Star Formation Rates Of Galaxies Research Articles

Spatially Resolved Comparison of SFRs from UV and Hα in GASP Gas-stripped Galaxies

Star formation rates (SFRs) in galaxies offer a view of various physical processes across them, and are measured using various tracers, such as Hα and ultraviolet (UV). Different physical mechanisms can affect Hα and UV emission, resulting in a discrepancy in the corresponding SFR estimates (ΔSFR). We investigate the effects of ram pressure on the SFR measurements and ΔSFR across five galaxies from the GASP survey caught in the late stages of gas stripping due to ram pressure. We probe spatially resolved ΔSFR at pixel scales of 0.5 kpc, and compare disks to tails and regions dominated by the dense gas to diffuse ionized gas (DIG) regions. The regions dominated by dense gas show similar SFR values for UV and Hα tracers, while the regions dominated by the DIG show up to 0.5 dex higher SFR(UV). There is a large galaxy-by-galaxy variation in ΔSFR, with no difference between the disks and the tails. We discuss the potential causes of variations in ΔSFR between the dense gas and DIG areas. We conclude that the dominant cause of discrepancy are recent variations in star formation histories, where star formation recently dropped in the DIG-dominated regions leading to changes in ΔSFR. The areal coverage of the tracers shows areas with Hα and no UV emission; these areas have LINER-like emission (excess in [O i λ6300]/Hα line ratio), indicating that they are ionized by processes other than star formation.

SAGAbg. II. The Low-mass Star-forming Sequence Evolves Significantly between 0.05 < z < 0.21

The redshift-dependent relation between galaxy stellar mass and star formation rate (SFR), known as the star-forming sequence (SFS), is a key observational yardstick for galaxy assembly. We use the SAGAbg-A sample of background galaxies from the Satellites Around Galactic Analogs (SAGA) Survey to model the low-redshift evolution of the low-mass SFS. The sample is comprised of 23,258 galaxies with Hα-based SFRs spanning 6<log10(M⋆/[M⊙])<10 and z < 0.21 (t < 2.5 Gyr). Although it is common to bin or stack galaxies at z ≲ 0.2 for galaxy population studies, the difference in lookback time between z = 0 and z = 0.21 is comparable to the time between z = 1 and z = 2. We develop a model to account for both the physical evolution of low-mass SFS and the selection function of the SAGA Survey, allowing us to disentangle redshift evolution from redshift-dependent selection effects across the SAGAbg-A redshift range. Our findings indicate significant evolution in the SFS over the last ∼2.5 Gyr, with a rising normalization: 〈SFR(M⋆=108.5M⊙)〉(z)=1.24−0.23+0.25z−1.47−0.03+0.03 . We also identify the redshift limit at which a static SFS is ruled out at the 95% confidence level, which is z = 0.05 based on the precision of the SAGAbg-A sample. Comparison with cosmological hydrodynamic simulations reveals that some contemporary simulations underpredict the recent evolution of the low-mass SFS. This demonstrates that the recent evolution of the low-mass SFS can provide new constraints on the assembly of the low-mass Universe and highlights the need for improved models in this regime.

The SAGA Survey. V. Modeling Satellite Systems around Milky Way–Mass Galaxies with Updated UniverseMachine

Abstract Environment plays a critical role in shaping the assembly of low-mass galaxies. Here, we use the UniverseMachine (UM) galaxy–halo connection framework and Data Release 3 of the Satellites Around Galactic Analogs (SAGA) Survey to place dwarf galaxy star formation and quenching into a cosmological context. UM is a data-driven forward model that flexibly parameterizes galaxy star formation rates (SFRs) using only halo mass and assembly history. We add a new quenching model to UM, tailored for galaxies with m ⋆ ≲ 109 M ⊙, and constrain the model down to m ⋆ ≳ 107 M ⊙ using new SAGA observations of 101 satellite systems around Milky Way (MW)–mass hosts and a sample of isolated field galaxies in a similar mass range from the Sloan Digital Sky Survey. The new best-fit model, “UM-SAGA,” reproduces the satellite stellar mass functions, average SFRs, and quenched fractions in SAGA satellites while keeping isolated dwarfs mostly star-forming. The enhanced quenching in satellites relative to isolated field galaxies leads the model to maximally rely on halo assembly to explain the observed environmental quenching. Extrapolating the model down to m ⋆ ∼ 106.5 M ⊙ yields a quenched fraction of ≳30% for isolated field galaxies and ≳80% for satellites of MW-mass hosts at this stellar mass. Spectroscopic surveys can soon test this specific prediction to reveal the relative importance of internal feedback, cessation of mass and gas accretion, satellite-specific gas processes, and reionization for the evolution of faint low-mass galaxies.

