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In this work, we propose that the time variation in mid-infrared (MIR) color is a promising probe to distinguish between MIR outbursts induced by tidal disruption events (TDEs) and changing-look active galactic nuclei (CLAGNs). With an optically selected sample containing TDEs, ambiguous nuclear transients (ANTs), and CLAGNs, we studied the variation in MIR color (W1 − W2) after subtracting the quiescent fluxes using NEOWISE-R data. The MIR color of TDEs and ANTs turns red faster than CLAGNs during the rising phase, as the color variation rate (CVR) of TDEs and ANTs is generally ≳0.2 mag yr−1, whereas that of CLAGNs is generally ≲0.3 mag yr−1. This may be caused by the difference between the ultraviolet light curves of TDEs/ANTs and CLAGNs, or be related to no or weak underlying AGN in TDEs/ANTs. In addition, TDEs have a redder color than ANTs at the earliest phase. Based on CVR, we selected high-probability TDE, ANT, and CLAGN candidates from MIR outbursts in samples of Jiang et al. and Masterson et al. We found that both samples are mixtures of TDEs/ANTs and CLAGNs. For MIR outbursts whose hosts are not Seyfert galaxies, we estimated that ∼50%–80% are TDEs and inferred a rate of infrared TDEs of 1.5–2.8 × 10−5 galaxy−1 yr−1, comparable with that of optical TDEs; the rest are CLAGNs, suggesting the presence of weak AGNs that cannot be identified using common diagnoses. Our work opens a new door for future classification of infrared-selected transients based on only photometric data.

We hereby report the discovery of ATLAS17jrp as an extraordinary tidal disruption event (TDE) in the star-forming galaxy SDSS J162034.99+240726.5 in our recent sample of mid-infrared outbursts in nearby galaxies. Its optical/UV light curves rise to a peak luminosity of ∼1.06 × 1044 erg s−1 in about a month and then decay as t −5/3 with a roughly constant temperature around 19,000 K, and the optical spectra show a blue continuum and very broad Balmer lines with FWHM ∼ 15,000 km s−1, which gradually narrowed to 1400 km s−1 within 4 yr, all agreeing well with other optical TDEs. A delayed and rapidly rising X-ray flare with a peak luminosity of ∼1.27 × 1043 erg s−1 was detected ∼170 days after the optical peak. The high MIR luminosity of ATLAS17jrp (∼2 × 1043 erg s−1) has revealed a distinctive dusty environment with a covering factor as high as ∼0.2, which is comparable to that of a torus in active galactic nuclei but at least one order of magnitude higher than normal optical TDEs. Therefore, ATLAS17jrp turns out to be one of the rare unambiguous TDEs found in star-forming galaxies, and its high dust-covering factor implies that dust extinction could play an important role in the absence of optical TDEs in star-forming galaxies.

Optical transient surveys have led to the discovery of dozens of stellar tidal disruption events (TDEs) by massive black hole in the centers of galaxies. Despite extensive searches, X-ray follow-up observations have produced no or only weak X-ray detections in most of them. Here we report the discovery of delayed X-ray brightening around 140 days after the optical outburst in the TDE OGLE16aaa, followed by several flux dips during the decay phase. These properties are unusual for standard TDEs and could be explained by the presence of supermassive black hole binary or patchy obscuration. In either scenario, the X-rays can be produced promptly after the disruption but are blocked in the early phase, possibly by a radiation-dominated ejecta which leads to the bulk of optical and ultraviolet emission. Our findings imply that the reprocessing is important in the TDE early evolution, and X-ray observations are promising in revealing supermassive black hole binaries. The discrepancy between the optical and X-ray properties of tidal disruption events (TDE) is an unresolved issue. Here, the authors show delayed X-ray brightening after the optical flare in TDE OGLE16aaa followed by several flux dips during the decay phase that could be explained by the presence of supermassive black hole binary or patchy obscuration.

Quasar feedback is routinely invoked as an indispensable ingredient in galaxy formation models. Galactic outflows are a crucial agent of quasar feedback that frequently manifest themselves in absorption and emission lines. Measuring the size and energetics of outflows based on absorption lines remains a challenge, and integral field spectroscopy (IFS) mapping in emission lines is complementary. We present Very Large Telescope (VLT)/SINFONI IFS mapping of quasar 3C 191 at z ∼ 2, in which the outflow has been analyzed in absorption line spectroscopy. Three components are found based on the morphology and kinetics of [O iii]-emitting gas: an unshifted component, which is consistent with the systemic redshift and the location of the nucleus, a blueshifted in the north, and a redshifted in the south. The latter two components have velocities ∼600 km s−1 and projected extents of 5 and 11 kpc, respectively, suggesting a biconical outflow structure. The blueshifted component’s velocity is consistent with that derived from absorption lines. Using the electron density measured by the absorption lines and the luminosity and velocity of [O iii] outflow, we derive the mass outflow rate to be Ṁ ∼ 9.5–13.4 M⊙ yr−1 and kinetic luminosity Ėkin ∼ 2.6–3.7 × 1042 erg s−1, consistent with absorption line analyses with the VLT/X-shooter spectrum. The kinetic luminosity is only 0.01% of the bolometric luminosity, rendering a relatively weak outflow compared to typical expectation for effective feedback.

