Luminosity Mass Research Articles

The evolution of [O iii]+H β equivalent width from z ≃ 3 − 8: implications for the production and escape of ionizing photons during reionization

Abstract Accurately quantifying the ionizing photon production efficiency (ξion) of z ≳ 6 star-forming galaxies (SFGs) is necessary to fully understand their contribution to reionization. In this study, we investigate the ionizing properties of N = 279 SFGs selected at z ≃ 6.9 − 7.6 from two of the largest JWST Cycle-1 imaging programmes; PRIMER and JADES. We use bagpipes to consistently infer the equivalent widths (Wλ) of their [O iii]+H β emission lines and their physical properties. To supplement this sample, we measure Wλ([O iii]+H β) photometrically for N = 253zspec = 3.2 − 3.6 SFGs selected from the VANDELS spectroscopic survey. Comparing these samples, we find a strong apparent redshift evolution in their median Wλ([O iii]+H β), increasing from Wλ([O iii]+H β)=380 ± 30 Å in VANDELS to Wλ([O iii]+H β)=540 ± 25 Å in PRIMER+JADES. Concentrating on the JWST sample (z ≳ 7), we find that Wλ([O iii]+H β) correlates with stellar mass and UV luminosity, with high-mass, MUV-faint galaxies producing systematically weaker emission lines. Moreover, we discover a departure from the standard log-normal shape of the Wλ([O iii]+H β) distribution, with a more pronounced tail towards lower Wλ([O iii]+H β), consistent with increasingly bursty star formation. Using Wλ([O iii]+H β) as a proxy for ξion, and UV spectral slope as a proxy for Lyman-continuum escape ($f_\mathrm{esc}^\mathrm{LyC}$), we uncover a minority of galaxies with high ξion and $f_\mathrm{esc}^\mathrm{LyC}$ (e.g., log(ξion/erg−1Hz) ≃ 25.6 and $f_\mathrm{esc}^\mathrm{LyC}$≃ 0.15). However, we find the ionizing photon budget at z ≳ 7 is dominated by galaxies with more moderate output, close to the median values of log(ξion/erg−1Hz) ≃ 25.3 and $f_\mathrm{esc}^\mathrm{LyC}$≃ 0.05. Our results are consistent with estimates for the number of ionizing photons required to power reionization at z ≳ 7, with no evidence for over or under-production.

KiDS-1000: Weak lensing and intrinsic alignment around luminous red galaxies

We study the properties of luminous red galaxies (LRGs) selected from the fourth data release of the Kilo Degree Survey (KiDS-1000) via galaxy-galaxy lensing of the background galaxies from KiDS-1000. We used a halo model formalism to interpret our measurements and obtain estimates of the halo masses as well as the satellite fractions of the LRGs, resulting in halo masses of $2.7 h^ M ⊙ <M_ h h^ M ⊙ $. We studied the strength of intrinsic alignments (IA) using the position-shape correlations as a function of LRG luminosity, where we used a double power law to describe the relation between luminosity and halo mass to allow for a comparison with previous works. Here, we directly linked the observed IA of the (central) galaxy to the mass of the hosting halo, which is expected to be a fundamental quantity in establishing the alignment. We find that the dependence of the IA amplitude on halo mass is described well by a single power law, with an amplitude of A = 5.74 and slope of β_M = 0.44 in the range of $1.9 h^ M ⊙ <M_ h h^ M ⊙ $. We also find that both red and blue galaxies from the source sample associated with the LRGs are randomly oriented, with respect to the LRGs, although our detection significance is limited by the uncertainty in our photometric redshifts.

