scholarly journals Large High Redshift Spectroscopic Surveys

2010 ◽  
Vol 6 (S277) ◽  
pp. 121-127
Author(s):  
Olivier Le Fèvre
Keyword(s):  
Galaxy Evolution ◽  
Mass Density ◽  
High Redshift ◽  
Sample Selection ◽  
Global Perspective ◽  
Observational Cosmology ◽  
Wide Field ◽  
Redshift Distribution ◽  
Redshift Surveys ◽  
Mass Assembly

AbstractDeep spectroscopic redshift surveys have become an important tool for observational cosmology, supported by a new generation of wide field multi-object spectrographs. They bring high redshift accuracy and a wealth of spectral features necessary for precision astrophysics and have led to the outstanding progress in our understanding of the different phases of galaxy evolution. The measurement of the evolution of volume quantities like the luminosity and mass functions or the correlation function, has enabled a deep insight into galaxy evolution since redshifts z ≃ 7. The redshift distribution N(z,m) is a basic property but is still difficult to be reproduced by models. We have now a global perspective on the history of star formation with a peak at z = 1−2 but the decline in SFRD at higher redshifts is still to be confirmed. The evolution of the stellar mass density with a fast growth in red passive galaxies between z = 2 and z = 1 is well established. The contribution to galaxy mass assembly of key physical processes like merging or cold accretion is now well documented. However, the pioneer measurements at the high redshift end z > > 1 remain to be consolidated with robust sample selection and statistical accuracy from large spectroscopic redshift surveys, a challenge for the years to come.

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 The 2Mass Redshift Survey

1998 ◽  
Vol 11 (1) ◽  
pp. 487-491
Author(s):  
J. Huchra ◽  
E. Tollestrup ◽  
S. Schneider ◽  
M. Skrutski ◽  
T. Jarrett ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Large Scale ◽  
Background Radiation ◽  
Local Density ◽  
Mass Density ◽  
High Redshift ◽  
Density Field ◽  
Observational Cosmology ◽  
Microwave Background ◽  
Flow Measurements

With the current convergence of determinations of the Hubble Constant (e.g. The Extragalactic Distance Scale, 1997, Livio, Donahue and Panagia, eds.) to values within ±25% rather than a factor of two, and the clear possibility of determining q0 using high redshift supernovae (Garnavich et al. 1998), the major remaining problem in observational cosmology is the determination of Ω — what is the dark matter, how much is there, and how is it distributed? The most direct approach to the last two parts of the question has been to study galaxy dynamics, first through the motions of galaxies in binaries, groups and clusters, and in the last decade and a half, driven by the observation of our motion w.r.t. the Cosmic Microwave Background (CMB) and thenotion that DM must be clumped on larger scales than galaxy clusters if (Ω is to be unity, through the study of large scale galaxy flows. The ratio of the mass density to the closure mass density, Ω, is thought by most observers to be ~0.1-0.3, primarily based on the results of dynamical measurements of galaxy clusters and, more recently, gravitational lensing studies of clusters. In contrast, most theoretical cosmologists opt for a high density universe, Ω = 1.0, based on the precepts of the inflation scenario, the difficulty of forming galaxies in low density models given the observed smoothness of the microwave background radiation, and the observational evidence from the matching of the available large scale flow measurements (and the absolute microwave background dipole velocity) to the local density field. However this last result is extremely controversial—matching the velocity field to the density field derived from IRAS (60μ) selected galaxy samples yields high Ω values (e.g., Dekel et al. 1993) but matching to optically selected samples yields low values (Hudson 1994; Lahav et al. 1994; Santiago et al. 1995). On small scales, the high Ω camp argues that the true matter distribution is much more extended than the distribution of galaxies, so the dynamical mass estimates are biased low.

scholarly journals Compact galaxies and the size–mass galaxy distribution from a colour-selected sample at 0.04 < z < 0.15 supplemented by ugrizYJHK photometric redshifts

2020 ◽  
Vol 500 (2) ◽  
pp. 1557-1574
Author(s):  
Ivan K Baldry ◽  
Tricia Sullivan ◽  
Raffaele Rani ◽  
Sebastian Turner
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Sample Selection ◽  
Distribution Functions ◽  
Sloan Digital Sky Survey ◽  
Photometric Redshifts ◽  
Galaxy Distribution ◽  
Sky Survey ◽  
Galaxy Sample ◽  
Compact Galaxies