AT 2018cqh is a unique tidal disruption event (TDE) discovered in a dwarf galaxy. Both the light-curve fitting and galaxy scaling relationships suggest a central black hole mass in the range of 5.9 < logM BH/M ☉ < 6.4. The r-band peak luminosity is ∼ 1043 erg s−1, making AT 2018cqh relatively faint among known optical TDEs. A delayed X-ray brightening was found around 590 days after the optical discovery but shows an unusually long time rising to peak over at least 558 days, which could be coming from delayed accretion of a newly forming debris disk. We report the discovery of delayed radio flares around 1105 days since its discovery, characterized by an initial steep rise of ≳175 days, a flattening lasting about 544 days, and a phase with another steep rise. The rapid rise in radio flux coupled with the slow decay in the X-ray emission points to a delayed launching of outflow, perhaps due to a transition in the accretion state. However, known accretion models can hardly explain the origins of the secondary radio flare that is rising even more rapidly in comparison with the initial one. If confirmed, AT 2018cqh would be a rare faint TDE in a dwarf galaxy exhibiting optical, X-ray, and radio flares. We call for continued multifrequency radio observations to monitor its spectral and temporal evolution, which may help to reveal new physical processes that are not included in standard TDE models.

X-ray quasiperiodic eruptions (QPEs) are rare and enigmatic phenomena that increasingly show a connection to tidal disruption events (TDEs). However, the recently discovered QPEs in ZTF19acnskyy (“Ansky”) appear to be linked to an active galactic nucleus (AGN) rather than a TDE, as their slow decay and AGN-like variability differ markedly from that of typical TDEs. This finding may imply broader formation channels for QPEs. To further investigate Ansky’s nature, we obtained a timely ultraviolet (UV) spectrum, which reveals a featureless, TDE-like spectrum devoid of broad optical or UV emission lines. Additionally, the steep UV continuum, fitted by a power law with an index of −2.6, aligns more closely with TDEs than with AGNs. Compared to other featureless TDEs, Ansky exhibits a significantly lower blackbody luminosity (∼1043 erg s−1) and much longer rise/decay timescales, suggesting a distinct TDE subclass. An offset TDE involving an intermediate-mass black hole is unlikely, given its position consistent with the galactic center, with a 3σ upper limit of 54 pc. Instead, we propose that Ansky may result from the tidal disruption of a post-main-sequence star by a typical supermassive black hole. Our findings strengthen the growing evidence for TDE–QPE associations, although other formation channels for QPEs remain plausible and await future observational efforts.

Measuring the distance of quasar outflows from the central source (R) is essential for determining their importance for active galactic nucleus feedback. There are two methods to measure R: (1) a direct determination using spatially resolved integral field spectroscopy (IFS) of the outflow in emission and (2) an indirect method that uses the absorption troughs from ionic excited states. The column density ratio between the excited and resonance states yields the outflow number density. Combined with a knowledge of the outflow’s ionization parameter, R can be determined. Generally, the IFS method probes an R range of several kiloparsecs or more, while the absorption method usually yields R values of less than 1 kpc. There is no inconsistency between the two methods as the determinations come from different objects. Here we report the results of applying both methods to the same quasar outflow, where we derive consistent determinations of R ≈ 5 kpc. This is the first time that the indirect absorption R determination is verified by a direct spatially resolved IFS observation. In addition, the velocities (and energetics) from the IFS and absorption data are found to be consistent. Therefore, these are two manifestations of the same outflow. In this paper we concentrate on the absorption R determination for the outflow seen in quasar 3C 191 using Very Large Telescope/X-shooter observations. We also reanalyze an older absorption determination for the outflow based on Keck/High Resolution Echelle Spectrometer data and find the revised measurement to be consistent with ours. Our companion paper details the IFS analysis of the same object.