The evolution of extragalactic peaked-spectrum sources down to 54 megahertz

Peaked-spectrum sources, known for their distinct peaked radio spectra, are a type of radio-loud active galactic nuclei. One subtype, megahertz-peaked-spectrum (MPS) sources, which exhibit a spectral peak at a frequency of a hundred megahertz, have emerged as a potential tool for identifying high-redshift candidates. However, the potential evolutionary link between the fraction of these sources and their redshifts remains unclear and requires further investigation. The recent, high-sensitivity Low Frequency Array (LOFAR) surveys enable statistical studies of these objects down to ultra-low frequencies (< 150 MHz). In this study we first used the multi-radio data to investigate the evolution of spectral index with redshift for 1,187 quasars from the 16th SDSS quasar catalog. For each quasar, we analyzed available data from the LOFAR Low Band Antenna at 54 MHz, the High Band Antenna at 144 MHz, and the Very Large Array Faint Images of the Radio Sky at Twenty centimeters at 1.4 GHz. We measured the spectral index (α^ and α^ ) and find no significant change in their median values with redshift. Extended sources have steeper spectral indices than compact sources, which is consistent with previous findings. Based on the spectral index information, we identified MPS sources using the criteria rm α^ >= 0.1 and rm α^ < 0, and analyzed their properties. We find that the fraction of MPS sources is constant with the redshift ($0.1-4.8$), bolometric luminosity (rm 10^ erg/s), and supermassive black hole mass (rm 10^ M_ ⊙ ), which suggests that MPS sources have relatively stable physical conditions or formation mechanisms across various evolutionary stages and environments.

The Arizona Molecular ISM Survey with the SMT: Variations in the CO(2–1)/CO(1–0) Line Ratio across the Galaxy Population

Abstract The J = 1 → 0 spectral line of carbon monoxide (CO(1–0)) is the canonical tracer of molecular gas. However, CO(2–1) is frequently used in its place, following the assumption that the higher-energy line can be used to infer the CO(1–0) luminosity and molecular gas mass. The use of CO(2–1) depends on a knowledge of the ratio between CO(2–1) and CO(1–0) luminosities, r 21. Here, we present galaxy-integrated r 21 measurements for 122 galaxies spanning stellar masses from 109 to 1011.5 M ⊙ and star formation rates (SFRs) from 0.08 to 35 M ⊙ yr−1. We find strong trends between r 21 and SFR, SFR surface density, star formation efficiency, and distance from the star formation main sequence (SFMS). We show that the assumption of a constant r 21 can introduce biases into the molecular gas trends in galaxy population studies and demonstrate how this affects the recovery of important galaxy scaling relations, including the Kennicutt–Schmidt law and the relation between SFMS offset and star formation efficiency. We provide a prescription that accounts for variations in r 21 as a function of SFR and can be used to convert between CO(2–1) and CO(1–0) when only one line is available. Our prescription matches variations in r 21 for both AMISS and literature samples and can be used to derive more accurate gas masses from CO(2–1) observations.

COOL-LAMPS. VII. Quantifying Strong-lens Scaling Relations with 177 Cluster-scale Strong Gravitational Lenses in DECaLS

Abstract We estimate the Einstein-radius-enclosed total mass for 177 cluster-scale strong gravitational lenses identified by the ChicagO Optically selected Lenses Located At the Margins of Public Surveys (COOL-LAMPS) collaboration with lens redshifts ranging from 0.2 ⪅ z ⪅ 1.0 using the brightest-cluster-galaxy (BCG) redshift and an observable proxy for the Einstein radius. We constrain the Einstein-radius-enclosed luminosity and stellar mass by fitting parametric spectral energy distributions to aperture photometry from the Dark Energy Camera Legacy Survey (DECaLS) in the g-, r-, and z-band Dark Energy Camera filters. We find that the BCG redshift, enclosed total mass, and enclosed luminosity are strongly correlated and well described by a planar relationship in 3D space. We find that the enclosed total mass and stellar mass are correlated with a logarithmic slope of 0.50 0 − 0.031 + 0.029 , and the enclosed total mass and stellar-to-total mass fraction are correlated with a logarithmic slope of − 0.49 5 − 0.033 + 0.032 . In tandem with the small radii within which these slopes are constrained, this may suggest invariance in baryon conversion efficiency and feedback strength as a function of cluster-centric radii in galaxy clusters. Additionally, the correlations described here should have utility in ranking strong-lensing candidates in upcoming imaging surveys—such as Rubin/Legacy Survey of Space and Time—in which an algorithmic treatment of strong lenses will be needed due to the sheer volume of data these surveys will produce.

