The Stellar Masses and Star Formation Histories of Galaxies atz≈ 6: Constraints fromSpitzerObservations in the Great Observatories Origins Deep Survey

Abstract We develop and implement an inclination-dependent attenuation prescription for spectral energy distribution (SED) fitting and study its impact on derived star formation histories. We apply our prescription within the SED fitting code Lightning to a clean sample of 82, z = 0.21–1.35 disk-dominated galaxies in the Great Observatories Origins Deep Survey North and South fields. To compare our inclination-dependent attenuation prescription with more traditional fitting prescriptions, we also fit the SEDs with the inclination-independent Calzetti et al. (2000) attenuation curve. From this comparison, we find that fits to a subset of 58, z < 0.7 galaxies in our sample, utilizing the Calzetti et al. (2000) prescription, recover similar trends with inclination as the inclination-dependent fits for the far-UV-band attenuation and recent star formation rates. However, we find a difference between prescriptions in the optical attenuation (A V ) that is strongly correlated with inclination (p‐value < 10−11). For more face-on galaxies, with i ≲ 50°, (edge-on, i ≈ 90°), the average derived A V is 0.31 ± 0.11 magnitudes lower (0.56 ± 0.16 magnitudes higher) for the inclination-dependent model compared to traditional methods. Further, the ratio of stellar masses between prescriptions also has a significant (p‐value < 10−2) trend with inclination. For i = 0°–65°, stellar masses are systematically consistent between fits, with log 10 ( M ⋆ inc / M ⋆ Calzetti ) = − 0.05 ± 0.03 dex and scatter of 0.11 dex. However, for i ≈ 80°–90°, the derived stellar masses are lower for the Calzetti et al. (2000) fits by an average factor of 0.17 ± 0.03 dex and scatter of 0.13 dex. Therefore, these results suggest that SED fitting assuming the Calzetti et al. (2000) attenuation law potentially underestimates stellar masses in highly inclined disk-dominated galaxies.

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An older, more quiescent universe from panchromatic SED fitting of the 3D-HST survey

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319009025 ◽

2019 ◽

Vol 15 (S352) ◽

pp. 99-102

Author(s):

Joel Leja ◽

Benjamin D. Johnson ◽

Charlie Conroy ◽

Pieter van Dokkum ◽

Joshua S. Speagle ◽

...

Keyword(s):

Star Formation ◽

Star Formation Rate ◽

Formation Rate ◽

Complex Scaling ◽

Physical Systems ◽

Scaling Relationships ◽

Highly Correlated ◽

Bayesian Inference Framework ◽

Stellar Masses ◽

Star Formation Histories

AbstractGalaxies are complicated physical systems which obey complex scaling relationships; as a result, properties measured from broadband photometry are often highly correlated, degenerate, or both. Therefore, the accuracy of basic properties like stellar masses and star formation rates (SFRs) depend on the accuracy of many second-order galaxy properties, including star formation histories (SFHs), stellar metallicities, dust properties, and many others. Here, we re-assess measurements of galaxy stellar masses and SFRs using a 14-parameter physical model built in the Prospector Bayesian inference framework. We find that galaxies are ∼0.2 dex more massive and have ∼0.2 dex lower star formation rates than classic measurements. These measurements lower the observed cosmic star formation rate density and increase the observed buildup of stellar mass, finally bringing these two metrics into agreement at the factor-of-two level at 0.5 < z < 2.5.

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A redshift-dependent IRX–β dust attenuation relation for TNG50 galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1900 ◽

2020 ◽

Vol 497 (4) ◽

pp. 4773-4794 ◽

Cited By ~ 1

Author(s):

Sebastian Schulz ◽

Gergö Popping ◽

Annalisa Pillepich ◽

Dylan Nelson ◽

Mark Vogelsberger ◽

...

Keyword(s):

