Search Results (123)

Pulque is a traditional Mexican beverage produced by the spontaneous fermentation of “aguamiel”, the sap of several Agave species. Fermentation is driven by adding a previously fermented inoculum, locally known as “semilla”, whose microbial community contributes to the sensory and physicochemical properties of the beverage. The objective of this study was to provide a preliminary characterization of the microbial taxonomic composition and functional potential of pulque inoculant prepared from Agave mapisaga and Agave salmiana using shotgun metagenomic sequencing. Six inoculum samples were sequenced on the DNBSEQ using 150 bp paired-end reads. Metagenomic DNA was extracted using a CTAB-based protocol and analyzed in the Galaxy platform. The workflow included quality filtering, host-sequence removal, taxonomic classification with Kraken2, assembly with MEGAHIT, and functional annotation with eggNOG Mapper. Bacterial communities in inoculum from A. mapisaga and A. salmiana sap were dominated by Acetobacter (68.1% and 58.3%) and Leuconostoc (19.5% and 21.9%). Komagataeibacter was more abundant in A. mapisaga inoculum (3.8%), whereas Zymomonas was more abundant in A. salmiana inoculum (11.7%). The greatest species-level difference was observed for Zymomonas mobilis, whose mean relative abundance was 6.4-fold higher in A. salmiana. Fungal communities were dominated by Saccharomyces (91.4% and 72.7%) and Kluyveromyces (6.6% and 25.5%) in A. mapisaga and A. salmiana, respectively. Across all replicates, the most abundant species were Acetobacter sp. AC2005 (23.9%), Saccharomyces paradoxus (17.0%), and Zymomonas mobilis (12.9%), together accounting for approximately 54% of the total relative abundance. Kluyveromyces marxianus was 3.9-fold more abundant in A. salmiana inoculum, whereas Saccharomyces paradoxus was 1.26-fold more abundant in A. mapisaga inoculum. Alpha-diversity analysis indicated higher bacterial diversity in A. mapisaga inoculum, with a Shannon index of 2.74 and 35 exclusive species, whereas A. salmiana inoculum showed greater fungal diversity, with a Shannon index of 0.68. These differences were not statistically significant (p > 0.05). However, beta-diversity analysis suggested substantial separation between the microbial communities associated with the two Agave species (R² ≈ 0.92). Functional annotation identified genes potentially associated with carbohydrate metabolism, sucrose degradation, and secondary metabolite biosynthesis. These findings suggest that the agave species used as the sap source may influence the taxonomic composition and functional potential of microbial communities involved in pulque fermentation. Full article

The fifth edition of the Roma-BZCAT catalog (5BZCAT) contains 227 blazars of the uncertain type (BZU), whose available data do not support an unambiguous assignment to the BL Lacertae object (BZB), flat-spectrum radio quasar (BZQ), or host-galaxy-dominated blazar-like source (BZG) categories. We construct a machine-readable value-added catalog for these sources using 1151 BZB, 1909 BZQ, and 274 BZG catalog entries as the supervised reference sample. The compact input set contains redshift, optical magnitude, radio, X-ray, and gamma-ray measurements; missingness indicators; and spectral slopes connecting the radio, optical, and X-ray bands. Redshift and its availability are explicitly treated as optical-spectroscopy-related label proxies. Cross-validation shows that the Light Gradient Boosting Machine (LightGBM) provides the most reliable probability scores among the tested models, although the stacking ensemble gives a slightly higher balanced accuracy. The final catalog reports LightGBM probabilities and contains 61 BZB-like, 120 BZQ-like, and 46 BZG-like sources; 17 are flagged for low probability separation. These probabilities quantify similarity to existing 5BZCAT labels conditional on catalog measurements, rather than an independent physical taxonomy. Full article

