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High-speed trains running on ballasted tracks intensify the vibration of ballast layers to a greater extent than conventional passenger trains, bringing detrimental effects on train operations. The geogrid exhibits advantages in the performance improvement of a ballasted track; however, its stabilization effect in real railways under the action of train moving loads at high speeds remains unclear. Herein, full-scale model tests on a ballasted trackbed with and without geogrid stabilization were conducted, and a novel sequential loading system was adopted to apply the train moving loads equivalently onto sleepers of the ballasted track. In the tests, the highest train speeds were 300 km/h for the ballasted track without geogrid stabilization, and 360 km/h for the ballasted track with geogrid stabilization. To monitor the geogrid tension strain under train moving loads, distributed fiber Bragg grating sensors were mounted on the geogrid ribs. It was found that the maximum geogrid tension strain between neighboring sleepers induced by train traffic was 6 times larger than that beneath the sleepers. This observation provides useful information for the design of geogrid stabilization. Wireless SmartRocks were installed in the ballast layer to trace the motions of ballast particles, and the geogrid influence zone in the ballast layer was identified as being at least 15 cm above the geogrid. The dynamic stress at the subballast surface was decreased by about 49% in the stabilized trackbed. The testing results also showed that geogrid stabilization could reduce ballast breakage (Bg) from 14·9% to 2·5% and reduce the permanent settlement of ballast layer by 40%. The experimental results presented in the paper provide a benchmark for geogrid-stabilization modeling and will be referenced for the optimal design of ballasted tracks.

The correlation between the kinetic jet power Pjet, intrinsic γ-ray luminosity (Lint), and accretion (Ldisc) may reveal the underlying jet physics in various black hole systems. We study the relation between kinetic jet power, intrinsic γ-ray luminosity, and accretion by using a large sample of jetted active galactic nuclei (AGNs), including flat-spectrum radio quasars (FSRQs), BL Lacertae objects (BL Lacs), γ-ray narrow-line Seyfert 1 galaxies (γNLS1s), and radio galaxies. Our main results are as follows: (1) The slope indices of the relation between Pjet and Lint are 0.85 ± 0.01 for the whole sample, 0.70 ± 0.02 for the FSRQs, 0.83 ± 0.03 for the BL Lacs, 0.68 ± 0.11 for the γNLS1s, and 0.93 ± 0.09 for the radio galaxies, respectively. The jets in γNLS1s and radio galaxies almost follow the same Pjet–Lint correlation that was obtained for Fermi blazars. (2) The slope indices of the relation between Lint and Ldisc are 1.05 ± 0.02 for the whole sample, 0.94 ± 0.05 for the FSRQs, 1.14 ± 0.05 for the BL Lacs, and 0.92 ± 0.18 for the γNLS1s, respectively. The γNLS1s and radio galaxies almost also follow the Lint–Ldisc correlation derived for Fermi blazars. (3) The jet power is larger than the luminosity of accretion discs for almost all jetted AGNs. Jet power depends on both the Eddington ratio and black hole mass. We obtain log Pjet ∼ (1.00 ± 0.02)log Ldisc for the whole sample, which is consistent with the theoretically predicted coefficient. These results may imply that the jets of jetted AGNs are powered by the Blandford–Znajek mechanism.

Both theory and observations suggest that outflows driven by an active central supermassive black hole (SMBH) has a feedback effect on shaping the global properties of the host galaxy. However, whether feedback from the outflow is effective, and if so, whether it is positive or negative, has long been controversial. Here, using the latest catalog from the Sloan Digital Sky Survey (SDSS), we use the flux ratio of the [O II] to [Ne V] emission lines as a proxy to compare the star formation rate (SFR) in the hosts of quasars with different types of broad absorption lines (BALs): low-ionization (Lo)BAL, high-ionization (Hi)BAL, and non-BAL. We find that SFR decreases from LoBAL to HiBAL quasars, and then increases from HiBAL to non-BAL quasars. Assuming that the sequence of LoBAL to HiBAL to non-BAL represents evolution, our results are consistent with a quenching and subsequent rebound of star formation in quasar host galaxies. This phenomenon can be explained that the SFR is suppressed by the outflow, which then rebounds once the outflow disappears as the quasars evolve from HiBALs to non-BALs. Our result suggests that the quasar outflow has a negative global feedback on galaxy evolution., 19 pages, 4 figures and 2 tables in main text. Accepted by a peer-reviewed journal

