scholarly journals Effect of the environment on star formation activity and stellar mass for star-forming galaxies in the COSMOS field

2020 ◽  
Vol 499 (1) ◽  
pp. 948-956
Author(s):  
S M Randriamampandry ◽  
M Vaccari ◽  
K M Hess
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Cosmic Time ◽  
Stellar Mass ◽  
Star Forming ◽  
Galaxy Environment ◽  
Stellar Masses ◽  
The Relationship

ABSTRACT We investigate the relationship between the environment and the galaxy main sequence (the relationship between stellar mass and star formation rate), as well as the relationship between the environment and radio luminosity ($P_{\rm 1.4\, GHz}$), to shed new light on the effects of the environment on galaxies. We use the VLA-COSMOS 3-GHz catalogue, which consists of star-forming galaxies and quiescent galaxies (active galactic nuclei) in three different environments (field, filament, cluster) and for three different galaxy types (satellite, central, isolated). We perform for the first time a comparative analysis of the distribution of star-forming galaxies with respect to the main-sequence consensus region from the literature, taking into account galaxy environment and using radio observations at 0.1 ≤ z ≤ 1.2. Our results corroborate that the star formation rate is declining with cosmic time, which is consistent with the literature. We find that the slope of the main sequence for different z and M* bins is shallower than the main-sequence consensus, with a gradual evolution towards higher redshift bins, irrespective of environment. We see no trends for star formation rate in either environment or galaxy type, given the large errors. In addition, we note that the environment does not seem to be the cause of the flattening of the main sequence at high stellar masses for our sample.

scholarly journals The Metal Abundances across Cosmic Time (MACT) Survey. III – The relationship between stellar mass and star formation rate in extremely low-mass galaxies

2020 ◽  
Vol 501 (2) ◽  
pp. 2231-2249 ◽  
Author(s):  
Kaitlyn Shin ◽  
Chun Ly ◽  
Matthew A Malkan ◽  
Sangeeta Malhotra ◽  
Mithi de los Reyes ◽  
...  
Keyword(s):  
Star Formation ◽  
Near Infrared ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Cosmic Time ◽  
Stellar Mass ◽  
Star Forming ◽  
Dependent Relation ◽  
Photometric Measurements ◽  
Stellar Masses

ABSTRACT Extragalactic studies have demonstrated that there is a moderately tight (≈0.3 dex) relationship between galaxy stellar mass (M⋆) and star formation rate (SFR) that holds for star-forming galaxies at M⋆ ∼ 3 × 108–1011 M⊙, i.e. the ‘star formation main sequence’. However, it has yet to be determined whether such a relationship extends to even lower mass galaxies, particularly at intermediate or higher redshifts. We present new results using observations for 714 narrow-band H α-selected galaxies with stellar masses between 106 and 1010 M⊙ (average of 108.2 M⊙) at z ≈ 0.07–0.5. These galaxies have sensitive ultraviolet (UV) to near-infrared photometric measurements and optical spectroscopy. The latter allows us to correct our H α SFRs for dust attenuation using Balmer decrements. Our study reveals that: (1) for low-SFR galaxies, our H α SFRs systematically underpredict compared to far-UV measurements, consistent with other studies; (2) at a given stellar mass (≈108 M⊙), log (specific SFR) evolves as A log (1 + z) with A = 5.26 ± 0.75, and on average, specific SFR increases with decreasing stellar mass; (3) the SFR–M⋆ relation holds for galaxies down to ∼106 M⊙ (∼1.5 dex below previous studies), and over lookback times of up to 5 Gyr, follows a redshift-dependent relation of log (SFR) ∝ α log (M⋆/M⊙) + β z with α = 0.60 ± 0.01 and β = 1.86 ± 0.07; and (4) the observed dispersion in the SFR–M⋆ relation at low stellar masses is ≈0.3 dex. Accounting for survey selection effects using simulated galaxies, we estimate that the true dispersion is ≈0.5 dex.

scholarly journals On the relationship between gas content, star formation, and global H i asymmetry of galaxies on the star-forming main-sequence

2021 ◽  
Vol 504 (2) ◽  
pp. 1989-1998
Author(s):  
Adam B Watts ◽  
Barbara Catinella ◽  
Luca Cortese ◽  
Chris Power ◽  
Sara L Ellison
Keyword(s):  
Star Formation ◽  
Atomic Hydrogen ◽  
Main Sequence ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Stellar Mass ◽  
Gas Content ◽  
Merger Activity ◽  
Star Forming ◽  
The Relationship