Physical properties of extreme emission-line galaxies at z ∼ 4–9 from the JWST CEERS survey

Context. Extreme emission line galaxies (EELGs) are typically characterized by high equivalent widths (EWs) which are driven by elevated specific star formation rates (sSFRs) in low-mass galaxies with subsolar metallicities and little dust. Such extreme systems are exceedingly rare in the local universe, but the number density of EELGs increases with increasing redshift. Such starburst galaxies are currently strongly presumed to be the main drivers of hydrogen reionization over 5.5 &lt; z &lt; 15, which serves to motivate many of the searches for high-z EELGs. Aims. We aim to characterize the physical properties of a sample of ∼730 EELGs at 4 ≲ z &lt; 9 photometrically selected from the CEERS survey using JWST/NIRCam. We validate our method and demonstrate the main physical properties of a subset of EELGs using NIRSpec spectra. Methods. We create synthetic NIRCam observations of EELGs using empirical templates based on ∼2000 local metal-poor starbursts to select EELGs based on color-color criteria. We study their properties based on SED fitting and flux excess from emission lines in the photometric filters. Results. Our sample of EELGs has a mean stellar mass of 107.84 M⊙ with high sSFRs from SED fitting with a mean value of 10−7.03 yr−1. We consider a delayed-τ model for the star formation history and find our sample of EELGs are young with a mean value of the time after the onset of star formation of 45 Myr. We find that they have similar line ratios to local metal-poor starburst galaxies with high log([OIII]/Hβ) ≳ 0.4−1 which indicates that star formation may be the dominant source of ionization in these galaxies. Based on the photometric fluxes and morphologies, we find an increase of EW([OIII]+Hβ) with sSFR and ΣSFR, and a decrease with age and stellar mass. The sample of EELGs can reach ΣSFR &gt; 10 M⊙ yr−1 kpc−2 which indicate they are strong candidates of LyC leakers. Another indirect indicator is the high values of O32 &gt; 5 that can be reached for some galaxies in the sample. This indicates that they may have the conditions to facilitate the escape of ionizing photons.

Merging galaxies in isolated environments

Context. It is now well known that certain massive galaxies undergo enormous enhancements in their star formation rate (SFR) when they undergo major mergers. These enhancements can be as high as 100 times the SFR of unperturbed galaxies of the same stellar mass. Previous works have found that the size of this boost in star formation (SF) is related to the morphology of and the proximity to the companion. The same trend has also been observed for the fraction of active galactic nuclei (AGN), where galaxies that are closer together tend to have higher AGN fractions. Aims. We aim to analyse the SF enhancement and AGN fraction evolution during the merger process by using a more timeline-like merger sequence. Additionally, we aim to determine the relation between the SF enhancement in mergers and the morphology of the galaxies involved. Methods. Taking advantage of the stellar masses (M*) and SFRs of the ∼600 nearby isolated mergers obtained in our previous study, we calculated the distance of each of our galaxies from the star-forming main sequence (MS; specific SFR (sSFR)/sSFRMS), which werefer to as the SF mode. We then analysed how the SF mode varies during the merger process as a function of morphology and M*. Additionally, we analysed the AGN content of our mergers, using multiple diagnostics based on emission line ratios and WISE colours. Results. We observed that, overall, merging galaxies show an SF mode that is governed by their morphology. Spirals typically show high SF mode values, while highly disturbed (HD) galaxies are generally even more enhanced (median values of +0.8 dex and +1.08 dex above the MS, respectively). In contrast, elliptical and lenticular galaxies show the lowest SF modes, as expected. However, even they show SF enhancement compared to their unperturbed counterparts. For example, their median SF mode is just within the 1-sigma scatter of the MS, and this can occur even before the galaxies have coalesced. We observed a trend for the SF mode to gradually increase with increasing merger stage. We did not find a clear dependency of the observed AGN fraction on the merger stage for the majority of our classification methods. Conclusions. We find mergers can significantly enhance SF in galaxies of all morphologies. For early-type galaxies, this could suggest that some gas was present prior to the merger, which may be triggered to form stars by the tidal interaction. As the SF enhancement continues throughout the merger process, this suggests that the enhancement may be a long-lived event, contrary to the short starbursts seen in some models.