Under the coronal magnetic field, we estimate the maximal jet power of the Blandford-\Znajek (BZ) mechanism, Blandford-\Payne (BP) mechanism, and hybrid model. The jet power of the BZ and Hybrid model mechanisms depends on the spin of a black hole, while the jet power of the BP mechanism does not depend on the spin of a black hole. At high black hole spin, the jet power of the hybrid model is greater than that of the BZ and BP mechanisms. We find that the jet power of almost all gamma-\ray narrow line Seyfert 1 galaxies (gamma-\NLS1s) can be explained by the hybrid model. However, one source with jet power 0.1~\1 Eddington luminosity can not be explained by the hybrid model. We suggest that the magnetic field dragged inward by the accretion disk with magnetization-\driven outflows may accelerate the jets in this gamma-\NLS1., 9 pages,6 figures,accepted for publication in MNRAS

Distance-redshift diagrams probe expansion history of the Universe. We show that the stellar mass-binding energy (massE) relation of galaxies proposed in our previous study offers a new distance ruler at cosmic scales. By using elliptical galaxies in the main galaxy sample of the Sloan Digital Sky Survey Data Release 7, we construct a distance-redshift diagram over the redshift range from 0.05 to 0.2 with the massE ruler. The best-fit dark energy density is 0.675+-0.079 for flat Lambda-CDM, consistent with those by other probes. At the median redshift of 0.11, the median distance is estimated to have a fractional error of 0.34%, much lower than those by supernova (SN) Ia and baryonic acoustic oscillation (BAO) and even exceeding their future capability at this redshift. The above low-z measurement is useful for probing dark energy that dominates at the late Universe. For a flat dark energy equation of state model (flat wCDM), the massE alone constrains w to an error that is only a factor of 2.2, 1.7 and 1.3 times larger than those by BAO, SN Ia, and cosmic microwave background (CMB), respectively., 8 pages, 5 figures, MNRAS in press. The cosmoSIS modules for the massE ruler is at https://astronomy.nju.edu.cn/DFS//file/2022/07/02/20220702161632756vbde28.zip

We present for the first time the timing and spectral analyses for a narrow-line Seyfert 1 galaxy, SBS 1353+564, using \it{XMM-Newton} and \it{Swift} multi-band observations from 2007 to 2019. Our main results are as follows: 1) The temporal variability of SBS 1353+564 is random, while the hardness ratio is relatively constant over a time span of 13 years; 2) We find a prominent soft X-ray excess feature below 2 keV, which cannot be well described by a simple blackbody component; 3) After comparing the two most prevailing models for interpreting the origin of the soft X-ray excess, we find that the relativistically smeared reflection model is unable to fit the data above 5 keV well and the X-ray spectra do not show any reflection features, such as the Fe K\alpha emission line. However, the warm corona model can obtain a good fitting result. For the warm corona model, we try to use three different sets of spin values to fit the data and derive different best-fitting parameter sets; 4) We compare the UV/optical spectral data with the extrapolated values of the warm corona model to determine which spin value is more appropriate for this source, and we find that the warm corona model with non-spin can sufficiently account for the soft X-ray excess in SBS 1353+564., Comment: 12 pages, 8 figures, accepted for publication in MNRAS

Using NOEMA and ALMA 3mm line scans, we measure spectroscopic redshifts of six new dusty galaxies at 3.56, based on template IR spectrum energy distribution (SED) from known submillimeter galaxies at z=4--6. Dust SED analyses explain the photo-z overestimate from seemingly cold dust temperatures (Td) and steep Rayleigh-Jeans (RJ) slopes, providing additional examples of cold dusty galaxies impacted by the Cosmic Microwave Background (CMB). We therefore study the general properties of the enlarged sample of 10 ``cold" dusty galaxies over 3.5~4, together with the severe impact of the CMB on their RJ observables, paving the way for the diagnostics of optically thick dust in the early universe. Conventional gas mass estimates based on RJ dust continuum luminosities implicitly assume an optically thin case, overestimating gas masses by a factor of 2--3 on average in compact dusty star-forming galaxies., Comment: Published version in A&A