Star Formation ◽

Galaxy Formation ◽

Main Sequence ◽

Infrared Excess ◽

Star Forming ◽

Dust Composition ◽

Metal Ratio ◽

Stellar Masses ◽

Dust Attenuation ◽

Star Formation Histories

ABSTRACT We study the relation between the UV slope, β, and the ratio between the infrared- and UV luminosities (IRX) of galaxies from TNG50, the latest installment of the IllustrisTNG galaxy formation simulations. We select 7280 star-forming main-sequence (SFMS) galaxies with stellar mass ≥109 M⊙ at redshifts 0 ≤ z ≤ 4 and perform radiative transfer with skirt to model effects of interstellar medium dust on the emitted stellar light. Assuming a Milky Way dust type and a dust-to-metal ratio of 0.3, we find that TNG50 SFMS galaxies generally agree with observationally derived IRX–β relations at z ≲ 1. However, we find a redshift-dependent systematic offset with respect to empirically derived local relations, with the TNG50 IRX–β relation shifting towards lower β and steepening at higher redshifts. This is partially driven by variations in the dust-uncorrected UV slope of galaxies, due to different star formation histories of galaxies selected at different cosmic epochs; we suggest the remainder of the effect is caused by differences in the effective dust attenuation curves of galaxies as a function of redshift. We find a typical galaxy-to-galaxy variation of 0.3 dex in infrared excess (IRX) at fixed β, correlated with intrinsic galaxy properties: galaxies with higher star formation rates, star formation efficiencies, gas metallicities and stellar masses exhibit larger IRX values. We demonstrate a degeneracy between stellar age, dust geometry, and dust composition: z = 4 galaxies with a Small Magellanic Cloud dust type follow the same IRX–β relation as low-redshift galaxies with MW dust. We provide a redshift-dependent fitting function for the IRX–β relation for MW dust based on our models.

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Spectral synthesis of stellar populations in the 3D era: The CALIFA experience

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314009387 ◽

2014 ◽

Vol 10 (S309) ◽

pp. 93-98

Author(s):

R. Cid Fernandes ◽

E. A. D. Lacerda ◽

R. M. González Delgado ◽

N. Vale Asari ◽

R. García-Benito ◽

...

Keyword(s):

Star Formation ◽

Galaxy Evolution ◽

Spectral Synthesis ◽

Mass Density ◽

Formation Rate ◽

Stellar Populations ◽

Data Cubes ◽

The Mean ◽

Stellar Masses ◽

Star Formation Histories

AbstractMethods to recover the fossil record of galaxy evolution encoded in their optical spectra have been instrumental in processing the avalanche of data from mega-surveys along the last decade, effectively transforming observed spectra onto a long and rich list of physical properties: from stellar masses and mean ages to full star formation histories. This promoted progress in our understanding of galaxies as a whole. Yet, the lack of spatial resolution introduces undesirable aperture effects, and hampers advances on the internal physics of galaxies. This is now changing with 3D surveys. The mapping of stellar populations in data-cubes allows us to figure what comes from where, unscrambling information previously available only in integrated form. This contribution uses our starlight-based analysis of 300 CALIFA galaxies to illustrate the power of spectral synthesis applied to data-cubes. The selected results highlighted here include: (a) The evolution of the mass-metallicity and mass-density-metallicity relations, as traced by the mean stellar metallicity. (b) A comparison of star formation rates obtained from Hα to those derived from full spectral fits. (c) The relation between star formation rate and dust optical depth within galaxies, which turns out to mimic the Schmidt-Kennicutt law. (d) PCA tomography experiments.

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An extension of the MILES library with derived Teff, log g, [Fe/H], and [α/Fe]

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab076 ◽

2021 ◽

Author(s):

A E García Pérez ◽

P Sánchez-Blázquez ◽

A Vazdekis ◽

C Allende Prieto ◽

A de C Milone ◽

...

Keyword(s):

Star Formation ◽

Parameter Space ◽

Important Ingredient ◽

Chemical Abundances ◽

Reliable Determination ◽

Stellar Masses ◽

Star Formation Histories ◽

Good Coverage ◽

Data Reductions

Abstract Extragalactic astronomy and stellar astrophysics are intrinsically related. In fact, the determination of important galaxy properties such as stellar masses, star formation histories or chemical abundances relies on the ability to model their stellar populations. One important ingredient of these models are stellar libraries. Empirical libraries must have a good coverage of Teff, [Z/H], and surface gravity, and have these parameters reliably determined. MILES is one of the most widely used empirical libraries. Here we present an extension of this library with 205 new stars especially selected to cover important regions of the parameter space, including metal poor stars down to [Fe/H] ∼ −1.0. We describe the observations and data reductions as well as a new determination of the stellar parameters, including [α/Fe] ratio. The new MILES library contains 1070 stars with homogeneous and reliable determination of [Fe/H], Teff, log g and [α/Fe] ratio.

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Outflows in low-mass galaxies at z >1

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316011686 ◽

2016 ◽

Vol 11 (S321) ◽

pp. 339-341

Author(s):

Michael V. Maseda ◽

Keyword(s):

