scholarly journals The IRX–β relation of high-redshift galaxies

2021 ◽  
Vol 502 (3) ◽  
pp. 3210-3241
Author(s):  
Lichen Liang ◽  
Robert Feldmann ◽  
Christopher C Hayward ◽  
Desika Narayanan ◽  
Onur Çatmabacak ◽  
...  
Keyword(s):  
Optical Depth ◽  
High Redshift ◽  
Spectral Slope ◽  
Infrared Excess ◽  
High Redshift Galaxies ◽  
Dust Extinction ◽  
Tightly Coupled ◽  
Nearby Galaxies ◽  
Metal Ratio ◽  
Stellar Properties

ABSTRACT The relation between infrared excess (IRX) and UV spectral slope (βUV) is an empirical probe of dust properties of galaxies. The shape, scatter, and redshift evolution of this relation are not well understood, however, leading to uncertainties in estimating the dust content and star formation rates (SFRs) of galaxies at high redshift. In this study, we explore the nature and properties of the IRX–βUV relation with a sample of z = 2–6 galaxies ($M_*\approx 10^9\!-\!10^{12}\, \mathrm{M}_\odot$) extracted from high-resolution cosmological simulations (MassiveFIRE) of the Feedback in Realistic Environments (FIRE) project. The galaxies in our sample show an IRX–βUV relation that is in good agreement with the observed relation in nearby galaxies. IRX is tightly coupled to the UV optical depth, and is mainly determined by the dust-to-star geometry instead of total dust mass, while βUV is set both by stellar properties, UV optical depth, and the dust extinction law. Overall, much of the scatter in the IRX–βUV relation of our sample is found to be driven by variations of the intrinsic UV spectral slope. We further assess how the IRX–βUV relation depends on viewing direction, dust-to-metal ratio, birth-cloud structures, and the dust extinction law and we present a simple model that encapsulates most of the found dependencies. Consequently, we argue that the reported ‘deficit’ of the infrared/sub-millimetre bright objects at z ≳ 5 does not necessarily imply a non-standard dust extinction law at those epochs.

scholarly journals Extremely metal-poor galaxies with HST/COS: laboratories for models of low-metallicity massive stars and high-redshift galaxies

2019 ◽  
Vol 488 (3) ◽  
pp. 3492-3506 ◽  
Author(s):  
Peter Senchyna ◽  
Daniel P Stark ◽  
Jacopo Chevallard ◽  
Stéphane Charlot ◽  
Tucker Jones ◽  
...  
Keyword(s):  
Massive Stars ◽  
High Redshift ◽  
Formation Rate ◽  
Uv Spectra ◽  
High Redshift Galaxies ◽  
Star Forming ◽  
High Ionization ◽  
Moderate Resolution ◽  
Low Metallicity ◽  
Nearby Galaxies

Abstract Ultraviolet (UV) observations of local star-forming galaxies have begun to establish an empirical baseline for interpreting the rest-UV spectra of reionization-era galaxies. However, existing high-ionization emission line measurements at z > 6 ($\rm W_{C\, {\scriptscriptstyle IV},0}{} \gtrsim 20$ Å) are uniformly stronger than observed locally ($\rm W_{C\, {\scriptscriptstyle IV},0}{} \lesssim 2$ Å), likely due to the relatively high metallicities (Z/Z$\odot$ > 0.1) typically probed by UV surveys of nearby galaxies. We present new HST/COS spectra of six nearby (z < 0.01) extremely metal-poor galaxies (XMPs, Z/Z$\odot$ ≲ 0.1) targeted to address this limitation and provide constraints on the highly uncertain ionizing spectra powered by low-metallicity massive stars. Our data reveal a range of spectral features, including one of the most prominent nebular C iv doublets yet observed in local star-forming systems and strong He ii emission. Using all published UV observations of local XMPs to date, we find that nebular C iv emission is ubiquitous in very high specific star formation rate systems at low metallicity, but still find equivalent widths smaller than those measured in individual lensed systems at z > 6. Our moderate-resolution HST/COS data allow us to conduct an analysis of the stellar winds in a local nebular C iv emitter, which suggests that some of the tension with z > 6 data may be due to existing local samples not yet probing sufficiently high α/Fe abundance ratios. Our results indicate that C iv emission can play a crucial role in the JWST and ELT era by acting as an accessible signpost of very low metallicity (Z/Z$\odot$ < 0.1) massive stars in assembling reionization-era systems.

scholarly journals Extreme conditions in the molecular gas of lensed star-forming galaxies at z ~3

2018 ◽  
Vol 615 ◽  
pp. A142 ◽  
Author(s):  
Paola Andreani ◽  
Edwin Retana-Montenegro ◽  
Zhi-Yu Zhang ◽  
Padelis Papadopoulos ◽  
Chentao Yang ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
High Redshift ◽  
Molecular Gas ◽  
Extreme Conditions ◽  
Atomic Carbon ◽  
Power Sources ◽  
High Redshift Galaxies ◽  
Star Forming ◽  
Nearby Galaxies

