arXiv subjects

Yuhan Wen

Publications and source records attributed to Yuhan Wen.

7 recordsLinked to original sources

arXiv2026

Probing the Future of Meta-Analysis: Eliciting Design Principles via an Agentic Research IDE

Meta-analyses and systematic reviews demand rigorous abductive reasoning to build, test, and refine hypotheses across vast, heterogeneous literature. While NLP advancements have automated parts of this pipeline, existing tools often detach researchers from the cognitive loop or function merely as retrieval engines, leading to loss of intellectual ownership and frequent context switching. We present Research IDE, a prototype reimagining authoring environments through the "Research as Code" metaphor. Research IDE embeds a multi-agent backend into the writing flow, enabling in-situ verification via "hypothesis breakpoints." A one-week field deployment with 8 domain experts, followed by a reflective workshop, as a Research through Design (RtD) probe, reveals that users strongly preferred this verification workflow, actively leveraged prior knowledge for confirmation, and reported that breakpoints sparked insights. Drawing from participant feedback and suggestions, we derive design implications for future AI-assisted research tools that fully preserve researcher autonomy and intellectual ownership while harnessing computational scale.

cs.HC↗

arXiv2026

Evidence of Gas Depletion in Quasars with Moderate Radio Emission

The energy released by active galactic nuclei (AGNs) is considered to have a profound impact on the cold gas properties of their host galaxies, potentially heating or removing the gas and further suppressing star formation. To understand the feedback from AGN radio activity, we investigate its impacts on the cold gas reservoirs in AGNs with different radio activity levels. We construct a quasar sample with a mean $z\sim1.5$ and a mean $L_{\rm bol}\sim10^{45.8}\ \rm erg\ s^{-1}$, all with Herschel detections to enable estimates of the total gas mass through the galactic dust continuum emission. The sample is then cross-matched with radio catalogs and divided into radio loud (RL) quasars, radio-detected radio quiet (RQ) quasars and radio-undetected quasars based on their radio loudness. Through spectral energy distribution (SED) fitting, we find the radio-detected RQ quasars exhibit evidence of gas deficiency with host galaxies possessing $\sim 0.3$ dex lower dust and gas masses compared to the other two groups, despite being matched in $M_{\rm BH}$, $L_{\rm bol}$, $M_{*}$ and SFR. Furthermore, evidence from optical spectra shows that both the fraction and velocity of outflows are higher in the radio-detected RQ group, suggesting a connection between the ionized gas outflows and the moderate radio activity. These results suggest that the AGN feedback could be more efficient in AGNs with weak/moderate radio emission than in those without radio detection or those with strong radio emission. Further high-resolution observations are needed to understand the interaction between the interstellar medium and the weak/moderate AGN radio activity.

astro-ph.GA↗

arXiv2025

The UV/optical Continuum Reverberation Mapping of Eight Active Galactic Nuclei with Swift: Further Evidence for the Outer Component

In our previous work, we applied the ICCF-Cut method to the continuum reverberation mapping (CRM) of six active galactic nuclei (AGNs) based on the published Swift data. Extending this work, we perform a systematic AGN CRM study utilizing the Swift archive. We enlarge our sample with eight additional AGNs at $z<0.05$ with high-cadence ($<3$ days) and multiband photometric observations. Time series analysis of these light curves shows two main results: (1) The interband lags are broadly consistent with $τ\propto λ^{4/3}$, while the average interband lags are larger than those predicted by the standard thin accretion disk model. (2) For most targets, there exists a $U$ band lag excess, which is probably due to the diffuse continuum emission from the broad-line region (BLR). We employ the ICCF-Cut method to extract the possible diffuse continuum component from the $U$ band light curves and calculate the diffuse continuum lags ($τ_{\rm cut}$), which are generally consistent with the lags ($τ_{\rm jav}$) derived by the JAVELIN Photometric Reverberation Mapping Model. Further analysis with our sample indicates a positive correlation between the diffuse continuum region size and the BLR size ($R_{\rm DCR}-R_{\rm BLR}$ relation), as well as another correlation with the luminosity ($R_{\rm DCR}-L$ relation). These findings provide further evidence for a significant contribution of diffuse continuum emission from the BLR to the AGN continuum lags.

astro-ph.GA↗

arXiv2024

H$α$ Reverberation Mapping from Broad-band Photometry of Dwarf Seyfert 1 Galaxy NGC 4395

