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2024

1. Prato, L., Kutra, T., Tofflemire, B., Schaefer, G., Akeson, R., Segura-Cox, D., Kraus, A., Knowlton, P., Hyden, J., Johns-Krull, C., Andrews, S., Jensen, E., 2024, AAS, 56, 202.05, Should I Stay or Should I Go: What Governs Circumstellar Disk Lifetimes
   Abstract

   Primordial disks around young stars are the demonstrated sites of planet formation, yet the qualities supporting disk longevity and the triggers driving disk dissipation are poorly understood. Circumstellar disks in pre-main sequence binary systems provide ideal environments within which to analyze disk properties as a function of stellar characteristics. We present early results from our unique high-angular resolution program which combines (1) millimeter imaging of circumstellar disks with ALMA and (2) near-infrared, component-resolved, R=30,000 spectroscopy of the young stars with Keck+NIRSPEC for binaries with at least partially determined orbits. By controlling for orbital parameters, we highlight the relationships between the properties of circumstellar disks (e.g., radial extent, substructure, inclination) and stars (e.g., veiling, rotation period, magnetic field strength). In the eccentric, 0.1" quasi-twin DF Tau binary, two circumstellar disks are detected with ALMA but one disk is actively accreting while the other appears to have decoupled from a rapidly rotating central star. Another twin system, the 0.2" low-eccentricity FO Tau binary, shows well-aligned orbital and disk inclinations, and modest stellar rotation and near-infrared excess veiling in both components. This research was supported in part by NSF awards AST-1313399 and AST-2109179.

2. Horch, E., Wolf, M., Smith, M., Anderson, L., Baculima, A., Jurgella, K., Broadbridge, C., Mansfield, A., van Belle, G., 2024, AAS, 56, 204.02, Introducing IFUSI: the Integral Field Unit Speckle Imager
   Abstract

   We discuss preliminary design work and prototyping for IFUSI, the Integral Field Unit Speckle Imager. This instrument, planned as a visitor instrument at the 4.3-m Lowell Discovery Telescope, will use a ~2500-fiber integral field unit to record spectra over a highly-magnified ~1.1x1.1-arcsecond field of view. From these spectra, it will be possible to reconstruct speckle patterns at all wavelengths through the visible range, after which the patterns can be reduced and analyzed in the standard way to produce diffraction-limited images. This will make IFUSI the first truly pan-chromatic speckle imager to be built. In addition to discussing the progress on the project to date, we will detail the data reduction philosophy we plan to employ, and also educational and public outreach activities associated with the project. Finally, the science enabled with the instrument at Lowell will be outlined, including definitive determinations of which star an exoplanet obits in close binary systems that host exoplanets.

   We gratefully acknowledge support from National Science Foundation grants AST-2206099 and AST-2206100 in the completion of this work.

3. Levine, S., 2024, AAS, 56, 318.04, Lowell Observatory, 130 Years Young
   Abstract

   Lowell Observatory is a private, independent non-profit institution. Its mission today, as it was when it was founded in 1894, is to pursue the study of astronomy and to bring the results of astronomical research to the general public. Over the years, Lowell has gone through several cycles of change. This talk will focus on how the continuity of mission aims has enabled Lowell to productively repurpose older research equipment (like the Clark 24inch telescope, and the glass plate archive) in support of outreach and unforeseen research ideas. At the same time, Lowell is also integrating modern tools in the all aspects of the research (the 4.3-m Lowell Discovery Telescope) and outreach mission (the Giovale Open Deck Observatory and the coming Astronomy Discovery Center); Lowell remains a vibrant center of both research and outreach.