Introduction Our objective was to evaluate the efficacy of expanded non‐invasive prenatal testing (NIPT) that includes both trisomies and copy number variants (CNVs) in high‐risk twin pregnancies. Material and Methods A prospective, double‐blinded cohort study was conducted, enrolling 73 high‐risk twin pregnancies characterized by increased risk of genetic disorders due to factors such as increased nuchal translucency, structural anomalies, fetal growth restriction, and other factors associated with chromosomal abnormality. Participants underwent invasive karyotyping and chromosomal microarray analysis, alongside separate expanded NIPT for research purposes. The sensitivity, specificity, positive predictive value, and negative predictive value of expanded NIPT were calculated. Results The cohort included 24 monochorionic and 49 dichorionic twin pregnancies. The median cell‐free fetal DNA concentration in expanded NIPT was 16.7% (range 3.86%–49.1%), with a test failure rate of 1.4% (1/73). High‐risk findings for trisomy 21/13/18 were identified in five cases (6.8%), Turner syndrome in one case (1.4%), and CNVs indicative of high risk for clinically significant microdeletion/microduplication syndromes (MMS) in ten cases (13.7%). Of these, 56 cases (76.7%) tested NIPT negative, revealing one false‐negative for 45, X and five false‐negatives for CNVs. Expanded NIPT achieved a detection rate of 100% (5/5) for trisomy 21/13/18 with a false‐positive rate of 0% (0/5), a detection rate of 33.3% (1/3) for sex chromosome abnormalities with a false‐positive rate of 0% (0/3), and a detection rate of 66.7% (4/6) for MMS with a false‐positive rate of 3.0% (2/67). The positive predictive values for trisomy T21/13/18, sex chromosome abnormalities, and known MMS were 100% (5/5), 100% (1/1), and 66.7% (4/6) in the expanded NIPT, respectively. Conclusions The expanded NIPT demonstrated high detection rates for common trisomies and moderate detection rates for prenatal MMS in high‐risk twin pregnancies. Further studies with large sample sizes in low‐risk populations are needed. The efficacy of expanded non‐invasive prenatal testing (NIPT) in twin pregnancies has been less clear. This study presents a relatively optimistic view: expanded NIPT demonstrates high detection rates for common trisomies and moderate DRs for prenatal microdeletion/microduplication syndromes in high‐risk twin pregnancies.

AT2018cqh is a unique optical tidal disruption event (TDE) discovered in a dwarf galaxy exhibiting delayed X-ray and radio flares. We present the results from high-resolution Very Long Baseline Array and enhanced Multi Element Remotely Linked Interferometer Network radio observations of AT2018cqh extending to δt ∼ 2250 days postdiscovery, which reveal a compact radio emission, unresolved at a scale of ≲0.13 pc at 7.6 GHz, with a high brightness temperature of Tb ≳ 4.03 × 109 K. The radio spectral energy distribution (SED) is found to gradually shift toward a higher peak flux density and frequency over a period of ∼1000 days. An equipartition analysis suggests that there is little change in the radio-emitting region over this period, while the electron density increases by a factor of 3. The radio light curve at 0.89 GHz continues to rise, with a bump feature lasting for 240 days. These properties are in contrast to the predictions of the standard shock-wave model from a diffuse circumnuclear medium but could be explained if dense clouds exist in the circumnuclear environment. The latter scenario is supported by our hydrodynamic simulations of the interaction of the TDE outflow with a cloud, which can reproduce the temporal evolution in the radio SED. This work highlights the importance of outflow–cloud interaction in explaining the delayed fast-rising radio emission observed in some TDEs, especially those occurring in galaxies with preexisting active galactic nucleus activity.

Background Fetal growth restriction (FGR) is a common obstetric complication where a fetus fails to reach its genetically determined growth potential. Current diagnostic methods rely on population-based fetal biometric percentiles, which struggle to distinguish pathological FGR from healthy small-for-gestational-age (SGA) infants and may miss cases of growth restriction in fetuses with a high genetic growth potential who fall above conventional SGA thresholds. This study aimed to develop a novel diagnostic framework for FGR by incorporating individualized genetic potential modeling to improve precision in identification and risk stratification. Methods Using data from the Shanghai Birth Cohort (1,806 mother-infant pairs), fetal growth potential was calculated using a polygenic risk score for birth weight derived from fetal genome-wide association studies. A new metric, “FGR_degree,” was developed as the difference between standardized genetic growth potential and actual birth weight Z-score. Fetuses were stratified into risk categories using a dual-threshold approach: the top 10% of FGR_degree values combined with SGA criteria (birth weight < 10th percentile). The high-risk “trueFGR” group included fetuses meeting both criteria. Maternal characteristics, pregnancy complications, neonatal outcomes, and neurodevelopmental outcomes at six months were analyzed using regression models. Results Among 1,806 mother-child pairs, 181 newborns were classified into the top 10% FGR_degree group, including 46 trueFGR cases. Compared to SGA infants, trueFGR infants exhibited consistent growth impairments: lower birth weight (2,599.7 g vs. 2,720.9 g, P  = 0.02), reduced GROW centiles (4.8% vs. 5.7%, P  < 0.001), and disproportionate body proportionality. NICU admission rates were higher in trueFGR (17.4% vs. 12.5%, P  = 0.59). Neurodevelopmental outcomes showed a dose-response relationship between FGR_degree and 6-month deficits, with trueFGR conferring the highest adjusted risk for gross motor delay (OR 5.04, 95% CI [2.17, 11.69] vs. 3.51, 95% CI [1.85, 6.67] in SGA). Sensitivity analyses confirmed enhanced risk prediction by combining Top10_FGR_degree with SGA. Conclusions Integrating fetal genomic data with birth weight enabled the development of a novel FGR severity metric. Combining FGR_degree with SGA classifications improved risk stratification, identifying high-risk fetuses more precisely. TrueFGR was associated with maternal complications, adverse outcomes, and neurodevelopmental delays at six months. Future research should explore non-invasive fetal DNA profiling and multi-ethnic validation.