Narrow-line Seyfert 1 (NLS1) galaxies host active galactic nuclei (AGN) with narrow optical emission lines of the broad-line region. This is often explained with a relatively lower mass of the central supermassive black hole and super-Eddington accretion. We compared the radio properties of large samples of NLS1 and broad-line Seyfert 1 (BLS1) galaxies compiled from the Sloan Digital Sky Survey. We cross-matched the NLS1 and BLS1 samples with the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) sky survey at $1.4$ GHz and the first and second epoch data of the Very Large Array Sky Survey (VLASS) at 3 GHz. We calculated the radio spectral indices, the $1.4$-GHz radio power, and the radio loudness. We found lower $1.4$-GHz radio detection rates for the NLS1 galaxies. The median radio loudness values, the fraction of radio-loud AGN, and the median $1.4$-GHz radio power are also lower for the NLS1 sample. The median spectral indices imply a slightly steeper radio spectrum for the NLS1 sample than for the BLS1 sample. Comparison of the star formation rates estimated from the radio data and the infrared measurements of the Wide-field Infrared Survey Explorer satellite indicated that more than half of the FIRST- and VLASS-detected NLS1 and BLS1 galaxies contain radio-emitting AGN. Full article

The well-established anti-correlation between disk winds and relativistic jets in X-ray binaries is often interpreted in a scale-invariant black hole accretion context. If so, active galactic nuclei (AGN) should exhibit a direct mass-scaled analog. We test this prediction across FRII radio quasars, radio-quiet quasars, and jetted and non-jetted Narrow Line Seyfert 1 galaxies (NLS1) in spirals, among others. They exclude simple scale invariance. The highest-velocity winds occur exclusively in radio-quiet quasars, while powerful FRII quasars host systematically weaker winds despite equally large black hole masses. Jetted NLS1s show strong wind suppression consistent with X-ray binary behavior, whereas FRII quasars occupy a distinct regime in which jets and winds coexist. Black hole mass and spin magnitude alone cannot account for this dichotomy. We argue that the angular momentum direction of the disk relative to that of the black hole (aligned versus anti-aligned or co-rotation versus counter-rotation) is the critical parameter: secularly fueled spiral systems and most post-merger systems favor co-rotation, which is associated with compact ISCO radii, high radiative efficiency, strong winds, and jet suppression, while the counter-rotating subset of merger-influenced ellipticals can sustain powerful jets alongside moderate winds. Moreover, while spiral AGN and merger-driven radio-quiet quasars experience similar strong jet/wind anti-correlation, they cannot be treated as strict scaled analogs of X-ray binaries, which undergo rapid state transitions involving magnetic flux redistribution absent in AGN. At least two distinct wind–jet regimes therefore operate across the mass scale. We identify the details of this behavior across AGN subclasses. Full article

The [O ii] $\lambda 3727$ emission line is a widely used star formation rate (SFR) tracer. However, its application to type I quasars is not straightforward, because the line can be affected by dust extinction, metallicity and contamination from the AGN narrow-line region (NLR). We test the reliability of [O ii] SFRs using a sample of 202 SDSS and PG quasars, by comparing [O ii] SFRs and reference far-infrared (FIR) SFRs derived from multiwavelength SED decomposition. We measure [O ii], [O iii], and narrow Balmer emission lines by spectral fitting. Then, we calculate [O ii] SFRs after correcting dust extinction and metallicity. We then compare these SFRs with the FIR SFRs, both with and without subtracting the AGN contribution estimated from [O iii]. After this correction, the median offset between [O ii] and FIR SFRs is $-0.20\pm 0.72$ dex for the full analysis sample and $-0.17\pm 0.69$ dex for sources with S/N $>5$ in both [O ii] and [O iii]. Without subtracting the AGN contribution, the corresponding offsets are $0.00\pm 0.69$ and $0.12\pm 0.66$ dex. We conclude that [O ii] is useful as a statistical SFR tracer for quasar host galaxies, but individual objects still require careful treatment of AGN contamination, extinction, metallicity, aperture effects, and redshift-dependent systematics. Full article