4. Hunter, D., 2024, AAS, 56, 321.01, HI and star formation in nearby dwarf irregular galaxies
   Abstract

   Dwarf irregular (dIrr) galaxies are not just small versions of spiral galaxies. They are gas-dominated but with low gas density overall and with thick disk structure and high gas porosity. These properties have consequences for the formation of clouds that produce new stars. Yet, young stars can be found not only in the central regions of dIrrs, but in their far outer disks where gas densities are very low. I will discuss four possible drivers for cloud formation in dIrrs and the complications with each in explaining the star formation found in typical, isolated dIrrs.

5. Burgasser, A., Brooks, H., Alvarado, E., Gerasimov, R., Schneider, A., Meisner, A., Caselden, D., Rothermich, A., Bickle, T., Kabatnik, M., Softich, E., Karpoor, P., Faherty, J., Kirkpatrick, J., Kuchner, M., 2024, AAS, 56, 406.01, A Hypervelocity L Subdwarf Passing Through the Solar Neighborhood
   Abstract

   We report the discovery of a very high velocity metal-poor L subdwarf whose kinematics indicate that it is escaping the Milky Way. The source, CWISE J1249+3621, was discovered by citizen scientists as part of the Backyard Worlds: Planet 9 program as a high proper motion ( = 1.03 arcsec/yr) faint red source. Moderate resolution spectroscopy obtained with Keck/NIRES reveals it to be a metal-poor early L subdwarf with a high radial velocity (-103 km/s). With an estimated distance of 140 pc, CWISE J1249+3621 has a total speed of at least 600 km/s, exceeding the local Galactic escape velocity. Remarkably, the source is moving radially inward, suggesting it was ejected from a globular cluster located in outer Galactic plane in the past 10-30 Myr. CWISE J1249+3621 is the first very low mass star - and the nearest system - found to have an extragalactic trajectory, and may represent a broader population of high-velocity, low-mass ejections from dense cluster systems.

6. Alvarado, E., Gerasimov, R., Burgasser, A., Brooks, H., Aganze, C., 2024, AAS, 56, 406.04, Probing the Early History of the Milky Way with New Models of Metal-poor Brown Dwarfs
   Abstract

   Ultracool Dwarfs (UCDs) are stars and brown dwarfs with surface temperatures 3000K and masses 0.1 solar. The atmospheres of UCDs are dominated by molecular opacity and chemistry, rendering their spectra highly sensitive to element abundances. In combination with appropriate stellar models with non-solar chemistry, UCDs may be used as chemical tracers of stellar populations.

   Metal-poor UCDs are particularly interesting, as they represent the poorly understood early phases of the chemical evolution of the Milky Way. However, few metal-poor UCD stellar models are available in the literature. We present a new grid of evolutionary models and model atmospheres for metal-poor UCDs. Our models were calculated using the PHOENIX code, version 15, and include the Allard & Homeier treatment of clouds with gravitational settling. The atmosphere grid extends down to 700 K in effective temperature, and spans metallicities ([Fe/H]) from -2.4 to 0.3 dex for multiple values of -enhancement. The corresponding evolutionary models and synthetic isochrones were calculated with the MESA code, using our model atmospheres as atmosphere-interior boundary conditions.

   These new models will support studies of metal-poor UCDs discovered by deep surveys with the James Webb Space Telescope, the Nancy Grace Roman Space Telescope, and the Vera Rubin Observatory, as well as new photometric surveys of UCDs in globular clusters.

7. Shah, P., Davis, T., Bacon, D., Brout, D., Frieman, J., Galbany, L., Kessler, R., Lahav, O., Lee, J., Lidman, C., Nichol, R., Sako, M., Sanchez, B., Scolnic, D., Sullivan, M., Vincenzi, M., Wiseman, P., Allam, S., Abbott, T., Aguena, M., Alves, O., Andrade-Oliveira, F., Annis, J., Bechtol, K., Bertin, E., Bocquet, S., Brooks, D., Carnero Rosell, A., Carretero, J., Castander, F., da Costa, L., Pereira, M., Diehl, H., Doel, P., Doux, C., Everett, S., Ferrero, I., Flaugher, B., Friedel, D., Gatti, M., Gruen, D., Gruendl, R., Gutierrez, G., Hinton, S., Hollowood, D., Honscheid, K., Huterer, D., James, D., Kuehn, K., Lee, S., Marshall, J., Mena-Fernandez, J., Miquel, R., Myles, J., Ogando, R., Palmese, A., Pieres, A., Roodman, A., Sanchez, E., Sevilla-Noarbe, I., Smith, M., Soares-Santos, M., Suchyta, E., Swanson, M., Tarle, G., Weaverdyck, N., 2024, MNRAS, The Dark Energy Survey : Detection of weak lensing magnification of supernovae and constraints on dark matter haloes
   Abstract