Star Formation ◽

High Redshift ◽

Theoretical Models ◽

Potential Wells ◽

Low Mass ◽

Hydrodynamical Simulations ◽

Gas Accretion ◽

Stellar Masses ◽

Star Formation Histories ◽

Cold Gas

AbstractStar formation histories of local dwarf galaxies, derived through resolved stellar populations, appear complex and varied. The general picture derived from hydrodynamical simulations is one of cold gas accretion and bursty star formation, followed by feedback from supernovae and winds that heat and eject the central gas reservoirs. This ejection halts star formation until the material cools and re-accretes, resulting in an episodic SFH, particularly at stellar masses below ~ 109 M⊙. Such feedback has often been cited as the driving force behind the observed slowly-rising rotation curves in local dwarfs, due to an under-density of dark matter compared to theoretical models, which is one of the primary challenges to LCDM cosmology. However, these events have not yet been directly observed at high-redshift. Recently, using HST imaging and grism spectroscopy, we have uncovered an abundant population of low-mass galaxies (M* < 109 M⊙) at z = 1 - 2 that are undergoing strong bursts of star formation, in agreement with the theoretical predictions. These Extreme Emission Line Galaxies, with high specific SFRs and shallow gravitational potential wells, are ideal places to test the theoretical prediction of strong feedback-driven outflows. Here we use deep MUSE spectroscopy to search these galaxies for signatures of outflowing material, namely kinematic offsets between absorption lines (in the restframe optical and UV), which trace cool gas, and the nebular emission lines, which define the systemic redshift of the galaxy. Although the EELGs are intrinsically very faint, stacked spectra reveal blueshifted velocity centroids for Fe II absorption, which is indicative of outflowing cold gas. This represents the first constraint on outflows in M* < 109 M⊙ galaxies at z = 1 - 2. These outflows should regulate the star formation histories of low-mass galaxies at early cosmic times and thus play a crucial role in galaxy growth and evolution.

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Rejuvenated galaxies with very old bulges at the origin of the bending of the main sequence and of the ‘green valley’

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2130 ◽

2019 ◽

Vol 489 (1) ◽

pp. 1265-1290 ◽

Cited By ~ 8

Author(s):

Chiara Mancini ◽

Emanuele Daddi ◽

Stéphanie Juneau ◽

Alvio Renzini ◽

Giulia Rodighiero ◽

...

Keyword(s):

Star Formation ◽

Main Sequence ◽

Formation Rate ◽

Very Old ◽

Massive Galaxies ◽

Star Forming ◽

Late Event ◽

Age Of The Universe ◽

Stellar Masses ◽

Star Formation Histories

ABSTRACT We investigate the nature of star-forming galaxies with reduced specific star formation rate (sSFR) and high stellar masses, those ‘green valley’ objects that seemingly cause a reported bending, or flattening, of the star-forming main sequence. The fact that such objects host large bulges recently led some to suggest that the internal formation of bulges was a late event that induced the sSFRs of massive galaxies to drop in a slow downfall, and thus the main sequence to bend. We have studied in detail a sample of 10 galaxies at 0.45 < z < 1 with secure SFR from Herschel, deep Keck optical spectroscopy, and HST imaging from CANDELS allowing us to perform multiwavelength bulge to disc decomposition, and to derive star formation histories for the separated bulge and disc components. We find that the bulges hosted in these systems below main sequence are virtually all maximally old, with ages approaching the age of the Universe at the time of observation, while discs are young (〈 T50〉 ∼ 1.5 Gyr). We conclude that, at least based on our sample, the bending of the main sequence is, for a major part, due to rejuvenation, and we disfavour mechanisms that postulate the internal formation of bulges at late times. The very old stellar ages of our bulges suggest a number density of early-type galaxies at z = 1–3 higher than actually observed. If confirmed, this might represent one of the first direct validations of hierarchical assembly of bulges at high redshifts.

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An ALMA survey of the S2CLS UDS field: optically invisible submillimetre galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab283 ◽

2021 ◽

Vol 502 (3) ◽

pp. 3426-3435

Author(s):

Ian Smail ◽

U Dudzevičiūtė ◽

S M Stach ◽

O Almaini ◽

J E Birkin ◽

...

Keyword(s):

Star Formation ◽

Surface Density ◽

Near Infrared ◽

Infrared Imaging ◽

High Redshift ◽

Formation Rate ◽

High Attenuation ◽

Deep Survey ◽

Stellar Masses ◽

Dust Attenuation

ABSTRACT We analyse a robust sample of 30 near-infrared-faint (KAB > 25.3, 5σ) submillimetre galaxies (SMGs) selected from a 0.96 deg2 field to investigate their properties and the cause of their faintness in optical/near-infrared wavebands. Our analysis exploits precise identifications based on Atacama Large Millimeter Array (ALMA) 870-μm continuum imaging, combined with very deep near-infrared imaging from the UKIDSS Ultra Deep Survey. We estimate that SMGs with KAB > 25.3 mag represent 15 ± 2 per cent of the total population brighter than S870 = 3.6 mJy, with a potential surface density of ∼450 deg−2 above S870 ≥ 1 mJy. As such, they pose a source of contamination in surveys for both high-redshift ‘quiescent’ galaxies and very high redshift Lyman-break galaxies. We show that these K-faint SMGs represent the tail of the broader submillimetre population, with comparable dust and stellar masses to KAB ≤ 25.3 mag SMGs, but lying at significantly higher redshifts (z = 3.44 ± 0.06 versus z = 2.36 ± 0.11) and having higher dust attenuation (AV = 5.2 ± 0.3 versus AV = 2.9 ± 0.1). We investigate the origin of the strong dust attenuation and find indications that these K-faint galaxies have smaller dust continuum sizes than the KAB ≤ 25.3 mag galaxies, as measured by ALMA, which suggests their high attenuation is related to their compact sizes. We identify a correlation of dust attenuation with star formation rate surface density (ΣSFR), with the K-faint SMGs representing the higher ΣSFR and highest AV galaxies. The concentrated, intense star formation activity in these systems is likely to be associated with the formation of spheroids in compact galaxies at high redshifts, but as a result of their high obscuration these galaxies are completely missed in ultraviolet, optical, and even near-infrared surveys.