Ultra-diffuse galaxies (UDGs) are as faint as dwarf galaxies but whose sizes are similar to those of spiral galaxies. A variety of formation mechanisms have been proposed, some of which could result in different disk thicknesses. In this study, we measure the radial profile of the HI scale height (h_g) and flaring angle (h_g/R) of AGC 242019 through the joint Poisson-Boltzmann equation based on its well spatially-resolved HI gas maps. The mean HI scale height of AGC 242019 is \approx 537.15 \pm 89.4 pc, and the mean flaring angle is \approx 0.19 \pm 0.03. As a comparison, we also derive the disk thickness for a sample of 14 dwarf irregulars. It is found that the HI disk of AGC 242019 has comparable thickness to dwarfs. This suggests that AGC 242019 is unlikely to experience much stronger stellar feedback than dwarf galaxies, which otherwise leads to a thicker disk for this galaxy., Comment: 9 pages, 7 figures. Accepted for publication in MNRAS

Both Galactic and extragalactic studies on star formation suggest that stars form directly from dense molecular gas. To trace such high volume density gas, HCN and HCO+ J=1-0 have been widely used for their high dipole moments, relatively high abundances, and often being the strongest lines after CO. However, HCN and HCO+ J=1-0 emission could be arguably dominated by the gas components at low volume densities. HCN J=2-1 and HCO+ J=2-1, with more suitable critical densities and excitation requirements, would trace typical dense gas closely related to star formation. Here we report new observations of HCN J=2-1 and HCO+ J=2-1 towards 17 nearby infrared-bright galaxies with the APEX 12-m telescope. The correlation slopes between luminosities of HCN J=2-1, and HCO+ J=2-1 and total infrared emission are 1.03 +- 0.05 and 1.00 +- 0.05, respectively. The correlations of their surface densities, normalised with the area of radio/sub-millimeter continuum, show even tighter relations (Slopes: 0.99 +- 0.03 and 1.02 +- 0.03). The eight AGN-dominated galaxies show no significant difference from the eleven star-formation dominated galaxies in above relations. The average HCN/HCO+ ratios are 1.15 +- 0.26 and 0.98 +- 0.42 for AGN-dominated and star-formation dominated galaxies, respectively, without obvious dependencies on infrared luminosity, dust temperature, or infrared pumping. The Magellanic Clouds roughly follow the same correlations, expanding to eight orders of magnitude. On the other hand, ultra-luminous infrared galaxies with active galactic nucleus (AGN) systematically lay above the correlations, indicating potential biases introduced by AGNs., 28 pages, 12 figures, 6 tables

One of the most prominent features of galaxy clusters is the presence of a dominant population of massive ellipticals in their cores. Stellar archaeology suggests that these gigantic beasts assembled most of their stars in the early Universe via starbursts. However, the role of dense environments and their detailed physical mechanisms in triggering starburst activities remain unknown. Here we report spatially resolved Atacama Large Millimeter/submillimeter Array (ALMA) observations of the CO $J= 3-2$ emission line, with a resolution of about 2.5 kiloparsecs, toward a forming galaxy cluster core with starburst galaxies at $z=2.51$. In contrast to starburst galaxies in the field often associated with galaxy mergers or highly turbulent gaseous disks, our observations show that the two starbursts in the cluster exhibit dynamically cold (rotation-dominated) gas-rich disks. Their gas disks have extremely low velocity dispersion ($\sigma_{\mathrm{0}} \sim 20-30$ km s$^{-1}$), which is three times lower than their field counterparts at similar redshifts. The high gas fraction and suppressed velocity dispersion yield gravitationally unstable gas disks, which enables highly efficient star formation. The suppressed velocity dispersion, likely induced by the accretion of corotating and coplanar cold gas, might serve as an essential avenue to trigger starbursts in massive halos at high redshifts., Comment: 19 pages, 14 figures, 3 tables. Accepted for publication in A&A