ABSTRACT Observations have revealed that disturbances in the cold neutral atomic hydrogen (H i) in galaxies are ubiquitous, but the reasons for these disturbances remain unclear. While some studies suggest that asymmetries in integrated H i spectra (global H i asymmetry) are higher in H i-rich systems, others claim that they are preferentially found in H i-poor galaxies. In this work, we utilize the Arecibo Legacy Fast ALFA (ALFALFA) and extended GALEX Arecibo SDSS Survey (xGASS) surveys, plus a sample of post-merger galaxies, to clarify the link between global H i asymmetry and the gas properties of galaxies. Focusing on star-forming galaxies in ALFALFA, we find that elevated global H i asymmetry is not associated with a change in the H i content of a galaxy, and that only the galaxies with the highest global H i asymmetry show a small increase in specific star formation rate (sSFR). However, we show that the lack of a trend with H i content is because ALFALFA misses the ‘gas-poor’ tail of the star-forming main-sequence. Using xGASS to obtain a sample of star-forming galaxies that is representative in both sSFR and H i content, we find that global H i asymmetric galaxies are typically more gas-poor than symmetric ones at fixed stellar mass, with no change in sSFR. Our results highlight the complexity of the connection between galaxy properties and global H i asymmetry. This is further confirmed by the fact that even post-merger galaxies show both symmetric and asymmetric H i spectra, demonstrating that merger activity does not always lead to an asymmetric global H i spectrum.

scholarly journals xGASS: the role of bulges along and across the local star-forming main sequence

2020 ◽  
Vol 493 (4) ◽  
pp. 5596-5605 ◽  
Author(s):  
Robin H W Cook ◽  
Luca Cortese ◽  
Barbara Catinella ◽  
Aaron Robotham
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
Formation Rate ◽  
Stellar Mass ◽  
Local Universe ◽  
Star Forming ◽  
Star Formation Activity ◽  
The Galaxy ◽  
Stellar Masses

ABSTRACT We use our catalogue of structural decomposition measurements for the extended GALEX Arecibo SDSS Survey (xGASS) to study the role of bulges both along and across the galaxy star-forming main sequence (SFMS). We show that the slope in the sSFR–M⋆ relation flattens by ∼0.1 dex per decade in M⋆ when re-normalizing specifice star formation rate (sSFR) by disc stellar mass instead of total stellar mass. However, recasting the sSFR–M⋆ relation into the framework of only disc-specific quantities shows that a residual trend remains against disc stellar mass with equivalent slope and comparable scatter to that of the total galaxy relation. This suggests that the residual declining slope of the SFMS is intrinsic to the disc components of galaxies. We further investigate the distribution of bulge-to-total ratios (B/T) as a function of distance from the SFMS (ΔSFRMS). At all stellar masses, the average B/T of local galaxies decreases monotonically with increasing ΔSFRMS. Contrary to previous works, we find that the upper envelope of the SFMS is not dominated by objects with a significant bulge component. This rules out a scenario in which, in the local Universe, objects with increased star formation activity are simultaneously experiencing a significant bulge growth. We suggest that much of the discrepancies between different works studying the role of bulges originate from differences in the methodology of structurally decomposing galaxies.

scholarly journals Spatially-resolved SFR in nearby disk galaxies using IFS data

2016 ◽  
Vol 11 (S321) ◽  
pp. 273-273
Author(s):  
C. Catalán-Torrecilla ◽  
A. Gil de Paz ◽  
A. Castillo-Morales ◽  
J. Méndez-Abreu ◽  
S. Pascual ◽  
...  
Keyword(s):  
Star Formation ◽  
Spatial Information ◽  
Formation Rate ◽  
Cosmic Time ◽  
Stellar Mass ◽  
Massive Galaxies ◽  
Star Forming ◽  
Spatially Resolved ◽  
Open Questions ◽  
Stellar Masses