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Massive and Evolved Galaxies at z ≥ 5

Proceedings of the International Astronomical Union ◽

10.1017/s1743921306010192 ◽

2006 ◽

Vol 2 (S235) ◽

pp. 368-372 ◽

Cited By ~ 1

Author(s):

T. Wiklind ◽

B. Mobasher ◽

M. Dickinson ◽

H. Ferguson ◽

M. Giavalisco ◽

...

Keyword(s):

Star Formation ◽

Stellar Population ◽

Formation Rate ◽

Broad Band ◽

Photometric Redshifts ◽

Color Selection ◽

Final Sample ◽

Star Formation Activity ◽

Deep Survey ◽

Stellar Masses

AbstractWe search for massive and evolved galaxies at z ≥ 5 in the Great Observatories Origins Deep Survey (GOODS) southern field. Combining HST ACS, VLT ISAAC and Spitzer IRAC broad–band photometric data, we develop a color selection technique to identify candidates for being evolved galaxies at high redshifts. The color selection is primarily based on locating the Balmer–break using the K- and 3.6 μm bands. Stellar population synthesis models are fitted to the SEDs of these galaxies to identify the final sample. We find 11 candidates with photometric redshifts in the range 4.9 < z < 5.6, dominated by an old stellar population, with ages 0.2-1.0 Gyr, and stellar masses in the range (0.7 − 5) × 1011 M⊙. Most of the candidates have modest amounts of internal dust extinction. The majority of the stars in these galaxies were formed at z>9 and the current star formation activity is a few percent of the inferred initial star formation rate.

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ALMA twenty-six arcmin2 survey of GOODS-S at one millimeter (ASAGAO): Millimeter properties of stellar mass selected galaxies

Publications of the Astronomical Society of Japan ◽

10.1093/pasj/psaa057 ◽

2020 ◽

Vol 72 (4) ◽

Author(s):

Yuki Yamaguchi ◽

Kotaro Kohno ◽

Bunyo Hatsukade ◽

Tao Wang ◽

Yuki Yoshimura ◽

...

Keyword(s):

Star Formation ◽

Galaxy Evolution ◽

Star Formation Rate ◽

Signal To Noise Ratio ◽

Formation Rate ◽

Stellar Mass ◽

Star Forming ◽

Deep Survey ◽

Stellar Masses ◽

Relationship Of

Abstract We make use of the ALMA twenty-Six Arcmin2 survey of GOODS-S At One-millimeter (ASAGAO), deep 1.2 mm continuum observations of a 26-arcmin2 region in the Great Observatories Origins Deep Survey-South (GOODS-S) obtained with Atacama Large Millimeter/sub-millimeter Array (ALMA), to probe dust-enshrouded star formation in K-band selected (i.e., stellar mass selected) galaxies, which are drawn from the FourStar Galaxy Evolution Survey (ZFOURGE) catalog. Based on the ASAGAO combined map, which was created by combining ASAGAO and ALMA archival data in the GOODS-South field, we find that 24 ZFOURGE sources have 1.2 mm counterparts with a signal-to-noise ratio >4.5 (1σ ≃ 30–70 μJy beam−1 at 1.2 mm). Their median redshift is estimated to be $z$median = 2.38 ± 0.14. They generally follow the tight relationship of the stellar mass versus star formation rate (i.e., the main sequence of star-forming galaxies). ALMA-detected ZFOURGE sources exhibit systematically larger infrared (IR) excess (IRX ≡ LIR/LUV) compared to ZFOURGE galaxies without ALMA detections even though they have similar redshifts, stellar masses, and star formation rates. This implies the consensus stellar-mass versus IRX relation, which is known to be tight among rest-frame-ultraviolet-selected galaxies, cannot fully predict the ALMA detectability of stellar-mass-selected galaxies. We find that ALMA-detected ZFOURGE sources are the main contributors to the cosmic IR star formation rate density at $z$ = 2–3.

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