With increasing train speed and wheel axle load, severe vibrations can occur in a ballasted trackbed, thereby accelerating the degradation of the ballast particles and ultimately causing excessive settlement. To gain insights into the long-term trackbed behavior and the ballast degradation evolution, a full-scale ballasted track experiment with eight sleepers was designed and tested on a validated physical model test platform (ZJU-iHSRT). Sieving analysis together with computer-aided ballast morphology analysis were adopted to quantify the ballast degradation in terms of both the ballast particle size and morphological evolution, after every 100,000 train carriages. Various sensors were installed at key locations in the trackbed to record the dynamic stress responses, vibration velocities and deformations under train moving loads for up to 500,000 train carriages in total. The movements of individual particles inside the ballast layer were also captured using “SmartRock” wireless sensors. The dynamic soil stresses and vibration velocities in the trackbed all peaked at the locations underneath the rail seat and decayed with the distance away from the rail seat. Severe ballast degradation occurred in both particle sizes and morphological properties, with the ballast particles in the middle zone under the sleeper suffering a greater breakage due to the stronger confinement. The long-term train loads densified the ballast layer, both through particle rearrangement and particle breakage filling the voids in the ballast bed, resulting in a reduction in the stresses and vibrations. The amplitudes of the vertical stresses and the vibration velocities in the trackbed around the rail seat were reduced by over 25% and 38% respectively after 500,000 train loading carriages. The ballast particle shape became more compact after the test, with larger diameter and more Platy, Bladed and Elongate shapes found to be the more likely to degrade. Over 50% of the permanent settlement of the ballasted trackbed resulted from the ballast layer deformation, and the increase in the train speed intensified particle movements away from the sleeper in the lateral and longitudinal directions in the ballast layer and accelerated the development of the accumulated settlement, while the increase in the axle load caused the ballast breakage index (BBI) to rise dramatically by over 50% and contributed significantly to a greater settlement.

Black hole feedback has been widely implemented as the key recipe to quench star formation in massive galaxies in modern semi-analytic models and hydrodynamical simulations. As the theoretical details surrounding the accretion and feedback of black holes continue to be refined, various feedback models have been implemented across simulations, with notable differences in their outcomes. Yet, most of these simulations have successfully reproduced some observations, such as stellar mass function and star formation rate density in the local Universe. We use the recent observation on the change of neutral hydrogen gas mass (including both ${\rm H_2}$ and ${\rm HI}$) with star formation rate of massive central disc galaxies as a critical constraint of black hole feedback models across several simulations. We find that the predictions of IllustrisTNG agree with the observations much better than the other models tested in this work. This favors IllustrisTNG's treatment of active galactic nuclei - where kinetic winds are driven by black holes at low accretion rates - as more plausible amongst those we test. In turn, this also indirectly supports the idea that the massive central disc galaxy population in the local Universe was likely quenched by AGN feedback., Comment: 15 pages, 3+4 figures, accepted for publication in ApJ

Context. The physical mechanisms driving starbursts and quenching in less massive (M* ≤ 1010 M⊙) galaxies are unclear. The merger is one of the inescapable processes referred to as both starburst and quenching in massive galaxies. However, the effects of the merger on star formation in dwarf galaxies and their evolution are still uncertain. Aims. We aim to explore how star formation in dwarf galaxies is both triggered and quenched by studying metal-poor gas-rich dwarf mergers based on multi-band observations at a spatial resolution of ∼460 pc. Methods. We use archival data of Atacama Large Millimetre Array (Band 3 and 8) and Very Large Telescope/Multi Unit Spectroscopic Explorer to map CO(J = 1–0), [CI](3P1–3P0), and Hα emission in one of the most extreme merging starburst dwarf galaxies, Haro 11. Results. We find the molecular gas is assembled around the central two star-forming regions (knots B and C). The molecular and ionized gas and stellar components show complex kinematics, indicating that the gas is probably at a combined stage of collision of clouds and feedback from star formation. The peak location and distribution of [CI](1–0) closely coincide with the CO(1–0) emission, meaning that it might trace the same molecular gas as CO in such a dwarf merger starburst galaxy. The enhancement of line ratios (∼0.5) of [CI]/CO around knot C is probably generated by the dissociation of CO molecules by cosmic rays and far-ultraviolet photons. Globally, Haro 11 and its star-forming regions share similar star formation efficiency (SFE) to the high-z starburst galaxies or the clumps in nearby ultraluminous infrared galaxies. Conclusions. Given the high SFE, the high specific star formation rate, small stellar mass, low metallicity, and deficient HI gas, Haro 11 could be an analog of a high-z dwarf starburst and the potential progenitor of the nearby less massive elliptical galaxies. The significantly smaller turbulent pressure and viral parameter is probably triggering the intense starbursts. We predict that Haro 11 will quench at M* ≤ 8.5 × 109 M⊙.