Reliable star formation rates (SFRs) are essential for studying the connection between black hole growth and quasar host galaxies. We study the far-infrared (FIR) SFRs and the host galaxy properties of 202 SDSS and PG quasars at $0.02<z\lesssim 0.8$, spanning $log({\mathrm{SFR}}_{\mathrm{FIR}}/M_{\odot }{\mathrm{yr}}^{-1})\simeq -0.45$–$2.76$, using multiwavelength spectral energy distribution (SED) decomposition. The photometry covers wavelengths from the optical to the FIR and is supplemented by JCMT/SCUBA-2 observations at 450 and 850 $\mathsf{\mu }$m. We model the SEDs with CIGALE and AGNfitter and adopt multiple cold dust templates to quantify systematic uncertainties. The median model-dependent scatter among the five FIR SFR estimates is $0.14$ dex, and AGNfitter gives FIR SFRs lower than the mean CIGALE estimate by a median of $0.09$ dex. For the 58 quasars with SCUBA-2 coverage, including SCUBA-2 data changes the adopted FIR SFR by only ∼0.01 dex on average but can affect individual sources with limited Herschel coverage or radio-loud emission. Within our FIR-constrained sample, many quasar hosts lie on or above the star-forming main sequence, but the redshift-dependent FIR selection of the SDSS subsample limits conclusions about the full quasar-host population. We find no clear correlation between the main-sequence (MS) offset and the direct Eddington ratio, while the offset is positively related to the infrared-based $L_{\mathrm{tor}}/L_{\mathrm{Edd}}$ proxy. The minimum radiation field intensity in the dust model, $U_{\min }$, increases with bolometric luminosity and dust temperature. WISE W2 (4.6 $\mathsf{\mu }$m) and W3 (12 $\mathsf{\mu }$m) combined with Herschel bands can also provide useful empirical indicators of $f_{\mathrm{AGN}}$. Full article

Dwarf galaxies, although intrinsically faint and containing only modest stellar populations, provide an unusually sensitive testing ground for understanding how structure emerges in a cosmological context. Their shallow gravitational potentials make them particularly responsive to environmental influences and internal feedback, allowing researchers to probe physical processes that are harder to isolate in larger systems. Over the past decade, advances in numerical modeling—ranging from finely resolved hydrodynamic calculations to large-volume N-body suites—have offered increasingly detailed views of their kinematic evolution, star formation cycles, and dark matter configurations. Modern simulations now reproduce several of the empirical relationships observed in nearby dwarfs, including trends connecting mass, size, chemical enrichment, and luminosity. However, uncertainties in how feedback is implemented still produce noticeable variation among models. A long-standing tension involves the predicted shape of central dark matter profiles. Many simulations generate steep cusps, even though observations frequently point to shallower cores. Energetic stellar activity has been proposed as a mechanism for reshaping these regions, yet its effectiveness depends sensitively on resolution and feedback prescriptions. Another unresolved issue concerns the unexpectedly small number of known satellites in the Local Group compared with the abundance of low-mass halos in ΛCDM predictions. Recent work indicates that many such halos may host extremely faint systems that elude current surveys. Large simulation programs such as FIRE, APOSTLE, and NIHAO pursue these questions with differing assumptions and numerical strategies. Each captures certain aspects of dwarf galaxy evolution, but none fully replicates the diversity seen observationally. Considering results from multiple frameworks remains essential for constructing a comprehensive picture of how these small galaxies form, evolve, and interact with their environments. Full article

Simulations of intermediate-mass black holes (IMBHs) in dwarf galaxies within 10 Mpc that host bright nuclear star clusters (NSCs), prime candidates for IMBH formation, using the High Angular Resolution Monolithic Optical and Near-infrared Integral (HARMONI) field spectrograph on the Extremely Large Telescope, probe black hole formation in the early universe. Our approach combines observed surface-brightness profiles from the Hubble Space Telescope (HST), synthetic stellar population spectra, and Jeans Anisotropic Modeling (JAM) for stellar dynamics. Mock HARMONI observations were generated with the HSIM simulator and analyzed in a Bayesian framework to infer IMBH masses down to 0.5% of the NSC mass. In this work, we extend these simulations by constructing improved stellar mass models using SimCADO to simulate imaging with the Multi-AO Imaging Camera for Deep Observations (MICADO). The MICADO data are jointly analyzed with HARMONI kinematics via JAM to reassess IMBH masses and uncertainties. This combined framework enables us to examine how variations in the NSC inner surface-brightness slope influence IMBH mass estimates, providing tighter constraints on low-mass black holes and advancing models for IMBH detection in NSCs. Full article

