Search Publications
Measuring the Magnetic Field of Young Stars Using iSHELL Observations: BP Tau and V347 Aur
Flores, C.; Boogert, A.; Connelley, M. S. +1 more
While it has been suggested that there is a connection between the magnetic properties and the internal structure of young stars, there have not been enough magnetic measurements to firmly establish such a correlation at the earliest ages. Here, we contribute to this endeavor by presenting stellar parameters and magnetic field strength measurement…
Broadband Spectral Energy Distributions of SDSS-selected Quasars and of Their Host Galaxies: Intense Activity at the Onset of AGN Feedback
Lapi, Andrea; Gilli, Roberto; Baccigalupi, Carlo +3 more
We present the mean spectral energy distribution (SED) of a sample of optically selected quasars (QSOs) at redshifts of 1 ≤ z ≤ 5. To derive it, we exploit photometric information from the Sloan Digital Sky Survey, UKIRT Infrared Deep Sky Survey, and Wide-field Infrared Survey Explorer surveys in combination with a stacking analysis of Herschel, A…
Star Formation Histories of the LEGUS Spiral Galaxies. I. The Flocculent Spiral NGC 7793
Cignoni, M.; Tosi, M.; Sabbi, E. +13 more
We present a detailed study of the flocculent spiral galaxy NGC 7793, part of the Sculptor group. By analyzing the resolved stellar populations of the galaxy, located at a distance of ∼3.7 Mpc, we infer for the first time its radial star formation history (SFH) from Hubble Space Telescope photometry, thanks to both archival and new data from the L…
A Two-sided Loop X-Ray Solar Coronal Jet Driven by a Minifilament Eruption
Harra, Louise K.; Moore, Ronald L.; Sterling, Alphonse C. +1 more
Most of the commonly discussed solar coronal jets are the type that consist of a single spire extending approximately vertically from near the solar surface into the corona. Recent research supports that eruption of a miniature filament (minifilament) drives many such single-spire jets and concurrently generates a miniflare at the eruption site. A…
Joint X-Ray, EUV, and UV Observations of a Small Microflare
Krucker, Säm; White, Stephen M.; Grefenstette, Brian W. +5 more
We present the first joint observation of a small microflare in X-rays with the Nuclear Spectroscopic Telescope ARray (NuSTAR), in UV with the Interface Region Imaging Spectrograph (IRIS), and in EUV with the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA). These combined observations allow us to study the hot coronal and cooler …
Kinematics of the O VI Circumgalactic Medium: Halo Mass Dependence and Outflow Signatures
Charlton, Jane C.; Kacprzak, Glenn G.; Churchill, Christopher W. +4 more
We probe the high-ionization circumgalactic medium by examining absorber kinematics, absorber-galaxy kinematics, and average absorption profiles of 31 O VI absorbers from the “Multiphase Galaxy Halos” Survey as a function of halo mass, redshift, inclination, and azimuthal angle. The galaxies are isolated at 0.12 < z gal < 0.66 and…
Changes in Solar Rotation over Two Solar Cycles
Basu, Sarbani; Antia, H. M.
We use helioseismic data from ground- and space-based instruments to analyze how solar rotation has changed since the beginning of solar Cycle 23 with emphasis on studying the differences between Cycles 23 and 24. We find that the nature of solar rotation is indeed different for the two cycles. While the changes in the latitudinally independent co…
Noncircular Motions in the Outer Perseus Spiral Arm
Menten, Karl M.; Reid, Mark J.; Sakai, Nobuyuki +2 more
We report measurements of parallax and proper motion for five 6.7 GHz methanol maser sources in the outer regions of the Perseus arm as part of the BeSSeL Survey of the Galaxy. By combining our results with previous astrometric results, we determine an average spiral arm pitch angle of 9.°2 ± 1.°5 and an arm width of 0.39 kpc for this spiral arm. …
Signatures of Tidal Disruption in Ultra-faint Dwarf Galaxies: A Combined HST, Gaia, and MMT/Hectochelle Study of Leo V
Caldwell, Nelson; Strader, Jay; Seth, Anil C. +10 more
The ultra-faint dwarf galaxy Leo V has shown both photometric overdensities and kinematic members at large radii, along with a tentative kinematic gradient, suggesting that it may have undergone a close encounter with the Milky Way. We investigate these signs of disruption through a combination of (i) high precision photometry obtained with the Hu…
Resolved Molecular Gas and Star Formation Properties of the Strongly Lensed z = 2.26 Galaxy SDSS J0901+1814
Wilner, David J.; Keeton, Charles R.; Lutz, Dieter +8 more
We present ∼1″ resolution (∼2 kpc in the source plane) observations of the CO (1-0), CO (3-2), Hα, and [N II] lines in the strongly lensed z = 2.26 star-forming galaxy SDSS J0901+1814. We use these observations to constrain the lensing potential of a foreground group of galaxies, and our source-plane reconstructions indicate that SDSS J0901+1814 i…