The role of stellar mass in the cosmic history of star formation as seen by Herschel and ALMA

Aims . We explore the contribution of galaxies, as a function of their stellar mass, to the cosmic star formation history (CSFH). In order to avoid uncertain extrapolations of the infrared luminosity function, which is often polluted by the contribution of starbursts, we base our analysis on stellar mass. Attenuation by dust is accounted for thanks to the combination of deep surveys by Herschel and the Atacama Large Millimeter/submillimeter array (ALMA). Methods. We combined for the first time the deepest Herschel (GOODS-South, GOODS-North, COSMOS and UDS) and ALMA (GOODS-South) surveys. We constrained the star formation rate (SFR), dust mass ($M_ dust $), dust temperature ($T_ dust $) and gas mass ($M_ gas $) of galaxies as a function of their stellar mass ($M_ star $) from $z to $z by performing a stacking analysis of over 128,000 Hubble Space Telescope (HST) H -band selected galaxies. We studied the evolution of the star formation efficiency of galaxies as a function of redshift and $M_ star Results . We show that the addition of ALMA to Herschel allows us to reach lower $M_ star $ and higher redshifts. We confirm that the SFR-$M_ star $ star formation main sequence (MS) follows a linear evolution with a slope close to unity with a bending at the high-mass end at $z&lt;2$. The mean $T_ dust $ of MS galaxies evolves linearly with redshift, with no apparent correlation with $M_ star $. We show that, up to $z massive galaxies (i.e. star M_ odot $) account for most of the total SFR density ($ SFR $), while the contribution of lower-mass galaxies (i.e. $M_ star M_ odot $) is rather constant. We compare the evolution of star-forming galaxy (SFGs) to the cosmological simulation TNG100. We find that TNG100 exhibits a noticeable difference in the evolution of the CSFH, that is, the marked evolution of massive galaxies found in the observations appears to be smoothed in the simulation, possibly due to feedback that is too efficient. In this mass complete analysis, $H$-dropout (also called HST-dark) galaxies account for $ 23&lt;!PCT!&gt;$ of the CSFH in massive galaxies at $z$$&gt;$3. Finally, we find hints that the star formation efficiency of distant galaxies ($z$=3--5) is stronger (shorter depletion time) as compared to low-redshift galaxies.

Measuring 60 pc-scale Star Formation Rate of the Nearby Seyfert Galaxy NGC 1068 with ALMA, HST, VLT/MUSE, and VLA

The star formation rate (SFR) is a fundamental parameter for describing galaxies and inferring their evolutionary course. H ii regions yield the best measure of instantaneous SFR in galaxies, although the derived SFR can have large uncertainties depending on tracers and assumptions. We present an SFR calibration for the entire molecular gas disk of the nearby Seyfert galaxy NGC 1068, based on our new high-sensitivity Atacama Large Millimeter/submillimeter Array 100 GHz continuum data at 55 pc (= 0.″8) resolution in combination with the Hubble Space Telescope Paα line data. In this calibration, we account for the spatial variations of dust extinction, electron temperature of H ii regions, AGN contamination, and diffuse ionized gas (DIG) based on publicly available multiwavelength data. Especially, given the extended nature and the possible nonnegligible contribution to the total SFR, a careful consideration of DIG is essential. With a cross-calibration between two corrected ionized gas tracers (free–free continuum and Paα), the total SFR of the NGC 1068 disk is estimated to be 3.2 ± 0.5 M ⊙ yr−1, one-third of the SFR without accounting for DIG (9.1 ± 1.4 M ⊙ yr−1). We confirmed a high SFR around the southern bar end and the corotation radius, which is consistent with the previous SFR measurements. In addition, our total SFR exceeds the total SFR based on 8 μm dust emission by a factor of 1.5. We attribute this discrepancy to the differences in the young stars at different stages of evolution traced by each tracer and their respective timescales. This study provides an example to address the various uncertainties in conventional SFR measurements and their potential to lead to significant SFR miscalculations.