Long-term Monte Carlo-based neutrino-radiation hydrodynamics simulations for a black hole-torus system

We present our new general relativistic Monte Carlo (MC)-based neutrino radiation hydrodynamics code designed to solve axisymmetric systems with several improvements. The main improvements are as follows: (i) the development of an extended version of the implicit MC method for multispecies radiation fields; (ii) modeling of neutrino pair process rates based on a new numerically efficient and asymptotically correct fitting function for the kernel function; (iii) the implementation of new numerical limiters on the radiation-matter interaction to ensure a stable and physically correct evolution of the system. We apply our code to a black hole (BH)-torus system with a BH mass of 3M⊙, BH dimensionless spin of 0.8, and a torus mass of 0.1M⊙, which mimics a postmerger remnant of a binary neutron star merger in the case that the massive neutron star collapses to a BH within a short timescale (∼10 ms). We follow the evolution of the BH-torus system up to more than 1 s with our MC-based radiation viscous-hydrodynamics code that dynamically takes into account nonthermal pair annihilation. We find that the system evolution and the various key quantities, such as neutrino luminosity, ejecta mass, torus Ye, and pair annihilation luminosity, are broadly in agreement with the results of the previous studies. We also find that the νeν¯e pair annihilation can launch a relativistic outflow for a timescale of ∼0.1 s, and it can be energetic enough to explain some of short-hard gamma-ray bursts and the precursors. Finally, we calculate the indicators of the fast flavor instability directly from the obtained neutrino distribution functions, which indicate that the instability can occur particularly near the equatorial region of the torus. Published by the American Physical Society 2025

A jet-induced shock in a young, powerful radio galaxy at z = 3.00

Abstract The bright radio source, GLEAM J091734 $-$ 001243 (hereafter GLEAM J0917 $-$ 0012), was previously selected as a candidate ultra-high redshift ( $z \gt 5$ ) radio galaxy due to its compact radio size and faint magnitude ( $K(\mathrm{AB})=22.7$ ). Its redshift was not conclusively determined from follow-up millimetre and near-infrared spectroscopy. Here we present new HST WFC3 G141 grism observations which reveal several emission lines including [NeIII] $\lambda$ 3867, [NeV] $\lambda$ 3426 and an extended ( $\approx 4.8\,$ kpc), [OII] $\lambda$ 3727 line which confirm a redshift of $3.004\pm0.001$ . The extended component of the [OII] $\lambda$ 3727 line is co-spatial with one of two components seen at 2.276 GHz in high resolution ( $60\times 20\,$ mas) Long Baseline Array data, reminiscent of the alignments seen in local compact radio galaxies. The BEAGLE stellar mass ( $\approx 2\times 10^{11}\,\textit{M}_\odot$ ) and radio luminosity ( $L_{\mathrm{500MHz}}\approx 10^{28}\,$ W Hz $^{-1}$ ) put GLEAM J0917 $-$ 0012 within the distribution of the brightest high-redshift radio galaxies at similar redshifts. However, it is more compact than all of them. Modelling of the radio jet demonstrates that this is a young, $\approx 50\,$ kyr old, but powerful, $\approx 10^{39}\,$ W, compact steep spectrum radio source. The weak constraint on the active galactic nucleus bolometric luminosity from the [NeV] $\lambda$ 3426 line combined with the modelled jet power tentatively implies a large black hole mass, $\ge 10^9\,\textit{M}_\odot$ , and a low, advection-dominated accretion rate, i.e. an Eddington ratio $\le 0.03$ . The [NeV] $\lambda$ 3426/[NeIII] $\lambda$ 3867 vs [OII] $\lambda$ 3727/[NeIII] $\lambda$ 3867 line ratios are most easily explained by radiative shock models with precursor photoionisation. Hence, we infer that the line emission is directly caused by the shocks from the jet and that this radio source is one of the youngest and most powerful known at cosmic noon. We speculate that the star-formation in GLEAM J0917 $-$ 0012 could be on its way to becoming quenched by the jet.

BSN: The First Photometric Analysis of Contact Binary Systems V1961 Cyg and V0890 Lyr

We presented the first photometric analysis of the V1961 Cyg and V0890 Lyr binary systems. We observed and analyzed these systems at an observatory in France as part of the Binary Systems of South and North (BSN) Project. We extracted and collected the times of minima from the observations and literature and presented a new ephemeris for each system. Due to the few observations about these systems over the years, both O–C diagrams were fitted linearly. The PHysics Of Eclipsing BinariEs (PHOEBE) Python code and the Markov Chain Monte Carlo (MCMC) method were used for light curve solutions. The light curve solution required a cold starspot on the hotter component in the V1961 Cyg binary system. We compared and have close agreements between our mass ratios’ results from the light curve analysis processes and a new method based on the light curve derivative. We estimated the absolute parameters using an empirical relationship between the semimajor axis and orbital period for contact binary systems. The results show V1961 Cyg and V0890 Lyr are W-type contact binary systems. We displayed stars and systems’ positions in the M–L, M–R, and logMtot−logJ0 diagrams. We also presented a new relationship between mass ratio and luminosity ratio.