   The residuals of the distance moduli of Type Ia supernovae (SN Ia) relative to a Hubble diagram fit contain information about the inhomogeneity of the universe, due to weak lensing magnification by foreground matter. By correlating the residuals of the Dark Energy Survey Year 5 SN Ia sample (DES-SN5YR) with extra-galactic foregrounds from the DES Y3 Gold catalog, we detect the presence of lensing at 6.0 significance. This is the first detection with a significance level above 5. Constraints on the effective mass-to-light ratios and radial profiles of dark-matter haloes surrounding individual galaxies are also obtained. We show that the scatter of SNe Ia around the Hubble diagram is reduced by modifying the standardisation of the distance moduli to include an easily calculable de-lensing (i.e., environmental) term. We use the de-lensed distance moduli to recompute cosmological parameters derived from SN Ia, finding in Flat wCDM a difference of _M = +0.036 and w = -0.056 compared to the unmodified distance moduli, a change of ~0.3. We argue that our modelling of SN Ia lensing will lower systematics on future surveys with higher statistical power. We use the observed dispersion of lensing in DES-SN5YR to constrain ₈, but caution that the fit is sensitive to uncertainties at small scales. Nevertheless, our detection of SN Ia lensing opens a new pathway to study matter inhomogeneity that complements galaxy-galaxy lensing surveys and has unrelated systematics.

8. Porter, S., Benecchi, S., Verbiscer, A., Grundy, W., Noll, K., Parker, A., 2024, PSJ, 5, 143, Detection of Close Kuiper Belt Binaries with HST WFC3
   Abstract

   Binaries in the Kuiper Belt are common. Here we present our analysis of the Solar System Origins Legacy Survey (SSOLS) to show that using a point-spread function (PSF)-fitting method can roughly double the number of binaries identified in that data set. Out of 198 Kuiper Belt objects (KBOs) observed by SSOLS, we find 23 to be visually separated binaries, while a further 19 are blended PSF binaries detectable with the method we present here. This is an overall binary fraction of 21% for the SSOLS data set of cold classical KBOs. In addition, we tested our fitting methods on synthetic data, and while we were able to show them to be very effective at detecting certain blended-PSF binary KBOs, fainter or closer binary KBOs may easily be missed, suggesting that the close binary KBO fraction could be even higher. These results strongly support the idea that most (if not all) KBOs were formed through the streaming instability process, and as a consequence, most KBOs were formed as near-equal mass binaries.