AbstractExploring the spatial distribution of the star formation rate (SFR) in nearby galaxies is essential to understand their evolution through cosmic time. With this aim in mind, we use a representative sample that contains a variety of morphological types, the CALIFA Integral Field Spectroscopy (IFS) sample. Previous to this work, we have verified that our extinction-corrected Hα measurements successfully reproduce the values derived from other SFR tracers such as Hαobs + IR or UVobs + IR (Catalán-Torrecilla et al. 2015).Now, we go one step further applying 2-dimensional photometric decompositions (Méndez-Abreu et al. (2008), Méndez-Abreu et al. (2014)) over these datacubes. This method allows us to obtain the amount of SFR in the central part (bulge or nuclear source), the bar and the disk, separately. First, we determine the light coming from each component as the ratio between the luminosity in every component (bulge, bar or disk) and the total luminosity of the galaxy. Then, for each galaxy we multiply the IFS datacubes by these previous factors to recover the luminosity in each component. Finally, we derive the spectrum associated to each galaxy component integrating the spatial information in the weighted datacube using an elliptical aperture covering the whole galaxy.2D photometric decomposition applied over 3D datacubes will give us a more detailed understanding of the role that disks play in more massive galaxies. Knowing if the disks in more massive SF galaxies have on average a lower or higher level of star formation activity and how these results are affected by the presence of nuclear bars are still open questions that we can now solve. We describe the behavior of these components in the SFR vs. stellar mass diagram. In particular, we highlight the role of the disks and their contribution to both the integrated SFR for the whole galaxy and the SFR in the disk at different stellar masses in the SFR vs. stellar mass diagram together with their relative position to the star forming Main Sequence.

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

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.

scholarly journals Evolution of star formation rate–density relation over cosmic time in a simulated universe: the observed reversal reproduced

2019 ◽  
Vol 489 (1) ◽  
pp. 339-348 ◽  
Author(s):  
Ho Seong Hwang ◽  
Jihye Shin ◽  
Hyunmi Song
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Local Density ◽  
Formation Rate ◽  
Cosmic Time ◽  
Galaxy Cluster ◽  
Star Forming ◽  
Hydrodynamical Simulation ◽  
Density Relation ◽  
Stellar Masses

ABSTRACT We use the IllustrisTNG cosmological hydrodynamical simulation to study the evolution of star formation rate (SFR)–density relation over cosmic time. We construct several samples of galaxies at different redshifts from z = 2.0 to z = 0.0, which have the same comoving number density. The SFR of galaxies decreases with local density at z = 0.0, but its dependence on local density becomes weaker with redshift. At z ≳ 1.0, the SFR of galaxies increases with local density (reversal of the SFR–density relation), and its dependence becomes stronger with redshift. This change of SFR–density relation with redshift still remains even when fixing the stellar masses of galaxies. The dependence of SFR on the distance to a galaxy cluster also shows a change with redshift in a way similar to the case based on local density, but the reversal happens at a higher redshift, z ∼ 1.5, in clusters. On the other hand, the molecular gas fraction always decreases with local density regardless of redshift at z = 0.0–2.0 even though the dependence becomes weaker when we fix the stellar mass. Our study demonstrates that the observed reversal of the SFR–density relation at z ≳ 1.0 can be successfully reproduced in cosmological simulations. Our results are consistent with the idea that massive, star-forming galaxies are strongly clustered at high redshifts, forming larger structures. These galaxies then consume their gas faster than those in low-density regions through frequent interactions with other galaxies, ending up being quiescent in the local universe.

scholarly journals Strong dependence of Type Ia supernova standardization on the local specific star formation rate

2020 ◽  
Vol 644 ◽  
pp. A176
Author(s):  
M. Rigault ◽  
V. Brinnel ◽  
G. Aldering ◽  
P. Antilogus ◽  
C. Aragon ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Strong Dependence ◽  
Formation Rate ◽  
Stellar Mass ◽  
Host Galaxy ◽  
Type Ia ◽  
Galaxy Environment ◽  
Stellar Masses ◽  
Ia Supernovae