Exploring Filament Galaxies Using AstroSat/UVIT

Abstract We present results from our deep far-ultraviolet (FUV) survey using AstroSat/UVIT of a filamentary structure at z ∼0.072. A total of four filaments comprising 58 galaxies were probed in our study. We detect 18 filament galaxies in our FUV observation. All filament galaxies are further classified based on their photometric color, nuclear activity, and morphology. The filaments contain galaxies with mixed stellar population types and structures. We do not detect galaxies in our UVIT survey up to a distance of 0.4 Mpc h −1 from the filament axis, implying a lack of recent star formation in the inner region of filaments. The FUV star formation rate (SFR) for star-forming galaxies agrees well with the SFR144MHz calculated using Low-Frequency Array radio-continuum observations. We witness an increase in the FUV specific-SFR (sSFR) of filament galaxies with increasing distance from the filament spine (D fil). The intermediate-to-high stellar mass filament galaxies were more star-forming than cluster galaxies in a fixed stellar mass bin. The FUV morphology of some filament galaxies detected in the filament outskirts (D fil ≳ 0.7 Mpc h −1) is comparable to or slightly extended than their optical counterpart. The mass assembly of galaxies examined by estimating (FUV − r) color gradients shows that more “red-cored’ galaxies reside in the outer region of the filaments. Our results prove that the likelihood of merger interaction and gas starvation increases when approaching the filament spine. We report a definitive and inhomogeneous impact of filaments on the galaxies residing inside them.

The effects of stellar and AGN feedback on the cosmic star formation history in the simba simulations

ABSTRACT Using several variants of the cosmological simba simulations, we investigate the impact of different feedback prescriptions on the cosmic star formation history. Adopting a global-to-local approach, we link signatures seen in global observables, such as the star formation rate density (SFRD) and the galaxy stellar mass function (GSMF), to feedback effects in individual galaxies. We find a consistent picture: stellar feedback mainly suppresses star formation below halo masses of $M_{\rm H} = 10^{12} \rm \, {\rm M}_{\odot }$ and before $z = 2$, whereas AGN feedback quenches the more massive systems after $z = 2$. Among simba’s AGN feedback modes, AGN jets are the dominant quenching mechanism and set the shape of the SFRD and the GSMF at late times. AGN-powered winds only suppress the star formation rate in intermediate-mass galaxies ($M_{\rm \star } = 10^{9.5 - 10} \rm \, {\rm M}_{\odot }$), without affecting the overall stellar mass-assembly significantly. At late times, the AGN X-ray feedback mode mainly quenches residual star formation in massive galaxies. Our analysis reveals that this mode is also necessary to produce the first fully quenched galaxies before $z=2$, where the jets alone are inefficient. These initially highly star-forming galaxies contain relatively large black holes, likely strengthening the X-ray-powered heating and ejection of gas from the dense, central region of galaxies. Such extra heating source quenches the local star formation and produces a more variable accretion rate. More generally, this effect also causes the break down of correlations between the specific star formation rate, the accretion rate and the black hole mass.

CHANG-ES. XXXII. Spatially Resolved Thermal–Nonthermal Separation from Radio Data Alone—New Probes into NGC 3044 and NGC 5775

We have carried out spatially resolved thermal–nonthermal separation on two edge-on galaxies, NGC 3044 and NGC 5775, using only radio data. Narrowband imaging within a frequency band that is almost contiguous from 1.25 to 7.02 GHz (L band, S band, and C band) has allowed us to fit spectra and construct thermal, nonthermal, and nonthermal spectral index maps. This method does not require any ancillary Hα and IR data or rely on dust corrections that are challenging in edge-on galaxies. For NGC 3044, at 15″ resolution, we find a median thermal fraction of ∼13% with an estimated uncertainty in this fraction of ∼50% at 4.13 GHz. This compares well with the Hα mixture method results. We uncovered evidence for a vertical outflow feature reaching at least z ∼ 3.5 kpc in projection above the plane, reminiscent of M82's starburst wind. For the higher star formation rate galaxy, NGC 5775, at 12″ resolution, we find a median thermal fraction of 44% at 4.13 GHz with an estimated error on this fraction of 17%. Both galaxies show a change of slope (flattening) in L band. These results suggest that a radio-only method for separating thermal from nonthermal emission is not only feasible, but able to reveal new features that might otherwise be obscured in edge-on disks.

