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Register a new userThe EDGE-CALIFA survey: The local and global relations between $Sigma_ast$ , $Sigma_{SFR}$ and $Sigma_{mol}$ that regulate star-formation
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Sebastian F. Sanchez
Publication date
2021
fields
Physics
and research's language is
English
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We present a new characterization of the relations between star-formation rate, stellar mass and molecular gas mass surface densities at different spatial scales across galaxies (from galaxy wide to kpc-scales). To do so we make use of the largest sample combining spatially-resolved spectroscopic information with CO observations, provided by the EDGE-CALIFA survey, together with new single dish CO observations obtained by APEX. We show that those relations are the same at the different explored scales, sharing the same distributions for the explored data, with similar slope, intercept and scatter (when characterized by a simple power-law). From this analysis, we propose that these relations are the projection of a single relation between the three properties that follows a distribution well described by a line in the three-dimension parameter space. Finally, we show that observed secondary relations between the residuals and the considered parameters are fully explained by the correlation between the uncertainties, and therefore have no physical origin. We discuss these results in the context of the hypothesis of self-regulation of the star-formation process.
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We present a multilinear analysis to determine the significant predictors of star formation in galaxies using the combined EDGE-CALIFA sample of galaxies. We analyze 1845 kpc-scale lines of sight across 39 galaxies with molecular line emission measurements from EDGE combined with optical IFU data drawn from CALIFA. We use the Least Absolute Shrinkage and Selection Operator (LASSO) to identify significant factors in predicting star formation rates. We find that the local star formation rate surface density is increased by higher molecular gas surface densities and stellar surface densities. In contrast, we see lower star formation rates in systems with older stellar populations, higher gas- and stellar-phase metallicities and larger galaxy masses. We also find a significant increase in star formation rate with galactocentric radius normalized by the disk scale length, which suggests additional parameters regulating star formation rate not explored in this study.
The $M_{BH}$ - $sigma_{star}$ relation is considered a result of co-evolution between the host galaxies and their super-massive black holes. For elliptical-bulge hosting inactive galaxies, this relation is well established, but there is still a debate whether active galaxies follow the same relation. In this paper, we estimate black hole masses for a sample of 19 local luminous AGNs (LLAMA) in order to test their location on the $M_{BH}$ - $sigma_{star}$ relation. Super-massive black hole masses ($M_{BH}$) were derived from the broad-line based relations for H$alpha$, H$beta$ and Pa$beta$ emission line profiles for the Type 1 AGNs. We compare the bulge stellar velocity dispersion ($sigma_{star}$) as determined from the Ca II triplet (CaT) with the dispersion measured from the near-infrared CO (2-0) absorption features for each AGN and find them to be consistent with each other. We apply an extinction correction to the observed broad line fluxes and we correct the stellar velocity dispersion by an average rotation contribution as determined from spatially resolved stellar kinematic maps. The H$alpha$-based black hole masses of our sample of AGNs were estimated in the range 6.34 $leq$ $log{M_{BH}}$ $leq$ 7.75 M$_odot$ and the $sigma_{star CaT}$ estimates range between 73 $leq$ $sigma_{star CaT}$ $leq$ 227 km s$^{-1}$. From the so-constructed $M_{BH}$ - $sigma_{star}$ relation for our Type 1 AGNs, we estimate the black hole masses for the Type 2 AGNs and the inactive galaxies in our sample. In conclusion, we find that our sample of local luminous AGNs is consistent with the $M_{BH}$ - $sigma_{star}$ relation of lower luminosity AGNs and inactive galaxies, after correcting for dust extinction and the rotational contribution to the stellar velocity dispersion.
