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Register a new userThe HI and stellar mass bivariate distribution of centrals and satellites for all, late- and early-type local galaxies
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Added by
Angel Ruben Calette
Publication date
2021
fields
Physics
and research's language is
English
Authors
A. R. Calette
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We characterize the conditional distributions of the HI gas-to-stellar mass ratio, $R_{HI}equiv M_{HI}/M_{ast}$, given the stellar mass, $M_{ast}$, of local galaxies from $M_{ast}sim 10^7$ to $10^{12}$ $M_{odot}$ separated into centrals and satellites as well as into late- and early-type galaxies (LTGs and ETGs, respectively). To do so, we use (1) the homogeneous eXtended GALEX Arecibo SDSS Survey, xGASS (Catinella et al. 2018), by re-estimating their upper limits and taking into account them in our statistical analysis; and (2) the results from a large compilation of HI data reported in Calette et al. (2018). We use the $R_{HI}$ conditional distributions combined with the Galaxy Stellar Mass Function to infer the bivariate $M_{HI}$ and $M_{ast}$ distribution of all galaxies as well of the late/early-type and central/satellite subsamples and their combinations. Satellites are on average less HI gas-rich than centrals at low and intermediate masses, with differences being larger for ETGs than LTGs; at $M_{ast}>3-5times 10^{10}$ $M_{odot}$ the differences are negligible. The differences in the HI gas content are much larger between LTGs and ETGs than between centrals and satellites. Our empirical HI Mass Function is strongly dominated by central galaxies at all masses. The empirically constrained bivariate $M_{HI}$ and $M_{ast}$ distributions presented here can be used to compare and constrain theoretical predictions as well as to generate galaxy mock catalogues.
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We report the bivariate HI- and H$_2$-stellar mass distributions of local galaxies in addition of an inventory of galaxy mass functions, MFs, for HI, H$_2$, cold gas, and baryonic mass, separately into early- and late-type galaxies. The MFs are determined using the HI and H$_2$ conditional distributions and the galaxy stellar mass function, GSMF. For the conditional distributions we use the compilation presented in Calette et al. 2018. For determining the GSMF from $M_{ast}sim3times10^{7}$ to $3times10^{12}$ $M_{odot}$, we combine two spectroscopic samples from the SDSS at the redshift range $0.0033<z<0.2$. We find that the low-mass end slope of the GSMF, after correcting from surface brightness incompleteness, is $alphaapprox-1.4$, consistent with previous determinations. The obtained HI MFs agree with radio blind surveys. Similarly, the H$_2$ MFs are consistent with CO follow-up optically-selected samples. We estimate the impact of systematics due to mass-to-light ratios and find that our MFs are robust against systematic errors. We deconvolve our MFs from random errors to obtain the intrinsic MFs. Using the MFs, we calculate cosmic density parameters of all the baryonic components. Baryons locked inside galaxies represent 5.4% of the universal baryon content, while $sim96$% of the HI and H$_2$ mass inside galaxies reside in late-type morphologies. Our results imply cosmic depletion times of H$_2$ and total neutral H in late-type galaxies of $sim 1.3$ and 7.2 Gyr, respectively, which shows that late type galaxies are on average inefficient in converting H$_2$ into stars and in transforming HI gas into H$_2$. Our results provide a fully self-consistent empirical description of galaxy demographics in terms of the bivariate gas--stellar mass distribution and their projections, the MFs. This description is ideal to compare and/or to constrain galaxy formation models.
We study the spatial distribution of faint satellites of intermediate redshift (0.1<z<0.8), early-type galaxies, selected from the GOODS fields. We combine high resolution HST images and state-of-the-art host subtraction techniques to detect satellites of unprecedented faintness and proximity to intermediate redshift host galaxies (up to 5.5 magnitudes fainter and as close as 0.5/2.5 kpc to the host centers). We model the spatial distribution of objects near the hosts as a combination of an isotropic, homogenous background/foreground population and a satellite population with a power law radial profile and an elliptical angular distribution. We detect a significant population of satellites, Ns =1.7 (+0.9,-0.8) that is comparable to the number of Milky Way satellites with similar host-satellite contrast.The average projected radial profile of the satellite distribution is isothermal, gamma_p= -1.0(+0.3,-0.4), which is consistent with the observed central mass density profile of massive early-type galaxies. Furthermore, the satellite distribution is highly anisotropic (isotropy is ruled out at a >99.99% confidence level). Defining phi to be the offset between the major axis of the satellite spatial distribution and the major axis of the host light profile, we find a maximum posterior probability of phi = 0 and |phi| less than 42 degrees at the 68% confidence level. The alignment of the satellite distribution with the light of the host is consistent with simulations, assuming that light traces mass for the host galaxy as observed for lens galaxies. The anisotropy of the satellite population enhances its ability to produce the flux ratio anomalies observed in gravitationally lensed quasars.