The cosmic rate of pair-instability supernovae

Abstract Pair-instability supernovae (PISNe) have crucial implications for many astrophysical topics, including the search for very massive stars, the black hole mass spectrum, and galaxy chemical enrichment. To this end, we need to understand where PISNe are across cosmic time, and what are their favourable galactic environments. We present a new determination of the PISN rate as a function of redshift, obtained by combining up-to-date stellar evolution tracks from the PARSEC and FRANEC codes, with an up-to-date semi-empirical determination of the star formation rate and metallicity evolution of star-forming galaxies throughout cosmic history. We find the PISN rate to exhibit a huge dependence on the model assumptions, including the criterion to identify stars unstable to pair production, and the upper limit of the stellar initial mass function. Remarkably, the interplay between the maximum metallicity at which stars explode as PISNe, and the dispersion of the galaxy metallicity distribution, dominates the uncertainties, causing a ∼ seven-orders-of-magnitude PISN rate range. Furthermore, we show a comparison with the core-collapse supernova rate, and study the properties of the favourable PISN host galaxies. According to our results, the main contribution to the PISN rate comes from metallicities between ∼10−3 and 10−2, against the common assumption that views very-low-metallicity, Population III stars as exclusive or dominant PISN progenitors. The strong dependencies we find offer the opportunity to constrain stellar and galaxy evolution models based on possible future (or the lack of) PISN observations.

Low-redshift Lyman Continuum Survey (LzLCS)

Context. Sources that leak Lyman continuum (LyC) photons and lead to the reionisation of the universe are an object of intense study using multiple observing facilities. Recently, the Low-redshift LyC Survey (LzLCS) has presented the first large sample of LyC emitting galaxies at low redshift (z ∼ 0.3) with the Hubble Space Telescope Cosmic Origins Spectrograph. The LzLCS sample contains a robust estimate of the LyC escape fraction (fescLyC) for 66 galaxies, spanning a wide range of fescLyC values. Aims. Here, we aim to study the dependence of fescLyC on the radio continuum (RC) properties of LzLCS sources. Overall, RC emission can provide unique insights into the role of supernova feedback, cosmic rays (CRs), and magnetic fields from its non-thermal emission component. RC emission is also a dust-free tracer of the star formation rate (SFR) in galaxies. Methods. In this study, we present Karl G. Jansky Very Large Array (VLA) RC observations of the LzLCS sources at gigahertz (GHz) frequencies. We performed VLA C (4−8 GHz) and S (2−4 GHz) band observations for a sample of 53 LzLCS sources. We also observed a sub-sample of 17 LzLCS sources in the L (1−2 GHz) band. We detected RC from both C- and S-bands in 24 sources for which we are able to estimate their radio spectral index across 3−6 GHz, denoted as α6 GHz3 GHz. We also used the RC luminosity to estimate their SFRs. Results. The radio spectral index of LzLCS sources spans a wide range, from flat (≥ − 0.1) to very steep (≤ − 1.0). They have a steeper mean α6 GHz3 GHz (≈ − 0.92) compared to that expected for normal star-forming galaxies (α6 GHz3 GHz ≈ −0.64). They also show a larger scatter in α6 GHz3 GHz (∼0.71) compared to that of normal star-forming galaxies (∼0.15). The strongest leakers in our sample show flat α6 GHz3 GHz, weak leakers have α6 GHz3 GHz close to normal star-forming galaxies and non-leakers are characterized by steep α6 GHz3 GHz. We argue that a combination of young ages, free-free absorption, and a flat cosmic-ray energy spectrum can altogether lead to a flat α6 GHz3 GHz for strong leakers. Non-leakers are characterized by steep spectra which can arise due to break or cutoff at high frequencies. Such a cutoff in the spectrum can arise in a single injection model of CRs characteristic of galaxies which have recently stopped star-formation. The dependence of fescLyC on α6 GHz3 GHz (which is orientation-independent) suggests that the escape of LyC photons is not highly direction-dependent at least to the first order. The radio-based SFRs (SFRRC) of LzLCS sources show a large offset (∼0.59 dex) from the standard SFRRC calibration. We find that adding α6 GHz3 GHz as a second parameter helps us to calibrate the SFRRC with SFRUV and SFRHβ within a scatter of ∼0.21 dex. Conclusions. For the first time, we have found a relation between α6 GHz3 GHz and fescLyC. This hints at the interesting role of supernovae feedback, CRs, and magnetic fields in facilitating the escape (alternatively, and/or the lack) of LyC photons.