ABSTRACT The size–mass galaxy distribution is a key diagnostic for galaxy evolution. Massive compact galaxies are potential surviving relics of a high-redshift phase of star formation. Some of these could be nearly unresolved in Sloan Digital Sky Survey (SDSS) imaging and thus not included in galaxy samples. To overcome this, a sample was selected from the combination of SDSS and UKIRT Infrared Deep Sky Survey (UKIDSS) photometry to r &lt; 17.8. This was done using colour–colour selection, and then by obtaining accurate photometric redshifts (photo-z) using scaled flux matching (SFM). Compared to spectroscopic redshifts (spec-z), SFM obtained a 1σ scatter of 0.0125 with only 0.3 per cent outliers (|Δln (1 + z)| &gt; 0.06). A sample of 163 186 galaxies was obtained with 0.04 &lt; z &lt; 0.15 over $2300\, {\rm deg}^2$ using a combination of spec-z and photo-z. Following Barro et al. log Σ1.5 = log M* − 1.5log r50, maj was used to define compactness. The spectroscopic completeness was 76 per cent for compact galaxies (log Σ1.5 &gt; 10.5) compared to 92 per cent for normal-sized galaxies. This difference is primarily attributed to SDSS ‘fibre collisions’ and not the completeness of the main galaxy sample selection. Using environmental overdensities, this confirms that compact quiescent galaxies are significantly more likely to be found in high-density environments compared to normal-sized galaxies. By comparison with a high-redshift sample from 3D-HST, log Σ1.5 distribution functions show significant evolution, with this being a compelling way to compare with simulations such as EAGLE. The number density of compact quiescent galaxies drops by a factor of about 30 from z ∼ 2 to log (n/Mpc−3) = − 5.3 ± 0.4 in the SDSS–UKIDSS sample. The uncertainty is dominated by the steep cut off in log Σ1.5, which is demonstrated conclusively using this complete sample.

scholarly journals Evolution of dwarf galaxy observable parameters

2020 ◽  
Vol 493 (1) ◽  
pp. 638-650
Author(s):  
Eimantas Ledinauskas ◽  
Kastytis Zubovas
Keyword(s):  
Galaxy Evolution ◽  
Dwarf Galaxies ◽  
Background Radiation ◽  
Dwarf Galaxy ◽  
High Redshift ◽  
Stellar Mass ◽  
Local Universe ◽  
Isolated Galaxies ◽  
Mass Assembly ◽  
Hubble Time

ABSTRACT We present a semi-analytic model of isolated dwarf galaxy evolution and use it to study the build-up of observed correlations between dwarf galaxy properties. We analyse the evolution using models with averaged and individual halo mass assembly histories in order to determine the importance of stochasticity on the present-day properties of dwarf galaxies. The model has a few free parameters, but when these are calibrated using the halo mass–stellar mass and stellar mass–metallicity relations, the results agree with other observed dwarf galaxy properties remarkably well. Redshift evolution shows that even isolated galaxies change significantly over the Hubble time and that ‘fossil dwarf galaxies’ with properties equivalent to those of high-redshift analogues should be extremely rare, or non-existent, in the local Universe. A break in most galaxy property correlations develops over time, at a stellar mass $M_* \simeq 10^7 \, {\rm M_{\odot }}$. It is caused predominantly by the ionizing background radiation and can therefore in principle be used to constrain the properties of reionization.

scholarly journals Lyα Forest Tomography of the z > 2 Cosmic Web

2014 ◽  
Vol 11 (S308) ◽  
pp. 360-363
Author(s):  
Khee-Gan Lee
Keyword(s):  
Galaxy Evolution ◽  
Large Scale ◽  
High Redshift ◽  
Large Scale Structure ◽  
Area Density ◽  
Star Forming ◽  
Redshift Surveys ◽  
High Area ◽  
Galaxy Redshift ◽  
Large Telescopes

AbstractThe hydrogen Lyα forest is an important probe of the z > 2 Universe that is otherwise challenging to observe with galaxy redshift surveys, but this technique has traditionally been limited to 1D studies in front of bright quasars. However, by pushing to faint magnitudes (g > 23) with 8-10m large telescopes it becomes possible to exploit the high area density of high-redshift star-forming galaxies to create 3D tomographic maps of large-scale structure in the foreground. I describe the first pilot observations using this technique, as well discuss future surveys and the resulting science possibilities for galaxy evolution and cosmology.

scholarly journals Galaxy Metabolism

2010 ◽  
Vol 27 (3) ◽  
pp. 233-233
Author(s):  
Andrew Hopkins
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Mass Density ◽  
High Redshift ◽  
Large Population ◽  
Star Formation History ◽  
Global Constraints ◽  
Great Success ◽  
Mass Dependent ◽  
Cosmic History

