We present CO (J = 1−0) and/or CO (J = 2−1) spectroscopy for 31 galaxies selected from the ongoing Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, obtained with multiple telescopes. This sample is combined with CO observations from the literature to study the correlation of the CO luminosities ( ) with the mid-infrared luminosities at 12 ( ) and 22 μm ( ), as well as the dependence of the residuals on a variety of galaxy properties. The correlation with is tighter and more linear, but galaxies with relatively low stellar masses ( M _⊙) and blue colors ( and/or NUV − r ≲ 3) fall significantly below the mean – relation. We propose a new estimator of the CO (1−0) luminosity (and thus the total molecular gas mass M _mol) that is a linear combination of three parameters: , , and g − r. We show that, with a scatter of only 0.18 dex in log , this estimator provides unbiased estimates for galaxies of different properties and types. An immediate application of this estimator to a compiled sample of galaxies with only CO (J = 2−1) observations yields a distribution of the CO (J = 2−1) to CO (J = 1−0) luminosity ratios (R21) that agrees well with the distribution of real observations, in terms of both the median and the shape. Application of our estimator to the current MaNGA sample reveals a gas-poor population of galaxies that are predominantly early-type and show no correlation between molecular gas-to-stellar mass ratio and star formation rate, in contrast to gas-rich galaxies. We also provide alternative estimators with similar scatters, based on r- and/or z-band luminosities instead of . These estimators serve as cheap and convenient M _mol proxies to be potentially applied to large samples of galaxies, thus allowing statistical studies of gas-related processes of galaxies.

Understanding the circumgalactic medium (CGM) distribution of galaxies is the key to revealing the dynamical exchange of materials between galaxies and their surroundings. In this work, we use the DESI Early Data Release data set to investigate the cool CGM of galaxies (0.3 < z < 1.7) by stacking the spectra of background quasi-stellar objects to obtain the Mg ii absorption of foreground galaxies. The equivalent width of Mg ii absorption strongly correlates with stellar mass, with EW(Mg ii) ∝ M * 0.5 for star-forming galaxies with log M * / M ⊙ < 10 , but is independent of mass for galaxies above this mass. At a given stellar mass, EW(Mg ii) is larger for galaxies of higher star formation rate with an impact parameter less than 50 kpc, while showing little dependence on galaxy size. By studying the dependence on azimuthal angle, we find EW(Mg ii) is strongest at the direction near the minor axis for star-forming galaxies with log M * / M ⊙ < 10.0 , while no dependence on azimuthal angle is seen for luminous red galaxies. This indicates that the outflow associated with star formation enhances the Mg ii absorption. However, for galaxies with log M * / M ⊙ > 10.0 , the EW(Mg ii) at the minor axis is largely suppressed with respect to low-mass galaxies. This suggests that the competing processes, such as stellar feedback and gravity, play a key role in shaping the distribution of outflowing gas.

We complement the MALATANG sample of dense gas in nearby galaxies with archival observations of ¹²CO and its isotopologues to determine scaling relations between Wide-field Infrared Survey Explorer (WISE) 12 μm emission and molecular gas tracers at subkiloparsec scales. We find that 12 μm luminosity is more tightly correlated with ¹²CO than it is with ¹³CO or dense gas tracers. Residuals between predicted and observed ¹²CO are only weakly correlated with molecular gas mass surface density (Σ_mol) in regions where Σ_mol is very low (∼10 M _⊙ pc⁻²). Above this limit, the ¹²CO residuals show no correlations with physical conditions of molecular gas, while ¹³CO residuals depend on the gas optical depth and temperature. By analyzing differences from galaxy to galaxy, we confirm that the ¹²CO−12 μm relation is strong and statistically robust with respect to star-forming galaxies and active galactic nucleus hosts. These results suggest that WISE 12 μm emission can be used to trace total molecular gas instead of dense molecular gas, likely because polycyclic aromatic hydrocarbons (PAHs, a major contributor to WISE 12 μm emission) may be well mixed with the gas that is traced by ¹²CO. We propose that WISE 12 μm luminosity can be used to estimate molecular gas surface density for statistical analyses of the star formation process in galaxies.