A Survey of Galaxy Pairs in the SDSS Photometric Images based on Faster-RCNN

Galaxy pairs hold significant importance in understanding the evolution of galaxies, and the extensive search for a large sample of galaxy pairs is meaningful. In this article, we develop a deep learning-based approach for the search of galaxy pairs and conduct a comprehensive search on Sloan Digital Sky Survey (SDSS) images. In nine million photometric images, 17,965 physical galaxy pairs with spectral or photometric redshifts are detected. Four sets of results are provided, including physical pairs determined by two spectral redshifts, two photometric redshifts, one spectral redshift, and one photometric redshift, and visual irregular pairs that have no precise redshift information but can be inferred as physical galaxy pairs based on the morphological changes. Then their morphological and physical characteristics are explored, the redshifts of most targets are around 0.1, and as the redshift difference between two galaxies increases, the number of galaxy pairs gradually reduces. The distributions of star formation rate (SFR) are not the same for different morphologies of galaxy pairs, irregular pairs have higher SFR than the other three types, and statistics indicate that the SFR of galaxies depends on both nearby galaxies and internal properties. Color and stellar mass are also key properties of galaxies which can reflect the status of galaxy pairs. Compared to other surveys, a greater number of galaxy pair targets are detected, and this is also the first extensive detection of galaxy pairs in SDSS images using photometric redshifts. These galaxy pair samples can greatly aid in the study of galaxy evolution.

Evolution of the star formation rate and Sigma_SFR of galaxies at cosmic morning (4&lt;z&lt;10)

The galaxy-integrated star formation rate (SFR) surface density measurement ($ SFR $) has been proposed as a valuable diagnostic of the mass accumulation in galaxies given it is more tightly related to the physics of star formation and stellar feedback than other indicators. In this work, we assembled a statistical sample of $230$ galaxies observed with JWST in the GLASS and CEERS spectroscopic surveys to estimate Balmer line-based dust attenuations and SFRs (i.e., from Halpha , Hbeta , and Hgamma ), along with the UV rest-frame effective radii. We studied the evolution of galaxy SFR and $ SFR $ in the first $1.5$ billion years of our Universe, from a redshift of $z to $z We found that $ SFR $ is mildly increasing with redshift with a linear slope of $0.16 0.06$. We explored the dependence of SFR and $ SFR $ on stellar mass, showing that a star-forming main sequence and a $ SFR $ main sequence are present out to $z=10$. This dependence exhibits a similar slope compared to the same relations at lower redshifts, but with a higher normalization. We find that the specific SFR (sSFR) and $ SFR $ are correlated with the ratio and with indirect estimates of the escape fraction of Lyman continuum photons; hence, they are likely to play an important role in the evolution of ionization conditions at higher redshifts and in the escape of ionizing radiation. We also searched for spectral outflow signatures in the Halpha and emission lines in a subset of galaxies observed at high resolution (R$=2700$) by the GLASS survey, finding an outflow incidence of $2/11$ 32&lt;!PCT!&gt; 9&lt;!PCT!&gt; $) at $z&lt;6$, but no evidence at $z&gt;6$ ($0/6$, $&lt;26&lt;!PCT!&gt;$). Finally, we find a positive correlation between A$_V$ and $ SFR $, and a flat trend as a function of sSFR, indicating that there is no evidence of a drop in A$_V$ in extremely star-forming galaxies between $z 4$ and $ 10$. This result might be at odds with a dust-clearing outflow scenario, which may instead take place at redshifts of $z 10$, as suggested by some theoretical models.

Non-monotonic relations of galaxy star formation, radius, and structure at fixed stellar mass

ABSTRACT We investigate the relation between galaxy structure and star formation rate (SFR) in a sample of $\sim 2.9\times 10^{4}$ central galaxies with $z\lt 0.0674$ and axial ratios $b/a\gt 0.5$. The star-forming main sequence (SFMS) shows a bend around the stellar mass of $M_\ast \le {}M_c=2\times 10^{10}{}{\rm M}_{\odot }$. At $M_\ast \le {}M_c$, the SFMS follows a power-law $\text{SFR}\propto {}M_\ast ^{0.85}$, while at higher masses it flattens. $M_c$ corresponds to a dark matter halo mass of $M_\text{vir}\sim {}10^{11.8}{\rm M}_{\odot }$ where virial shocks occurs. Some galaxy structure (e.g. half-light radius, $R_e$) exhibits a non-monotonic dependence across the SFMS at a fixed $M_\ast$. We find $\text{SFR}\propto {R_e^{-0.28}}$ at fixed $M_\ast$, consistent with the global Kennicutt–Schmidt (KS) law. This finding suggests that galaxy sizes contribute to the scatter of the SFMS. However, at $M_\ast \gt M_c$ the relationship between SFR and $R_e$ diminishes. Low-mass galaxies above the mean of the SFMS have smaller radii, exhibit compact and centrally concentrated profiles resembling green valley (GV) and quiescent galaxies at the same mass, and have higher $M_{\text{H}_2}{/}M_\rm{H\,{\small I}}$. Conversely, those below the SFMS exhibit larger radii, lower densities, have no GV or quiescent counterparts at their mass and have lower $M_{\text{H}_2}/M_\rm{H\,{\small I}}$. The above data suggest two pathways for quenching low-mass galaxies, $M_\ast \le {}M_c$: a fast one that changes the morphology on the SFMS and a slow one that does not. Above $M_c$, galaxies below the SFMS resemble GV and quiescent galaxies structurally, implying that they undergo a structural transformation already within the SFMS. For these massive galaxies, CG are strongly bimodal, with SFMS galaxies exhibiting negative colour gradients, suggesting most star formation occurs in their outskirts, maintaining them within the SFMS.