‘Galaxy Metabolism' was the second in the annual ‘Southern Cross Astrophysics Conference Series’ (http://www.aao.gov.au/AAO/southerncross/), supported by the Anglo-Australian Observatory and the Australia Telescope National Facility. It was held at the Australian National Maritime Museum in Darling Harbour, Sydney, from 22 to 26 June 2009, and was attended by 91 delegates from around the world.Over the past decade, both the star formation history and stellar mass density in galaxies spanning most of cosmic history have been well constrained. This provides the backdrop and framework within which many detailed investigations of galaxy growth are now placed. The mass-dependent and environment-dependent evolution of galaxies over cosmic history is now the focus of several surveys. Many studies are also exploring the role of gas infall and outflow in driving galaxy evolution, and the connection of these processes to massive star formation within galaxies.The aims of ‘Galaxy Metabolism’ were to bring together the global constraints on galaxy evolution, at both low and high redshift, with detailed studies of well-resolved systems, to define a clear picture of our understanding of galaxy metabolism: How do the processes of ingestion (infall), digestion (ISM physics, star formation) and excretion (outflow) govern the global properties of galaxies; how do these change over a galaxy's lifetime; and are the constraints from nearby well resolved studies consistent with those from large population surveys at low and high redshift?The conference was a great success, with an extensive variety of topics covered spanning many aspects of galaxy evolution, and brought together eloquently in a comprehensive conference summary by Warrick Couch. The four papers by De Lucia (2010), Cole (2010), Vlajić (2010) and Stocke et al. (2010) presented in this special collection of PASA are just a sampling of the depth and variety of the resentations given during the conference.

scholarly journals Deep-CEE I: fishing for galaxy clusters with deep neural nets

2019 ◽  
Vol 490 (4) ◽  
pp. 5770-5787 ◽  
Author(s):  
Matthew C Chan ◽  
John P Stott
Keyword(s):  
Deep Learning ◽  
Galaxy Clusters ◽  
Galaxy Evolution ◽  
Learning Algorithm ◽  
High Redshift ◽  
Simulated Data ◽  
Galaxy Cluster ◽  
Neural Nets ◽  
Training Data ◽  
Wide Field

ABSTRACT We introduce Deep-CEE (Deep Learning for Galaxy Cluster Extraction and Evaluation), a proof of concept for a novel deep learning technique, applied directly to wide-field colour imaging to search for galaxy clusters, without the need for photometric catalogues. This technique is complementary to traditional methods and could also be used in combination with them to confirm existing galaxy cluster candidates. We use a state-of-the-art probabilistic algorithm, adapted to localize and classify galaxy clusters from other astronomical objects in Sloan Digital Sky Survey imaging. As there is an abundance of labelled data for galaxy clusters from previous classifications in publicly available catalogues, we do not need to rely on simulated data. This means we keep our training data as realistic as possible, which is advantageous when training a deep learning algorithm. Ultimately, we will apply our model to surveys such as Large Synoptic Survey Telescope and Euclid to probe wider and deeper into unexplored regions of the Universe. This will produce large samples of both high-redshift and low-mass clusters, which can be utilized to constrain both environment-driven galaxy evolution and cosmology.

scholarly journals The VANDELS ESO public spectroscopic survey: Observations and first data release

2018 ◽  
Vol 616 ◽  
pp. A174 ◽  
Author(s):  
L. Pentericci ◽  
R. J. McLure ◽  
B. Garilli ◽  
O. Cucciati ◽  
P. Franzetti ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Spectroscopic Data ◽  
Signal To Noise Ratio ◽  
High Redshift ◽  
Measurement Procedure ◽  
Integration Time ◽  
High Signal ◽  
Redshift Distribution ◽  
Data Set ◽  
Data Release

This paper describes the observations and the first data release (DR1) of the ESO public spectroscopic survey “VANDELS, a deep VIMOS survey of the CANDELS CDFS and UDS fields”. The main targets of VANDELS are star-forming galaxies at redshift 2.4 < z < 5.5, an epoch when the Universe had not yet reached 20% of its current age, and massive passive galaxies in the range 1 < z < 2.5. By adopting a strategy of ultra-long exposure times, ranging from a minimum of 20 h to a maximum of 80 h per source, VANDELS is specifically designed to be the deepest-ever spectroscopic survey of the high-redshift Universe. Exploiting the red sensitivity of the refurbished VIMOS spectrograph, the survey is obtaining ultra-deep optical spectroscopy covering the wavelength range 4800–10 000 Å with a sufficiently high signal-to-noise ratio to investigate the astrophysics of high-redshift galaxy evolution via detailed absorption line studies of well-defined samples of high-redshift galaxies. VANDELS-DR1 is the release of all medium-resolution spectroscopic data obtained during the first season of observations, on a 0.2 square degree area centered around the CANDELS-CDFS (Chandra deep-field south) and CANDELS-UDS (ultra-deep survey) areas. It includes data for all galaxies for which the total (or half of the total) scheduled integration time was completed. The DR1 contains 879 individual objects, approximately half in each of the two fields, that have a measured redshift, with the highest reliable redshifts reaching zspec ~ 6. In DR1 we include fully wavelength-calibrated and flux-calibrated 1D spectra, the associated error spectrum and sky spectrum, and the associated wavelength-calibrated 2D spectra. We also provide a catalog with the essential galaxy parameters, including spectroscopic redshifts and redshift quality flags measured by the collaboration. We present the survey layout and observations, the data reduction and redshift measurement procedure, and the general properties of the VANDELS-DR1 sample. In particular, we discuss the spectroscopic redshift distribution and the accuracy of the photometricredshifts for each individual target category, and we provide some examples of data products for the various target typesand the different quality flags. All VANDELS-DR1 data are publicly available and can be retrieved from the ESO archive. Two further data releases are foreseen in the next two years, and a final data release is currently scheduled for June 2020, which will include an improved rereduction of the entire spectroscopic data set.