9. Kawata, D., Kawahara, H., Gouda, N., Secrest, N., Kano, R., Kataza, H., Isobe, N., Ohsawa, R., Usui, F., Yamada, Y., Graham, A., Pettitt, A., Asada, H., Baba, J., Bekki, K., Dorland, B., Fujii, M., Fukui, A., Hattori, K., Hirano, T., Kamizuka, T., Kashima, S., Kawanaka, N., Kawashima, Y., Klioner, S., Kodama, T., Koshimoto, N., Kotani, T., Kuzuhara, M., Levine, S., Majewski, S., Masuda, K., Matsunaga, N., Miyakawa, K., Miyoshi, M., Morihana, K., Nishi, R., Notsu, Y., Omiya, M., Sanders, J., Tanikawa, A., Tsujimoto, M., Yano, T., Aizawa, M., Arimatsu, K., Biermann, M., Boehm, C., Chiba, M., Debattista, V., Gerhard, O., Hirabayashi, M., Hobbs, D., Ikenoue, B., Izumiura, H., Jordi, C., Kohara, N., Loffler, W., Luri, X., Mase, I., Miglio, A., Mitsuda, K., Newswander, T., Nishiyama, S., Obuchi, Y., Ootsubo, T., Ouchi, M., Ozaki, M., Perryman, M., Prusti, T., Ramos, P., Read, J., Rich, R., Schonrich, R., Shikauchi, M., Shimizu, R., Suematsu, Y., Tada, S., Takahashi, A., Tatekawa, T., Tatsumi, D., Tsujimoto, T., Tsuzuki, T., Urakawa, S., Uraguchi, F., Utsunomiya, S., Van Eylen, V., van Leeuwen, F., Wada, T., Walton, N., 2024, PASJ, 76, 386, JASMINE: Near-infrared astrometry and time-series photometry science
   Abstract

   The Japan Astrometry Satellite Mission for INfrared Exploration (JASMINE) is a planned M-class science space mission by the Institute of Space and Astronautical Science, the Japan Aerospace Exploration Agency. JASMINE has two main science goals. One is Galactic archaeology with a Galactic Center survey, which aims to reveal the Milky Way's central core structure and formation history from Gaia-level (~25 ${\mu} $as) astrometry in the near-infrared (NIR) H_w band (1.0-1.6 ${\mu} $m). The other is an exoplanet survey, which aims to discover transiting Earth-like exoplanets in the habitable zone from NIR time-series photometry of M dwarfs when the Galactic Center is not accessible. We introduce the mission, review many science objectives, and present the instrument concept. JASMINE will be the first dedicated NIR astrometry space mission and provide precise astrometric information on the stars in the Galactic Center, taking advantage of the significantly lower extinction in the NIR. The precise astrometry is obtained by taking many short-exposure images. Hence, the JASMINE Galactic Center survey data will be valuable for studies of exoplanet transits, asteroseismology, variable stars, and microlensing studies, including discovery of (intermediate-mass) black holes. We highlight a swath of such potential science, and also describe synergies with other missions.

10. Reddy, V., Kelley, M., Benner, L., Dotson, J., Erasmus, N., Farnocchia, D., Linder, T., Masiero, J., Thomas, C., Bauer, J., Alarcon, M., Bacci, P., Bamberger, D., Battle, A., Benkhaldoun, Z., Betti, G., Birlan, M., Brozovic, M., Burt, B., Cantillo, D., Chandra, S., Chomette, G., Coates, A., DeMeo, F., Devogele, M., Fatka, P., Ferrais, M., Fini, P., van Gend, C., Giorgini, J., Glamazda, D., Holmes, R., Hora, J., Horiuchi, S., Hornoch, K., Iozzi, M., Jacques, C., Jehin, E., Jiang, H., Kaiser, G., Kusnirak, P., Kuznetsov, E., de Leon, J., Liakos, A., Licandro, J., Lister, T., Liu, J., Lopez-Oquendo, A., Maestripieri, M., Mathias, D., Micheli, M., Naidu, S., Nastasi, A., Nedelcu, A., Petrescu, E., Popescu, M., Potter, S., Pravec, P., Sanchez, J., Santana-Ros, T., Serra-Ricart, M., Sioulas, N., Sonka, A., Squilloni, A., Tombelli, M., Trelia, M., Trilling, D., Warner, E., Wells, G., Wheeler, L., Wiles, M., 2024, PSJ, 5, 141, 2023 DZ2 Planetary Defense Campaign
    Abstract