We present the relation between the star formation rate surface density, $Sigma_{rm SFR}$, and the hydrostatic mid-plane pressure, P$_{rm h}$, for 4260 star-forming regions of kpc size located in 96 galaxies included in the EDGE-CALIFA survey covering a wide range of stellar masses and morphologies. We find that these two parameters are tightly correlated, exhibiting smaller scatter and strong correlation in comparison to other star-forming scaling relations. A power-law, with a slightly sub-linear index, is a good representation of this relation. Locally, the residuals of this correlation show a significant anti-correlation with both the stellar age and metallicity whereas the total stellar mass may also play a secondary role in shaping the $Sigma_{rm SFR}$ - P$_{rm h}$ relation. For our sample of active star-forming regions (i.e., regions with large values of H$alpha$ equivalent width), we find that the effective feedback momentum per unit stellar mass ($p_ast/m_ast$),measured from the P$_{rm h}$ / $Sigma_{rm SFR}$ ratio increases with P$_{rm h}$. The median value of this ratio for all the sampled regions is larger than the expected momentum just from supernovae explosions. Morphology of the galaxies, including bars, does not seem to have a significant impact in the $Sigma_{rm SFR}$ - P$_{rm h}$ relation. Our analysis suggests that self regulation of the $Sigma_{rm SFR}$ at kpc scales comes mainly from momentum injection to the interstellar medium from supernovae explosions. However, other mechanism in disk galaxies may also play a significant role in shaping the $Sigma_{rm SFR}$ at local scales. Our results also suggest that P$_{rm h}$ can be considered as the main parameter that modulates star formation at kpc scales, rather than individual components of the baryonic mass.
We present a re-calibration of the $M_{BH}-sigma_{star}$ relation, based on a sample of 16 reverberation-mapped galaxies with newly determined bulge stellar velocity dispersions ($sigma_{star}$) from integral-field spectroscopy (IFS), and a sample of 32 quiescent galaxies with publicly available IFS. For both samples, $sigma_{star}$ is determined via two different methods that are popular in the literature, and we provide fits for each sample based on both sets of $sigma_{star}$. We find the fit to the AGN sample is shallower than the fit to the quiescent galaxy sample, and that the slopes for each sample are in agreement with previous investigations. However, the intercepts to the quiescent galaxy relations are notably higher than those found in previous studies, due to the systematically lower $sigma_{star}$ measurements that we obtain from IFS. We find that this may be driven, in part, by poorly constrained measurements of bulge effective radius ($r_{e}$) for the quiescent galaxy sample, which may bias the $sigma_{star}$ measurements low. We use these quiescent galaxy parameterizations, as well as one from the literature, to recalculate the virial scaling factor $f$. We assess the potential biases in each measurement, and suggest $f=4.82pm1.67$ as the best currently available estimate. However, we caution that the details of how $sigma_{star}$ is measured can significantly affect $f$, and there is still much room for improvement.
We analyze the emission line profiles detected in deep optical spectra of quasars to derive the mass of their super-massive black holes (SMBH) following the single-epoch virial method. Our sample consists in 6 radio-loud quasars and 4 radio-quiet quasars. We carefully fit a broad and narrow Gaussian component for each emission line in both the H$beta$ (10 objects) and H$alpha$ regions (5 objects). A very good agreement of the derived SMBH masses, $M_{rm SMBH}$, is found using the fitted broad H$beta$ and H$alpha$ emission lines. We compare our $M_{rm SMBH}$ results with those found by previous studies. We study the relationship between the $M_{rm SMBH}$ of the quasar and the stellar velocity dispersion, $sigma_{*}$, of the host galaxy. We use the measured $M_{rm SMBH}$ and $sigma_{*}$ to investigate the $M_{rm SMBH}$ - $sigma_{*}$ relation for both the radio-loud and radio-quiet subsamples. Besides the scatter, we find a good agreement between radio-quiet quasars and AGN+quiescent galaxies and between radio-loud quasars and AGN. Our analysis does not support the hypothesis of using $sigma$([O III] $lambda$5007) as a surrogate for stellar velocity dispersions in high-mass, high-luminosity quasars. We also investigate the relationship between the 5 GHz radio-continuum luminosity, $L_{rm~5,GHz}$, of the quasar host galaxy with both $M_{rm SMBH}$ and $sigma_{*}$. We do not find any correlation between $L_{rm 5,GHz}$ and $M_{rm SMBH}$, although we observe a trend that galaxies with larger stellar velocity dispersions have larger $L_{rm 5,GHz}$. Using the results of our fitting for the narrow emission lines of [O III] $lambda$5007 and [N II] $lambda$6583 we estimate the gas-phase oxygen abundance of six quasars, being sub-solar in all cases.
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