Search Publications
Variability in the Massive Open Cluster NGC 1817 from K2: A Rich Population of Asteroseismic Red Clump, Eclipsing Binary, and Main-sequence Pulsating Stars
Vanderburg, Andrew; Stello, Dennis; Grundahl, Frank +13 more
We present a survey of variable stars detected in K2 Campaign 13 within the massive intermediate-age (∼1 Gyr) open cluster NGC 1817. We identify a complete sample of 44 red clump stars in the cluster, and have measured asteroseismic quantities (νmax and/or Δν) for 29 of them. Five stars showed suppressed dipole modes, and the occurrence…
Chandra Observations of High-energy X-Ray Sources Discovered by INTEGRAL
Hare, Jeremy; Rahoui, Farid; Fornasini, Francesca M. +6 more
The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite has detected in excess of 1000 sources in the ∼20-100 keV band during its surveys of the sky over the past 17 years. We obtained 5 ks observations of 15 unclassified INTEGRAL Gamma-Ray (IGR) sources with the Chandra X-ray Observatory in order to localize them, to identify opt…
Vilnius photometry and Gaia astrometry of Melotte 105
Bilir, Selçuk; Yontan, Talar; Canbay, Remziye +1 more
Archival Vilnius CCD photometric observations are presented for the heavily reddened star cluster Melotte 105, resulting in colour-magnitude diagrams and spectral class estimates. There is considerable lack of agreement between studies for reddening, age and distance for this cluster explaining why the archival data are being made available by thi…
V363 Cassiopeiae: a new lithium-rich Galactic Cepheid
Clementini, G.; Ripepi, V.; Molinaro, R. +8 more
Context. Classical Cepheids (DCEPs) are important astrophysical objects not only as standard candles in the determination of the cosmic distance ladder, but also as a testbed for the stellar evolution theory. This is based on the strict connection between their pulsation (period(s) and amplitudes) and stellar parameters (luminosity, mass, effectiv…
Local Molecular Gas toward the Aquila Rift Region
Chen, Zhiwei; Wang, Hongchi; Gong, Yan +11 more
We present the results of a ∼250 square degrees CO mapping (+26° ≲ l ≲ +50° and -5° ≲ b ≲ +5°) toward the Aquila Rift region at a spatial resolution of ∼50″ and a grid spacing of 30″. The high dynamic range CO maps with a spectral resolution of ∼0.2 km s-1 display highly structured molecular cloud (MC) morphologies with valuable velocit…
The Supernova Remnant Population of NGC 6946 as Observed in [Fe II] 1.644 µm with HST
Blair, William P.; Long, Knox S.; Winkler, P. Frank +1 more
NGC 6946 is a high-star-formation-rate, face-on, spiral galaxy that has hosted 10 supernovae since 1917. Not surprisingly, a large number of supernova remnants and candidates have been identified either as optical nebulae with high [S II]:Hα line ratios (147) or as compact non-thermal radio sources (35). However, there are only seven overlaps betw…
TIC 278956474: Two Close Binaries in One Young Quadruple System Identified by TESS
Borkovits, Tamás; Hellier, Coel; Latham, David W. +25 more
We have identified a quadruple system with two close eclipsing binaries in Transiting Exoplanet Survey Satellite (TESS) data. The object is unresolved in Gaia and appears as a single source at parallax 1.08 ± 0.01 mas. Both binaries have observable primary and secondary eclipses and were monitored throughout TESS Cycle 1 (sectors 1-13), falling wi…
Modelling hystereses observed during dwarf nova outbursts
Knigge, C.; Hameury, J. -M.; Lasota, J. -P. +2 more
Context. Although the disc instability model is widely accepted as the explanation for dwarf nova outbursts, it is still necessary to compare its predictions to observations because many of the constraints on angular momentum transport in accretion discs are derived from the application of this model to real systems.
Aims: We test the predict…
The galaxy population within the virial radius of the Perseus cluster
Apai, D.; Stecklum, B.; Meusinger, H. +3 more
Context. The Perseus cluster is one of the most massive nearby galaxy clusters and is fascinating in various respects. Though the galaxies in the central cluster region have been intensively investigated, an analysis of the galaxy population in a larger field is still outstanding.
Aims: This paper investigates the galaxies that are brighter t…
A magnetic snapshot survey of F-type stars
Neiner, C.; Folsom, C. P.; Marsden, S. C. +5 more
We present a spectropolarimetric magnetic snapshot survey of 55 stars which includes 53 F-type stars ranging from spectral types F0 to F9 plus 2 chemically peculiar stars β CrB, and δ Cap. We look for magnetic fields in stars spanning a range of effective temperatures where the transition from fossil to dynamo magnetic fields is believed to occur.…