    We present the results of a fourth planetary defense exercise, focused this time on the small near-Earth asteroid (NEA) 2023 DZ2 and conducted during its close approach to the Earth in 2023 March. The International Asteroid Warning Network (IAWN), with support from NASA's Planetary Defense Coordination Office (PDCO), has been coordinating planetary defense observational campaigns since 2017 to test the operational readiness of the global planetary defense capabilities. The last campaign focused on the NEA Apophis, and an outcome of that exercise was the need for a short burst campaign to replicate a real-life near-Earth object impact hazard scenario. The goal of the 2023 DZ2 campaign was to characterize the small NEA as a potential impactor and exercise the planetary defense system including observations, hypothetical risk assessment and risk prediction, and hazard communication with a short notice of just 24 hr. The entire campaign lasted about 10 days. The campaign team was divided into several working groups based on the characterization method: photometry, spectroscopy, thermal IR photometry and optical polarimetry, radar, and risk assessment. Science results from the campaign show that 2023 DZ2 has a rotation period of 6.2745 0.0030 minutes; visible wavelength color photometry/spectroscopy/polarimetry and near-IR spectroscopy all point to an E-type taxonomic classification with surface composition analogous to aubrite meteorites; and radar observations show that the object has a diameter of 30 10 m, consistent with the high albedo (0.49) derived from polarimetric and thermal IR observations.

11. Sanchez, J., Reddy, V., Thirouin, A., Bottke, W., Kareta, T., De Florio, M., Sharkey, B., Battle, A., Cantillo, D., Pearson, N., 2024, PSJ, 5, 131, The Population of Small Near-Earth Objects: Composition, Source Regions, and Rotational Properties
    Abstract

    The study of small (<300 m) near-Earth objects (NEOs) is important because they are more closely related than larger objects to the precursors of meteorites that fall on Earth. Collisions of these bodies with Earth are also more frequent. Although such collisions cannot produce massive extinction events, they can still produce significant local damage. Here we present the results of a photometric and spectroscopic survey of small NEOs that include near-infrared spectra of 84 objects with a mean diameter of 126 m and photometric data of 59 objects with a mean diameter of 87 m. We found that S-complex asteroids are the most abundant among the NEOs, comprising 66% of the sample. Most asteroids in the S-complex were found to have compositions consistent with LL-chondrites. Our study revealed the existence of NEOs with spectral characteristics similar to those in the S-complex but that could be hidden within the C- or X-complex due to their weak absorption bands. We suggest that the presence of metal or shock darkening could be responsible for the attenuation of the absorption bands. These objects have been grouped into a new subclass within the S-complex called Sx-types. The dynamical modeling showed that 83% of the NEOs escaped from the ₆ resonance, 16% from the 3:1, and just 1% from the 5:2 resonance. Lightcurves and rotational periods were derived from the photometric data. No clear trend between the axis ratio and the absolute magnitude or rotational period of the NEOs was found.

12. Toribio San Cipriano, L., De Vicente, J., Sevilla-Noarbe, I., Hartley, W., Myles, J., Amon, A., Bernstein, G., Choi, A., Eckert, K., Gruendl, R., Harrison, I., Sheldon, E., Yanny, B., Aguena, M., Allam, S., Alves, O., Bacon, D., Brooks, D., Campos, A., Carnero Rosell, A., Carretero, J., Castander, F., Conselice, C., da Costa, L., Pereira, M., Davis, T., Desai, S., Diehl, H., Doel, P., Ferrero, I., Frieman, J., Garcia-Bellido, J., Gaztanaga, E., Giannini, G., Hinton, S., Hollowood, D., Honscheid, K., James, D., Kuehn, K., Lee, S., Lidman, C., Marshall, J., Mena-Fernandez, J., Menanteau, F., Miquel, R., Palmese, A., Pieres, A., Plazas Malagon, A., Roodman, A., Sanchez, E., Smith, M., Soares-Santos, M., Suchyta, E., Swanson, M., Tarle, G., Vincenzi, M., Weaverdyck, N., Wiseman, P., DES Collaboration, 2024, A&A, 686, A38, Dark Energy Survey Deep Field photometric redshift performance and training incompleteness assessment
    Abstract

