Search Publications
NICER Monitoring of Supersoft X-Ray Sources
Luna, G. J. M.; Behar, E.; Orio, M. +9 more
We monitored four supersoft sources-two persistent ones, CAL 83 and MR Vel, and the recent novae YZ Ret (Nova Ret 2020), and V1674 Her (Nova Her 2021)-with NICER. The two persistent supersoft X-ray sources (SSS) were observed with unvaried X-ray flux level and spectrum, respectively, 13 and 20 yr after the last observations. Short-period modulatio…
A Multi-epoch, Multiwavelength Study of the Classical FUor V1515 Cyg Approaching Quiescence
Ogłoza, Waldemar; Cseh, B.; Kriskovics, L. +29 more
Historically, FU Orionis-type stars are low-mass, pre-main-sequence stars. The members of this class experience powerful accretion outbursts and remain in an enhanced accretion state for decades or centuries. V1515 Cyg, a classical FUor, started brightening in the 1940s and reached its peak brightness in the late 1970s. Following a sudden decrease…
Recurrent Strong Outbursts of an EXor-like Young Eruptive Star Gaia20eae
Ogłoza, Waldemar; Ábrahám, Péter; Kóspál, Ágnes +21 more
We present follow-up photometric and spectroscopic observations, and subsequent analysis of Gaia20eae. This source triggered photometric alerts during 2020 after showing a ~3 mag increase in its brightness. Its Gaia Alert light curve showed the shape of a typical eruptive young star. We carried out observations to confirm Gaia20eae as an eruptive …
Antaeus: A Retrograde Group of Tidal Debris in the Milky Way's Disk Plane
Martin, Nicolas; Famaey, Benoit; Viswanathan, Akshara +5 more
We present the discovery of a wide retrograde moving group in the disk plane of the Milky Way using action-angle coordinates derived from the Gaia DR3 catalog. The structure is identified from a sample of its members that are currently almost at the pericenter of their orbit and are passing through the solar neighborhood. The motions of the stars …
Dissecting Nearby Galaxies with piXedfit. II. Spatially Resolved Scaling Relations among Stars, Dust, and Gas
Tacchella, Sandro; Wu, Po-Feng; Morishita, Takahiro +5 more
We study spatially resolved scaling relations among stars, dust, and gas in ten nearby spiral galaxies. In a preceding paper, we have derived spatially resolved properties of the stellar population and dust by a panchromatic spectral energy distribution fitting using piXedfit. Now, we investigate resolved star formation ( ${{\rm{\Sigma }}}_{{{\rm{…
Strategies for Determining the Cascade Rate in MHD Turbulence: Isotropy, Anisotropy, and Spacecraft Sampling
Shay, Michael A.; Oughton, Sean; Yang, Yan +6 more
Exact laws for evaluating cascade rates, tracing back to the Kolmogorov "4/5" law, have been extended to many systems of interest including magnetohydrodynamics (MHD), and compressible flows of the magnetofluid and ordinary fluid types. It is understood that implementations may be limited by the quantity of available data and by the lack of turbul…
Clues to the Formation of Liller 1 from Modeling Its Complex Star Formation History
Pallanca, Cristina; Dalessandro, Emanuele; Ferraro, Francesco R. +7 more
Liller 1 and Terzan 5 are two massive systems in the Milky Way bulge hosting populations characterized by significantly different ages (Δt > 7-8 Gyr) and metallicities (Δ[Fe/H] ~ 1 dex). Their origin is still strongly debated in the literature and all formation scenarios proposed so far require some level of fine-tuning. The detailed star forma…
Low Star Formation Activity and Low Gas Content of Quiescent Galaxies at z = 3.5-4.0 Constrained with ALMA
Papovich, Casey; Kacprzak, Glenn G.; Glazebrook, Karl +10 more
The discovery in deep near-infrared surveys of a population of massive quiescent galaxies at z > 3 has given rise to the question of how they came to be quenched so early in the history of the universe. Measuring their molecular gas properties can distinguish between physical processes where they stop forming stars due to a lack of fuel versus …
The Active Chromospheres of Lithium-rich Red Giant Stars
Dupree, Andrea K.; Mahadevan, Suvrath; Terrien, Ryan +17 more
We have gathered near-infrared zyJ-band high-resolution spectra of nearly 300 field red giant stars with known lithium abundances in order to survey their He I λ10830 absorption strengths. This transition is an indicator of chromospheric activity and/or mass loss in red giants. The majority of stars in our sample reside in the red clump or red hor…
Metallicity of Galactic RR Lyrae from Optical and Infrared Light Curves. II. Period-Fourier-Metallicity Relations for First Overtone RR Lyrae
Dall'Ora, Massimo; Bono, Giuseppe; Fiorentino, Giuliana +11 more
We present new period-ϕ 31-[Fe/H] relations for first-overtone RRL stars (RRc), calibrated over a broad range of metallicities (-2.5 ≲ [Fe/H] ≲ 0.0) using the largest currently available set of Galactic halo field RRL with homogeneous spectroscopic metallicities. Our relations are defined in the optical (ASAS-SN V band) and, inaugurally…