Search Publications
Measurability of the Nonlinear Response of Electron Distribution Function to Chorus Emissions in the Earth's Radiation Belt
Santolík, O.; Kolmašová, I.; Omura, Y. +1 more
We conduct test particle simulations to study the perturbations in a hot electron velocity distribution caused by a rising chorus element propagating parallel to the ambient magnetic field in the Earth's outer radiation belt. The wavefield is constructed from the nonlinear growth theory of chorus emissions of Omura (2021,
A revised view of the Canis Major stellar overdensity with DECam and Gaia: new evidence of a stellar warp of blue stars
Carballo-Bello, Julio A.; Vivas, A. Katherina; Martínez-Delgado, David +4 more
We present the Dark Energy Camera (DECam) imaging combined with Gaia Data Release 2 (DR2) data to study the Canis Major overdensity. The presence of the so-called Blue Plume stars in a low-pollution area of the colour-magnitude diagram allows us to derive the distance and proper motions of this stellar feature along the line of sight of its hypoth…
Variable Stars in Local Group Galaxies. VI. The Isolated Dwarfs VV 124 and KKr 25
Sarajedini, Ata; Martínez-Vázquez, C. E.; Vivas, A. Katherina +10 more
We present the discovery of variable stars in two isolated dwarf galaxies in the outskirts of the Local Group, VV 124 and KKr 25, using observations with the Hubble Space Telescope. VV 124 hosts stellar populations with a wide range of ages (>10 Gyr until the present) and therefore we find all types of classical pulsators. In VV 124, we detect …
X-ray and ultraviolet observations of the eclipsing cataclysmic variables OV Bootis and SDSS J103533.02+055158.3 with degenerate donors
Schwope, Axel; Traulsen, Iris; Worpel, Hauke
Context. The majority of cataclysmic variables are predicted to be post-period minimum systems with degenerate donor stars, the period bouncers. Owing to their intrinsic faintness, however, only a handful of these systems have so far been securely identified.
Aims: We want to study the X-ray properties of two eclipsing period bouncers, OV Boo…
Lynds Bright Nebulae: sites of possible twisted filaments and ongoing star formation
Dewangan, L. K.; Ojha, D. K.; Baug, T. +2 more
The paper presents an analysis of multiwavelength data of two Lynds Bright Nebulae (LBNs), LBN 140.07+01.64 and LBN 140.77-1.42. The 1420-MHz continuum map reveals an extended Y-shaped feature (linear extent ~3.7°), which consists of a linear part and a V-like structure. The sites LBN 140.07+01.64 and AFGL 437 are located towards the opposite side…
Occultation of a Large Star by the Large Plutino (28978) Ixion on 2020 October 13 UTC
Bosh, Amanda S.; Person, Michael J.; Levine, Stephen E. +3 more
We observed the occultation of the star Gaia DR2 4056440205544338944 by (28978) Ixion. The event was observed from two Lowell Observatory sites, using the 4.3 m Lowell Discovery Telescope (LDT), near Happy Jack, AZ, USA, and a 0.32 m telescope co-mounted with the Titan Monitoring telescope on Lowell's Mars Hill campus in Flagstaff, AZ. The LDT cho…
New insights into the use of Ultra Long Period Cepheids as cosmological standard candles
Marconi, Marcella; Molinaro, Roberto; Ripepi, Vincenzo +4 more
Ultra Long Period Cepheids (ULPs) are pulsating variable stars with a period longer than 80 d and have been hypothesized to be the extension of the Classical Cepheids (CCs) at higher masses and luminosities. If confirmed as standard candles, their intrinsic luminosities, ∼1 to ∼3 mag brighter than typical CCs, would allow to reach the Hubble flow …
Radial Segregation between Red Giant Populations in the Globular Cluster NGC 3201: Tentative Role of Varying Mass among the Progenitors
Kravtsov, Valery; Calderón, Francisco A.
In the globular cluster NGC 3201, we study subpopulations (SPs) of red giants (RGs) distinguished by their characteristics. In its central part, we make use of multicolor Hubble Space Telescope (HST) photometry coupled with spectroscopy of RGs spread out over a larger cluster face. In the color index CI $=\,({m}_{{\rm{F}}275{\rm{W}}}-{m}_{{\rm{F}}…
The X-rays wind connection in PG 2112+059
Bauer, F. E.; Brandt, W. N.; Chartas, G. +4 more
We study the connection between the X-ray and ultraviolet (UV) properties of the broad absorption line (BAL) wind in the highly X-ray variable quasar PG 2112+059 by comparing Chandra-ACIS data with contemporaneous UV HST/STIS spectra in three different epochs. We observe a correlation whereby an increase in the equivalent widths (EWs) of the BALs …
SEDBYS: A python-based SED Builder for Young Stars
Davies, Claire L.
Spectral energy distributions (SEDs) are useful primary and complementary tools in the analysis of observations of young stars. However, the process of collating, inspecting, and flux-converting archival photometry and spectroscopy to build spectral energy distributions for young stars is time-consuming. Here, I present SEDBYS (Spectral Energy Dis…