    Context. The determination of accurate photometric redshifts (photo-zs) in large imaging galaxy surveys is key for cosmological studies. One of the most common approaches is machine learning techniques. These methods require a spectroscopic or reference sample to train the algorithms. Attention has to be paid to the quality and properties of these samples since they are key factors in the estimation of reliable photo-zs.
    Aims: The goal of this work is to calculate the photo-zs for the Year 3 (Y3) Dark Energy Survey (DES) Deep Fields catalogue using the Directional Neighborhood Fitting (DNF) machine learning algorithm. Moreover, we want to develop techniques to assess the incompleteness of the training sample and metrics to study how incompleteness affects the quality of photometric redshifts. Finally, we are interested in comparing the performance obtained by DNF on the Y3 DES Deep Fields catalogue with that of the EAzY template fitting approach.
    Methods: We emulated - at a brighter magnitude - the training incompleteness with a spectroscopic sample whose redshifts are known to have a measurable view of the problem. We used a principal component analysis to graphically assess the incompleteness and relate it with the performance parameters provided by DNF. Finally, we applied the results on the incompleteness to the photo-z computation on the Y3 DES Deep Fields with DNF and estimated its performance.
    Results: The photo-zs of the galaxies in the DES deep fields were computed with the DNF algorithm and added to the Y3 DES Deep Fields catalogue. We have developed some techniques to evaluate the performance in the absence of "true" redshift and to assess the completeness. We have studied the tradeoff in the training sample between the highest spectroscopic redshift quality versus completeness. We found some advantages in relaxing the highest-quality spectroscopic redshift requirements at fainter magnitudes in favour of completeness. The results achieved by DNF on the Y3 Deep Fields are competitive with the ones provided by EAzY, showing notable stability at high redshifts. It should be noted that the good results obtained by DNF in the estimation of photo-zs in deep field catalogues make DNF suitable for the future Legacy Survey of Space and Time (LSST) and Euclid data, which will have similar depths to the Y3 DES Deep Fields.

    The data are available at https://des.ncsa.illinois.edu/releases/y3a2/Y3deepfields

13. Archer, H., Hunter, D., Elmegreen, B., Rubio, M., Cigan, P., Windhorst, R., Cortes, J., Jansen, R., 2024, AJ, 167, 274, Probing the Relationship Between Early Star Formation and CO in the Dwarf Irregular Galaxy WLM with JWST
    Abstract

    WolfLundmarkMelotte (WLM) is a Local Group dwarf irregular (dIrr) galaxy with a metallicity 13% of solar. At 1 Mpc, the relative isolation of WLM provides a unique opportunity to investigate the internal mechanisms of star formation at low metallicities. The earliest stages of star formation in larger spirals occur in embedded clusters within molecular clouds, but dIrrs lack the dust, heavy metals, and organized structure of spirals believed necessary to collapse the molecular clouds into stars. Despite actively forming stars, the early stages of star formation in dIrrs is not well understood. We examine the relationship between early star formation and molecular clouds at low metallicities. We utilize ALMA-detected CO cores, JWST near-infrared (NIR) images (F090W, F150W, F250M, and F430M), and GALEX far-ultraviolet (FUV) images of WLM to trace molecular clouds, early star formation, and longer star formation timescales respectively. We compare clumps of NIR-bright sources (referred to as objects) categorized into three types based on their proximity to FUV sources and CO cores. We find objects, independent of their location, have similar colors and magnitudes and no discernible difference in temperature. However, we find that objects near CO have higher masses than objects away from CO, independent of proximity to FUV. Additionally, objects near CO are coincident with Spitzer 8 m sources at a higher frequency than objects elsewhere in WLM. This suggests objects near CO may be embedded star clusters at an earlier stage of star formation, but accurate age estimates for all objects are required for confirmation.