We presented the multiwavelength analysis of a heavily obscured active galactic nucleus (AGN) in NGC 449. We first constructed a broadband X-ray spectrum using the latest NuSTAR and XMM-Newton data. Its column density ($\simeq 10^{24} \rm{cm}^{-2}$) and photon index ($\Gamma\simeq 2.4$) were reliably obtained by analyzing the broadband X-ray spectrum. However, the scattering fraction and the intrinsic X-ray luminosity could not be well constrained. Combined with the information obtained from the mid-infrared (mid-IR) spectrum and spectral energy distribution (SED) fitting, we derived its intrinsic X-ray luminosity ($\simeq 8.54\times 10^{42} \ \rm{erg\ s}^{-1}$) and scattering fraction ($f_{\rm{scat}}\simeq 0.26\%$). In addition, we also derived the following results: (1). The mass accretion rate of central AGN is about $2.54 \times 10^{-2} \rm{M}_\odot\ \rm{yr}^{-1}$, and the Eddington ratio is $8.39\times 10^{-2}$; (2). The torus of this AGN has a high gas-to-dust ratio ($N_{\rm H}/A_{\rm V}=8.40\times 10^{22}\ \rm{cm}^{-2}\ \rm{mag}^{-1}$); (3). The host galaxy and the central AGN are both in the early stage of co-evolution., Comment: 12 pages, 5 figures, 3 tables, Accepted to PASP

The physical parameters of galaxies and/or AGNs can be derived by fitting their multi-band spectral energy distributions (SEDs). By using CIGALE code, we perform multi-band SED fitting (from ultraviolet to infrared) for 791 X-ray sources (518 AGNs and 273 normal galaxies) in the 7 Ms Chandra Deep Field-south survey (CDFS). We consider the contributions from AGNs and adopt more accurate redshifts than published before. Therefore, more accurate star formation rates (SFRs) and stellar masses (M$_*$) are derived. We classify the 518 AGNs into type-I and type-II based on their optical spectra and their SEDs. Moreover, six AGN candidates are selected from the 273 normal galaxies based on their SEDs. Our main results are as follows: (1) the host galaxies of AGNs have larger M$_*$ than normal galaxies, implying that AGNs prefer to host in massive galaxies; (2) the specific star formation rates (sSFRs) of AGN host galaxies are different from those of normal galaxies, suggesting that AGN feedback may play an important role in the star formation activity; (3) we find that the fraction of optically obscured AGNs in CDFS decreases with the increase of intrinsic X-ray luminosity, which is consistent with previous studies;(4) the host galaxies of type-I AGNs tend to have lower M$_*$ than type-II AGNs, which may suggest that dust in the host galaxy may also contribute to the optical obscuration of AGNs., Comments: 17 Pages, 16 Figures, 5 tables. Accepted for publication in MNRAS

Very little work has been done on star formation in dwarf lenticular galaxies (S0s). We present 2D spectroscopic and millimetre observations made by the Centro Astronómico Hispano Alemán (CAHA) 3.5-m optical and Institut de Radioastronomie Millimétrique (IRAM) 30-m millimetre telescopes, respectively, for a sample of four dwarf S0 galaxies with multiple star formation regions in the field environment. We find that, although most of the sources deviate from the star-forming main-sequence relation, they all follow the Kennicutt-Schmidt law. After comparing the stellar and Hα kinematics, we find that the velocity fields of both stars and ionized gas show no regular motion and the velocity dispersions of both stars and ionized gas are low in regions with high star formation, suggesting that these star-forming S0 galaxies still have significant rotation. This view can be supported by the result that most of these dwarf S0 galaxies are classified as fast rotators. The ratio of the average atomic gas mass to stellar mass ($\sim 47{{\ \rm per\ cent}}$) is much greater than that of the molecular gas mass to stellar mass ($\sim 1{{\ \rm per\ cent}}$). In addition, gas-phase metallicities in star-forming regions are lower than those of non-star-forming regions. These results indicate that extended star formation may originate from the combination of abundant atomic hydrogen, a long dynamic time-scale, and a low-density environment. © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society., This work is supported by the National Key Research and Development Program of China (No. 2017YFA0402703) and by the National Natural Science Foundation of China (No. 11733002). In addition, we acknowledge the support of the staff from CAHA and IRAM-30 m. RGB acknowledges additional financial support from the State Agency for Research of the Spanish (MCIU) through the Center of Excellence Severo Ochoa award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709), grants PID2019-109067GB-I00 (MCIU), and P18-FRJ-2595 (Junta de Andalucía). We are grateful for the support of the scientific research fund of Jiangsu Second Normal University (927801/032). N.D acknowledges financial support from the National Natural Science Foundation of China grant 12103022 and the scientific research fund of Yunnan Provincial Education Department (2021J0715).

