Kavli Affiliate: Moritz Guenther | Summary:Binary stars are the progenitors of exotic objects, such as supernovae and gravitational wave sources. However, some systems merge earlier when the primary expands into a giant star at the end of its lifetime on the main sequence and causes its companion to spiral in. TYC 4144-329-2 is a candidate […]
Kavli Affiliate: Feng Long| Summary: High-dimensional distributions can change without altering means or covariances, while the number of affected coordinates is often unknown. We propose nonparametric procedures that address both challenges through standardized rank comparisons of marginal distributions. Sum and maximum scans target dense and sparse changes, and a Cauchy combination adapts to unknown sparsity. […]
Kavli Affiliate: Alexander Ji | Summary:We report an independent identification of the ultra metal-poor (UMP) star ($rm[Fe/H] =-4.06$) $Gaia$ DR3 $textttsource_id$ 4795913112968206720 (GDR3_479591) in the $Gaia$ mission’s Blue and Red Photometer ‘XP’ spectro-photometric catalog. We combine multi-band photometry, astrometry, and high-resolution spectroscopy to confirm GDR3_479591 as a red giant-branch (RGB) star located at $sim 6,rm […]
Kavli Affiliate: Anna Frebel | Summary:We report an independent identification of the ultra metal-poor (UMP) star ($rm[Fe/H] =-4.06$) $Gaia$ DR3 $textttsource_id$ 4795913112968206720 (GDR3_479591) in the $Gaia$ mission’s Blue and Red Photometer ‘XP’ spectro-photometric catalog. We combine multi-band photometry, astrometry, and high-resolution spectroscopy to confirm GDR3_479591 as a red giant-branch (RGB) star located at $sim 6,rm […]
Kavli Affiliate: Erin Kara | Summary:Measurements of stellar-mass black hole spin probe accretion under strong gravity and constrain black hole formation and evolution. Intermediate states, in which thermal disk, coronal, and reflection emission all contribute significantly, are particularly complex environments for spin measurements and useful for probing spectral-modeling systematics. We investigate these effects using paired, […]
Kavli Affiliate: Michael McDonald | Summary:This is the second paper in a series where we examine archival far-ultraviolet spectroscopy of 29 massive elliptical galaxies from the Far Ultraviolet Spectroscopic Explorer (FUSE) with modern methods. In the first paper, we performed SED modeling with aperture-matched photometry and analyzed the young and old stellar populations in these […]
Kavli Affiliate: Subo Dong | Summary:Recent studies found a number of short-timescale microlensing events that are thought to be produced by free-floating or wide-orbit planets. The microlensing event KMT-2024-BLG-0792/OGLE-2024-BLG-0516 is currently the only free-floating planet candidate with a directly measured mass ($0.73^+0.25_-0.15$ Saturn masses), derived from joint ground-based and Gaia satellite observations. However, it remains […]
Kavli Affiliate: Luis Ho | Summary:We present a comparative analysis of long-term mid-infrared (MIR) color variations (MCVs) for 1,977 narrow-line Seyfert 1 (NLSy1) and 4,113 broad-line Seyfert 1 (BLSy1) galaxies at $z < 0.3$. Using 14 years of WISE and NEOWISE data, we quantify the correlation between $W1-W2$ color and $W1$ magnitude. We categorize sources […]
Kavli Affiliate: Catherine Grant | Summary:Time-Domain and Multi-Messenger Astrophysics (TDAMM) is entering a discovery-rich but follow-up-limited era, creating an urgent need for responsive, multiwavelength space-based capabilities. The Hydra constellation is a concept for a proliferated space architecture for time-domain astrophysics. The constellation would act as a disaggregated observatory composed of coordinated, relatively low-cost spacecraft that […]
Kavli Affiliate: Roberto Maiolino | Summary:We present a clustering-based method for inferring halo masses of high-redshift galaxies, validated using the COLIBRE simulations combined with the HOMA empirical model, which assumes star formation to be proportional to halo accretion rate and is calibrated to JWST observations. Our approach matches the two-point correlation function of galaxies in […]