14. Speckert, M., Massey, P., Skiff, B., 2024, AJ, 167, 262, The Stellar Content of the Young Open Cluster Berkeley 50 (IC 1310)
    Abstract

    We observed the Galactic open cluster Berkeley 50 in order to determine its stellar content, distance, and age. We obtained UBV photometry of 1145 stars in a 12.'3 12.'3 field, and used Gaia proper motions and parallaxes to identify 64 members, of which we obtained spectra of the 17 brightest members. The majority of the observed population we classified as B dwarfs, with the exception of a newly identified red supergiant star, which our spectroscopy shows has a B-type companion. Our study establishes the distance as 3.8 kpc, with an average color-excess E(B V) = 0.9. Comparison of the physical properties of the cluster with the Geneva evolutionary tracks places the age of the cluster as 5060 Myr, with its most massive members being 7M

15. Malik, U., Sharp, R., Penton, A., Yu, Z., Martini, P., Tucker, B., Davis, T., Lewis, G., Lidman, C., Aguena, M., Alves, O., Annis, J., Asorey, J., Bacon, D., Brooks, D., Carnero Rosell, A., Carretero, J., Cheng, T., da Costa, L., Pereira, M., De Vicente, J., Doel, P., Ferrero, I., Frieman, J., Giannini, G., Gruen, D., Gruendl, R., Hinton, S., Hollowood, D., James, D., Kuehn, K., Marshall, J., Mena-Fernandez, J., Menanteau, F., Miquel, R., Ogando, R., Palmese, A., Pieres, A., Plazas Malagon, A., Reil, K., Romer, A., Sanchez, E., Schubnell, M., Smith, M., Suchyta, E., Swanson, M., Tarle, G., To, C., Weaverdyck, N., Wiseman, P., 2024, MNRAS, 531, 163, OzDES Reverberation Mapping Program: Stacking analysis with H, Mg II, and C IV
    Abstract

    Reverberation mapping is the leading technique used to measure direct black hole masses outside of the local Universe. Additionally, reverberation measurements calibrate secondary mass-scaling relations used to estimate single-epoch virial black hole masses. The Australian Dark Energy Survey (OzDES) conducted one of the first multi-object reverberation mapping surveys, monitoring 735 AGN up to z ~ 4, over 6 years. The limited temporal coverage of the OzDES data has hindered recovery of individual measurements for some classes of sources, particularly those with shorter reverberation lags or lags that fall within campaign season gaps. To alleviate this limitation, we perform a stacking analysis of the cross-correlation functions of sources with similar intrinsic properties to recover average composite reverberation lags. This analysis leads to the recovery of average lags in each redshift-luminosity bin across our sample. We present the average lags recovered for the H, Mg II, and C IV samples, as well as multiline measurements for redshift bins where two lines are accessible. The stacking analysis is consistent with the Radius-Luminosity relations for each line. Our results for the H sample demonstrate that stacking has the potential to improve upon constraints on the R-L relation, which have been derived only from individual source measurements until now.

16. Zhang, Y., Golden-Marx, J., Ogando, R., Yanny, B., Rykoff, E., Allam, S., Aguena, M., Bacon, D., Bocquet, S., Brooks, D., Carnero Rosell, A., Carretero, J., Cheng, T., Conselice, C., Costanzi, M., da Costa, L., Pereira, M., Davis, T., Desai, S., Diehl, H., Doel, P., Ferrero, I., Flaugher, B., Frieman, J., Gruen, D., Gruendl, R., Hinton, S., Hollowood, D., Honscheid, K., James, D., Jeltema, T., Kuehn, K., Kuropatkin, N., Lahav, O., Lee, S., Lima, M., Mena-Fernandez, J., Miquel, R., Palmese, A., Pieres, A., Plazas Malagon, A., Romer, A., Sanchez, E., Smith, M., Suchyta, E., Tarle, G., To, C., Tucker, D., Weaverdyck, N., DES Collaboration, 2024, MNRAS, 531, 510, Dark Energy Survey Year 6 results: Intra-cluster light from redshift 0.2 to 0.5
    Abstract