For the ballasted railway, under the action of dynamic load caused by the train traffic, the higher loading frequency and amplitude may eventually result in excessive settlement in the ballast, thereby reducing the passengers’ comfort and even affecting the safety of train operation. To study the influence of train traffic load with higher frequency and amplitude imposed on the ballast and the employment of geogrid, ballasted railway model test on the cumulative settlement of geogrid-reinforced ballast under different train loads such as high-speed and heavy axle load and different types of geogrid reinforcement conditions, and triaxial test results of ballast specimens with and without geogrid under different confining pressures are discussed in this paper. The cumulative settlement and stress distribution of the ballast layer, the sleeper vibration, and the strain of geogrid of ballasted subgrade in the model tests under different train loads and geogrid reinforcement conditions are analyzed throughout the test, to explore the effect of geogrid and its working mechanism. Multiple groups of experimental results of axial strain, circumferential strain, and volumetric strain with various confining pressure in the triaxial tests are also compared and studied in this paper. These tests indicated that the installation of geogrid depresses the development of volumetric deformation and effectively increases the peak stress values in the ballast layer. The loading frequency and amplitude also play a vital role in the settlement development and degradation of ballasted subgrade at the same time.

This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI., Lenticular galaxies (S0s) were considered mainly as passive evolved spirals due to environmental effects for a long time; however, most S0s in the field cannot fit into this common scenario. In this work, we study one special case, Sloan Digital Sky Survey J120237.07+642235.3 (PGC 38025), a star-forming field S0 galaxy with an off-nuclear blue core. We present optical integral field spectroscopic observation with the 3.5 meter telescope at Calar Alto Observatory, and high-resolution millimeter observation with the NOrthern Extended Millimeter Array. We estimated the star formation rate (SFR = 0.446 M o? yr-1) and gaseous metallicity (12 + log(O/H) = 8.42) for PGC 38025, which follows the star formation main sequence and stellar mass-metallicity relation. We found that the ionized gas and cold molecular gas in PGC 38025 show the same spatial distribution and kinematics, while rotating misaligned with stellar component. The off-nuclear blue core is locating at the same redshift as PGC 38025 and its optical spectrum suggest it is H ii region. We suggest that the star formation in PGC 38025 is triggered by a gas-rich minor merger, and the off-nuclear blue core might be a local star formation happened during the accretion/merger process. © 2021. The Author(s)., This work is supported by the National Key Research and Development Program of China (No. 2017YFA0402703) and by the National Natural Science Foundation of China (No. 11733002). This work is based on observations carried out with the IRAM NOrthern Extended Millimeter Array. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). In addition, we acknowledge the supports of the staffs from CAHA and NOEMA, especially Orsolya Feher. R.G.B. acknowledges financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofsica de Andalucia (SEV-2017-0709) and grants PID2019-109067GB-I00 and P18FRJ-2595.

In this study we demonstrate that stellar masses of galaxies (Mstar) are universally correlated through a double power law function with the product of the dynamical velocities (Ve) and sizes to one-fourth power (Re^0.25) of galaxies, both measured at the effective radii. The product VeRe^0.25 represents the fourth root of the total binding energies within effective radii of galaxies. This stellar mass-binding energy correlation has an observed scatter of 0.14 dex in log(VeRe^0.25) and 0.46 dex in log(Mstar). It holds for a variety of galaxy types over a stellar mass range of nine orders of magnitude, with little evolution over cosmic time. A toy model of self-regulation between binding energies and supernovae feedback is shown to be able to reproduce the observed slopes, but the underlying physical mechanisms are still unclear. The correlation can be a potential distance estimator with an uncertainty of 0.2 dex independent of the galaxy type., Comment: 10 pages, 7 figures, MNRAS in press

