Search Publications
A Wide View of the Galactic Globular Cluster NGC 2808: Red Giant and Horizontal Branch Star Spatial Distributions
Rest, Armin; Mastrobuono-Battisti, Alessandra; Johnson, Christian I. +7 more
Wide-field and deep DECam multiband photometry, combined with HST data for the core of the Galactic globular cluster NGC 2808, allowed us to study the distribution of various stellar subpopulations and stars in different evolutionary phases out to the cluster tidal radius. We used the C ugi = (u - g) - (g - i) index to identify three …
Toward more accurate RR Lyrae metallicities
Kovacs, Geza; Jurcsik, Johanna
By using a large sample of fundamental mode RR Lyrae stars with published spectroscopic iron abundances and gravities, we point out the importance of correcting these abundances by using more accurate temporal gravities. For the 197 stars with multiple spectra, overall we find [Fe/H] standard deviations of 0.167 (as published), 0.145 (shifted by d…
Accelerated particle beams in a 3D simulation of the quiet Sun. Lower atmospheric spectral diagnostics
Rouppe van der Voort, L.; Carlsson, M.; Gudiksen, B. V. +2 more
Context. Nanoflare heating through small-scale magnetic reconnection events is one of the prime candidates to explain heating of the solar corona. However, direct signatures of nanoflares are difficult to determine, and unambiguous observational evidence is still lacking. Numerical models that include accelerated electrons and can reproduce flarin…
Galactic properties that favour star cluster formation: a statistical view
Sills, Alison; Eadie, Gwendolyn; Reina-Campos, Marta +1 more
The presence or absence of star clusters in galaxies, and the properties of star cluster populations compared to their host galaxy properties, are important observables for validating models of cluster formation, galaxy formation, and galaxy assembly. In this work, we apply a Bayesian approach to fit two models to data from surveys of young cluste…
Stable Coronal X-Ray Emission over 20 yr of XZ Tau
Schneider, P. C.; Principe, David A.; Wolk, Scott J. +3 more
XZ Tau AB is a frequently observed binary young stellar object in the Taurus Molecular Cloud; XZ Tau B has been classified as an EXOr object. We present new Chandra/HETG-ACIS-S observations of XZ Tau AB, complemented with variability monitoring of the system with XMM-Newton, to constrain the variability of this system and identify high-resolution …
Teutsch 76: A deep near-infrared study
Pandey, Rakesh; Sharma, Saurabh; Dewangan, Lokesh +9 more
We have performed a detailed analysis on the Teutsch 76 (T76) open cluster using the deep near-infrared (NIR) observations taken with the TANSPEC instrument mounted on the 3.6m Devasthal optical telescope along with the recently available high quality proper motion data from the Gaia data release 3 and deep photometric data from Pan-STARRS1 survey…
Multipoint Observations of Dispersive Scale Alfvénic Field-Line Resonances Associated With Substorm Auroral Beads
Frey, Harald U.; Wing, Simon; Chaston, Christopher C. +2 more
We present a case study of the field-aligned current (FAC) systems that transpire within the high-altitude auroral acceleration region of an "auroral bead" initiated double oval substorm observed on 23 February 2001 by the Cluster fleet. Conjunctive Cluster measurements and auroral images from IMAGE reveal that auroral bead current system formatio…
Identifying and characterizing the most heavily dust-obscured galaxies at 1 ≤ z ≤ 4
Willott, Chris J.; Martis, Nicholas S.; Muzzin, Adam +2 more
We present 65 extremely dust-obscured galaxies from the UltraVISTA DR3 survey of the COSMOS field at 1 < z < 4. In contrast to other studies of dusty galaxies, we select our sample based on dust attenuation measured by UV-MIR spectral energy distribution (SED) modelling that allows for extreme attenuation levels. We construct our sample by m…
Polarimetry of the potential binary supermassive black hole system in J1430+2303
Antonucci, R.; Blinov, D.; Liodakis, I. +6 more
Context. The growth of supermassive black holes (SMBHs) through merging has long been predicted but its detection remains elusive. However, a promising target has been discovered in the Seyfert-1 galaxy J1430+2303, where two SMBHs may be about to merge.
Aims: If a binary system truly lies at the center of J1430+2303, the usual symmetry expect…
Estimation of stellar parameters and mass accretion rate of classical T Tauri stars from LAMOST DR6
Mathew, Blesson; Kartha, Sreeja S.; Shridharan, B. +3 more
Classical T Tauri stars (TTS) are low-mass pre-main sequence stars with an active circumstellar environment. In this work, we present the identification and study of 260 classical TTS using LAMOST Data Release 6, among which 104 stars are newly identified. We distinguish classical TTS from giants and main-sequence dwarfs based on the