A Parameter Study of 1D Atmospheric Models of Pulsating AGB Stars

Using the atmospheric pulsation code written by George Bowen, we have performed a parameter study examining the effects of modifying various parameters of models of oxygen-rich AGB atmospheres pulsating in the fundamental and first-overtone modes. For each pulsation mode, we have examined the effects of adjusting the dust condensation temperature, dust condensation temperature range, pulsation amplitude, dust opacity, and metallicity. Our model grids are generated with the constraint that their luminosities are chosen to span the range of observed mass loss rates at a chosen mass. The dust condensation temperature, pulsation amplitude, and dust opacity have strong effects on the ultimate location and shape of the final model grids in the mass luminosity plane. The mass loss rate evolution of the fundamental and first-overtone mode models show a significant difference in behavior. While the fundamental mode models exhibit the typically assumed power–law relation with mass and luminosity, the first-overtone mode models show significant non-power law behavior at observed mass loss rates. Effectively, models in the first-overtone mode require somewhat higher luminosities to reach the same mass loss rates seen in fundamental mode models of the same mass, consistent with observed AGB stars.

Photometric and Spectroscopic Analysis of Eight Totally Eclipsing Contact Binaries with Small Mass Ratios

This paper selected eight totally eclipsing contact binaries for photometric and spectroscopic studies. Spectral data were analyzed by University of Lyon Spectroscopic analysis Software, and photometric data were analyzed using PHOEBE through Markov Chain Monte Carlo (MCMC) sampling. We used two methods to calculate the initial values for running MCMC: one method is a new approach proposed by ourselves to model light curves without spots, while the other method is the genetic algorithm, which can determine physical parameters with spots. The results imply that these eight targets are all contact binary stars with a small mass ratio below 0.25. There are four systems exhibiting the O’Connell effect. By adding a dark spot on the primary component, the ideal fitting can be obtained. Meanwhile, it was found that two systems are shallow contact binaries, while the remaining six are moderate contact binaries. An O − C analysis of the eight eclipsing binary stars revealed that seven of them exhibit long-term changes. Four of them display a long-term decreasing trend in orbital period, while the other three show a long-term increasing trend, and two targets exhibit periodic variations. A decrease in period may be caused by the transfer of matter from the more massive component to the less massive component, while an increase in period may be caused by transfer in the opposite way. The absolute physical parameters, orbital angular momentum, initial masses, and ages of these eight systems were calculated. Additionally, their mass–luminosity and mass–radius distributions were analyzed.

High-redshift, Small-scale Tests of Ultralight Axion Dark Matter Using Hubble and Webb Galaxy UV Luminosities

We calculate the abundance of UV-bright galaxies in the presence of ultralight axion (ULA) dark matter (DM), finding that axions suppress their formation with a non-trivial dependence on redshift and luminosity. We set limits on axion DM using UV luminosity function (UVLF) data, excluding a single axion as all the DM for m ax < 10−21.6 eV and limiting axions with −26≤log(max/eV)≤−23 to be less than 22% of the DM (both at 95% credibility). These limits use UVLF measurements from 24,000 sources from the Hubble Space Telescope (HST) at redshifts 4 ≤ z ≤ 10. We marginalize over a parametric model connecting halo mass and UV luminosity. Our results bridge a window in axion mass and fraction previously unconstrained by cosmological data, between large-scale cosmic microwave background and galaxy clustering and the small-scale Lyα forest. These high-z measurements provide a powerful consistency check of low-z tests of axion DM, including the recent hint for a sub-dominant ULA DM fraction in Lyα forest data. We also consider a sample of 25 spectroscopically confirmed high-z galaxies from the James Webb Space Telescope (JWST), finding these data to be consistent with HST. Combining HST and JWST UVLF data does not improve our constraints beyond HST alone, but future JWST measurements have the potential to improve these results. We also find an excess of low-mass halos (<109 M ⊙) at z < 3, which could be probed by subgalactic structure probes (e.g., stellar streams, satellite galaxies, and strong lensing).