We present the analysis of a comprehensive sample of 352 early-type galaxies using public data, to investigate the correlations between CO luminosities and mid-infrared luminosities observed by Wide-field Infrared Survey Explorer. We find strong correlations between both CO (1–0) and CO (2–1) luminosities and 12 μm luminosity, boasting a correlation coefficient greater than 0.9 and an intrinsic scatter smaller than 0.1 dex. The consistent slopes observed for the relationships of CO (1–0) and CO (2–1) suggest that the line ratio R21 lacks correlation with mid-infrared emission in early-type galaxies, which is significantly different from star-forming galaxies. Moreover, the slopes of L _CO(1−0)–L _{12 μm} and L _CO(2−1)–L _{12 μm} relations in early-type galaxies are steeper than those observed in star-forming galaxies. Given the absence of correlation with color, morphology, or specific star formation rate (sSFR), the correlation between deviations and the molecular gas mass surface density could be eliminated by correcting the possible 12 μm emission from old stars or adopting a systematically different α _CO. The latter, on average, is equivalent to adding a constant CO brightness density, specifically 2 . 8 − 0.6 + 0.8 [ K km s − 1 ] and 4 . 4 − 1.4 + 2.2 [ K km s − 1 ] for CO (1–0) and (2–1), respectively. These explorations will serve as useful tools for estimating the molecular gas content in gas-poor galaxies and understanding associated quenching processes.

In recent years, the rapid development of exoplanet research has provided us with an opportunity to better understand planetary systems in the universe and to search for signs of life. In order to further investigate the prevalence of habitable exoplanets and to validate planetary formation theories, as well as to comprehend planetary evolution, we have utilized confirmed exoplanet data obtained from the NASA Exoplanet Archive database, including data released by telescopes such as Kepler and TESS. By analyzing these data, we have selected a sample of planets around F, G, K, and M-type stars within a radius range of 1 to 20 $R_{\oplus }$ and with orbital periods ranging from 0.4 days to 400 days. Using the IDEM method based on these data, we calculated the overall formation rate, which is estimated to be 2.02%. Then, we use these data to analyze the relationship among planet formation rates, stellar metallicity, and stellar gravitational acceleration ($logg$). We firstly find that the formation rate of giant planets is higher around metal-rich stellars, but it inhibits the formation of gas giants when $logg$ > 4.5, yet the stellar metallicity seems to have no effect on the formation rate of smaller planets. Secondly, the host stellar gravitational acceleration affects the relationship between planet formation rate and orbital period. Thirdly, there is a robust power-law relationship between the orbital period of smaller planets and their formation rate. Finally, we find that, for a given orbital period, there is a positive correlation between the planet formation rate and the $logg$.

We investigate the multiphase gas surrounding QSOs traced by 33 absorption lines (e.g., Lyα, C iv, Fe ii, Mg ii, etc.) in the stacked spectra of background sources, using the Early Data Release from the Dark Energy Spectroscopic Instrument. Our analysis reveals that the equivalent width (W) of metal absorption lines decreases with increasing redshift, following an overall trend described by W ∝ (1 + z)^−4.0±2.7. Different species that trace multiphases of QSO-associated gas exhibit distinct evolutionary patterns. Additionally, the W of these absorption lines decreases with distance (D) from QSOs, which can be effectively characterized by a two-halo model. Compared to the projected two point correlation function of galaxies at similar redshifts, low-ionization ions exhibit similar clustering scales, while high-ionization ions show a significantly more extended spatial distribution. We also find that W _FeII/W _MgII increases toward lower redshifts, which can be attributed to evolving star formation histories and/or changes in initial mass function for galaxies. By leveraging multiple absorption tracers, we conduct the first comprehensive investigation of diffuse, multiphase gas from the circumgalactic medium to cosmological scales, offering new insights into baryon cycles and the transport of metals throughout cosmic time.