To investigate star-forming activities in early-type galaxies, we select a sample of 52 star-forming S0 galaxies (SFS0s) from the SDSS-IV MaNGA survey. We find that SFS0s have smaller stellar mass compared to normal S0s in MaNGA. After matching the stellar mass to select the control sample, we find that the mean S\'{e}rsic index of SFS0s' bulges (1.76$\pm$0.21) is significantly smaller than that of the control sample (2.57$\pm$0.20), suggesting the existence of a pseudo bulge in SFS0s. After introducing the environmental information, SFS0s show smaller spin parameters in the field than in groups, while the control sample has no obvious difference in different environments, which may suggest different dynamical processes in SFS0s. Furthermore, with derived N/O and O/H abundance ratios, SFS0s in the field show nitrogen enrichment, providing evidence for the accretion of metal-poor gas in the field environment. To study the star formation relation, we show that the slope of the spatially resolved star formation main sequence is nearly 1.0 with MaNGA IFU data, confirming the self-regulation of star formation activities at the kpc scales., Comment: 9 pages, 9 figures, MNRAS accepted

Using the integral field unit (IFU) data from Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, we collect a sample of 36 star forming galaxies that host galactic-scale outflows in ionized gas phase. The control sample is matched in the three dimensional parameter space of stellar mass, star formation rate and inclination angle. Concerning the global properties, the outflows host galaxies tend to have smaller size, more asymmetric gas disk, more active star formation in the center and older stellar population than the control galaxies. Comparing the stellar population properties along axes, we conclude that the star formation in the outflows host galaxies can be divided into two branches. One branch evolves following the inside-out formation scenario. The other locating in the galactic center is triggered by gas accretion or galaxy interaction, and further drives the galactic-scale outflows. Besides, the enhanced star formation and metallicity along minor axis of outflows host galaxies uncover the positive feedback and metal entrainment in the galactic-scale outflows. Observational data in different phases with higher spatial resolution are needed to reveal the influence of galactic-scale outflows on the star formation progress in detail., Comment: 11 pages, 6 figures, accepted for publication in MNRAS

Star formation and quenching are two of the most important processes in galaxy formation and evolution. We explore in the local Universe the interrelationships among key integrated galaxy properties, including stellar mass $M_*$, star formation rate (SFR), specific SFR (sSFR), molecular gas mass $M_{\rm H_2}$, star formation efficiency (SFE) of the molecular gas and molecular gas to stellar mass ratio $\mu$. We aim to identify the most fundamental scaling relations among these key galaxy properties and their interrelationships. We show the integrated $M_{\rm H_2}$-SFR, SFR-$M_*$ and $M_{\rm H_2}$-$M_*$ relation can be simply transformed from the $\mu$-sSFR, SFE-$\mu$ and SFE-sSFR relation, respectively. The transformation, in principle, can increase or decrease the scatter of each relation. Interestingly, we find the latter three relations all have significantly smaller scatter than the former three corresponding relations. We show the probability to achieve the observed small scatter by accident is extremely close to zero. This suggests that the smaller scatters of the latter three relations are driven by a more fundamental physical connection among these quantities. We then show the large scatters in the former relations are due to their systematic dependence on other galaxy properties, and on star formation and quenching process. We propose the sSFR-$\mu$-SFE relation as the Fundamental Formation Relation (FFR), which governs the star formation and quenching process, and provides a simple framework to study galaxy evolution. Other scaling relations, including integrated Kennicutt-Schmidt law, star-forming main sequence and molecular gas main sequence, can all be derived from the FFR., Comment: This is the revised version accepted for publication in ApJ

Even in deep X-ray surveys, Compton-thick active galactic nuclei (CT AGNs, ${\rm N_H} \geqslant 1.5~\times~10^{24}~{\rm cm}^{-2}$) are difficult to be identified due to X-ray flux suppression and their complex spectral shape. However, the study of CT AGNs is vital for understanding the rapid growth of black holes and the origin of cosmic X-ray background. In the local universe, the fraction of CT AGNs accounts for 30% of the whole AGN population. We may expect a higher fraction of CT AGNs in deep X-ray surveys, however, only 10% of AGNs have been identified as CT AGNs in the 7 Ms \textit{Chandra} Deep Field-South (CDFS) survey. In this work, we select 51 AGNs with abundant multi-wavelength data. Using the method of the mid-infrared (mid-IR) excess, we select hitherto unknown 8 CT AGN candidates in our sample. Seven of these candidates can confirm as CT AGN based on the multi-wavelength identification approach, and a new CT AGN (XID 133) is identified through the mid-IR diagnostics. We also discuss the X-ray origin of these eight CT AGNs and the reason why their column densities were underestimated in previous studies. We find that the multi-wavelength approaches of selecting CT AGNs are highly efficient, provided the high quality of observational data. We also find that CT AGNs have a higher Eddington ratio than non-CT AGNs, and that both CT AGNs and non-CT AGNs show similar properties of host galaxies., 13 pages, 6 figures, 3 tables, accepted for publication in ApJ