KASHz+SUPER: Evidence of cold molecular gas depletion in AGN hosts at cosmic noon

The energy released by active galactic nuclei (AGN) has the potential to heat or remove the gas of the ISM, thus likely impacting the cold molecular gas reservoir of host galaxies at first, with star formation following as a consequence on longer timescales. Previous works on high-z galaxies, which compared the gas content of those without identified AGN, have yielded conflicting results, possibly due to selection biases and other systematics. To provide a reliable benchmark for galaxy evolution models at cosmic noon (z = 1 − 3), two surveys were conceived: SUPER and KASHz, both targeting unbiased X-ray-selected AGN at z &gt; 1 that span a wide bolometric luminosity range. In this paper we assess the effects of AGN feedback on the molecular gas content of host galaxies in a statistically robust, uniformly selected, coherently analyzed sample of AGN at z = 1 − 2.6, drawn from the KASHz and SUPER surveys. By using targeted and archival ALMA data in combination with dedicated SED modeling, we retrieve CO and far-infrared (FIR) luminosity as well as M* of SUPER and KASHz host galaxies. We selected non-active galaxies from PHIBBS, ASPECS, and multiple ALMA/NOEMA surveys of submillimeter galaxies in the COSMOS, UDS, and ECDF fields. By matching the samples in redshift, stellar mass, and FIR luminosity, we compared the properties of AGN and non-active galaxies within a Bayesian framework. We find that AGN hosts at given FIR luminosity are on average CO depleted compared to non-active galaxies, thus confirming what was previously found in the SUPER survey. Moreover, the molecular gas fraction distributions of AGN and non-active galaxies are statistically different, with the distribution of AGN being skewed to lower values. Our results indicate that AGN can indeed reduce the total cold molecular gas reservoir of their host galaxies. Lastly, by comparing our results with predictions from three cosmological simulations (TNG, Eagle, and Simba) filtered to match the properties of observed AGN, AGN hosts, and non-active galaxies, we confirm already known discrepancies and highlight new discrepancies between observations and simulations.

Modeling ALMA Observations of the Warped Molecular Gas Disk in the Red Nugget Relic Galaxy NGC 384

We present 0.″22 resolution CO(2–1) observations of the circumnuclear gas disk in the local compact galaxy NGC 384 with the Atacama Large Millimeter/submillimeter Array (ALMA). While the majority of the disk displays regular rotation with projected velocities rising to 370 km s−1, the inner ∼0.″5 exhibits a kinematic twist. We develop warped disk gas-dynamical models to account for this twist, fit those models to the ALMA data cube, and find a stellar mass-to-light ratio in the H band of M/L H = 1.34 ± 0.01 [1σ statistical] ±0.02 [systematic] M ⊙/L ⊙ and a supermassive black hole (BH) mass (M BH) of M BH =(7.26−0.48+0.43[1σstatistical]−1.00+0.55[systematic])×108M⊙ . In contrast to most previous dynamical M BH measurements in local compact galaxies, which typically found over-massive BHs compared to the local BH mass−bulge luminosity and BH mass−bulge mass relations, NGC 384 lies within the scatter of those scaling relations. NGC 384 and other local compact galaxies are likely relics of z ∼ 2 red nuggets, and over-massive BHs in these relics indicate BH growth may conclude before the host galaxy stars have finished assembly. Our NGC 384 results may challenge this evolutionary picture, suggesting there may be increased scatter in the scaling relations than previously thought. However, this scatter could be inflated by systematic differences between stellar- and gas-dynamical measurement methods, motivating direct comparisons between the methods for NGC 384 and the other compact galaxies in the sample.

Witnessing an extreme, highly efficient galaxy formation mode with resolved Lyman-α and Lyman-continuum emission