Context. Atomic carbon can be an efficient tracer of the molecular gas mass, and when combined to the detection of high-J and low-J CO lines it yields also a sensitive probe of the power sources in the molecular gas of high-redshift galaxies. Aims. The recently installed SEPIA 5 receiver at the focus of the APEX telescope has opened up a new window at frequencies 159–211 GHz allowing the exploration of the atomic carbon in high-z galaxies, at previously inaccessible frequencies from the ground. We have targeted three gravitationally lensed galaxies at redshift of about 3 and conducted a comparative study of the observed high-J CO/CI ratios with well-studied nearby galaxies. Methods. Atomic carbon (CI(2–1)) was detected in one of the three targets and marginally in a second, while in all three targets the J = 7→6 CO line is detected. Results. The CO(7–6)/CI(2–1), CO(7–6)/CO(1–0) line ratios and the CO(7–6)/(far-IR continuum) luminosity ratio are compared to those of nearby objects. A large excitation status in the ISM of these high-z objects is seen, unless differential lensing unevenly boosts the CO line fluxes from the warm and dense gas more than the CO(1–0), CI(2–1), tracing a more widely distributed cold gas phase. We provide estimates of total molecular gas masses derived from the atomic carbon and the carbon monoxide CO(1–0), which within the uncertainties turn out to be equal.

scholarly journals A NEAR-INFRARED EXCESS IN THE CONTINUUM OF HIGH-REDSHIFT GALAXIES: A TRACER OF STAR FORMATION AND CIRCUMSTELLAR DISKS?

2009 ◽  
Vol 706 (2) ◽  
pp. 1020-1035 ◽  
Author(s):  
Erin Mentuch ◽  
Roberto G. Abraham ◽  
Karl Glazebrook ◽  
Patrick J. McCarthy ◽  
Haojing Yan ◽  
...  
Keyword(s):  
Star Formation ◽  
Near Infrared ◽  
High Redshift ◽  
Circumstellar Disks ◽  
Infrared Excess ◽  
High Redshift Galaxies ◽  
The Continuum ◽  
Redshift Galaxies

scholarly journals Local analogs of high-redshift galaxies: Interstellar medium conditions

2016 ◽  
Vol 11 (S321) ◽  
pp. 333-335
Author(s):  
Fuyan Bian ◽  
Lisa J. Kewley ◽  
Michael A. Dopita ◽  
Stephanie Juneau
Keyword(s):  
Interstellar Medium ◽  
Emission Line ◽  
Surface Density ◽  
High Redshift ◽  
Electron Densities ◽  
High Redshift Galaxies ◽  
Diagnostic Diagram ◽  
Nearby Galaxies ◽  
The Difference ◽  
Redshift Galaxies

AbstractLocal analog galaxies play an important role in understanding the properties of high-redshift galaxies. We present a method to select a type of local analog that closely resembles the ionized interstellar medium conditions in high-redshift galaxies. These galaxies are selected based on their locations in the [O III]/Hβ versus [N II]/Hα nebular emission-line diagnostic diagram. The ionization parameters and electron densities in these analogs are comparable to those in z ≃ 2 − 3 galaxies, but higher than those in normal SDSS galaxies by ≃ 0.6 dex and ≃ 0.9 dex, respectively. We find that the high sSFR and SFR surface density can enhance the electron densities and the ionization parameters, but still cannot fully explain the difference in ISM condition between nearby galaxies and the local analogs/high-redshift galaxies.

scholarly journals Extra-Galactic Star Formation Revealed

2004 ◽  
Vol 221 ◽  
pp. 107-117
Author(s):  
Eva Schinnerer
Keyword(s):  
Star Formation ◽  
Early Universe ◽  
High Redshift ◽  
Gas Content ◽  
High Angular Resolution ◽  
Molecular Gas ◽  
Stellar Clusters ◽  
High Redshift Galaxies ◽  
Nearby Galaxies ◽  
Massive Clusters

High angular resolution observations of nearby galaxies in the optical using ground-based and space-based telescopes have not only revealed the presence of young stellar clusters, but also allowed to study their properties in various dynamical environments. These studies have shown that young massive clusters (YMCs) have typical masses of a few 1000 M⊙ and sizes of a few parsec irrespective of their site of formation (such as bulges, spiral arms, starburst rings, or mergers). This points toward a universal formation mechanism for these stellar clusters.Observations of the dust and gas content in high redshift galaxies allows one to study the reservoir for star formation in the early universe. These studies reveal extremely high star formation rates of a few 1000 M⊙ yr−1, while the distribution of the molecular gas still seems to be comparable to what is observed in the local universe. The detection of considerable amounts of molecular gas via its CO lines in the highest redshifted QSOs known today (up to z=6.4) indicates that star formation in the early universe has already produced considerable amounts of metals.

scholarly journals What Can We Learn From Dynamics Of Nearby Galaxies To Study Distant Galaxies?