We present a comprehensive study of host galaxies of radio sources within the 1.35$R_{200}$ of the Coma cluster by combining deep $144\mathrm{MHz}$ observations from the LOFAR Two-Metre Sky Survey (LoTSS-DR2) with optical spectroscopy and photometry from DESI and SDSS. We identify 79 spectroscopically confirmed cluster members with reliable radio emission and classify them into compact, extended, and tailed subsamples according to their radio morphologies. By combining their radio and optical properties, we find compact radio sources are predominantly associated with massive, quiescent galaxies driven by $\mathrm{AGN}$ activity, while tailed sources are largely hosted by star-forming galaxies, tracing ongoing ram pressure stripping ($\mathrm{RPS}$). Using phase-space analysis and a projected infall time proxy ($d_R$), we find that extended sources are preferentially located in the cluster outskirts ($d_R>1$), while tailed sources are concentrated in the intermediate infall region ($0.4<d_R<1.0$), highlighting the influence of the dense intracluster medium. Full article

The gravitational wave event GW190521 seems to be the only BH merger event possibly correlated with an electromagnetic counterpart, which appeared about 34 days after the GW event. This work aims to confirm that the electromagnetic bump towards the Active Galactic Nucleus (AGN) J1249+3449 can be explained within the framework of the gravitational microlensing phenomenon. In particular, considering the data of the Zwicky Transient Facility (ZTF), what emerges from a detailed analysis of the observed light curve using three fitting models (Point Source Point Lens, Finite Source Point Lens, Uniform Source Binary Lens) is that the optical bump can be explained as a microlensing event caused by a lens with mass $\sim$0.1 $M_{\odot }$, lying in the host galaxy of the AGN in question. Full article

Supernova (SN) cosmology is based on the assumption that the luminosity of type Ia SNe, after the luminosity standardization process, remains invariant with progenitor age. However, our comprehensive age measurements of SN host galaxies reveal a significant ($5.5\sigma$) correlation between standardized SN luminosity and progenitor age, which is expected to introduce a serious systematic bias with redshift in SN cosmology. After correcting for this age bias with redshift, the SN dataset aligns more closely with the recent DESI BAO result, bringing the updated ’standard candle’ (SNe) into concordance with the ’standard ruler’ (BAO). When the three cosmological probes (SNe, BAO, CMB) are combined, we find a strong (∼9$\sigma$) discordance with the $\mathrm{\Lambda }$CDM model, suggesting a time-varying dark energy equation of state in a currently non-accelerating universe. Full article

IC 10 is a dwarf galaxy in Cassiopeia, located at a distance of 660 kpc, and hosts a young stellar population, a large number of Wolf–Rayet stars, and a large number of massive stars in general. Utilizing a series of 11 Chandra observations (spanning 2003–2021, with a total exposure of 235.1 ks), 375 point sources of X-ray emission were detected. Similar studies have been conducted earlier in the central region of IC 10. Here, we consider all regions covered by Chandra-ACIS. By comparing our catalog of X-ray sources with a published optical catalog, we found that 146 sources have optical counterparts. We also created a list of 60 blue supergiant (SG) candidates with X-ray binary (XRB) companions by using an optical color–magnitude selection criterion to isolate the blue SGs. Blue SG-XRBs form a major class of progenitors of double-degenerate binaries. Hence, their numbers are an important factor in modeling the rate of gravitational-wave sources. Identifying the nature of individual sources is necessary as it paves the way toward a comprehensive census of XRBs in IC 10, thus enabling meaningful comparisons with other Local Group galaxies exhibiting starbursts, such as the Magellanic Clouds. Full article