J1316+2614 at z = 3.613 is the UV-brightest (MUV = −24.7) and strongest Lyman continuum-emitting (fescLyC ≈ 90%) star-forming galaxy known; it also shows signatures of inflowing gas from its blue-dominated Lyα profile. We present high-resolution imaging with the Hubble Space Telescope (HST) and the Very Large Telescope (VLT) of the LyC, Lyα, rest-UV, and optical emission of J1316+2614. Detailed analysis of the LyC and UV light distributions reveals compact yet resolved profiles, with LyC and UV morphologies showing identical half-light radii of reff ≃ 220 pc. The continuum-subtracted Lyα emission, obtained with the HST ramp-filter FR551N, reveals an extended filamentary structure of ≃6.0 kpc oriented south to north with only residual flux within the stellar core, suggesting a Lyα ‘hole’. Our spectral energy distribution analysis shows that J1316+2614 is characterised by a young (5.7 ± 1.0 Myr), nearly un-obscured stellar population with a high star-formation rate (SFR = 898 ± 181 M⊙ yr−1) and a stellar mass of M⋆young = (4.8 ± 0.3) × 109 M⊙. Additionally, the spectral energy distribution analysis supports the absence of an underlying old stellar population (M⋆old ≤ 2.8 × 109 M⊙, 3σ). J1316+2614 presents remarkably high SFR and stellar mass surface densities of log(Σ SFR[M⊙ yr−1 kpc−2]) = 3.47 ± 0.11 and log(ΣM⋆[M⊙pc−2]) = 4.20 ± 0.06, respectively, which are among the highest observed in star-forming galaxies and are more typically observed in local young massive star clusters and globular clusters. Our findings indicate that J1316+2614 is a powerful, young, and compact starburst that is leaking a significant amount of LyC photons due to a lack of gas and dust within the starburst. We explored the conditions for gas expulsion using a simple energetic balance and find that, given the strong binding force in J1316+2614, a high star-formation efficiency (ϵSF ≥ 0.7) is necessary to explain the removal of gas and its exposed nature. Our results thus suggest a close link between high ϵSF and high fescLyC. This high efficiency can also naturally explain the remarkably high SFR, UV luminosity, and efficient mass growth of J1316+2614, which acquired at least 62% of its mass in the last 6 Myr. J1316+2614 may exemplify an intense, feedback-free starburst with a high ϵSF, similar to those proposed for UV-bright galaxies at high redshifts.

X-ray reverberation modelling of the continuum, optical/UV time-lags in quasars

Extensive, multi-wavelength monitoring campaigns of nearby and higher redshift active galactic nuclei (AGN) have shown that the UV/optical variations are well correlated with time delays which increase with increasing wavelength. Such behaviour is expected in the context of the X-ray thermal reverberation of the accretion disc in AGN. Our main objective is to use time-lag measurements of luminous AGN and fit them with sophisticated X-ray reverberation time-lags models. In this way we can investigate whether X-ray reverberation can indeed explain the observed continuum time lags, and whether time-lag measurements can be used to measure physical parameters such as the X-ray corona height and the spin of the black hole (BH) in these systems. We use archival time-lag measurements for quasars from different surveys, and we compute their rest frame, mean time-lags spectrum. We fit the data with analytical X-ray reverberation models, using $ statistics, and fitting for both maximal and non spinning BHs, for various colour correction values and X-ray corona heights. We found that X-ray reverberation can explain very well the observed time lags, assuming the measured BH mass, accretion rate and X-ray luminosity of the quasars in the sample. The model agrees well with the data both for non-rotating and maximally rotating BHs, as long as the corona height is larger than $ 40$ gravitational radii. This is in agreement with previous results which showed that X-ray reverberation can also explain the disc radius in micro-lensed quasars, for the same corona heights. The corona height we measure depends on the model assumption of a perfectly flat disc. More realistic disc models may result in lower heights for the X-ray corona.

z ∼ 2 dual AGN host galaxies are disky: stellar kinematics in the ASTRID Simulation

We study dual AGN host galaxy morphologies at z=2 using the ASTRID simulation, selecting black hole (BH) pairs with small separation (), high mass ( MBH,12&gt;107M⊙), and luminosity (). We kinematically decompose (using MORDOR) ∼1000 dual AGN hosts into standard components - a ‘disk’ (thin and thick disk, pseudo-bulge) and ‘bulge’ (bulge and halo) and define disk-dominated galaxies by the disk-to-total D/T≥0.5. In ASTRID, 60.9±2.1% of dual AGN hosts (independent of separation) are disk-dominated, with the D/T distribution peaking at ∼0.7. In dual-AGN hosts, the D/T increases from $17% $ at to $ 64% $ for , and the pseudo-bulge is the dominant component of the disk fraction at the high mass end. Moreover, dual AGN hosts exhibit a higher fraction of disk/large pseudo-bulge than single-AGN hosts. The Disk-to-Total ratio is approximately constant with BH mass or AGN luminosity. We also create mock images of dual AGN host galaxies, employing morphological fitting software Statmorph to calculate morphological parameters and compare them with our kinematic decomposition results. Around 83.3±2.4% of galaxies display disk-like profiles, of which ∼60.7±2.2% are kinematically confirmed as disks. Se'rsic indices and half-mass radii of dual AGN host galaxies align with observational measurements from HST at z∼2. Around 34% are identified as mergers from the Gini−M20 relation. We find two dual AGN hosted by galaxies that exhibit disk-like se'rsic index n12&lt;1 and (D/T)12&gt;0.5, which are in remarkable agreement with properties of recently discovered dual quasars in disk galaxies at z∼2.