We present here a systematic study on the mechanism of the long/short timescale variability and the origin of soft X-ray excess for narrow-line Seyfert 1 galaxies (NLSy1s) based on the multi-epoch multi-band observations of theSwifttelescope. The main results are as follows: (1) The ensemble structure functions of radio-quiet NLSy1s in the optical, ultraviolet, and X-ray bands all show a unique double ‘S’ structure. The structural feature reveals that the long and short timescale variability of radio-quiet NLSy1s could be generated by the accretion fluctuation propagation mechanism and the X-ray reprocessing mechanism, respectively, which together cause the complex random light variability. (2) Radio-quiet NLSy1s exhibit significant soft X-ray excess features in their X-ray spectra, but the relative strength of the soft X-ray excess (R) and the power-law spectral index (Γ) do not show a significant positive correlation, unlike what is seen in broad-line Seyfert 1 galaxies (BLSy1s), suggesting that NLSy1s and BLSy1 have different soft X-ray excess mechanisms. After combining the correlation analysis results of model parameters for individual sources at different flux states with the findings in previous work based onXMM-Newtonand Suzaku data, we propose that the origin of the soft X-ray excess of NLSy1s prefers the relativistically smeared reflection scenario.

Comparing to the inactive and gas-poor normal lenticular galaxies (S0s) in the local universe, we study a barred star-forming S0 galaxy, PGC 34107, which has been observed by the Centro Astron\'{o}mico Hispano Alem\'{a}n (CAHA) 3.5-m telescope and the Northern Extended Millimeter Array (NOEMA). The spatially resolved ionized gas and molecular gas traced by $^{12}$CO(1-0), hereafter CO(1-0), show the similar distribution and kinematics to the stellar component with an off-center star-forming region, $\sim$380 pc away from the center. The resolved kinematics of molecular CO(1-0) emission reveals that there is a blueshifted (redshifted) velocity component on the receding (approaching) side of the galaxy along the stellar bar. This might provide a plausible evidence of non-circular motion, such as the bar-induced molecular gas inflow. The velocity of molecular gas inflow decreases with approaching towards the peak of the off-center star formation in the north, which might be associated with the inner Lindblad resonance (ILR). In addition to CO(1-0), we also detect the isotopic line of $^{13}$CO(1-0). Most $\rm H\alpha$, CO(1-0) and $^{13}$CO(1-0) emissions are concentrated on this northern star-forming region. We find that PGC 34107 follows the local stellar mass-metallicity relation, star-forming main sequence, and the Kennicutt-Schmidt law. The resolved and integrated molecular gas main sequence suggest that there is a higher gas fraction in the galaxy central region, which supports a scenario that the bar-induced gas reservoir provides the raw material, and subsequently triggers the central star formation., Comment: 18pages, 13figures, 1table, accepted by ApJ

The detection of inflows at the scale of the dusty torus and smaller is crucial for investigating the process of supermassive black hole (SMBH) accretion. However, only a few cases of inflowing gas at small scales have been reported through redshifted broad absorption lines so far. Here we report nine redshifted narrow absorption lines (NALs) of Mg+ions with inflowing speeds of 1071–1979 km s−1, which are likely along the directions close to the axes of accretion disks. The quasars showing inflowing Mg IINALs have, on average, slightly smaller Eddington ratios than the sources with outflowing Mg IINALs. The upper limits on the locations of the detected NALs are at parsec scale, that is, the distance from dusty tori to their central SMBHs. One possible origin of these infalling NALs is from dusty tori. However, these infalling NALs could also be naturally explained by chaotic cold accretion resulting from the nonlinear interaction of active galactic nucleus (AGN) jets with the interstellar medium (ISM), and these cold gaseous blobs may originally precipitate in metal-rich trailing outflows uplifted by AGN jet ejecta. The infalling NALs may therefore provide direct evidence for cold gas precipitation and accretion in AGN feedback processes, and provide direct evidence of inflowing gas along the directions close to quasar jets and at parsec scale. Regardless of whether these infalling NALs are from the dusty tori or the interaction of AGN jets with the ISM, the infalling NALs cannot provide sufficient fuel to power the quasars.