scholarly journals Space Project for Astrophysical and Cosmological Exploration (SPACE), an ESA stand-alone mission and a possible contribution to the Origins Space Telescope

2021 ◽  
Author(s):  
Denis Burgarella ◽  
Andrew Bunker ◽  
Rychard Bouwens ◽  
Laurent Pagani ◽  
Jose Afonso ◽  
...  
Keyword(s):  
Black Holes ◽  
Galaxy Evolution ◽  
High Redshift ◽  
Cosmic Time ◽  
Wide Field ◽  
Unique Region ◽  
Space Telescope ◽  
Near Ir ◽  
Space Project ◽  
First Galaxies

AbstractWe propose a new mission called Space Project for Astrophysical and Cosmological Exploration (SPACE) as part of the ESA long term planning Voyage 2050 programme. SPACE will study galaxy evolution at the earliest times, with the key goals of charting the formation of the heavy elements, measuring the evolution of the galaxy luminosity function, tracing the build-up of stellar mass in galaxies over cosmic time, and finding the first super-massive black holes (SMBHs) to form. The mission will exploit a unique region of the parameter space, between the narrow ultra-deep surveys with HST and JWST, and shallow wide-field surveys such as the Roman Space Telescope and EUCLID, and should yield by far the largest sample of any current or planned mission of very high redshift galaxies at z > 10 which are sufficiently bright for detailed follow-up spectroscopy. Crucially, we propose a wide-field spectroscopic near-IR + mid-IR capability which will greatly enhance our understanding of the first galaxies by detecting and identifying a statistical sample of the first galaxies and the first supermassive black holes, and to chart the metal enrichment history of galaxies in the early Universe – potentially finding signatures of the very first stars to form from metal-free primordial gas. The wide-field and wavelength range of SPACE will also provide us a unique opportunity to study star formation by performing a wide survey of the Milky Way in the near-IR + mid-IR. This science project can be enabled either by a stand-alone ESA-led M mission or by an instrument for an L mission (with ESA and/or NASA, JAXA and other international space agencies) with a wide-field (sub-)millimetre capability at λ > 500 μm.

scholarly journals Star Formation in CALIFA survey perturbed galaxies. II. Star Formation Histories and Oxygen Abundances

2021 ◽  
Author(s):  
A Morales-Vargas ◽  
J P Torres-Papaqui ◽  
F F Rosales-Ortega ◽  
M Chow-Martínez ◽  
J J Trejo-Alonso ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Mass Density ◽  
Stellar Mass ◽  
Mass Rate ◽  
Star Forming ◽  
Star Forming Regions ◽  
Stellar Feedback ◽  
Tidal Interactions ◽  
Mass Assembly

Abstract Galaxy evolution is generally affected by tidal interactions. Firstly, in this series, we reported several effects which suggest that tidal interactions contribute to regulating star formation (SF). To confirm that so, we now compare stellar mass assembly histories and SF look-back time annular profiles between CALIFA survey tidally and non-tidally perturbed galaxies. We pair their respective star-forming regions at the closest stellar mass surface densities to reduce the influence of stellar mass. The assembly histories and annular profiles show statistically significant differences so that higher star formation rates characterize regions in tidally perturbed galaxies. These regions underwent a more intense (re)activation of SF in the last 1 Gyr. Varying shapes of the annular profiles also reflect fluctuations between suppression and (re)activation of SF. Since gas-phase abundances use to be lower in more actively than in less actively star-forming galaxies, we further explore the plausible presence of metal-poor gas inflows able to dilute such abundances. The resolved relations of oxygen (O) abundance, with stellar mass density and with total gas fraction, show slightly lower O abundances for regions in tidally perturbed galaxies. The single distributions of O abundances statistically validate that so. Moreover, from a metallicity model based on stellar feedback, the mass rate differentials (inflows−outflows) show statistically valid higher values for regions in tidally perturbed galaxies. These differentials, and the metal fractions from the population synthesis, suggest dominant gas inflows in these galaxies. This dominance, and the differences in SF through time, confirm the previously reported effects of tidal interactions on SF.

Sign in / Sign up

Export Citation Format

Share Document