Prior-informed Active Galactic Nucleus Host Spectral Decomposition Using PyQSOFit

We introduce an improved method for decomposing the emission of active galactic nuclei (AGN) and their host galaxies using templates from principal component analysis (PCA). This approach integrates prior information from PCA with a penalized pixel fitting mechanism that improves the precision and effectiveness of the decomposition process. Specifically, we have reduced the degeneracy and overfitting in AGN host decomposition, particularly for those with low signal-to-noise ratios (SNRs), where traditional methods tend to fail. By applying our method to 76,565 Sloan Digital Sky Survey Data Release 16 quasars with z < 0.8, we achieve a success rate of ≈94%, thus establishing the largest host-decomposed spectral catalog of quasars to date. Our fitting results consider the impact of the host galaxy on the overestimation of the AGN luminosity and black hole mass (M BH). Furthermore, we obtained stellar velocity dispersion (σ ⋆) measurements for 4137 quasars. The slope of the M BH−σ ⋆ relation in this subsample is generally consistent with previous quasar studies beyond the local Universe. Our method provides a robust and efficient approach to disentangle the AGN and host galaxy components across a wide range of SNRs and redshifts.

The factors that influence protostellar multiplicity

Context. Protostellar multiplicity is common at all stages and mass ranges. However, the factors that determine the multiplicity of protostellar systems have not been systematically characterized through their molecular gas. Aims. We characterize the physical properties of the Perseus molecular cloud at ≥5000 AU scales by mapping the diagnostic molecular lines. Methods. We used Nobeyama 45m Radio Observatory (NRO) on-the-fly maps of HCN, HNC, HCO+, and N2H+ (J=1–0) toward five subregions in Perseus, complemented with single-pointing Atacama Pathfinder Experiment (APEX) observations of HNC (J = 4–3), to derive the physical parameters of the dense gas. The spatial resolutions of both observations were ~18″, which is equivalent to ~5000 AU scales at the distance of Perseus. The kinetic gas temperature was derived from the I(HCN)/I(HNC) J ratio, and the H2 density was obtained from the HNC J=4–3/J=1–0 ratio. These parameters were used to obtain the N2H+ (cold) and HCO+ (warm) gas masses. The inferred and derived parameters were then compared to source the parameters, including protostellar multiplicity, bolometric luminosity, and dust envelope mass. Results. The inferred mean kinetic gas temperature (I(HCN)/I(HNC) J=1–0 ratio; ranging between 15 and 26 K), and H2 volumetric density (HNC J=4–3/J=1–0; 105−106 cm−3) are not correlated with multiplicity in Perseus. The derived gas and dust masses, 1.3 to 16 × 10−9 M⊙ for the cold-gas mass (N2H+), 0.1 to 25 M⊙ for the envelope dust masses (850 μm), and 0.8 to 10 × 10−10 M⊙ for the warm-gas mass (HCO+), are correlated to multiplicity and to the number of protostellar components. The warm-gas masses are lower by a factor of 16 than the cold-gas masses. Conclusions. The gas and dust mass is correlated to multiplicity at ~5000 AU scales in Perseus. Higher-order multiples tend to have higher gas and dust masses in general, while close binaries (separations ≤7″) and single protostars have similar gas and dust mass distributions. On the other hand, the H2 density and kinetic gas temperature are not correlated with multiplicity.