2006 ◽  
Vol 2 (S235) ◽  
pp. 401-401
Author(s):  
B. Epinat ◽  
P. Amram ◽  
C. Balkowski
Keyword(s):  
High Redshift ◽  
Large Telescope ◽  
Kinematic Parameters ◽  
High Redshift Galaxies ◽  
Distant Galaxies ◽  
Distance Effects ◽  
Nearby Galaxies ◽  
New Instruments ◽  
Larger Sample ◽  
Ongoing Project

This is an ongoing project.During last few years, new instruments like GIRAFFE (Flores, H., Hammer, F., Puech, M., et al., 2006, A&A 455,107) or SINFONI (Förster Schreiber, N.M., Genzel, R., Lehnert, M.D., et al., 2006, ApJ 645,1062) have began investigations on 3D kinematics of high redshift galaxies. This is just the head of the iceberg as Extremely Large Telescope will allow this kind of study on a larger sample. By now, it is important to be able to recover the actual kinematic parameters, and overall to disentangle evolutionnary effects from distance effects.

scholarly journals Quantitative Morphology of High-Redshift Galaxies Using GALEX Ultraviolet Images of Nearby Galaxies

2017 ◽  
Vol 34 (3) ◽  
pp. 183-197
Author(s):  
Bum-Suk Yeom ◽  
Soo-Chang Rey ◽  
Youngkwang Kim ◽  
Youngdae Lee ◽  
Jiwon Chung ◽  
...  
Keyword(s):  
High Redshift ◽  
Quantitative Morphology ◽  
High Redshift Galaxies ◽  
Nearby Galaxies ◽  
Redshift Galaxies

The host galaxies of long gamma-ray bursts through cosmic time

2018 ◽  
Vol 27 (13) ◽  
pp. 1842001 ◽  
Author(s):  
Thomas Krühler
Keyword(s):  
Stellar Population ◽  
Gamma Ray ◽  
High Redshift ◽  
Cosmic Time ◽  
Interstellar Matter ◽  
Host Galaxies ◽  
High Redshift Galaxies ◽  
Star Forming ◽  
Dust Extinction ◽  
High Redshift Universe

As a result of their unprecedented luminosity, long [Formula: see text]-ray bursts (GRBs) and their afterglows pinpoint a population of high-redshift galaxies that is distinct and complementary to galaxies selected by deep sky surveys. In this way, GRBs facilitate a unique view into the high-redshift universe. The bright optical afterglow, for example, serves as a background light for absorption-line spectroscopy, and thus helps us to accurately characterize and understand the cosmochemical evolution of the interstellar matter, the properties of star-forming galaxies through cosmic time or dust extinction at redshifts up to [Formula: see text]. Similarly, detailed studies of the GRB explosion site, and the specific stellar population and galactic environment linked to the GRB, provide important constraints on the physical properties of the GRB progenitor like stellar mass, or on the interplay between metallicity and GRB formation. In this paper, we review recent results in both areas, focusing on novel results from extensive host observations of well-selected GRB samples.

Infrared light curves of dusty & metal-poor AGB stars

2018 ◽  
Vol 14 (S343) ◽  
pp. 406-408
Author(s):  
Steven R. Goldman ◽  
Martha Boyer ◽  
Keyword(s):  
High Redshift ◽  
Light Curves ◽  
Infrared Light ◽  
Agb Stars ◽  
Dust Production ◽  
High Redshift Galaxies ◽  
Evolved Stars ◽  
Nearby Galaxies ◽  
Distance Indicator ◽  
Stellar Masses

AbstractThe effects of metallicity on both the dust production and mass loss of evolved stars have consequences for stellar masses, stellar lifetimes, progenitors of core-collapse SNe, and the origin of dust in the ISM. With the DUST in Nearby Galaxies with Spitzer (DUSTiNGS) survey, we have discovered samples of dusty evolved AGB stars out to the edge of the Local Group with metallicities down to 0.6% solar. This makes them the nearest analogs of AGB stars in high-redshift galaxies. We present new infrared light curves of the dustiest AGB stars in 10 galaxies from the DUSTiNGS survey and show how the infrared Period-Luminosity (PL) relation is affected by dust and metallicity. These results have implications for the efficiency of AGB dust production at high-redshift and for the use of the Mira PL relation as a distance indicator.

scholarly journals Exploring the vertical age structure of the Galactic disc

2015 ◽  
Vol 11 (S319) ◽  
pp. 113-113
Author(s):  
Luca Casagrande
Keyword(s):  
Age Structure ◽  
Milky Way ◽  
High Redshift ◽  
Age Distribution ◽  
Galactic Disc ◽  
High Redshift Galaxies ◽  
Giant Stars ◽  
Stellar Ages ◽  
Red Giant ◽  
Stellar Properties

AbstractWhile in external or high-redshift galaxies we can only measure integrated stellar properties at best, the Milky Way offers us the unique opportunity to study its individual baryonic components, including stars. We use oscillations measured in red giant stars by the Kepler satellite to derive stellar ages and explore the vertical age structure across few kpc of the Milky Way disc. We find that old stars dominate at increasing Galactic heights, whereas closer to the plane a rich zoology of ages exists. The age distribution of stars shows a smooth distribution over the last 10 Gyr, which together with a flat age-metallicity relation is consistent with a quiescent evolution for the Milky Way disc since a redshift of about two.

Sign in / Sign up

Export Citation Format

Share Document