We investigate the origin of the relations between stellar mass and optical circular velocity for early-type (ETG) and late-type (LTG) galaxies --- the Faber-Jackson (FJ) and Tully-Fisher (TF) relations. We combine measurements of dark halo masses (from satellite kinematics and weak lensing), and the distribution of baryons in galaxies (from a new compilation of galaxy scaling relations), with constraints on dark halo structure from cosmological simulations. The principle unknowns are the halo response to galaxy formation and the stellar initial mass function (IMF). The slopes of the TF and FJ relations are naturally reproduced for a wide range of halo response and IMFs. However, models with a universal IMF and universal halo response cannot simultaneously reproduce the zero points of both the TF and FJ relations. For a model with a universal Chabrier IMF, LTGs require halo expansion, while ETGs require halo contraction. A Salpeter IMF is permitted for high mass (sigma > 180 km/s) ETGs, but is inconsistent for intermediate masses, unless V_circ(R_e)/sigma_e > 1.6. If the IMF is universal and close to Chabrier, we speculate that the presence of a major merger may be responsible for the contraction in ETGs while clumpy accreting streams and/or feedback leads to expansion in LTGs. Alternatively, a recently proposed variation in the IMF disfavors halo contraction in both types of galaxies. Finally we show that our models naturally reproduce flat and featureless circular velocity profiles within the optical regions of galaxies without fine-tuning.
[Abridged] Tight correlations between supermassive black hole (SMBH) mass ($M_{rm BH}$) and the properties of the host galaxy have useful implications for our understanding of the growth of SMBHs and evolution of galaxies. Here, we present newly observed correlations between $M_{rm BH}$ and the host galaxy total UV$-$ [3.6] color ($mathcal{C_{rm UV,tot}}$, Pearsons r = $0.6-0.7$) for a sample of 67 galaxies (20 early-type galaxies and 47 late-type galaxies) with directly measured $M_{rm BH}$ in the GALEX/S$^{4}$G survey. The colors are carefully measured in a homogeneous manner using the galaxies FUV, NUV and 3.6 $micron$ magnitudes and their multi-component structural decompositions in the literature. We find that more massive SMBHs are hosted by (early- and late-type) galaxies with redder colors, but the $M_{rm BH}- mathcal{C_{rm UV,tot}}$ relations for the two morphological types have slopes that differ at $sim 2 sigma$ level. Early-type galaxies define a red sequence in the $M_{rm BH}- mathcal{C_{rm UV,tot}}$ diagrams, while late-type galaxies trace a blue sequence. Within the assumption that the specific star formation rate of a galaxy (sSFR) is well traced by $L_{rm UV}/L_{rm 3.6}$, it follows that the SMBH masses for late-type galaxies exhibit a steeper dependence on sSFR than those for early-type galaxies. The $M_{rm BH}- mathcal{C_{rm UV,tot}}$ and $M_{rm BH}-L_{rm 3.6,tot}$ relations for the sample galaxies reveal a comparable level of vertical scatter in the log $M_{rm BH}$ direction, roughly $5%-27%$ more than the vertical scatter of the $M_{rm BH}-sigma$ relation. Our $M_{rm BH}- mathcal{C_{rm UV,tot}}$ relations suggest different channels of SMBH growth for early- and late-type galaxies, consistent with their distinct formation and evolution scenarios.
Recently a number of studies have found a similarity between the passive fraction of central and satellite galaxies when controlled for both stellar and halo mass. These results suggest that the quenching processes that affect galaxies are largely agnostic to central/satellite status, which contradicts the traditional picture of increased satellite quenching via environmental processes such as stripping, strangulation and starvation. Here we explore this further using the Galaxy And Mass Assembly (GAMA) survey which extends to ~2dex lower in stellar mass than SDSS, is more complete for closely-separated galaxies (>95% compared to >70%), and identifies lower-halo-mass groups outside of the very local Universe (M$_{mathrm{halo}}sim10^{12}$M$_{odot}$ at $0.1<z<0.2$). As far as possible we aim to replicate the selections, completeness corrections and central/satellite division of one of the previous studies but find clear differences between passive fractions of centrals and satellites. We also find that our passive fractions increase with both halo-to-satellite mass ratio and central-to-second rank mass ratio. This suggests that quenching is more efficient in satellites that are low-mass for their halo ($i.e$ at high halo-to-satellite mass ratio in comparison to low halo-to-satellite mass ratio) and are more likely to be passive in older groups - forming a consistent picture of environmental quenching of satellites. We then discuss potential explanations for the previously observed similarity, such as dependence on the group-finding method.
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