The fundamental plane of black hole activity for low-luminosity radio active galactic nuclei across 0 &lt; z &lt; 4

Context. The fundamental plane of black hole activity describes the correlation between radio luminosity (LR), X-ray luminosity (LX), and black hole mass (MBH). It reflects a connection between the accretion disc and the jet. However, the dependence of the fundamental plane on various physical properties of active galactic nuclei (AGNs) and host galaxies remains unclear, especially for low-luminosity AGNs, which is important for understanding the accretion physics in AGNs. Aims. Here, we explore the dependence of the fundamental plane on the radio loudness, Eddington-ratio (λEdd), redshift, and galaxy star formation properties (star-forming galaxies and quiescent galaxies) across 0.1 &lt; z ≤ 4 for radio AGNs. Based on current deep and large surveys, our studies can extend to lower luminosities and higher redshifts. Methods. From the deep and large multi-wavelength surveys in the GOODS-N, GOODS-S, and COSMOS/UltraVISTA fields, we constructed a large and homogeneous radio AGN sample consisting of 208 objects with available estimates for LR and LX. Then we divided the radio AGN sample into 141 radio-quiet AGNs and 67 radio-loud AGNs according to the radio loudness defined by the ratio of LR to LX, and explored the dependence of the fundamental plane on different physical properties of the two populations, separately. Results. The ratio of LR to LX shows a bimodal distribution that is well described by two single Gaussian models. The cross point between these two Gaussian components corresponds to a radio-loudness threshold of log(LR/LX) = − 2.73. The radio-quiet AGNs have a significantly larger Eddington ratio than the radio-loud AGNs. Our radio-quiet and radio-loud AGNs show a significantly different fundamental plane, which indicates a significant dependence of the fundamental plane on the radio loudness. For both radio-quiet and radio-loud AGNs, the fundamental plane shows a significant dependence on λEdd, but no dependence on redshift. The fundamental plane shows a significant dependence on the galaxy star formation properties for radio-quiet AGNs, while for radio-loud AGNs this dependence disappears. Conclusions. The fundamental plane sheds important light on the accretion physics and X-ray emission origins of central engines. X-ray emission of radio-quiet AGNs at 0.01 &lt; λEdd &lt; 0.1 are produced by a combination of advection-dominated accretion flow (ADAF) and synchrotron radiation from the jet, while at 0.1 &lt; λEdd &lt; 1 they mainly follow the synchrotron jet model. The origins of X-ray emission of radio-loud AGNs are consistent with a combination of ADAF and the synchrotron jet model at λEdd &lt; 0.01, agree with the synchrotron jet model at 0.01 &lt; λEdd &lt; 0.1, and follow a combination of the standard thin disc and a jet model at λEdd &gt; 0.1.

The properties and kinematics of HCN emission across the closest starburst galaxy NGC 253 observed with ALMA

Context. Investigating molecular gas tracers, such as hydrogen cyanide (HCN), to probe higher densities than CO emission across nearby galaxies remains challenging. This is due to the large observing times required to detect HCN at a high sensitivity and spatial resolution. Although approximate kiloparsec scales of HCN maps are available for tens of galaxies, higher-resolution maps still need to be available. Aims. We aim to study the properties of molecular gas, the contrast in intensity between two tracers that probe different density regimes (the HCN(1–0)/CO(2–1) ratio), and their kinematics across NGC 253, one of the closest starburst galaxies. With its advanced capabilities, the Atacama Large Millimeter/submillimeter Array (ALMA) can map these features at a high resolution across a large field of view and uncover the nature of such dense gas in extragalactic systems. Methods. We present new ALMA Atacama Compact Array and Total Power (ACA+TP) observations of the HCN emission across NGC 253. The observations cover the inner 8.6′ of the galaxy disk at a spatial resolution of 300 pc. Our study examines the distribution and kinematics of the HCN-traced gas and its relationship with the bulk molecular gas traced by CO(2–1). We analyze the integrated intensity and mean velocity of HCN and CO along each line of sight. We also used the SCOUSE software to perform spectral decomposition, which considers each velocity component separately. Results. We find that the denser molecular gas traced by HCN piles up in a ring-like structure at a radius of 2 kpc. The HCN emission is enhanced by two orders of magnitude in the central 2 kpc regions, beyond which its intensity decreases with increasing galactocentric distance. The number of components in the HCN spectra shows a robust environmental dependence, with multiple velocity features across the center and bar. The HCN spectra exhibit multiple velocity features across the center and bar, which shows a robust environmental dependence. We have identified an increase in the HCN/CO ratio in these regions, corresponding to a velocity component likely associated with a molecular outflow. We have also discovered that the ratio between the total infrared luminosity and dense gas mass, which is an indicator of the star formation efficiency of dense gas, is anticorrelated with the molecular gas surface density up to approximately 200 M⊙ pc−2. However, beyond this point, the ratio starts to increase. Conclusions. We argue that using information about spectroscopic features of molecular emission is an important aspect of understanding molecular properties in galaxies.