation laws are used, unlike its stellar mass, which increases when shallow attenuation laws are used (∼1 × 1011 M⊙ assuming a Calzetti relation, versus ∼4 × 1011 M⊙ assuming a shallow attenuation law). We discuss these properties and suggest that Astarte might be experiencing a recent decrease in star formation activity and is quenching through the MS following a starburst epoch.

scholarly journals SCUBA-2 observations of candidate starbursting protoclusters selected by Planck and Herschel-SPIRE

2019 ◽  
Vol 490 (3) ◽  
pp. 3840-3859 ◽  
Author(s):  
T Cheng ◽  
D L Clements ◽  
J Greenslade ◽  
J Cairns ◽  
P Andreani ◽  
...  
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Spectral Energy ◽  
Cumulative Number ◽  
Redshift Distribution ◽  
Photometric Redshifts ◽  
Star Forming ◽  
Photometric Redshift

ABSTRACT We present SCUBA-2 850 $\mathrm{ \mu}$m observations of 13 candidate starbursting protoclusters selected using Planck and Herschel data. The cumulative number counts of the 850 $\mathrm{ \mu}$m sources in 9 of 13 of these candidate protoclusters show significant overdensities compared to the field, with the probability &lt;10−2 assuming the sources are randomly distributed in the sky. Using the 250, 350, 500, and 850 $\mathrm{ \mu}$m flux densities, we estimate the photometric redshifts of individual SCUBA-2 sources by fitting spectral energy distribution templates with an MCMC method. The photometric redshift distribution, peaking at 2 &lt; z &lt; 3, is consistent with that of known z &gt; 2 protoclusters and the peak of the cosmic star formation rate density (SFRD). We find that the 850 $\mathrm{ \mu}$m sources in our candidate protoclusters have infrared luminosities of $L_{\mathrm{IR}}\gtrsim 10^{12}\, \mathrm{L}_{\odot }$ and star formation rates of SFR  = (500–1500) M⊙ yr−1. By comparing with results in the literature considering only Herschel photometry, we conclude that our 13 candidate protoclusters can be categorized into four groups: six of them being high-redshift starbursting protoclusters, one being a lower redshift cluster or protocluster, three being protoclusters that contain lensed dusty star-forming galaxies or are rich in 850 $\mathrm{ \mu}$m sources, and three regions without significant Herschel or SCUBA-2 source overdensities. The total SFRs of the candidate protoclusters are found to be comparable or higher than those of known protoclusters, suggesting our sample contains some of the most extreme protocluster population. We infer that cross-matching Planck and Herschel data is a robust method for selecting candidate protoclusters with overdensities of 850 $\mathrm{ \mu}$m sources.

scholarly journals The VLA-COSMOS 3 GHz Large Project: Star formation properties and radio luminosity functions of AGN with moderate-to-high radiative luminosities out to z∼ 6

2018 ◽  
Vol 620 ◽  
pp. A192 ◽  
Author(s):  
L. Ceraj ◽  
V. Smolčić ◽  
I. Delvecchio ◽  
M. Novak ◽  
G. Zamorani ◽  
...  
Keyword(s):  
Star Formation ◽  
Radio Emission ◽  
Spectral Energy Distribution ◽  
Galactic Nuclei ◽  
Spectral Energy ◽  
Distribution Fitting ◽  
Star Forming ◽  
Luminosity Functions ◽  
Large Project ◽  
Analytic Models

We have studied a sample of 1604 moderate-to-high radiative luminosity active galactic nuclei (HLAGN) selected at 3 GHz within the VLA-COSMOS 3 GHz Large Project. These were classified by combining multiple AGN diagnostics: X-ray data, mid-infrared data and broadband spectral energy distribution fitting. We decomposed the total radio 1.4 GHz luminosity (L1.4 GHz, TOT) into the emission originating from star formation and AGN activity by measuring the excess in L1.4 GHz, TOT relative to the infrared-radio correlation of star-forming galaxies. To quantify the excess, for each source we calculated the AGN fraction (fAGN) defined as the fractional contribution of AGN activity to L1.4 GHz, TOT. The majority of the HLAGN, (68.0 ± 1.5)%, are dominated by star-forming processes (fAGN ≤ 0.5), while (32.0 ± 1.5)% are dominated by AGN-related radio emission (0.5 <  fAGN ≤ 1). We used the AGN-related 1.4 GHz emission to derive the 1.4 GHz AGN luminosity functions of HLAGN. By assuming pure density and pure luminosity evolution models we constrained their cosmic evolution out to z ∼ 6, finding Φ*(z)∝(1 + z)(2.64 ± 0.10)+(−0.61 ± 0.04)z and L*(z)∝(1 + z)(3.97 ± 0.15)+(−0.92 ± 0.06)z. These evolutionary laws show that the number and luminosity density of HLAGN increased from higher redshifts (z ∼ 6) up to a maximum in the redshift range 1 <  z <  2.5, followed by a decline toward local values. By scaling the 1.4 GHz AGN luminosity to kinetic luminosity using the standard conversion, we estimate the kinetic luminosity density as a function of redshift. We compare our result to the semi-analytic models of radio mode feedback, and find that this feedback could have played an important role in the context of AGN-host co-evolution in HLAGN which shows evidence of AGN-related radio emission (fAGN >  0).

scholarly journals Extinction-free Census of AGNs in the AKARI/IRC North Ecliptic Pole Field from 23-band infrared photometry from Space Telescopes

2020 ◽  
Vol 499 (3) ◽  
pp. 4068-4081 ◽  
Author(s):  
Ting-Wen Wang ◽  
Tomotsugu Goto ◽  
Seong Jin Kim ◽  
Tetsuya Hashimoto ◽  
Denis Burgarella ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Cosmic Time ◽  
Spectral Energy ◽  
Wide Field ◽  
Space Telescopes ◽  
Distribution Modelling ◽  
Star Forming ◽  
The North ◽  
Band Filter ◽  
Infrared Survey

ABSTRACT In order to understand the interaction between the central black hole and the whole galaxy or their co-evolution history along with cosmic time, a complete census of active galactic nucleus (AGN) is crucial. However, AGNs are often missed in optical, UV, and soft X-ray observations since they could be obscured by gas and dust. A mid-infrared (MIR) survey supported by multiwavelength data is one of the best ways to find obscured AGN activities because it suffers less from extinction. Previous large IR photometric surveys, e.g. Wide field Infrared Survey Explorer and Spitzer, have gaps between the MIR filters. Therefore, star-forming galaxy-AGN diagnostics in the MIR were limited. The AKARI satellite has a unique continuous nine-band filter coverage in the near to MIR wavelengths. In this work, we take advantage of the state-of-the-art spectral energy distribution modelling software, cigale, to find AGNs in MIR. We found 126 AGNs in the North Ecliptic Pole-Wide field with this method. We also investigate the energy released from the AGN as a fraction of the total IR luminosity of a galaxy. We found that the AGN contribution is larger at higher redshifts for a given IR luminosity. With the upcoming deep IR surveys, e.g. JWST, we expect to find more AGNs with our method.

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