Measuring supermassive black hole (SMBH) masses is fundamental to understanding active galactic nuclei (AGN) and their coevolution with host galaxies. Among existing techniques, H₂O megamaser observations with Very Long Baseline Interferometry (VLBI) provide the most direct and geometric determinations of SMBH masses by tracing molecular gas in sub-parsec Keplerian disks. Over the past two decades, the Megamaser Cosmology Project (MCP) has surveyed thousands of nearby AGNs and obtained high-sensitivity VLBI maps of dozens of maser disks that lead to accurate SMBH masses with uncertainties typically below 10%. In this paper, we present a comprehensive review that summarizes the essential elements required to obtain accurate black hole masses with the H₂O megamaser technique—including the physical conditions for maser excitation, observational requirements, disk modeling, and sources of SMBH mass uncertainty—and we discuss the implications of maser-based measurements for exploring SMBH demographics. In particular, we will show that maser-derived black hole masses, largely free from the systematic biases of stellar or gas-dynamical methods, provide critical anchors at the low-mass end of the SMBH population (M_BH∼10⁷M_⊙), and reveal possible deviations from the canonical M_BH–σ_∗ relation. With forthcoming spectroscopic surveys and advances in millimeter/submillimeter VLBI, the maser technique promises to extend precise dynamical mass measurements to both larger local samples and high-redshift galaxies. Full article

Type Ia supernovae are used as fundamental probes of the cosmological parameters, based on a tight empirical relation between their peak luminosity and the width of their light curve. However, it has been recognized that SNe Ia are not “standard” candles, since important variations in their peak luminosities are observed, as a function of the metallicity, age, environment, and morphological type of the supernova hosts. The largest correction in the standardization scheme is related to extinction. While extinction in the Milky Way (MW) Galaxy is usually known and extinction between galaxies can be assumed to be zero, the value of extinction in the SN Ia host galaxy ($A_{host}$) is determined with much more uncertainty. In this paper, we provide an estimate of the $A_{host}$ value based on statistical modeling. To do this, we generate, based on MaNGA data, a set of galaxies in the vicinity of the MW, and distribute the parameters of the galaxies and the positions of SNe Ia in them. As a result, using a simplified model for the distribution of interstellar matter, which is the same for all the sampled galaxies, we can estimate the probability that $A_{host}$ exceeds a certain value. Our estimates show, in particular, that in almost all cases, $A_{host}$ > 0.10 mag V, and in 25% of cases, $A_{host}$ > 0.25 mag V. Full article

STRange and Odd Morphology Extragalactic Radio Sources (STROMERSs) is a new category of radio galaxies that shows extremely peculiar anatomy. A purely manual visual search is carried out for the identification of such interesting sources. We reported a total of 108 STROMERS sources from the LOFAR Two-meter Sky Survey second data release (LoTSS DR2) at 144 MHz. The host galaxies are found ∼94% of the sources. We studied the radio and optical properties of the sources. Redshifts were found in 76% of sources with known host galaxies. The redshifts of STROMERS range from 0.0015 to 1.6599 and peak at 0.15. Among the reported STROMERS sources, there are 17 giant radio galaxies (GRG) with a linear size of greater than 700 kpc. Among them, only five GRGs are new, which is a small fraction of the population of GRGs from LoTSS DR2 data. The source ILTJ164117.44 +380208.4 has the highest linear size, approximately 1.8 Mpc. To study the reasons behind these interesting morphologies, we studied the galaxy cluster environment of each candidate within a 1 Mpc search radius. We found that 53% of STROMERS candidates are associated with cluster environments with known redshifts. The source ILTJ150956.65+332642.9 is associated with a high mass galaxy cluster Abell 2034 with mass a 7.57 $\times {10}^{14}{M}_{\odot }$. We also propose that the merger scenario is one of the reasons for the formation of STROMERS in the paper. Full article