The baryon cycle in modern cosmological hydrodynamical simulations

ABSTRACT In recent years, cosmological hydrodynamical simulations have proven their utility as key interpretative tools in the study of galaxy formation and evolution. In this work, we present a comparative analysis of the baryon cycle in three publicly available, leading cosmological simulation suites: EAGLE, IllustrisTNG, and SIMBA. While these simulations broadly agree in terms of their predictions for the stellar mass content and star formation rates of galaxies at $z\approx 0$, they achieve this result for markedly different reasons. In EAGLE and SIMBA, we demonstrate that at low halo masses ($M_{\rm 200c}\lesssim 10^{11.5}\, \mathrm{M}_{\odot }$), stellar feedback (SF)-driven outflows can reach far beyond the scale of the halo, extending up to $2\!-\!3\times R_{\rm 200c}$. In contrast, in TNG, SF-driven outflows, while stronger at the scale of the interstellar medium, recycle within the circumgalactic medium (within $R_{\rm 200c}$). We find that active galactic nucleus (AGN)-driven outflows in SIMBA are notably potent, reaching several times $R_{\rm 200c}$ even at halo masses up to $M_{\rm 200c}\approx 10^{13.5}\, \mathrm{M}_{\odot }$. In both TNG and EAGLE, AGN feedback can eject gas beyond $R_{\rm 200c}$ at this mass scale, but seldom beyond $2\!-\!3\times R_{\rm 200c}$. We find that the scale of feedback-driven outflows can be directly linked with the prevention of cosmological inflow, as well as the total baryon fraction of haloes within $R_{\rm 200c}$. This work lays the foundation to develop targeted observational tests that can discriminate between feedback scenarios, and inform subgrid feedback models in the next generation of simulations.

Efficient NIRCam Selection of Quiescent Galaxies at 3 < z < 6 in CEERS

Substantial populations of massive quiescent galaxies at z ≥ 3 challenge our understanding of rapid galaxy growth and quenching over short timescales. In order to piece together this evolutionary puzzle, more statistical samples of these objects are required. Established techniques for identifying massive quiescent galaxies are increasingly inefficient and unconstrained at z > 3. As a result, studies report that as much as 70% of quiescent galaxies at z > 3 may be missed from existing surveys. In this work, we propose a new empirical color selection technique designed to select massive quiescent galaxies at 3 ≲ z ≲ 6 using JWST NIRCam imaging data. We use empirically constrained galaxy spectral energy distribution (SED) templates to define a region in the F277W − F444W versus F150W − F277W color plane that captures quiescent galaxies at z > 3. We apply these color selection criteria to the Cosmic Evolution Early Release Science (CEERS) Survey and use SED fitting on sources in the region to identify 44 candidate z ≳ 3 quiescent galaxies. Over half of these sources are newly discovered and, on average, exhibit specific star formation rates of poststarburst galaxies. Most of these sources would not be discovered using canonical UVJ diagrams. We derive volume density estimates of n ∼ 1–4 × 10−5 Mpc−3 at 3 < z < 5, finding excellent agreement with existing reports on similar populations in the CEERS field. Thanks to NIRCam’s wavelength coverage and sensitivity, this technique provides an efficient tool to search for large samples of these rare galaxies.