NGC 4395 is a dwarf Seyfert 1 galaxy with a possible intermediate-mass black hole of several $\rm{10^4}$ solar masses in its center. As a well-studied object, its broad line region size has been measured via H$\rmα$ time lag in numerous spectroscopic reverberation mapping (SRM) and narrow-band photometric reverberation mapping (PRM) campaigns. Here we present its H$\rmα$ time lag measurement using broad-band photometric data, with the application of our newly-developed ICCF-Cut method as well as the JAVELIN and $χ^2$ methods. utilizing the minute-cadence multi-band light curves obtained from the $\rm{2}$m FTN and $\rm{10.4}$m GTC telescopes in recent works, we measured its H$\rmα$ lag as approximately $40 \sim 90$ minutes from broad-band PRM. With the H$\rmα$ emission line velocity dispersion, we calculated its central black hole mass as $\rm M_{\rm BH} = (8\pm4) \times 10^3\, M_{\rm \odot}$. These results are comparable with previous results obtained by narrow-band PRM and SRM, providing further support to an intermediate-mass black hole in NGC 4395. In addition, our study also validates the ICCF-Cut as an effective method for broad-band PRM, which holds the potential for widespread application in the era of large multi-epoch, high-cadence photometric surveys.

astro-ph.GA↗

arXiv2024

Evidence for an Outer Component in the Continuum Reverberation Mapping of Active Galactic Nuclei

The continuum reverberation mapping is widely used in studying accretion disk of active galactic nuclei (AGN). While some indirect evidence and simulations indicated that the diffuse continuum, especially the strong Balmer continuum from the broad line region (BLR), may contribute to the continuum in the u/U band. Here, we present direct evidence for this contribution. In this work, we apply the ICCF-Cut method to continuum reverberation mapping to extract the possible diffuse continuum light curves of 6 AGNs with high cadence, high quality and multi-band observations. We find the existence of an outer component out of the accretion disk for each of 6 AGNs in the Swift U band. Meanwhile, similar results can be derived by JAVELIN Photometric Reverberation Mapping Model for 4 of them. The lags of the outer components are consistent with the predicted Balmer continuum lags, which are about half of the H$β$ lag values. Our result directly reinforces that an outer component, especially the Balmer continuum in the rest-frame u/U band, can contribute significantly to the continuum reverberation lags of AGNs.

astro-ph.GA↗

arXiv2024

H$α$ Time Delays of AGNs from the Zwicky Transcient Facility Broadband Photometry

In our previous work on broadband photometric reverberation mapping (PRM), we proposed the ICCF-Cut process to obtain the time lags of H$α$ emission line from two broadband lightcurves via subtracting the continuum emission from the line band. Extending the work, we enlarge our sample to the Zwicky Transient Facility (ZTF) database. We adopt two criteria to select 123 type 1 AGNs with sufficient variability and smooth lightcurves from 3537 AGNs at $z<0.09$ with more than 100 epoch observations in the $g$ and $r$ bands from the ZTF database. We calculate the H$α$ time lags for 23 of them which have previous spectroscopic reverberation mapping (SRM) results using ICCF-Cut, JAVELIN and $χ^2$ methods. Our obtained H$α$ time lags are slightly larger than the H$β$ time lags, which is consistent with the previous SRM results and the theoretical model of the AGN broad line region. The comparisons between SRM and PRM lag distributions and between the subtracted emission line lightcurves indicate that after selecting AGNs with the two criteria, combining the ICCF-Cut, JAVELIN and $χ^2$ methods provides an efficient way to get the reliable H$α$ lags from the broadband PRM. Such techniques can be used to estimate the black hole masses of a large sample of AGNs in the large multi-epoch photometric sky surveys such as the Legacy Survey of Space and Time (LSST) and the survey from the Wide Field Survey Telescope (WFST) in the near future.

astro-ph.GA↗

arXiv2023

The H$α$ broadband photometric reverberation mapping of four Seyfert 1 galaxies

Broadband photometric reverberation mapping (PRM) have been investigated for AGNs in recent years, but mostly on accretion disk continuum RM. Due to the small fraction of broad emission lines in the broadband, PRM for emission lines is very challenging. Here we present an ICCF-Cut method for broadband PRM to obtain the H$α$ broad line lag and apply it to four Seyfert 1 galaxies, MCG+08-11-011, NGC 2617, 3C 120 and NGC 5548. All of them have high quality broadband lightcurves with daily/sub-daily cadence, which enables us to extract H$α$ lightcurves from the line band by subtracting the contributions from the continuum and host galaxy. Their extracted H$α$ lightcurves are compared with the lagged continuum band lightcurves, as well as the lagged H$β$ lightcurves obtained by spectroscopic RM (SRM) at the same epochs. The consistency of these lightcurves and the comparison with the SRM H$β$ lags provide supports to the H$α$ lags of these AGNs, in a range from 9 to 19 days, obtained by the ICCF-Cut, JAVELIN and $χ^2$ methods. The simulations to evaluate the reliability of H$α$ lags and the comparisons between SRM H$β$ and PRM H$α$ lags indicate that the consistency of the ICCF-Cut, JAVELIN and $χ^2$ results can ensure the reliability of the derived H$α$ lags. These methods may be used to estimate the broad line region sizes and black hole masses of a large sample of AGNs in the large multi-epoch high cadence photometric surveys such as LSST in the future.

astro-ph.GA↗