Search Publications
Empirical Color Correction to MIST and PARSEC Isochrones on Gaia BR ‑ RP and G ‑ RP with Benchmark Open Clusters
Fang, Min; Wang, Fan; Tian, Haijun +8 more
Recent literature reports a color deviation between observed Gaia color–magnitude diagrams (CMDs) and theoretical model isochrone predictions, particularly in the very low-mass regime. To assess its impact on cluster age determination via isochrone fitting, we quantified the color deviations for three benchmark clusters, Hyades, Pleiades, and Prae…
Multiwavelength Constraints on the Local Black Hole Occupation Fraction
Geha, Marla; Baldassare, Vivienne F.; Natarajan, Priyamvada +1 more
The fraction of dwarf galaxies hosting central, intermediate-mass black holes (IMBHs) at low redshifts is an important observational probe of black hole seeding at high redshift. Detections of nuclear accretion signatures in dwarf galaxies provides strong evidence for the presence of these IMBHs. We develop a Bayesian model to infer the black hole…
Dark Galactic Subhalos and the Gaia Snail
Bovy, Jo; Benson, Andrew; Frankel, Neige +1 more
Gaia has revealed a clear signal of disequilibrium in the solar neighborhood in the form of a spiral (or snail) feature in the vertical phase-space distribution. We investigate the possibility that this structure emerges from ongoing perturbations by dark
Simultaneous Multiband Photometry of the Early Optical Afterglow of GRB 240825A with Mephisto
Kumar, Brajesh; Liu, Chenxu; Wang, Tao +19 more
Gamma-ray bursts (GRBs) are the most luminous transients in the Universe. The interaction of the relativistic jet with the circumburst medium produces an afterglow and generates multiwavelength emission. In this work, we present simultaneous multiband photometry of GRB 240825A with the Multi-channel Photometric Survey Telescope (Mephisto) and anal…
Time-resolved Hubble Space Telescope UV Observations of an X-Ray Quasiperiodic Eruption Source
Wevers, T.; Arcodia, R.; Pasham, D. R. +3 more
X-ray quasiperiodic eruptions (QPEs) are a novel mode of variability in nearby galactic nuclei whose origin remains unknown. Their multiwavelength properties are poorly constrained, as studies have focused almost entirely on the X-ray band. Here, we report on time-resolved, coordinated Hubble Space Telescope far-ultraviolet (FUV) and XMM-Newton X-…
A Comprehensive Study of Type I (Thermonuclear) Bursts in the New Transient SRGA J144459.2–604207
Chen, Yupeng; Zhang, Shu; Li, Xiaobo +11 more
We report an analysis of Insight-HXMT observations of the newly discovered accreting millisecond pulsar SRGA J144459.2–604207. During the outburst, detected in 2024 February by SRG/ART-XC, the broadband persistent spectrum was well fitted by an absorbed Comptonization model. We detected 60 type I X-ray bursts in the Insight-HXMT medium energy (ME)…
Eccentricities of Close Stellar Binaries
El-Badry, Kareem; Wu, Yanqin; Hadden, Sam +2 more
Orbits of stellar binaries are in general eccentric. These eccentricities encode information about their early lives. Here, we use thousands of main-sequence binaries from the Gaia DR3 catalog to reveal that binaries inward of a few astronomical units exhibit a simple Rayleigh distribution with a mode of σe ≃ 0.3. We find the same distr…
A Diverse, Overlooked Population of Type Ia Supernovae Exhibiting Mid-infrared Signatures of Delayed Circumstellar Interaction
Burdge, Kevin B.; Sollerman, Jesper; De, Kishalay +10 more
Type Ia supernovae (SNe Ia) arise from the thermonuclear explosions of white dwarfs in multiple-star systems. A rare subclass of SNe Ia exhibit signatures of interaction with circumstellar material (CSM), allowing for direct constraints on companion material. While most known events show evidence for dense nearby CSM identified via peak-light spec…
Precise Measurements of the LMC Bar's Geometry with Gaia DR3 and a Novel Solution to Crowding-induced Incompleteness in Star Counting
Choi, Yumi; Besla, Gurtina; Olsen, Knut A. G. +1 more
We present new measurements of the 2D geometry of the LMC's stellar bar with precise astrometric observations of red clump stars in Gaia DR3. We develop a novel solution to tackle crowding-induced incompleteness in Gaia data sets with the Gaia BP-RP color excess. Utilizing the color excess information, we derive a 2D completeness map of the LMC's …
A Multiwavelength Light-curve Analysis of the Classical Nova KT Eri: Optical Contribution from a Large Irradiated Accretion Disk
Walter, Frederick M.; Kato, Mariko; Hachisu, Izumi
KT Eri is a classical nova that went into outburst in 2009. Recent photometric analysis in quiescence indicates a relatively longer orbital period of 2.6 days, so that KT Eri could host a very bright accretion disk during the outburst like in the recurrent nova U Sco, the orbital period of which is 1.23 days. We reproduced the optical V light curv…