CEERS: 7.7 μm PAH Star Formation Rate Calibration with JWST MIRI

We test the relationship between UV-derived star formation rates (SFRs) and the 7.7 μm polycyclic aromatic hydrocarbon luminosities from the integrated emission of galaxies at z ∼ 0–2. We utilize multiband photometry covering 0.2–160 μm from the Hubble Space Telescope, CFHT, JWST, Spitzer, and Herschel for galaxies in the Cosmic Evolution Early Release Science (CEERS) Survey. We perform spectral energy distribution (SED) modeling of these data to measure dust-corrected far-UV (FUV) luminosities, L FUV, and UV-derived SFRs. We then fit SED models to the JWST/MIRI 7.7–21 μm CEERS data to derive rest-frame 7.7 μm luminosities, L 770, using the average flux density in the rest-frame MIRI F770W bandpass. We observe a correlation between L 770 and L FUV, where logL770∝(1.27±0.04)logLFUV . L 770 diverges from this relation for galaxies at lower metallicities, lower dust obscuration, and for galaxies dominated by evolved stellar populations. We derive a “single-wavelength” SFR calibration for L 770 that has a scatter from model estimated SFRs (σ ΔSFR) of 0.24 dex. We derive a “multiwavelength” calibration for the linear combination of the observed FUV luminosity (uncorrected for dust) and the rest-frame 7.7 μm luminosity, which has a scatter of σ ΔSFR = 0.21 dex. The relatively small decrease in σ suggests this is near the systematic accuracy of the total SFRs using either calibration. These results demonstrate that the rest-frame 7.7 μm emission constrained by JWST/MIRI is a tracer of the SFR for distant galaxies to this accuracy, provided the galaxies are dominated by star formation with moderate-to-high levels of attenuation and metallicity.

The Contribution of Host Galaxy Properties in X-Ray Active Galactic Nuclei Clusters

In this study, the influence of host galaxy properties on X-ray active galactic nuclei (AGN) clusters was investigated using multiwavelength data. X-ray data from the eFEDS main catalog, optical and near-infrared data from the fourth data release of KiDS/VIKING, and mid-infrared data from WISE were utilized. By integrating these datasets and employing the CIGALE code, the star formation rate, luminosity, and stellar mass of the host galaxies were estimated. The analysis reveals significant associations between luminosity, stellar mass, and star formation rate, providing valuable insights into AGN activity. Furthermore, AGN clusters were compared with non-AGN clusters to uncover distinctive characteristics. AGN clusters exhibit differences in their population across various luminosity levels. Interestingly, a significant proportion of AGN clusters is concentrated in the middle range of luminosity (45-46 measured in logL&amp;lt;sub&amp;gt;(0.5-2.0 keV)&amp;lt;/sub&amp;gt;) for both low and high redshift classifications. Additionally, galaxies hosting AGNs detected in X-ray emission tend to fall within a specific range of stellar mass (10-11 measured in log(M&amp;lt;sub&amp;gt;⋆&amp;lt;/sub&amp;gt;(M&amp;lt;sub&amp;gt;⊚&amp;lt;/sub&amp;gt;)). This stellar mass range is populated by a substantial number of AGN galaxies, irrespective of their redshift classification. Moreover, a significant population of X-ray AGN is concentrated within the star formation rate range of 1.5-2.5 (expressed in log(M&amp;lt;sub&amp;gt;⊚&amp;lt;/sub&amp;gt; yr&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;)) in both low and high redshift regions. By analyzing the dependencies on luminosity, stellar mass, and star formation rate, this study provides valuable insights into the correlation and relationship between AGN clusters and their host galaxies. The comparison with non-AGN clusters and the integration of multiwavelength data from eFEDS, KiDS/VIKING, and WISE enhance the depth of analysis, contributing to a comprehensive evaluation of AGN clusters. These findings advance our understanding of the complex relationship between AGN clusters and host galaxy properties in the field of astrophysics.

Simultaneous derivation of galaxy physical properties with multimodal deep learning

ABSTRACT Upcoming telescopes and surveys will revolutionize our understanding of the Universe by providing unprecedented amounts of observations on extragalactic objects, which will require new tools complementing traditional astronomy methods, in particular machine learning techniques, and above all, deep architectures. In this study, we apply deep learning methods to estimate three essential parameters of galaxy evolution, i.e. redshift, stellar mass, and star formation rate (SFR), from a data set recently analysed and tailored to the Euclid context, containing simulated H-band images and tabulated photometric values. Our approach involved the development of a novel architecture called the FusionNetwork, combining two components suited to the heterogeneous data, ResNet50 for images, and a Multilayer Perceptron (MLP) for tabular data, through an additional MLP providing the overall output. The key achievement of our deep learning approach is the simultaneous estimation of the three quantities, previously estimated separately. Our model outperforms state-of-the-art methods: overall, our best FusionNetwork improves the fraction of correct SFR estimates from ∼70 to ∼80 per cent, while providing comparable results on redshift and stellar mass.