    Using the full 6 years of imaging data from the Dark Energy Survey, we study the surface brightness profiles of galaxy cluster central galaxies and intra-cluster light. We apply a 'stacking' method to over 4000 galaxy clusters identified by the redMaPPer cluster finder in the redshift range of 0.2-0.5. This yields high-signal-to-noise circularly averaged profile measurements of the central galaxy and intra-cluster light out to 1 Mpc from the cluster centre. Using redMaPPer richness as a cluster mass indicator, we find that the brightness of the intra-cluster light has a strong mass dependence throughout the 0.2-0.5 redshift range, and this dependence grows stronger at a larger radius. In terms of redshift evolution, we find some evidence that the central galaxy, as well as the diffuse light within the transition region between the cluster central galaxy and intra-cluster light within 80 kpc from the centre, may be growing over time. At larger radii, more than 80 kpc away from the cluster centre, we do not detect evidence of additional redshift evolution beyond the cluster mass dependence, consistent with the findings from the IllustrisTNG hydrodynamic simulation. We speculate that the major driver of intra-cluster light growth, especially at large radii, is associated with cluster mass growth. Finally, we find that the colour of the cluster central galaxy and intra-cluster light displays a radial gradient that becomes bluer at a larger radius, which is consistent with a stellar stripping and disruption origin of intra-cluster light as suggested by simulation studies.

17. Jenniskens, P., Pilorz, S., Gural, P., Samuels, D., Rau, S., Abbott, T., Albers, J., Austin, S., Avner, D., Baggaley, J., Beck, T., Blomquist, S., Boyukata, M., Breukers, M., Cooney, W., Cooper, T., De Cicco, M., Devillepoix, H., Egland, E., Fahl, E., Gialluca, M., Grigsby, B., Hanke, T., Harris, B., Heathcote, S., Hemmelgarn, S., Howell, A., Jehin, E., Johannink, C., Juneau, L., Kisvarsanyi, E., Mey, P., Moskovitz, N., Odeh, M., Rachford, B., Rollinson, D., Scott, J., Towner, M., Unsalan, O., van Wyk, R., Wood, J., Wray, J., Vaubaillon, J., Lauretta, D., 2024, Icar, 415, 116034, Lifetime of cm-sized zodiacal dust from the physical and dynamical evolution of meteoroid streams
    Abstract

    While comets eject mass mostly at cm-sizes and larger, that size range of particles is mostly absent from the interplanetary medium. Such particles are thought to be lost from the solar system by grain-grain collisions. Here, we investigate the lifetime of cm-sized meteoroids from their abundance in meteoroid streams of different age. For 487 streams, we measured the orbital element dispersions, the magnitude size distribution index, the ratio of fluffy and dense materials in the stream and their bulk densities, and the meteor light curve shape-parameter. We find that older long-period comet meteoroid streams tend to be more dispersed and evolve towards smaller semi-major axis, higher magnitude size distribution index, and contain relatively more high-density material. Meteoroids that approach the Sun closer than 0.20.3 AU are mostly young and composed of denser materials poor in sodium. We compare the observed properties of the streams to age estimates from the literature and to a set of new age estimates for long-period comet streams based on observed dispersions. We find that streams broaden with age inversely proportional to the perihelion distance (q). By selecting narrow ranges of age, we find that their magnitude distribution index changes proportional to 1/q, less steep than expected from meteoroid destruction by collisions. Instead, this shallow dependence suggests a lifetime inversely proportional to the peak grain temperature along its orbit, with the lifetime limited by thermal stresses if 0.3 < q < 1.02 AU and by sublimation if q < 0.2 AU.

17 publications and 10 citations in 2024.

17 publications and 10 citations total.