As part of an on-going effort to identify, understand and correct for astrophysics biases in the standardization of Type Ia supernovae (SN Ia) for cosmology, we have statistically classified a large sample of nearby SNe Ia into those that are located in predominantly younger or older environments. This classification is based on the specific star formation rate measured within a projected distance of 1 kpc from each SN location (LsSFR). This is an important refinement compared to using the local star formation rate directly, as it provides a normalization for relative numbers of available SN progenitors and is more robust against extinction by dust. We find that the SNe Ia in predominantly younger environments are ΔY = 0.163 ± 0.029 mag (5.7σ) fainter than those in predominantly older environments after conventional light-curve standardization. This is the strongest standardized SN Ia brightness systematic connected to the host-galaxy environment measured to date. The well-established step in standardized brightnesses between SNe Ia in hosts with lower or higher total stellar masses is smaller, at ΔM = 0.119 ± 0.032 mag (4.5σ), for the same set of SNe Ia. When fit simultaneously, the environment-age offset remains very significant, with ΔY = 0.129 ± 0.032 mag (4.0σ), while the global stellar mass step is reduced to ΔM = 0.064  ±  0.029 mag (2.2σ). Thus, approximately 70% of the variance from the stellar mass step is due to an underlying dependence on environment-based progenitor age. Also, we verify that using the local star formation rate alone is not as powerful as LsSFR at sorting SNe Ia into brighter and fainter subsets. Standardization that only uses the SNe Ia in younger environments reduces the total dispersion from 0.142  ±  0.008 mag to 0.120  ±  0.010 mag. We show that as environment-ages evolve with redshift, a strong bias, especially on the measurement of the derivative of the dark energy equation of state, can develop. Fortunately, data that measure and correct for this effect using our local specific star formation rate indicator, are likely to be available for many next-generation SN Ia cosmology experiments.

scholarly journals Deep learning for galaxy mergers in the galaxy main sequence

2019 ◽  
Vol 15 (S341) ◽  
pp. 104-108
Author(s):  
William J. Pearson ◽  
Lingyu Wang ◽  
James Trayford ◽  
Carlo E. Petrillo ◽  
Floris F. S. van der Tak
Keyword(s):  
Deep Learning ◽  
Star Formation ◽  
Main Sequence ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Stellar Mass ◽  
Galaxy Mergers ◽  
The Galaxy ◽  
Galaxy Population ◽  
Stellar Masses

AbstractStarburst galaxies are often found to be the result of galaxy mergers. As a result, galaxy mergers are often believed to lie above the galaxy main sequence: the tight correlation between stellar mass and star formation rate. Here, we aim to test this claim.Deep learning techniques are applied to images from the Sloan Digital Sky Survey to provide visual-like classifications for over 340 000 objects between redshifts of 0.005 and 0.1. The aim of this classification is to split the galaxy population into merger and non-merger systems and we are currently achieving an accuracy of 92.5%. Stellar masses and star formation rates are also estimated using panchromatic data for the entire galaxy population. With these preliminary data, the mergers are placed onto the full galaxy main sequence, where we find that merging systems lie across the entire star formation rate - stellar mass plane.

scholarly journals Variations in the slope of the resolved star-forming main sequence: a tool for constraining the mass of star-forming regions

2020 ◽  
Vol 493 (1) ◽  
pp. L87-L91 ◽  
Author(s):  
Maan H Hani ◽  
Christopher C Hayward ◽  
Matthew E Orr ◽  
Sara L Ellison ◽  
Paul Torrey ◽  
...  
Keyword(s):  
Star Formation ◽  
Time Scales ◽  
Main Sequence ◽  
Formation Rate ◽  
Stellar Mass ◽  
Star Forming ◽  
Star Forming Regions ◽  
Fitting Method ◽  
Averaging Time ◽  
Stellar Masses

ABSTRACT The correlation between galaxies’ integrated stellar masses and star formation rates (the ‘star formation main sequence’, SFMS) is a well-established scaling relation. Recently, surveys have found a relationship between the star formation rate (SFR) and stellar mass surface densities on kpc and sub-kpc scales (the ‘resolved SFMS’, rSFMS). In this work, we demonstrate that the rSFMS emerges naturally in Feedback In Realistic Environments 2 (FIRE-2) zoom-in simulations of Milky Way-mass galaxies. We make SFR and stellar mass maps of the simulated galaxies at a variety of spatial resolutions and star formation averaging time-scales and fit the rSFMS using multiple methods from the literature. While the absolute value of the SFMS slope (αMS) depends on the fitting method, the slope is steeper for longer star formation time-scales and lower spatial resolutions regardless of the fitting method employed. We present a toy model that quantitatively captures the dependence of the simulated galaxies’ αMS on spatial resolution and use it to illustrate how this dependence can be used to constrain the characteristic mass of star-forming clumps.

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