Search Publications
Uniform Forward-modeling Analysis of Ultracool Dwarfs. II. Atmospheric Properties of 55 Late-T Dwarfs
Line, Michael R.; Marley, Mark S.; Liu, Michael C. +2 more
We present a large uniform forward-modeling analysis for 55 late-T (T7-T9) dwarfs, using low-resolution (R ≈ 50-250) near-infrared (1.0-2.5 µm) spectra and cloudless Sonora-Bobcat model atmospheres. We derive the objects' effective temperatures, surface gravities, metallicities, radii, masses, and bolometric luminosities using our newly deve…
Revisiting the Distance to Radio Loops I and IV Using Gaia and Radio/Optical Polarization Data
Dickinson, C.; Pearson, T. J.; Panopoulou, G. V. +2 more
Galactic synchrotron emission exhibits large angular scale features known as radio spurs and loops. Determining the physical size of these structures is important for understanding the local interstellar structure and for modeling the Galactic magnetic field. However, the distance to these structures is either under debate or entirely unknown. We …
Simultaneous Multiwavelength Flare Observations of EV Lacertae
Hamaguchi, Kenji; Barclay, Thomas; Davenport, James R. A. +17 more
We present the first results of our ongoing project conducting simultaneous multiwavelength observations of flares on nearby active M dwarfs. We acquired data of the nearby dM3.5e star EV Lac using five different observatories: NASA's Transiting Exoplanet Survey Satellite (TESS), NASA's Neil Gehrels Swift Observatory (Swift), NASA's Neutron Interi…
The Atacama Cosmology Telescope: Detection of Millimeter-wave Transient Sources
Hilton, Matt; Choi, Steve K.; Dünner, Rolando +29 more
We report on the serendipitous discovery of three transient millimeter-wave sources using data from the Atacama Cosmology Telescope. The first, detected at R.A. = 273.8138, decl. = -49.4628 at ~50σ total, brightened from less than 5 mJy to at least 1100 mJy at 150 GHz with an unknown rise time shorter than 13 days, during which the increase from 2…
Unveiling the star formation history of the Upper Scorpius association through its kinematics
Gratton, Raffaele; Bonavita, Mariangela; Squicciarini, Vito +1 more
Stellar associations can be discerned as overdensities of sources not only in the physical space but also in the velocity space. The common motion of their members, gradually eroded by the galactic tidal field, is partially reminiscent of the initial kinematic structure. Using recent data from Gaia EDR3, combined with radial velocities from GALAH …
Measuring the density structure of an accretion hot spot
Reynolds, M.; Romanova, M. M.; Calvet, N. +5 more
Magnetospheric accretion models predict that matter from protoplanetary disks accretes onto stars via funnel flows, which follow stellar magnetic field lines and shock on the stellar surfaces1-3, leaving hot spots with density gradients4-6. Previous work has provided observational evidence of varying density in hot spots…
The Gravity Collective: A Search for the Electromagnetic Counterpart to the Neutron Star-Black Hole Merger GW190814
Conselice, Christopher J.; Filippenko, Alexei V.; Kilpatrick, Charles D. +80 more
We present optical follow-up imaging obtained with the Katzman Automatic Imaging Telescope, Las Cumbres Observatory Global Telescope Network, Nickel Telescope, Swope Telescope, and Thacher Telescope of the LIGO/Virgo gravitational wave (GW) signal from the neutron star-black hole (NSBH) merger GW190814. We searched the GW190814 localization region…
Extreme ultra-soft X-ray variability in an eROSITA observation of the narrow-line Seyfert 1 galaxy 1H 0707-495
Buchner, J.; Nandra, K.; Merloni, A. +9 more
The ultra-soft narrow-line Seyfert 1 galaxy 1H 0707-495 is a well-known and highly variable active galactic nucleus (AGN), with a complex, steep X-ray spectrum, and has been studied extensively with XMM-Newton. 1H 0707-495 was observed with the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) aboard the Spectrum-Roentgen-Gamma (S…
The intracluster magnetic field in the double relic galaxy cluster Abell 2345
Lovisari, L.; Vazza, F.; van Weeren, R. J. +5 more
Magnetic fields are ubiquitous in galaxy clusters, yet their radial profile, power spectrum, and connection to host cluster properties are poorly known. Merging galaxy clusters hosting diffuse polarized emission in the form of radio relics offer a unique possibility to study the magnetic fields in these complex systems. In this paper, we investiga…
Anisotropies in Compressible MHD Turbulence: Probing Magnetic Fields and Measuring Magnetization
Lazarian, A.; Hu, Yue; Xu, Siyao
Probing magnetic fields in the interstellar medium (ISM) is notoriously challenging. Motivated by the modern theories of magnetohydrodynamic (MHD) turbulence and turbulence anisotropy, we introduce the Structure Function Analysis (SFA) as a new approach to measure the magnetic-field orientation and estimate the magnetization. We analyze the statis…